The molecular mechanisms underlying gut microbiota-miRNA interaction in metabolic disorders

Metabolic disorders are a major global health problem. Gut microbiota not only affect host metabolism through metabolites, inflammatory processes, and microbial-derived extracellular vesicles, but they also modulate the host microRNA, which may impact the host metabolism. Hence, the underlying mechanisms between gut microbiota-microRNA interaction can potentially be a novel alternative strategy for treating metabolic disorders. This review aims to give an update on the latest evidence and current knowledge of the underlying mechanisms of gut microbiota-miRNA interaction, focusing on metabolic homeostasis. Gut microbiota mainly communicate with host microRNA through lipopolysaccharide and secondary microbial metabolites. These signalling messengers circulate around the metabolic organs and modify gene expression through microRNA interference. Interestingly, while intestinal microRNAs play a vital role in both intestinal barrier and gut microbiota homeostasis, the presence of gut microbiota is also required for the proper functioning of intestinal microRNAs, suggesting a cooperative mechanism in intestinal health. Although the correlations between gut microbiota and microRNA have been observed in both mice and humans, a causal relationship should be confirmed. Moreover, further investigation is needed to provide more evidence of a gut microbiota-microRNA interaction to support the possibility of using that axis as a novel therapeutic target to treat metabolic disorders.