Reduced plasma extracellular vesicle CD5L content in patients with acute-on-chronic liver failure: interplay with specialized pro-resolving lipid mediators.

Acute-on chronic liver failure (ACLF) is a syndrome that develops in patients with acutely decompensated cirrhosis (AD). It is characterized by a systemic hyperinflammatory state, leading to multiple organ failure. Our objective was to analyze macrophage anti-inflammatory protein CD5L in plasma extracellular vesicles (EVs) and assess its as yet unknown relationship with lipid mediators in ACLF. With this aim, EVs were purified by size exclusion chromatography from the plasma of healthy subjects (HS) (n=6) and patients with compensated cirrhosis (CC) (n=6), AD (n=11) and ACLF (n=11), which were defined as positive for CD9, CD5L and CD63 and their size, number, morphology and lipid mediator content were characterized by NTA, EM, and LC-MS/MS, respectively. Additionally, plasma CD5L was quantified by ELISA in 10 HS, 20 CC and 149 AD patients (69 ACLF). Moreover, macrophage CD5L expression and the biosynthesis of specialized lipid mediators (SPMs) were characterized in vitro in primary cells. Our results indicate that circulating EVs were significantly suppressed in cirrhosis, regardless of severity, and showed considerable alterations in CD5L and lipid mediator content as the disease progressed. In AD, levels of EV CD5L correlated best with those of the SPM RvE1. Analysis of total plasma supported these data and showed that, in ACLF, low CD5L levels were associated with circulatory (p<0.001), brain (p<0.008) and respiratory (p<0.05) failure (Mann-Whitney test). Functional studies in macrophages indicated a positive feedback loop between CD5L and RvE1 biosynthesis. In summary, we have determined a significant alteration of circulating EV contents in ACLF, with a loss of anti-inflammatory and pro-resolving molecules involved in the control of acute inflammation in this condition

Role of the Scavenger Receptor CD36 in Accelerated Diabetic Atherosclerosis

Diabetes mellitus entails increased atherosclerotic burden and medial arterial calcification, but the precise mechanisms are not fully elucidated. We aimed to investigate the implication of CD36 in inflammation and calcification processes orchestrated by vascular smooth muscle cells (VSMCs) under hyperglycemic and atherogenic conditions. We examined the expression of CD36, pro-inflammatory cytokines, endoplasmic reticulum (ER) stress markers, and mineralization-regulating enzymes by RT-PCR in human VSMCs, cultured in a medium containing normal (5 mM) or high glucose (22 mM) for 72 h with or without oxidized low-density lipoprotein (oxLDL) (24 h). The uptake of 1,1'-dioctadecyl-3,3,3',3-tetramethylindocarbocyanine perchlorate-fluorescently (DiI) labeled oxLDL was quantified by flow cytometry and fluorimetry and calcification assays were performed in VSMC cultured in osteogenic medium and stained by alizarin red. We observed induction in the expression of CD36, cytokines, calcification markers, and ER stress markers under high glucose that was exacerbated by oxLDL. These results were confirmed in carotid plaques from subjects with diabetes versus non-diabetic subjects. Accordingly, the uptake of DiI-labeled oxLDL was increased after exposure to high glucose. The silencing of CD36 reduced the induction of CD36 and the expression of calcification enzymes and mineralization of VSMC. Our results indicate that CD36 signaling is partially involved in hyperglycemia and oxLDL-induced vascular calcification in diabetes

The nuclear receptor LXR limits bacterial infection of host macrophages through a mechanism that impacts cellular NAD metabolism

Macrophages exert potent effector functions against invading microorganisms but constitute, paradoxically, a preferential niche for many bacterial strains to replicate. Using a model of infection by Salmonella Typhimurium, we have identified a molecular mechanism regulated by the nuclear receptor LXR that limits infection of host macrophages through transcriptional activation of the multifunctional enzyme CD38. LXR agonists reduced the intracellular levels of NAD+ in a CD38-dependent manner, counteracting pathogen-induced changes in macrophage morphology and the distribution of the F-actin cytoskeleton and reducing the capability of nonopsonized Salmonella to infect macrophages. Remarkably, pharmacological treatment with an LXR agonist ameliorated clinical signs associated with Salmonella infection in vivo, and these effects were dependent on CD38 expression in bonemarrow- derived cells. Altogether, this work reveals an unappreciated role for CD38 in bacterial-host cell interaction that can be pharmacologically exploited by activation of the LXR pathway

Association of a single nucleotide polymorphism combination pattern of the Klotho gene with non-cardiovascular death in patients with chronic kidney disease

Chronic kidney disease (CKD) is associated with an elevated risk of all-cause mortality, with cardiovascular death being extensively investigated. However, non-cardiovascular mortality represents the biggest percentage, showing an evident increase in recent years. Klotho is a gene highly expressed in the kidney, with a clear influence on lifespan. Low levels of Klotho have been linked to CKD progression and adverse outcomes. Single nucleotide polymorphisms (SNPs) of the Klotho gene have been associated with several diseases, but studies investigating the association of Klotho SNPs with noncardiovascular death in CKD populations are lacking. The main aim of this study was to assess whether 11 Klotho SNPs were associated with non-cardiovascular death in a subpopulation of the National Observatory of Atherosclerosis in Nephrology (NEFRONA) study (n ¼ 2185 CKD patients). After 48 months of follow-up, 62 cardiovascular deaths and 108 non-cardiovascular deaths were recorded. We identified a high non-cardiovascular death risk combination of SNPs corresponding to individuals carrying the most frequent allele (G) at rs562020, the rare allele (C) at rs2283368 and homozygotes for the rare allele (G) at rs2320762 (rs562020 GG/AG þ rs2283368 CC/CT þ rs2320762 GG). Among the patients with the three SNPs genotyped (n ¼ 1016), 75 (7.4%) showed this combination. Furthermore, 95 (9.3%) patients showed a low-risk combination carrying all the opposite genotypes (rs562020 AA þ rs2283368 TT þ rs2320762 GT/TT). All the other combinations [n ¼ 846 (83.3%)] were considered as normal risk. Using competing risk regression analysis, we confirmed that the proposed combinations are independently associated with a higher fhazard ratio [HR] 3.28 [confidence interval (CI) 1.51-7.12]g and lower [HR 6 × 10- (95% CI 3.3 × 10--1.1 × 10-)] risk of suffering a non-cardiovascular death in the CKD population of the NEFRONA cohort compared with patients with the normal-risk combination. Determination of three SNPs of the Klotho gene could help in the prediction of non-cardiovascular death in CKD

CD5L is a pleiotropic player in liver fibrosis controlling damage, fibrosis and immune cell content

© 2019 The Authors.[Background]: Chronic hepatic inflammation leads to liver fibrosis, which may progress to cirrhosis, a condition with high morbidity. Our aim was to assess the as yet unknown role of innate immunity protein CD5L in liver fibrosis. [Methods]: CD5L was measured by ELISA in plasma samples from cirrhotic (n = 63) and hepatitis (n = 39) patients, and healthy controls (n = 7), by immunohistochemistry in cirrhotic tissue (n = 12), and by quantitative RT-PCR in mouse liver cell subsets isolated by cell sorting. Recombinant CD5L (rCD5L) was administered into a murine model of CCl4-induced fibrosis, and damage, fibrosis and hepatic immune cell infiltration, including the LyC6hi (pro-fibrotic)-LyC6low (pro-resolutive) monocyte ratio were determined. Moreover, rCD5L was added into primary human hepatic stellate cells to study transforming growth factor β (TGFβ) activation responses. [Findings]: Cirrhotic patients showed elevated plasma CD5L concentrations as compared to patients with hepatitis and healthy controls (Mann-Whitney test p < 0·0001). Moreover, plasma CD5L correlated with disease progression, FIB4 fibrosis score (r:0·25, p < 0·0001) and tissue expression (r = 0·649; p = 0·022). Accordingly, CCl4-induced damage increased CD5L levels in total liver, particularly in hepatocytes and macrophages. rCD5L administration attenuated CCl4-induced injury and fibrosis as determined by reduced serum transaminase and collagen content. Moreover, rCD5L inhibited immune cell infiltration and promoted a phenotypic shift in monocytes from LyC6hi to LyC6low. Interestingly, rCD5L also had a direct effect on primary human hepatic stellate cells promoting SMAD7 expression, thus repressing TGFβ signalling.This work was supported by grants from the Fundació la Marató de TV3 (MTV3 2013-3610), AGAUR (2016 PROD 00094, 2017-SGR-490) to MRS, CSIC (PIE-201720E092) and also from the Instituto de Salud Carlos III (ISCIII), and ERDFs from the EU, ‘Una manera de hacer Europa’, (PI10/01565, PI13/1906, PI16/0974, PI13/02340, PI09/00751 and PI17/00673 to MRS, CA, and PS-B, respectively and PI14/00703 to LK). MRS, PS-B, CA, and CB were supported by the Miguel Servet (CPII14/00021; CPII15/00041), Ramón y Cajal (RYC-2010-07249), and Juan de la Cierva (FJCI-2014-20,505) programs, respectively

The Circulating Fatty Acid Transporter Soluble CD36 Is Not Associated with Carotid Atherosclerosis in Subjects with Type 1 and Type 2 Diabetes Mellitus

This study aimed to determine the association of fatty acid transporter plasma solublecluster of differentiation 36 (sCD36) with subclinical carotid atherosclerosis (SCA). A cross-sectionalstudy was conducted in 1023 subjects, 225 with type 1 diabetes (T1D), 276 with type 2 diabetes (T2D)and 522 who were nondiabetic. Carotid atherosclerotic plaque (CAP) presence was determined usingB-mode carotid ultrasound imaging. sCD36 were analysed by ELISA, and CD36 surface receptor andmRNA expression were measured by flow cytometry and real-time PCR. Logistic regression modelswere used to evaluate sCD36 as a biomarker of SCA. Up to 376 (36.75%) participants had at least oneCAP, 76 T1D, 164 T2D and 136 without diabetes, while the remaining 647 (63.25%) did not have anyCAP. There were no differences in sCD36 between patients with and without CAP in T1D (p=0.287)or T2D (p=0.513). Although nondiabetic subjects with plaques had lower sCD36 levels than thosewithout (p=0.023), the multivariate models revealed no association of sCD36 with CAP in any of thethree study groups. No differences were found in surface CD36 or CD36 mRNA expression between the patients with and without CAP. sCD36 is not associated with SCA in type 1 or type 2 diabetic orin nondiabetic subjects.This research was supported by grants from the European Foundation for the study of diabetes (2014-EFSD-00914) and European Regional Development Fund (ERDF). CIBER for Diabetes and Associated Metabolic Diseases (CIBERDEM), CIBER on Liver and Digestive Diseases (CIBEREHD), and CIBER on Physiopathology ofObesity and Nutrition (CIBEROBN) are initiatives of the Carlos III National Institute of Health, Spain

Crystal structure of the third extracellular domain of CD5 reveals the fold of a group B scavenger cysteine-rich receptor domain

Scavenger receptor cysteine-rich ( SRCR) domains are ancient protein modules widely found among cell surface and secreted proteins of the innate and adaptive immune system, where they mediate ligand binding. We have solved the crystal structure at 2.2 angstrom of resolution of the SRCR CD5 domain III, a human lymphocyte receptor involved in the modulation of antigen specific receptor-mediated T cell activation and differentiation signals. The first structure of a member of a group B SRCR domain reveals the fold of this ancient protein module into a central core formed by two antiparallel beta-sheets and one alpha-helix, illustrating the conserved core at the protein level of genes coding for group A and B members of the SRCR superfamily. The novel SRCR group B structure permits the interpretation of site-directed mutagenesis data on the binding of activated leukocyte cell adhesion molecule ( ALCAM/CD166) binding to CD6, a closely related lymphocyte receptor homologue to CD5.Peer reviewe

The Nuclear Receptor LXR Limits Bacterial Infection of Host Macrophages through a Mechanism that Impacts Cellular NAD Metabolism

Altres ajuts: Fundació La Marató de TV3 (080930, 20134030); COST Action BM1404; ANII (INNOVA II,FCE_1_2014_1_104002, Uruguay)Macrophages exert potent effector functions against invading microorganisms but constitute, paradoxically, a preferential niche for many bacterial strains to replicate. Using a model of infection by Salmonella Typhimurium, we have identified a molecular mechanism regulated by the nuclear receptor LXR that limits infection of host macrophages through transcriptional activation of the multifunctional enzyme CD38. LXR agonists reduced the intracellular levels of NAD+ in a CD38-dependent manner, counteracting pathogen-induced changes in macrophage morphology and the distribution of the F-actin cytoskeleton and reducing the capability of nonopsonized Salmonella to infect macrophages.remarkably, pharmacological treatment with an LXR agonist ameliorated clinical signs associated with Salmonella infection in vivo, and these effects were dependent on CD38 expression in bonemarrow- derived cells. Altogether, this work reveals an unappreciated role for CD38 in bacterial-host cell interaction that can be pharmacologically exploited by activation of the LXR pathway