Induction of nitric oxide synthase expression by Vibrio vulnificus cytolysin.
The pore-forming cytolysin of Vibrio vulnificus (VVC) causes severe hypotension and vasodilatation in vivo. Under the condition of bacterial sepsis, large amounts of nitric oxide (NO) produced by inducible NO synthase (iNOS) can contribute to host-induced tissue damage causing hypotension and septic shock. In this study, we investigated the effect of purified VVC on NO production in mouse peritoneal macrophages. VVC induced NO production in the presence of interferon-gamma. Increased NO production was not affected by polymyxin B, and heat inactivation of cytolysin abolished the NO-inducing capability. NO production was induced at the same concentration range of cytolysin for pore formation, as evidenced by the release of preloaded 2-deoxy-d-[(3)H]glucose. At the higher concentrations of cytolysin causing the depletion of cellular ATP, no NO production was observed. Increased expression of iNOS and activation of NFkappaB by VVC were confirmed by Western blotting and gel shift assay, respectively. These results suggest the role of cytolysin as an inducer of iNOS and NO production in macrophage and as a possible virulence determinant in V. vulnificus infection.
Kang
Mi-Kyung
MK
Department of Biochemistry, Institutes for Medical Sciences, Chonju, 561-756, Republic of Korea.
Jhee
Eun-Chung
EC
Koo
Bon-Sun
BS
Yang
Jeong-Yeh
JY
Park
Byung-Hyun
BH
Kim
Jong-Suk
JS
Rho
Hye-Won
HW
Kim
Hyung-Rho
HR
Park
Jin-Woo
JW
D000818:Animals; D015153:Blotting, Western; D003603:Cytotoxins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D024202:Electrophoretic Mobility Shift Assay; D007371:Interferon-gamma / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D011112:Polymyxin B / Q000494:pharmacology; D014733:Vibrio / Q000472:pathogenicity*
D003603:Cytotoxins; D016328:NF-kappa B; D009569:Nitric Oxide; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D011112:Polymyxin B