Project description:This experiment aimed at characterising the signalling pathways downstream SUCNR1 activation in murine Neural Stem Cells (NSCs). To this end, we profiled by microarray the gene expression changes induced by succinate stimulation in both wild type NSCs and GPR91-deficient NSCs.
Project description:Macrophages, a key cellular component of inflammation, become functionally polarized in a signal- and context-specific manner. Th2 cytokines such as IL-4 polarize macrophages to a state of alternative activation that limits inflammation and promotes wound healing. Alternative activation is mediated by a transcriptional program that is influenced by epigenomic modifications including histone acetylation. To determine if Histone Deacetylase 3 (HDAC3) has a role in macrophage polarization including alternative activation, we have performed global gene expression analysis in macrophages with and without HDAC3 and with or without IL-4 exposure. From this data, we conclude that macrophages lacking histone deacetylase 3 (HDAC3) display a polarization phenotype similar to IL-4 induced alternative activation and furthermore are hyper-responsive to IL-4 stimulation. Mouse bone marrow derived macrophages were obtained from both control and HDAC3 KO animals and treated with vehicle control (BSA) or IL-4 for 24 hours. RNA was isolated and subjected to analysis using an Agilent Whole Genome Microarray Kit.
Project description:Succinate functions both as a classical TCA cycle metabolite and as an extracellular metabolic stress signal sensed by the mainly Gi-coupled succinate receptor, SUCNR1. In the present study, we characterize and compare effects and signaling pathways activated by succinate and both classes of non-metabolite SUCNR1 agonists. By use of specific receptor and pathway inhibitors, rescue in G protein depleted cells and monitoring of receptor G protein activation by BRET we surprisingly identify Gq rather than Gi signaling, to be responsible for SUCNR1-mediated effects on basic transcriptional regulation. Importantly, in primary human M2 macrophages, where SUCNR1 is highly expressed, we demonstrate that physiological concentrations of extracellular succinate act through SUCNR1 activated Gq signaling to efficiently regulate transcription of immune function genes in a manner that hyperpolarizes their M2 versus M1 phenotype. Thus, sensing of stress-induced extracellular succinate by SUCNR1 is an important transcriptional regulator in human M2 macrophages through Gq signaling.
Project description:Obesity induces macrophages to drive inflammation in adipose tissue, a crucial step towards the development of type 2 diabetes. The tricarboxylic acid (TCA) cycle intermediate succinate is released from cells under metabolic stress and has recently emerged as a metabolic signal induced by proinflammatory stimuli. We therefore investigated whether succinate receptor 1 (SUCNR1) could play a role in the development of adipose tissue inflammation and type 2 diabetes. Succinate levels were determined in human plasma samples from individuals with type 2 diabetes and non-diabetic participants. Succinate release from adipose tissue explants was studied. Sucnr1 -/- and wild-type (WT) littermate mice were fed a high-fat diet (HFD) or low-fat diet (LFD) for 16 weeks. Serum metabolic variables, adipose tissue inflammation, macrophage migration and glucose tolerance were determined. We show that hypoxia and hyperglycaemia independently drive the release of succinate from mouse adipose tissue (17-fold and up to 18-fold, respectively) and that plasma levels of succinate were higher in participants with type 2 diabetes compared with non-diabetic individuals (+53%; p < 0.01). Sucnr1 -/- mice had significantly reduced numbers of macrophages (0.56 ± 0.07 vs 0.92 ± 0.15 F4/80 cells/adipocytes, p < 0.05) and crown-like structures (0.06 ± 0.02 vs 0.14 ± 0.02, CLS/adipocytes p < 0.01) in adipose tissue and significantly improved glucose tolerance (p < 0.001) compared with WT mice fed an HFD, despite similarly increased body weights. Consistently, macrophages from Sucnr1 -/- mice showed reduced chemotaxis towards medium collected from apoptotic and hypoxic adipocytes (-59%; p < 0.05). Our results reveal that activation of SUCNR1 in macrophages is important for both infiltration and inflammation of adipose tissue in obesity, and suggest that SUCNR1 is a promising therapeutic target in obesity-induced type 2 diabetes.
Project description:This SuperSeries is composed of the following subset Series: GSE33596: Histone Deacetylase 3 is an Epigenomic Brake in Macrophage Alternative Activation (ChIP-Seq) GSE33608: Histone Deacetylase 3 is an Epigenomic Brake in Macrophage Alternative Activation (microarray) Refer to individual Series
Project description:In response to microenvironmental signals macrophages undergo different activation, indicated as classic/M1 and alternative/M2 polarization. C-Myc transcription factor could be an essential player in M2 polarization. Functional relevance of c-Myc in M2 macrophage biology is investigated by evaluating the effect of 100-58F4, on the transcriptional profile induced on human macrophages by IL-4. Human monocytes were obtained from normal donor buffy coats by two-step gradient centrifugation using Ficoll (Biochrom) and Percoll (Amersham). Non-adherent cells were discarded, and the purified monocytes were incubated for 7 days in RPMI 1640 (Biochom) supplemented with 10% FCS (HyClone) and 100 ng/mL M-CSF to obtain resting macrophages. Macrophage polarization was obtained by removing the culture medium and culturing cells in RPMI 1640 supplemented with 10% FCS and 100 ng/mL LPS plus 20 ng/mL IFN-gamma (M1 polarization) or 20 ng/mL IL-4 (M2 polarization) for 24 h. When needed, chemical inhibitors were added with IL-4.
Project description:Macrophages, a key cellular component of inflammation, become functionally polarized in a signal- and context-specific manner. Th2 cytokines such as IL-4 polarize macrophages to a state of alternative activation that limits inflammation and promotes wound healing. Alternative activation is mediated by a transcriptional program that is influenced by epigenomic modifications including histone acetylation. To determine if Histone Deacetylase 3 (HDAC3) has a role in macrophage polarization including alternative activation, we have performed global gene expression analysis in macrophages with and without HDAC3 and with or without IL-4 exposure. From this data, we conclude that macrophages lacking histone deacetylase 3 (HDAC3) display a polarization phenotype similar to IL-4 induced alternative activation and furthermore are hyper-responsive to IL-4 stimulation.
Project description:In response to microenvironmental signals macrophages undergo different activation, indicated as classic/M1 and alternative/M2 polarization. C-Myc transcription factor could be an essential player in M2 polarization. Functional relevance of c-Myc in M2 macrophage biology is investigated by evaluating the effect of 100-58F4, on the transcriptional profile induced on human macrophages by IL-4.