Comprehensive Molecular Profiles of Functionally Effective Mesenchymal Stem/Stromal Cell-Derived Extracellular Vesicles in Immunomodulation

Abstract Accumulating evidence indicates that mesenchymal stem/stromal cell-derived extracellular vesicles (MSC-EVs) exhibit immunomodulatory effects by delivering therapeutic RNAs and proteins; however, the molecular mechanism underlying the EV-mediated immunomodulation is not fully understood. Here, we found that EVs from early-passage MSCs had better immunomodulatory potency than EVs from late-passage MSCs in TCR- or TLR4-stimulated splenocytes and in mice with ocular Sjogren’s syndrome. Moreover, MSC-EVs were more effective when produced from 3D culture of the cells than from the conventional 2D culture. Comparative molecular profiling using proteomics and microRNA sequencing revealed the enriched factors in MSC-EVs that were functionally effective in immunomodulation. Amongst them, manipulation of TGFβ1, PTX3, let-7b-5p or miR-21-5p levels in MSCs significantly affected the immunosuppressive effects of their EVs. Furthermore, there was a strong correlation between the expression levels of TGFβ1, PTX3, let-7b-5p or miR-21-5p in MSC-EVs and their suppressive function. Therefore, our comparative strategy identified TGFβ1, PTX3, let-7b-5p or miR-21-5p as key molecules mediating the therapeutic effects of MSC-EVs in autoimmune disease. These findings would help understand the molecular mechanism underlying EV-mediated immunomodulation and provide functional biomarkers of EVs for the development of robust EV-based therapies.