Fecal let-7b and miR-21 directly modulate the intestinal microbiota, driving chronic inflammation

New study led by Emilie Viennois and conducted by Maite Casador-Bedmar uncovers how specific fecal microRNAs, let-7b and miR-21, drive gut inflammation by altering microbiota composition. This study shows that let-7b and miR-21, found to be elevated in stool from patients and mouse models, can directly shape the gut microbiota and drive inflammation in IBD. These microRNAs were found to disrupt the balance of gut bacteria, increase proinflammatory r esponses, and weaken the intestinal barrier. Conversely, blocking these miRANs reduced inflammation and improved gut health, unveiling a new therapeutic target to fight IBD and restoring balance to the gut microbiome.