Icariin-mediated structural stabilization of TNF-α triggers a pro-regenerative signaling switch for endothelial recovery after myocardial infarction.

BACKGROUND

Coronary microvascular recovery is essential for cardiac repair post-myocardial infarction (MI), but the endogenous signals driving endothelial cell (EC) cycle reentry remain elusive. While tumor necrosis factor-alpha (TNF-α) is typically considered a pro-inflammatory mediator, its biological effects are profoundly influenced by protein conformation. In this study, we identify a novel pro-regenerative signaling switch where structural stabilization of TNF-α, rather than its inhibition, dictates endothelial neogenesis.

METHODS

A rat model of HF was established via left anterior descending coronary artery ligation. In vitro, coronary microvascular endothelial cells (CMECs) were subjected to oxygen-glucose deprivation and reoxygenation. Bioinformatics analysis, molecular docking (MD) and molecular dynamics simulations (MDs) were employed to identify potential targets. The effects of Icariin (ICA) on EC proliferation, migration, and the TNF signaling pathway were validated using EdU assays, wound healing assays, and Western blotting.

RESULTS

Bioinformatics analysis and experimental validation identified the TNF signaling pathway as a critical regulator of EC regeneration. ICA significantly improved cardiac function and promoted CD31+/BrdU+ endothelial cell proliferation in the peri-infarction area of HF rats. MD and MDs revealed that ICA directly binds to the hydrophobic pocket of TNF-α, enhancing its structural stability. Mechanistically, ICA treatment upregulated the expression of cell cycle-promoting proteins by stabilizing TNF signaling, whereas TNF inhibition significantly abrogated the pro-proliferative effects of ICA. Our findings suggest that ICA may promote endothelial regeneration and alleviate HF in part by structurally stabilizing TNF-α and activating the downstream cell cycle cascade.

CONCLUSION

This study provides a mechanistic basis for the ethnopharmacological use of the traditional herb Epimedium by demonstrating that its primary bioactive monomer, ICA, acts as a potential candidate for revascularization therapy.