BMAL1 regulates tubular epithelial-derived exosomal miR-27a-3p to inhibits macrophage-myofibroblast transition thus alleviating ischemia/reperfusion induced renal fibrosis

We confirmed that exosome-mediated MMT directly aggravated renal fibrosis and that this process was directly regulated by BMAL1 through in vivo and in vitro exosome uptake experiments and Rab27a knockout mouse construction. High-throughput miRNA sequencing of exosomes derived from TCMK-1 cells and ChIP assays were used to confirm that exosomal miR-27a-3p was downregulated after hypoxia-reoxygenation (H/R) treatment and that BMAL1 directly promoted the transcription of miR-27a-3p.

We identified TGFBR1 as the target gene of miR-27a-3p by transfecting cells with miR-27a-3p mimics and miR-27a-3p inhibitors and performing dual luciferase assays. Finally, we transfected cells with si-TGFBR1 and identified the TGFBR1/smad3 pathway as a key pathway for regulating MMT and renal fibrosis regulated by tubular epithelium-derived exosomal miR-27a-3p. Our findings indicated that BMAL1 was suppressed in renal IRI, which promoted MMT and renal fibrosis by upregulating the level of miR-27a-3p in tubular epithelial-derived exosomes.