Changes in intestinal microbiota and correlation with TLRs in ulcerative colitis in the coastal area of northern China

Abstract

Objective: To investigate the communities of fecal microbiota and the role of Toll-like receptors in patients with ulcerative colitis in the coastal area of northern China.

Methods: Stool samples from 31 patients with ulcerative colitis and 12 healthy individuals were collected. The total bacterial genomic DNA was extracted, and the V3+V4 hypervariable region in the bacterial 16S rRNA gene sequence was amplified by polymerase chain reaction (PCR). High-throughput sequencing analysis was performed on the Illumina Hiseq platform. The expression of TLR2, TLR4, Tollip, PPAR-γ, IL-6, and TNF-α in the colonic mucosa was measured by Western blots.

Results: The diversity of the fecal microbiota in patients with ulcerative colitis was significantly less than that in healthy control individuals (p < 0.05). The proportion of Bacteroidetes was significantly reduced (p < 0.01), whereas Proteobacteria was prevalent (p < 0.01) in patients with ulcerative colitis. At the genus level, the relative abundance of Streptococcus and Anaerostipes was significantly increased (p < 0.05), whereas the proportion of Bacteroides, Lachnospira, Ruminococcus, Phascolarctobacterium, and Coprococcus was significantly decreased in patients with ulcerative colitis (p < 0.05). The diversity indexes of fecal microbiota in patients with ulcerative colitis were negatively correlated with disease severity (p < 0.05). The relative abundance of Enterobacteriaceae was positively correlated with disease severity, and the relative abundance of Phascolarctobacterium, Anaerostipes, Fusobacterium, Parabacteroides, Oscillospira, and Ochrobactrum were negatively correlated with disease severity. The expression levels of TLR2 and TLR4 in the intestinal mucosa were positively correlated with the relative abundance of Streptococcus and Enterobacteriaceae, respectively (r = 0.481, p = 0.007; r = 0.455, p = 0.017).

Conclusion: There were significant changes in the diversity and composition of the fecal microbiota in patients with ulcerative colitis compared to healthy individuals. The dysbiosis of gut microbiota and correlation with TLRs might play important roles in the pathogenesis and progression of ulcerative colitis.

Keywords: 16S rRNA; Gut microbiota; High-throughput sequencing; Toll-like receptors; Ulcerative colitis.