Article

Focal Adhesion Kinase Regulates Smooth Muscle Cell Recruitment to the Developing Vasculature

Department of Pathology, University of North Carolina, Chapel Hill, 27599-7525, USA.
Arteriosclerosis Thrombosis and Vascular Biology (Impact Factor: 5.53). 07/2011; 31(10):2193-202. DOI: 10.1161/ATVBAHA.111.232231
Source: PubMed

ABSTRACT The investment of newly formed endothelial cell tubes with differentiated smooth muscle cells (SMC) is critical for appropriate vessel formation, but the underlying mechanisms remain unknown. We previously showed that depletion of focal adhesion kinase (FAK) in the nkx2.5 expression domain led to aberrant outflow tract (OFT) morphogenesis and strove herein to determine the cell types and mechanisms involved.
We crossed fak(loxp) targeted mice with available Cre drivers to deplete FAK in OFT SMC (FAK(wnt) and FAK(nk)) or coronary SMC (FAK(cSMC)). In each case, depletion of FAK led to defective vasculogenesis that was incompatible with postnatal life. Immunohistochemical analysis of the mutant vascular structures revealed that FAK was not required for progenitor cell proliferation, survival, or differentiation into SMC but was necessary for subsequent SMC recruitment to developing vasculature. Using a novel FAK-null SMC culture model, we found that depletion of FAK did not influence SMC growth or survival, but blocked directional SMC motility and invasion toward the potent endothelial-derived chemokine, platelet-derived growth factor PDGFBB. FAK depletion resulted in unstable lamellipodial protrusions due to defective spatial-temporal activation of the small GTPase, Rac-1, and lack of Rac1-dependent recruitment of cortactin (an actin stabilizing protein) to the leading edge. Moreover, FAK null SMC exhibited a significant reduction in stimulated extracellular matrix degradation.
FAK drives PDGFBB-stimulated SMC chemotaxis/invasion and is essential for SMC to appropriately populate the aorticopulmonary septum and the coronary vascular plexus.

Download full-text

Full-text

Available from: Joan M Taylor, Mar 28, 2014
0 Followers
 · 
125 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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. We analyzed six major anthocyanidins, and found that petunidin exhibited the most potent inhibitory effects against platelet-derived growth factor (PDGF)-BB-induced HASMC migration in 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 FAK at the low concentration of 5 µM, whereas phosphorylation of Src, MAPKs and Akt were 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. The results of the present study demonstrate that anthocyanidins can directly bind with and suppress the activity of FAK with atherosclerosis-preventive effects.
    Cardiovascular Research 12/2013; DOI:10.1093/cvr/cvt337 · 5.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: During heart development, the epicardium, which originates from the proepicardial organ (PE), is a source of coronary vessels. The PE develops from the posterior visceral mesoderm of the pericardial coelom after stimulation with a combination of weak bone morphogenetic protein and strong fibroblast growth factor (FGF) signaling. PE-derived cells migrate across the heart surface to form the epicardial sheet, which subsequently seeds multipotent subepicardial mesenchymal cells via epithelial-mesenchymal transition, which is regulated by several signaling pathways including retinoic acid, FGF, sonic hedgehog, Wnt, transforming growth factor-β, and platelet-derived growth factor. Subepicardial endothelial progenitors eventually generate the coronary vascular plexus, which acquires an arterial or venous phenotype, connects with the sinus venosus and aortic sinuses, and then matures through the recruitment of vascular smooth muscle cells under the regulation of complex growth factor signaling pathways. These developmental programs might be activated in the adult heart after injury and play a role in the regeneration/repair of the myocardium.
    International review of cell and molecular biology 01/2013; 303:263-317. DOI:10.1016/B978-0-12-407697-6.00007-6 · 4.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pelargonidin is a natural red pigment found in fruits and vegetables, and has been reported to exhibit various effects potentially beneficial for human health. However, the possible preventive effects of pelargonidin toward atherosclerosis and mechanisms involved have not been investigated to date. Here, we compared the effects of pelargonidin and its glucoside-conjugated form, pelargonidin-3-glucoside (P3G), on proliferation and migration induced by platelet-derived growth factor (PDGF)-BB in human aortic smooth muscle cells (HASMCs). Pelargonidin, but not P3G, exhibited strong inhibitory effects against PDGF-BB-induced HASMC proliferation and migration, while suppressing PDGF-BB-induced ex vivo rat aortic ring sprouting. Immunoblot analysis revealed that pelargonidin inhibited PDGF-BB-induced phosphorylation of focal adhesion kinase (FAK) as well as F-actin reduction, whereas Src, mitogen-activated protein kinases (MAPKs) and Akt phosphorylation status were not altered. We also observed that the anti-proliferative and migratory effects of both pelargonidin and P3G corresponded with the extent of FAK inhibition. Both in vitro and ex vivo pull-down assays revealed that pelargonidin binds directly with FAK in an adenosine triphosphate-competitive manner, suggesting that FAK could be a molecular target of pelargonidin. Interestingly, pelargonidin did not exhibit inhibitory effects on the proliferation, migration or FAK phosphorylation of human umbilical vein endothelial cells (HUVECs). Taken together, our results suggest that pelargonidin exhibits potential preventive effects toward atherosclerosis through the attenuation of HASMC proliferation and migration, as well as aortic sprouting via the direct inhibition of FAK activity.
    Biochemical pharmacology 02/2014; DOI:10.1016/j.bcp.2014.02.015 · 4.65 Impact Factor