Proinflammatory Bone Marrow Mesenchymal Stem Cell-Derived Exosomal miR-150-3p Suppresses Proinflammatory Polarization of Alveolar Macrophages in Sepsis by Targeting Inhibin Subunit Beta A.

Bone marrow mesenchymal stem cell (BMSC)-derived exosomes can protect lung tissues against sepsis, but its related mechanism remains elusive. BMSCs were primed with or without lipopolysaccharide (LPS) before extracting exosomes. The isolated exosomes were identified by transmission electron microscopy, nanoparticle tracking analysis, and western blot. LPS-stimulated macrophages were cocultured with exosomes for 24 h, followed by enzyme-linked immunosorbent assay, flow cytometry, and molecular experiments. Bioinformatics and luciferase assay were employed to investigate the interaction between miR-150-3p and inhibin subunit beta A (INHBA). MiR-150-3p expression was increased in exosomes in a proinflammatory environment. Exosomes suppressed proinflammatory polarization by downregulating IL-6, IL-1β, iNOS, and CD86, as well as promoted anti-inflammatory polarization by upregulating IL-10, ARG-1, and CD206 in LPS-stimulated macrophages. Such effects were more pronounced by LPS-primed exosomes, which was reversed in the absence of miR-150-3p. MiR-150-3p targeted INHBA. INHBA silencing decreased CD86 expression and increased CD206 expression in macrophages, but these effects were reversed by exosomal miR-150-3p inhibition. Proinflammatory BMSC-derived exosomal miR-150-3p suppressed proinflammatory polarization and promoted anti-inflammatory polarization of alveolar macrophages to attenuate LPS-induced sepsis by targeting INHBA.