EXPLORING THE TRANSCRIPTION PROGRAM OF INTESTINAL GOBLET CELL RESPONSE AND MUCIN PRODUCTION IN TRICHURIS MURIS INFECTION

Abstract

Goblet cells in the mucosal layer of the gastrointestinal tract are the primary source of gel-forming mucins, representing front-line defense. Sterile alpha motif-pointed domain ETS family transcription factor (SPDEF) has a crucial role in terminal differentiation, proliferation and maturation of goblet cells. Gut microbiota is an integral part of our internal environment. In a murine model of intestinal helminthic infection Trichuris muris, the interaction between host microbiota and parasite was seen to play critical roles in immune defense. This interaction is mediated through various mechanisms, including Toll-like receptor (TLR) and nucleotide-binding oligomerization domain (NOD)-like receptor signaling cascades. However, the precise role of intestinal microbiota and NOD/TLR signaling in regulating SPDEF is not yet understood. Hence, we investigated the role of SPDEF in intestinal goblet cell response, the role of helminth-microbiota axis and NOD/TLR signaling in modulating SPDEF during T. muris infection. Experiments were conducted in wild-type (SPDEF+/+) and SPDEF-deficient (SPDEF-/-) mice on BALB/c background at different timepoints of T. muris infection. We observed increased PAS+ goblet cells and higher expression of SPDEF and Muc2 in SPDEF+/+ mice following infection with elevated levels of IL-4 and IL-13. SPDEF+/+ mice showed decreased worm burden from day 14 to 21 post-infection. Microbial analysis revealed altered composition in SPDEF+/+ and SPDEF-/- after infection. Microbiota was transplanted from naïve and T. muris infected mice to separate groups of antibiotic-treated (ABX-treated) mice. Increased PAS+ goblet cells and higher expression of SPDEF and Muc2 were observed in ABX-treated mice after receiving naive and T. muris-altered microbiota. Goblet cell number, the expression of SPDEF and Muc2 were higher in ABX-treated mice who received T. muris-altered microbiota. Microbial analysis revealed differences in T. muris-altered microbiota compared to naïve microbiota. In vitro experiment was conducted in human colonic mucin secreting LS174T cells where we observed stimulated mRNA expression of SPDEF and MUC2 by T. muris excretory-secretory products. These findings reveal new information about major interactions among parasites, microbiota and SPDEF-mediated intestinal goblet cell response in the context of host defense.