P300-mediated H3K18 acetylation triggers necroptosis via modulation of KRT18 transcription in diabetic nephropathyOA

Diabetic nephropathy(DN)is a major cause of end-stage renal disease.While glomerular damage is a known aspect of its pathology,tubular epithelial cell necroptosis also plays a crucial role in disease progression.Epigenetic modifications,particularly histone acetylation,have garnered attention for their role in the regulation of kidney damage-related gene expression.This study explores whether the histone acetyltransferase P300 regulates KRT18 expression via histone H3 lysine 18 acetylation(H3K18ac),driving tubular epithelial cell necroptosis and accelerating DN progression.We establish an STZ-induced diabetic nephropathy mouse model and a high glucose-treated HK-2 cell model.Western blot analysis,qPCR,immunohistochemistry,and AO/PI staining are employed to assess the expression levels of P300,H3K18ac,KRT18,and necroptosis-related proteins(RIPK1 and MLKL).Functional validation of the P300-KRT18 axis is performed using shRNA interference,overexpression,and the small molecule inhibitor C646.Both in vivo and in vitro models show significant upregulation of P300,H3K18ac,and KRT18,coupled with RIPK1/MLKL pathway activation and increased cell death.P300 knockdown or C646 treatment effectively inhibits H3K18ac and KRT18 expression,reducing necroptosis;KRT18 knockdown also alleviates P300 overexpression-induced cell death.Co-transfection with P300 overexpression and KRT18 interference demonstrates that KRT18 is a key downstream effector of P300-mediated necroptosis.In conclusion,P300 upregulates KRT18 expression through H3K18 acetylation,subsequently activating the RIPK1/MLKL pathway and promoting tubular epithelial cell necroptosis.The P300-KRT18 axis may serve as a novel epigenetic therapeutic target for DN,suggesting that epigenetic regulation could be a viable intervention strategy to delay DN progression.