Figure 5.

STAT3 regulation by PDGF induction in vascular smooth muscle cells (VSMCs). (a) STAT3 localization by immunofluorescence microscopy. VSMCs were induced by 20 ng ml⁻¹ PDGF for 30 min±pre-incubation with 500 μM scoparone for 4 h and were processed for immunofluorescence staining using antibodies against pSTAT3 (Y705) or STAT3. Cell nuclei were stained with DAPI, and confocal images were obtained and merged. (b) Western blot analysis of Jak2 and Src protein expression. (c) Proposed scheme representing that scoparone can inhibit VSMC proliferation by inhibiting STAT 3 activation mediated by a growth factor. Total proteins were isolated from VSMCs induced by 20 ng ml⁻¹ PDGF±200 μM scoparone for different durations (0–24 h), and the total proteins were used for western blot analysis. β-Actin was used as a loading control.