Author(s): Harmit S. Ranhotra
. Systemic homeostasis in animals is maintained by a network of complex signalling pathways involving several kinds of endogenous molecules/metabolites. Over the years, the role of microbiota present in the digestive tract in animal physiology has been under focus and path-breaking findings have been reported. It seems that the gut microbiota has an influence in perhaps almost all the physiological functions, including the central nervous system in animals. The means by which the microbiota impinges control on the host system biology is manifold and complex. However, one of the mechanisms involve microbiota-derived metabolites that functions as ligands to modulate host tissue gene expression via the nuclear receptors (NRs), which is a novel way of exerting control over the host physiology. Few of the host NRs, such as the pregnane X receptor (PXR), farnesoid X receptor (FXR) and peroxisomeproliferator activated receptors (PPARs) gene transcriptional activities have been demonstrated to be modulated by the binding of microbial-secreted metabolites acting as ligands. Such interactions control vital functions in the host such as intestinal epithelial barrier protection, immune tolerance and anti-inflammatory responses. In this article, recent important findings in understanding gut microbiota-derived metabolites and select host NRs signalling will be briefly reviewed.