Vitamin D3and carbamazepine protect againstClostridioides difficileinfection in mice by restoring macrophage lysosome acidification

作者：Hung Chan, Qing Li, Xiansong Wang, Wing Yingzhi Liu, Wei Hu, Judeng Zeng, Chuan Xie, Thomas Ngai Yeung Kwong, Idy Hiu Ting Ho, Xiaodong Liu, Huarong Chen, Jun Yu, Ho Ko, Raphael Chiu Yeung Chan, Margaret Ip, Tony Gin, Alfred S.L. Cheng, Lin Zhang, Matthew T.V. Chan, Sunny H. Wong, William Ka Kei Wu · 发表于：Autophagy · 年份：2022 · DOI：10.1080/15548627.2021.2016004 · 被引用次数：38 · 研究领域：Clostridium difficile and Clostridium perfringens research

Clostridioides difficile infection (CDI) is a common cause of nosocomial diarrhea. TcdB is a major C. difficile exotoxin that activates macrophages to promote inflammation and epithelial damage. Lysosome impairment is a known trigger for inflammation. Herein, we hypothesize that TcdB could impair macrophage lysosomal function to mediate inflammation during CDI. Effects of TcdB on lysosomal function and the downstream pro-inflammatory SQSTM1/p62-NFKB (nuclear factor kappa B) signaling were assessed in cultured macrophages and in a murine CDI model. Protective effects of two lysosome activators (i.e., vitamin D3 and carbamazepine) were assessed. Results showed that TcdB inhibited CTNNB1/β-catenin activity to downregulate MITF (melanocyte inducing transcription factor) and its direct target genes encoding components of lysosomal membrane vacuolar-type ATPase, thereby suppressing lysosome acidification in macrophages. The resulting lysosomal dysfunction then impaired autophagic flux and activated SQSTM1-NFKB signaling to drive the expression of IL1B/IL-1β (interleukin 1 beta), IL8 and CXCL2 (chemokine (C-X-C motif) ligand 2). Restoring MITF function by enforced MITF expression or restoring lysosome acidification with 1α,25-dihydroxyvitamin D3 or carbamazepine suppressed pro-inflammatory cytokine expression in vitro. In mice, gavage with TcdB-hyperproducing C. difficile or injection of TcdB into ligated colon segments caused prominent MITF downregulation in macrophages. Vitamin D3...