Abstract

While the histone lysine methyltransferase (KMT) family responsible for posttranslational modification has been reported to regulate multiple diseases progression like tumor and cardiovascular disease, its role in renal fibrosis progression is not completely understood. Here, via TGF‐β‐treated HK‐2 cells and an in vivo unilateral ureteral obstruction mice model, the histone lysine methyltransferase family was screened and the upregulated expression of KMT5a was identified in these renal fibrosis models. Interference assays using lentivirus transfection in HK‐2 cells and transgenic mice displayed that KMT5a silencing in HK‐2 cells impeded macrophage chemotaxis. Moreover, in vivo, transgenic KMT5a knockout inhibited macrophage infiltration, which contributed to the suppression of renal fibrosis progression. Mechanistically, by immunoprecipitation assays and mass spectrometry, we discovered that KMT5a could interact with and stabilize the transcription factor IRF3 to regulate macrophage chemotaxis and infiltration in renal tissues, which accelerated renal fibrosis progression. Notably, we confirmed that a small molecular inhibitor of KMT5a, UNC0379, reduced IRF3 protein levels and macrophage chemotaxis, thus suppressing renal fibrosis, in vitro and in vivo. Therefore, this study presented KMT5a as a mediator of renal fibrosis progression, an effect that was reversed by the KMT5a inhibitor UNC0379, which provided evidence of a novel target and potential drug for inhibiting renal fibrosis progression. In renal tubular epithelial cells, TGF‐β‐induced upregulation of KMT5A enhances IRF3 methylation and protein stability. This augments chemokine transcription, leading to elevated production and secretion of CCL2, CCL3, and CCL7. These chemokines collectively promote macrophage chemotaxis and infiltration, thereby accelerating the progression of renal fibrosis.