Nesfatin-1 attenuates renal interstitial fibrosis, oxidative stress, and inflammation through dual suppression of TGF-β1/Smad and NF-κB/GPR12 signaling.

Tubulointerstitial fibrosis is a key pathological driver of chronic kidney disease (CKD) progression. Nesfatin-1 is a neuropeptide known for its antioxidant and anti-inflammatory actions; however, its antifibrotic potential and associated signaling mechanisms remain insufficiently defined. This study evaluated the protective role of nesfatin-1 in unilateral ureteral obstruction (UUO) and examined its effects on TGF-β1-mediated fibroblast activation in NRK-49F cells. UUO-induced renal fibrosis in mice and TGF-β1-stimulated NRK-49F fibroblasts were used to assess the antifibrotic activity of nesfatin-1. Biochemical assays, histopathology, qRT-PCR, western blotting, flow cytometry, and immunofluorescence were performed to elucidate underlying mechanisms. Nesfatin-1 expression was significantly reduced in UUO kidneys and in TGF-β1-exposed fibroblasts. Exogenous nesfatin-1 decreased serum creatinine and blood urea nitrogen, alleviated tubular injury, limited ECM accumulation, and suppressed activation of the TGF-β1/Smad pathway. It also restored antioxidant gene expression and attenuated inflammatory markers in UUO mice. In NRK-49F cells, nesfatin-1 prevented TGF-β1-driven fibroblast-to-myofibroblast transformation, accompanied by downregulation of TGF-β/Smad signaling and normalization of GPR12 expression. These findings indicate that nesfatin-1 protects against renal fibrosis by modulating the TGF-β1/Smad and NF-κB/NLRP3 pathways. The normalization of GPR12 expression suggests a potential receptor-mediated mechanism contributing to its renoprotective effects.