Plakoglobin and High-Mobility Group Box 1 Mediate Intestinal Epithelial Cell Apoptosis Induced by Clostridioides difficile TcdB.

Journal Article (Journal Article)

Clostridioides difficile infection (CDI) is the leading cause of antibiotic-associated intestinal disease, resulting in severe diarrhea and fatal pseudomembranous colitis. TcdB, one of the essential virulence factors secreted by this bacterium, induces host cell apoptosis through a poorly understood mechanism. Here, we performed an RNA interference (RNAi) screen customized to Caco-2 cells, a cell line model of the intestinal epithelium, to discover host factors involved in TcdB-induced apoptosis. We identified plakoglobin, also known as junction plakoglobin (JUP) or γ-catenin, a member of the catenin family, as a novel host factor and a previously known cell death-related chromatin factor, high-mobility group box 1 (HMGB1). Disruption of those host factors by RNAi and CRISPR resulted in resistance of cells to TcdB-mediated and mitochondrion-dependent apoptosis. JUP was redistributed from adherens junctions to the mitochondria and colocalized with the antiapoptotic factor Bcl-XL . JUP proteins could permeabilize the mitochondrial membrane, resulting in the release of cytochrome c . Our results reveal a novel role of JUP in targeting the mitochondria to promote the mitochondrial apoptotic pathway. Treatment with glycyrrhizin, an HMGB1 inhibitor, resulted in significantly increased resistance to TcdB-induced epithelial damage in cultured cells and a mouse ligated colon loop model. These findings demonstrate the critical roles of JUP and HMGB1 in TcdB-induced epithelial cell apoptosis. IMPORTANCE Clostridioides difficile infection (CDI) is the leading cause of hospital-acquired diarrhea. Toxins, especially TcdB, cause epithelial cell apoptosis, but the underlying cell death mechanism is less clear. Through an apoptosis-focused RNAi screen using a bacterium-made small interfering (siRNA) library customized to a human colonic epithelial cell model, we found a novel host factor, plakoglobin (γ-catenin), as a key factor required for cell apoptosis induced by TcdB. Plakoglobin targets and permeabilizes mitochondria after stimulation by TcdB, demonstrating a hitherto underappreciated role of this catenin family member in the apoptosis of intestinal epithelial cells. We also found a previously known cell death-related chromatin factor, HMGB1, and explored the inhibition of HMGB1 for CDI therapy in vivo .

Full Text

Duke Authors

Cited Authors

  • Li, Y; Xu, W; Ren, Y; Cheung, H-C; Huang, P; Kaur, G; Kuo, C-J; McDonough, SP; Fubini, SL; Lipkin, SM; Deng, X; Chang, Y-F; Huang, L

Published Date

  • October 2022

Published In

Volume / Issue

  • 13 / 5

Start / End Page

  • e0184922 -

PubMed ID

  • 36043787

Pubmed Central ID

  • PMC9600731

Electronic International Standard Serial Number (EISSN)

  • 2150-7511

International Standard Serial Number (ISSN)

  • 2150-7511

Digital Object Identifier (DOI)

  • 10.1128/mbio.01849-22


  • eng