Overexpression of hnRNPK and inhibition of cytoplasmic translocation ameliorate lipid disorder in doxorubicin-induced cardiomyopathy via PINK1/Parkin-mediated mitophagy

Lipid metabolism has been identified as a potential target for the treatment of doxorubicin-induced cardiomyopathy (DIC). Mitochondria, as a central regulator of energy production and utilization, plays a crucial role in this process, and enhancing mitophagy holds promise in mitigating myocardial damage in DIC. However, the relationship between mitophagy and lipid metabolism remains unclear, and the key molecules mediating this connection remain to be elucidated. Among these candidates, heterogeneous nuclear ribonucleoprotein K (hnRNPK) emerges as a potential regulator of mitophagy and metabolism. However, its specific role in DIC remains unclear. In this study, we established chronic DIC models both in vivo and in vitro to assess the relationship between hnRNPK levels, mitophagy, and lipid metabolism, as well as to evaluate the impact of hnRNPK on cardiac function. Our findings revealed that hnRNPK expression is significantly reduced in the hearts of doxorubicin (DOX)-treated mice. Notably, hnRNPK overexpression improves cardiac function and effectively reduces lipid accumulation by enhancing mitophagy. Mechanistically, hnRNPK expression was found to be downregulated in DIC, accompanied by its translocation from the nucleus to the cytoplasm, thereby reducing the transcriptional regulation of PINK1. Overexpression of hnRNPK and inhibition of its cytoplasmic translocation alleviates DOX-induced lipid accumulation by regulating the PINK1/Parkin pathway. These findings underscore a previously unrecognized role of hnRNPK in inhibiting lipid accumulation to prevent DIC.