An enriched circulating extracellular vesicle microRNA, miR-451a, attenuates the RORγt expression in T cells in secondary lymphoid tissues, thereby ameliorating IL-17A-mediated allergic responses

The miRNAs contained in extracellular vesicles play a vital role in intercellular communication, and miR-451a, which is particularly enriched in circulating extracellular vesicles, contributes to various physiological events, including immune responses. We investigated the impact of miR-451a on IL-17-producing cell-dependent allergic responses using a DNFB-mediated delayed-type hypersensitivity (DTH) induction mouse model. In miR-451a knockout (KO) mice, an increase in IL-17-producing cells was observed in the ear and its associated mandibular lymph nodes following DNFB sensitization. Furthermore, we performed transcriptome analysis using RNA-seq on the mandibular lymph nodes of mice subjected to DNFB sensitization and challenge, evaluating changes and differences in gene expression. This study provides a new mechanism by which miR-451a controls the number and characteristics of IL-17-producing cells, shedding light on new mechanisms in allergies and immune responses.