Regulation of Inflammatory Bowel Disorder Inflammation by ST8Sia6

• Published in: The Journal of immunology (1950) Vol. 206; no. 1_Supplement; pp. 60 - 60.15
• Main Authors: Crotts, Sydney B, Friedman, David J, Shapiro, Michael J, Rajcula, Matthew, Shapiro, Virginia Smith
• Format: Journal Article
• Language: English
• Published: 01.05.2021
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.206.Supp.60.15

Abstract Inflammatory bowel disorders (IBD), including Crohn’s disease and colitis, have a prevalence between 10–20%. IBD patients experience a reduced quality of life due to symptoms such as diarrhea, abdominal cramps, anal bleeding. The exact etiology of IBD is incompletely understood, but the immune response plays a critical role. Innate immune cells integrate the sum of stimulatory and inhibitory signals to determine overall activation. Solidifying the roles of pertinent proteins and their interactions is critical in mapping the immune response and understanding the implications of clinical treatment of IBD. ST8Sia6 is a sialic acid transferase which adds terminal a2,8 disialic acids to cell surface glycoproteins, and we have found that ST8Sia6 generates ligands for Siglec-2 and Siglec-E on innate immune cells, including colonic macrophages and neutrophils. These siglecs are inhibitory sialic acid-binding membrane receptors expressed on several immune cell subsets. Restraining ST8Sia6 should therefore enhance the immune response by reducing siglec-mediated inhibition. To examine this, our lab has generated a novel ST8Sia6 knockout (KO) mouse. At baseline these mice are healthy, but we have found that ST8Sia6 KO mice challenged with dextran sodium sulfate (DSS)-induced colitis lose weight and succumb to colonic inflammation significantly faster than their wildtype (WT) counterparts, particularly at low doses. ST8Sia6 KO mice exhibit increased histological damage and immune infiltration of the colon and small bowel as compared to WT controls. This data demonstrates a role for ST8Sia6 in regulating the hose immune response to inflammatory bowel disorders.