Targeting TFAM K76 acetylation attenuates mitochondrial dysfunction and kidney injury in diabetic kidney disease.

BACKGROUND: Mitochondrial dysfunction is a hallmark of diabetic kidney disease (DKD), yet its regulatory mechanisms remain poorly defined. Mitochondrial transcription factor A (TFAM), a central regulator of mitochondrial homeostasis, undergoes lysine 76 (K76) acetylation, but the functional significance of this modification in DKD has not been established. METHODS: We collected kidney tissues from DKD patients and DKD mice, and assessed TFAM acetylation in HK-2 cells and primary renal tubular cells under high-glucose conditions. In addition, to investigate the potential mechanism of TFAM acetylation in mitochondrial damage within the kidney, we explored relevant pathways using proteomics and utilized streptozotocin (STZ)-induced DKD mouse models with tubular-specific expression of TFAM wild-type and mutant forms to examine kidney injury. Moreover, we identified TFAM K76 acetylation-specific inhibitors through high-throughput virtual screening and thoroughly validated them in HK-2 cells, primary cells, and DKD mice, confirming the critical role of TFAM acetylation in DKD-related kidney injury. RESULTS: Here, we identify TFAM K76 acetylation as a critical mediator of mitochondrial injury in DKD. TFAM K76 acetylation was markedly elevated in kidney tissues from DKD patients and diabetic mouse models, correlating with mitochondrial damage, inflammation, and fibrosis under hyperglycemic conditions. In vivo, overexpression of acetylation-mimetic TFAM K76Q in renal tubular epithelial cells aggravated renal injury and ultrastructural damage, whereas its deacetylation attenuated these effects. Mechanistically, TFAM K76 acetylation impaired oxidative phosphorylation and excessively activated autophagy, further exacerbating mitochondrial damage. We identified sirtuin 3 (SIRT3) as an upstream deacetylase that regulates this modification. Importantly, through high-throughput virtual screening, we discovered a novel small-molecule inhibitor (C14) that selectively reduces TFAM K76 acetylation and effectively alleviates hyperglycemia-induced mitochondrial dysfunction, inflammation, and fibrosis in both in vitro and in vivo models. CONCLUSIONS: Collectively, our findings define TFAM K76 acetylation as a pathogenic driver of DKD and propose C14 as a promising therapeutic candidate targeting mitochondrial metabolism.