Virtual screening and cellular validation of dolutegravir as a BRD9 inhibitor for attenuating pyroptosis in peritoneal mesothelial cells.

BACKGROUND: Peritoneal dialysis is an essential therapy for end-stage renal disease; however, long-term exposure to high-glucose dialysis solutions induces pyroptosis of peritoneal mesothelial cells, promoting peritoneal fibrosis and ultimately leading to technique failure. The involvement of the epigenetic regulator bromodomain-containing protein 9 (BRD9) in this process remains unclear. METHODS: Structure-based virtual screening of 3,447 FDA-approved drugs from the ZINC database identified dolutegravir as a candidate BRD9 inhibitor. Direct binding and inhibitory activity were validated using cellular thermal shift assays, IC(50) determination, and molecular docking. Under high-glucose conditions, the effects of dolutegravir on pyroptosis-related signaling and fibrosis markers in human mesothelial cells were assessed by Western blotting, ELISA, RT-qPCR, and flow cytometry. RESULTS: Dolutegravir directly bound to and inhibited BRD9. Under high-glucose stimulation, dolutegravir markedly suppressed NLRP3 inflammasome activation, reduced caspase-1 and gasdermin D cleavage, and decreased interleukin (IL)-1β and IL-18 maturation and release. Mechanistically, BRD9 inhibition accelerated nod-like receptor protein 3 (NLRP3) mRNA degradation and attenuated NLRP3-mediated secretion of the pro-fibrotic factor transforming growth factor-beta 1, leading to downregulation of fibrosis-related markers smooth muscle alpha-actin 2 and collagen type I alpha 1. CONCLUSION: This study identifies dolutegravir as a novel BRD9 inhibitor and demonstrates that BRD9 is a key regulator of high glucose-induced pyroptosis and pro-fibrotic signaling in mesothelial cells via modulation of NLRP3 mRNA stability. These findings suggest a new therapeutic strategy for preventing peritoneal fibrosis and highlight the potential of computational drug repurposing.