Olamide Ogungbola

Conference 2023 Live Talk

Talk title

Intestinal interferon-lambda receptor 1 expression and responses are significantly decreased in pediatric IBD patients

Authors and Affiliations

Olamide Ogungbola1, Ramsha Mahmood1,2, Kaelie Bittorf3, Suellen Lamb3, Wael El-Matary4, Eytan Wine5, D. Lorne J. Tyrrell3, Heather Armstrong1,2, Deanna M. Santer1

1. Department of Immunology, University of Manitoba, Winnipeg, MB
2. Department of Internal Medicine, University of Manitoba, Winnipeg, MB
3. Li Ka Shing Institute of Virology and Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB
4. Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB 5 Center of Excellence for Gastrointestinal Inflammation and Immunity Research and Department of Pediatrics, University of Alberta, Edmonton, AB4 Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB 5 Center of Excellence for Gastrointestinal Inflammation and Immunity Research and Department of Pediatrics, University of Alberta, Edmonton, AB

Abstract

Background

Inflammatory bowel diseases (IBD) affect approximately 300,000 Canadians, negatively impacting the quality of life, with incidence rates in children especially rising. The immune proteins, type III Interferons (Interferon lambda, IFN-λs), were shown to be critical for mucosal healing and dampening inflammation in gut-damaged mouse models, but IFN-λ activity in human patients with IBD is understudied. We hypothesized children with severe IBD would present with lower intestinal IFN-λR levels and responses contributing to IBD pathology by aggravating inflammation, decreasing mucosal healing, and impairing barrier function.

Methods

We screened 14 novel antibodies through flow cytometry to find the optimal clone that binds IFN-λ receptor subunit (IFN-λR1) protein in human intestinal tissue and IFN-λR1 levels were quantified by immunohistochemistry in biopsy samples from children without IBD, Crohn’s disease, or ulcerative colitis (n=9 each). Fresh patient biopsies were also cultured ex vivo for 24hr in media +/- IFN-λ3 and gene expression was quantified by RT-qPCR. Tests used are one-way Anova with Tukey’s test for 3 groups and unpaired t-test with Mann-Whitney test for 2 groups.

Results

We identified 2 antibodies (mAb 8 and 13) that accurately stained human cell lines and immune cells known to express IFN-λR1 protein (gut epithelial cells and B cells). We found through immunohistochemistry that IFN-λR1 expression is significantly reduced in gut epithelial and immune cells within pediatric IBD intestinal tissue, even at non-inflamed sites (p<0.01, 30-50% reduction) and this was even more pronounced when comparing moderate/severe disease compared to children with no disease activity. This led to lower IFN-λ induction of known IFN-λ-dependent genes such as IFI44 and MX1 in IBD compared to non-IBD biopsies (p<0.05, 4-7 fold reduction) measured through RT-qPCR.

Conclusions

Together, our findings support our hypothesis that children with IBD have dysregulated IFN-λ receptor responses which could lead to the lower induction of key anti-inflammatory pathways. This work supports the strategy to restore and promote IFN-λ responses as a therapy for pediatric IBD.