Background Diabetic nephropathy (DN) is prevalent in patients with diabetes. N6-methyladenosine (m6A) methylation has been found to cause modification of nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing (NLRP) 3, which is involved in cell pyroptosis and inflammation. WTAP is a key gene in modulating NLRP3 m6A. Methods In this study, WTAP was silenced or overexpressed in high glucose (HG)-treated HK-2 cells to determine its influence on pyroptosis, NLRP3 inflammasome-related proteins, and the release of pro-inflammatory cytokines. NLRP3 expression and m6A levels were assessed in the presence of WTAP shRNA (shWTAP). WTAP expression in HK-2 cells was examined with the introduction of C646, a histone acetyltransferase p300 inhibitor. Results We found that WTAP expression was enhanced in patients with DN and in HG-treated HK-2 cells. Knockdown of WTAP attenuated HG-induced cell pyroptosis and NLRP3-related pro-inflammatory cytokines in both HK-2 cells and db/db mice, whereas WTAP overexpression promoted these cellular processes in HK-2 cells. WTAP mediated the m6A of NLRP3 mRNA that was stabilized by insulin-like growth factor 2 mRNA binding protein 1. Histone acetyltransferase p300 regulated WTAP expression. WTAP mRNA levels were positively correlated with NLRP3 inflammasome components and pro-inflammatory cytokines. Conclusion Taken together, WTAP promotes the m6A methylation of NLRP3 mRNA to upregulate NLRP3 inflammasome activation, which further induces cell pyroptosis and inflammation.

Fibrosis, or the excess deposition of fibrous tissue, is a critical feature of chronic kidney disease. Here, using renal fibrotic rat as a model, which was established via 5/6 nephrectomy (Nx), the role of TMEM45A transmembrane protein in renal fibrosis was investigated. The results indicated that 5/6 Nx gradually led to histopathological abnormalities and loss of kidney function in rats, which correlated with upregulation of TMEM45A and Notch1. Interestingly, in NRK-49F renal cells, overexpression of TMEM45A resulted in up-regulation of extracellular matrix © 1996-2020 (ECM) components as well as induction of Notch-1 and Jagged-1. These effects were weakened by DAPT, an inhibitor of the Notch pathway, suggesting an important role of Notch signaling in mediating the functions of TMEM45A in NRK-49F cells Moreover, TMEM45A knockdown by TMEM45A siRNA in NRK-49F cells diminished TGF-β1-induced upregulation of ECM components, inflammatory cytokines, Notch-1 and Jagged-1. Correspondingly, TGF-beta 1 exhibited pro-fibrogenic like effect in NRK-49F cells and induced TMEM45A and Jagged1/Notch expression.Collectively, these results demonstrate that TMEM45A plays an important role in renal fibrosis by regulating ECM components and Jagged1/Notch pathway.TMEM45A is involved in renal fibrosis 595