Interactions between toll-like receptors signaling pathway and gut microbiota in host homeostasis

BackgroundToll-like receptors (TLRs) are a family of fundamental pattern recognition receptors in the innate immune system, constituting the first line of defense against endogenous and exogenous antigens. The gut microbiota, a collection of commensal microorganisms in the intestine, is a major source of exogenous antigens. The components and metabolites of the gut microbiota interact with specific TLRs to contribute to whole-body immune and metabolic homeostasis.ObjectiveThis review aims to summarize the interaction between the gut microbiota and TLR signaling pathways and to enumerate the role of microbiota dysbiosis-induced TLR signaling pathways in obesity, inflammatory bowel disease (IBD), and colorectal cancer (CRC).ResultsThrough the recognition of TLRs, the microbiota facilitates the development of both the innate and adaptive immune systems, while the immune system monitors dynamic changes in the commensal bacteria to maintain the balance of the host-microorganism symbiosis. Dysbiosis of the gut microbiota can induce a cascade of inflammatory and metabolic responses mediated by TLR signaling pathways, potentially resulting in various metabolic and inflammatory diseases.ConclusionUnderstanding the crosstalk between TLRs and the gut microbiota contributes to potential therapeutic applications in related diseases, offering new avenues for treatment strategies in conditions like obesity, IBD, and CRC. Recent studies have revealed that gut microbiota plays a vital role in host homeostasis and shows a close relationship with various metabolic diseases. The interactions between toll-like receptors (TLRs) and gut microbiota contribute to whole-body homeostasis in a complex manner. Dysbiosis of gut microbiota could induce a cascade of inflammatory responses mediated by TLR signaling pathways, which may result in metabolic and inflammatory diseases. We summarize the interaction between gut microbiota and TLR signaling pathways and then enumerate the role of microbiota dysbiosis-induced TLR signaling pathways in obesity and inflammatory bowel disease to better understand how the crosstalk between TLRs and gut microbiota contributes to potential therapeutic applications in related diseases.image