Membrane cholesterol is required for activity of Vibrio vulnificus cytolysin
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O RI G I NAL PAPE R
Membrane cholesterol is required for activity of Vibrio vulniWcus cytolysin Hong-Nu Yu · Young-Rae Lee · Kwang-Hyun Park · So-Young Rah · Eun-Mi Noh · Eun-Kyung Song · Myung-Kwan Han · Byeong-Soo Kim · Sung-Ho Lee · Jong-Suk Kim
Received: 29 September 2006 / Revised: 3 January 2007 / Accepted: 15 January 2007 / Published online: 7 February 2007 © Springer-Verlag 2007
Abstract Vibrio vulniWcus cytolysin (VVC) forms a pore in the plasma membrane and induces cytolysis of various cells including erythrocytes, neutrophil and endothelial cells. The cytolytic activity of VVC is inhibited by exogenously added cholesterol, suggesting that membrane cholesterol might be required for VVC cytolytic activity. However, there is no direct evidence that membrane cholesterol is involved in VVC-induced cytolysis. Herein we demonstrate that membrane cholesterol is required for binding of VVC to the plasma membrane. Membrane cholesterol depletion with methyl--cyclodextrin inhibited VVC-induced K+ release, 2-deoxy glucose release and Ca2+ inXux, which are indicators of VVC pore formation. The cholesterol depletion-induced blockage of VVC cytolysis was due to the inhibition of VVC binding to membrane. These Wndings suggest that interaction with cholesterol is required for activity of VVC. Hong-Nu Yu, andYoung-Rae Lee have equally contributed to this study. H.-N. Yu · Y.-R. Lee · K.-H. Park · S.-Y. Rah · E.-M. Noh · J.-S. Kim (&) Department of Biochemistry, Institute of Medical Science, Chonbuk National University Medical School, Jeonju, South Korea e-mail: [email protected] E.-K. Song · M.-K. Han Department of Microbiology and Immunology, Institute of Medical Science, Chonbuk National University Medical School, Jeonju, South Korea B.-S. Kim · S.-H. Lee Department of Companion and Laboratory Animal Science, Research Center for Transgenic Cloned Pigs, Kongju National University, Yesan, South Korea
Keywords V. vulniWcus cytolysin · Cholesterol · Methyl--cyclodextrin Abbreviations VVC V. vulniWcus cytolysin CDCs Cholesterol-dependent cytolysins MCD Methyl--cyclodextrin MTT 3,4,5-Dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide
Introduction The halophilic bacterium Vibrio vulniWcus (V. vulniWcus) is known to be a life-threatening pathogen that causes septicemia and serious wound infection in human. V. vulniWcus infection is characterized by the high fatality rates of ca. 60% and the primary attack against persons who are immunocompromised or have underlying diseases such as liver cirrhosis or hemochromatosis (Hollis et al. 1976; Blake et al. 1979; Park et al. 1991; Oliver and Bockian 1995). V. vulniWcus cytolysin (VVC) has been regarded as a powerful virulence determinant for V. vulniWcus infection (Gray and Kreger 1985). VVC showed hemolytic and cytolytic activity against various cell type (Kreger and Lockwood 1981; Park et al. 1996; Lee et al. 2004). The hemolysis and cytolysis is induced by formation of small pores in erythrocyte or other cell membrane (Kim et al. 1993). A group of pore forming toxins, wh
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