Influence of TRAIL Deficiency on Th17 Cells and Colonic Microbiota in Experimental Colitis Mouse Model.

BACKGROUND: The abnormalities of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) are implicated in various autoimmune disorders and tumors. This study investigated the influence of TRAIL deficiency on Th17 cells and colonic microbiota in experimental colitis mouse model. METHODS: Mice were randomly divided into 4 groups: wild-type, TRAIL gene knock-out (TRAIL-/-), wild-type colitis and TRAIL-/- colitis groups. Colitis was induced by oral administration of 3.5% dextran sulfate sodium (DSS) for 7 consecutive days. Mice were given scores for disease severity both clinically and histopathologically. Th17 cells in peripheral blood and mesenteric lymph nodes (MLNs) were assessed using flow cytometry. The expression levels of Th17 cell markers IL-17A and ROR-γt were evaluated by quantitative real-time polymerase chain reaction. The colonic samples were also analyzed for microbiota profile by 16s-rDNA gene sequencing on variable V4 region. RESULTS: Compared with wild-type counterparts, TRAIL-/- mice developed more severe colitis after DSS treatment. Colitis TRAIL-/- mice had increased proportion of Th17 cells and elevated mRNA expression levels of IL-17A and ROR-γt in peripheral blood and MLNs compared with colitis wild-type mice. In contrast to colitis wild-type mice, the composition of colonic microbiota was shifted in colitis TRAIL-/- mice, and was characterized by increased alpha diversity, increased TM7, deferribacteres and tenericutes, and decreased proteobacteria at the phylum level. CONCLUSIONS: These findings suggested that TRAIL deficiency not only aggravated DSS-induced colitis, but also led to enhanced Th17 cell response and altered colonic microbiota composition.

Association of Crohn's Disease with Aryl Hydrocarbon Receptor Gene Polymorphisms in Patients from Southeast China.

Aims The aryl hydrocarbon receptor (AhR) plays a pivotal role in regulating the innate and the acquired immune systems. The present study aimed to investigate the association of Crohn's disease (CD) with AhR polymorphisms in a cohort of patients from Southeast China. Methods An improved multiple ligase detection reaction technique was applied to examine the polymorphisms of rs2158041, rs2066853, and rs10249788 in 310 patients with CD and 573 controls. Results Compared to the controls, the variant allele (T) and genotype (CT+TT) of rs2158041 were less frequent in patients with CD (both p < 0.05). Similar conclusions were drawn from patients with ileal CD and with stricture CD as compared to the controls (all p < 0.0083). However, no significant differences were observed in allele and genotype frequencies of rs2066853 and rs10249788 between patients with CD and the controls (all p > 0.05). Although rs2158041 and rs10249788 were in complete linkage disequilibrium with rs2066853, respectively, only the frequency of haplotype (TG) formed by rs2158041 and rs2066853 was significantly lower in patients with CD than that in the controls (p < 0.05). Conclusions AhR (rs2158041) might be a susceptible locus for CD, especially for the two subtypes: ileal CD and stricture CD.

Association of Ulcerative Colitis with FOXP3 Gene Polymorphisms and Its Colonic Expression in Chinese Patients.

Abnormalities of forkhead box P3 (FOXP3) are implicated in various autoimmune diseases. This study is aimed at investigating the association of ulcerative colitis (UC) with FOXP3 polymorphisms and its colonic expression in Chinese patients. Polymorphisms of rs3761548, rs2232365, rs2294021, and rs3761547 were examined in 472 UC patients and 525 healthy controls using the SNaPshot method. The colonic expression of FOXP3 mRNA and protein was assayed in inflammatory mucosa of 34 UC patients and normal mucosa of 36 patients with benign sigmoid polyps (normal controls) using real-time quantitative polymerase chain reaction and immunohistochemical analysis. All data were handled separately for females and males. As a result, the carrier frequencies with at least one variant allele of rs3761548, rs2232365, and rs229402 increased in female and male UC patients compared with healthy controls. Significant differences in these carrier frequencies were also observed between patients with mild and moderate UC and patients with severe UC. The expression of FOXP3 was higher in UC patients (both males and females), especially those with severe UC, than in normal controls. The expression of FOXP3 was downregulated in UC patients having at least one variant allele compared with UC patients having no variant allele of rs3761548, rs2232365, and rs2294021. Male gender (ß = -0.341), rs2294021 variation (ß = -0.503), and severe UC (ß = 0.361) were independently related to the mRNA expression of FOXP3 in UC patients. Together, our findings indicated that FOXP3 (rs3761548, rs2232365, and rs2294021) variations increased the risk of UC and were associated with the lower colonic expression of FOXP3 in UC patients.