angiotensin-i and Inflammation

Hypertension is a major risk factor for the pathogenesis of vascular dementia and Alzheimer's disease. Chronic activation of the renin-angiotensin system (RAS) contributes substantially to neuroinflammation. We propose that neuroinflammation arising from chronic RAS activation can initiate and potentiate the onset of hypertension and related dementia. Neuroinflammation induced by chronic activation of the RAS plays a key role in the pathogenesis of dementia. Increased levels of pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and transforming growth factor (TGF)-β have been reported in brain tissue of vascular dementia patients and animal models of vascular dementia induced by either angiotensin II infusion or transverse aortic coarctation. It is proposed that neuronal cell death and synaptic dysfunction induced by neuroinflammation lead to cognitive impairment in dementia. The neuroprotective RAS pathway, regulated by angiotensin-converting enzyme 2 (ACE2) which converts angiotensin II into angiotensin-(1-7), can attenuate hypertension and dementia. Furthermore, the use of anti-hypertensive medications in preventing dementia or cognitive decline in hypertensive patients and animal models of dementia have mostly been beneficial. Current evidence suggests a strong link between RAS induced neuroinflammation and the onset of hypertension and dementia, which warrants further investigation. Strategies to counteract an overactive RAS and enhance the neuroprotective arm of the RAS may help prevent or improve cognitive impairment associated with hypertension.

Topics: Angiotensin I; Angiotensin II; Animals; Antihypertensive Agents; Brain; Cytokines; Dementia, Vascular; Humans; Hypertension; Inflammation; Peptide Fragments; Renin-Angiotensin System

Infectious diseases, once believed to be an eradicable public health threat, still represent a leading cause of death worldwide. Environmental and social changes continuously favor the emergence of new pathogens and rapid dissemination around the world. The limited availability of anti-viral therapies and increased antibiotic resistance has made the therapeutic management of infectious disease a major challenge. Inflammation is a primordial defense to protect the host against invading microorganisms. However, dysfunctional inflammatory responses contribute to disease severity and mortality during infections. In recent years, a few studies have examined the relevance of resolution of inflammation in the context of infections. Inflammation resolution is an active integrated process transduced by several pro-resolving mediators, including Annexin A1 and Angiotensin-(1-7). Here, we examine some of the cellular and molecular circuits triggered by pro-resolving molecules and that may be beneficial in the context of infectious diseases.

Topics: Angiotensin I; Annexin A1; Communicable Diseases; Humans; Inflammation; Inflammation Mediators

Pulmonary fibrosis is a chronic, fibrotic lung disease affecting 3 million people worldwide. The ACE2/Ang-(1-7)/MasR axis is of interest in pulmonary fibrosis due to evidence of its anti-fibrotic action. Current scientific evidence supports that inhibition of ACE2 causes enhanced fibrosis. ACE2 is also the primary receptor that facilitates the entry of SARS-CoV-2, the virus responsible for the current COVID-19 pandemic. COVID-19 is associated with a myriad of symptoms ranging from asymptomatic to severe pneumonia and acute respiratory distress syndrome (ARDS) leading to respiratory failure, mechanical ventilation, and often death. One of the potential complications in people who recover from COVID-19 is pulmonary fibrosis. Cigarette smoking is a risk factor for fibrotic lung diseases, including the idiopathic form of this disease (idiopathic pulmonary fibrosis), which has a prevalence of 41% to 83%. Cigarette smoke increases the expression of pulmonary ACE2 and is thought to alter susceptibility to COVID-19. Cannabis is another popular combustible product that shares some similarities with cigarette smoke, however, cannabis contains cannabinoids that may reduce inflammation and/or ACE2 levels. The role of cannabis smoke in the pathogenesis of pulmonary fibrosis remains unknown. This review aimed to characterize the ACE2-Ang-(1-7)-MasR Axis in the context of pulmonary fibrosis with an emphasis on risk factors, including the SARS-CoV-2 virus and exposure to environmental toxicants. In the context of the pandemic, there is a dire need for an understanding of pulmonary fibrotic events. More research is needed to understand the interplay between ACE2, pulmonary fibrosis, and susceptibility to coronavirus infection.

Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Cannabis; Cigarette Smoking; COVID-19; Fibrosis; Humans; Idiopathic Pulmonary Fibrosis; Inflammation; Lung; Pandemics; Peptide Fragments; Proto-Oncogene Mas; Respiration, Artificial; Respiratory Distress Syndrome; Respiratory Insufficiency; Risk Factors; SARS-CoV-2; Spike Glycoprotein, Coronavirus

The most classical view of the renin-angiotensin system (RAS) emphasizes its role as an endocrine regulator of sodium balance and blood pressure. However, it has long become clear that the RAS has pleiotropic actions that contribute to organ damage, including modulation of inflammation. Angiotensin II (Ang II) activates angiotensin type 1 receptors (AT1R) to promote an inflammatory response and organ damage. This represents the pathophysiological basis for the successful use of RAS blockers to prevent and treat kidney and heart disease. However, other RAS components could have a built-in capacity to brake proinflammatory responses. Angiotensin type 2 receptor (AT2R) activation can oppose AT1R actions, such as vasodilatation, but its involvement in modulation of inflammation has not been conclusively proven. Angiotensin-converting enzyme 2 (ACE2) can process Ang II to generate angiotensin-(1-7) (Ang-(1-7)), that activates the Mas receptor to exert predominantly anti-inflammatory responses depending on the context. We now review recent advances in the understanding of the interaction of the RAS with inflammation. Specific topics in which novel information became available recently include intracellular angiotensin receptors; AT1R posttranslational modifications by tissue transglutaminase (TG2) and anti-AT1R autoimmunity; RAS modulation of lymphoid vessels and T lymphocyte responses, especially of Th17 and Treg responses; interactions with toll-like receptors (TLRs), programmed necrosis, and regulation of epigenetic modulators (e.g. microRNAs and bromodomain and extraterminal domain (BET) proteins). We additionally discuss an often overlooked effect of the RAS on inflammation which is the downregulation of anti-inflammatory factors such as klotho, peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α), transient receptor potential ankyrin 1 (TRPA1), SNF-related serine/threonine-protein kinase (SNRK), serine/threonine-protein phosphatase 6 catalytic subunit (Ppp6C) and n-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP). Both transcription factors, such as nuclear factor κB (NF-κB), and epigenetic regulators, such as miRNAs are involved in downmodulation of anti-inflammatory responses. A detailed analysis of pathways and targets for downmodulation of anti-inflammatory responses constitutes a novel frontier in RAS research.

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Autoimmunity; Blood Pressure; Gene Expression Regulation; Humans; Inflammation; Kidney; Klotho Proteins; Peptide Fragments; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Renin-Angiotensin System; Signal Transduction; T-Lymphocytes; Water-Electrolyte Balance

Inflammation is generally accepted as a component of the host defence system and a protective response in the context of infectious diseases. However, altered inflammatory responses can contribute to disease in infected individuals. Many endogenous mediators that drive the resolution of inflammation are now known. Overall, mediators of resolution tend to decrease inflammatory responses and provide normal or greater ability of the host to deal with infection. In the lung, it seems that pro-resolution molecules, or strategies that promote their increase, tend to suppress inflammation and lung injury and facilitate control of bacterial or viral burden. Here, we argue that the demonstrated anti-inflammatory, pro-resolving, anti-thrombogenic and anti-microbial effects of such endogenous mediators of resolution may be useful in the treatment of the late stages of the disease in patients with COVID-19.

Topics: Acetates; Angiotensin I; Animals; Annexin A1; Anti-Inflammatory Agents; COVID-19; COVID-19 Drug Treatment; Disease Models, Animal; Docosahexaenoic Acids; Humans; Hydrogen Peroxide; Inflammation; Inflammation Mediators; Mice; Orthomyxoviridae Infections; Oxidants; Peptide Fragments; Peptides; Phosphodiesterase 4 Inhibitors; Pneumonia, Viral; Rolipram; Vasodilator Agents

Fever in infections correlates with inflammation, macrophage infiltration into the affected organ, macrophage activation, and release of cytokines involved in immune response, hematopoiesis, and homeostatic processes. Angiotensin-converting enzyme 2 (ACE2) is the canonical cell surface receptor for SARS-CoV-2. ACE2 together with angiotensin receptor types 1 and 2 and ACE2 are components of the renin-angiotensin system (RAS). Exacerbated production of cytokines, mainly IL-6, points to macrophages as key to understand differential COVID-19 severity. SARS-CoV-2 may modulate macrophage-mediated inflammation events by altering the balance between angiotensin II, which activates angiotensin receptor types 1 and 2, and angiotensin 1-7 and alamandine, which activate

Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Betacoronavirus; Coronavirus Infections; COVID-19; Humans; Inflammation; Interleukin-6; Macrophages; Pandemics; Peptide Fragments; Peptidyl-Dipeptidase A; Pneumonia, Viral; Proto-Oncogene Mas; Proto-Oncogene Proteins; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, G-Protein-Coupled; Receptors, Virus; Renin-Angiotensin System; SARS-CoV-2

Nowadays the adipose tissue is recognized as one of the most critical endocrine organs releasing many adipokines that regulate metabolism, inflammation and body homeostasis. There are several described adipokines, including the renin-angiotensin system (RAS) components that are especially activated in some diseases with increased production of angiotensin II and several pro-inflammatory hormones. On the other hand, RAS also expresses angiotensin-(1-7), which is now recognized as the main peptide on counteracting Ang II effects. New studies have shown that increased activation of ACE2/Ang-(1-7)/MasR arm can revert and prevent local and systemic dysfunctions improving lipid profile and insulin resistance by modulating insulin actions, and reducing inflammation. In this context, the present review shows the interaction and relevance of Ang-(1-7) effects on regulating adipokines, and as one adipokine itself, modulating body homeostasis, with emphasis on its anti-inflammatory properties, especially in the context of metabolic disorders with focus on obesity and type 2 diabetes mellitus pandemic.

Topics: Adipokines; Adipose Tissue; Angiotensin I; Animals; Humans; Inflammation; Peptide Fragments; Proto-Oncogene Mas

The renin-angiotensin system (RAS) conceived as a coordinated hormonal cascade plays an important role in controlling multiple functions in many organs and is much more complex than previously thought. The RAS has continued to expand, with the identification of new components, functions and subsystems. Angiotensin-converting enzyme (ACE) and its novel homolog angiotensin converting enzyme 2 (ACE2) are two key enzymes involved in the synthesis of bioactive components of the RAS. The main active peptides of the RAS include angiotensin II (Ang II), Ang III, Ang IV, and angiotensin-(1-7) [Ang-(1-7)] among which Ang II and Ang-(1-7) are much more important in health and disease. The axis formed by ACE2 represents an endogenous counter-regulatory pathway within the RAS, and its actions are opposite to those of the ACE axis. Conventionally the RAS has been considered to be important in the cardiovascular system, metabolism, cell growth and homeostasis. In recent years, a key role of ACE and ACE2 and their peptides has been recognized in the inflammatory process in conditions such as cardiac hypertrophy, pulmonary hypertension, glomerulonephritis, lung injury, sepsis, and acute pancreatitis. Investigations are ongoing to better understand the role of the RAS in inflammation. A comprehensive understanding of the RAS components in inflammation can provide new possibilities for therapeutic approaches against inflammatory diseases. In this review, we discuss our current understanding of the subject, based on recent findings, on the role of ACE and ACE2 in inflammation.

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Humans; Inflammation; Peptide Fragments; Peptidyl-Dipeptidase A; Renin-Angiotensin System

Electrical, contractile and structural remodeling have been characterized in atrial fibrillation (AF), and the latter is considered to be the major contributor to AF persistence. Recent data show that interstitial fibrosis can predispose to atrial conduction impairment and AF induction. The interplay between cardiac matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitors of MMPs (TIMPs), is thought to be critical in atrial extracellular matrix (ECM) metabolism. At the molecular level, angiotensin II, transforming growth factor-beta1, inflammation and oxidative stress are particularly important for ECM dysregulation and atrial fibrotic remodeling in AF. Therefore, we review recent advances in the understanding of the atrial fibrotic process, the major downstream components in this remodeling process, and the expression and regulation of MMPs and TIMPs. We also describe the activation of bioactive molecules in both clinical studies and animal models to modulate MMPs and TIMPs and their effects on atrial fibrosis in AF.

Topics: Angiotensin I; Angiotensin II; Animals; Antihypertensive Agents; Atrial Fibrillation; Endomyocardial Fibrosis; Heart Atria; Humans; Inflammation; Matrix Metalloproteinases; Models, Biological; Oxidative Stress; Peptide Fragments; ras GTPase-Activating Proteins; Signal Transduction; Tissue Inhibitor of Metalloproteinases; Transforming Growth Factor beta1; Ventricular Remodeling

Type 2 diabetes mellitus (T2DM) is an increasing problem in childhood; however type 1 diabetes mellitus (T1DM) remains by far the most common type of diabetes in this age group. In this review we will focus on T1DM, because this will have the greatest implication for patients diagnosed in childhood. During the atherosclerotic process, several molecular, receptorial and cellular factors provide a continous mechanism of vascular damage. In diabetic children this state seems to be enhanced and facilitated so that accelerated atherosclerosis is associated with an increased risk of cardiovascular events in respect to the non diabetic population. Hyperglycemia PER SE and associated with diabetes is an important risk factor for atherosclerosis. At present a substantial part of children with diabetes do not reach satisfactory glycemic control. Other risk factors for the development and progression of atherosclerosis may be inherited or develop in the course of the disease: hypertension, dyslipidemia, insulin resistance, obesity, cigarette smoking, physical inactivity, disturbance of platelet function, coagulation and fibrinolysis. The development and progression of atherosclerosis should be blocked at an early age, if possible. Primary prevention to all risk factors for cardiovascular disease is important and intervention is indicated if necessary. At the moment the best therapeutic strategy is to maintain metabolic control at a physiologic level and perform screening and early intervention for vascular complications.

Topics: Adult; Angiotensin I; Angiotensin II; Atherosclerosis; Child; Cholesterol, LDL; Diabetic Angiopathies; Fatty Liver; Humans; Inflammation; Macrophages; Thrombosis

Chymase is a chymotrypsin-type serine protease mainly localized in mast cells (MCs). Human, primate, and dog chymase generate angiotensin II (Ang II) from Ang I, while mouse and rat chymases degrade Ang II. It is suggested that chymase generating Ang II might be an alternative Ang II-forming enzyme to angiotensin-converting enzyme (ACE) in the renin-angiotensin system in tissues, but not in blood, and cause hypertrophy and remodeling of cardiovascular tissues. Chymase also degrades extracellular matrix, and processes procollagenase, inflammatory cytokines and other bioactive peptides. As a result, chymase plays important roles in inflammatory tissues through its proteolytic activities to cause tissue remodeling, that is, a chymase inhibitor may have the ability to prevent diseases caused by the above inflammatory reactions. The investigation of chymase inhibitors by pharmaceutical companies has yielded peptide and peptide mimetic inhibitors. We also found potent non-peptide low molecular inhibitors. However, the in vivo functions of chymase have not been verified so far by applying a chymase inhibitor to in vivo pathological models. In this article, we overview the pathophysiological roles of chymase and chymase inhibitors proposed to date, and discuss the structure-activity relationships of substituted 3-phenylsulfonyl-1-phenylimidazolidine-2,4-dione derivatives.

Topics: Angiotensin I; Angiotensin II; Animals; Cardiovascular Diseases; Chymases; Cytokines; Humans; Inflammation; Peptidyl-Dipeptidase A; Serine Endopeptidases; Serine Proteinase Inhibitors; Species Specificity; Structure-Activity Relationship

High mortality of haemodialysis patients is associated with systemic chronic inflammation and overactivation of the renin-angiotensin system (RAS). Insufficient elimination of pro-inflammatory immune mediators, especially in the molecular weight range of 15-45 kDa, may be one of the reasons for this. Employment of haemodialysis membranes with increased permeability was shown to ameliorate the inflammatory response and might modulate the effects of local RAS. In this study, we tested the impact of high cut-off (HCO), medium cut-off (MCO) and high-flux (HF) dialysis on leucocytic transcripts of angiotensin-converting enzymes (ACE and ACE2). Additionally, the impact of HCO, MCO and HF sera and dialysates on local ACEs and inflammation markers was tested in THP-1 monocytes.. Patients' leucocytes were obtained from our recent clinical studies comparing HCO and MCO dialysers with HF. The cells were subjected to quantitaive polymerase chain reaction (qPCR) analyses with TaqMan probes specific for ACE, ACE2 and angiotensin II (AngII) and Ang1-7 receptors. Sera and dialysates from the clinical trials as well as samples from in vitro dialysis were tested on THP-1 monocytic cells. The cells were subjected to qPCR analyses with TaqMan probes specific for ACE, ACE2, interleukin-6 and tumour necrosis factor α and immunocytochemistry with ACE and ACE2 antibodies.. Leucocytes obtained from patients treated with HCO or MCO demonstrated decreased transcript expression of ACE, while ACE2 was significantly upregulated as compared with HF. Receptors for AngII and Ang1-7 remained unchanged. THP-1 monocytes preconditioned with HCO and MCO patients' or in vitro dialysis sera reflected the same expressional regulation of ACE and ACE2 as those observed in HCO and MCO leucocytes. As a complementary finding, treatment with HCO and MCO in vitro dialysates induced a pro-inflammatory response of the cells as demonstrated by elevated messenger RNA expression of tumour necrosis factor α and interleukin-6, as well as upregulation of ACE and decreased levels of ACE2.. Taken together, these data demonstrate that employment of membranes with high permeability eliminates a spectrum of mediators from circulation that affect the RAS components in leucocytes, especially ACE/ACE2.

Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Biomarkers; Cross-Over Studies; Dialysis Solutions; Double-Blind Method; Humans; Inflammation; Inflammation Mediators; Monocytes; Peptide Fragments; Peptidyl-Dipeptidase A; Pilot Projects; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Renal Dialysis

Clinical trials have demonstrated that agents that inhibit the angiotensin II pathway confer benefit beyond the reduction of blood pressure alone. However, the molecular mechanism underlying this effect has yet to be investigated. Recently, we have demonstrated enhanced expression of inducible cyclooxygenase (COX) and prostaglandin (PG)E2-dependent synthase (COX-2/mPGES-1) in human symptomatic plaques and provided evidence that it is associated with metalloproteinase (MMP)-induced plaque rupture. Thus, the aim of this study was to characterize the effect of the angiotensin II type 1 (AT1) receptor antagonist irbesartan on the inflammatory infiltration and expression of COX-2/mPGES-1 and MMPs in human carotid plaques.. Seventy patients with symptomatic carotid artery stenosis were randomized to irbesartan (300 mg/d) or chlorthalidone (50 mg/d) for 4 months before endarterectomy. Plaques were subjected to analysis of COX-1, COX-2, mPGES-1, MMP-2, and MMP-9, angiotensin II, AT(1), AT2, and collagen content by immunocytochemistry, Western blot, and reverse-transcriptase polymerase chain reaction, whereas zymography was used to detect MMP activity. Immunohistochemistry was also used to identify CD68+ macrophages, CD3+ T lymphocytes, smooth muscle cells (SMCs), and HLA-DR+ inflammatory cells. Plaques from the irbesartan group had fewer (P<0.0001) macrophages, T lymphocytes, and HLA-DR+ cells; less (P<0.0001) immunoreactivity for COX-2/mPGES-1 and MMPs; reduced (P<0.0001) gelatinolytic activity; and increased (P<0.0001) collagen content. It is worth noting that COX-2/mPGES-1 inhibition was observed after incubation in vitro with irbesartan but not with the selective AT2 blockade PD123,319.. This study demonstrates that irbesartan decreases inflammation and inhibits COX-2/mPGES-1 expression in plaque macrophages, and this effect may in turn contribute to plaque stabilization by inhibition of MMP-induced plaque rupture.

Topics: Aged; Angiotensin I; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Antihypertensive Agents; Biphenyl Compounds; Carotid Artery, Internal; Carotid Stenosis; Chlorthalidone; Collagen; Combined Modality Therapy; Cyclooxygenase 1; Cyclooxygenase 2; Depression, Chemical; Dinoprostone; Endarterectomy, Carotid; Enzyme Induction; Extracellular Matrix; Female; Gene Expression Regulation; Humans; Inflammation; Intramolecular Oxidoreductases; Irbesartan; Isoenzymes; Macrophages; Male; Matrix Metalloproteinase Inhibitors; Membrane Proteins; Prostaglandin-E Synthases; Prostaglandin-Endoperoxide Synthases; Protease Inhibitors; Rupture, Spontaneous; Tetrazoles

Topics: Acetylcholine; Alzheimer Disease; Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Cognition; Inflammation; Peptide Fragments; Peptidyl-Dipeptidase A; Phenotype; Rats; Reactive Oxygen Species; Receptors, G-Protein-Coupled; Streptozocin

Nonphlogistic migration of macrophages contributes to the clearance of pathogens and apoptotic cells, a critical step for the resolution of inflammation and return to homeostasis. Angiotensin-(1-7) [Ang-(1-7)] is a heptapeptide of the renin-angiotensin system that acts through Mas receptor (MasR). Ang-(1-7) has recently emerged as a novel proresolving mediator, yet Ang-(1-7) resolution mechanisms are not fully determined. Herein, Ang-(1-7) stimulated migration of human and murine monocytes/macrophages in a MasR-, CCR2-, and MEK/ERK1/2-dependent manner. Pleural injection of Ang-(1-7) promoted nonphlogistic mononuclear cell influx alongside increased levels of CCL2, IL-10, and macrophage polarization toward a regulatory phenotype. Ang-(1-7) induction of CCL2 and mononuclear cell migration was also dependent on MasR and MEK/ERK. Of note, MasR was upregulated during the resolution phase of inflammation, and its pharmacological inhibition or genetic deficiency impaired mononuclear cell recruitment during self-resolving models of LPS pleurisy and E. coli peritonitis. Inhibition/absence of MasR was associated with reduced CCL2 levels, impaired phagocytosis of bacteria, efferocytosis, and delayed resolution of inflammation. In summary, we have uncovered a potentially novel proresolving feature of Ang-(1-7), namely the recruitment of mononuclear cells favoring efferocytosis, phagocytosis, and resolution of inflammation. Mechanistically, cell migration was dependent on MasR, CCR2, and the MEK/ERK pathway.

Topics: Angiotensin I; Animals; Cells, Cultured; Disease Models, Animal; Humans; Inflammation; Macrophages; Male; MAP Kinase Signaling System; Mice; Mice, Inbred BALB C; Monocytes; Peptide Fragments; Peritonitis; Phagocytosis; Phenotype; Proto-Oncogene Mas; Receptors, CCR2

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Chickens; Inflammation; Muscle, Smooth, Vascular; Peptide Fragments; Peptides; Peptidyl-Dipeptidase A; Rats; Receptors, G-Protein-Coupled

Angiotensin-(1-7) [Ang-(1-7)]/Mas receptor is a counter-regulatory axis that counteracts detrimental renin-angiotensin system (RAS) effects, especially regarding systemic inflammation, vasopressin (AVP) release, and hypothalamic-pituitary-adrenal (HPA) activation. However, it is not completely understood whether this system may control centrally or systemically the late phase of systemic inflammation. Thus, the aim of this study was to determine whether intracerebroventricular (i.c.v.) administration of Ang-(1-7) can modulate systemic inflammation through the activation of humoral pathways in late phase of endotoxemia. Endotoxemia was induced by systemic injection of lipopolysaccharide (LPS) (1.5 mg/kg, i.v.) in Wistar rats. Ang-(1-7) (0.3 nmol in 2 µL) promoted the release of AVP and attenuated interleukin-6 (IL-6) and nitric oxide (NO) levels but increased interleukin-10 (IL-10) in the serum of the endotoxemic rats. The central administration of Mas receptor antagonist A779 (3 nmol in 2 µL, i.c.v.) abolished these anti-inflammatory effects in endotoxemic rats. Furthermore, Ang-(1-7) applied centrally restored mean arterial blood pressure (MABP) without affecting heart rate (HR) and prevented vascular hyporesponsiveness to norepinephrine (NE) and AVP in animals that received LPS. Together, our results indicate that Ang-(1-7) applied centrally promotes a systemic anti-inflammatory effect through the central Mas receptor and activation of the humoral pathway mediated by AVP.

Topics: Angiotensin I; Animals; Endotoxemia; Gene Expression Regulation; Hypotension; Inflammation; Lactic Acid; Lipopolysaccharides; Male; Osmolar Concentration; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Rats, Wistar; Receptors, G-Protein-Coupled; Sodium; Vasopressins

Defective absorption of acute allergic airway inflammation is involved in the initiation and development of chronic asthma. After allergen exposure, there is a rapid recruitment of macrophages around the airways, which promote acute inflammatory responses. The Ang-(1-7)/Mas receptor axis reportedly plays protective roles in various tissue inflammation and remodeling processes in vivo. However, the exact role of Mas receptor and their underlying mechanisms during the pathology of acute allergic airway inflammation remains unclear.. We investigated the role of Mas receptor in acute allergic asthma and explored its underlying mechanisms in vitro, aiming to find critical molecules and signal pathways.. Mas receptor expression was assessed in ovalbumin (OVA)-induced acute asthmatic murine model. Then we estimated the anti-inflammatory role of Mas receptor in vivo and explored expressions of several known inflammatory cytokines as well as phosphorylation levels of MAPK pathways. Mas receptor functions and underlying mechanisms were studied further in the human bronchial epithelial cell line (16HBE).. Mas receptor expression decreased in acute allergic airway inflammation. Multiplex immunofluorescence co-localized Mas receptor and EpCAM, indicated that Mas receptor may function in the bronchial epithelium. Activating Mas receptor through AVE0991 significantly alleviated macrophage infiltration in airway inflammation, accompanied with down-regulation of CCL2 and phosphorylation levels of MAPK pathways. Further studies in 16HBE showed that AVE0991 pre-treatment inhibited LPS-induced or anisomycin-induced CCL2 increase and THP-1 macrophages migration via JNK pathways.. Our findings suggested that Mas receptor activation significantly attenuated CCL2 dependent macrophage recruitments in acute allergic airway inflammation through JNK pathways, which indicated that Mas receptor, CCL2 and phospho-JNK could be potential targets against allergic airway inflammation.

Topics: Acute Disease; Angiotensin I; Animals; Asthma; Chemokine CCL2; Cytokines; Imidazoles; Inflammation; Macrophage Activation; Macrophages; Male; MAP Kinase Signaling System; Mice; Mice, Inbred BALB C; Ovalbumin; Peptide Fragments; Phosphorylation; Proto-Oncogene Mas; Proto-Oncogene Proteins; Receptors, G-Protein-Coupled; Respiratory System

Sepsis-induced myocardial dysfunction is a major cause of death. The present study explored whether angiotensin (Ang)-(1-7), an important biologically active peptide of the renin-angiotensin system, could improve cardiac dysfunction and attenuate inflammation and apoptosis. Experiments were carried out in mice and in neonatal rat cardiomyocytes (NRCMs) treated with lipopolysaccharide (LPS) or Ang-(1-7). Angiotensin converting enzyme 2 (ACE2), Ang-(1-7) and Mas receptor (MasR) expressions were reduced in the mouse left ventricular and NRCM treated with LPS. Ang-(1-7) increased the ejection fraction and fractional shortening of left ventricular, which were reduced upon LPS injection in mice. Ang-(1-7) pre-treatment reversed LPS-induced decreases of α-myosin heavy chain (MHC) and β-MHC, and increases of S100 calcium binding protein A8 (S100A8) and S100A9 in the mouse left ventricular. The LPS-induced increases of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the mouse left ventricular and NRCMs were inhibited by Ang-(1-7) administration. Ang-(1-7) treatment reversed the increases of cleaved-caspase 3, cleaved-caspase 8 and Bax, and the decrease of Bcl2 induced by LPS in the mouse left ventricular and NRCMs. The increases of MAPKs pathway induced by LPS in NRCMs were inhibited by Ang-(1-7). These results indicate that Ang-(1-7) protects against sepsis-associated left ventricular dysfunction induced by LPS, and increases cardiac contractility via attenuating inflammation and apoptosis.

Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Apoptosis; Cardiotonic Agents; Cells, Cultured; Inflammation; Lipopolysaccharides; Male; Mice, Inbred C57BL; Myocytes, Cardiac; Nerve Tissue Proteins; Peptide Fragments; Proto-Oncogene Mas; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled; Sepsis; Ventricular Dysfunction, Left

Sepsis is a frequent cause of kidney injury. The present study investigated whether Alamandine (Ala) could alleviate sepsis-associated renal injury by reducing inflammation and apoptosis. In addition, we investigated downstream signaling pathways modulated by Ala. Studies were performed in mice treated with lipopolysaccharide (LPS) and in the human proximal tubular epithelial cell line HK-2. The increase in serum creatinine, blood urea nitrogen, cystatin C and Fg, and neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 in the kidneys of mice treated with LPS were reduced after administration of Ala. Exposure to LPS increased interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α) in mice and HK-2 cells, but were reduced after Ala treatment. Furthermore, increased levels of cleaved caspase 3, cleaved caspase 7, cleaved caspase 9, cleaved poly (ADP-ribose) polymerase (PARP) and Bax and reduced levels of Bcl2 in LPS-treated mice and HK-2 cells were reversed after Ala administration. In addition, LPS increased the levels of p-PI3K/PI3K, p-Akt/Akt, p-ERK/ERK, p-JNK/JNK, p-p38/p38 and p-FoxO1 in HK-2 cells, and all were reversed after Ala administration. These results indicate that Ala could improve renal function and inhibit inflammation and apoptosis in LPS induced sepsis mouse models. We demonstrated that Ala attenuated LPS induced sepsis by inhibiting the PI3K/Akt and MAPK signaling pathways.

Topics: Angiotensin I; Animals; Apoptosis; Cell Line; Dose-Response Relationship, Drug; Humans; Inflammation; Kidney; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Oligopeptides; Peptide Fragments; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Sepsis; Signal Transduction

The coronavirus disease 19 (COVID-19) pandemic has brought a great threat to global public health. Currently, mounting evidence has shown the occurrence of neurological symptoms in patients with COVID-19. However, the detailed mechanism by which the SARS-CoV-2 attacks the brain is not well characterized. Recent investigations have revealed that a cytokine storm contributes to brain inflammation and subsequently triggers neurological manifestations during the COVID-19 outbreak. Targeting brain inflammation may provide significant clues to the treatment of neurologic complications caused by SARS-CoV-2. Vascular growth factor (VEGF), which is widely distributed in the brain, probably plays a crucial role in brain inflammation via facilitating the recruitment of inflammatory cells and regulating the level of angiopoietins II (Ang II). Also, Ang II is considered as the products of SARS-CoV-2-attacking target, angiotensin-converting enzyme 2 (ACE2). Further investigation of the therapeutic potential and the underlying mechanisms of VEGF-targeted drugs on the neurological signs of COVID-19 are warranted. In any case, VEGF is deemed a promising therapeutic target in suppressing inflammation during SARS-CoV-2 infection with neurological symptoms.

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Betacoronavirus; Blood-Brain Barrier; Brain; Coronavirus Infections; COVID-19; Cytokines; Humans; Inflammation; Pandemics; Peptidyl-Dipeptidase A; Pneumonia, Viral; SARS-CoV-2; Vascular Endothelial Growth Factor A

We previously demonstrated that angiotensin-(1-7) (Ang-(1-7)), an essential endocrine factor, inhibits the NLRP3 inflammasome by regulating reactive oxygen species (ROS) in fibrotic livers. We also demonstrated that the NLRP3 inflammasome contributes to the liver damage induced by pyroptosis after heatstroke. However, the role of Ang-(1-7) in the hepatocytes under heat stress remains uncertain. We aimed to examine the change in angiotensin peptides in the livers affected by heatstroke and the effect on the ROS-NLRP3 inflammatory signalling pathway.

Topics: Angiotensin I; Angiotensin II; Animals; Biomarkers; Heat Stroke; Hepatocytes; Humans; Imidazoles; Inflammasomes; Inflammation; Interleukin-1beta; Liver; Liver Cirrhosis; Male; NLR Family, Pyrin Domain-Containing 3 Protein; Peptide Fragments; Prospective Studies; Pyroptosis; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Signal Transduction

Increasing evidence indicates that decreased brain blood flow, increased reactive oxygen species (ROS) production, and proinflammatory mechanisms accelerate neurodegenerative disease progression such as that seen in vascular contributions to cognitive impairment and dementia (VCID) and Alzheimer's disease and related dementias. There is a critical clinical need for safe and effective therapies for the treatment and prevention of cognitive impairment known to occur in patients with VCID and chronic inflammatory diseases such as heart failure (HF), hypertension, and diabetes. This study used our mouse model of VCID/HF to test our novel glycosylated angiotensin-(1-7) peptide Ang-1-6-O-Ser-Glc-NH2 (PNA5) as a therapy to treat VCID and to investigate circulating inflammatory biomarkers that may be involved. We demonstrate that PNA5 has greater brain penetration compared with the native angiotensin-(1-7) peptide. Moreover, after treatment with 1.0/mg/kg, s.c., for 21 days, PNA5 exhibits up to 10 days of sustained cognitive protective effects in our VCID/HF mice that last beyond the peptide half-life. PNA5 reversed object recognition impairment in VCID/HF mice and rescued spatial memory impairment. PNA5 activation of the Mas receptor results in a dose-dependent inhibition of ROS in human endothelial cells. Last, PNA5 treatment decreased VCID/HF-induced activation of brain microglia/macrophages and inhibited circulating tumor necrosis factor

Topics: Angiotensin I; Animals; Behavior, Animal; Biomarkers; Brain; Cognitive Dysfunction; Dementia, Vascular; Electrocardiography; Glycosylation; Half-Life; Heart Failure; Human Umbilical Vein Endothelial Cells; Humans; Inflammation; Male; Maze Learning; Memory; Mice; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Receptors, G-Protein-Coupled; Spatial Memory; Ventricular Remodeling

The counter-regulatory axis, Angiotensin Converting Enzyme 2, Angiotensin-(1-7), Mas receptor (ACE2/Ang-1-7/MasR), of the renin angiotensin system (RAS) is a potential therapeutic target in stroke, with Ang-(1-7) reported to have neuroprotective effects in pre-clinical stroke models. Here, an extensive investigation of the functional and mechanistic effects of Ang-(1-7) was performed in a rodent model of stroke. Using longitudinal magnetic resonance imaging (MRI) it was observed that central administration of Ang-(1-7) following transient middle cerebral artery occlusion (MCAO) increased the amount of tissue salvage compared to reperfusion alone. This protective effect was not due to early changes in blood brain barrier (BBB) permeability, microglia activation or inflammatory gene expression. However, increases in NADPH oxidase 1 (Nox1) mRNA expression were observed in the treatment group compared to control. In order to determine whether Ang-(1-7) has direct cerebrovascular effects, laser speckle contrast imaging (LSCI) was performed to measure dynamic changes in cortical perfusion following reperfusion. Delivery of Ang-(1-7) did not have any effect on cortical perfusion following reperfusion however; it showed an indication to prevent the 'steal phenomenon' within the contralateral hemisphere. The comprehensive series of studies have demonstrated a moderate protective effect of Ang-(1-7) when given alongside reperfusion to increase tissue salvage.

Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Blood-Brain Barrier; Contrast Media; Disease Models, Animal; Gene Expression Regulation; Humans; Infarction, Middle Cerebral Artery; Inflammation; Magnetic Resonance Imaging; Microglia; Middle Cerebral Artery; NADPH Oxidase 1; Neuroprotective Agents; Peptide Fragments; Peptidyl-Dipeptidase A; Proto-Oncogene Mas; Rats; Renin-Angiotensin System; Reperfusion; RNA, Messenger; Stroke

Angiotensin Converting Enzyme (ACE) 2 is an important modulator of the Renin Angiotensin System (RAS) and the RAS plays a central role in renovascular hypertension. Very few studies investigated the role of components of the counterregulatory RAS axis (ACE2, Ang-(1-7) and Mas receptor) in renovascular hypertension and the results are controversial.. The aim of this study was to investigate the effects of Diminazene Aceturate (DIZE) administration on renal function and renal inflammation parameters in 2K1C hypertensive rats.. Male Wistar rats were divided into three experimental groups: sham-operated animals, 2K1C+saline and 2K1C+DIZE orally (1 mg/kg/day). At the end of the 30 days of treatment, renal function was analyzed and kidneys from all the groups were collected and processed separately for measurement of N-acetyl-beta-D-glucosaminidase (NAG) and Myeloperoxidase (MPO) activities, cytokines, chemokines and nitric oxide levels.. Oral DIZE administration for 4 weeks in hypertensive rats attenuated renal dysfunction and reduced the levels of MPO and NAG, cytokines and chemokines (IL1β, IL-6, TNF-α and MCP-1) and increased urinary nitrate/nitrite levels in 2K1C hypertensive rats.. Our findings showed that ACE2 activation may effectively improve renal alterations and inflammation induced by renovascular hypertension.

Topics: Acetylglucosaminidase; Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Cytokines; Diminazene; Enzyme Activators; Hypertension, Renovascular; Inflammation; Kidney; Male; Nitric Oxide; Peptide Fragments; Peptidyl-Dipeptidase A; Peroxidase; Rats, Wistar; Renin-Angiotensin System

The aim of the present study was to investigate the role of the angiotensin-converting enzyme (ACE)2-angiotensin‑(Ang)-(1-7)-Mas axis in the pathogenesis of pancreatitis and the association between this axis and the p38 mitogen-activated protein kinase (p38 MAPK)/nuclear factor (NF-κB) signaling pathway in pancreatic acinar cells. Mouse pancreatic acinar cancer (MPC-83) cells were stimulated with 10 nM caerulein (CAE) to create an in vitro model of acute pancreatitis, and collected for analysis at 2, 6, 12, 24 and 48 h post stimulation. In addition, cells were pretreated with different concentrations of Ang‑(1‑7), Ang‑(1‑7) antagonist A779, p38 MAPK inhibitor SB203580 or ACE2 inhibitor DX600 for 30 min, and then stimulated with CAE for 24 h. The ACE2, Mas receptor, p38 MAPK, phosphorylated (p)-p38 MAPK and NF-κB expression levels were evaluated using western blotting and immunofluorescence. p38 MAPK, NF-κB, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-8 and IL-10 mRNA expression levels were assessed using reverse transcription-quantitative polymerase chain reaction. The results of the immunofluorescence assay demonstrated that ACE2 and p38 MAPK were present mainly in the cytoplasm, while the Mas receptor was located mainly in the cell membrane. ACE2, p38 MAPK and p-p38 MAPK protein levels were significantly increased (P<0.05) following stimulation with CAE compared with those in the control group and peaked at 24 h. Mas receptor protein levels were significantly upregulated (P<0.05) between 6 and 24 h, peaking at 12 h. Ang‑(1‑7) and SB203580 downregulated p-p38 MAPK and NF-κB expression and the mRNA levels of inflammatory factors IL-6, TNF-α and IL-8, but upregulated the mRNA level of inflammatory factor IL-10 compared with those treated with CAE alone. These results were supported by the opposite outcomes observed for cells treated with A779 or DX600. Therefore, it was concluded that the ACE2-Ang‑(1‑7)-Mas axis significantly inhibits pancreatitis by inhibition of the p38 MAPK/NF-κB signaling pathway.

Topics: Acinar Cells; Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Humans; Imidazoles; Inflammation; Mice; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Pancreas; Peptide Fragments; Peptides; Peptidyl-Dipeptidase A; Proto-Oncogene Mas; Proto-Oncogene Proteins; Pyridines; Receptors, G-Protein-Coupled; Signal Transduction

Evaluating the pro-/anti-inflammatory activity of the C-terminal cleavage product of osteopontin in comparison to angiotensin 1-7.. Human coronary endothelial cells (hcEC) treated with conditioned media from human U937 macrophages.. Macrophages were (pre)treated with C-terminal, full-length or N-terminal osteopontin (OPN-C, OPN-FL, OPN-N, respectively), angiotensin II, angiotensin 1-7 or TNF-α. OPN-C modulatory capacity was compared to that of Ang1-7 in inhibiting subsequent Ag II, OPN-FL or OPN-N-induced macrophage-mediated endothelial inflammation.. Protein expression of NFκB, IκB, vCAM-1 and iCAM-1 was assessed using western blot. Promotor activation by NFκB was also assessed by dual-luciferase reporter assay.. Conditioned media of macrophages treated with OPN-C induced hcECs' NfκB activation to a lower degree than OPN-FL or OPN-N. Priming of macrophages with angiotensin 1-7 attenuated the endothelial pro-inflammatory effect induced by subsequent exposure of the macrophages to angiotensin II, OPN-FL or OPN-N. This was evidenced by both NfκB activation and vCAM and iCAM expression. In contrast, priming macrophages with OPN-C did not significantly attenuate the subsequent response to the pro-inflammatory cytokines.. OPN-C induces lower macrophage-induced endothelial inflammation compared to OPN-FL or OPN-N, but unlike angiotensin 1-7, fails to prevent endothelial inflammation induced by subsequent pro-inflammatory macrophage stimulation.

Topics: Angiotensin I; Cells, Cultured; Endothelial Cells; Humans; I-kappa B Proteins; Inflammation; Intercellular Adhesion Molecule-1; Macrophages; NF-kappa B; Osteopontin; Peptide Fragments; U937 Cells; Vascular Cell Adhesion Molecule-1

Cardiac pressure and humoral factors induce cardiac hypertrophy and fibrosis, which are characterized by increased stiffness, reduced contractility and altered perfusion. Angiotensin II (AngII) is well known to promote this pathology. Angiotensin-converting enzyme (ACE) 2, which cleaves AngII and forms Ang-(1-7), exerts protective anti-hypertrophy and anti-fibrosis effects. A disintegrin and metalloproteinase 17 (ADAM17), a membrane-bound enzyme reported to cleave ACE2, may participate in the pathological process of AngII perfusion-induced heart damage. However, researchers have not clearly determined whether dickkopf-3 (DKK3) regulates the ADAM17/ACE2 pathway and, if so, whether DKK3-mediated regulation is related to the glycogen synthase kinase-3β (GSK-3β)/β-catenin pathway. In this study, we explored whether DKK3 overexpression ameliorates the development of AngII-induced cardiac fibrosis and hypertrophy through the ADAM17/ACE2 and GSK-3β/β-catenin pathways.. Mice were injected with a DKK3-overexpressing adenovirus or vehicle and then infused with AngII or saline using subcutaneously implanted mini-pumps for four weeks. Hearts were stained with hematoxylin-eosin, Masson's trichrome and immunohistochemical markers for histology. Primary fibroblasts were treated with the adenovirus and AngII and then examined using western blotting, EdU (5-ethynyl-2'-deoxyuridine) assays and immunofluorescence. Additionally, siRNA silencing was performed to study the role of DKK3 and the involved pathways.. AngII-induced cardiac hypertrophy and interstitial and perivascular fibrosis were less severe in DKK3-overexpressing mice than in control mice. Moreover, the expression levels of fibrotic genes, such as collagen I and III, and the hypertrophic genes atrial natriuretic peptide (ANP) and beta-myosin heavy chain (β-MHC) were decreased. DKK3 overexpression also exerted a protective effect by inhibiting ADAM17 phosphorylation, thus increasing ACE2 expression and subsequently promoting AngII degradation. Furthermore, this process was mediated by the inhibition of GSK-3β and β-catenin and decreased translocation of β-catenin to the nucleus. On the other hand, the DKK3 knockdown by siRNA achieved opposite results.. DKK3 overexpression substantially alleviated AngII infusion-induced cardiac hypertrophy and fibrosis by regulating ADAM17/ACE2 pathway activity and inhibiting the GSK-3β/β-catenin pathway.

Topics: ADAM17 Protein; Adaptor Proteins, Signal Transducing; Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Animals, Newborn; Apoptosis; beta Catenin; Cardiomegaly; Cell Proliferation; Disease Models, Animal; Fibroblasts; Fibrosis; Glycogen Synthase Kinase 3 beta; Inflammation; Intercellular Signaling Peptides and Proteins; Matrix Metalloproteinases; Mice, Inbred C57BL; Peptide Fragments; Peptidyl-Dipeptidase A; Perfusion; Phosphorylation; Signal Transduction; Smad3 Protein; Transforming Growth Factor beta1

Angiotensin-(1-7) [Ang-(1-7)], a heptapeptide mainly generated from cleavage of AngⅠ and AngⅡ, possesses physiological and pharmacological properties, including anti‑inflammatory and antidiabetic properties. Activation of the phosphoinositide 3-kinase and protein kinase B (PI3K̸Akt) signaling pathway has been confirmed to participate in cardioprotection against hyperglycaemia-induced injury. The aim of the present study was to test the hypothesis that Ang-(1-7) protects H9c2 cardiomyoblast cells against high glucose (HG)-induced injury by activating the PI3K̸Akt pathway. To examine this hypothesis, H9c2 cells were treated with 35 mmol/l (mM) glucose (HG) for 24 h to establish a HG-induced cardiomyocyte injury model. The cells were co-treated with 1 µmol/l (µM) Ang-(1-7) and 35 mM glucose. The findings of the present study demonstrated that exposure of H9c2 cells to HG for 24 h markedly induced injury, as evidenced by an increase in the percentage of apoptotic cells, generation of reactive oxygen species and level of inflammatory cytokines, as well as a decline in cell viability and mitochondrial luminosity. These injuries were significantly attenuated by co-treatment of the cells with Ang-(1-7) and HG. In addition, PI3K̸Akt phosphorylation was suppressed by HG treatment, but this effect was abolished when the H9c2 cells were co-treated with Ang-(1-7) and HG. Furthermore, the cardioprotection of Ang-(1-7) against HG-induced injury in H9c2 cardiomyoblasts was highly attenuated in the presence of either D-Ala7-Ang-(1-7) (A-779, an antagonist of the Mas receptor) or LY294002 (an inhibitor of PI3K̸Akt). In conclusion, the present study provided new evidence that Ang-(1-7) protects H9c2 cardiomyoblasts against HG-induced injury by activating the PI3K̸Akt signaling pathway.

Topics: Angiotensin I; Animals; Apoptosis; Cardiotonic Agents; Caspases; Cell Line; Cell Survival; Cytoprotection; Glucose; Hyperglycemia; Inflammation; Membrane Potential, Mitochondrial; Myocytes, Cardiac; Peptide Fragments; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Rats; Reactive Oxygen Species; Signal Transduction

The present study aimed to investigate the effects of angiotensin (Ang) 1-7 on caerulein (CAE)-stimulated nuclear factor (NF)‑κB, Toll‑like receptor (TLR4) and cytokine expression using pancreatic acinar AR42J cells. AR42J cells were treated with 10 nmol/l CAE for various durations. In addition, cells were pretreated with various concentrations of Ang 1‑7 or A779, a specific antagonist of Ang 1‑7, and were stimulated with CAE for 12 h. Control cells were treated with vehicle (F‑12K complete medium with 2% fetal bovine serum, 10 U/ml penicillin and 100 mg/ml streptomycin) alone. The mRNA and protein expression levels of TLR4, NF‑κB, interleukin (IL)‑6, IL‑8, IL‑10 and tumor necrosis factor‑α (TNF‑α) were determined by western blotting, immunofluorescence and reverse transcription‑quantitative polymerase chain reaction. CAE treatment stimulated TLR4 and NF‑κB expression within AR42J cells. Immunofluorescence indicated that TLR4 was expressed on the membranes and in the cytoplasm of AR42J cells, whereas NF‑κB expression accumulated in the cytoplasm and nuclei. CAE‑induced expression of TLR4 and NF‑κB within AR42J cells was abrogated by 10‑5 mmol/l Ang 1‑7; however, TLR4 and NF‑κB expression was enhanced with the addition of A779, particularly 10‑5 mmol/l. In addition, treatment with 10‑6 and 10‑5 mmol/l Ang 1‑7 significantly mitigated CAE‑induced expression of IL‑6, IL‑8 and TNF‑α, whereas it enhanced IL‑10 expression. Conversely, A779 treatment enhanced the CAE‑induced expression of IL‑6, IL‑8 and TNF‑α, and reduced IL‑10 expression in AR42J cells. In conclusion, these results suggested that Ang 1‑7 may attenuate CAE‑induced inflammation by downregulating TLR4, NF‑κB and proinflammatory cytokine expression within AR42J cells. Therefore, Ang 1‑7 may exert protective effects against the pathological progression of AP in a cell model of AP induced by CAE and may be considered in the development of treatments for this disease.

Topics: Acinar Cells; Angiotensin I; Angiotensin II; Animals; Cell Line; Ceruletide; Down-Regulation; Inflammation; Interleukin-10; Interleukin-6; Microscopy, Fluorescence; NF-kappa B; Peptide Fragments; Rats; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha

Angiotensin (Ang)‑1‑7, which is catalyzed by angiotensin‑converting enzyme 2 (ACE2) from angiotensin‑II (Ang‑II), exerts multiple biological and pharmacological effects, including cardioprotective effects and endothelial protection. The Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway has been demonstrated to be involved in diabetes‑associated cardiovascular complications. The present study hypothesized that Ang‑(1‑7) protects against high glucose (HG)‑induced endothelial cell injury and inflammation by inhibiting the JAK2/STAT3 pathway in human umbilical vein endothelial cells (HUVECs). HUVECs were treated with 40 mmol/l glucose (HG) for 24 h to establish a model of HG‑induced endothelial cell injury and inflammation. Protein expression levels of p‑JAK2, t‑JAK2, p‑STAT3, t‑STAT3, NOX‑4, eNOS and cleaved caspase‑3 were tested by western blotting. CCK‑8 assay was performed to assess cell viability of HUVECs. Apoptotic cell death was analyzed by Hoechst 33258 staining. Mitochondrial membrane potential (MMP) was obtained using JC‑1. Superoxide dismutase (SOD) activity was tested by SOD assay kit. Interleukin (IL)‑1β, IL‑10, IL‑12 and TNF‑α levels in culture media were tested by ELISA. The findings demonstrated that exposure of HUVECs to HG for 24 h induced injury and inflammation. This injury and inflammation were significantly ameliorated by pre‑treatment of cells with either Ang‑(1‑7) or AG490, an inhibitor of the JAK2/STAT3 pathway, prior to exposure of the cells to HG. Exposure of the cells to HG also increased the phosphorylation of JAK2/STAT3 (p‑JAK2 and p‑STAT3). Increased activation of the JAK2/STAT3 pathway was attenuated by pre‑treatment with Ang‑(1‑7). To the best of our knowledge, the findings from the present study provided the first evidence that Ang‑(1‑7) protects against HG‑induced injury and inflammation by inhibiting activation of the JAK2/STAT3 pathway in HUVECs.

Topics: Angiotensin I; Cell Survival; Cytoprotection; Endothelial Cells; Glucose; Human Umbilical Vein Endothelial Cells; Humans; Inflammation; Janus Kinase 2; Oxidative Stress; Peptide Fragments; Protective Agents; Signal Transduction; STAT3 Transcription Factor

Overactivation of angiotensin-converting enzyme/angiotensin 2/angiotensin receptor-1 (ACE/Ang2/AT1) axis provokes amyloid-β-induced apoptosis and neurodegeneration in Alzheimer's disease (AD). Moreover, activation of AT1 impairs the survival pathway phosphoinositide 3-kinase/protein kinase B (PI3K/Akt). Interestingly, the coupling between ACE2/Ang(1-7)/Mas receptor (MasR) axis and PI3K/Akt activation opposes AT1-induced apoptosis. However, the effect of in vivo stimulation of MasR against AD and its correlation to PI3K/Akt is not yet elucidated. Thus, the present study aimed to investigate the relationship between PI3K/Akt pathway and the activation of ACE2/MasR in the AD model of D-galactose-ovariectomized rats. AD features were induced following 8-week injection of D-galactose (150 mg/kg, i.p.) in ovariectomized female rats. The ACE2 activator dimenazine (15 mg/kg, i.p.) was daily administered for 2 months. DIZE administration boosted the hippocampal expression of ACE2 and Mas receptors while suppressing AT1 receptor. Notably, dimenazine enhanced the expression of phosphorylated survival factors (PI3K, Akt, signal transducer, and activator of transcription-3) and neuroplasticity proteins such as cyclic adenosine monophosphate-responsive element-binding protein and brain-derived neurotrophic factor along with nicotinic and glutamatergic receptors. Such effects were accompanied by suppressing phosphorylated tau and glycogen synthase kinase3β along with caspase-3, cytochrome-c, nuclear factor kappa B, tumor necrosis factor alpha, and glial fibrillary acidic protein contents. Dimenazine ameliorated the histopathological damage observed in D-galactose-ovariectomized rats and improved their learning and recognition memory in Morris water maze and novel object recognition tests. In conclusion, dimenazine-induced stimulation of ACE2/Ang(1-7)/Mas axis subdues cognitive deficits in AD most probably through activation of PI3K/Akt pathway.

Topics: Alzheimer Disease; Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Apoptosis; Cell Survival; Cognition; Diminazene; Female; Galactose; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Inflammation; Maze Learning; Nerve Growth Factors; Neuronal Plasticity; Organelle Biogenesis; Ovariectomy; Peptide Fragments; Peptidyl-Dipeptidase A; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Mas; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Rats, Wistar; Receptors, G-Protein-Coupled; Receptors, Glutamate; Receptors, Nicotinic; Signal Transduction; tau Proteins

During the aging process, chronic neuroinflammation induced by microglia is detrimental for the brain and contributes to the etiology of several aging-related neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. As a newly identified axis of renin-angiotensin system, ACE2/Ang-(1-7)/MAS1 axis plays a crucial role in modulating inflammatory responses under various pathological conditions. However, its relationship with aging-related neuroinflammation is less studied so far. In this study, by using SAMP8 mice, an animal model of accelerated aging, we revealed that the neuroinflammation in the aged brain might be attributed to a decreased level of Ang-(1-7). More importantly, we provided evidence that AVE0991, a nonpeptide analogue of Ang-(1-7), attenuated the aging-related neuroinflammation via suppression of microglial-mediated inflammatory response through a MAS1 receptor-dependent manner. Meanwhile, this protective effect might be ascribed to the M2 activation of microglia induced by AVE0991. Taken together, these findings reveal the association of Ang-(1-7) with the inflammatory response in the aged brain and uncover the potential of its nonpeptide analogue AVE0991 in attenuation of aging-related neuroinflammation.

Topics: Aging; Angiotensin I; Animals; Brain; Imidazoles; Inflammation; Mice; Microglia; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Receptors, G-Protein-Coupled

Patients with congestive heart failure (CHF) have increased hospital readmission rates and mortality if they are concomitantly diagnosed with cognitive decline and memory loss. Accordingly, we developed a preclinical model of CHF-induced cognitive impairment with the goal of developing novel protective therapies against CHF related cognitive decline. CHF was induced by ligation of the left coronary artery to instigate a myocardial infarction (MI). By 4- and 8-weeks post-MI, CHF mice had approximately a 50% and 70% decline in ejection fraction as measured by echocardiography. At both 4- and 8-weeks post-MI, spatial memory performance in CHF mice as tested using the Morris water task was significantly impaired as compared with sham. In addition, CHF mice had significantly worse performance on object recognition when compared with shams as measured by discrimination ratios during the novel object recognition NOR task. At 8-weeks post-MI, a subgroup of CHF mice were given Angiotensin (Ang)-(1-7) (50mcg/kg/hr) subcutaneously for 4 weeks. Following 3 weeks treatment with systemic Ang-(1-7), the CHF mice NOR discrimination ratios were similar to shams and significantly better than the performance of CHF mice treated with saline. Ang-(1-7) also improved spatial memory in CHF mice as compared with shams. Ang-(1-7) had no effect on cardiac function. Inflammatory biomarker studies from plasma revealed a pattern of neuroprotection that may underlie the observed improvements in cognition. These results demonstrate a preclinical mouse model of CHF that exhibits both spatial memory and object recognition dysfunction. Furthermore, this CHF-induced cognitive impairment is attenuated by treatment with systemic Ang-(1-7). (PsycINFO Database Record

Topics: Angiotensin I; Animals; Cognitive Dysfunction; Disease Models, Animal; Heart Failure; Inflammation; Male; Maze Learning; Mice; Mice, Inbred C57BL; Myocardial Infarction; Peptide Fragments; Ventricular Remodeling; Visual Acuity

We aimed to study the renal injury and hypertension induced by chronic intermittent hypoxia (CIH) and the protective effects mediated by angiotensin 1-7 [Ang(1-7)]. We randomly assigned 32 male Sprague-Dawley rats (body weight 180-200 g) to normoxia control, CIH, Ang(1-7)-treated normoxia, and Ang(1-7)-treated CIH groups. Systolic blood pressure (SBP) was monitored at the start and end of each week. Renal sympathetic nerve activity (RSNA) was recorded. CTGF and TGF-β were detected by immunohistochemistry and western blotting. Tissue parameters of oxidative stress were also determined. In addition, renal levels of interleukin-6, tumor necrosis factor-α, nitrotyrosine, and hypoxia-inducible factor-1α were determined by immunohistochemistry, immunoblotting, and ELISA. TUNEL assay results and cleaved caspase 3 and 12 were also determined. Ang(1-7) induced a reduction in SBP together with a restoration of RSNA in the rat model of CIH. Ang(1-7) treatment also suppressed the production of reactive oxygen species, reduced renal tissue inflammation, ameliorated mesangial expansion, and decreased renal fibrosis. Thus, Ang(1-7) treatment exerted renoprotective effects on CIH-induced renal injury and was associated with a reduction of oxidative stress, inflammation and fibrosis. Ang(1-7) might therefore represent a promising therapy for obstructive sleep apnea-related hypertension and renal injury.

Topics: Acute Kidney Injury; Angiotensin I; Animals; Disease Models, Animal; Inflammation; Interleukin-6; Kidney; Male; Oxidative Stress; Peptide Fragments; Rats; Rats, Sprague-Dawley

Obesity is increasing in prevalence and is strongly associated with metabolic and cardiovascular disorders. The renin-angiotensin system (RAS) has emerged as a key pathogenic mechanism for these disorders; angiotensin (Ang)-converting enzyme 2 (ACE2) negatively regulates RAS by metabolizing Ang II into Ang 1-7. We studied the role of ACE2 in obesity-mediated cardiac dysfunction. ACE2 null (ACE2KO) and wild-type (WT) mice were fed a high-fat diet (HFD) or a control diet and studied at 6 months of age. Loss of ACE2 resulted in decreased weight gain but increased glucose intolerance, epicardial adipose tissue (EAT) inflammation, and polarization of macrophages into a proinflammatory phenotype in response to HFD. Similarly, human EAT in patients with obesity and heart failure displayed a proinflammatory macrophage phenotype. Exacerbated EAT inflammation in ACE2KO-HFD mice was associated with decreased myocardial adiponectin, decreased phosphorylation of AMPK, increased cardiac steatosis and lipotoxicity, and myocardial insulin resistance, which worsened heart function. Ang 1-7 (24 µg/kg/h) administered to ACE2KO-HFD mice resulted in ameliorated EAT inflammation and reduced cardiac steatosis and lipotoxicity, resulting in normalization of heart failure. In conclusion, ACE2 plays a novel role in heart disease associated with obesity wherein ACE2 negatively regulates obesity-induced EAT inflammation and cardiac insulin resistance.

Topics: Adiponectin; Adipose Tissue; AMP-Activated Protein Kinases; Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Blood Glucose; Blotting, Western; Diet, High-Fat; Enzyme-Linked Immunosorbent Assay; Glucose Intolerance; Heart; Heart Failure; Humans; Inflammation; Insulin Resistance; Macrophages; Mice; Mice, Knockout; Myocardium; Obesity; Oxidative Stress; Peptide Fragments; Peptidyl-Dipeptidase A; Pericardium; Phosphorylation; Real-Time Polymerase Chain Reaction; Stroke Volume; Tumor Necrosis Factor-alpha; Vasodilator Agents; Weight Gain

Inflammation of forebrain and hindbrain nuclei has recently been highlighted as an emerging factor in the pathogenesis of neurogenic hypertension. The aim of this review is to summarize the state of the art in this field and to discuss recently discovered pathophysiological mechanisms, opening new perspectives for therapeutic application.. Microglia Toll-like receptor 4 causally links angiotensin II (AngII)-mediated microglia cell activation and oxidative stress within the hypothalamic paraventricular nucleus (PVN). Toll-like receptor 4 can also be activated by lipopolysaccharides. PVN infusion of nuclear factor κB inhibitor lowers the blood pressure and ameliorates cardiac hypertrophy. Ang-(1-7) exerts direct effects on microglia, causing a reduction in both baseline and prorenin-induced release of proinflammatory cytokines. A compromised blood-brain barrier (BBB) constitutes a complementary mechanism that exacerbates AngII-driven neurohumoral activation, contributing to the development of hypertension.. PVN and BBB seem to be pivotal targets for therapeutic intervention in hypertension. Recent advances in imaging techniques enable visualization of the inflammatory state in microglia and BBB integrity in humans. AngII type I receptor blockers and AngII-converting enzyme inhibitors are the most likely candidates for controlled randomized trials in humans aimed at amelioration of brain inflammation in the forthcoming years.

Topics: Angiotensin I; Angiotensin II; Animals; Blood Pressure; Blood-Brain Barrier; Cytokines; Humans; Hypertension; Inflammation; Lipopolysaccharides; Microglia; NF-kappa B; Oxidative Stress; Paraventricular Hypothalamic Nucleus; Peptide Fragments; Renin; Toll-Like Receptor 4

Obstructive sleep apnea is associated with inflammation and oxidative stress in lung tissues and can lead to metabolic abnormalities. We investigated the effects of angiotensin1-7 [Ang-(1-7)] on lung injury in rats induced by chronic intermittent hypoxia (CIH). We randomly assigned 32 male Sprague-Dawley rats (180-200 g) to normoxia control (NC), CIH-untreated (uCIH), Ang-(1-7)-treated normoxia control (N-A), and Ang-(1-7)-treated CIH (CIH-A) groups. Oxidative stress biomarkers were measured in lung tissues, and expression of NADPH oxidase 4 (Nox4) and Nox subunits (p22phox, and p47phox) was determined by Western blot and reverse transcription-polymerase chain reaction. Pulmonary pathological changes were more evident in the uCIH group than in the other groups. Enzyme-linked immunosorbent assays and immunohistochemical staining showed that inflammatory factor concentrations in serum and lung tissues in the uCIH group were significantly higher than those in the NC and N-A groups. Expression of inflammatory factors was significantly higher in the CIH-A group than in the NC and N-A groups, but was lower than in the uCIH group (P<0.01). Oxidative stress was markedly higher in the uCIH group than in the NC and N-A groups. Expression of Nox4 and its subunits was also increased in the uCIH group. These changes were attenuated upon Ang-(1-7) treatment. In summary, treatment with Ang-(1-7) reversed signs of CIH-induced lung injury via inhibition of inflammation and oxidative stress.

Topics: Angiotensin I; Animals; Blotting, Western; Cytokines; Enzyme-Linked Immunosorbent Assay; Hypoxia; Immunohistochemistry; Inflammation; Lung; Lung Injury; Male; Malondialdehyde; Oxidative Stress; Peptide Fragments; Protective Agents; Random Allocation; Rats, Sprague-Dawley; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction; Sleep Apnea, Obstructive; Vasodilator Agents

Angiotensin-converting enzyme 2 (ACE2) is a counter-regulator against ACE by converting angiotensin II (Ang-II) to Ang-(1-7), but the effect of ACE2 and Ang-(1-7) on endothelial cell function and atherosclerotic evolution is unknown. We hypothesized that ACE2 overexpression and Ang-(1-7) may protect endothelial cell function by counterregulation of angiotensin II signaling and inhibition of inflammatory response.. We used a recombinant adenovirus vector to locally overexpress ACE2 gene (Ad-ACE2) in human endothelial cells in vitro and in apoE-deficient mice in vivo. The Ang II-induced MCP-1, VCAM-1 and E-selectin expression, endothelial cell migration and adhesion of human monocytic cells (U-937) to HUVECs by ACE2 gene transfer were evaluated in vitro. Accelerated atherosclerosis was studied in vivo, and atherosclerosis was induced in apoE-deficient mice which were divided randomly into four groups that received respectively a ACE2 gene transfer, Ad-ACE2, Ad-EGFP, Ad-ACE2 + A779, an Ang-(1-7) receptor antagonist, control group. After a gene transfer for 4 weeks, atherosclerotic pathology was evaluated.. ACE2 gene transfer not only promoted HUVECs migration, inhibited adhesion of monocyte to HUVECs and decreased Ang II-induced MCP-1, VCAM-1 and E-selectin protein production in vitro, but also decreased the level of MCP-1, VCAM-1 and interleukin 6 and inhibit atherosclerotic plaque evolution in vivo. Further, administration of A779 increased the level of MCP-1, VCAM-1 and interleukin 6 in vivo and led to further advancements in atherosclerotic extent.. ACE2 and Ang-(1-7) significantly inhibit early atherosclerotic lesion formation via protection of endothelial function and inhibition of inflammatory response.

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Apolipoproteins E; Atherosclerosis; Cell Adhesion; Cell Movement; Chemokine CCL2; Disease Models, Animal; E-Selectin; Endothelium, Vascular; Gene Transfer Techniques; Humans; In Vitro Techniques; Inflammation; Mice; Peptide Fragments; Peptidyl-Dipeptidase A; Signal Transduction; Vascular Cell Adhesion Molecule-1

The initiation or progression of periodontitis might involve a local renin-angiotensin system (RAS) in periodontal tissue. The aim of this study was to further characterize the local RAS in human and rat periodontal tissues between healthy and periodontally-affected tissue. Components of the RAS were investigated using in vitro, ex vivo and in vivo experiments involving both human and Wistar rat periodontium. Although not upregulated when challenged with P. gingivalis-lipopolysaccharide, human gingival and periodontal ligament fibroblasts expressed RAS components. Likewise, healthy and inflamed human gingiva expressed RAS components, some of which were shown to be functional, yet no differences in expression were found between healthy and diseased gingiva. However, in inflamed tissue the immunoreactivity was greater for the AT1R compared to AT2R in fibroblasts. When compared to healthy tissue, ACE activity was increased in human gingiva from volunteers with gingivitis. Human-gingiva homogenates generated Ang II, Ang 1-9 and Ang 1-7 when incubated with precursors. In gingiva homogenates, Ang II formation from Ang I was nearly abolished only when captopril and chymostatin were combined. Ang 1-7 formation was significantly greater when human gingiva homogenates were incubated with chymostatin alone compared to incubation without any inhibitor, only captopril, or captopril and chymostatin. In rat gingiva, RAS components were also found; their expression was not different between healthy and experimentally induced periodontitis (EP) groups. However, renin inhibition (aliskiren) and an AT1R antagonist (losartan) significantly blocked EP-alveolar-bone loss in rats. Collectively, these data are consistent with the hypothesis that a local RAS system is not only present but is also functional in both human and rat periodontal tissue. Furthermore, blocking AT1R and renin can significantly prevent periodontal bone loss induced by EP in rats.

Topics: Adult; Amino Acid Sequence; Angiotensin I; Angiotensin II; Animals; Cells, Cultured; Female; Gingiva; Humans; Inflammation; Male; Middle Aged; Peptide Fragments; Periodontitis; Periodontium; Rats, Wistar; Receptors, Angiotensin; Renin; Renin-Angiotensin System; Young Adult

The renin-angiotensin system (RAS) has been implicated in atherosclerotic lesions and progression to chronic kidney diseases. We examined regulatory roles of angiotensin-converting enzyme 2 (ACE2) in the apolipoprotein E (ApoE) knockout (KO) kidneys.. The 3-month-old wild-type, ApoEKO, ACE2KO and ApoE/ACE2 double-KO (DKO) mice in a C57BL/6 background were used. The ApoEKO mice were randomized to daily deliver either Ang II (1.5 mg/kg) and/or human recombinant ACE2 (rhACE2; 2 mg/kg) for 2 weeks. We examined changes in pro-inflammatory cytokines, renal ultrastructure, and pathological signaling in mouse kidneys.. Downregulation of ACE2 and nephrin levels was observed in ApoEKO kidneys. Genetic ACE2 deletion resulted in modest elevations in systolic blood pressure levels and Ang II type 1 receptor expression and reduced nephrin expression in kidneys of the ApoE/ACE2 DKO mice with a decrease in renal Ang-(1-7) levels. These changes were linked with marked increases in renal superoxide generation, NADPH oxidase (NOX) 4 and proinflammatory factors levels, including interleukin (IL)-1beta, IL-6, IL-17A, RANTES, ICAM-1, Tumor necrosis factor-alpha (TNF-alpha) and TNFRSF1A. Renal dysfunction and ultrastructure injury were aggravated in the ApoE/ACE2 DKO mice and Ang II-infused ApoEKO mice with increased plasma levels of creatinine, blood urea nitrogen and enhanced levels of Ang II in plasma and kidneys. The Ang II-mediated reductions of renal ACE2 and nephrin levels in ApoEKO mice were remarkably rescued by rhACE2 supplementation, along with augmentation of renal Ang-(1-7) levels. More importantly, rhACE2 treatment significantly reversed Ang II-induced renal inflammation, superoxide generation, kidney dysfunction and adverse renal injury in ApoEKO mice with suppression of the NOX4 and TNF-alpha-TNFRSF1A signaling. However, rhACE2 had no effect on renal NOX2 and TNFRSF1B expression and circulating lipid levels.. ACE2 deficiency exacerbates kidney inflammation, oxidative stress and adverse renal injury in the ApoE-mutant mice through modulation of the nephrin, NOX4 and TNF-alpha-TNFRSF1A signaling. While rhACE2 supplementation alleviates inflammation, renal dysfunction and glomerulus injury in the ApoE-mutant mice associated with upregulations of Ang-(1-7) levels and nephrin expression and suppression of the TNF-alpha-TNFRSF1A signaling. Strategies aimed at enhancing the ACE2/Ang-(1-7) actions may have important therapeutic potential for atherosclerotic renal injury and kidney diseases.

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Apolipoproteins E; Gene Deletion; Humans; Inflammation; Kidney; Male; Membrane Proteins; Mice, Inbred C57BL; Mice, Knockout; Models, Biological; NADPH Oxidase 4; NADPH Oxidases; Oxidative Stress; Peptide Fragments; Peptidyl-Dipeptidase A; Real-Time Polymerase Chain Reaction; Receptor, Angiotensin, Type 1; Receptors, Tumor Necrosis Factor, Type I; Recombinant Proteins; Signal Transduction; Superoxides; Tumor Necrosis Factor-alpha

The angiotensin converting enzyme 2-angiotensin-(1-7)-Mas axis (ACE2-Ang-(1-7)-Mas axis) is reported to participate in lipid metabolism in kidney, but its precise effects and underlying mechanisms remain unknown. We hypothesized that Ang-(1-7) reduces lipid accumulation and improves renal injury through the low density lipoprotein receptor-sterol regulatory element binding proteins 2-SREBP cleavage activating protein (LDLr-SREBP2-SCAP) system by suppressing inflammation in high fat diet (HFD)-fed mice. In this study, male C57BL/6 mice were randomized into four groups: STD (standard diet)+saline, HFD+saline, HFD+Ang-(1-7) and STD+Ang-(1-7). After 10 weeks of feeding, mice were administered Ang-(1-7) or saline for two weeks. We found that high inflammation status induced by HFD disrupted the LDLr-SREBP2-SCAP feedback system. Treatment of mice fed a high-fat diet with Ang-(1-7) induced significant improvement in inflammatory status, following the downregulation of LDLr, SREBP2 and SCAP, and then, decreased lipid deposition in kidney and improved renal injury. In conclusion, the anti-inflammatory effect of Ang-(1-7) alleviates renal injury triggered by lipid metabolic disorders through a LDLr- SREBP2-SCAP pathway.

Topics: Acute Kidney Injury; Angiotensin I; Animals; Anti-Inflammatory Agents; Diet, High-Fat; Dyslipidemias; Inflammation; Kidney; Lipid Metabolism; Male; Mice, Inbred C57BL; Peptide Fragments; Receptors, LDL; Signal Transduction; Sterol Regulatory Element Binding Protein 2

The angiotensin-converting enzyme 2 and angiotensin-(1-7) (Ang 1-7)/MasR (Mas receptor) axis are emerging as a key pathway that can modulate the development of diabetic cardiomyopathy. We studied the effects of Ang 1-7 on diabetic cardiomyopathy in db/db diabetic mice to elucidate the therapeutic effects and mechanism of action.. Ang 1-7 was administered to 5-month-old male db/db mice for 28 days via implanted micro-osmotic pumps. Ang 1-7 treatment ameliorated myocardial hypertrophy and fibrosis with normalization of diastolic dysfunction assessed by pressure-volume loop analysis and echocardiography. The functional improvement by Ang 1-7 was accompanied by a reduction in myocardial lipid accumulation and systemic fat mass and inflammation and increased insulin-stimulated myocardial glucose oxidation. Increased myocardial protein kinase C levels and loss of phosphorylation of extracellular signal-regulated kinase 1/2 were prevented by Ang 1-7. Furthermore, Ang 1-7 treatment decreased cardiac triacylglycerol and ceramide levels in db/db mice, concomitantly with an increase in myocardial adipose triglyceride lipase expression. Changes in adipose triglyceride lipase expression correlated with increased SIRT1 (silent mating type information regulation 2 homolog 1) levels and deacetylation of FOXO1 (forkhead box O1).. We identified a novel beneficial effect of Ang 1-7 on diabetic cardiomyopathy that involved a reduction in cardiac hypertrophy and lipotoxicity, adipose inflammation, and an upregulation of adipose triglyceride lipase. Ang 1-7 completely rescued the diastolic dysfunction in the db/db model. Ang 1-7 represents a promising therapy for diabetic cardiomyopathy associated with type 2 diabetes mellitus.

Topics: Angiotensin I; Animals; Blood Glucose; Diabetes Mellitus, Experimental; Diabetic Cardiomyopathies; Diastole; Echocardiography, Doppler; Follow-Up Studies; Inflammation; Insulin Resistance; Lipids; Male; Mice; Mice, Inbred C57BL; Peptide Fragments; Vasodilator Agents; Ventricular Dysfunction, Left; Ventricular Function; Ventricular Pressure

Angiotensin (Ang)-(1-7), acting through the receptor Mas, has atheroprotective effects; however, its role on plaque vulnerability has been poorly studied. Here, we investigated the expression of the renin-angiotensin system (RAS) components in stable and unstable human carotid plaques. In addition, we evaluated the effects of the chronic treatment with an oral formulation of Ang-(1-7) in a mouse model of shear stress-determined carotid atherosclerotic plaque. Upstream and downstream regions of internal carotid plaques were obtained from a recently published cohort of patients asymptomatic or symptomatic for ischaemic stroke. Angiotensinogen and renin genes were strongly expressed in the entire cohort, indicating an intense intraplaque modulation of the RAS. Intraplaque expression of the Mas receptor mRNA was increased in the downstream portion of asymptomatic patients as compared to corresponding region in symptomatic patients. Conversely, AT1 receptor gene expression was not modified between asymptomatic and symptomatic patients. Treatment with Ang-(1-7) in ApoE-/- mice was associated with increased intraplaque collagen content in the aortic root and low shear stress-induced carotid plaques, and a decreased MMP-9 content and neutrophil and macrophage infiltration. These beneficial effects were not observed in the oscillatory shear stress-induced plaque. In vitro incubation with Ang-(1-7) did not affect ICAM-1 expression and apoptosis on cultured endothelial cells. In conclusion, Mas receptor is up regulated in the downstream portions of human stable carotid plaques as compared to unstable lesions. Treatment with the oral formulation of Ang-(1-7) enhances a more stable phenotype in atherosclerotic plaques, depending on the local pattern of shear stress forces.

Topics: Administration, Oral; Angiotensin I; Animals; Anti-Inflammatory Agents; Apolipoproteins E; Carotid Arteries; Case-Control Studies; Disease Models, Animal; Humans; Inflammation; Mice; Mice, Inbred C57BL; Mice, Knockout; Peptide Fragments; Plaque, Atherosclerotic

Duchenne muscular dystrophy (DMD) is the most common inherited neuromuscular disease and is characterized by absence of the cytoskeletal protein dystrophin, muscle wasting, and fibrosis. We previously demonstrated that systemic infusion or oral administration of angiotensin-(1-7) (Ang-(1-7)), a peptide with opposing effects to angiotensin II, normalized skeletal muscle architecture, decreased local fibrosis, and improved muscle function in mdx mice, a dystrophic model for DMD. In this study, we investigated the presence, activity, and localization of ACE2, the enzyme responsible for Ang-(1-7) production, in wild type (wt) and mdx skeletal muscle and in a model of induced chronic damage in wt mice. All dystrophic muscles studied showed higher ACE2 activity than wt muscle. Immunolocalization studies indicated that ACE2 was localized mainly at the sarcolemma and, to a lesser extent, associated with interstitial cells. Similar results were observed in the model of chronic damage in the tibialis anterior (TA) muscle. Furthermore, we evaluated the effect of ACE2 overexpression in mdx TA muscle using an adenovirus containing human ACE2 sequence and showed that expression of ACE2 reduced the fibrosis associated with TA dystrophic muscles. Moreover, we observed fewer inflammatory cells infiltrating the mdx muscle. Finally, mdx gastrocnemius muscles from mice infused with Ang-(1-7), which decreases fibrosis, contain less ACE2 associated with the muscle. This is the first evidence supporting ACE2 as an important therapeutic target to improve the dystrophic skeletal muscle phenotype.

Topics: Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Cytoskeletal Proteins; Fibrosis; Humans; Inflammation; Mice; Mice, Inbred C57BL; Mice, Inbred mdx; Muscle Fibers, Skeletal; Muscular Dystrophy, Animal; Muscular Dystrophy, Duchenne; Peptide Fragments; Peptidyl-Dipeptidase A

Pulmonary fibrosis (PF) is a common complication in those interstitial lung diseases patients, which will result in poor prognosis and short survival. Traditional therapeutic methods such as glucocorticoid and cytotoxic drugs are insufficient for treating PF and may cause severe side effects. Recent studies showed that traditional Chinese herbal abstraction such as Tanshinone IIA (TIIA) was displayed significant anti-PF effects in animal models. However, the exact mechanisms underlying the protective effects of TIIA were not fully understood. Here we further investigated the protective effects of TIIA and its mechanisms underlying. PF models of rat were induced by bleomycin (BLM); TIIA was administered subsequently. The PF changes were identified by histopathological analyses. The results showed that BLM resulted in severe PF and alveolar inflammation; together with significant elevation of transforming growth factor-β 1 (TGF-β1). Angiotensin-converting enzyme 2 (ACE-2) together with angiotensin-(1-7) [ANG-(1-7)] were both greatly reduced after BLM administration. TIIA treatment notably attenuated BLM induced PF and inflammation, decreased expression of TGF-β1 and reversed ACE-2 and ANG-(1-7) production in rat lungs. Thus we may draw the conclusion that TIIA may exert protective effects on BLM induced PF in rats, and the ACE-2/ANG-(1-7) axis may ascribe to those protective effects.

Topics: Abietanes; Angiotensin I; Angiotensin-Converting Enzyme 2; Animals; Bleomycin; Humans; Inflammation; Peptide Fragments; Peptidyl-Dipeptidase A; Pulmonary Fibrosis; Rats; Transforming Growth Factor beta

Obesity is characterized by a pro-inflammatory state commonly associated with type 2 diabetes and fat-liver disease. In the last few years, different studies pointed out the role of Angiotensin (Ang)-(1-7) in the metabolic regulation. The aim of the present study was to evaluate the effect of oral-administration of Ang-(1-7) in metabolism and inflammatory state of high-fat feed rats. Twenty-four male Sprague Dawley rats were randomized into three groups: High Fat Diet (HFD); Standard Diet (ST); High Fat Diet+Angiotensin-(1-7) [HFD+Ang-(1-7)]. Glycemic profile was evaluated by glucose tolerance and insulin sensitivity tests, plasmatic glucose and insulin. Cholesterol, HDL and triglycerides analyses presented lipidic profile. RT-PCR evaluated mRNA expression to ACE, ACE2, resistin, TLR4, IL-6, TNF-α and NF-κB genes. The main results showed that oral Ang-(1-7) decreased body weight and abdominal fat-mass. In addition, HFD+Ang-(1-7) treated rats presented enhanced glucose tolerance, insulin-sensitivity and decreased plasma-insulin levels, as well as a significant decrease in circulating lipid levels. These alterations were accompanied by a marked decreased expression of resistin, TLR4, ACE and increased ACE2 expression in liver. Furthermore, Ang-(1-7) decreases phosphorylation of MAPK and increases NF-κB expression. These alterations diminished expression of interleukin-6 and TNF-α, ameliorate inflammatory state in liver. In summary, the present study showed that oral-treatment with Ang-(1-7) in high-fat feed rats improved metabolism down-regulating resistin/TLR4/NF-κB-pathway.

Topics: Angiotensin I; Animals; Blood Glucose; Cholesterol; Diet, High-Fat; Glucose Tolerance Test; Inflammation; Insulin; Insulin Resistance; Lipoproteins, HDL; Liver; Male; Mitogen-Activated Protein Kinases; NF-kappa B; Obesity; Peptide Fragments; Rats; Rats, Sprague-Dawley; Resistin; Toll-Like Receptor 4; Triglycerides

Angiotensin (Ang) II and its AT1 receptors have been implicated in the pathogenesis of rheumatoid arthritis. Activation of the counter-regulatory Ang-(1-7)-Mas receptor axis may contribute to some of the effects of AT₁ receptor blockers (ARBs). In this study, we have used losartan, an ARB, to investigate the role of and the mechanisms by which AT₁ receptors participated in two experimental models of arthritis: antigen-induced arthritis (AIA) in mice and adjuvant-induced arthritis (AdIA) in rats. Treatment with losartan decreased neutrophil recruitment, hypernociception and the production of TNF-α, IL-1β and chemokine (C-X-C motif) ligand 1 in mice subjected to AIA. Histopathological analysis showed significant reduction of tissue injury and inflammation and decreased proteoglycan loss. In addition to decreasing cytokine production, losartan directly reduced leukocyte rolling and adhesion. Anti-inflammatory effects of losartan were not associated to Mas receptor activation and/or Ang-(1-7) production. Anti-inflammatory effects were reproduced in rats subjected to AdIA. This study shows that ARBs have potent anti-inflammatory effects in animal models of arthritis. Mechanistically, reduction of leukocyte accumulation and of joint damage was associated with local inhibition of cytokine production and direct inhibition of leukocyte-endothelium interactions. The anti-inflammatory actions of losartan were accompanied by functional improvement of the joint, as seen by reduced joint hypernociception. These findings support the use of ARBs for the treatment of human arthritis and provide potential mechanisms for the anti-inflammatory actions of these compounds.

Topics: Angiotensin I; Angiotensin II Type 1 Receptor Blockers; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Experimental; Arthritis, Rheumatoid; Cell Adhesion; Chemokine CXCL1; Disease Models, Animal; Female; Hyperalgesia; Inflammation; Interleukin-1beta; Leukocyte Rolling; Losartan; Male; Mice; Mice, Inbred C57BL; Neutrophil Infiltration; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Rats; Rats, Sprague-Dawley; Receptor, Angiotensin, Type 1; Receptors, G-Protein-Coupled; Tumor Necrosis Factor-alpha

Angiotensin (Ang)-(1-7) has been described as an important tool on treating and preventing metabolic disorders. In this study, we aimed to evaluate the effect of an oral formulation of Ang-(1-7) included in hydroxypropylβ-cyclodextrin (HPβCD/Ang-[1-7]) on hepatic function, steatosis, and on liver inflammatory markers expression in mice treated with a high-fat diet. Male FVB/N mice were divided into 4 groups and fed for 60 days, with each group receiving 1 of the following diets: standard diet+HPβCD, standard diet+Ang-(1-7)/HPβCD, high-fat diet+HPβCD, or high-fat diet+Ang-[1-7]/HPβCD. Body weight, food intake, and blood parameters, such as total cholesterol, triglyceride, alaninetransaminases, and aspartate transaminases, were evaluated. Immunohistochemical analyses were performed for inflammatory markers tumor necrosis factor-α and interleukin-6. Expression of angiotensin converting enzyme, angiotensin-converting enzyme-2, interleukin-1β, tumor necrosis factor-α, interleukin-6, transforming growth factor-β, acetyl-CoA carboxylase, carbohydrate-responsive element-binding protein, peroxisome proliferator-activated receptor-γ, and sterol regulatory element-binding proteins-1c was evaluated by quantitative real-time polymerase chain reaction. The major findings of our study included reduced liver fat mass and weight, decreased plasma total cholesterol, triglyceride, and alaninetransaminase enzyme levels in the oral Ang-(1-7)-treated groups compared with the control groups. These results were accompanied by a significant reduction in tumor necrosis factor-α and interleukin-6 mRNA expression in the liver. Analyses of liver adipogenesis-related genes by quantitative real-time polymerase chain reaction showed that acetyl-CoA carboxylase, peroxisome proliferator-activated receptor-γ, and sterol regulatory element-binding proteins-1c mRNA expression were significantly suppressed. In conclusion, we observed that treatment with Ang-(1-7) improved metabolism and decreased proinflammatory profile and fat deposition in liver of mice.

Topics: Administration, Oral; Angiotensin I; Animals; Chemistry, Pharmaceutical; Diet, High-Fat; Fatty Liver; Inflammation; Interleukin-6; Lipid Metabolism; Male; Mice; Peptide Fragments; Sterol Regulatory Element Binding Protein 1; Tumor Necrosis Factor-alpha

About 500,000 new cancer patients will develop brain metastases in 2013. The primary treatment modality for these patients is partial or whole brain irradiation which leads to a progressive, irreversible cognitive impairment. Although the exact mechanisms behind this radiation-induced brain injury are unknown, neuroinflammation in glial populations is hypothesized to play a role. Blockers of the renin-angiotensin system (RAS) prevent radiation-induced cognitive impairment and modulate radiation-induced neuroinflammation. Recent studies suggest that RAS blockers may reduce inflammation by increasing endogenous concentrations of the anti-inflammatory heptapeptide angiotensin-(1-7) [Ang-(1-7)]. Ang-(1-7) binds to the AT(1-7) receptor and inhibits MAP kinase activity to prevent inflammation. This study describes the inflammatory response to radiation in astrocytes characterized by radiation-induced increases in (i) IL-1β and IL-6 gene expression; (ii) COX-2 and GFAP immunoreactivity; (iii) activation of AP-1 and NF-κB transcription factors; and (iv) PKCα, MEK, and ERK (MAP kinase) activation. Treatment with U-0126, a MEK inhibitor, demonstrates that this radiation-induced inflammation in astrocytes is mediated through the MAP kinase pathway. Ang-(1-7) inhibits radiation-induced inflammation, increases in PKCα, and MAP kinase pathway activation (phosphorylation of MEK and ERK). Additionally Ang-(1-7) treatment leads to an increase in dual specificity phosphatase 1 (DUSP1). Furthermore, treatment with sodium vanadate (Na3VO4), a phosphatase inhibitor, blocks Ang-(1-7) inhibition of radiation-induced inflammation and MAP kinase activation, suggesting that Ang-(1-7) alters phosphatase activity to inhibit radiation-induced inflammation. These data suggest that RAS blockers inhibit radiation-induced inflammation and prevent radiation-induced cognitive impairment not only by reducing Ang II but also by increasing Ang-(1-7) levels.

Topics: Angiotensin I; Animals; Astrocytes; Cells, Cultured; Drug Evaluation, Preclinical; Dual Specificity Phosphatase 1; Inflammation; MAP Kinase Signaling System; Peptide Fragments; Primary Cell Culture; Radiation-Protective Agents; Rats

Endothelial dysfunction plays an important role in all stages of atherosclerosis and is characterized by an increased proinflammatory response. This study investigated the effect of angiotensin (1-7) on angiotensin II (Ang II)-mediated inflammation in endothelial cells (ECs) and uncovered its molecular mechanism.. Real-time PCR and western blot analysis were used to determine lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) expression. Ang II treatment induced inflammation, as measured by the production of vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1, by activating nuclear factor-κB (NF-κB) in ECs. Ang II also induced LOX-1 expression in human ECs and rabbit aortic ECs. LOX-1 played an essential role in Ang II-mediated inflammation because Ang II antagonists or small interference RNA significantly decreased Ang II-induced VCAM-1 production. LOX-1 overexpression enhanced Ang II-mediated inflammation. LOX-1 mediated Ang II-induced inflammation by inducing NF-κB DNA-binding activity. Angiotensin (1-7) inhibited LOX-1 expression and diminished Ang II-mediated inflammation in ECs.. Our findings suggest that angiotensin (1-7) prevents Ang II-induced inflammation by inhibiting LOX-1 mRNA and protein expression in ECs and may represent a novel pleiotropic effect of angiotensin (1-7).

Topics: Angiotensin I; Angiotensin II; Animals; Cell Adhesion; Chemokine CCL2; DNA; Endothelial Cells; Female; Humans; Inflammation; Male; NF-kappa B; Peptide Fragments; Rabbits; Scavenger Receptors, Class E; Vascular Cell Adhesion Molecule-1

Angiotensin-converting enzyme 2 (ACE-2) is a membrane-associated carboxy-peptidase catalyzes the conversion of the vasoconstrictor angiotensin (ANG)-II to the vasodilatory peptide ANG 1-7. In view of the expanding axis of the renin angiotensin system, we have investigated the cardioprotective effects of olmesartan (10mg/kg/day) in experimental autoimmune myocarditis. Olmesartan treatment effectively suppressed the myocardial protein expressions of inflammatory markers in comparison to the vehicle-treated rats. However, the protein and mRNA levels of ACE-2 and ANG 1-7, and its receptor Mas were upregulated in olmesartan treated group compared to vehicle-treated rats. Olmesartan medoxomil treatment significantly decreased the expression levels of phospho-p38 mitogen-activated protein kinase (MAPK), phospho-JNK, phospho-ERK and phospho-(MAPK) activated protein kinase-2 than with those of vehicle-treated rats. Moreover, vehicle-treated rats were shown to be up-regulated protein expressions of NADPH oxidase subunits (p47phox, p67phox and Nox-4), myocardial apoptotic markers and endoplasmic reticulum stress markers in comparison to those of normal and all these effects are expectedly down-regulated by an olmesartan. In addition, attenuated protein levels of phosphatidylinositol-3-kinase (PI3K) and phospho-Akt in the vehicle-treated EAM rats were prevented by olmesartan treatment. Our results suggest that beneficial effects of olmesartan treatment was more effective therapy in combating the inflammation, oxidative stress, apoptosis and signaling pathways associated with heart failure at least in part via the modulation of ANG 1-7 mas receptor.

Topics: Angiotensin I; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme 2; Animals; Apoptosis; Autoimmune Diseases; Cardiotonic Agents; Endoplasmic Reticulum Stress; Heart Failure; Imidazoles; Inflammation; JNK Mitogen-Activated Protein Kinases; Membrane Glycoproteins; Myocarditis; NADPH Oxidase 4; NADPH Oxidases; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Peptide Fragments; Peptidyl-Dipeptidase A; Phosphatidylinositol 3-Kinases; Phosphoproteins; Proto-Oncogene Proteins c-akt; Rats; Rats, Inbred Lew; Receptor, Angiotensin, Type 1; Receptors, Interleukin-1; RNA, Messenger; Tetrazoles

The aim of the present study was to evaluate the effect of a transgenic-induced chronic increase of Ang-(1-7) on the expression of inflammatory markers in adipose tissue and the metabolic profile in rats treated with high-fat diet.. Transgenic rats expressing an Ang-(1-7)-producing fusion protein (TGR L-3292) and Sprague Dawley (SD) control rats 4 weeks old were treated for 8 weeks with a high-fat diet. Food intake and body weight were measured once a week. Glucose-tolerance and insulin sensitivity tests were performed one week before the sacrifice. At the end of the experiment plasma lipid concentrations were measured in TGR and SD rats. Adipose tissue were weighted and corrected by the body weight. Proinflammatory markers in adipose tissue were analyzed using Western-blotting, real time-PCR and immunohistochemistry.. High-fat diet TGR rats presented increased HDL cholesterol levels and decreased abdominal fat mass, without changes in food intake. In addition, rats with increased Ang-(1-7) levels had lower body weight. Molecular analysis revealed decreased IL-1β and COX-2 in adipose tissue.. Taken together, these results show that chronic high circulating angiotensin-(1-7) levels protect against metabolic stress induced by a high-fat diet decreasing the proinflammatory profile of adipose tissue.

Topics: Adipokines; Adiposity; Angiotensin I; Animals; Blood Glucose; Cholesterol, HDL; Diet, High-Fat; Epididymis; Inflammation; Inflammation Mediators; Interleukin-1beta; Intra-Abdominal Fat; Male; Obesity; Oxidative Stress; Peptide Fragments; Rats; Rats, Sprague-Dawley; Rats, Transgenic; Tumor Necrosis Factor-alpha

Angiotensin-(1-7) [Ang-(1-7)] has anti-inflammatory effects in peripheral organs, but its effects in ischaemic stroke are unclear as yet. We investigated whether its anti-inflammatory effect contributes to the neuroprotection induced by Ang-(1-7) in a rat model of permanent middle cerebral artery occlusion (pMCAO).. We infused Ang-(1-7), Mas receptor antagonist A-779, angiotensin II type 2 receptor antagonist PD123319 or artificial CSF into the right lateral ventricle of male Sprague-Dawley rats from 48 h before onset of pMCAO until the rats were killed. Twenty-four hours after pMCAO, the neuroprotective effect of Ang-(1-7) was analysed by evaluating infarct volume and neurological deficits. The levels of oxidative stress were detected by spectrophotometric assay. The activation of NF-κB was assessed by Western blot and immunohistochemistry analysis. The level of COX-2 was tested by Western blot analysis and concentrations of pro-inflammatory cytokines were measured by elisa.. Infusion of Ang-(1-7), i.c.v., significantly reduced infarct volume and improved neurological deficits. It decreased the levels of oxidative stress and suppressed NF-κB activity, which was accompanied by a reduction of pro-inflammatory cytokines and COX-2 in the peri-infarct regions. These effects of Ang-(1-7) were reversed by A-779 but not by PD123319. Additionally, infusion of A-779 alone increased oxidative stress levels and enhanced NF-κB activity, which was accompanied by an up-regulation of pro-inflammatory cytokines and COX-2.. Our findings indicate that suppressing NF-κB dependent pathway via Mas receptor may represent one mechanism that contributes to the anti-inflammatory effects of Ang-(1-7) in rats with pMCAO.

Topics: Angiotensin I; Angiotensin II; Angiotensin II Type 2 Receptor Blockers; Animals; Anti-Inflammatory Agents; Behavior, Animal; Cerebrovascular Circulation; Imidazoles; Infarction, Middle Cerebral Artery; Inflammation; Male; Neuroprotective Agents; NF-kappa B; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Pyridines; Rats; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled

Reduced alveolar Po(2) in rats produces a rapid systemic inflammation characterized by reactive O(2) species generation, mast cell (MC) degranulation, leukocyte-endothelial interactions, and increased vascular permeability. The inflammation is not initiated by the low systemic Po(2) but rather by the release of monocyte chemoattractant protein-1 (MCP-1) from alveolar macrophages (AMO) activated by alveolar hypoxia. Circulating AMO-borne MCP-1 induces MC degranulation, which activates the local renin-angiotensin system (RAS) and mediates the microvascular inflammation. This study was directed to determine the mechanism of RAS activation by MCP-1-induced MC degranulation. Experiments in isolated rat peritoneal MCs showed the following: 1) Western blots and immunocytochemistry demonstrated the presence of renin and angiotensin-converting enzyme (ACE) in MCs and their release upon degranulation; 2) MCP-1-induced degranulation of MCs incubated in plasma produced an increase in angiotensin II (ANG II) concentration; and 3) this increase was inhibited completely by the following agents: the MCP-1 receptor antagonist RS-102895, the specific rat renin inhibitor WFML, or the ACE inhibitor captopril administered separately. Captopril also inhibited ANG II generation by MCs incubated in culture medium plus ANG I. The results show that peritoneal MCs contain active renin, which activates the RAS upon degranulation, and that peritoneal MCs are a source of ACE and suggest that conversion of ANG I to ANG II is mediated predominantly by ACE. This study provides novel evidence of the presence of active renin in rat peritoneal MCs and helps explain the mechanism of activation of the RAS during alveolar hypoxia.

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Blotting, Western; Cell Degranulation; Cells, Cultured; Chemokine CCL2; Hypoxia; Immunohistochemistry; Inflammation; Macrophage Activation; Macrophages, Peritoneal; Peptidyl-Dipeptidase A; Pulmonary Alveoli; Rats; Rats, Sprague-Dawley; Receptors, CCR2; Renin; Renin-Angiotensin System

The potential regulatory effect of angiotensins on circulating mononuclear cell activation and migration has not yet been thoroughly evaluated. Using flow cytometry we assessed the possible effect of angiotensin I and II on the expression of CX3CR1 and a single representative of each major chemokine family (CCR5 and CXCR4) in THP-1 monocytes, Jurcat T lymphocytes and primary monocytes-isolated from healthy donors. Fluorescence intensity and the rate of chemokine-positive cells was measured in naïve cells and cells treated with angiotensin I and II. Neither angiotensin I nor angiotensin II exhibited any effect on fluorescence intensity and the rate of CX3CR1-, CCR5- and CXCR4-positive cells in primary peripheral blood mononuclear cells and Jurkat T cells. However, angiotensin II significantly increased the rate of CX3CR1-positive THP-1 cells. This effect was not attenuated by the pre-incubation of THP-1 cells with the AT-1 receptor blocker losartan, suggesting that this was not an AT-1-mediated effect. Angiotensin I and II had no effect on fluorescence intensity and the rate of CCR5- and CXCR4-positive THP-1 cells. In conclusion, angiotensin II increases the rate of CX3CR1-positive THP-1 cells. By extrapolating this in vitro observation to disease mechanisms, we speculate that angiotensin II induces up-regulation of CX3CR1 and promotes firm adhesion of circulation CX3CR1-positive monocytes on CX3CL1 expressing endothelial cells inducing vascular inflammation and atherogenesis.

Topics: Angiotensin I; Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Atherosclerosis; Cell Adhesion; Cell Movement; Chemokine CX3CL1; CX3C Chemokine Receptor 1; Endothelial Cells; Gene Expression Regulation; Humans; Inflammation; Jurkat Cells; Losartan; Monocytes; Receptors, CCR5; Receptors, Chemokine; Receptors, CXCR4; Vasculitis; Vasoconstrictor Agents

Angiotensin (Ang) II mediates pathophysiologial changes in the kidney. Ang-(1-7) by interacting with the G protein-coupled receptor Mas may also have important biological activities.In this study, renal deficiency for Mas diminished renal damage in models of renal insufficiency as unilateral ureteral obstruction and ischemia/reperfusion injury while the infusion of Ang-(1-7) to wild-type mice pronounced the pathological outcome by aggravating the inflammatory response. Mas deficiency inhibited NF-kappaB activation and thus the elevation of inflammation-stimulating cytokines, while Ang-(1-7) infusion had proinflammatory properties in experimental models of renal failure as well as under basal conditions. The Ang-(1-7)-mediated NF-kappaB activation was Mas dependent but did not involve Ang II receptors. Therefore, the blockade of the NF-kappaB-activating properties of the receptor Mas could be a new strategy in the therapy of failing kidney.

Topics: Angiotensin I; Animals; Antihypertensive Agents; Cytokines; Inflammation; Kidney Diseases; Mice; Mice, Knockout; NF-kappa B; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Receptors, G-Protein-Coupled; Reperfusion Injury

A change in the microcirculatory hemodynamic is one of the most important events in inflammation. In the dental pulp, which is a connective tissue surrounded by a mineralized dentine substrate, disturbance in the blood flow as well as plasma extravasation may increase the pulp pressure and cause local ischemia. The octapeptide angiotensin II (AngII) regulates vascular tone and stimulates the release of pro-inflammatory cytokines by acting through the AT1 and AT2 receptors. The AT1 receptor is responsible for the classical effects of AngII. The AT2 receptor is involved in other effects, such as vasodilation. Therefore, we aimed to evaluate the role of AT1 and AT2 receptors on the pulpal inflammation. The pulp tissue was mechanically exposed and after different periods the teeth were extracted and submitted to histopathological and RT-PCR analyses. The histological sections showed a number of congested and dilated blood vessels associated with a notable presence of inflammatory cells. RT-PCR data revealed that the AT1 receptor was down-regulated at 24 h after the pulp exposure. The AT2 receptor expression was up-regulated by a 9-hour period, and then decreased between 12- and 24-hour periods. It was demonstrated that the renin-angiotensin system plays an important role in the pulpal inflammation, with regulation of AngII receptor levels.

Topics: Angiotensin I; Angiotensin II; Animals; Dental Pulp; Inflammation; Male; Pulpitis; Rats; Rats, Wistar; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors

We investigate the influence of des-Aspartate-angiotensin-I (DAA-I) on the cytokine expression profile in a rodent model of myocardial infarction. Myocardial infarction model was created in female Wistar rats by coronary artery ligation. Animals were randomized to receive intravenously either a daily dose of 1.2 mug DAA-I/kg body weight (group 1; n = 60) or saline (group 2; n = 60) for 14 days after infarction. Heart function was assessed by echocardiography. Animals were euthanized at 1, 3, 7, 14 and 31 days. Morphometric analysis using tetrazolium chloride staining revealed that infarct size was reduced by 32.2% (p < 0.05) in group 1 after 14 days of DAA-I treatment. Left ventricular ejection fraction in group 1 improved significantly (73.4%) as compared to group 2 (47.7%; p < 0.001). Immunostaining for immune cells at the infarct site showed that CD8+ lymphocytes infiltration at the infarct site declined in group 1 (15 +/- 5 cells) as compared to group 2 (50 +/- 6 cells; p < 0.001). Infiltration of monocytes and macrophages remained high at day 14 in group 2 (126 +/- 40 cells) as compared to group 1 (49 +/- 11 cells; p = 0.006). Multiplex PCR was done for differential gene expression of various pro-inflammatory cytokines. IL-6, TNF-alpha, TGF-beta and GM-CSF expression were significantly down-regulated in the infarct, peri-infarct and contra-lateral zones of the left ventricle in group 1 as compared to group 2. IL-6, TGF-beta and GM-CSF expression started to decline from day 1 of DAA-I treatment while TNF-alpha expression only reduced after 7 days of DAA-I treatment. We conclude that DAA-I prevented infarct expansion through suppression of inflammatory cytokines and immune cell infiltration in the infarct region.

Topics: Angiotensin I; Animals; Cardiotonic Agents; Cytokines; Disease Models, Animal; DNA Primers; Echocardiography; Female; Gene Expression Profiling; Gene Expression Regulation; Granulocyte-Macrophage Colony-Stimulating Factor; Inflammation; Myocardial Infarction; Rats; Rats, Wistar; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Cathepsin G, elastase, and proteinase 3 are serine proteinases released by activated neutrophils. Cathepsin G can cleave angiotensinogen to release angiotensin II, but this activity has not been previously reported for elastase or proteinase 3. In this study we show that elastase and proteinase 3 can release angiotensin I from angiotensinogen and release angiotensin II from angiotensin I and angiotensinogen. The relative order of potency in releasing angiotensin II by the three proteinases at equivalent concentrations is cathepsin G > elastase > proteinase 3. When all three proteinases are used together, the release of angiotensin II is greater than the sum of the release when each proteinase is used individually. Cathepsin G and elastase can also degrade angiotensin II, reactions which might be important in regulating the activity of angiotensin II. The release and degradation of angiotensin II by the neutrophil proteinases are reactions which could play a role in the local inflammatory response and wound healing.

Topics: Angiotensin I; Angiotensin II; Angiotensinogen; Binding Sites; Cathepsin G; Cathepsins; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Humans; Inflammation; Models, Biological; Myeloblastin; Neutrophils; Pancreatic Elastase; Protein Binding; Serine Endopeptidases; Time Factors; Wound Healing

To investigate the effect of angiotensin (Ang) II type 1 receptor (AT(1)) blocker on vascular remodeling and explore the possibility of the involvement of Ang II type 2 receptor (AT(2)) stimulation in this process, we examined the effects of the selective AT(1) blocker valsartan on the vascular injury in wild-type (Agtr2+) and AT(2)-null (Agtr2-) mice.. Neointima formation and the proliferation of vascular smooth muscle cells (VSMCs) induced by cuff placement on the femoral artery were greater in Agtr2- mice than those in Agtr2+ mice. Treatment of mice with valsartan at a dose of 1 mg. kg(-1). d(-1), which did not influence systolic blood pressure, significantly decreased neointima formation and the proliferation of VSMCs, whereas the valsartan was less effective in Agtr2- mice. Moreover, cuff placement increased the expression of monocyte chemoattractant protein-1 (MCP-1); inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-1beta; and infiltration of CD45-positive leukocytes and macrophages in the injured arteries and further enhanced them in Agtr2- mice, suggesting the antagonistic effects of AT(1) and AT(2) for vascular inflammation. Valsartan attenuated the expression of MCP-1, TNF-alpha, IL-6, IL-1beta, and infiltration of leukocytes and macrophages in the injured arteries; however, these effects of valsartan were less prominent in Agtr2- mice.. These results suggest that the stimulation of the AT(2) receptor after AT(1) blockade is important in the improvement of the inflammatory vascular injury.

Topics: Angiotensin I; Angiotensin II; Angiotensin Receptor Antagonists; Animals; Antihypertensive Agents; Blood Pressure; Cell Division; Chemokine CCL2; Femoral Artery; Inflammation; Interleukin-1; Interleukin-6; Leukocyte Common Antigens; Leukocytes; Macrophages; Male; Mice; Mice, Knockout; Muscle, Smooth, Vascular; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; RNA, Messenger; Tetrazoles; Tumor Necrosis Factor-alpha; Tunica Intima; Valine; Valsartan

Angiotensinogen is the precursor of biologically active peptide angiotensin II and its hepatic synthesis is increased by the induction of acute inflammation. Studies were carried out to know whether the rise in plasma angiotensinogen is actually involved in the activity of the renin-angiotensin system during acute inflammation. The plasma level of angiotensinogen in rats was increased to 2.5 times the normal level 16 h after the induction of acute inflammation by administration of lipopolysaccharide (LPS). The plasma renin concentration (PRC) was decreased to about 40% of the normal level concomitantly with a reduction of plasma renin activity (PRA) at 4 h after LPS administration. In contrast, 16 h after LPS injection, when plasma angiotensinogen showed a high level and PRC had recovered to the normal range, PRA was increased to 1.7 times the normal level. These results indicate that acute inflammation induced by LPS causes a biphasic change in the generation of angiotensin I, i.e., an early decrease depending upon the reduction of PRC and later increase depending upon elevation of the angiotensinogen concentration.

Topics: Acute Disease; Angiotensin I; Angiotensinogen; Animals; Inflammation; Lipopolysaccharides; Male; Rats; Rats, Inbred F344; Renin; Renin-Angiotensin System