Abstract 14672: Regulation of Succinate Signaling and Immunometabolism in Diabetes-Associated Atherosclerosis by Microrna-369-3p

Abstract

Introduction: The risk of atherosclerotic cardiovascular disease (ASCVD) is increased in people with diabetes. Diabetes (D) is associated with impaired metabolism and functionality of macrophages (Mps), resulting in chronic inflammation. Identifying factors to combat metabolic alterations and promote resolution of inflammation remains an unmet goal. microRNAs (miRs) orchestrate multiple signaling events in Mps and regulate inflammation. Hypothesis: miR-369-3p regulates metabolic reprogramming in Mps during diabetes-associated atherosclerosis (D-AS). Methods and Results: miRNA-seq profiling from aortic intimal lesions of LDLR-/- mice on a high-fat sucrose containing (HFSC) diet revealed miR-369-3p downregulation with D-AS progression. miR-369-3p was also downregulated in PBMCs derived from D and D-associated ASCVD patients. Cell-type profiling showed miR-369-3p enrichment in mouse bone marrow derived Mps (BMDMs). oxLDL-stimulated BMDMs (foam cells, FCs) resulted in marked downregulation of miR-369-3p, increased secretion of IL1-β, and metabolic shift of oxidative phosphorylation (OXPHOS) to glycolysis, while miR-369-3p overexpression (miR-369-3p O/E) favored OXPHOS over glycolysis and reduced IL1-β secretion. Metabolomics revealed succinate, a key immunometabolite was profoundly elevated extracellularly from FCs, while miR-369-3p O/E reversed this phenotype. Extracellular succinate activates its receptor, GPR91. Indeed, GPR91 was upregulated in FCs while miR-369-3p O/E significantly repressed GPR91. 3’UTR luciferase reporter assay confirmed GPR91 as a miR-369-3p target. miR-369-3p O/E dampened GPR91-mediated inflammasome activation and mitochondrial dysfunction in FCs by decreasing p-ERK, p-DRP1, and NLRP3. Therapeutic delivery of miR-369-3p in LDLR-/- mice fed HFSC diet for 12 weeks reduced plaque size by ORO staining and plasma IL1-β. Flow cytometry of aortic Mps revealed that miR-369-3p decreased GPR91 expression by ~50%, along with a decrease in M1 and increase in M2-like-Mps. Conclusions: miR-369-3p confers a pro-resolving role in regulating lipid-driven inflammation and metabolic rewiring in Mps via targeting GPR91 and preventing D-AS plaque progression.