Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease involving multiple systems. Immunopathology believes that abnormal T cell function and excessive production of autoantibodies by B cells are involved in multi-organ damage. Human umbilical cord mesenchymal stem cells (hUCMSCs) therapies have endowed with promise in SLE, while the function of MSC-derived extracellular vesicles (MSC-EVs) was still unclear. Extracellular vesicles (EVs) are subcellular components secreted by a paracellular mechanism and are essentially a group of nanoparticles. EVs play a vital role in cell-to-cell communication by acting as biological transporters. New evidence has shown beneficial effects of MSC-EVs on autoimmune diseases, such as their immunomodulatory properties. In this study, we investigated whether hUCMSCs derived extracellular vesicles (hUCMSC-EVs) could regulate abnormal immune responses of T cells or B cells in SLE. We isolated splenic mononuclear cells from MRL/lpr mice, a classical animal model of SLE. PBS (Phosphate-buffered saline), 2 × 105 hUCMSCs, 25 µg/ml hUCMSC-EVs, 50 µg/ml hUCMSC-EVs were co-cultured with 2 × 106 activated splenic mononuclear cells for 3 days in vitro, respectively. The proportions of CD4+ T cell subsets, B cells and the concentrations of cytokines were detected. Both hUCMSCs and hUCMSC-EVs inhibited CD4+ T cells, increased the production of T helper (Th)17 cells, promoted the production of interleukin (IL)-17 and transforming growth factor beta1 (TGF-β1) (P < 0.05), although they had no significant effects on Th1, Th2, T follicular helper (Tfh), regulatory T (Treg) cells and IL-10 (P > 0.05); only hUCMSCs inhibited CD19+ B cells, promoted the production of interferon-gamma (IFN-γ) and IL-4 (P < 0.05). hUCMSCs exert immunoregulatory effects on SLE at least partially through hUCMSC-EVs in vitro, therefore, hUCMSC-EVs play novel and potential regulator roles in SLE.