TY - JOUR
T1 - Haemolysin produced by Vibrio mimicus activates two Cl- secretory pathways in cultured ntestinal-like Caco-2 cells
AU - Takahashi, Akira
AU - Miyoshi, Shin Ichi
AU - Takata, Noriko
AU - Nakano, Masayuki
AU - Hamamoto, Akiko
AU - Mawatari, Kazuaki
AU - Harada, Nagakatsu
AU - Shinoda, Sumio
AU - Nakaya, Yutaka
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2007/3
Y1 - 2007/3
N2 - Haemolysin (VMH) is a virulent factor produced by Vibrio mimicus, a human pathogen that causes diarrhoea. As intestinal epithelial cells are the primary targets of haemolysin, we investigated its effects on ion transport in human colonic epithelial Caco-2 cells. VMH increased the cellular short circuit current (Isc), used to estimated ion fluxes, and 125I efflux of the cells. The VMH-induced increases in Isc and 125I efflux were suppressed by depleting Ca2± from the medium or by pretreating the cells with BAPTA-AM or by Rp-adenosin 3′,5′-cyclic monophosphorothioate triethylammonium salt (Rp-cAMPS). The Cl - channel inhibitors 4,4′-disothiocyanatostibene-2,2′-disulfonic acid (DIDS), glybenclamide, and 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) suppressed the VMH-induced increases in Isc and 125I efflux. Moreover, VMH increased the intracellular concentrations of Ca2± and cAMP. Thus, VMH stimulates Caco-2 cells to secrete Cl- by activating both Ca2± -dependent and cAMP-dependent Cl- secretion mechanisms. VMH forms ion-permeable pores in the lipid bilayer that are non-selectively permeable to small ions. However, the ion permeability of these pores was not inhibited by glybenclamide and DIDS, and VMH did not change the cell membrane potential. These observations indicate that the pores formed on the cell membrane by VMH are unlikely to be involved in VMH-induced Cl- secretion. Notably, VMH stimulated fluid accumulation in the iliac loop test that was fully suppressed by a combination of DIDS and glybenclamide. Thus, Ca2± -dependent and cAMP-dependent Cl- secretion may be important therapeutic targets with regard to the diarrhoea that is induced by Vibrio mimicus.
AB - Haemolysin (VMH) is a virulent factor produced by Vibrio mimicus, a human pathogen that causes diarrhoea. As intestinal epithelial cells are the primary targets of haemolysin, we investigated its effects on ion transport in human colonic epithelial Caco-2 cells. VMH increased the cellular short circuit current (Isc), used to estimated ion fluxes, and 125I efflux of the cells. The VMH-induced increases in Isc and 125I efflux were suppressed by depleting Ca2± from the medium or by pretreating the cells with BAPTA-AM or by Rp-adenosin 3′,5′-cyclic monophosphorothioate triethylammonium salt (Rp-cAMPS). The Cl - channel inhibitors 4,4′-disothiocyanatostibene-2,2′-disulfonic acid (DIDS), glybenclamide, and 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) suppressed the VMH-induced increases in Isc and 125I efflux. Moreover, VMH increased the intracellular concentrations of Ca2± and cAMP. Thus, VMH stimulates Caco-2 cells to secrete Cl- by activating both Ca2± -dependent and cAMP-dependent Cl- secretion mechanisms. VMH forms ion-permeable pores in the lipid bilayer that are non-selectively permeable to small ions. However, the ion permeability of these pores was not inhibited by glybenclamide and DIDS, and VMH did not change the cell membrane potential. These observations indicate that the pores formed on the cell membrane by VMH are unlikely to be involved in VMH-induced Cl- secretion. Notably, VMH stimulated fluid accumulation in the iliac loop test that was fully suppressed by a combination of DIDS and glybenclamide. Thus, Ca2± -dependent and cAMP-dependent Cl- secretion may be important therapeutic targets with regard to the diarrhoea that is induced by Vibrio mimicus.
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U2 - 10.1111/j.1462-5822.2006.00809.x
DO - 10.1111/j.1462-5822.2006.00809.x
M3 - Article
C2 - 17026482
AN - SCOPUS:33846910477
VL - 9
SP - 583
EP - 595
JO - Cellular Microbiology
JF - Cellular Microbiology
SN - 1462-5814
IS - 3
ER -