resolvin-d2 and Inflammation

Non-resolving inflammation is an underpinning of cardiovascular diseases including atherosclerosis. The resolution of inflammation is an active and highly coordinated process that involves the generation of specialized pro-resolving mediators (SPMs), and other factors including proteins, gases, and nucleotides. SPMs comprise a superfamily of lipid mediators that includes lipoxins, resolvins, maresins and protectins. SPMs act through distinct G protein-coupled receptors (GPCRs) and have been extensively studied in animal models of cardiovascular diseases. An emerging body of literature suggests that SPMs have protective roles in atherosclerosis as demonstrated using specific SPM as well as mice deficient in their receptors. This review will highlight a relatively new pro-resolving signaling axis, namely Resolvin D2-GPR18, and how understanding detailed mechanisms and cellular specificity of this signaling axis may help inform the development of more targeted pro-resolution therapies for atherosclerosis and related cardiovascular pathologies.

Topics: Animals; Atherosclerosis; Cardiovascular Diseases; Cardiovascular Physiological Phenomena; Humans; Inflammation; Inflammation Mediators; Mice; Receptors, G-Protein-Coupled

Accumulating evidence suggests that inflammation plays an important role in the pathophysiology of the initiation and progression of cardiovascular and metabolic diseases (CVMDs). Anti-inflammation strategies and those that promote inflammation resolution have gradually become potential therapeutic approaches for CVMDs. Resolvin D2 (RvD2), a specialized pro-resolving mediator, exerts anti-inflammatory and pro-resolution effects through its receptor GPR18, a G protein-coupled receptor. Recently, the RvD2/GPR18 axis has received more attention due to its protective role in CVMDs, including atherosclerosis, hypertension, ischaemiareperfusion, and diabetes. Here, we introduce basic information about RvD2 and GPR18, summarize their roles in different immune cells, and review the therapeutic potential of the RvD2/GPR18 axis in CVMDs. In summary, RvD2 and its receptor GPR18 play an important role in the occurrence and development of CVMDs and are potential biomarkers and therapeutic targets.

Topics: Anti-Inflammatory Agents; Biomarkers; Cardiovascular Diseases; Docosahexaenoic Acids; Humans; Inflammation; Metabolic Diseases; Receptors, G-Protein-Coupled

The high incidence of cardiovascular disease (CVD) in chronic kidney disease (CKD) is related partially to chronic inflammation. n-3 Fatty acids have been shown to have anti-inflammatory effects and to reduce the risk of CVD. Specialized Proresolving Lipid Mediators (SPMs) derived from the n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) actively promote the resolution of inflammation. This study evaluates the effects of n-3 fatty acid supplementation on plasma SPMs in patients with CKD.. In a double-blind, placebo-controlled intervention of factorial design, 85 patients were randomized to either n-3 fatty acids (4 g), Coenzyme Q10 (CoQ) (200 mg), both supplements, or control (4 g olive oil), daily for 8 weeks. The SPMs 18-HEPE, 17-HDHA, RvD1, 17R-RvD1, and RvD2, were measured in plasma by liquid chromatography-tandem mass spectrometry before and after intervention.. Seventy four patients completed the 8 weeks intervention. n-3 Fatty acids but not CoQ significantly increased (P < 0.0001) plasma levels of 18-HEPE and 17-HDHA, the upstream precursors to the E- and D-series resolvins, respectively. RvD1 was significantly increased (P = 0.036) after n-3 fatty acids, but no change was seen in other SPMs. In regression analysis the increase in 18-HEPE and 17-HDHA after n-3 fatty acids was significantly predicted by the change in platelet EPA and DHA, respectively.. SPMs are increased after 8 weeks n-3 fatty acid supplementation in patients with CKD. This may have important implications for limiting ongoing low grade inflammation in CKD.

Topics: Adult; Aged; Anti-Inflammatory Agents, Non-Steroidal; Blood Glucose; Body Mass Index; C-Reactive Protein; Dietary Supplements; Docosahexaenoic Acids; Double-Blind Method; Eicosapentaenoic Acid; Female; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Insulin; Male; Middle Aged; Renal Insufficiency, Chronic

Eosinophils (Eos) reside in multiple organs during homeostasis and respond rapidly to an inflammatory challenge. Although Eos share chemical staining properties, they also demonstrate phenotypic and functional plasticity that is not fully understood. Here, we used a murine model of allergic lung inflammation to characterize Eos subsets and determine their spatiotemporal and functional regulation during inflammation and its resolution in response to resolvin D2 (RvD2), a potent specialized proresolving mediator. Two Eos subsets were identified by CD101 expression with distinct anatomic localization and transcriptional signatures at baseline and during inflammation. CD101

Topics: Alveolitis, Extrinsic Allergic; Animals; Bronchoalveolar Lavage Fluid; Eosinophils; Inflammation; Mice; Phenotype; Pneumonia; Pulmonary Eosinophilia

Chronic inflammation in atherosclerosis reflects a failure in the resolution of inflammation. Pro-resolving lipid mediators derived from omega-3 fatty acids reduce the development of atherosclerosis in murine models. The aim of the present study was to decipher the role of the specialized proresolving mediator (SPM) resolvin D2 (RvD2) in atherosclerosis and its signaling through the G-protein coupled receptor (GPR) 18. The ligand and receptor were detected in human coronary arteries in relation to the presence of atherosclerotic lesions and its cellular components. Importantly, RvD2 levels were significantly higher in atherosclerotic compared with healthy human coronary arteries. Furthermore, apolipoprotein E (ApoE) deficient hyperlipidemic mice were treated with either RvD2 or vehicle in the absence and presence of the GPR18 antagonist O-1918. RvD2 significantly reduced atherosclerosis, necrotic core area, and pro-inflammatory macrophage marker expression. RvD2 in addition enhanced macrophage phagocytosis. The beneficial effects of RvD2 were not observed in the presence of O-1918. Taken together, these results provide evidence of atheroprotective pro-resolving signalling through the RvD2-GPR18 axis.

Topics: Animals; Apolipoproteins E; Atherosclerosis; Coronary Artery Disease; Docosahexaenoic Acids; Humans; Inflammation; Mice; Receptors, G-Protein-Coupled; Signal Transduction

Inflammation plays an important role in diabetes mellitus (DM)-related acute ischemic stroke (AIS). The mechanisms of un-resolved inflammation in DM-related AIS are not fully understood. Specialized pro-resolving mediators (SPMs) are key regulators that promote resolution of inflammation. We aimed to examine resolution function in patients with AIS complicated with DM, and explore potential treatment effects of one of the SPMs, resolvin D2 (RvD2) ex vivo and in vivo.. Cultured human macrophages, which were derived from peripheral blood mononuclear cells of AIS and none-AIS patients with or without DM, were stimulated with oxidized-low density lipoprotein (ox-LDL). Levels of SPMs and inflammatory markers were analysed, and RvD2 treatment effects were evaluated in these cells. For experiments in vivo, challenges with high fat diet and low-dose streptozotocin (STZ) were used to induce DM in C57BL/6J mice. AIS model was established by permanent middle cerebral artery occlusion (pMCAO) followed by intra-cerebroventricular injection of RvD2.. Our data demonstrate resolution of inflammation is impaired by DM in AIS patients, implicating a novel mechanism of un-resolved inflammation in DM-related AIS. Furthermore, RvD2 promotes inflammation resolution in macrophages/microglia and protects DM-related AIS, and may thus serve as a novel therapeutic target.

Topics: Animals; Diabetes Mellitus; Docosahexaenoic Acids; Humans; Infarction, Middle Cerebral Artery; Inflammation; Ischemic Stroke; Leukocytes, Mononuclear; Mice; Mice, Inbred C57BL

Resolvins (RvD1, RvD2 and RvE1) are endogenous anti-inflammatory lipid mediators that display potent analgesic properties in somatic pain by modulating transient receptor potential vanilloid 1 (TRPV1) activation. To what extent these molecules could also have a beneficial effect on TRPV1 sensitisation and visceral hypersensitivity (VHS), mechanisms involved in IBS, remains unknown.. The effect of RvD1, RvD2 and RvE1 on TRPV1 activation and sensitisation by histamine or IBS supernatants was assessed on murine dorsal root ganglion (DRG) neurons using live Ca. RvD1, RvD2 and RvE1 prevented histamine-induced TRPV1 sensitisation in DRG neurons at doses devoid of an analgesic effect. Of note, RvD2 also reversed TRPV1 sensitisation by histamine and IBS supernatant. This effect was blocked by the G protein receptor 18 (GPR18) antagonist O-1918 (3-30 µM) and by pertussis toxin. In addition, RvD2 reduced the capsaicin-induced Ca. Our data suggest that RvD2 and GPR18 agonists may represent interesting novel compounds to be further evaluated as treatment for IBS.

Topics: Adult; Animals; Capsaicin; Disease Models, Animal; Docosahexaenoic Acids; Eicosapentaenoic Acid; Enterobacteriaceae Infections; Female; Ganglia, Spinal; Histamine; Humans; Hypersensitivity; Inflammation; Irritable Bowel Syndrome; Male; Mice; Middle Aged; Neurons; Rats; Receptors, Cannabinoid; TRPV Cation Channels

An excessive, non-resolving inflammatory response underlies severe COVID-19 that may have fatal outcomes. Therefore, the investigation of endogenous pathways leading to resolution of inflammation is of interest to uncover strategies for mitigating inflammation in people with SARS-CoV-2 infection. This becomes particularly urgent in individuals with preexisting pathologies characterized by chronic respiratory inflammation and prone to bacterial infection, such as cystic fibrosis (CF). Here, we analyzed the immune responses to SARS-CoV-2 virion spike 1 glycoprotein (S1) of macrophages (MΦ) from volunteers with and without CF and tested the efficacy of resolvins (Rv) D1 and D2 in regulating the inflammatory and antimicrobial functions of MΦ exposed to S1. S1 significantly increased chemokine release, including interleukin (IL)-8, in CF and non-CF MΦ, while it enhanced IL-6 and tumor necrosis factor (TNF)-α in non-CF MΦ, but not in CF cells. S1 also triggered the biosynthesis of RvD1 and modulated microRNAs miR-16, miR-29a, and miR-103, known to control the inflammatory responses. RvD1 and RvD2 treatment abated S1-induced inflammatory responses in CF and non-CF MΦ, significantly reducing the release of select chemokines and cytokines including IL-8 and TNF-α. RvD1 and RvD2 both restored the expression of miR-16 and miR-29a, while selectively increasing miR-223 and miR-125a, which are involved in NF-κB activation and MΦ inflammatory polarization. During Pseudomonas aeruginosa infection, S1 stimulated the MΦ phagocytic activity that was further enhanced by RvD1 and RvD2. These results provide a map of molecular responses to SARS-CoV-2 in MΦ, key determinants of COVID-19-related inflammation, unveiling some peculiarity in the response of cells from individuals with CF. They also demonstrate beneficial, regulatory actions of RvD1 and RvD2 on SARS-CoV-2-induced inflammation.

Topics: COVID-19; Cystic Fibrosis; Cytokines; Docosahexaenoic Acids; Female; Gene Expression Regulation; Humans; Inflammation; Macrophages; Male; MicroRNAs; Pseudomonas aeruginosa; Pseudomonas Infections; SARS-CoV-2; Spike Glycoprotein, Coronavirus

The prototypic proinflammatory cytokine IL-1β plays a central role in innate immunity and inflammatory disorders. The formation of mature IL-1β from an inactive pro-IL-1β precursor is produced via nonconventional multiprotein complexes called the inflammasomes, of which the most common is the nucleotide-binding domain leucine-rich repeat-containing protein 3 (NLRP3) inflammasome composed by NLRP3, (ASC) apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (CARD), and caspase-1. Specialized proresolving mediators (SPMs) promote resolution of inflammation, which is an essential process to maintain host health. SPMs prevent excessive inflammation by terminating the inflammatory response and returning to tissue homeostasis without immunosupression. This study tested the hypothesis that modulation of the NLRP3 inflammasome in macrophages is one mechanism involved in the SPM-regulated processes during resolution. Our findings demonstrate that the SPM resolvin D2 (RvD2) suppressed the expression of pro-IL-1β and reduced the secretion of mature IL-1β in bone marrow-derived macrophages challenged with LPS+ATP (classical NLRP3 inflammasome model) or LPS+palmitate (lipotoxic model). Similar findings were observed in thioglycolate-elicited peritoneal macrophages, in which RvD2 remarkably reduced ASC oligomerization, inflammasome assembly, and caspase-1 activity. In vivo, in a self-resolving zymosan A-induced peritonitis model, RvD2 blocked the NLRP3 inflammasome leading to reduced release of IL-1β into the exudates, repression of osteopontin, and MCP-1 expression and induction of M2 markers of resolution (i.e., CD206 and arginase-1) in peritoneal macrophages. RvD2 inhibitory actions were receptor mediated and were abrogated by a selective GPR18 antagonist. Together, these findings support the hypothesis that SPMs have the ability to inhibit the priming and to expedite the deactivation of the NLRP3 inflammasome in macrophages during the resolution process.

Topics: Adenosine Triphosphate; Animals; Bone Marrow Cells; Caspase 1; Caspase Inhibitors; Docosahexaenoic Acids; Inflammasomes; Inflammation; Lipopolysaccharides; Macrophage Activation; Macrophages, Peritoneal; Male; Mice, Inbred C57BL; NLR Family, Pyrin Domain-Containing 3 Protein; Palmitic Acid; Phenotype; Zymosan

Ischemic stroke is an acute and severe neurological disease, resulting in disability and death. Reperfusion to an ischemic brain is a means to reverse brain damage after stroke; however, this causes secondary tissue damage induced by inflammation responses, called ischemia/reperfusion (I/R) injury. Adhesion of neutrophils to endothelial cells underlies the initiation of inflammation in I/R. Inspired by this interaction, we report a drug delivery system comprised of neutrophil membrane-derived nanovesicles loaded with Resolvin D2 (RvD2) that can enhance resolution of inflammation, thus protecting brain damage during ischemic stroke. In the study, the middle cerebral artery occlusion (MCAO) mouse model was developed to mimic ischemic stroke. Using intravital microscopy of a live mouse brain, we visualized the binding of nanovesicles to inflamed brain vasculature for delivery of therapeutics to ischemic stroke lesions in real-time. We also observed that RvD2-loaded nanovesicles dramatically decreased inflammation in ischemic stroke and improved mouse neurological functions. Our study provides a strategy to inhibit neuroinflammation using neutrophil-derived nanovesicles for ischemic stroke therapy.

Topics: Animals; Brain Injuries; Cell Adhesion; Cell Membrane; Disease Models, Animal; Docosahexaenoic Acids; Drug Carriers; Drug Delivery Systems; Endothelial Cells; Infarction, Middle Cerebral Artery; Inflammation; Male; Mice; Mice, Inbred C57BL; Nanoparticles; Neutrophils; Reperfusion Injury; Stroke

Periapical periodontitis results from pulpal infection leading to pulpal necrosis and resorption of periapical bone. The current treatment is root canal therapy, which attempts to eliminate infection and necrotic tissue. But, in some cases periapical inflammation doesn't resolve even after treatment. Resolvins belongs to a large family of specialized pro-resolving lipid mediators that actively resolves inflammation signaling via specific receptors. Resolvin D2 (RvD2), a metabolite of docosahexaenoic acid (DHA), was tested as an intracanal medicament in rats

Topics: Animals; Cells, Cultured; Dental Pulp; Docosahexaenoic Acids; Extracellular Matrix Proteins; Gene Expression; Inflammation; Male; Periapical Periodontitis; Periapical Tissue; Phosphoproteins; Phosphorylation; Rats, Wistar; Receptors, Cannabinoid; Root Canal Therapy; STAT3 Transcription Factor; Wound Healing; X-Ray Microtomography

While the treatment of inflammatory disorders is generally based on inhibiting factors that drive onset of inflammation, these therapies can compromise healing (NSAIDs) or dampen immunity against infections (biologics). In search of new antiinflammatories, efforts have focused on harnessing endogenous pathways that drive resolution of inflammation for therapeutic gain. Identification of specialized pro-resolving mediators (SPMs) (lipoxins, resolvins, protectins, maresins) as effector molecules of resolution has shown promise in this regard. However, their action on inflammatory resolution in humans is unknown. Here, we demonstrate using a model of UV-killed Escherichia coli-triggered skin inflammation that SPMs are biosynthesized at the local site at the start of resolution, coinciding with the expression of receptors that transduce their actions. These include receptors for lipoxin A4 (ALX/FPR2), resolvin E1 (ChemR23), resolvin D2 (GPR18), and resolvin D1 (GPR32) that were differentially expressed on the endothelium and infiltrating leukocytes. Administering SPMs into the inflamed site 4 hours after bacterial injection caused a reduction in PMN numbers over the ensuing 6 hours, the phase of active resolution in this model. These results indicate that in humans, the appearance of SPMs and their receptors is associated with the beginning of inflammatory resolution and that their therapeutic supplementation enhanced the resolution response.

Topics: Adaptor Proteins, Signal Transducing; Adolescent; Adult; Anti-Inflammatory Agents; Blister; Chemokines; Cytokines; Docosahexaenoic Acids; Eicosanoids; Eicosapentaenoic Acid; Escherichia coli; Humans; Inflammation; Leukocytes; Lipoxins; Male; Middle Aged; Neutrophils; Receptors, Chemokine; Receptors, Formyl Peptide; Receptors, G-Protein-Coupled; Receptors, Lipoxin; Skin; Volunteers; Young Adult

15-lipoxygenase is involved in the generation of specialized pro-resolving lipid mediators that play essential roles in resolution and inflammatory responses. Here, we investigated anti-inflammatory role of Alox15 in skin homeostasis. We demonstrated that knockout (KO) of Alox15 led to hair loss and disrupted the structural integrity of the dorsal skin. Alox15 KO resulted in loss of hair follicle stem cells and abnormal transition of dermal adipocytes into fibroblasts. Alox15 deficiency increased infiltration of proinflammatory macrophages and upregulated proinflammatory and necroptotic signaling in dermal adipose tissue in the dorsal skin. Lipidomic analysis revealed severe loss of resolvin D2 in the dorsal skin of Alox15 KO mice compared to wild type controls. Treatment with resolvin D2 reduced skin inflammation in Alox15 KO mice. Collectively, these results indicate that Alox15-mediated production of resolvin D2 is required to maintain skin integrity by suppressing dermal inflammation.

Topics: Adipocytes; Alopecia; Animals; Arachidonate 12-Lipoxygenase; Arachidonate 15-Lipoxygenase; Cell Death; Docosahexaenoic Acids; Fibroblasts; Gene Knockout Techniques; Hair Follicle; Homeostasis; Inflammation; Inflammation Mediators; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Skin

Topics: Animals; Chromatography, Liquid; Disease Models, Animal; Docosahexaenoic Acids; Inflammation; Macrophages; Male; Mice; Mice, Knockout; Phagocytosis; Receptors, G-Protein-Coupled; Sepsis; Tandem Mass Spectrometry

Essentials Specialized proresolving mediators (SPMs) promote the resolution of inflammation. This study sought to investigate the effects of SPMs on human platelet function. The SPM, Maresin 1, enhanced hemostatic, but suppressed inflammatory functions of platelets. SPMs uniquely regulate platelet function and may represent a new class of antiplatelet agents.. Background Antiplatelet therapy is a cornerstone of modern medical practice and is routinely employed to reduce the likelihood of myocardial infarction, thrombosis and stroke. However, current antiplatelet therapies, such as aspirin, often have adverse side-effects, including increased risk of bleeding, and some patients are relatively 'aspirin-resistant'. Platelets are intimately involved in hemostasis and inflammation, and clinical consequences are associated with excessive or insufficient platelet activation. Objectives A major unmet need in the field of hematology is the development of new agents that safely prevent unwanted platelet activation in patients with underlying cardiovascular disease, while minimizing the risk of bleeding. Here, we investigate the potential of endogenously produced, specialized pro-resolving mediators (SPMs) as novel antiplatelet agents. SPMs are a recently discovered class of lipid-derived molecules that drive the resolution of inflammation without being overtly immunosuppressive. Methods Human platelets were treated with lipoxin A4, resolvin D1, resolvin D2, 17-HDHA or maresin 1 for 15 min, then were subjected to platelet function tests, including spreading, aggregation and inflammatory mediator release. Results We show for the first time that human platelets express the SPM receptors, GPR32 and ALX. Furthermore, our data demonstrate that maresin 1 differentially regulates platelet hemostatic function by enhancing platelet aggregation and spreading, while suppressing release of proinflammatory and prothrombotic mediators. Conclusions These data support the concept that SPMs differentially regulate platelet function and may represent a novel class of antiplatelet agents. SPMs also may play an important role in the resolution of inflammation in cardiovascular diseases.

Topics: Adaptor Proteins, Signal Transducing; Blood Platelets; Cardiovascular Diseases; Docosahexaenoic Acids; Hemostasis; Humans; Inflammation; Lipoxins; Myocardial Infarction; Phenotype; Platelet Activation; Platelet Aggregation Inhibitors; Platelet Function Tests; Receptors, G-Protein-Coupled

Resolution of inflammation is an active counter-regulatory mechanism involving polyunsaturated fatty acid-derived proresolving lipid mediators. Postoperative intestinal motility disturbances, clinically known as postoperative ileus, occur frequently after abdominal surgery and are mediated by a complex inflammation of the intestinal muscularis externa. Herein, we tested the hypothesis that proresolving lipid mediators are involved in the resolution of postoperative ileus. In a standardized experimental model of postoperative ileus, we detected strong expression of 12/15-lipoxygenase within the postoperative muscularis externa of C57BL/6 mice, predominately located within CX3CR1(+)/Ly6C(+) infiltrating monocytes rather than Ly6G(+) neutrophils. Mass spectrometry analyses demonstrated that a 12/15-lipoxygenase increase was accompanied by production of docosahexaenoic acid-derived lipid mediators, particularly protectin DX and resolvin D2, and their common precursor 17-hydroxy docosahexaenoic acid. Perioperative administration of protectin DX, but not resolvin D2 diminished blood-derived leukocyte infiltration into the surgically manipulated muscularis externa and improved the gastrointestinal motility. Flow cytometry analyses showed impaired Ly6G(+)/Ly6C(+) neutrophil extravasation after protectin DX treatment, whereas Ly6G(-)/Ly6C(+) monocyte numbers were not affected. 12/15-lipoxygenase-deficient mice, lacking endogenous protectin DX synthesis, demonstrated increased postoperative leukocyte levels. Preoperative intravenous administration of a docosahexaenoic acid-rich lipid emulsion reduced postoperative leukocyte infiltration in wild-type mice but failed in 12/15-lipoxygenase-deficient mice mice. Protectin DX application reduced leukocyte influx and rescued 12/15-lipoxygenase-deficient mice mice from postoperative ileus. In conclusion, our results show that 12/15-lipoxygenase mediates postoperative ileus resolution via production of proresolving docosahexaenoic acid-derived protectin DX. Perioperative, parenteral protectin DX or docosahexaenoic acid supplementation, as well as modulation of the 12/15-lipoxygenase pathway, may be instrumental in prevention of postoperative ileus.

Topics: Animals; Arachidonate 12-Lipoxygenase; Arachidonate 15-Lipoxygenase; Chemotaxis, Leukocyte; Docosahexaenoic Acids; Drug Evaluation, Preclinical; Emulsions; Fatty Acids, Omega-3; Gastrointestinal Motility; Ileus; Inflammation; Jejunum; Mice; Mice, Inbred C57BL; Models, Immunological; Muscle, Smooth; Neutrophils; Postoperative Complications; Specific Pathogen-Free Organisms

Innate immune dysfunction after major burn injuries increases the susceptibility to organ failure. Lipid mediators of inflammation resolution, e.g., resolvin D2, have been shown recently to restore neutrophil functionality and reduce mortality rate in a rat model of major burn injury. However, the physiological mechanisms responsible for the benefic activity of resolvin D2 are not well understood.. Prospective randomized animal investigation.. Academic research setting.. Wistar male rats.. Animals were subjected to a full-thickness burn of 30% total body surface area. Two hours after burn, 25 ng/kg resolvin D2 was administered IV and repeated every day, for 8 days. At day 10 post burn, 2 mg/kg of lipopolysaccharide was administered IV, and the presence of renal and hepatic injuries was evaluated at day 11 post burn by histology, immunohistochemistry, and relevant blood chemistry.. In untreated animals, we found significant tissue damage in the kidneys and liver, consistent with acute tubular necrosis and multifocal necrosis, and changes in blood chemistry, reflecting the deterioration of renal and hepatic functions. We detected less tissue damage and significantly lower values of blood urea nitrogen (26.4 ± 2.1 vs 36.0 ± 9.3 mg/dL; p ≤ 0.001), alanine aminotransferase (266.5 ± 295.2 vs 861.8 ± 813.7 U/L; p ≤ 0.01), and total bilirubin (0.13 ± 0.05 vs 0.30 ± 0.14 mg/dL; p ≤ 0.01) in resolvin D2-treated rats than in untreated animals. The mean blood pressure of all animals was above 65 mm Hg, indicating adequate tissue perfusion throughout the experiments. We measured significantly larger amounts of chromatin in the circulation of untreated than of resolvin D2-treated rats (575.1 ± 331.0 vs 264.1 ± 122.4 ng/mL; p ≤ 0.05) and identified neutrophil extracellular traps in kidney and liver tissues from untreated rats, consistent with the tissue damage.. Pathologic changes in kidney and liver tissues in a rat model of major burn and endotoxin insults are ameliorated by resolvin D2.

Topics: Animals; Blood Chemical Analysis; Body Weight; Burns; Disease Models, Animal; Docosahexaenoic Acids; Hemodynamics; Hepatic Insufficiency; Inflammation; Inflammation Mediators; Kidney Function Tests; Lipopolysaccharides; Liver Function Tests; Low Density Lipoprotein Receptor-Related Protein-2; Male; Prospective Studies; Random Allocation; Rats; Rats, Wistar; Renal Insufficiency

Pro-resolving, docosahexaenoic acid-derived mediators have recently emerged as important potential therapeutic agents for the amelioration of complications arising from inflammation, such as vascular disease, asthma, acute lung injury and colitis. While resolvin D1 (RVD1), resolvin D2 (RVD2) and maresin 1 (MaR1) are established pro-resolvins, their mechanisms of action remain unclear. Here we show that, in LPS-stimulated primary human monocytes, RVD1, RVD2 and MaR1 each suppress the release of pro-inflammatory cytokines (TNF, IL-1β, IL-8) and the innate/adaptive bridging cytokine, IL-12 p40, while simultaneously augmenting the production of the anti-inflammatory cytokine, IL-10. Such resolving activity is accompanied by the increased phosphorylation (enhanced anti-inflammatory state) of glycogen synthase kinase 3β (GSK3β) along with increased phosphorylation (activation) of Akt, SGK1 and CREB but not MAPK-related molecules. Gain and loss of function experiments confirm a key role for GSK3β and CREB in the anti-inflammatory actions of resolvins. These results suggest that induction of the GSK3β anti-inflammatory axis is a common mechanism of action for RVD1, RVD2 and MaR1.

Topics: Anti-Inflammatory Agents; Cells, Cultured; Cyclic AMP Response Element-Binding Protein; Cytokines; Docosahexaenoic Acids; Glycogen Synthase Kinase 3 beta; Humans; Immediate-Early Proteins; Indoles; Inflammation; Lipopolysaccharides; Maleimides; Monocytes; Phosphorylation; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; RNA, Small Interfering; Toll-Like Receptor 4

Resolvins are lipid mediators generated by leukocytes during the resolution phase of inflammation. They have been shown to regulate the transition from inflammation to tissue repair; however, it is unknown whether resolvins play a role in tissue revascularization following ischemia.. We used a murine model of hind limb ischemia (HLI), coupled with laser Doppler perfusion imaging, microcomputed tomography, and targeted mass spectrometry, to assess the role of resolvins in revascularization and inflammation resolution.. In mice undergoing HLI, we identified resolvin D2 (RvD2) in bone marrow and skeletal muscle by mass spectrometry (n=4-7 per group). We also identified RvD2 in skeletal muscle biopsies from humans with peripheral artery disease. Monocytes were recruited to skeletal muscle during HLI and isolated monocytes produced RvD2 in a lipoxygenase-dependent manner. Exogenous RvD2 enhanced perfusion recovery in HLI and microcomputed tomography of limb vasculature revealed greater volume, with evidence of tortuous arterioles indicative of arteriogenesis (n=6-8 per group). Unlike other treatment strategies for therapeutic revascularization that exacerbate inflammation, RvD2 did not increase vascular permeability, but reduced neutrophil accumulation and the plasma levels of tumor necrosis factor-α and granulocyte macrophage colony-stimulating factor. In mice treated with RvD2, histopathologic analysis of skeletal muscle of ischemic limbs showed more regenerating myocytes with centrally located nuclei. RvD2 enhanced endothelial cell migration in a Rac-dependent manner, via its receptor, GPR18, and Gpr18-deficient mice had an endogenous defect in perfusion recovery following HLI. Importantly, RvD2 rescued defective revascularization in diabetic mice.. RvD2 stimulates arteriogenic revascularization during HLI, suggesting that resolvins may be a novel class of mediators that both resolve inflammation and promote arteriogenesis.

Topics: Animals; Cells, Cultured; Cohort Studies; Docosahexaenoic Acids; Female; Hindlimb; Humans; Inflammation; Ischemia; Male; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Knockout; Mice, Obese; Middle Aged; Peripheral Arterial Disease

Resolution of inflammation is a finely regulated process mediated by specialized proresolving lipid mediators (SPMs), including docosahexaenoic acid (DHA)-derived resolvins and maresins. The immunomodulatory role of SPMs in adaptive immune cells is of interest. We report that D-series resolvins (resolvin D1 and resolvin D2) and maresin 1 modulate adaptive immune responses in human peripheral blood lymphocytes. These lipid mediators reduce cytokine production by activated CD8(+) T cells and CD4(+) T helper 1 (TH1) and TH17 cells but do not modulate T cell inhibitory receptors or abrogate their capacity to proliferate. Moreover, these SPMs prevented naïve CD4(+) T cell differentiation into TH1 and TH17 by down-regulating their signature transcription factors, T-bet and Rorc, in a mechanism mediated by the GPR32 and ALX/FPR2 receptors; they concomitantly enhanced de novo generation and function of Foxp3(+) regulatory T (Treg) cells via the GPR32 receptor. These results were also supported in vivo in a mouse deficient for DHA synthesis (Elovl2(-/-)) that showed an increase in TH1/TH17 cells and a decrease in Treg cells compared to wild-type mice. Additionally, either DHA supplementation in Elovl2(-/-) mice or in vivo administration of resolvin D1 significantly reduced cytokine production upon specific stimulation of T cells. These findings demonstrate actions of specific SPMs on adaptive immunity and provide a new avenue for SPM-based approaches to modulate chronic inflammation.

Topics: Acetyltransferases; Adaptive Immunity; Adaptor Proteins, Signal Transducing; Animals; Cell Differentiation; Docosahexaenoic Acids; Fatty Acid Elongases; Humans; Inflammation; Inflammation Mediators; Interleukin-2; Lipid Metabolism; Lymphocyte Activation; Mice; Mice, Knockout; Receptors, Formyl Peptide; Receptors, G-Protein-Coupled; Receptors, Lipoxin; T-Lymphocyte Subsets; T-Lymphocytes

Inflammation is a major burden in respiratory diseases, resulting in airway hyperresponsiveness. Our hypothesis is that resolution of inflammation may represent a long-term solution in preventing human bronchial dysfunctions. The aim of the present study was to assess the anti-inflammatory effects of RvD2, a member of the D-series resolving family, with concomitant effects on ASM mechanical reactivity. The role and mode of action of RvD2 were assessed in an in vitro model of human bronchi under pro-inflammatory conditions, induced either by 1 μM LTD4 or 10 ng/ml TNF-α pre-treatment for 48h. TNF-α and LTD4 both induced hyperreactivity in response to pharmacological stimuli. Enhanced 5-Lipoxygenase (5-LOX) and cysteinyl leukotriene receptor 1 (CysLTR1) detection was documented in LTD4 or TNF-α pre-treated human bronchi when compared to control (untreated) human bronchi. In contrast, RvD2 treatments reversed 5-LOX/β-actin and CysLTR1/β-actin ratios and decreased the phosphorylation levels of AP-1 subunits (c-Fos, c-Jun) and p38-MAP kinase, while increasing the detection of the ALX/FPR2 receptor. Moreover, various pharmacological agents revealed the blunting effects of RvD2 on LTD4 or TNF-α induced hyper-responsiveness. Combined treatment with 300 nM RvD2 and 1 μM WRW4 (an ALX/FPR2 receptor inhibitor) blunted the pro-resolving and broncho-modulatory effects of RvD2. The present data provide new evidence regarding the role of RvD2 in a human model of airway inflammation and hyperrresponsiveness.

Topics: Actins; Arachidonate 5-Lipoxygenase; Blotting, Western; Bronchi; Bronchoconstriction; Docosahexaenoic Acids; Humans; Inflammation; Leukotriene D4; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Receptors, Leukotriene; Tissue Culture Techniques; Transcription Factor AP-1; Tumor Necrosis Factor-alpha

Timely resolution of inflammation is crucial for normal wound healing. Resolution of inflammation is an active biological process regulated by specialized lipid mediators including the lipoxins and resolvins. Failure of resolution activity has a major negative impact on wound healing in chronic inflammatory diseases that is manifest as excess fibrosis and scarring. Lipoxins, including Lipoxin A4 (LXA4), have known anti-fibrotic and anti-scarring properties. The goal of this study was to elucidate the impact of LXA4 on fibroblast function. Mouse fibroblasts (3T3 Mus musculus Swiss) were cultured for 72 h in the presence of TGF-β1, to induce fibroblast activation. The impact of exogenous TGF-β1 (1 ng/mL) on LXA4 receptor expression (ALX/FPR2) was determined by flow cytometry. Fibroblast proliferation was measured by bromodeoxyuridine (BrdU) labeling and migration in a "scratch" assay wound model. Expression of α-smooth muscle actin (α-SMA), and collagen types I and III were measured by Western blot. We observed that TGF-β1 up-regulates LXA4 receptor expression, enhances fibroblast proliferation, migration and scratch wound closure. α-SMA levels and Collagen type I and III deposition were also enhanced. LXA4 slowed fibroblast migration and scratch wound closure at early time points (24 h), but wound closure was equal to TGF-β1 alone at 48 and 72 h. LXA4 tended to slow fibroblast proliferation at both concentrations, but had no impact on α-SMA or collagen production by TGF-β1 stimulated fibroblasts. The generalizability of the actions of resolution molecules was examined in experiments repeated with resolvin D2 (RvD2) as the agonist. The activity of RvD2 mimicked the actions of LXA4 in all assays, through an as yet unidentified receptor. The results suggest that mediators of resolution of inflammation enhance wound healing and limit fibrosis in part by modulating fibroblast function.

Topics: 3T3 Cells; Actins; Animals; Cell Differentiation; Cell Proliferation; Collagen Type I; Collagen Type III; Docosahexaenoic Acids; Fibroblasts; Inflammation; Lipoxins; Mice; Myofibroblasts; Receptors, Formyl Peptide; Transforming Growth Factor beta1; Wound Healing

This study evaluated the alveolar bone response to testosterone and the impact of Resolvin D2 (RvD2) on testosterone-induced osteoblast function. For the in vivo characterization, 60 male adult rats were used. Treatments established sub-physiologic (L), normal (N), or supra-physiologic (H) concentrations of testosterone. Forty rats were subjected to orchiectomy; 20 rats received periodical testosterone injections while 20 rats received testicular sham-operation. Four weeks after the surgeries, 10 rats in each group received a subgingival ligature around the lower first molars to induce experimental periodontal inflammation and bone loss. In parallel, osteoblasts were differentiated from neonatal mice calvariae and treated with various doses of testosterone for 48 h. Cell lysates and conditioned media were used for the determination of alkaline phosphatase, osteocalcin, RANKL, and osteoprotegerin. Micro-computed tomography linear analysis demonstrated that bone loss was significantly increased for both L and H groups compared to animals with normal levels of testosterone. Gingival IL-1β expression was increased in the L group (p<0.05). Ten nM testosterone significantly decreased osteocalcin, RANKL, and OPG levels in osteoblasts; 100 nM significantly increased the RANKL:OPG ratio. RvD2 partially reversed the impact of 10 nM testosterone on osteocalcin, RANKL, and OPG. These findings suggest that both L and H testosterone levels increase inflammatory bone loss in male rats. While low testosterone predominantly increases the inflammatory response, high testosterone promotes a higher osteoblast-derived RANKL:OPG ratio. The proresolving mediator RvD2 ameliorates testosterone-derived downregulation of osteocalcin, RANKL, and OPG in primary murine osteoblasts suggesting a direct role of inflammation in osteoblast function.

Topics: Alkaline Phosphatase; Animals; Bone and Bones; Cells, Cultured; Cytokines; Docosahexaenoic Acids; Down-Regulation; Inflammation; Male; Mice; Osteoblasts; Osteocalcin; Osteoprotegerin; Periodontal Diseases; RANK Ligand; Rats; Testosterone; X-Ray Microtomography

The unprecedented increase in the prevalence of obesity and obesity-related disorders is causally linked to a chronic state of low-grade inflammation in adipose tissue. Timely resolution of inflammation and return of this tissue to homeostasis are key to reducing obesity-induced metabolic dysfunctions. In this study, with inflamed adipose, we investigated the biosynthesis, conversion, and actions of Resolvins D1 (RvD1, 7S,8R,17S-trihydroxy-4Z,9E,11E,13Z,15E,19Z-docosahexaenoic acid) and D2 (RvD2, 7S,16R,17S-trihydroxy-4Z,8E,10Z,12E,14E,19Z-docosahexaenoic acid), potent anti-inflammatory and proresolving lipid mediators (LMs), and their ability to regulate monocyte interactions with adipocytes. Lipid mediator-metabololipidomics identified RvD1 and RvD2 from endogenous sources in human and mouse adipose tissues. We also identified proresolving receptors (i.e., ALX/FPR2, ChemR23, and GPR32) in these tissues. Compared with lean tissue, obese adipose showed a deficit of these endogenous anti-inflammatory signals. With inflamed obese adipose tissue, RvD1 and RvD2 each rescued impaired expression and secretion of adiponectin in a time- and concentration-dependent manner as well as decreasing proinflammatory adipokine production including leptin, TNF-α, IL-6, and IL-1β. RvD1 and RvD2 each reduced MCP-1 and leukotriene B₄-stimulated monocyte adhesion to adipocytes and their transadipose migration. Adipose tissue rapidly converted both resolvins (Rvs) to novel oxo-Rvs. RvD2 was enzymatically converted to 7-oxo-RvD2 as its major metabolic route that retained adipose-directed RvD2 actions. These results indicate, in adipose, D-series Rvs (RvD1 and RvD2) are potent proresolving mediators that counteract both local adipokine production and monocyte accumulation in obesity-induced adipose inflammation.

Topics: Animals; Diet, High-Fat; Docosahexaenoic Acids; Humans; Inflammation; Inflammation Mediators; Mice; Mice, Inbred C57BL; Mice, Obese; Subcutaneous Fat

Resolvins and protectins are families of local lipid mediators generated from the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) during self-limited resolution of inflammation. We aimed to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay to measure these lipid mediators in human blood following n-3 fatty acid supplementation and to determine whether the blood collection method affects their measured concentration.. Blood samples from 20 healthy volunteers enrolled in an n-3 fatty acid supplementation trial were collected in EDTA, heparin, or citrate, or prepared as serum after volunteers had undergone 3 weeks of supplementation. Plasma or serum was purified by solid-phase chromatography and analyzed with LC-MS/MS.. The assay identified 18R/S-hydroxy-5Z,8Z,11Z,14Z,16E-eicosapentaenoic acid (18R/S-HEPE); 17S-hydroxy-4Z,7Z,10Z,13Z,15E,19Z-docosahexaenoic acid (17R/S-HDHA); 7S,8R,17S-trihydroxy-4Z,9E,11E,13Z,15E,19Z-docosahexaenoic acid (RvD1); 7S,8R,17R-trihydroxy-4Z,9E,11E,13Z,15E19Z-docosahexaenoicacid (17R-RvD1); 7S,16R,17S-trihydroxy-4Z,8E,10Z,12E,14E,19Z-docosahexaenoic acid (RvD2); 10S,17S-dihydroxy-4Z,7Z,11E,13Z,15E,19Z-docosahexaenoicacid (10S,17S-DiHDHA); and 10R,17S-dihydroxy-4Z,7Z,11E,13E,15Z,19Z-docosahexaenoic acid (protectin D1, PD1). The limits of detection and quantification were 3 pg and 6 pg on-column, respectively. The pathway precursors 18R/S-HEPE and 17R/S-HDHA, but not the resolvins, were lower in serum compared with plasma. After n-3 fatty acid supplementation, mean (SD) EDTA plasma concentrations were: 18R/S-HEPE 386 (56) pg/mL, 17R/S-HDHA 365 (65) pg/mL, RvD2 26 (4) pg/mL, RvD1 31 (5) pg/mL, and 17R-RvD 161 (7) pg/mL. 10S,17S-DiHDHA and PD1 concentrations were below the limit of quantification.. This is the first study reporting 17R/S-HDHA, RvD1, and RvD2 concentrations measured in human blood following oral n-3 fatty acid supplementation. The concentrations of the antiinflammatory lipid mediators RvD1 and RvD2 were within the biological range known to have antiinflammatory and proresolving activities in isolated human leukocytes and in in vivo studies in mice.

Topics: Aged; Chromatography, Liquid; Dietary Supplements; Docosahexaenoic Acids; Eicosapentaenoic Acid; Female; Humans; Inflammation; Male; Middle Aged; Stereoisomerism; Tandem Mass Spectrometry

Inflammatory pain such as arthritic pain is typically treated with opioids and cyclo-oxygenase-2 inhibitors with well known side effects. Transient receptor potential subtype vanilloid 1 (TRPV1) and TRP ankyryn 1 (TRPA1) contribute importantly to the genesis of inflammatory pain via both peripheral mechanisms (peripheral sensitization) and spinal cord mechanisms (central sensitization). Although these TRP channels have been intensively studied, little is known about their endogenous inhibitors. Recent studies have demonstrated that the endogenous lipid mediators resolvins (RvE1 and RvD1), derived from ω-3 unsaturated fatty acids, are potent inhibitors for inflammatory pain, without noticeable side effects. However, the molecular mechanisms underlying resolvins' distinct analgesic actions in mice are unclear. RvD2 is a novel family member of resolvins. Here we report that RvD2 is a remarkably potent inhibitor of TRPV1 (IC(50) = 0.1 nm) and TRPA1 (IC(50) = 2 nm) in primary sensory neurons, whereas RvE1 and RvD1 selectively inhibited TRPV1 (IC(50) = 1 nm) and TRPA1 (IC(50) = 9 nm), respectively. Accordingly, RvD2, RvE1, and RvD1 differentially regulated TRPV1 and TRPA1 agonist-elicited acute pain and spinal cord synaptic plasticity [spontaneous EPSC (sEPSC) frequency increase]. RvD2 also abolished inflammation-induced sEPSC increases (frequency and amplitude), without affecting basal synaptic transmission. Intrathecal administration of RvD2 at very low doses (0.01-1 ng) prevented formalin-induced spontaneous pain. Intrathecal RvD2 also reversed adjuvant-induced inflammatory pain without altering baseline pain and motor function. Finally, intrathecal RvD2 reversed C-fiber stimulation-evoked long-term potentiation in the spinal cord. Our findings suggest distinct roles of resolvins in regulating TRP channels and identify RvD2 as a potent endogenous inhibitor for TRPV1/TRPA1 and inflammatory pain.

Topics: Animals; Docosahexaenoic Acids; Eicosapentaenoic Acid; Ganglia, Spinal; Inflammation; Male; Mice; Neuronal Plasticity; Neurons; Pain; Spinal Cord; TRPV Cation Channels

A growing body of evidence indicates that resolution of acute inflammation is an active process. Resolvins are a new family of lipid mediators enzymatically generated within resolution networks that possess unique and specific functions to orchestrate catabasis, the phase in which disease declines. Resolvin D2 (RvD2) was originally identified in resolving exudates, yet its individual contribution in resolution remained to be elucidated. Here, we establish RvD2's potent stereoselective actions in reducing excessive neutrophil trafficking to inflammatory loci. RvD2 decreased leukocyte-endothelial interactions in vivo by endothelial-dependent nitric oxide production, and by direct modulation of leukocyte adhesion receptor expression. In mice with microbial sepsis initiated by caecal ligation and puncture, RvD2 sharply decreased both local and systemic bacterial burden, excessive cytokine production and neutrophil recruitment, while increasing peritoneal mononuclear cells and macrophage phagocytosis. These multi-level pro-resolving actions of RvD2 translate to increased survival from sepsis induced by caecal ligation and puncture and surgery. Together, these results identify RvD2 as a potent endogenous regulator of excessive inflammatory responses that acts via multiple cellular targets to stimulate resolution and preserve immune vigilance.

Topics: Animals; Docosahexaenoic Acids; Endothelial Cells; Escherichia coli; Humans; Inflammation; Leukocytes; Macrophages; Male; Mice; Mice, Inbred C57BL; Nitric Oxide; Peritoneal Cavity; Peritonitis; Phagocytosis; Reactive Oxygen Species; Sepsis