HMGA2 inhibits Pink1-mediated mitophagy and promotes vascular calcification

Mitochondrial dysfunction is implicated in the development of vascular calcification, whereas protective mitophagy helps to hinder its progression. HMGA2 plays a pivotal role in regulating mitochondrial integrity and mitophagy. However, the precise impact of HMGA2-controlled mitophagy on vascular calcification remains unclear. In our study, we observed elevated HMGA2 expression during both Vitamin D3-induced aortic calcification in mice and β-GP-induced calcification of mouse aortic vascular smooth muscle (MOVAS). Additionally, we identified dynamic changes in mitophagy in MOVAS and demonstrated that HMGA2 knockdown promoted mitophagy, exerting a protective effect against vascular calcification in both in vivo and in vitro settings. Preconditioning with the autophagy inhibitor chloroquine diminished the protective effect of HMGA2 knockdown on aortic calcification in mice by inhibiting mitophagy. Furthermore, we observed an increase in cytoplasmic HMGA2 levels in MOVAS following vascular calcification, along with its binding to PTEN induced kinase 1 (Pink1) in the cytoplasm. This affects the distribution of Pink1, which cannot be transferred to the mitochondrial outer membrane to initiate mitophagy. Subsequently, silencing Pink1 exacerbated mitochondrial damage and apoptosis by inhibiting mitophagy, thereby promoting vascular calcification in β-GP-treated MOVAS. Our results indicated that cytosolic HMGA2 bound to Pink1, inhibiting mitophagy by impeding Pink1's relocation from the cytosol to the mitochondria, thereby reducing mitophagy activation, inducing apoptosis, ultimately accelerating the transition of MOVAS to an osteoblastic phenotype and calcium deposition. In conclusion, inducing mitophagy pharmacologically by targeting HMGA2 may represent a promising therapeutic approach for managing vascular calcification.