title: Microtubule dynamics control HGF-induced lung endothelial barrier enhancement.
abstract: Microtubules (MT) play a vital role in many cellular functions, but their role in peripheral actin cytoskeletal dynamics which is essential for control of endothelial barrier and monolayer integrity is less understood. We have previously described the enhancement of lung endothelial cell (EC) barrier by hepatocyte growth factor (HGF) which was associated with Rac1-mediated remodeling of actin cytoskeleton. This study investigated involvement of MT-dependent mechanisms in the HGF-induced enhancement of EC barrier. HGF-induced Rac1 activation was accompanied by phosphorylation of stathmin, a regulator of MT dynamics. HGF also stimulated MT peripheral growth monitored by time lapse imaging and tracking analysis of EB-1-decorated MT growing tips, and increased the pool of acetylated tubulin. These effects were abolished by EC pretreatment with HGF receptor inhibitor, downregulation of Rac1 pathway, or by expression of a stathmin-S63A phosphorylation deficient mutant. Expression of stathmin-S63A abolished the HGF protective effects against thrombin-induced activation of RhoA cascade, permeability increase, and EC barrier dysfunction. These results demonstrate a novel MT-dependent mechanism of HGF-induced EC barrier regulation via Rac1/PAK1/stathmin-dependent control of MT dynamics.
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois, United States of America.
authors.forename: Xinyong
authors.initials: X
authors.lastname: Tian
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois, United States of America.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois, United States of America.
authors.forename: Nurgul
authors.initials: N
authors.lastname: Moldobaeva
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois, United States of America.
authors.forename: Nicolene
authors.initials: N
authors.lastname: Sarich
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois, United States of America.
authors.forename: Anna A
authors.initials: AA
authors.lastname: Birukova
mesh_terms: D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D017228:Hepatocyte Growth Factor / Q000502:physiology*; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000502:physiology*; D008870:Microtubules / Q000502:physiology*; D010766:Phosphorylation; D050777:Stathmin / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000502:physiology
chemical_list: D050777:Stathmin; D017228:Hepatocyte Growth Factor; D020830:rac1 GTP-Binding Protein