miR-21 regulates transcript levels in a gut symbiont.

In the gut, microRNAs (miRNAs) produced by intestinal epithelial cells are secreted into the lumen and can shape the composition and function of the gut microbiome. Crosstalk between gut microbes and the host plays a key role in irritable bowel syndrome (IBS) and inflammatory bowel diseases. Yet, little is known about how the miRNA-gut microbiome axis contributes to the pathogenesis of these conditions. In this study, we aimed to explore the ability of miR-21, a miRNA deregulated in IBD, to associate with and regulate gut microbiome function. We identify preferential miR-21 associating partners within the gut microbiota, and demonstrate that miR-21 can regulate transcript levels in the symbiont Bacteroides thetaiotaomicron. Sequencing was performed at the Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna under the project IDs JMF-2212-04 and JMF-2205-07.