Ripk1-dependent PANoptosis promotes EndMT and aggravates hypoglycemia-related cardiac fibrosis in diabetes

Hypoglycemia impairs cardiac function in patients with diabetes, yet its underlying mechanisms remain elusive. Exploring the mechanism of hypoglycemia-related cardiovascular endothelial damage in diabetes from a single-cell perspective and identifying specific intervention measures will assist with preventing adverse cardiovascular events in patients with diabetes. This retrospective study includes participants who experienced ≥one hypoglycemia episode from Grade 3A hospitals to elucidate its effect on cardiac function in DM. Single-nucleus (sn) RNA-Seq has been used to determine lineage-specific gene expression, subpopulation composition, and intercellular communication. The findings were further validated through in vivo and in vitro biological assays. Hypoglycemia significantly reduced left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) in both diabetic patients and db/db mice. snRNA-seq of cardiac tissue under hypoglycemic conditions showed significant enrichment of key genes linked to cell death, inflammation, and fibrosis within endothelial cells, macrophages, fibroblasts, and cardiomyocytes, with endothelial cells demonstrating a particularly critical regulatory role. Hypoglycemia triggered Ripk1-dependent PANoptosis in endothelial cells, which was accompanied by EndMT and cardiac fibrosis. Ripk1 knockdown inhibits the activation of the COLLAGEN signaling pathway and attenuates PANoptosis, EndMT, and fibrosis in low glucose-treated Mouse Cardiac Microvascular Endothelial Cells (MCMECs). Correspondingly, endothelial cell-specific Ripk1 conditional knockout improved cardiac function in a diabetichypoglycemia mouse model and effectively mitigated cardiac PANoptosis, EndMT, and COLLAGEN pathway activation. Hypoglycemia activates the COLLAGEN signaling pathway through Ripk1-dependent PANoptosis, thereby triggering EndMT and exacerbating cardiac fibrosis. Inhibition of Ripk1 effectively alleviates hypoglycemia-associated cardiac dysfunction.