TGFβ induces Schwann cell proliferation but promotes epithelial cell differentiation. (A) Morphology of growth-arrested (cultured in defined medium [DM] alone), proliferating (TGFβ), and differentiated (dbcAMP) rat Schwann cells. (B and G) BrdU incorporation in rat Schwann cells (B) and in WB-F344 cells (G) cultured in DM or treated with TGFβ (BrdU, green; DAPI, blue; double stain, turquoise), and graph representing the percentage of BrdU-positive cells. (C) Western blot analysis of cyclin D1 in lysates of rat Schwann cells cultured in DM (set to 100%) or treated with TGFβ. (B, C, and G) n = 3. (D) Western blot analysis of periaxin, PMP22 (*, P = 0.032; one-tailed t test), and P0 in rat Schwann cells cultured in DM treated with TGFβ (T) or dbcAMP (db; set to 100%). n ≥ 3. (E) Morphology of WB-F344 cells in DM alone or treated with TGFβ. (F) Immunostaining of SMA (green) and DAPI (blue) labeling of WB-F344 cells cultured in DM or treated with TGFβ. (H) Western blot analysis of SMA in WB-F344 cells cultured in DM or treated with TGFβ. For Western blot analyses, β-actin was used as loading control, and graphs represent the densitometry of the protein of interest normalized to the loading control. Statistical analyses were performed using two-tailed t tests on at least three independent experiments, unless mentioned otherwise. Error bars represent SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001.