Altered expression of the TGFβ-Smad2/3 signaling pathway in GM-injured kidneys as well as Tbx1-knockdown NRK cells. TGF-β mRNA expression was markedly increased in the kidneys of the GM-7d group (A). **, P < 0.01, vs. GM-0d, -21d and CTRL groups. Representative Western blot and quantitative data for p-Smad2/3 (B) and p-Smad1/5/8 (C) in rat kidney tissues. Increased p-Smad2/3 levels and reduced p-Smad1/5/8 levels were detected in the GM-7d group.**, P < 0.01 vs. GM-0d and GM-21d groups. Results are representative of at least three independent experiments. (D-F) NRK cells transiently transfected with Tbx1-specific siRNA (Tbx1-siRNA) or scramble siRNA. Tbx1 mRNA expression was determined by real-time PCR (D), and Tbx1 protein expression was detected by Western blotting (E). As detected by real-time RT-PCR and Western blotting, Tbx1 gene knockdown has resulted in decreased expression of TGF-β mRNA (F) and p-Smad2/3 protein (G), and increased Smad1/5/8 protein expression (H). β-actin was used as a control. **, P < 0.01 vs. CTRL group. TGF-β, transforming growth factor-beta gene.