PAG1 aggravates diabetic nephropathy through TGF-β1/Smads-driven pyroptosis.

Phosphoprotein associated with glycosphingolipid-enriched microdomains 1 (PAG1) has been recognized as a biomarker for diabetic nephropathy (DN). This study aimed to elucidate the mechanism by which PAG1 influences DN. The expression and clinical significance of PAG1 in DN were assessed using bioinformatics analysis. PAG1 expression was validated in db/db mice and high glucose (HG)-treated human kidney-2 (HK-2) cells. Subsequently, PAG1 was knocked down in DN models to investigate its effects on DN progression, pyroptosis, and the transforming growth factorbeta 1 (TGF-β1)/Smads pathway. The TGF-β1/Smads pathway activator SRI-011381 was employed to further elucidate the role of PAG1 in DN regulation. Bioinformatics analysis revealed elevated PAG1 expression in DN samples, which correlated with various immune cells and pathways, such as chemokine pathway and cell cycle. This elevated expression was confirmed in animal and cell experiments. In db/db mice, PAG1 knockdown alleviated DN, reduced inflammatory factor levels, inhibited pyroptosis, and suppressed TGF-β1/Smads pathway. In vitro, PAG1 silencing promoted proliferation, inhibited apoptosis and fibrosis, reduced inflammatory and pyroptotic factor levels, and suppressed the TGF-β1/Smads pathway. These effects were reversed by SRI-011381 intervention. PAG1 promotes pyroptosis by upregulating the TGF-β1/Smads pathway, thereby exacerbating DN.