protectin-d1 and Inflammation

Marine organisms are an important source of natural products with unique and diverse chemical structures that may hold the key for the development of novel drugs. Docosahexaenoic acid (DHA) is an omega-3 fatty acid marine natural product playing a crucial regulatory role in the resolution of inflammation and acting as a precursor for the biosynthesis of the anti-inflammatory specialized pro-resolving mediators (SPMs) resolvins, protectins, and maresins. These metabolites exert many beneficial actions including neuroprotection, anti-hypertension, or anti-tumorigenesis. As dysregulation of SPMs is associated with diseases of prolonged inflammation, the disclosure of their bioactivities may be correlated with anti-inflammatory and pro-resolving capabilities, offering new targets for drug design. The availability of these SPMs from natural resources is very low, but the evaluation of their pharmacological properties requires their access in larger amounts, as achieved by synthetic routes. In this report, the first review of the total organic syntheses carried out for resolvins, protectins, and maresins is presented. Recently, it was proposed that DHA-derived pro-resolving mediators play a key role in the treatment of COVID-19. In this work we also review the current evidence on the structures, biosynthesis, and functional and new-found roles of these novel lipid mediators of disease resolution.

Topics: Anti-Inflammatory Agents; COVID-19; COVID-19 Drug Treatment; Docosahexaenoic Acids; Drug Design; Humans; Inflammation; SARS-CoV-2

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

Acute inflammatory responses are protective, yet without timely resolution can lead to chronic inflammation and organ fibrosis. A systems approach to investigate self-limited (self-resolving) inflammatory exudates in mice and structural elucidation uncovered novel resolution phase mediators in vivo that stimulate endogenous resolution mechanisms in inflammation. Resolving inflammatory exudates and human leukocytes utilize DHA and other n-3 EFA to produce three structurally distinct families of potent di- and trihydroxy-containing products, with several stereospecific potent mediators in each family. Given their potent and stereoselective picogram actions, specific members of these new families of mediators from the DHA metabolome were named D-series resolvins (Resolvin D1 to Resolvin D6), protectins (including protectin D1-neuroprotectin D1), and maresins (MaR1 and MaR2). In this review, we focus on a) biosynthesis of protectins and maresins as anti-inflammatory-pro-resolving mediators; b) their complete stereochemical assignments and actions in vivo in disease models. Each pathway involves the biosynthesis of epoxide-containing intermediates produced from hydroperoxy-containing precursors from human leukocytes and within exudates. Also, aspirin triggers an endogenous DHA metabolome that biosynthesizes potent products in inflammatory exudates and human leukocytes, namely aspirin-triggered Neuroprotectin D1/Protectin D1 [AT-(NPD1/PD1)]. Identification and structural elucidation of these new families of bioactive mediators in resolution has opened the possibility of diverse patho-physiologic actions in several processes including infection, inflammatory pain, tissue regeneration, neuroprotection-neurodegenerative disorders, wound healing, and others. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

Topics: Animals; Anti-Inflammatory Agents; Aspirin; Docosahexaenoic Acids; Humans; Inflammation; Lipoxygenases; Metabolome; Molecular Structure; Signal Transduction; Structure-Activity Relationship

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have long been associated with decreased inflammation and are also implicated in the prevention of tumorigenesis. Conventional thinking attributed this mainly to a suppressive effect of these fatty acids on the formation of arachidonic acid-derived prostaglandins and leukotrienes. Recent years have seen the discovery of a new class of inflammation-dampening and resolution-promoting n-3 PUFA-derived lipid mediators called resolvins and protectins. Chemically, these compounds are hydroxylated derivatives of the parent n-3 PUFA eicosapentaenoic acid (EPA) for the E-resolvins, and docosahexaenoic acid (DHA) for the D-resolvins and protectin D1. While a relatively large number of these compounds have been identified and characterized until now, with differences in the positions of the hydroxyl-groups as well as in the chirality at the different carbon atoms, all compounds share common precursor metabolites, 17-hydroperoxydocosahexaenoic acid (17-H(p)DHA) for the DHA-derived compounds and 18-hydroperoxyeicosapentaenoic acid (18-H(p)EPE) for the EPA-derived compounds. In this review we summarize the current knowledge about EPA- and DHA-derived resolvins and protectins and explore the potential use of the pro-resolvins 17-hydroxydocosahexaenoic acid (17-HDHA) and 18-hydroxyeicosapentaenoic acid (18-HEPE) as indicators of anti-inflammatory n-3 PUFA mediator formation.

Topics: Animals; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Omega-3; Humans; Inflammation

Neurodegenerative diseases encompass complex cell signaling disturbances that initially damage neuronal circuits and synapses. Due to multiple protective mechanisms enacted to counteract the onset of neurodegenerative diseases, there is often a prolonged period without noticeable impairments during their initiation. Since severe cognitive deficit or vision loss takes place after that period there is an opportunity to harness endogenous protective mechanisms as potential therapeutic approaches. The activation of the biosynthesis of the docosanoid mediator neuroprotectin D1 (NPD1) is an early response to the upsurge of protein misfolding and other neuroinflammatory events. This overview discusses the potent neuroprotective and inflammation-modulating bioactivity of NPD1. This lipid mediator represents an early response to neurodegenerations, aiming to restore homeostasis.

Topics: Amino Acid Sequence; Amyloid beta-Peptides; Animals; Docosahexaenoic Acids; Humans; Inflammation; Molecular Sequence Data; Nervous System; Proteostasis Deficiencies; Trinucleotide Repeat Expansion

Aging is associated with an enhanced susceptibility to brain dysfunction, loss of memory, and cognitive decline and significantly influences the quality of life for the affected individual. Recent molecular-genetic approaches have provided powerful insights into common age-related diseases that are both progressive and multifactorial, such as Alzheimer's disease (AD), and in vitro in AD models. These investigations have uncovered consistent deficits in brain gene signaling mechanisms and neurotrophic substances known to contribute to normal brain function. Inflammatory signaling pathways involving up-regulation of cytosolic phospholipase A(2) and the arachidonic acid cycle, the depletion of the brain-essential fatty acid docosahexaenoic acid (DHA) and DHA-derived neuroprotectin D1, and changes in the expression of key proapoptotic and antiapoptotic members of the Bcl-2 gene family are thought to be major contributors to pathogenic processes in degenerating brain tissue. This review will focus on the roles of stress genes, apoptosis-related genes, and inflammation in the molecular genetics of AD with emphasis on the interactive nature of inflammatory, neurotrophic, and apoptotic signaling and will highlight areas of rapid progress in the characterization of action of DHA and neuroprotectin D1 and address important research challenges. We also attempt to integrate these molecular, genetic, and neurochemical changes with cellular pathways involved in brain aging to formulate an integrated understanding of multifactorial age-related neurologic disease and pharmacotherapeutic strategies that may be useful in the restoration of homeostatic brain function.

Topics: Alzheimer Disease; Animals; Apoptosis; Cell Survival; Docosahexaenoic Acids; Humans; Inflammation; Signal Transduction

Research on the formation of novel enzymatic oxygenation products derived from the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has revealed the endogenous formation of several novel autacoids that have been termed resolvins and protectins. The elucidation of the chemical structures of resolvins and protectins, and the assessment of their endogenous functions, are providing a new understanding of the role of endogenous omega-3 fatty acid-derived lipid mediators in tissue protection, counteraction of inflammation and the activation of inflammation resolution. This review emphasizes the structural aspects of resolvin biosynthesis and metabolic inactivation, which are of central importance for understanding the current and future development of therapeutically relevant, stable analogs that may activate inflammation resolution.

Topics: Animals; Anti-Inflammatory Agents; Aspirin; Docosahexaenoic Acids; Eicosapentaenoic Acid; Humans; Inflammation; Lipoxins; Molecular Structure; Signal Transduction; Structure-Activity Relationship

A well-integrated host inflammatory response is essential in maintaining health and fighting disease. It is important to achieve a complete understanding of the cellular and molecular events that govern the resolution of acute inflammation. Because novel lipid-derived mediators, called resolvins and protectins in animal models, control the duration and magnitude of inflammation, the mapping of these resolution circuits may provide new ways of understanding the molecular basis of many inflammatory diseases. This article provides an overview of recent studies on resolvin and protectin biosynthesis and of advances in understanding the actions of these novel anti-inflammatory and proresolving lipid mediators. These new families of lipid-derived mediators were originally isolated from experimental murine models of acute inflammation identified during the natural spontaneous resolution phase. They are biosynthesized from omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid) and possess potent anti-inflammatory, proresolving, and antifibrotic actions in vivo. Taken together, these findings suggest that defective resolution mechanisms may underlie the inflammatory phenotypes that are believed to characterize many common human diseases. The new families of endogenous proresolving and anti-inflammatory agonists constitute a new genus of anti-inflammatories.

Topics: Acute Disease; Animals; Anti-Inflammatory Agents; Disease Models, Animal; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Omega-3; Humans; Inflammation; Inflammation Mediators; Lipoxins

The physiological resolution of a well-orchestrated inflammatory response is essential to maintain homeostasis. Therefore, gaining a comprehensive understanding in molecular terms of the events that direct the termination of acute inflammation is imperative. Recently, new families of local-acting mediators were discovered that are biosynthesized from the essential fatty acids eicosapentaenoic acid and docosahexaenoic acid. These new chemical mediators are endogenously generated in inflammatory exudates collected during the resolution phase, and were termed resolvins and protectins because specific members of these families control the magnitude and duration of inflammation in animals. In addition, recent results indicate novel actions of resolvins and protectins in removing chemokines ferried from the tissue by apoptotic neutrophils and T cells during resolution. Here, we review recent advances on the biosynthesis and actions of these novel anti-inflammatory and proresolving mediators.

Topics: Acute Disease; Animals; Docosahexaenoic Acids; Eicosapentaenoic Acid; Humans; Inflammation; Inflammation Mediators; Multigene Family

Synaptic activity and ischemia/injury promote lipid messenger formation through phospholipase-mediated cleavage of specific phospholipids from membrane reservoirs. Lipid messengers modulate signaling cascades, contributing to development, differentiation, function (e.g., memory), protection, regeneration, and repair of neurons and overall regulation of neuronal, glial, and endothelial cell functional integrity. Oxidative stress disrupts lipid signaling and promotes lipid peroxidation and neurodegeneration. Lipid signaling at the neurovascular unit (neurons, astrocytes, oligodendrocytes, microglia, and cells of the microvasculature) is altered in early cerebrovascular and neurodegenerative disease. We discuss how lipid signaling regulates critical events in neuronal survival. Aberrant synaptic plasticity (e.g., epileptogenesis) is highlighted to show how gene expression may drive synaptic circuitry formation in the "wrong" direction. Docosahexaenoic acid has been implicated in memory, photoreceptor cell biogenesis and function, and neuroprotection. Free docosahexaenoic acid released in the brain during experimental stroke leads to the synthesis of stereospecific messengers through oxygenation pathways. One messenger, 10,17S-docosatriene (neuroprotectin D1; NPD1), counteracts leukocyte infiltration and proinflammatory gene expression in brain ischemia-reperfusion. In retina, photoreceptor survival depends on retinal pigment epithelial (RPE) cell integrity. NPD1 is synthesized in RPE cells undergoing oxidative stress, potently counteracts oxidative stress-triggered apoptotic DNA damage in RPE, upregulates antiapoptotic proteins Bcl-2 and Bcl-x(L), and decreases proapoptotic Bax and Bad expression. These findings expand our understanding of how the nervous system counteracts redox disturbances, mitochondrial dysfunction, and proinflammatory conditions. The specificity and potency of NPD1 indicate a potential target for therapeutic intervention for stroke, age-related macular degeneration, spinal cord injury, and other neuroinflammatory or neurodegenerative diseases.

Topics: Animals; Brain; Brain Injuries; Docosahexaenoic Acids; Humans; Inflammation; Neurodegenerative Diseases; Oxidative Stress; Phospholipids; Second Messenger Systems; Signal Transduction

The production of specialized pro-resolving mediators (SPMs) during the resolution phase in the inflammatory milieu is key to orchestrating the resolution of the acute inflammatory response. 17-epi-neuroprotectin D1/17-epi-protectin D1 (17-epi-NPD1/17-epi-PD1: 10R,17R-dihydroxy-4Z,7Z,11E,13E,15Z,19Z-docosahexaenoic acid) is an SPM of the protectin family, biosynthesized from docosahexaenoic acid (DHA), that exhibits both potent anti-inflammatory and neuroprotective functions. Here, we carried out a new commercial-scale synthesis of 17-epi-NPD1/17-epi-PD1 that enabled the authentication and confirmation of its potent bioactions in vivo and determination of its ability to activate human leukocyte phagocytosis. We provide evidence that this new synthetic 17-epi-NPD1/17-epi-PD1 statistically significantly increases human macrophage uptake of E. coli in vitro and confirm that it limits neutrophilic infiltration in vivo in a murine model of peritonitis. The physical properties of the new synthetic 17-epi-NPD1/17-epi-PD1, namely its ultra-violet absorbance, chromatography, and tandem mass spectrometry fragmentation pattern, matched those of the originally synthesized 17-epi-NPD1/17-epi-PD1. In addition, we verified the structure and complete stereochemical assignment of this new synthetic 17-epi-NPD1/17-epi-PD1 using nuclear magnetic resonance (NMR) spectroscopy. Together, these results authenticate this 17-epi-NPD1/17-epi-PD1 for its structure and potent pro-resolving functions.

Topics: Animals; Docosahexaenoic Acids; Escherichia coli; Humans; Inflammation; Macrophages; Mice

Viral pneumonias are a major cause of morbidity and mortality, owing in part to dysregulated excessive lung inflammation, and therapies to modulate host responses to viral lung injury are urgently needed. Protectin conjugates in tissue regeneration 1 (PCTR1) and protectin D1 (PD1) are specialized pro-resolving mediators (SPMs) whose roles in viral pneumonia are of interest. In a mouse model of Respiratory Syncytial Virus (RSV) pneumonia, intranasal PCTR1 and PD1 each decreased RSV genomic viral load in lung tissue when given after RSV infection. Concurrent with enhanced viral clearance, PCTR1 administration post-infection, decreased eosinophils, neutrophils, and NK cells, including NKG2D

Topics: Administration, Intranasal; Animals; Docosahexaenoic Acids; Inflammation; Lung; Male; Mice; Pneumonia, Viral; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Viral Load

Topics: COVID-19; COVID-19 Drug Treatment; Dexamethasone; Docosahexaenoic Acids; Fatty Acids, Unsaturated; Humans; Inflammation; SARS-CoV-2

Traumatic brain injury (TBI) is followed by a secondary inflammation in the brain. Neuroprotectin D1 (NPD1) is synthesized from docosahexaenoic acid (DHA) and has anti-inflammatory and antiapoptotic effects in experimental models of neurodegenerative disease and brain ischemia-reperfusion. It is not known whether intralesional administration of NPD1 ameliorates inflammation and cell death after severe TBI. We therefore investigated the effects of NPD1 following a severe form of focal penetrating TBI. A total of 30 male Sprague-Dawley rats weighing between 350 and 450 g were exposed to focal penetrating TBI or sham surgery. The rats were randomized to NPD1 treatment (50 ng intralesionally, immediately following TBI) or no treatment. The rats were sacrificed at 24 or 72 h. All subgroups consisted of 5 rats. Brains were removed, fresh frozen, cut in 14-µm coronal sections and subjected to Fluoro-Jade, TUNEL, MnSOD, 3-NT, COX-2, Ox-42 and NF-κB immuno-staining and lesion size analyses. NPD1 decreased the lesion area at 72 h compared to no treatment with a mean change 42% (NPD1 14.1 mm

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Brain Injuries, Traumatic; Docosahexaenoic Acids; Head Injuries, Penetrating; Inflammation; Male; Rats; Rats, Sprague-Dawley

The mechanisms of pain induction by inflammation have been extensively studied. However, the mechanisms of pain resolution are not fully understood. Here, we report that GPR37, expressed by macrophages (MΦs) but not microglia, contributes to the resolution of inflammatory pain. Neuroprotectin D1 (NPD1) and prosaptide TX14 increase intracellular Ca2+ (iCa2+) levels in GPR37-transfected HEK293 cells. NPD1 and TX14 also bind to GPR37 and cause GPR37-dependent iCa2+ increases in peritoneal MΦs. Activation of GPR37 by NPD1 and TX14 triggers MΦ phagocytosis of zymosan particles via calcium signaling. Hind paw injection of pH-sensitive zymosan particles not only induces inflammatory pain and infiltration of neutrophils and MΦs, but also causes GPR37 upregulation in MΦs, phagocytosis of zymosan particles and neutrophils by MΦs in inflamed paws, and resolution of inflammatory pain in WT mice. Mice lacking Gpr37 display deficits in MΦ phagocytic activity and delayed resolution of inflammatory pain. Gpr37-deficient MΦs also show dysregulations of proinflammatory and antiinflammatory cytokines. MΦ depletion delays the resolution of inflammatory pain. Adoptive transfer of WT but not Gpr37-deficient MΦs promotes the resolution of inflammatory pain. Our findings reveal a previously unrecognized role of GPR37 in regulating MΦ phagocytosis and inflammatory pain resolution.

Topics: Animals; Docosahexaenoic Acids; HEK293 Cells; Humans; Inflammation; Macrophages, Peritoneal; Mice; Mice, Knockout; Neutrophils; Pain; Phagocytosis; Receptors, G-Protein-Coupled; Up-Regulation; Zymosan

Models of microbe-elicited peritonitis have been invaluable to identify mechanisms underlying inflammation resolution, but whether resolution mechanisms differ from an inflammatory agent to another has not been determined. Thus, we analyzed the cellular and molecular components of the resolution phase of non-microbe-induced inflammation. In thioglycollate (TG)-induced peritonitis, resolution started at 12 h (Tmax) and displayed a 22 h resolution interval (Ri). During resolution, lipoxin A4, resolvin (Rv) D1 and RvD2, protectin D1 (PD1), and maresin 1 (MaR1) were transiently produced while RvD5 was continually generated. In addition, docosahexaenoic acid (DHA)-derived mediators were produced to a higher extent than in microbial peritonitis. We also investigated leukocyte infiltration and clearance in peritoneal tissues surrounding the inflammatory site. In the omentum, resolution parameters, neutrophil apoptosis, and efferocytosis were similar to those of the peritoneal cavity. However, we noticed long-term persistence of M2-polarized macrophages and B-lymphocytes in the omentum after TG administration, whereas zymosan injection caused M1/M2-macrophage and T-lymphocyte persistence regardless of the magnitude of the inflammatory response. Our study indicates that some aspects of resolution are shaped in a stimulus-specific manner, and it ultimately argues that the tissues surrounding the inflammatory site must also be considered to address the inflammatory response globally.

Topics: Animals; Apoptosis; B-Lymphocytes; Blotting, Western; Cells, Cultured; Docosahexaenoic Acids; Female; Flow Cytometry; Immunoenzyme Techniques; Inflammation; Leukocytes; Lipids; Macrophages; Mice; Mice, Inbred C57BL; Omentum; Peritonitis; Phagocytosis; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Thioglycolates; Zymosan

The n-3 polyunsaturated fatty acids act as substrates during the resolution phase of acute inflammation for the biosynthesis of specialized pro-resolving lipid mediators. One premier example is the C22-dihydroxy-polyunsaturated fatty acid protectin D1 (1). The human 15-lipoxygenase type I, via stereoselective processes and with docosahexaenoic acid as the substrate, enables the formation of this specialized pro-resolving lipid mediator. Herein, based on results from LC/MS-MS metabololipidomics, support is presented for the apprehended biosynthesis of 1 in human macrophages occurring via the intermediate 16S,17S-epoxyprotectin (5). Stereochemically pure 5 was obtained using the Katsuki-Sharpless epoxidation protocol, establishing the chirality at the C16 and C17 atoms, one Z-selective reduction, and E- and Z-stereoselective Wittig reactions. In addition, information on the nonenzymatic aqueous hydrolysis products and the half-life of 16S,17S-epoxyprotectin (5) is presented.

Topics: Catalysis; CD59 Antigens; Chromatography, Liquid; Docosahexaenoic Acids; Fatty Acids, Unsaturated; Humans; Inflammation; Macrophages; Molecular Structure; Stereoisomerism

Protectin D1 (PD1), derived from docosahexaenoic acid, has been shown to control and resolve inflammation in some experimental models of inflammatory disorders. We investigated the protective roles of protectin D1 in pulmonary inflammation and lung injury induced by lipopolysaccharide (LPS).. Mice were randomly assigned to six groups (n = 6 per group): sham-vehicle group, sham-PD1 group, sham-zVAD-fmk group, LPS-vehicle group, LPS-PD1 group, and LPS-PD1-zVAD-fmk group. Mice were injected intratracheally with 3 mg/kg LPS or saline, followed 24 hours later by intravenous injection of 200 µg/mouse PD1 or vehicle. At the same time, some mice were also injected intraperitoneally with the pan-caspase inhibitor zVAD-fmk. Seventy-two hours after LPS challenge, samples of pulmonary tissue and bronchoalveolar lavage fluid were collected. Optical microscopy was used to examine pathological changes in lungs. Cellularity and protein concentration in bronchoalveolar lavage fluid were analyzed. Lung wet/dry ratios and myeloperoxidase activity were measured. Apoptosis of neutrophils in bronchoalveolar lavage fluid (BALF) was also evaluated by flow cytometry.. Intratracheal instillation of LPS increased neutrophil counts, protein concentration in bronchoalveolar lavage fluid and myeloperoxidase activity, it induced lung histological injury and edema, and also suppressed apoptosis of neutrophils in BALF. Posttreatment with PD1 inhibited LPS-evoked changes in BALF neutrophil counts and protein concentration and lung myeloperoxidase activity, with the outcome of decreased pulmonary edema and histological injury. In addition, PD1 promoted apoptosis of neutrophils in BALF. The beneficial effects of PD1 were blocked by zVAD-fmk.. Posttreatment with PD1 enhances resolution of lung inflammation during LPS-induced acute lung injury by enhancing apoptosis in emigrated neutrophils, which is, at least in part, caspase-dependent.

Topics: Acute Lung Injury; Animals; Apoptosis; Docosahexaenoic Acids; Inflammation; Lipopolysaccharides; Male; Mice; Mice, Inbred BALB C; Neutrophils; Peroxidase

Dysfunction of macrophages (MΦs) in diabetic wounds impairs the healing. MΦs produce anti-inflammatory and pro-resolving neuroprotectin/protectin D1 (NPD1/PD1, 10R,17S-dihydroxy-docosa-4Z,7Z,11E,13E,15Z,19Z-hexaenoic acid); however, little is known about endogenous NPD1 biosynthesis by MΦs and the actions of NPD1 on diabetic MΦ functions in diabetic wound healing. We used an excisional skin wound model of diabetic mice, MΦ depletion, MΦs isolated from diabetic mice, and mass spectrometry-based targeted lipidomics to study the time course progression of NPD1 levels in wounds, the roles of MΦs in NPD1 biosynthesis, and NPD1 action on diabetic MΦ inflammatory activities. We also investigated the healing, innervation, chronic inflammation, and oxidative stress in diabetic wounds treated with NPD1 or NPD1-modulated MΦs from diabetic mice. Injury induced endogenous NPD1 biosynthesis in wounds, but diabetes impeded NPD1 formation. NPD1 was mainly produced by MΦs. NPD1 enhanced wound healing and innervation in diabetic mice and promoted MΦs functions that accelerated these processes. The underlying mechanisms for these actions of NPD1 or NPD1-modulated MΦs involved 1) attenuating MΦ inflammatory activities and chronic inflammation and oxidative stress after acute inflammation in diabetic wound, and 2) increasing MΦ production of IL10 and hepatocyte growth factor. Taken together, NPD1 appears to be a MΦs-produced factor that accelerates diabetic wound healing and promotes MΦ pro-healing functions in diabetic wounds. Decreased NPD1 production in diabetic wound is associated with impaired healing. This study identifies a new molecular target that might be useful in development of more effective therapeutics based on NPD1 and syngeneic diabetic MΦs for treatment of diabetic wounds.

Topics: Animals; Cells, Cultured; Diabetes Complications; Diabetes Mellitus, Type 2; Docosahexaenoic Acids; Gene Expression Regulation; Inflammation; Macrophages; Mice; Molecular Structure; Oxidative Stress; Skin; Wound Healing; Wounds and Injuries

Although specialized pro-resolving mediators (SPMs) biosynthesized from polyunsaturated fatty acids are critical for the resolution of acute inflammation, the molecules and pathways that induce their production remain elusive. Here, we show that TLR7, a receptor recognizing viral ssRNA and damaged self-RNA, mobilizes the docosahexaenoic acid (DHA)-derived biosynthetic pathways that lead to the generation of D-series SPMs. In mouse macrophages and human monocytes, TLR7 activation triggered production of DHA-derived monohydroxy metabolome markers and generation of protectin D1 (PD1) and resolvin D1 (RvD1). In mouse allergic airway inflammation, TLR7 activation enhanced production of DHA-derived SPMs including PD1 and accelerated the catabasis of Th2-mediated inflammation. D-series SPMs were critical for TLR7-mediated resolution of airway inflammation as this effect was lost in Alox15(-/-) mice, while resolution was enhanced after local administration of PD1 or RvD1. Together, our findings reveal a new previously unsuspected role of TLR7 in the generation of D-series SPMs and the resolution of allergic airway inflammation. They also identify TLR stimulation as a new approach to drive SPMs and resolution of inflammatory diseases.

Topics: Animals; Arachidonate 12-Lipoxygenase; Arachidonate 15-Lipoxygenase; Arachidonate 5-Lipoxygenase; Bronchoalveolar Lavage Fluid; Cells, Cultured; Docosahexaenoic Acids; Humans; Inflammation; Inflammation Mediators; Macrophages; Mice; Mice, Inbred C57BL; Mice, Knockout; Monocytes; Toll-Like Receptor 7

Docosahexaenoic acid (22:6n-3) is the major brain n-3 polyunsaturated fatty acid and it is possible that docosahexaenoic acid is anti-inflammatory in the brain as it is known to be in other tissues. Using a combination of models including the fat-1 transgenic mouse, chronic dietary n-3 polyunsaturated fatty acid modulation in transgenic and wild-type mice, and acute direct brain infusion, we demonstrated that unesterified docosahexaenoic acid attenuates neuroinflammation initiated by intracerebroventricular lipopolysaccharide. Hippocampal neuroinflammation was assessed by gene expression and immunohistochemistry. Furthermore, docosahexaenoic acid protected against lipopolysaccharide-induced neuronal loss. Acute intracerebroventricular infusion of unesterified docosahexaenoic acid or its 12/15-lipoxygenase product and precursor to protectins and resolvins, 17S-hydroperoxy-docosahexaenoic acid, mimics anti-neuroinflammatory aspects of chronically increased unesterified docosahexaenoic acid. LC-MS/MS revealed that neuroprotectin D1 and several other docosahexaenoic acid-derived specialized pro-resolving mediators are present in the hippocampus. Acute intracerebroventricular infusion of 17S-hydroperoxy-docosahexaenoic acid increases hippocampal neuroprotectin D1 levels concomitant to attenuating neuroinflammation. These results show that unesterified docosahexaenoic acid is protective in a lipopolysaccharide-initiated mouse model of acute neuroinflammation, at least in part, via its conversion to specialized pro-resolving mediators; these docosahexaenoic acid stores may provide novel targets for the prevention and treatment(s) of neurological disorders with a neuroinflammatory component. Our study shows that chronically increased brain unesterified DHA levels, but not solely phospholipid DHA levels, attenuate neuroinflammation. Similar attenuations occur with acute increases in brain unesterified DHA or 17S-HpDHA levels, highlighting the importance of an available pool of precursor unesterified DHA for the production of enzymatically derived specialized pro-resolving mediators that are critical in the regulation of neuroinflammation.

Topics: Animals; Anti-Inflammatory Agents; Carbon Radioisotopes; Diet; Docosahexaenoic Acids; Fatty Acids, Nonesterified; Fatty Acids, Omega-3; Gene Expression Regulation; Hippocampus; Immunohistochemistry; Inflammation; Infusion Pumps, Implantable; Injections, Intraventricular; Lipopolysaccharides; Mass Spectrometry; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Phospholipids

Protectin D1 (PD1) is an anti-inflammatory and proresolving lipid mediator biosynthesized from the omega-3 fatty acid docosahexaenoic acid (DHA). Exogenous PD1 conferred protection against eosinophilic inflammation in animals with experimental asthma, although its endogenous cellular source and functions in human airways are of interest.. We sought to investigate the synthesizing capacity of PD1 in eosinophils from healthy subjects and patients with severe asthma and its direct effects on eosinophil functions.. Human eosinophil-derived metabolites of arachidonic acid and DHA were analyzed with liquid chromatography-tandem mass spectrometry-based lipidomic analysis. The biological activities of PD1 on the function of human eosinophils, including chemotaxis, adhesion molecule expressions, degranulation, superoxide anion generation, or survival, were examined.. We identified PD1 as one of the main anti-inflammatory and proresolving molecules synthesized in human eosinophils. PD1, in nanomolar concentrations, suppressed the chemotaxis induced by CCL11/eotaxin-1 or 5-oxo-eicosatetraenoic acid and modulated the expression of the adhesion molecules CD11b and L-selectin, although it had no effects on the degranulation, superoxide anion generation, or survival of the eosinophils. Compared with the cells harvested from healthy subjects, we observed a prominent decrease in the biosynthesis of PD1 by eosinophils from patients with severe asthma, even in presence of DHA.. These observations are a first indication that activated human eosinophils represent a major source of PD1, which can act as a self-resolving machinery in eosinophilic inflammation, whereas the production of PD1 is impaired in patients with severe asthma.

Topics: Adult; Aged; Anti-Inflammatory Agents; Arachidonic Acids; Asthma; Case-Control Studies; CD11b Antigen; Cell Adhesion Molecules; Chemokine CCL11; Chemotaxis; Docosahexaenoic Acids; Eosinophils; Female; Humans; Inflammation; L-Selectin; Male; Neutrophils; Superoxides

Obesity-induced chronic low-grade inflammation originates from adipose tissue and is crucial for obesity-driven metabolic deterioration, including insulin resistance and type 2 diabetes. Chronic inflammation may be a consequence of a failure to actively resolve inflammation and could result from a lack of local specialized proresolving lipid mediators (SPMs), such as resolvins and protectins, which derive from the n-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We assessed obesity-induced changes of n-3-derived SPMs in adipose tissue and the effects of dietary EPA/DHA thereon. Moreover, we treated obese mice with SPM precursors and investigated the effects on inflammation and metabolic dysregulation. Obesity significantly decreased DHA-derived 17-hydroxydocosahexaenoic acid (17-HDHA, resolvin D1 precursor) and protectin D1 (PD1) levels in murine adipose tissue. Dietary EPA/DHA treatment restored endogenous biosynthesis of n-3-derived lipid mediators in obesity while attenuating adipose tissue inflammation and improving insulin sensitivity. Notably, 17-HDHA treatment reduced adipose tissue expression of inflammatory cytokines, increased adiponectin expression, and improved glucose tolerance parallel to insulin sensitivity in obese mice. These findings indicate that impaired biosynthesis of certain SPM and SPM precursors, including 17-HDHA and PD1, contributes to adipose tissue inflammation in obesity and suggest 17-HDHA as a novel treatment option for obesity-associated complications.

Topics: Adipose Tissue; Animals; Blotting, Western; Docosahexaenoic Acids; Eicosapentaenoic Acid; Flow Cytometry; Humans; Immunohistochemistry; Inflammation; Male; Mice; Mice, Inbred C57BL; Obesity; Reverse Transcriptase Polymerase Chain Reaction

Acute inflammation in healthy individuals is self-limiting and has an active termination program. The mechanisms by which acute inflammation is resolved are of interest. In murine zymosan-induced peritonitis, we found that eosinophils are recruited to the inflamed loci during the resolution phase of acute inflammation. In vivo depletion of eosinophils caused a resolution deficit, namely impaired lymphatic drainage with reduced appearance of phagocytes carrying engulfed zymosan in the draining lymph node, and sustained numbers of polymorphonuclear leukocytes in inflamed tissues. Liquid chromatography-tandem mass spectrometry-based lipidomics of the resolving exudates revealed that locally activated eosinophils in the resolution phase produced proresolving mediators, including protectin D1 (PD1) from docosahexaenoic acid. The resolution deficit caused by eosinophil depletion was rescued by eosinophil restoration or the administration of PD1. Eosinophils deficient in 12/15-lipoxygenase could not rescue the resolution phenotype. The present results indicate that mouse eosinophils and eosinophil-derived lipid mediators, including PD1, have a role in promoting the resolution of acute inflammation, expanding the roles of eosinophils in host defense and resolution.

Topics: Animals; Arachidonate 12-Lipoxygenase; Arachidonate 15-Lipoxygenase; Docosahexaenoic Acids; Eosinophils; Inflammation; Male; Mice; Mice, Inbred C57BL; Peritonitis; Time Factors; Zymosan

Mechanisms of inflammatory pain are not fully understood. We investigated the role of TRPV1 (transient receptor potential subtype V1) and TNF-α, two critical mediators for inflammatory pain, in regulating spinal cord synaptic transmission. We found in mice lacking Trpv1 the frequency but not the amplitude of spontaneous EPSCs (sEPSCs) in lamina II neurons of spinal cord slices is reduced. Further, C-fiber-induced spinal long-term potentiation (LTP) in vivo is abolished in Trpv1 knock-out mice. TNF-α also increases sEPSC frequency but not amplitude in spinal outer lamina II (lamina IIo) neurons, and this increase is abolished in Trpv1 knock-out mice. Single-cell PCR analysis revealed that TNF-α-responding neurons in lamina IIo are exclusively excitatory (vGluT2(+)) neurons. Notably, neuroprotectin-1 (NPD1), an anti-inflammatory lipid mediator derived from ω-3 polyunsaturated fatty acid (docosahexaenoic acid), blocks TNF-α- and capsaicin-evoked sEPSC frequency increases but has no effect on basal synaptic transmission. Strikingly, NPD1 potently inhibits capsaicin-induced TRPV1 current (IC(50) = 0.4 nm) in dissociated dorsal root ganglion neurons, and this IC(50) is ≈ 500 times lower than that of AMG9810, a commonly used TRPV1 antagonist. NPD1 inhibition of TRPV1 is mediated by GPCRs, since the effects were blocked by pertussis toxin. In contrast, NPD1 had no effect on mustard oil-induced TRPA1 currents. Spinal injection of NPD1, at very low doses (0.1-10 ng), blocks spinal LTP and reduces TRPV1-dependent inflammatory pain, without affecting baseline pain. NPD1 also reduces TRPV1-independent but TNF-α-dependent pain hypersensitivity. Our findings demonstrate a novel role of NPD1 in regulating TRPV1/TNF-α-mediated spinal synaptic plasticity and identify NPD1 as a novel analgesic for treating inflammatory pain.

Topics: 6-Cyano-7-nitroquinoxaline-2,3-dione; Acrylamides; Analysis of Variance; Animals; Bridged Bicyclo Compounds, Heterocyclic; Cells, Cultured; Disease Models, Animal; Docosahexaenoic Acids; Enzyme Inhibitors; Excitatory Amino Acid Antagonists; Excitatory Postsynaptic Potentials; Freund's Adjuvant; Ganglia, Spinal; In Vitro Techniques; Inflammation; Long-Term Potentiation; Mice; Mice, Inbred C57BL; Mice, Knockout; Neurons; Pain; Pain Measurement; Patch-Clamp Techniques; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; Spinal Cord; TRPV Cation Channels; Tumor Necrosis Factor-alpha

Retinal pigment epithelial (RPE) cells are the most restrictive layer of the three components of the outer Blood-Retina Barrier, preventing the passage of biomolecules in relation to size and charge and thus preserving a controlled environment for the photoreceptors. The retinal pigment epithelium is a tight structure that, when disrupted as a cause or consequence of pathological conditions, deeply affects the neural retina. Since adult human RPE cells are not replicative cells, their preservation is of major interest for the biomedical field due to their loss in many retino-degenerative pathologies. There are several triggers that elicit reactive oxygen species (ROS) formation in normal and pathological circumstances. When the production of these species overwhelms the scavenging and detoxifying systems, their activity results in programmed cell death. Docosahexaenoic acid (DHA) is an essential lipid that is conspicuously accumulated in photoreceptors and RPE cells in the retina. DHA and its oxygenation product, neuroprotectin D1 (NPD1), are major players in the protection of these cells and the retina. NPD1 promotes the synthesis of anti-apoptotic proteins of certain members of the Bcl-2 family and blocks the expression of pro-inflammatory proteins like cyclooxygenase-2.

Topics: Apoptosis; Cell Death; Cell Survival; Cytoprotection; Docosahexaenoic Acids; Humans; Inflammation; Oxidative Stress; Retinal Degeneration; Retinal Pigment Epithelium; Signal Transduction

Atherosclerosis is a complex disease process in which genetic, lipid, cellular, and immunological factors combine to determine the location, severity, and timing of lesion development and clinical events. It has been demonstrated, however, that inflammation governed atherosclerosis during the course of development of atherosclerosis. It has also been demonstrated to be effective to decrease the cardiovascular events and improve the prognosis of atherosclerotic diseases by regulating inflammatory reaction (e.g., statins). However, endogenous mechanisms of limiting inflammation in atherosclerosis are still unclear. Recent studies showed that lipoxidase/leukotrienes (LOX/LTs) pathway played important role in the ignition and development of atherosclerosis, whereas resolvins (E-series resolvins and D-series resolvins) and protectins [protectin D1 (PD1) and neuroprotectin D1 (NPD1)], endogenous lipid-derived mediators, inhibited inflammation through pro-resolution and counter-modulating immune inflammation reaction in atherosclerosis. Hence, we hypothesize that increased endogenous lipid mediators mentioned above play a vital role in anti-atherosclerosis and plaque stabilization through pro-resolution and anti-inflammation by LOX/LTs pathway. In addition, we predict that the endogenous lipid mediators may be a new target for treatment of atherosclerotic diseases.

Topics: Animals; Anti-Inflammatory Agents; Atherosclerosis; Dietary Supplements; Docosahexaenoic Acids; Fatty Acids, Omega-3; Humans; Immune System; Inflammation; Inflammation Mediators; Lipids; Models, Biological; Models, Theoretical

The surface of the eye actively suppresses inflammation while maintaining a remarkable capacity for epithelial wound repair. Our understanding of mechanisms that balance inflammatory/reparative responses to provide effective host defense while preserving tissue function is limited, in particular, in the cornea. Lipoxin A(4) (LXA(4)) and docosahexaenoic acid-derived neuroprotectin D1 (NPD1) are lipid autacoids formed by 12/15-lipoxygenase (LOX) pathways that exhibit anti-inflammatory and neuroprotective properties. Here, we demonstrate that mouse corneas generate endogenous LXA(4) and NPD1. 12/15-LOX (Alox15) and LXA(4) receptor mRNA expression as well as LXA(4) formation were abrogated by epithelial removal and restored during wound healing. Amplification of these pathways by topical treatment with LXA(4) or NPD1 (1 microg) increased the rate of re-epithelialization (65-90%, n = 6-10, p < 0.03) and attenuated the sequelae of thermal injury. In contrast, the proinflammatory eicosanoids, LTB(4) and 12R-hydroxyeicosatrienoic acid, had no impact on corneal re-epithelialization. Epithelial removal induced a temporally defined influx of neutrophils into the stroma as well as formation of the proinflammatory chemokine KC. Topical treatment with LXA(4) and NPD1 significantly increased PMNs in the cornea while abrogating KC formation by 60%. More importantly, Alox15-deficient mice exhibited a defect in both corneal re-epithelialization and neutrophil recruitment that correlated with a 43% reduction in endogenous LXA(4) formation. Collectively, these results identify a novel action for the mouse 12/15-LOX (Alox15) and its products, LXA(4) and NPD1, in wound healing that is distinct from their well established anti-inflammatory properties.

Topics: Animals; Anti-Inflammatory Agents; Arachidonate 12-Lipoxygenase; Arachidonate 15-Lipoxygenase; Chemokines; Chromatography, High Pressure Liquid; Cornea; Docosahexaenoic Acids; Eicosanoids; Epithelial Cells; Epithelium; Gas Chromatography-Mass Spectrometry; Hot Temperature; Hydroxyeicosatetraenoic Acids; Inflammation; Leukocytes; Leukotriene B4; Lipid Metabolism; Mice; Mice, Inbred BALB C; Models, Chemical; Neutrophils; Phenotype; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Ultraviolet Rays; Wound Healing

Docosahexaenoic acid, a major omega-3 fatty acid in human brain, synapses, retina, and other neural tissues, displays beneficial actions in neuronal development, cancer, and inflammatory diseases by mechanisms that remain to be elucidated. In this study we found, using lipid mediator informatics employing liquid chromatography-tandem mass spectrometry, that (10,17S)-docosatriene/neuroprotectin D1, now termed protectin D1 (PD1), is generated from docosahexaenoic acid by T helper type 2-skewed peripheral blood mononuclear cells in a lipoxygenase-dependent manner. PD1 blocked T cell migration in vivo, inhibited tumor necrosis factor alpha and interferon-gamma secretion, and promoted apoptosis mediated by raft clustering. These results demonstrated novel anti-inflammatory roles for PD1 in regulating events associated with inflammation and resolution.

Topics: Animals; Apoptosis; Arachidonate 15-Lipoxygenase; Brain; Chromatography, Liquid; Cytokines; Docosahexaenoic Acids; Dose-Response Relationship, Drug; Humans; In Situ Nick-End Labeling; Inflammation; Interferon-gamma; Leukocytes, Mononuclear; Male; Mass Spectrometry; Membrane Microdomains; Mice; Models, Chemical; Oxidative Stress; Peritonitis; T-Lymphocytes; Time Factors; Tumor Necrosis Factor-alpha; Zymosan