BMSC-Derived Exosomes Intervened the Pathogenic Changes of Scleroderma in Mouse Through Its microRNAs

Abstract

BackgroundSystemic sclerosis (SSc) is a disease with severe fibrosis of the skin without effective therapy. While bone marrow mesenchymal stem cell (BMSC) derived exosome was a potential stem cell-based candidate in treatment of SSc.MethodsBMSCs were isolated from the bone marrow of mouse and identified with the surface markers and multi-lineage differentiation. The exosomes were isolated from the BMSCs culture medium with ultracentrifugation and identified with NTA, TEM and western blot. The miRNAs of the BMSC-derived exosomes (BMSC-EXOs) were studied via miRNA sequencing and bioinformatic analysis. The SSc model was established in mice by bleomycin (BLM) subcutaneous injection and the mice were treated with BMSCs or BMSC-derived exosomes. The skin tissues were dissociated and analyzed with H&E staining, RNA sequencing and immunohistochemical staining.ResultsEvident pathological changes like fibrosis and inflammation induced in the skin of BLM-treated mice. Both BMSCs and BMSC-EXOs effectively intervened such pathological manifestations and disease process, in a very similar way. The effects of the BMSC-EXOs were tracked to their microRNAs, which were proved to be involved in regulating the proliferation and differentiation of multiple cell types and in multiple biological processes when the EXOs functioned. Furthermore, the TGF-β1 positive cells and α-SMA positive myofibroblasts were significantly increased in the scleroderma skin of BLM-treated mice, but evidently reduced in the EXO-treated SSc group. Meanwhile, the number of mast cells as well as the infiltrated macrophages and lymphocytes were evidently increased in the skins of the BLM-treated mice, but significantly reduced by the EXO treatment. Such observations were confirmed by the data of the detected inflammatory cytokines that significantly higher mRNA levels of Il6, Il10 and Tnf-α were found in SSc mice, but reduced following the EXO treatment. Through bioinformatics analysis, TGFβ and WNT signaling pathways were revealed to be closely involved in the pathogenic changes in mouse SSc and could be the main targets for treating the disease.ConclusionsBMSC-derived exosomes could be developed as a potential therapy for treating the dysfunction of the skin in SSc, especially for its similar efficacy with BMSCs but less regulated as compared to cell therapy. Its mechanisms are involved in its microRNAs which alleviate the SSc pathogenic changes through regulating WNT and TGFβ signaling pathways.