Vibrio parahaemolyticus thermostable direct hemolysin can induce an apoptotic cell death in Rat-1 cells from inside and outside of the cells.
Rat-1 cells exposed to Vibrio parahaemolyticus thermostable direct hemolysin (TDH) developed morphological changes including shrinkage of the cells and reduction in the size of nuclei. Cells either microinjected with TDH or transfected with the tdh gene also showed morphological changes similar to those induced by externally added toxin. Furthermore, TDH-exposed or tdh-transfected cells both showed chromatin condensation and DNA fragmentation which suggest cells undergoing apoptosis. In contrast, expression of a TDH mutant (R7) did not reveal any cytotoxic effects. We demonstrate that expressed TDH was distributed in the cytoplasm. The interleukin-1beta-converting enzyme-related protease inhibitor ZVAD-FMK did not inhibit TDH cytotoxicity. Our results suggest that TDH can induce its cytotoxicity both from outside and from inside the cells and killed the cells through apoptosis.
Naim
R
R
Department of Bacterial Infections, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Yanagihara
I
I
Iida
T
T
Honda
T
T
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D001427:Bacterial Toxins; D061945:Caspase Inhibitors; D002460:Cell Line; D048429:Cell Size / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D053938:DNA Fragmentation; D006460:Hemolysin Proteins / Q000235:genetics / Q000633:toxicity*; D006358:Hot Temperature; D008845:Microinjections; D051381:Rats; D014162:Transfection; D014736:Vibrio parahaemolyticus / Q000472:pathogenicity*
D000590:Amino Acid Chloromethyl Ketones; D001427:Bacterial Toxins; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D006460:Hemolysin Proteins; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C068489:thermostable direct hemolysin