YY1/INSIG1 enhances atherosclerosis progression by regulating AMPK-mTOR signaling

The regulatory mechanisms of Insulin-Induced Gene 1 (INSIG1) in atherosclerosis (AS) remain largely unknown. This study aimed to investigate the role of the YY1/INSIG1 axis and its regulation of the AMPK-mTOR signaling pathway in AS pathogenesis.

Atherosclerosis mouse models were established. RNA sequencing was performed to determine differentially expressed genes. Human umbilical vein endothelial cells (HUVECs) and human vascular smooth muscle cells (HVSMCs) were treated with ox-LDL and/or transfected with plasmids for INSIG1. Cellular functions were evaluated by proliferation, migration, and inflammation assays. Key proteins in the AMPK/mTOR pathway were measured by western blotting. The regulation of INSIG1 by transcription factor YY1 was confirmed using a dual-luciferase reporter assay. Crucially, the functional role of the INSIG1-AMPK axis was validated in vivo using an AMPK inhibitor (Dorsomorphin, DM) in the AS mouse model.

INSIG1 expression was significantly downregulated in atherosclerosis mouse models and patients. In HUVECs, INSIG1 promoted cell proliferation, migration, and invasion, while in HVSMCs, INSIG1 suppressed these functions. Higher INSIG1 levels reduced the proinflammatory mediators IL-6 and MCP-1. INSIG1 overexpression activated AMPK and inhibited mTOR phosphorylation. Crucially, in the mouse model, the protective anti-atherosclerotic effects of INSIG1 overexpression were significantly abolished by the administration of the AMPK inhibitor DM. Bioinformatics suggested a potential interaction between YY1 and INSIG1 in atherosclerosis, which was confirmed by a dual-luciferase reporter assay that demonstrated YY1 directly regulate the mRNA transcription of INSIG1.

These findings underscore the relevance of INSIG1 and YY1 in atherosclerosis and maybe in its treatment.