Fig. 3. The mechanism by which mesenchymal stem cells-derived exosomes (MSCs-Exos) regulate the immune response. Bone marrow stem cell (BMSC)-Exos can regulate the TLR4/MyD88/NF-κB signaling pathway to produce the production of anti-inflammatory factors. MSCs-Exos with miR-181c and miR-23b can inhibit the formation of microglia via the Phosphatase and Tensin homolog (PTEN) signaling pathway and inhibit the TLR4/NF-κB pathway to inhibit the production of proinflammatory factors. Epidural fat (EF)-MSCs-Exos and human Wharton’s jelly (HWJ)-MSCs-Exos can inhibit the NLRP3 activation to inhibit the production of proinflammatory factors. MSCs-Exos with miR-125a and miR-124-3p can inhibit M2 macrophage polarization by regulating the IRF5 and Ern1 signaling pathways. MSCs-Exos with miR-216a-5p can inhibit M2 macrophage polarization by inhibiting TLR4/NF-κB and activating the PI3K/Akt signaling pathway. MSCs-Exos can inhibit the NFκB p65 signaling pathway to reduce astrocyte toxicity. MSCs-Exos with miR-146a-5p can inhibit the Traf6/Irak1/NF-κB signaling pathway to reduce astrocyte toxicity.