Opposing functions of miR-155-5p and Socs1 drive vascular inflammation in diabetes-accelerated atherosclerosis.

BACKGROUND: Diabetes accelerates atherosclerosis by driving persistent vascular inflammation. MicroRNA-155 (miR-155) is a post-transcriptional regulator of inflammatory genes, while suppressor of cytokine signaling 1 (Socs1) limits Janus kinase (JAK)/signal transducer and activator of transcription (STAT)-mediated cytokine responses. We explored how the imbalance between miR-155-5p and Socs1 contributes to atherosclerotic plaque progression in diabetes. METHODS: Apolipoprotein E knockout (ApoE-/-) mice were studied in two settings: age-dependent atherosclerosis progression under non-diabetic conditions, and streptozotocin-induced diabetes to model accelerated atherosclerosis. Diabetic mice received a miR-155-5p inhibitor, a Socs1-expressing adenovirus, or respective controls. Lesion size, composition, and gene expression were analyzed. Cultured vascular smooth muscle cells (VSMCs) and macrophages were transfected with miR-155-5p mimic/inhibitor and Socs1 siRNA/plasmid to assess inflammatory responses, phenotypes, and efferocytosis under diabetic-like conditions. RESULTS: During atherosclerosis progression, vascular miR-155-5p inversely correlated with Socs1 and positively with lesion size, while Socs1 correlated negatively with plaque burden. In diabetic mice, miR-155-5p inhibition reduced lesion area, lipid/collagen and macrophage/VSMC ratios, pro-inflammatory cytokines, M1 macrophages and synthetic VSMC markers, while increasing Socs1, M2 and contractile VSMC genes. Socs1 gene transfer reproduced these effects by reducing miR-155-5p and Stat1 expression, and lesion size. In vitro, miR-155-5p mimic suppressed Socs1, activated STAT1 and inflammatory phenotypes in macrophages and VSMCs, whereas miR-155-5p inhibition had opposite effects. Socs1 silencing amplified inflammation, and its overexpression counteracted miR-155-5p actions. Moreover, miR-155-5p inhibition reduced soluble Mer receptor tyrosine kinase (MerTK) in plaques and macrophages, indicating improved efferocytosis, whereas the mimic promoted macrophage MerTK shedding and impaired apoptotic cell clearance. CONCLUSION: Reciprocal regulation between miR-155-5p and Socs1 influences vascular inflammation, phenotypic changes, and defective efferocytosis in a diabetic context. Targeting this axis may restore resolution mechanisms and enhance plaque stability in diabetes-associated vascular disease. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12933-026-03121-3.