Fig. 1.

Fluid shear stress dynamically regulates both transforming growth factor (TGF)-β1 gene expression and downstream SMAD3 activation via Notch4 involvement. Confluent monolayers of proximal tubule epithelial cells (PTECs) were subjected to either static or fluid shear (0.3, 2, or 4 dyn/cm²) conditions for the prescribed periods of time. TGF-β1 gene expression in shear-activated PTECs was quantified via qRT-PCR over the time period examined relative to static controls (A–C). Data represent means ± SE of n = 3 independent experiments. P < 0.05. The activation of both canonical SMAD3 signaling and Notch4 was assessed via immunoblotting (D–F). SC, static control. Western blots are representative of 3 independent experiments, all revealing similar results.