Expression of Toll-Like Receptors 2, 4 and 5 in Relation to Gut Microbiota in Colon Neoplasm Patients with and without Inflammatory Bowel Disease

Toll-Like Receptors (TLRs) are the critical mediators of inflammatory routs in the gut, which play an essential role in regulating the immune responses towards various ligands derived from pathogenic bacteria. Also, TLR signaling has been implicated in the development of Inflammatory Bowel Disease (IBD), Adenomatous Polyp (AP), and Colorectal Cancer (CRC). Here, we aimed to examine the expression of some TLRs concerning certain fecal bacteria in AP and CRC patients with and without IBD.

This case-control study collected fecal and colonic tissue samples from 93 patients versus Normal Controls (NC) via colonoscopy. Fecal samples were used for DNA extraction, and the abundance of selected fecal bacteria was determined by absolute real-time PCR. Also, the gene expression of TLR2, 4, and 5 was analyzed using RT-PCR on the colonic tissues of participants.

Compared to NC individuals, in AP and CRC patients, the mRNA expressions of TLR4 and TLR2 were significantly increased while TLR5 was decreased. A meaningful association between TLRs mRNA expression levels and the abundance of some selected fecal bacteria was detected. Also, there was a significant relationship between participant’s food regimes, smoking habit and intestinal TLRs expression.

Our study proposed the important role of TLRs during adenomatous and CRC formation. Alterations in TLRs expression associated with certain gut bacteria may contribute to disease development.