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Polyunsaturated fatty acids and fatty acid-derived lipid mediators: Recent advances in the understanding of their biosynthesis, structures, and functions.
Dyall, SC, Balas, L, Bazan, NG, Brenna, JT, Chiang, N, da Costa Souza, F, Dalli, J, Durand, T, Galano, JM, Lein, PJ, et al
Progress in lipid research. 2022;:101165
Abstract
Polyunsaturated fatty acids (PUFAs) are structural components of membrane phospholipids, and influence cellular function via effects on membrane properties, and also by acting as a precursor pool for lipid mediators. These lipid mediators are formed via activation of pathways involving at least one step of dioxygen-dependent oxidation, and are consequently called oxylipins. Their biosynthesis can be either enzymatically-dependent, utilising the promiscuous cyclooxygenase, lipoxygenase, or cytochrome P450 mixed function oxidase pathways, or nonenzymatic via free radical-catalyzed pathways. The oxylipins include the classical eicosanoids, comprising prostaglandins, thromboxanes, and leukotrienes, and also more recently identified lipid mediators. With the advent of new technologies there is growing interest in identifying these different lipid mediators and characterising their roles in health and disease. This review brings together contributions from some of those at the forefront of research into lipid mediators, who provide brief introductions and summaries of current understanding of the structure and functions of the main classes of nonclassical oxylipins. The topics covered include omega-3 and omega-6 PUFA biosynthesis pathways, focusing on the roles of the different fatty acid desaturase enzymes, oxidized linoleic acid metabolites, omega-3 PUFA-derived specialized pro-resolving mediators, elovanoids, nonenzymatically oxidized PUFAs, and fatty acid esters of hydroxy fatty acids.
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Neutrophil Resolvin E1 Receptor Expression and Function in Type 2 Diabetes.
Freire, MO, Dalli, J, Serhan, CN, Van Dyke, TE
Journal of immunology (Baltimore, Md. : 1950). 2017;(2):718-728
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Abstract
Unresolved inflammation is key in linking metabolic dysregulation and the immune system in type 2 diabetes. Successful regulation of acute inflammation requires biosynthesis of specialized proresolving lipid mediators, such as E-series resolvin (RvE) 1, and activation of cognate G protein-coupled receptors. RvE1 binds to leukotriene B4 (BLT-1) on neutrophils and to ERV-1/ChemR23 on monocyte/macrophages. We show novel actions of RvE1 and expression patterns of neutrophil receptors in type 2 diabetes. Neutrophils from healthy subjects express functional BLT-1, low levels of minimally functional ERV-1, and inversed coexpression when compared to neutrophils from type 2 diabetes subjects. Stimulation with TNF-α or LPS increased the expression of ERV-1 by healthy and diabetic neutrophils. RvE1 counteracted LPS and TNF-α induction of ERV-1 overexpression and endogenous diabetic overexpression, activating phagocytosis and resolution signals. Functional ERV-1 was determined by phosphorylation of the signaling protein ribosomal S6. Receptor-antagonism experiments revealed that the increase in phosphorylation of ribosomal S6 was mediated by BLT-1 in healthy subject neutrophils and by ERV-1 in diabetes. Metabololipidomics reveal a proinflammatory profile in diabetic serum. Cell phagocytosis is impaired in type 2 diabetes and requires RvE1 for activation. The dose of RvE1 required to activate resolution signals in type 2 diabetic neutrophils was significantly higher than in healthy controls. RvE1 rescues the dysregulation seen on neutrophil receptor profile and, following a therapeutic dosage, activates phagocytosis and resolution signals in type 2 diabetes. These findings reveal the importance of resolution receptors in health, disease, and dysregulation of inflammation in type 2 diabetes.
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Human Sepsis Eicosanoid and Proresolving Lipid Mediator Temporal Profiles: Correlations With Survival and Clinical Outcomes.
Dalli, J, Colas, RA, Quintana, C, Barragan-Bradford, D, Hurwitz, S, Levy, BD, Choi, AM, Serhan, CN, Baron, RM
Critical care medicine. 2017;(1):58-68
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Abstract
OBJECTIVE To identify and measure recently described chemical mediators, termed specialized pro-resolving mediators that actively regulate the resolution of acute-inflammation, and correlate measurements with clinical outcomes. DESIGN Herein, deidentified plasma was collected from sepsis patients (n = 22 subjects) within 48 hours of admission to the ICU and on days 3 and 7 thereafter and subjected to lipid mediator profiling. SETTING Brigham and Women's Hospital Medical Intensive Care Unit. SUBJECTS Patients in the medical ICU with sepsis. MEASUREMENTS AND MAIN RESULTS In all patients, we identified more than 30 bioactive mediators and pathway markers in peripheral blood using established criteria for arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid metabolomes. These included inflammation initiating mediators leukotriene B4 and prostaglandin E2 and pro-resolving mediators resolvin D1, resolvin D2, and protectin D1. In sepsis nonsurvivors, we found significantly higher inflammation-initiating mediators including prostaglandin F2α and leukotriene B4 and pro-resolving mediators, including resolvin E1, resolvin D5, and 17R-protectin D1 than was observed in surviving sepsis subjects. This signature was present at ICU admission and persisted for 7 days. Further analysis revealed increased respiratory failure in nonsurvivors. Higher inflammation-initiating mediators (including prostaglandin F2α) and select proresolving pathways were associated with the development of acute respiratory distress syndrome, whereas other traditional clinical indices were not predictive of acute respiratory distress syndrome development. CONCLUSIONS These results provide peripheral blood lipid mediator profiles in sepsis that correlate with survival and acute respiratory distress syndrome development, thus suggesting plausible novel biomarkers and biologic targets for critical illness.
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Plasma metabolomics in human pulmonary tuberculosis disease: a pilot study.
Frediani, JK, Jones, DP, Tukvadze, N, Uppal, K, Sanikidze, E, Kipiani, M, Tran, VT, Hebbar, G, Walker, DI, Kempker, RR, et al
PloS one. 2014;(10):e108854
Abstract
We aimed to characterize metabolites during tuberculosis (TB) disease and identify new pathophysiologic pathways involved in infection as well as biomarkers of TB onset, progression and resolution. Such data may inform development of new anti-tuberculosis drugs. Plasma samples from adults with newly diagnosed pulmonary TB disease and their matched, asymptomatic, sputum culture-negative household contacts were analyzed using liquid chromatography high-resolution mass spectrometry (LC-MS) to identify metabolites. Statistical and bioinformatics methods were used to select accurate mass/charge (m/z) ions that were significantly different between the two groups at a false discovery rate (FDR) of q<0.05. Two-way hierarchical cluster analysis (HCA) was used to identify clusters of ions contributing to separation of cases and controls, and metabolomics databases were used to match these ions to known metabolites. Identity of specific D-series resolvins, glutamate and Mycobacterium tuberculosis (Mtb)-derived trehalose-6-mycolate was confirmed using LC-MS/MS analysis. Over 23,000 metabolites were detected in untargeted metabolomic analysis and 61 metabolites were significantly different between the two groups. HCA revealed 8 metabolite clusters containing metabolites largely upregulated in patients with TB disease, including anti-TB drugs, glutamate, choline derivatives, Mycobacterium tuberculosis-derived cell wall glycolipids (trehalose-6-mycolate and phosphatidylinositol) and pro-resolving lipid mediators of inflammation, known to stimulate resolution, efferocytosis and microbial killing. The resolvins were confirmed to be RvD1, aspirin-triggered RvD1, and RvD2. This study shows that high-resolution metabolomic analysis can differentiate patients with active TB disease from their asymptomatic household contacts. Specific metabolites upregulated in the plasma of patients with active TB disease, including Mtb-derived glycolipids and resolvins, have potential as biomarkers and may reveal pathways involved in TB disease pathogenesis and resolution.