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Diabetic nephropathy is the leading cause of end‐stage renal disease. Although dysfunction of podocytes, also termed glomerular visceral epithelial cells, is critically associated with diabetic nephropathy, the mechanism underlying podocyte dysfunction still remains obscure. Here, we identify that KDM6A, a histone lysine demethylase, reinforces diabetic podocyte dysfunction by creating a positive feedback loop through up‐regulation of its downstream target KLF10. Overexpression of KLF10 in podocytes not only represses multiple podocyte‐specific markers including nephrin, but also conversely increases KDM6A expression. We further show that KLF10 inhibits nephrin expression by directly binding to the gene promoter together with the recruitment of methyltransferase Dnmt1. Importantly, inactivation or knockout of either KDM6A or KLF10 in mice significantly suppresses diabetes‐induced proteinuria and kidney injury. Consistent with the notion, we also show that levels of both KDM6A and KLF10 proteins or mRNAs are substantially elevated in kidney tissues or in urinary exosomes of human diabetic nephropathy patients as compared with control subjects. Our findings therefore suggest that targeting the KDM6A–KLF10 feedback loop may be beneficial to attenuate diabetes‐induced kidney injury. Synopsis: Podocyte dysfunction is an early event in the development of diabetic nephropathy. This study reveals that activation of a KDM6A‐KLF10 positive feedback loop by hyperglycemia critically contributes to podocyte dysfunction. Blocking the KDM6A‐KLF10 signaling axis ameliorates diabetic kidney injury. Both KDM6A and KLF10 are up‐regulated in podocytes under diabetic conditions.Activation of the positive inter‐regulation between KDM6A and KLF10 results in repression of multiple podocyte‐specific marker proteins.Inactivation or podocyte‐specific knockout of KDM6A in mice attenuates diabetes‐induced kidney injury.Kidney injury is also reduced in KLF10‐knockout mice under diabetic conditions.Elevated levels of urinary exosomal KDM6A and KLF10 mRNAs are observed in human diabetic nephropathy patients relative to control subjects. [ABSTRACT FROM AUTHOR]

Diabetic nephropathy is one of the leading causes of end‐stage renal disease and creates heavy healthcare burdens globally. Dysfunction of mesangial cells and podocytes contributes to diabetic nephropathy. Dysregulation of signaling involved in renal development and regeneration may cause diabetic kidney damages. Growing evidences suggest the importance of dysregulated dickkopf‐1 (DKK1)/Wnt/ β‐catenin signaling pathways in the pathogenesis of diabetic glomerular injuries. The inhibition of Wnt signaling in injured mesangial cells is likely attributed to the high glucose‐induced Ras/Rac1 dependent superoxide formation. When DKK1, the cellular inhibitor of Wnt signaling, binds to the Kremen‐2 receptor, depositions of extracellular matrix increase in the mesangium of diabetic kidneys. Additionally, reactivation of Notch‐1 signaling has been implicated in podocytopathy during diabetic proteinuria development. Knocking down Notch‐1 alleviates vascular endothelial growth factor (VEGF) expression, nephrin repression and proteinuria in diabetic kidneys. It is also found that epigenetic modulations by histone deacetylase 4 (HDAC4) and miR‐29a could lead to diabetic nephropathy. High glucose increases the expression of HDAC4, which causes deacetylation with subsequent ubiquitination of nephrin. Overexpression of miR‐29a in diabetic transgenic mice would decrease the expression of HDAC4 and stabilize nephrin. Surprisingly, reprogramming or reactivation of signaling involved in renal development or regeneration often brings about diabetic glomerular sclerosis in mesangial cells and podocytes. Better knowledge about modifications of embryonic stem cell signaling will have a chance to implement strategically focused pharmacological research programs aiming to the development of new drugs for diabetic kidney injuries. Summary at a Glance: Dysregulation of signaling involved in renal development or regeneration often leads to diabetic nephropathy. Recent advances of these molecular mechanisms are discussed. [ABSTRACT FROM AUTHOR]