SMAD3 and renal fibrosis: In this context, some molecules, such as Klotho, BMP-7, and Krüppel-like factor 15 (KLF15), have been shown to protect against renal fibrosis in the kidney following chronic injury (Castillo 2023; Li et al. 2015; Wang et al. 2019) Among them, KLF15 is a transcription factor that suppresses renal fibrosis by inhibiting multiple signaling pathways such as the Wnt/β-catenin and TGF-β1/Smad3.