Abstract Body: Introduction: Although atherosclerotic plaque progression is well studied, mechanisms governing diabetes-impaired atherosclerosis regression remain poorly understood. We identified an immunometabolic axis involving microRNA-369-3p (miR-369-3p) and the succinate receptor GPR91 that promotes vascular inflammation when miR-369-3p is suppressed in diabetes.
Hypothesis: Dysregulation of the miR-369-3p/GPR91-succinate axis limits macrophage pro-resolving functions during diabetes-associated atherosclerosis regression. We aim to investigate how miR-369-3p restoration drives macrophage-mediated plaque stability in diabetic atherosclerosis.
Methods: Ldlr-/- mice were fed a high fat sucrose-containing (HFSC) diet for 12 weeks and switched to chow for 6 weeks to induce regression, receiving either non-specific control (NS-m) or miR-369-3p mimics (369-m) intravenously. Bone marrow chimeras were generated using Ldlr-/- (CD45.1) recipients reconstituted with wild-type or GPR91-/- (CD45.2) bone marrow. Plaque remodeling and immune composition were assessed by histology and lesional flow cytometry. Hematopoietic recruitment was traced using CD45 congenic markers. Pro-resolving gene expression was analyzed by RNA-seq in FACS-sorted lesional macrophages, and efferocytosis was assessed in BMDMs.
Results: miR-369-3p mimic therapy reduced lesion size and macrophage content, lowered circulating cytokines (IL-1β, IL-6, and TNF-α) and immunometabolite succinate, and induced a lesional macrophage shift from M1 to M2 states. These effects were independent of effects on circulating lipid profile. Plaques exhibited increased fibrous cap thickness and accumulation of Foxp3+ regulatory T cells (Tregs). Hematopoietic loss of GPR91 similarly accelerated regression, reducing lesion size and necrosis while increasing M2 macrophages and Ly6C^lo monocyte recruitment. Lesional macrophages from miR-369-3p treated mice showed increased expression of pro-resolving and efferocytosis-associated genes (Il10, Trem2), and miR-369-3p–treated or GPR91-/- BMDMs demonstrated enhanced efferocytosis.
Conclusion: These findings identify the miR-369-3p/GPR91 axis as a critical immunometabolic regulator of lesional macrophage efferocytosis, immune resolution, and plaque stabilization during diabetes-associated atherosclerosis regression. Targeting this pathway restores a pro-resolving plaque microenvironment and represents a promising therapeutic strategy to overcome impaired regression in diabetes.