Figure 2.

RNA molecules carried by mesenchymal stem cell-derived exosomes participate in the regulation of microglia.

(A) MSC-Exos contain and deliver important RNAs (including mRNAs, miRNAs, lncRNAs, circRNAs, snRNAs) and membrane and cytoplasmic protein components to effector cells in more than three ways: a) Exosomal membrane proteins can bind to target cell membrane proteins; b) Exosomal membrane proteins can be sheared in the extracellular matrix, and the fragments can act as ligands to bind to receptors; c) Exosome membranes can fuse directly with target cell membranes, releasing the contents. (B) Exosomes from different sources of MSCs play a role in regulating the microglial phenotype. Arg1: Arginase1; CH25H: cholesterol 25-hydroxylase; circRNA: circular RNA; Exos: exosomes; IRF: interferon regulatory factor; lncRNA: long noncoding RNA; miRNA: microRNA; mRNA: messenger RNA; MSCs: mesenchymal stem cells; NF-κB: nuclear factor kappa-B; snRNA: small nuclear RNA; TLR: Toll-like receptor.