Microbial signals, MyD88, and lymphotoxin drive TNF-independent intestinal epithelial tissue damage
Iulia Rusu, … , Averil Ma, Michael G. Kattah
Iulia Rusu, … , Averil Ma, Michael G. Kattah
Published January 25, 2022
Citation Information: J Clin Invest. 2022;132(5):e154993. https://doi.org/10.1172/JCI154993.
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Research Article Gastroenterology Immunology

Microbial signals, MyD88, and lymphotoxin drive TNF-independent intestinal epithelial tissue damage

Abstract

Anti-TNF antibodies are effective for treating patients with inflammatory bowel disease (IBD), but many patients fail to respond to anti-TNF therapy, highlighting the importance of TNF-independent disease. We previously demonstrated that acute deletion of 2 IBD susceptibility genes, A20 (Tnfaip3) and Abin-1 (Tnip1), in intestinal epithelial cells (IECs) sensitized mice to both TNF-dependent and TNF-independent death. Here we show that TNF-independent IEC death after A20 and Abin-1 deletion was rescued by germ-free derivation or deletion of MyD88, while deletion of Trif provided only partial protection. Combined deletion of Ripk3 and Casp8, which inhibits both apoptotic and necroptotic death, completely protected against death after acute deletion of A20 and Abin-1 in IECs. A20- and Abin-1–deficient IECs were sensitized to TNF-independent, TNFR1-mediated death in response to lymphotoxin α (LTα) homotrimers. Blockade of LTα in vivo reduced weight loss and improved survival when combined with partial deletion of MyD88. Biopsies of inflamed colon mucosa from patients with IBD exhibited increased LTA and IL1B expression, including a subset of patients with active colitis on anti-TNF therapy. These data show that microbial signals, MyD88, and LTα all contribute to TNF-independent intestinal injury.

Authors

Iulia Rusu, Elvira Mennillo, Jared L. Bain, Zhongmei Li, Xiaofei Sun, Kimberly M. Ly, Yenny Y. Rosli, Mohammad Naser, Zunqiu Wang, Rommel Advincula, Philip Achacoso, Ling Shao, Bahram Razani, Ophir D. Klein, Alexander Marson, Jessie A. Turnbaugh, Peter J. Turnbaugh, Barbara A. Malynn, Averil Ma, Michael G. Kattah

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Figure 8

LTA and IL1B mRNA are increased in inflamed intestinal mucosa from patients with IBD and both TNF and LTα3 are cytotoxic to human colonoids.

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LTA and IL1B mRNA are increased in inflamed intestinal mucosa from pati...
(A) qPCR for the indicated mRNA transcripts in colonic mucosal biopsies of inflamed (red) or noninflamed (blue) areas from patients with IBD or without IBD (non-IBD, black). Biopsy samples were obtained at 1 or 2 locations and processed separately; each data point represents 1 patient (median and interquartile ranges, IL1B shown with log2 y axis to display full range). If the colon was entirely inflamed or noninflamed, values from the 2 sets of biopsies were averaged. If biopsies were obtained separately from inflamed and noninflamed colon, then they were processed and displayed separately. (B) qPCR for the indicated mRNA transcripts in colonic mucosal biopsies in the subset of patients from A on anti-TNF therapy at the time of biopsy (median and interquartile ranges, IL1B shown with log2 y axis to display full range). (C) Representative microscopy images of SYTOX dead cell nucleic acid stain (pseudocolor red). Scale bars: 100 μm. (D) Quantitative luminescent cell viability assay of human colonoids derived from non-IBD and IBD patients, treated with indicated stimuli for 48 hours (mean ± SEM; 50 ng/mL recombinant human LTα3 [hLTα3], 25 ng/mL hTNF). For panel A, significance was assessed using 1-way ANOVA with Tukey’s multiple-comparison test. For panel B, significance was assessed by unpaired Student’s t test. For panel D, significance was assessed using repeated measures 1-way ANOVA with Dunnett’s multiple-comparison test relative to vehicle.