ABHD11-Mediated mtDNA Transcription Restored Mitochondrial Function to Attenuate Cardiomyocyte Ferroptosis After Myocardial Infarction.

BACKGROUND

Cardiomyocytes exhibit marked susceptibility to ferroptosis after myocardial infarction (MI), rendering ferroptosis inhibition a promising therapeutic strategy to mitigate ischemic myocardial injury. Although mitochondrial dysfunction is recognized as a core driver of ferroptosis, the potential role of mitochondrial DNA transcription in regulating cardiomyocyte ferroptosis remains unexplored.

METHODS

To clarify the temporal role of the various modes of cell death in MI progression, we performed time-course echocardiography in MI models treated with various cell death inhibitors. To characterize the crucial process and molecular regulator in cardiomyocyte ferroptosis, we integrated RNA sequencing and single-nucleus RNA sequencing data from murine post-MI hearts and performed functional rescue experiments using mitochondrial protective agents. To determine the role of ABHD11 (αβ-hydrolase domain-containing protein 11) in cardiomyocyte ferroptosis and cardiac repair after MI, we used loss- and gain-of-function approaches. To elucidate the underlying mechanisms, we conducted transcriptomics, nontargeted lipidomics, site-specific mutagenesis, molecular docking, coimmunoprecipitation, native gel electrophoresis, proximity ligation assay, methylation-specific polymerase chain reaction, and chromatin immunoprecipitation assay.

RESULTS

We found that cardiac ferroptosis peaked at day 7 after MI and was enriched in peri-infarct cardiomyocytes. Mitochondrial dysfunction was a key driver of cardiomyocyte ferroptosis after MI, and the lipid enzyme ABHD11 was identified as a potential regulator of both processes. ABHD11 expression was consistently reduced in mouse and human MI hearts, and its transcription was repressed by DNMT1 (DNA methyltransferase 1)-mediated promoter hypermethylation. Functionally, cardiac-specific overexpression of ABHD11 markedly alleviated cardiomyocyte ferroptosis and improved cardiac function after MI. Conversely, loss of ABHD11 in adult mice exacerbated pathological cardiac remodeling and heart failure. Mechanistically, independent of its canonical enzymatic activities, ABHD11 acted as a mitochondrial DNA transcription coactivator by enhancing the TEFM (mitochondrial transcription elongation factor)-POLRMT (mitochondrial RNA polymerase) interaction. This promoted mitochondrial DNA transcription, restored mitochondrial function, and reduced reactive oxygen species/PUFA-PLs (polyunsaturated fatty acid-containing glycerophospholipids)-driven lipid peroxidation and 4-hydroxynonenal generation. The reduction in 4-hydroxynonenal stabilized YY1 (Yin Yang 1), which subsequently regulated key ferroptosis-driving genes governing iron deposition, reactive oxygen species production, and polyunsaturated fatty acid lipids accumulation, further inhibiting lipid peroxidation and ferroptosis, and ultimately promoting cardiac recovery after MI.

CONCLUSIONS

This study revealed that ABHD11-mediated mitochondrial DNA transcription attenuated cardiomyocyte ferroptosis after MI by orchestrating a mitochondrial-nuclear crosstalk, offering a novel therapeutic strategy for ischemic myocardial injury.