ABSTRACT
Dysregulated B cell cytokine production contributes to pathogenesis of immune-mediated diseases including multiple sclerosis (MS); however, the underlying mechanisms are poorly understood. In this study we investigated how cytokine secretion by pro-inflammatory (GM-CSF-expressing) and anti-inflammatory (IL-10-expressing) B cells is regulated. Pro-inflammatory human B cells required increased oxidative phosphorylation (OXPHOS) compared with anti-inflammatory B cells. OXPHOS reciprocally modulated pro- and anti-inflammatory B cell cytokines through regulation of adenosine triphosphate (ATP) signaling. Partial inhibition of OXPHOS or ATP-signaling including with BTK inhibition resulted in an anti-inflammatory B cell cytokine shift, reversed the B cell cytokine imbalance in patients with MS, and ameliorated neuroinflammation in a myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalitis mouse model. Our study identifies how pro- and anti-inflammatory cytokines are metabolically regulated in B cells and identifies ATP and its metabolites as a "fourth signal" that shapes B cell responses and is a potential target for restoring the B cell cytokine balance in autoimmune diseases.
Subject(s)
B-Lymphocytes , Cytokines , Encephalomyelitis, Autoimmune, Experimental , Inflammation , Multiple Sclerosis , Oxidative Phosphorylation , Animals , Multiple Sclerosis/immunology , Humans , Cytokines/immunology , Cytokines/metabolism , Mice , B-Lymphocytes/immunology , Encephalomyelitis, Autoimmune, Experimental/immunology , Inflammation/immunology , Female , Male , Mice, Inbred C57BL , Adult , Adenosine Triphosphate/metabolism , Middle AgedABSTRACT
BACKGROUND: Restoring the capacity of endothelial progenitor cells (EPCs) to promote angiogenesis is the major therapeutic strategy of diabetic peripheral artery disease. The aim of this study was to investigate the effects of GLP-1 (glucagon-like peptide 1; 32-36)-an end product of GLP-1-on angiogenesis of EPCs and T1DM (type 1 diabetes) mice, as well as its interaction with the classical GLP-1R (GLP-1 receptor) pathway and its effect on mitochondrial metabolism. METHODS: In in vivo experiments, we conducted streptozocin-induced type 1 diabetic mice as a murine model of unilateral hind limb ischemia to examine the therapeutic potential of GLP-1(32-36) on angiogenesis. We also generated Glp1r-/- mice to detect whether GLP-1R is required for angiogenic function of GLP-1(32-36). In in vitro experiments, EPCs isolated from the mouse bone marrow and human umbilical cord blood samples were used to detect GLP-1(32-36)-mediated angiogenic capability under high glucose treatment. RESULTS: We demonstrated that GLP-1(32-36) did not affect insulin secretion but could significantly rescue angiogenic function and blood perfusion in ischemic limb of streptozocin-induced T1DM mice, a function similar to its parental GLP-1. We also found that GLP-1(32-36) promotes angiogenesis in EPCs exposed to high glucose. Specifically, GLP-1(32-36) has a causal role in improving fragile mitochondrial function and metabolism via the GLP-1R-mediated pathway. We further demonstrated that GLP-1(32-36) rescued diabetic ischemic lower limbs by activating the GLP-1R-dependent eNOS (endothelial NO synthase)/cGMP/PKG (protein kinase G) pathway. CONCLUSIONS: Our study provides a novel mechanism with which GLP-1(32-36) acts in modulating metabolic reprogramming toward glycolytic flux in partnership with GLP-1R for improved angiogenesis in high glucose-exposed EPCs and T1DM murine models. We propose that GLP-1(32-36) could be used as a monotherapy or add-on therapy with existing treatments for peripheral artery disease. REGISTRATION: URL: www.ebi.ac.uk/metabolights/; Unique identifier: MTBLS9543.
Subject(s)
Diabetes Mellitus, Experimental , Endothelial Progenitor Cells , Glucagon-Like Peptide 1 , Glucagon-Like Peptide-1 Receptor , Glycolysis , Hindlimb , Ischemia , Mice, Inbred C57BL , Mice, Knockout , Neovascularization, Physiologic , Signal Transduction , Animals , Ischemia/drug therapy , Ischemia/physiopathology , Ischemia/metabolism , Glucagon-Like Peptide-1 Receptor/metabolism , Glucagon-Like Peptide-1 Receptor/agonists , Neovascularization, Physiologic/drug effects , Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Experimental/metabolism , Glycolysis/drug effects , Glucagon-Like Peptide 1/analogs & derivatives , Glucagon-Like Peptide 1/pharmacology , Humans , Hindlimb/blood supply , Male , Endothelial Progenitor Cells/metabolism , Endothelial Progenitor Cells/drug effects , Diabetic Angiopathies/metabolism , Diabetic Angiopathies/physiopathology , Diabetic Angiopathies/drug therapy , Diabetic Angiopathies/etiology , Nitric Oxide Synthase Type III/metabolism , Diabetes Mellitus, Type 1/drug therapy , Diabetes Mellitus, Type 1/metabolism , Cells, Cultured , Angiogenesis Inducing Agents/pharmacology , Peptide Fragments/pharmacology , Mice , Muscle, Skeletal/blood supply , Muscle, Skeletal/drug effects , Muscle, Skeletal/metabolism , Disease Models, Animal , Incretins/pharmacology , AngiogenesisABSTRACT
Acupuncture at ST36 can alleviate a variety of autoimmune diseases, including experimental autoimmune encephalomyelitis (EAE), while the specific mechanism for the treatment of EAE is not clear. In this study, we found that acupuncture at ST36 can significantly increase the excitability of splenic sympathetic nerve, and promote the differentiation of peripheral B and CD4+T cells in the anti-inflammatory direction. After blocking the splenic sympathetic nerve with 6-OHDA, this anti-inflammatory effect of acupuncture is partially reversed. In addition, the results of western blot and qPCR showed that acupuncture at ST36 simultaneously activated the ß2-AR-cAMP signaling pathway in the splenic B and CD4+T cells, and this activation was more significant in B cells. In vitro, when CD4+T cells were cultured alone, norepinephrine (NE) had no significant effect on their differentiation. While in the presence of B cells, NE significantly promotes the anti-inflammatory differentiation of B and CD4+T cells. Therefore, the above results reveal that acupuncture can relieve EAE by stimulating the sympathetic nerves of spleen, mainly through acting on B cells to mediate anti-inflammatory effects, and indirectly affecting the function of CD4+T cells.
