4-HNE induces cell death through the VCP-related ubiquitination pathway in diabetic cardiomyopathy and the protective effect of metformin.

Abstract

BACKGROUND: Metformin is an approved anti diabetes drug and has potential cardioprotective effects. It is unclear whether the antioxidant effect plays a role in this process. The reactive carbonyl compound 4-HNE, produced during lipid peroxidation, is highly reactive and has been implicated in the pathology of heart diseases, such as diabetic cardiomyopathy, although the exact mechanisms remain unclear. In this study, we identified 4-HNE protein adducts by mass spectrometry in cardiomyocytes, and investigated the mechanism of 4-HNE induced cell death and the protective effect of metformin in cardiomyocytes and diabetic cardiomyopathy models. METHODS: H9C2 cardiomyocytes were cultured and treated with different concentrations of 4-HNE for in vitro experiments. A mouse model of diabetic cardiomyopathy was established by HFD feeding and STZ injection, and treated with metformin. RESULTS: 4-HNE covalently binds to the key protein VCP to mediate cardiomyocyte death. 4-HNE inhibits the ATPase activity of VCP and disrupted its downstream signaling pathway, including increased ubiquitinated protein levels, unfolded protein response, and ultimately leads to cardiomyocyte death. In contrast, overexpression of VCP in H9C2 cardiomyocytes protected 4-HNE induced protein ubiquitination and cell death. Mass spectrometry analysis revealed that 4-HNE binds to VCP at residues K336. In addition, metformin reduced the ubiquitination and death of cardiomyocytes induced by 4-HNE through activation of Nrf2-GSTP1 pathway. In HFD-STZ diabetic cardiomyopathy mice, metformin treatment significantly improved cardiac function, reduced cardiac fibrosis and apoptosis, accompanied by a decrease in the levels of 4-HNE adducts and protein ubiquitination. CONCLUSION: Our results show that 4-HNE directly binds to VCP and disrupts its signaling pathway, induces ubiquitination accumulation, which ultimately leads to cardiomyocyte death, providing a new mechanism for the cardiac injury of 4-HNE. Meanwhile, metformin effectively alleviates 4-HNE induced ubiquitination and cell death in cardiomyocytes and diabetic cardiomyopathy models, and improves cardiac function, demonstrating potential therapeutic effects.

Key Findings

• 4-HNE covalently binds to VCP at residue K336, inhibiting its ATPase activity and disrupting downstream signaling.
• Disruption of VCP function by 4-HNE leads to increased protein ubiquitination, unfolded protein response, and cardiomyocyte death.
• Metformin activates the Nrf2-GSTP1 pathway, reducing 4-HNE-induced ubiquitination and cardiomyocyte death, improving cardiac function in diabetic cardiomyopathy models.

Clinical Significance

Citation

Liang Renshan, Lin Peibin, Yin Dazhonget al.. 4-HNE induces cell death through the VCP-related ubiquitination pathway in diabetic cardiomyopathy and the protective effect of metformin. Free radical research. 2026-Apr-25.