TLR5 Signaling in the Regulation of Intestinal Mucosal Immunity

Abstract

Toll-like receptor 5 (TLR5) is a pattern recognition receptor that specifically recognizes flagellin and consequently plays a crucial role in the control of intestinal homeostasis by activating innate and adaptive immune responses. TLR5 overexpression, on the other hand, might disrupt the intestinal mucosal barrier, which serves as the first line of defense against harmful microbes. The intestine symbiotic bacteria, mucous layer, intestinal epithelial cells (IECs), adherens junctions (such as tight junctions and peripheral membrane proteins), the intestinal mucosal immune system, and cytokines make up the intestinal mucosal barrier. Impaired barrier function has been linked to intestinal illnesses such as inflammatory bowel disease (IBD). IBD is a persistent non-specific inflammatory illness of the digestive system with an unknown cause. It is now thought to be linked to infection, environment, genes, immune system, and the gut microbiota. The significance of immunological dysfunction in IBD has received more attention in recent years. The purpose of this paper is to explore TLR5’s position in the intestinal mucosal barrier and its relevance to IBD.

Mucosal TLR5 activation controls healthspan and longevity

“…Another study indicates that even in the absence of the TLR5 gene, environmental factors can significantly influence the gut microbiome profile, thereby affecting metabolic syndrome outcomes 23 . Furthermore, the application of TLR5 agonists has been shown to stimulate hepatocyte proliferation 33 , further illustrating the multifaceted roles of TLR5 in metabolic regulation and immune system modulation 35 . These findings highlight the unique and diversified roles of TLR5, setting it apart from its proinflammatory counterparts and underscoring its potential in age-modulation interventions.…”

Toll‐like receptors in health and disease

“…For example, the capsid proteins of the virus that causes respiratory infections and the pneumococcal virulent proteins are recognized by TLR4 17,18 . TLR5 is capable of identifying the continuous structural domain of flagellin 19 . It is strongly expressed in DCs of the lamina propria of the small intestine, where it detects flagellin from flagellated bacteria, inducing the production of inflammatory factors and thereby modulating innate and adaptive responses to intestinal bacteria (Figure 1).…”

Nanomaterials modulate tumor-associated macrophages for the treatment of digestive system tumors

“…TLR5, a pattern recognition receptor, exhibits a specific affinity for flagellin [ 239 ]. Within the hepatic context, TLR5 elicits inflammatory reactions via NF-κB signaling cascades [ 240 , 241 ].…”