microRNAs in nutritional signaling and metabolic syndrome

Altered gene expression caused by unhealthy diets is a major instigator of metabolic disease. Metabolic syndrome, including non-alcoholic fatty liver disease (NAFLD), cardiovascular diseases and type II diabetes (T2D), displays strongly and consistently abnormal microRNA (miRNA) profiles that are associated with nutrient-surplus and other pathological conditions. miRNAs are a class of short non-coding RNAs that typically suppress messenger RNA (mRNA) translation by promoting mRNA degradation and/or inhibiting translation although the dogma of miRNAs acting exclusively as gene suppressors is challenged by instances of miRNAs upregulating gene expression. Additionally, the significance of food-borne miRNAs in human health has also drawn the attention scientists with reports showing that exosomes serve as transporters to transfer nutritionally derived miRNAs into human subjects. This chapter will overview the cross-talk between dietary-derived miRNAs and host gene expression and their potential impact on human health. The chapter further highlights that aberrant expression of certain miRNAs may contribute to the pathogenesis of metabolic diseases.