The IRE1α/XBP1 pathway sustains cytokine responses of group 3 innate lymphoid cells in inflammatory bowel disease
Siyan Cao, Jose L. Fachi, Kaiming Ma, Alina Ulezko Antonova, Qianli Wang, Zhangying Cai, Randal J. Kaufman, Matthew A. Ciorba, Parakkal Deepak, Marco Colonna
Siyan Cao, Jose L. Fachi, Kaiming Ma, Alina Ulezko Antonova, Qianli Wang, Zhangying Cai, Randal J. Kaufman, Matthew A. Ciorba, Parakkal Deepak, Marco Colonna
View: Text | PDF
Research Article Gastroenterology Immunology

The IRE1α/XBP1 pathway sustains cytokine responses of group 3 innate lymphoid cells in inflammatory bowel disease

Abstract

Group 3 innate lymphoid cells (ILC3s) are key players in intestinal homeostasis. ER stress is linked to inflammatory bowel disease (IBD). Here, we used cell culture, mouse models, and human specimens to determine whether ER stress in ILC3s affects IBD pathophysiology. We show that mouse intestinal ILC3s exhibited a 24-hour rhythmic expression pattern of the master ER stress response regulator inositol-requiring kinase 1α/X-box–binding protein 1 (IRE1α/XBP1). Proinflammatory cytokine IL-23 selectively stimulated IRE1α/XBP1 in mouse ILC3s through mitochondrial ROS (mtROS). IRE1α/XBP1 was activated in ILC3s from mice exposed to experimental colitis and in inflamed human IBD specimens. Mice with Ire1α deletion in ILC3s (Ire1αΔRorc) showed reduced expression of the ER stress response and cytokine genes including Il22 in ILC3s and were highly vulnerable to infections and colitis. Administration of IL-22 counteracted their colitis susceptibility. In human ILC3s, IRE1 inhibitors suppressed cytokine production, which was upregulated by an IRE1 activator. Moreover, the frequencies of intestinal XBP1s+ ILC3s in patients with Crohn’s disease before administration of ustekinumab, an anti-IL-12/IL-23 antibody, positively correlated with the response to treatment. We demonstrate that a noncanonical mtROS-IRE1α/XBP1 pathway augmented cytokine production by ILC3s and identify XBP1s+ ILC3s as a potential biomarker for predicting the response to anti–IL-23 therapies in IBD.

Authors

Siyan Cao, Jose L. Fachi, Kaiming Ma, Alina Ulezko Antonova, Qianli Wang, Zhangying Cai, Randal J. Kaufman, Matthew A. Ciorba, Parakkal Deepak, Marco Colonna

×

Figure 4

Ire1αΔRorc mice are highly susceptible to C. difficile infection.

Options: View larger image (or click on image) Download as PowerPoint
Ire1αΔRorc mice are highly susceptible to C. difficile infection. (A) I...
(A) Ire1αΔRorc and Ire1αfl/fl mice were orally infected by C. difficile (C. diff) following treatment with antibiotics. (B) Weight loss and (C) clinical scores were measured daily (n = 9–10). (D–F) Mice were sacrificed on day 5 after infection and colons harvested for measurement of length (D), as well as histology score and goblet cell numbers (E) based on H&E staining and alcian blue/PAS staining (F). Scale bar: 100 μm. (G) Colonic LP ILC3s were isolated on day 5 after infection and stimulated ex vivo with 10 ng/mL IL-23 and 10 ng/mL IL-1β for 4 hours (GolgiPlug for the last 3 hours); intracellular cytokine levels were measured by flow cytometry (n = 7–9). Representative plots are on the top, and the percentage of cytokine+ ILC3s in each are mouse shown on the bottom. (H) Representative plots and absolute number of neutrophils and inflammatory monocytes in the colonic LP of C. difficile–infected mice on day 2 after infection (n = 8–9). (I) Mice received FITC-dextran by gavage on day 3 after infection, and serum was collected 4 hours later and FITC-dextran quantitated (n = 5). (J) Bacterial translocation into the liver, spleen, and mLNs was assessed by qPCR on day 3 after infection (n = 5). (K) Expression of cytokines, mucins, and antimicrobial peptides in the proximal colon on day 5 after infection was measured by qPCR relative to β-actin (n = 7–9). Data represent at least 2 independent experiments, each involving 5–9 mice per group. Error bars indicate the SEM. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, by unpaired, 2-tailed Student’s t test.