Monocyte phospholipase a2

Matrix metalloproteinases (MMPs) are proteolytic enzymes that have been associated with the pathogenesis of inflammatory diseases and obesity. Adipose tissue in turn is an active endocrine organ capable of secreting a range of proinflammatory mediators with autocrine and paracrine properties, which contribute to the inflammation of adipose tissue and adjacent tissues. However, the potential inflammatory effects of MMPs in adipose tissue cells are still unknown. This study investigates the effects of BmooMPα-I, a single-domain snake venom metalloproteinase (SVMP), in activating an inflammatory response by 3T3-L1 preadipocytes in culture, focusing on prostaglandins (PGs), cytokines, and adipocytokines biosynthesis and mechanisms involved in prostaglandin E2 (PGE2 ) release...

Importance: Cardiovascular disease (CVD) is increased among people with HIV (PWH), but little is known regarding the prevalence and extent of coronary artery disease (CAD) and associated biological factors in PWH with low to moderate traditional CVD risk. Objectives: To determine unique factors associated with CVD in PWH and to assess CAD by coronary computed tomography angiography (CTA) and critical pathways of arterial inflammation and immune activation. Design, Setting, and Participants: This cohort study among male and female PWH, aged 40 to 75 years, without known CVD, receiving stable antiretroviral therapy, and with low to moderate atherosclerotic cardiovascular disease (ASCVD) risk according to the 2013 American College of Cardiology/American Heart Association pooled cohort equation, was part of the Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE), a large, ongoing primary prevention trial of statin therapy among PWH conducted at 31 US sites...

We previously showed that injection of recombinant human group IIA secreted phospholipase A2 (hGIIA sPLA2 ) to Plasmodium chabaudi-infected mice lowers parasitaemia by 20%. Here, we show that transgenic (TG) mice overexpressing hGIIA sPLA2 have a peak of parasitaemia about 30% lower than WT littermates. During infection, levels of circulating sPLA2 , enzymatic activity and plasma lipid peroxidation were maximal at day-14, the peak of parasitaemia. Levels of hGIIA mRNA increased in liver but not in spleen and blood cells, suggesting that liver may contribute as a source of circulating hGIIA sPLA2 ...

Macrophage polarization is a dynamic and integral process in tissue inflammation and remodeling. In this study, we describe that lipoprotein-associated phospholipase A2 (Lp-PLA2 ) plays an important role in controlling inflammatory macrophage (M1) polarization in rodent experimental autoimmune encephalomyelitis (EAE) and in monocytes from multiple sclerosis (MS) patients. Specific inhibition of Lp-PLA2 led to an ameliorated EAE via markedly decreased inflammatory and demyelinating property of M1. The effects of Lp-PLA2 on M1 function were mediated by lysophosphatidylcholine, a bioactive product of oxidized lipids hydrolyzed by Lp-PLA2 through JAK2-independent activation of STAT5 and upregulation of IRF5...

AIMS: It was suggested that group V secretory phospholipase A2 (sPLA2-V) existed in the nucleus. This study examined whether nuclear sPLA2 -V plays a role in endocytosis of acetylated low-density lipoprotein (AcLDL) in monocyte/macrophage-like cell line RAW264.7 cells. METHODS: RAW264.7 cells were transfected with shRNA vector targeting sPLA2 -V (sPLA2 -V-knockdown [KD] cells) or empty vector (sPLA2 -V-wild-type [WT] cells). AcLDL endocytosis was assessed by incubation with 125 I-AcLDL or AcLDL conjugated with pHrodo...

Hydrogen sulfide (H2 S) exerts an anti‑atherosclerotic effect and decreases foam cell formation. Lipoprotein‑associated phospholipase A2 (Lp‑PLA2 ) is a key factor involved in foam cell formation. However, the association between H2 S and Lp‑PLA2 expression levels with respect to foam cell formation has not yet been elucidated. The present study investigated whether H2 S can affect foam cell formation and potential signalling pathways via regulation of the expression and activity of Lp‑PLA2 . Using human monocytic THP‑1 cells as a model system, it was observed that oxidized low‑density lipoprotein (ox‑LDL) not only upregulates the expression level and activity of Lp‑PLA2 , it also downregulates the expression level and activity of Cystathionine γ lyase...

Macrophages are professional antigen presenting cells with intense phagocytic activity, strategically distributed in tissues and cavities. These cells are capable of responding to a wide variety of innate inflammatory stimuli, many of which are signaled by lipid mediators. The distribution of arachidonic acid (AA) among glycerophospholipids and its subsequent release and conversion into eicosanoids in response to inflammatory stimuli such as zymosan, constitutes one of the most studied models. In this work, we used liquid and/or gas chromatography coupled to mass spectrometry to study the changes in the levels of membrane glycerophospholipids of mouse peritoneal macrophages and the implication of group IVA cytosolic phospholipase A2 (cPLA2 α) in the process...

Muscle tissue damage is one of the local effects described in bothropic envenomations. Bothropstoxin-I (BthTX-I), from B. jararacussu venom, is a K49-phospholipase A2 that induces a massive muscle tissue injury, and, consequently, local inflammatory reaction. The NLRP3 inflammasome is a sensor that triggers inflammation by activating caspase 1 and releasing IL-1b and/or inducing pyroptotic cell death in response to tissue damage. We, therefore, aimed to address activation of NLRP3 inflammasome by BthTX-I-associated injury and the mechanism involved in this process...

Arachidonic acid (AA) is a polyunsaturated fatty acid present at high concentrations in the ovarian cancer (OC) microenvironment and associated with a poor clinical outcome. In the present study, we have unraveled a potential link between AA and macrophage functions. Methods: AA-triggered signal transduction was studied in primary monocyte-derived macrophages (MDMs) by phosphoproteomics, transcriptional profiling, measurement of intracellular Ca2+ accumulation and reactive oxygen species production in conjunction with bioinformatic analyses...

The ion channels Piezo1 and TRPV4 have both, independently, been implicated in high venous pressure- and fluid shear stress-induced vascular hyperpermeability in endothelial cells.  However, the mechanism by which Piezo1 and TRPV4 channels execute the same function is poorly understood.  Here we demonstrate that Piezo1 regulates TRPV4 channel activation in endothelial cells and that Piezo1-mediated TRPV4 channel opening is a function of the strength and duration of fluid shear stress.  We first confirmed that either fluid shear stress or the Piezo1 agonist, Yoda1, led to an elevation in intracellular calcium ([Ca2+]i), and that application of the Piezo1 antagonist, GsMTx4, completely blocked this change...

Positional isomers of hexadecenoic acid are considered as fatty acids with anti-inflammatory properties. The best known of them, palmitoleic acid (cis-9-hexadecenoic acid, 16:1n-7), has been identified as a lipokine with important beneficial actions in metabolic diseases. Hypogeic acid (cis-7-hexadecenoic acid, 16:1n-9) has been regarded as a possible biomarker of foamy cell formation during atherosclerosis. Notwithstanding the importance of these isomers as possible regulators of inflammatory responses, very little is known about the regulation of their levels and distribution and mobilization among the different lipid pools within the cell...

Several studies have confirmed that the myeloid-derived suppressor cells (MDSCs) are closely associated with autoimmune diseases, but their exact role in these processes remains largely unclear. Here, we investigated the role MDSCs in patients with primary membranous nephropathy (PMN). Compared to healthy controls (HCs), PMN patients showed significantly increased number of HLA-DR- CD11b+ CD33+ MDSCs in the peripheral blood, including both CD14+ CD66b- monocytic and CD14- CD66b+ granulocytic MDSCs. The frequency of MDSCs was positively correlated with the level of serum anti-phospholipase A2 receptor (anti-PLA2R), 24-h urine protein quantification, and disease activity in PMN patients...

OBJECTIVE: To assess the effect of HIV infection and combined antiretroviral therapy (c-ART) on various proatherogenic biomarkers and lipids and to investigate their relationship with subclinical atherosclerosis in a cohort of treatment-naive HIV-infected patients. METHODS: We performed a prospective, comparative, multicenter study of 2 groups of treatment-naive HIV-infected patients (group A, CD4>500 cells/μL, not starting c-ART; and group B, CD4<500 cells/μL, starting c-ART at baseline) and a healthy control group...

Behçet's disease (BD) is a relapsing, multisystem and inflammatory condition characterized by systemic vasculitis of small and large vessels. Although the etiopathogenesis of BD remains unknown, immune-mediated mechanisms play a major role in the development of the disease. BD patients present leukocyte infiltration in the mucocutaneous lesions as well as neutrophil hyperactivation. In contrast to neutrophils, whose involvement in the pathogenesis of BD has been extensively studied, the biology of monocytes during BD is less well known...

Mycobacterium tuberculosis ( M.tb ) infection results in approximately 1.3 million human deaths each year. M.tb resides primarily inside macrophages, and maintains persistent infection. In response to infection and inflammation, platelet activating factor C-16 (PAF C-16), a phospholipid compound, is released by various cells including neutophils and monocytes. We have recently shown that PAF C-16 can directly inhibit the growth of two representative non-pathogenic mycobacteria, Mycobacterium bovis BCG and Mycobacterium smegmatis ( M...

Phospholipase A2 s constitute a wide group of lipid-modifying enzymes which display a variety of functions in innate immune responses. In this work, we utilized mass spectrometry-based lipidomic approaches to investigate the action of Asp-49 Ca2+ -dependent secreted phospholipase A2 (sPLA2 ) (MT-III) and Lys-49 sPLA2 (MT-II), two group IIA phospholipase A2 s isolated from the venom of the snake Bothrops asper , on human peripheral blood monocytes. MT-III is catalytically active, whereas MT-II lacks enzyme activity...

The bioactive sphingolipid ceramide 1-phosphate (C1P) regulates key physiologic cell functions and is implicated in a number of metabolic alterations and pathological processes. Initial studies using different types of fibroblasts and monocytes/macrophages revealed that C1P was mitogenic and that it promoted cell survival through inhibition of apoptosis. Subsequent studies implicated C1P in inflammatory responses with a specific role as pro-inflammatory agent. Specifically, C1P potently stimulated cytosolic phospholipase A2 (cPLA2 ) resulting in elevation of arachidonic acid and pro-inflammatory eicosanoid levels...

People with HIV (PWH) have an increased prevalence of cardiovascular disease (CVD) compared to uninfected patients. Lipoprotein-associated phospholipase A2 (Lp-PLA2 ) catalyzes the synthesis of pro-inflammatory lipids that recruit monocytes. Current guidelines for assessing cardiovascular risk in HIV-infected patients suggest that Lp-PLA2 may be a useful surrogate marker for CVD health in this patient population. Lipoprotein-associated phospholipase A2 , lipids, glucose, physical parameters, and carotid intimal-medial thickness (CIMT) were measured in 98 participants (49 HIV-uninfected, 27 antiretroviral therapy [ART]-naive PWH, and 22 ART-treated PWH)...

Nonalcoholic steatohepatitis (NASH) is a lifestyle-related disease characterized by hepatic fibrosis with the accumulation of fat and inflammation and can progress to cirrhosis or hepatocellular carcinoma. However, effective pharmacotherapeutic strategies for hepatic fibrosis in NASH remain to be established. Among the initiators of inflammation, we have been investigating the possible involvement of group IVA phospholipase A2 (IVA-PLA2 ), which catalyzes the initial step in the generation of lipid mediators, including eicosanoids and lysophospholipids, in the progression of hepatic fibrosis...

Introduction: Lipid mediators (LMs) comprise bioactive metabolites of polyunsaturated fatty acids, including pro-inflammatory prostaglandins (PGs), thromboxanes (TXs), and leukotrienes (LTs), as well as specialized pro-resolving mediators (SPMs). They are essentially biosynthesized via cyclooxygenase (COX) and lipoxygenase (LO) pathways in complex networks and regulate the progression as well as the resolution of inflammatory disorders including inflammation-triggered cancer. Ginkgolic acid (GA) is a phenolic acid contained in Ginkgo biloba L...