A20 Restores Impaired Intestinal Permeability and Inhibits Th2 Response in Mice with Colitis.

BACKGROUND/AIMS: The etiology of inflammatory bowel disease is multifactorial and still obscure. The protective role of ubiquitin E3 ligase A20 (A20) in colitis needs to be further elucidated. This study aimed to investigate whether A20 exogenous administration restored impaired intestinal permeability and inhibited T helper (Th)2 response in mice with colitis. METHODS: The effect of A20 overexpression in colonic mucosa on epithelial barrier function and T cell differentiation was evaluated in mice with dextran sulfate sodium (DSS)-induced chronic colitis. RESULTS: A20 rectal treatment alleviated DSS-induced chronic colitis and restored impaired intestinal permeability. Oral challenge with 2% DSS elicited a Th2-type response in mice with colitis, and A20 rectal treatment inhibited CD4+ interleukin (IL)-4+ T cell differentiation and proliferation. In addition, the RNA expressions of Th2-related costimulatory molecular T-cell immunoglobulin and mucin domain (TIM)-1 and IL-4 were suppressed, while thrombospondin (TSP)-1 and interferon (IFN)-γ expressions were upregulated, after A20 rectal administration. CONCLUSION: A20 rectal treatment restores impaired intestinal permeability and inhibits activated Th2 cell response in mice with colitis.