Anthocyanidins, novel FAK inhibitors, attenuate PDGF-BB-induced aortic smooth muscle cell migration and neointima formation.

Aims: Abnormal migration of human aortic smooth muscle cells (HASMCs) causes intimal thickening of the aorta, a pivotal step in atherosclerotic development. Although many studies have demonstrated that high anthocynidins intake confers protective effects against atherosclerosis, the direct molecular targets, and mechanisms of action responsible remain unclear. Here, we investigated the preventive effect of anthocyanidins on atherosclerosis and the underlying mechanisms involved.

Methods And Results: We analysed six major anthocyanidins, and found that petunidin exhibited the most potent inhibitory effects against platelet-derived growth factor (PDGF)-BB-induced HASMC migration in the Boyden chamber and wound healing assays. Petunidin also suppressed PDGF-BB-induced ex vivo rat aortic sprouting and in vivo rat neointima formation. Western blot analysis showed that petunidin inhibited PDGF-BB-induced phosphorylation of focal adhesion kinase (FAK) at the low concentration of 5 µM, whereas phosphorylation of Src, mitogen-activated protein kinases, and Akt was only slightly inhibited at 20 µM. In vitro and ex vivo FAK activity assays demonstrated that petunidin directly suppresses FAK activity by binding in an ATP non-competitive manner. Moreover, anthocyanidins that reduced HASMC migration also inhibited PDGF-BB-induced FAK phosphorylation, F-actin reduction, and FAK activity, and directly bound with FAK. PDGF-BB-induced migration, F-actin reduction by HASMCs, and ex vivo aortic sprouting were all inhibited by treatment with a commercial FAK inhibitor, PF-228.

Conclusion: The results of the present study demonstrate that anthocyanidins can directly bind with and suppress the activity of FAK with atherosclerosis-preventive effects.