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This Article Full Text Full Text (PDF) All Versions of this Article: 297/4/L706    most recent 90598.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Meoli, D. F. Articles by White, R. J. PubMed PubMed Citation Articles by Meoli, D. F. Articles by White, R. J.

Thrombin induces fibronectin-specific migration of pulmonary microvascular endothelial cells: requirement of calcium/calmodulin-dependent protein kinase II

Aab Cardiovascular Research Institute and Department of Pulmonary and Critical Care Medicine, University of Rochester, Rochester, New York

Submitted 2 December 2008 ; accepted in final form 27 July 2009

Pulmonary arterial hypertension (PAH) is a progressive disease of excess vasoconstriction and vascular cell proliferation that results in increased pulmonary vascular resistance and right heart failure. We have previously shown (66) that tissue factor expression is increased in the abnormal vessels of patients and rats with PAH. We hypothesized that tissue factor and its downstream mediator, thrombin, would promote migration of endothelial cells (EC) and the vascular pathology of PAH. Immunostaining revealed EC and a fibronectin-enriched matrix within the "plexiform-like" lesions in a rat model of severe PAH. In a modified Boyden assay, protease-activated receptor 1 (PAR1; thrombin receptor) stimulation by agonist peptide or thrombin induced pulmonary microvascular EC (PMVEC) migration when the cells were interacting with fibronectin, but not with other extracellular matrix proteins. Thrombin/fibronectin-induced migration was confirmed in wound healing and angiogenesis assays and was abrogated by the PAR1 antagonist SCH79797 and soluble RGD peptide. This fibronectin dependence was unique to PAR1 activation; other EC agonists evaluated did not induce migration on any matrix, and 10% FBS stimulated similar levels of migration on all matrix proteins tested. Thrombin/fibronectin stimulated autophosphorylation of calcium/calmodulin dependent protein kinase II (CaMKII) in PMVEC, and inhibitors of CaMKII blocked thrombin-induced migration on fibronectin, but had no effect on migration induced by 10% FBS. In contrast, EC isolated from the proximal pulmonary artery migrated in response to most agonists independent of the matrix substrate. Our findings illustrate EC heterogeneity in a single tissue and indicate a novel role for CaMKII in mediating EC migration. Because PMVEC have been shown to have impressive proliferative potential, thrombin/fibronectin-stimulated migration of these cells to a site of injured endothelium is a potential mechanism by which thrombin contributes to the development of vascular lesions in PAH.

pulmonary hypertension; plexiform lesions; fibronectin