CHK1 activates mitophagy to attenuate cardiac aging via inhibiting AHSA1-ubiquitination

With the acceleration of global population aging, the progressive deterioration of cardiac structure and function has become a critical determinant of cardiovascular health, presenting a significant public health challenge. Checkpoint kinase 1 (CHK1), a key cell cycle checkpoint protein, plays an essential role in various biological processes by mediating signaling cascades. While CHK1 has been shown to be important for heart regeneration, its role in the aging process of the heart remains unclear. In this study, we investigated the alterations in CHK1 expression in aging hearts and elucidated the underlying regulatory mechanisms. In both in vivo and in vitro models, CHK1 expression was significantly downregulated during aging. To assess its functional role, we generated cardiomyocyte-specific CHK1 overexpression and knockout mice and compared their cardiac performance. We found that CHK1 overexpression alleviated age-associated cardiac dysfunction, while CHK1 knockout worsened cardiac function in aged mice. Furthermore, CHK1 overexpression significantly attenuated doxorubicin (DOX)-induced acutely senescence in adult mouse cardiomyocytes (AMCMs) and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Mechanistic studies revealed that CHK1 overexpression delayed cardiac aging by activating heat shock protein 90 (HSP90)-mediated mitophagy. Immunoprecipitation and mass spectrometry (IP-MS) analyses demonstrated that CHK1 directly interacts with the activator of HSP90 ATPase homolog 1 (AHSA1), thereby suppressing TRIM8-mediated ubiquitination and degradation, facilitating AHSA1-HSP90 complex formation, and enhancing HSP90 ATPase activity. Overall, our results suggest that CHK1 overexpression activates mitophagy via the AHSA1-HSP90 pathway to mitigate cardiac aging. This study highlights the critical role of CHK1 in cardiac aging and proposes a potential therapeutic strategy for aging-associated cardiomyopathy and heart failure.