Targeting TOM70 crotonylation to improve hypoxic vascular dysfunction: A new strategy for treating myocardial...

The current treatment strategies for myocardial infarction (MI) mainly focus on recanalization of infarct-related arteries to alleviate myocardial damage. In contrast, the role of promoting microangiogenesis has not received sufficient attention. Lysine crotonylation (Kcr), a novel posttranslational protein modification, has an unclear role in revascularization following MI.

This study investigated the role of TOM70 crotonylation in angiogenesis following MI and elucidated its potential mechanisms.

We first established a mouse model of MI and an in vitro model of hypoxia in hypoxic human umbilical vein endothelial cells (HUVECs). Using crotonylation-based sequencing, we identified the key gene TOM70 and its modification sites. Subsequently, we generated a specific antibody against TOM70 K199 crotonylation to validate this modification. To explore the underlying mechanism, we constructed an adeno-associated virus (AAV) vector carrying a mutation at the TOM70 locus. Finally, we performed high-throughput drug screening to identify compounds that potentially bind to the TOM70 K199 crotonylated protein.

In this study, we found that the crotonylation of TOM70 was significantly increased in MI mice and hypoxic HUVECs. Quantitative analysis of crotonylation further identified K199 as the critical modification site. In vivo studies have shown that the TOM70 K199R mutant virus can improve cardiac function in mice with MI and promote angiogenesis. In vitro, transfection with the TOM70 K199R plasmid mitigated the hypoxia-induced reduction in tube-forming ability of HUVECs, whereas the K199Q plasmids exacerbated the damage. Mechanistically, acyl-coA synthetase short-chain family member 2 (ACSS2) serves as an upstream regulatory factor, upregulating TOM70 K199cr, leading to mitochondrial morphological abnormalities and dysfunction by inhibiting the mitochondrial import of MIC19. This inhibition ultimately worsens myocardial remodeling and impedes the revascularization process. Based on this mechanism, we identified parishin as specific inhibitor of TOM70 K199cr, which demonstrated efficacy in improving cardiac function and promoting revascularization.

We found that ACSS2 upregulates TOM70 K199cr, inhibits mitochondrial import of MIC19 protein, causes mitochondrial structural and functional damage, and suppresses angiogenesis, thereby aggravating the progression of myocardial infarction. Administration of parishin can inhibit this process, improve angiogenesis, and enhance cardiac function.