title: Clostridium difficileToxin A Induces Reactive Oxygen Species Production and p38 MAPK Activation to Exert Cellular Toxicity in Neuronal Cells.
abstract: Clostridium difficilereleases two exotoxins, toxin A and toxin B, which disrupt the epithelial cell barrier in the gut to increase mucosal permeability and trigger inflammation with severe diarrhea. Many studies have suggested that enteric nerves are also directly involved in the progression of this toxin-mediated inflammation and diarrhea.C. difficiletoxin A is known to enhance neurotransmitter secretion, increase gut motility, and suppress sympathetic neurotransmission in the guinea pig colitis model. Although previous studies have examined the pathophysiological role of enteric nerves in gut inflammation, the direct effect of toxins on neuronal cells and the molecular mechanisms underlying toxin-induced neuronal stress remained to be unveiled. Here, we examined the toxicity ofC. difficiletoxin A against neuronal cells (SH-SY5Y). We found that toxin A treatment time- and dose-dependently decreased cell viability and triggered apoptosis accompanied by caspase-3 activation in this cell line. These effects were found to depend on the up-regulation of reactive oxygen species (ROS) and the subsequent activation of p38 MAPK and induction of p21Cip1/Waf1. Moreover, theN-acetyl-L-cysteine (NAC)-induced down-regulation of ROS could recover the viability loss and apoptosis of toxin A-treated neuronal cells. These results collectively suggest thatC. difficiletoxin A is toxic for neuronal cells, and that this is associated with rapid ROS generation and subsequent p38 MAPK activation and p21Cip1/Waf1up-regulation. Moreover, our data suggest that NAC could inhibit the toxicity ofC. difficiletoxin A toward enteric neurons.
authors.affiliation: Department of Life Science, College of Natural Science, Daejin University, Pocheon 11159, Republic of Korea.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Life Science, College of Natural Science, Daejin University, Pocheon 11159, Republic of Korea.
authors.forename: Ji
authors.initials: J
authors.lastname: Hong
authors.affiliation: Department of Life Science, College of Natural Science, Daejin University, Pocheon 11159, Republic of Korea.
authors.forename: I Na
authors.initials: IN
authors.lastname: Yoon
authors.affiliation: Lee Gil Ya Cancer and Diabetes Institute, Gachon University Graduate School of Medicine, Incheon 21936, Republic of Korea.
authors.forename: Jin Ku
authors.initials: JK
authors.lastname: Kang
authors.affiliation: Department of Agricultural Biology, National Academy of Agricultural Science, RDA, Wanju 55365, Republic of Korea.
authors.forename: Jae Sam
authors.initials: JS
authors.lastname: Hwang
authors.affiliation: Department of Life Science, College of Natural Science, Daejin University, Pocheon 11159, Republic of Korea.
authors.forename: Ho
authors.initials: H
authors.lastname: Kim
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001427:Bacterial Toxins / Q000494:pharmacology*; D053148:Caspase 3 / Q000096:biosynthesis; D045744:Cell Line, Tumor; D003092:Colitis / Q000382:microbiology / Q000503:physiopathology; D003106:Colon / Q000276:immunology / Q000382:microbiology / Q000503:physiopathology; D015536:Down-Regulation; D004768:Enterotoxins / Q000494:pharmacology*; D006168:Guinea Pigs; D007249:Inflammation; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D017382:Reactive Oxygen Species; C041348:tcdA protein, Clostridium difficile; D048051:p38 Mitogen-Activated Protein Kinases; D053148:Caspase 3; D020741:rho GTP-Binding Proteins; D000111:Acetylcysteine
keywords: Clostridium difficile; apoptosis; enteric nerve dysfunction; gut inflammation; neuronal cells (SH-SY5Y); toxin A