lipoxin-b4 and Inflammation

Metabolomics enables a systems approach to interrogate the bioactive mediators, their pathways and further metabolites involved in the physiology and pathophysiology of human and animal tissues. New metabololipidomic approaches with mass spectrometry presented in this brief review can now be utilized for the identification and profiling of lipid mediator networks that control inflammation-resolution in human blood and healthy and diseased solid tissues. Coagulation of blood is a protective response that prevents excessive bleeding on injury of blood vessels. Here, we review novel approaches to understand the relationship(s) between coagulation and resolution of inflammation and infection. To determine whether coagulation is involved in host-protective actions by lipid mediators, we used a metabololipidomic-based profiling approach with human whole blood (WB) during coagulation. We identified recently temporal clusters of endogenously produced pro-thrombotic and proinflammatory lipid mediators (eicosanoids), as well as specialized proresolving mediators (SPMs) in this vital process. In addition to the classic eicosanoids (prostaglandins, thromboxanes and leukotrienes), a specific SPM cluster was identified that consists of resolvin E1 (RvE1), RvD1, RvD5, lipoxin B

Topics: Animals; Chromatography, Liquid; Eicosanoids; Humans; Inflammation; Lipid Metabolism; Lipids; Lipoxins; Metabolomics; Tandem Mass Spectrometry

Topics: Apoptosis; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Kinetics; Leukocytes; Lipoxins; Neutrophils; Phagocytes; Signal Transduction

Eicosanoids are known to play important roles in cell-cell communications and as intracellular signals that are critical components of multi-cellular responses such as acute inflammation and reperfusion injury. Recent findings have given rise to several new concepts that are reviewed here regarding the generation of eicosanoids and their impact in inflammation. Lipoxins (LX) are trihydroxytetraene-containing eicosanoids that can be generated within the vascular lumen during platelet-leukocyte interactions and at mucosal surfaces via leukocyte-epithelial cell interactions. During these cell-cell interactions, transcellular biosynthetic pathways are used as major LX biosynthetic routes, and thus, in humans, LX are formed in vivo during multi-cellular responses such as inflammation, atherosclerosis, and in asthma. This branch of the eicosanoid cascade generates specific tetraene-containing products that serve as stop signals, in that they regulate key steps in leukocyte trafficking and prevent leukocyte-mediated acute tissue injury. Of interest here are recent results indicating that aspirin's mechanism of action also involves the triggering of novel carbon 15 epimers of LX or 15-epi-LX that mimic the bioactions of native LX. Here, an overview of these recent developments is presented, with a focus on the cellular and molecular interactions of these novel antiinflammatory lipid mediators.

Topics: Animals; Arachidonate 5-Lipoxygenase; Aspirin; Eicosanoids; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Lipoxins; Neutrophils; Receptors, Leukotriene B4; Signal Transduction

Chronic inflammation is now widely recognized to play important roles in many commonly occurring diseases, including COVID-19. The resolution response to this chronic inflammation is an active process governed by specialized pro-resolving mediators (SPMs) like the lipid mediators known as lipoxins. The biosynthesis of lipoxins is catalyzed by several lipoxygenases (LOXs) from arachidonic acid. However, the molecular details of the mechanisms involved are not well known yet. In this paper, we have combined molecular dynamics (MD) simulations and quantum mechanics/molecular mechanics (QM/MM) calculations to analyze how reticulocyte 15-LOX-1 catalyzes the production of lipoxins from 5(

Topics: Arachidonate 15-Lipoxygenase; Biosynthetic Pathways; Catalysis; COVID-19; Humans; Inflammation; Leukotrienes; Lipid Peroxides; Lipoxins; Models, Molecular; Molecular Docking Simulation; Molecular Dynamics Simulation; Oxygen; Quantum Theory; Reticulocytes

Tendon stromal cells isolated from patients with chronic shoulder rotator cuff tendon tears have dysregulated resolution responses. Current therapies do not address the biological processes concerned with persistent tendon inflammation; therefore, new therapeutic approaches that target tendon stromal cells are required. We examined whether two specialized proresolving mediators (SPMs), lipoxin B4 (LXB4) and resolvin E1 (RvE1), modulate the bioactive lipid mediator profiles of IL-1β-stimulated tendon cells derived from patients with shoulder tendon tears and healthy volunteers. We also examined whether LXB4 or RvE1 treatments moderated the proinflammatory phenotype of tendon tear stromal cells. Incubation of IL-1β-treated patient-derived tendon cells in LXB4 or RvE1 up-regulated concentrations of SPMs. RvE1 treatment of diseased tendon stromal cells increased 15-epi-LXB4 and regulated postaglandin F2α. LXB4 or RvE1 also induced expression of the SPM biosynthetic enzymes 12-lipoxygenase and 15-lipoxygenase. RvE1 treatment up-regulated the proresolving receptor human resolvin E1 compared with vehicle-treated cells. Incubation in LXB4 or RvE1 moderated the proinflammatory phenotype of patient-derived tendon tear cells, regulating markers of tendon inflammation, including podoplanin, CD90, phosphorylated signal transducer and activator of transcription 1, and IL-6. LXB4 and RvE1 counterregulate inflammatory processes in tendon stromal cells, supporting the role of these molecules as potential therapeutics to resolve tendon inflammation.

Topics: Aged; Anti-Inflammatory Agents; Cells, Cultured; Eicosapentaenoic Acid; Female; Humans; Inflammation; Inflammation Mediators; Lacerations; Lipoxins; Male; Middle Aged; Shoulder; Shoulder Injuries; Shoulder Joint; Stromal Cells; Tendon Injuries; Tendons

This commentary highlights the article by Dakin et al that demonstrates critical roles of bioactive lipids in the resolution of inflammation in shoulder tendon tears.

Topics: Eicosapentaenoic Acid; Humans; Inflammation; Lipids; Lipoxins; Rotator Cuff Injuries; Shoulder; Stromal Cells; Tendon Injuries; Tendons

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

Thiazolidinediones exert their antidiabetic effect in part by ameliorating chronic inflammation in adipose tissue. However, the precise mechanism of this anti-inflammatory action has remained unclear. We here investigated the effects of the TZD pioglitazone on the lipid mediator profile of adipose tissue in obese diabetic KKAy mice by metabololipidomics analysis based on liquid chromatography and tandem mass spectrometry. Pioglitazone treatment increased the amounts of pro-resolving lipid mediators including lipoxin B

Topics: 3T3-L1 Cells; Adipocytes; Adipose Tissue; Animals; Chronic Disease; Cytokines; Diabetes Mellitus, Type 2; Gene Expression Profiling; Hypoglycemic Agents; Inflammation; Lipid Metabolism; Lipoxins; Male; Mice; Mice, Obese; Obesity; Pioglitazone

Chronic mucosal inflammation is the hallmark of important and common airway diseases, such as allergic rhinitis (AR) and asthma. Lipoxin A4 (LXA4) is an endogenous pro-resolving mediator for mucosal inflammation that decreases allergic and asthmatic responses. Lipoxin B4 (LXB4) is a structurally distinct member of the lipoxin family that signals in a manner distinct from LXA4. LXB4 is generated by mucosal tissues, but its actions in allergic inflammation are unknown. Here, we used murine models of AR and asthma to investigate LXB4's activity in mucosal inflammation. In the upper airway, LXB4 significantly decreased nasal mucosal leukocytes and degranulation of mast cells (MCs) and eosinophils. In the lower airway, LXB4 significantly decreased airway inflammation, mucus metaplasia, and hyper-responsiveness. Inhibition of MC degranulation in vivo by LXB4 was more potent than dexamethasone, and these agents displayed unique profiles for cytokine regulation; however, their overall anti-inflammatory actions were comparable. LXB4 decreased eotaxin-dependent eosinophil chemotaxis, IgE-mediated MC degranulation, and expression of type 2 cytokine receptors. Together, these findings indicate that LXB4 carries cell type selective and mucosal protective actions that broaden the lipoxin family's therapeutic potential for upper and lower airway catabasis.

Topics: Animals; Cell Degranulation; Chemotaxis, Leukocyte; Cytokines; Disease Models, Animal; Eosinophils; Female; Immunoglobulin E; Inflammation; Leukocytes; Lipoxins; Lung; Male; Mast Cells; Mice; Mucus; Nasal Mucosa; Respiratory Hypersensitivity