Fig. 6.

Rapamycin induces TGF-β pathway activation through autophagy activation. a Immunoblottings for TGFβR-I, TGFβR-II, p-Smad3, Smad2/3, Smad7 and β-ACTIN were performed with cell lysates on day 1 in Fig. 5a, and representative data are shown. The histogram (lower) shows mean densitometric readings for the proteins normalized to Smad2/3 or β-ACTIN from three independent experiments. *p < 0.05; **p < 0.01. b Cell culture supernatant on day 1 in Fig. 5a was subjected to ELISA detection for TGF-β1 levels. Data are expressed as mean ± SD from three independent experiments. *p < 0.05; **p < 0.01. c Diagram summarizing the effects of rapamycin on endothelial cells undergoing stress-induced premature senescence (SIPS). Control (Ctr): untreated cells, bafilomycin A1 (BAF). SASP, senescence-associated secretory phenotype