title: Matrix metalloprotein-9 activation under cell-to-cell interaction between endothelial cells and monocytes: possible role of hypoxia and tumor necrosis factor-α.
abstract: Matrix metalloproteinase (MMP)-9 plays an important role in cardiovascular events. However, the mechanisms underlying in vivo activation of MMP-9 are largely unknown. We investigated the secretion and activation of MMP-9 under a cell-to-cell interaction, and the effects of hypoxia and cytokine. Human umbilical vein endothelial cell (HUVEC) and THP-1 (human monocyte cell line) were cultured individually, or cocultured under normoxic and hypoxic conditions. In a coculture of HUVEC and THP-1, proMMP-9 secretion was increased twofold compared with individual culture of HUVEC and THP-1, whereas MMP-2 secretion was unchanged. The increase in proMMP-9 secretion was suppressed by antiadhesion molecule antibodies and mitogen-activated protein kinase inhibitors, PD98059 (MAPK/ERK kinase1 inhibitor) and SP600125 (Jun N-terminal kinase inhibitor). ProMMP-9 secretion was increased by tumor necrosis factor (TNF)-α at 50 ng/ml (P < 0.05) but was not activated under normoxic (20%) conditions. ProMMP-9 in coculture was activated under hypoxic (<1%) conditions, and was potentiated by TNF-α (both P < 0.05). To further investigate the mechanism of hypoxia-induced MMP-9 activation, heat shock protein (Hsp)90, which was suggested to be related to MMP-9 activation, was measured by Western blot analysis. The ratio of Hsp90 to glyceraldehyde-3-phosphate dehydrogenase was increased in hypoxic (<1%) coculture conditions with TNF-α (P < 0.05). Treatment with geldanamycin and 17-DMAG (Hsp90 inhibitor) suppressed the active form of MMP-9. Cell-to-cell interaction between endothelial cells and monocytes promotes proMMP-9 synthesis and secretion. Hypoxia and inflammation are suggested to play an important role in activating proMMP-9, presumably via Hsp90.
authors.affiliation: Department of Cardiology, Hirosaki University Graduate School of Medicine, 5-Zaifu-cho, Hirosaki, 036-8562, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Osanai
authors.forename: Fumie
authors.initials: F
authors.lastname: Nishizaki
authors.forename: Takanori
authors.initials: T
authors.lastname: Sukekawa
authors.forename: Kei
authors.initials: K
authors.lastname: Izumiyama
authors.forename: Shigeki
authors.initials: S
authors.lastname: Sagara
authors.forename: Ken
authors.initials: K
authors.lastname: Okumura
mesh_terms: D002450:Cell Communication / Q000187:drug effects; D015687:Cell Hypoxia; D018920:Coculture Techniques; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects / Q000201:enzymology*; D019007:P-Selectin / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D020298:U937 Cells
chemical_list: D004792:Enzyme Precursors; D018841:HSP90 Heat-Shock Proteins; D019007:P-Selectin; D047428:Protein Kinase Inhibitors; C546937:SELP protein, human; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D020928:Mitogen-Activated Protein Kinases; C120487:pro-matrix metalloproteinase 9; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9