Full-length gasdermin-B (GSDMB) regulates epithelial adhesion and migration, and is increased in patients with IBD

Abstract Resolution of inflammation at mucosal surfaces is a process critical for patients with IBD. GWAS revealed variant SNPs within the gene encoding gasdermin-B (GSDMB) that associates with an increased susceptibility to IBD and elevated GSDMB expression. The aim of this study was to determine the expression pattern and function significance of GSDMB in the pathogenesis of IBD. Primary intestinal biopsy and isolated intestinal epithelial specimens from IBD patients and non-IBD controls were evaluated for mRNA and protein expression. Using the human intestinal epithelial cell line, HT-29, CRISPR-cas9 knockout cells lacking GSDMB were generated, and used for in vitro XTT, cell-death and cell migration assays. Additionally, human epithelial cells transfected with GSDMB constructs and/or stimulated with methotrexate (MTX) were employed for relevant functional assays. We report for the first time a dramatic increase in full-length epithelial-specific GSDMB in IBD patients compared to healthy controls, which unlike other gasdermin family members, does not partake in program-mediated cell death. Additionally, we describe a functional decrease in in vitro proliferative activity, wound repair and an increase in focal adhesion proteins in epithelial cells lacking GSDMB, phenotypically rescued via transfection or MTX treatment. Importantly, GSDMB expression is decreased in IBD patients in remission, to that of levels of non-IBD controls. Taken together, our data suggests that increased epithelial-derived GSDMB during IBD is protective in function and promotes epithelial-specific adhesion and migration, providing rationale for the potential therapeutic use of GSDMB to optimize gut mucosal healing and restoration to homeostasis.