title: VvpM, an extracellular metalloprotease of Vibrio vulnificus, induces apoptotic death of human cells.
abstract: A pathogenic bacterium, Vibrio vulnificus produces various extracellular proteases including the elastolytic metalloprotease, VvpE. In silico analysis of its genome revealed a VvpE-homologous protease, VvpM whose proteolytic activity was abolished by specific inhibitors against metalloproteases. To investigate whether this newly identified protease has pathogenic role in host interaction in addition to proteolytic role, human cell lines were incubated with recombinant VvpM (rVvpM). rVvpM-challenged cells showed typical morphological changes found in cells under apoptosis. Apoptotic cell death was further evidenced by estimating the Annexin V-stained cells, whose proportions were dependent upon the concentrations of rVvpM treated to human cells. To elucidate the signaling pathway for VvpM-induced apoptosis, three MAPKs were tested if their activation were mediated by rVvpM. ERK1/2 was phosphorylated by treatment of rVvpM and rVvpM-induced cell death was blocked by a specific inhibitor against ERK1/2. In rVvpM-treated cells, the cytosolic levels of cytochrome c were increased in a VvpM concentration-dependent manner, while the levels of cytochrome c in mitochondria were decreased. Cell deaths were accompanied by apparent cleavages of procaspases-9 and -3 to the active caspases-9 and -3, respectively. Therefore, this study demonstrates that an extracellular metalloprotease of V. vulnificus, VvpM induces apoptosis of human cells via a pathway consisting of ERK activation, cytochrome c release, and then activation of caspases-9 and -3.
authors.affiliation: The Department of Life Science, Sogang University, Seoul, 121-742, Republic of Korea.
authors.forename: Mi-Ae
authors.initials: MA
authors.lastname: Lee
authors.forename: Jeong-A
authors.initials: JA
authors.lastname: Kim
authors.forename: Yu Jin
authors.initials: YJ
authors.lastname: Yang
authors.forename: Mee-Young
authors.initials: MY
authors.lastname: Shin
authors.forename: Soon-Jung
authors.initials: SJ
authors.lastname: Park
authors.forename: Kyu-Ho
authors.initials: KH
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D017304:Annexin A5 / Q000032:analysis; D017209:Apoptosis / Q000502:physiology; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D003198:Computer Simulation; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004789:Enzyme Activation; D045325:HCT116 Cells; D019073:HT29 Cells; D006801:Humans; D045726:Metalloproteases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction; D041261:Vibrio vulnificus / Q000201:enzymology* / Q000472:pathogenicity*
chemical_list: D017304:Annexin A5; D001426:Bacterial Proteins; D011994:Recombinant Proteins; D045304:Cytochromes c; D045726:Metalloproteases; D053148:Caspase 3; D053453:Caspase 9