alpha-Iso-Cubebene Inhibits PDGF-Induced Vascular Smooth Muscle Cell Proliferation by Suppressing Osteopontin Expression

作者：Jang Min A; Lee Seung Jin; Baek Seung Eun; Park So Youn; Choi Young Whan; Kim Chi Dae^*

来源：PLos One, 2017, 12(1): e0170699.

DOI：10.1371/journal.pone.0170699

alpha-Iso-cubebene (ICB) is a dibenzocyclooctadiene lignin contained in Schisandra chinensis (SC), a well-known medicinal herb that ameliorates cardiovascular symptoms. Thus, we examined the effect of ICB on vascular smooth muscle cell (VSMC) proliferation, a key feature of diverse vascular diseases. When VSMCs primary cultured from rat thoracic aorta were stimulated with PDGF (1-10 ng/ml), cell proliferation and osteopontin (OPN) expression were concomitantly up-regulated, but these effects were attenuated when cells were treated with MPIIIB10, a neutralizing monoclonal antibody for OPN. In aortic tissues exposed to PDGF, sprouting VSMC numbers increased, which was attenuated in tissues from OPN-deficient mice. Furthermore, VSMC proliferation and OPN expression induced by PDGF were attenuated dose-dependently by ICB (10 or 30 mu g/ml). Reporter assays conducted using OPN promoter-luciferase constructs showed that the promoter region 538-234 bp of the transcription start site was responsible for transcriptional activity enhancement by PDGF, which was significantly inhibited by ICB. Putative binding sites for AP-1 and C/EBP beta in the indicated promoter region were suggested by TF Search, and increased binding of AP-1 and C/EBPa in PDGF-treated VSMCs was demonstrated using a ChIP assay. The increased bindings of AP-1 and C/EBP into OPN promoter were attenuated by ICB. Moreover, the PDGF-induced expression of OPN was markedly attenuated in VSMCs transfected with siRNA for AP-1 and C/EBP beta. These results indicate that ICB inhibit VSMC proliferation by inhibiting the AP-1 and C/EBP beta signaling pathways and thus downregulating OPN expression.

• 出版日期2017-1-23