Zedoarondiol Inhibits Platelet-Derived Growth Factor-Induced Vascular Smooth Muscle Cells Proliferation via Regulating AMP-Activated Protein Kinase Signaling Pathway

Background/aims: Vascular smooth muscle cells (VSMCs) proliferation contributes significantly to atherosclerosis and in-stent restenosis. Platelet-derived growth factor-BB (PDGF-BB) plays a vital role in VSMCs proliferation. Zedoarondiol, a sesquiterpene lactone compound, has an anti-inflammatory activity. However, the role of zedoarondiol in PDGF-BB-mediated VSMCs proliferation remains unclear. In this study, we investigated the effects of zedoarondiol on PDGF-BB-induced VSMCs proliferation and explored the possible mechanisms.

Methods: The inhibitory effects of zedoarondiol on PDGF-BB-induced VSMCs proliferation were evaluated by direct cell counting and the Cell Counting Kit-8 (CCK-8) assay. DNA synthesis was examined by bromodeoxyuridine (BrdU) incorporation assay. Cell cycle was assessed by propidium iodide staining. Western blotting was performed to determine the expression of cyclin-dependent kinase 2 (CDK2), cyclin E, p53, p21, total and phosphorylated adenosine monophosphate-activated protein kinase (AMPK), acetyl CoA carboxylase (ACC), mammalian target of rapamycin (mTOR), and p70 ribosomal protein S6 kinase (p70S6K).

Results: Zedoarondiol suppressed PDGF-BB-induced VSMCs proliferation and DNA synthesis, and induced cell cycle arrest in G0/G1 phase. In addition, zedoarondiol activated AMPK and ACC, inhibited the phosphorylation of mTOR and p70S6K, increased the expression of p53 and p21, and decreased the expression of CDK2 and cyclin E. Compound C (an AMPK Inhibitor) abrogated, whereas 5-aminoimidazole-4-carboxamide 1-β-ribofuranoside (AICAR, an AMPK Activator) enhanced zedoarondiol-mediated inhibition of VSMCs proliferation and DNA synthesis.

Conclusion: Zedoarondiol inhibits PDGF-BB-induced VSMCs proliferation via AMPK-mediated down-regulation of the mTOR/p70S6K pathway and up-regulation of the p53/p21 pathway. These findings suggest that zedoarondiol might be a promising compound against atherosclerosis and in-stent restenosis.