title: Recombinant Clostridium difficile toxin B induces endoplasmic reticulum stress in mouse colonal carcinoma cells.
abstract: Clostridium difficile is the main cause of antibiotic-associated diarrhea and pseudomembranous colitis in humans and animals. Its pathogenicity is primarily linked to the secretion of two exotoxins (TcdA and TcdB). Although great progress in the toxic mechanism of TcdA and TcdB has been achieved, there are many conflicting reports about the apoptotic mechanism. More importantly, apoptotic endoplasmic reticulum (ER) stress has been reported in cells treated with Shiga toxins-another kind of cytotoxins that can cause diarrhea and colitis. Herein we checked whether TcdB can induce ER stress. The results showed that recombinant TcdB (rTcdB) activated molecular markers of unfolded protein response, suggesting that rTcdB induced ER stress in CT26 cells. However, rTcdB did not induce the up-regulation of C/EBP homologous protein (CHOP), a classic mediator of apoptotic ER stress, but it activated the precursor of cysteine aspartic acid-specific protease 12 (caspase-12), a controversial mediator of apoptotic ER stress. Besides, glucosyltransferase activity-deficient mutant recombinant TcdB induced ER stress, though it has no cytotoxic or cytopathic effect on CT26 cells. Altogether, these data demonstrated that ER stress induced by rTcdB is glucosyltransferase-independent, indicating that ER stress induced by rTcdB is non-apoptotic. This work also offers us a new insight into the molecular mechanism of CHOP protein expression regulation and the role of CHOP expression in ER stress.
authors.affiliation: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China.
authors.forename: Chunli
authors.initials: C
authors.lastname: Sun
authors.affiliation: School of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510006, China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China.
authors.forename: Shuyi
authors.initials: S
authors.lastname: Chen
authors.affiliation: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China.
authors.forename: Zhendong
authors.initials: Z
authors.lastname: Li
authors.affiliation: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China School of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510006, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Li
authors.affiliation: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China jufwang@scut.edu.cn.
authors.forename: Jufang
authors.initials: J
authors.lastname: Wang
mesh_terms: D051701:Activating Transcription Factor 4 / Q000235:genetics; D051702:Activating Transcription Factor 6 / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001426:Bacterial Proteins / Q000235:genetics / Q000633:toxicity*; D001427:Bacterial Toxins / Q000235:genetics / Q000633:toxicity*; D053454:Caspase 12 / Q000378:metabolism; D045744:Cell Line, Tumor; D016360:Clostridioides difficile / Q000235:genetics / Q000472:pathogenicity; D003106:Colon / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects* / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D016695:Glycosyltransferases / Q000378:metabolism; D006801:Humans; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000633:toxicity; D015398:Signal Transduction; D051742:Transcription Factor CHOP / Q000235:genetics / Q000378:metabolism; D056811:Unfolded Protein Response / Q000187:drug effects / Q000235:genetics; D019892:eIF-2 Kinase / Q000235:genetics
chemical_list: D051701:Activating Transcription Factor 4; D051702:Activating Transcription Factor 6; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D053454:Caspase 12; D016695:Glycosyltransferases; D012333:RNA, Messenger; D011994:Recombinant Proteins; D051742:Transcription Factor CHOP; D019892:eIF-2 Kinase; C081452:Atf4 protein, mouse; C497112:Atf6 protein, mouse; C497250:Ddit3 protein, mouse; C031815:toxB protein, Clostridium difficile; C506440:Casp12 protein, mouse
keywords: Clostridium difficile; apoptosis; endoplasmic reticulum stress; unfolded protein response