title: Expression of hepatocyte growth factor activator inhibitor type 1 in endothelial cells.
abstract: Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is an integral membrane Kunitz-type serine proteinase inhibitor initially identified as a potent inhibitor of hepatocyte growth factor activator (HGFA). HGFA is a serum proteinase that is critically involved in the activation of hepatocyte growth factor/scatter factor (HGF/SF) in injured tissue. Previous studies have shown that HAI-1 is expressed on the basolateral surface of various epithelial cells. In this study, we analyzed the expression of HAI-1 in human endothelial cells. Immunohistochemically, HAI-1 protein was observed in the endothelial cells of capillaries, venules and lymph vessels. On the other hand, arterial endothelial cells were poorly stained for HAI-1. Mesothelial cells on the serous surface were also positively immunostained. The endothelial expression of HAI-1 was also examined in cultured human endothelial cells of various origins, such as umbilical vein, microvessels and aorta. Notably, in accordance with the results of immunohistochemistry, HAI-1 mRNA and protein levels were high in the endothelial cells derived from umbilical vein and were hardly detectable in those derived from aorta. A low but distinct level of HAI-1 expression was also observed in endothelial cells from microvessels. As these HAI-1-positive endothelial cells also expressed MET tyrosine kinase, the specific receptor of HGF/SF, it is conceivable that HAI-1 might have an important regulatory role in the HGF/SF-MET signaling axis of endothelial cells, which could be involved in the process of angiogenesis.
authors.affiliation: Section of Oncopathology and Regenerative Biology, Department of Pathology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Akiyama
authors.forename: Miyuki
authors.initials: M
authors.lastname: Nagai
authors.forename: Wataru
authors.initials: W
authors.lastname: Komaki
authors.forename: Kousuke
authors.initials: K
authors.lastname: Marutsuka
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Asada
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kataoka
mesh_terms: D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology*; D017228:Hepatocyte Growth Factor / Q000378:metabolism / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D009389:Neovascularization, Pathologic / Q000235:genetics; D053491:Proteinase Inhibitory Proteins, Secretory; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019859:Proto-Oncogene Proteins c-met; D012333:RNA, Messenger / Q000378:metabolism; D017978:Receptors, Growth Factor / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction
chemical_list: D008562:Membrane Glycoproteins; D053491:Proteinase Inhibitory Proteins, Secretory; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; C109149:SPINT1 protein, human; D017228:Hepatocyte Growth Factor; C491743:MET protein, human; D019859:Proto-Oncogene Proteins c-met