title: Proteomic analysis of hypoxia-induced tube breakdown of an in vitro capillary model composed of HUVECs: potential role of p38-regulated reduction of HSP27.
abstract: We recently reported that hypoxia could induce the breakdown of capillary-like tubes formed by human umbilical vein endothelial cells (HUVECs) and that this breakdown was regulated by p38 and not by a caspase cascade, although the exact molecular mechanisms remain unknown. The aim of this study was to identify proteins that regulated hypoxia-induced tube breakdown through p38-regulated and caspase-independent mechanisms. The involvement of adhesion proteins, integrins, VE-cadherin, PECAM-1, and occludin was first investigated. Although some of these proteins decreased after hypoxia, none of them met the conditions of being quantitatively restored by p38 inhibition but not by caspase inhibition. We then conducted 2-D DIGE coupled with MALDI-TOF/TOF-MS to identify altered protein expression. The differential proteomic analysis of tube-forming HUVECs treated with normoxia or hypoxia and treated with hypoxia in the presence or absence of SB203580, a specific p38 inhibitor, revealed the involvement of heat shock proteins in this tube breakdown. We also confirmed that the amount of HSP27 and HSP70 changed in a p38-regulated and caspase-independent manner during hypoxia. Knocking down HSP27 expression using RNAi further augmented hypoxia-induced tube breakdown. Taken together, it was shown that p38-regulated and caspase-independent reduction of HSP27 plays an important role in hypoxia-induced tube breakdown.
authors.affiliation: Laboratory of Cell and Molecular Biology of Aging, Department of Food and Nutritional Sciences, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Eguchi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Naitou
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kunimasa
authors.forename: Rie
authors.initials: R
authors.lastname: Ayuzawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Fujimori
authors.forename: Norio
authors.initials: N
authors.lastname: Ohashi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kaji
authors.forename: Toshiro
authors.initials: T
authors.lastname: Ohta
mesh_terms: D002196:Capillaries / Q000201:enzymology / Q000473:pathology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology / Q000473:pathology*; D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000502:physiology; D006360:Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D000860:Hypoxia / Q000201:enzymology / Q000473:pathology* / Q000503:physiopathology; D008954:Models, Biological; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism; D040901:Proteomics; D014471:Umbilical Veins / Q000166:cytology* / Q000201:enzymology / Q000473:pathology; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology*
chemical_list: D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D020543:Proteome; D048051:p38 Mitogen-Activated Protein Kinases