Chaohui Dai
Yangzhou University, China
Title: Regulation and molecular mechanism of TLR5 on resistance to E. coli F18 in weaned piglets
Biography
Biography: Chaohui Dai
Abstract
Toll-like receptor 5 (TLR5) plays an important role in the immune system. In this study, we performed transcriptome sequencing of the duodenum in E. coli F18-resistant and -sensitive Sutai weaned piglets and analyzed the differential expression of TLR5. The cellular localization of TLR5 was investigated, the small intestinal epithelial cell line (IPEC-J2) with TLR5 gene overexpression and interference was established. Following stimulation of IPEC-J2 cells by E. coli, we evaluated the effect of TLR5 expression on E. coli invasion. The results showed that TLR5 expression level in the duodenum and jejunum was significantly higher in sensitive than in resistant piglets. IPEC-J2 cell lines with TLR5 interference and overexpression were established, and the expression of genes associated with the TLR5 signaling pathway were significantly higher in TLR5-overexpressed cells than in control cells. Bacterial adhesion was higher in TLR5-overexpressed cells than in blank cells and lower in TLR5 interference than in blank cells. The core promoter region of TLR5 included two CpG islands and 15 acting elements. The methylation of the mC-6 site in the second CpG island of the promoter region had a regulatory effect on TLR5 expression. Therefore, low expression of TLR5 inhibited the immune response to some extent and decreased cell damage, which was conducive to the resistance to E. coli infection. The methylation of the mC-6 CG site in the second CpG island of the TLR5 promoter inhibited the binding of the transcription factor Sp1, which decreased TLR5 expression and affected E. coli resistance.