PMID- 29383879 OWN - NLM STAT- MEDLINE DCOM- 20191028 LR - 20211204 IS - 1582-4934 (Electronic) IS - 1582-1838 (Print) IS - 1582-1838 (Linking) VI - 22 IP - 4 DP - 2018 Apr TI - Clostridium difficile toxin B induces autophagic cell death in colonocytes. PG - 2469-2477 LID - 10.1111/jcmm.13555 [doi] AB - Toxin B (TcdB) is a major pathogenic factor of Clostridum difficile. However, the mechanism by which TcdB exerts its cytotoxic action in host cells is still not completely known. Herein, we report for the first time that TcdB induced autophagic cell death in cultured human colonocytes. The induction of autophagy was demonstrated by the increased levels of LC3-II, formation of LC3(+) autophagosomes, accumulation of acidic vesicular organelles and reduced levels of the autophagic substrate p62/SQSTM1. TcdB-induced autophagy was also accompanied by the repression of phosphoinositide 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) complex 1 activity. Functionally, pharmacological inhibition of autophagy by wortmannin or chloroquine or knockdown of autophagy-related genes Beclin 1, Atg5 and Atg7 attenuated TcdB-induced cell death in colonocytes. Genetic ablation of Atg5, a gene required for autophagosome formation, also mitigated the cytotoxic effect of TcdB. In conclusion, our study demonstrated that autophagy serves as a pro-death mechanism mediating the cytotoxic action of TcdB in colonocytes. This discovery suggested that blockade of autophagy might be a novel therapeutic strategy for C. difficile infection. CI - (c) 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine. FAU - Chan, Hung AU - Chan H AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Zhao, Shan AU - Zhao S AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Zhang, Lin AU - Zhang L AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Ho, Jeffery AU - Ho J AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Leung, Czarina C H AU - Leung CCH AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Wong, Wai T AU - Wong WT AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Tian, Yuanyuan AU - Tian Y AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Liu, Xiaodong AU - Liu X AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Kwong, Thomas N Y AU - Kwong TNY AD - Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Hong Kong, Hong Kong. AD - State Key Laboratory of Digestive Disease, LKS Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Chan, Raphael C Y AU - Chan RCY AD - Department of Microbiology, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Yu, Sidney S B AU - Yu SSB AD - School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Wang, Maggie H T AU - Wang MHT AD - The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Tse, Gary AU - Tse G AD - Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Wong, Sunny H AU - Wong SH AD - Department of Medicine & Therapeutics, The Chinese University of Hong Kong, Hong Kong, Hong Kong. AD - State Key Laboratory of Digestive Disease, LKS Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Chan, Matthew T V AU - Chan MTV AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. FAU - Wu, William K K AU - Wu WKK AUID- ORCID: 0000-0002-5662-5240 AD - Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong. AD - State Key Laboratory of Digestive Disease, LKS Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20180131 PL - England TA - J Cell Mol Med JT - Journal of cellular and molecular medicine JID - 101083777 RN - 0 (Autophagy-Related Protein 5) RN - 0 (Bacterial Proteins) RN - 0 (Bacterial Toxins) RN - 0 (Beclin-1) RN - 0 (SQSTM1 protein, human) RN - 0 (Sequestosome-1 Protein) RN - 0 (toxB protein, Clostridium difficile) RN - EC 2.7.1.1 (MTOR protein, human) RN - EC 2.7.11.1 (TOR Serine-Threonine Kinases) RN - EC 6.2.1.45 (Autophagy-Related Protein 7) SB - IM MH - Apoptosis/drug effects MH - Autophagosomes/drug effects/metabolism/microbiology MH - Autophagy/*genetics MH - Autophagy-Related Protein 5 MH - Autophagy-Related Protein 7 MH - Bacterial Proteins/*genetics/metabolism MH - Bacterial Toxins/*genetics/metabolism MH - Beclin-1/genetics MH - Clostridioides difficile/*genetics/pathogenicity MH - Clostridium Infections/genetics/microbiology/*therapy MH - Colon/cytology/microbiology MH - Humans MH - Phosphatidylinositol 3-Kinases/genetics MH - Phosphorylation MH - Sequestosome-1 Protein/genetics MH - TOR Serine-Threonine Kinases/genetics PMC - PMC5867081 OTO - NOTNLM OT - autophagy OT - mechanistic target of rapamycin OT - mouse embryonic fibroblast OT - toxin B EDAT- 2018/02/01 06:00 MHDA- 2019/10/29 06:00 PMCR- 2018/04/01 CRDT- 2018/02/01 06:00 PHST- 2017/05/10 00:00 [received] PHST- 2018/01/01 00:00 [accepted] PHST- 2018/02/01 06:00 [pubmed] PHST- 2019/10/29 06:00 [medline] PHST- 2018/02/01 06:00 [entrez] PHST- 2018/04/01 00:00 [pmc-release] AID - JCMM13555 [pii] AID - 10.1111/jcmm.13555 [doi] PST - ppublish SO - J Cell Mol Med. 2018 Apr;22(4):2469-2477. doi: 10.1111/jcmm.13555. Epub 2018 Jan 31.