ABSTRACT
Severe muscle injury is hard to heal and always results in a poor prognosis. Recent studies found that extracellular vesicle-based therapy has promising prospects for regeneration medicine, however, whether extracellular vesicles have therapeutic effects on severe muscle injury is still unknown. Herein, we extracted apoptotic extracellular vesicles derived from mesenchymal stem cells (MSCs-ApoEVs) to treat cardiotoxin induced tibialis anterior (TA) injury and found that MSCs-ApoEVs promoted muscles regeneration and increased the proportion of multinucleated cells. Besides that, we also found that apoptosis was synchronized during myoblasts fusion and MSCs-ApoEVs promoted the apoptosis ratio as well as the fusion index of myoblasts. Furthermore, we revealed that MSCs-ApoEVs increased the relative level of creatine during myoblasts fusion, which was released via activated Pannexin 1 channel. Moreover, we also found that activated Pannexin 1 channel was highly expressed on the membrane of myoblasts-derived ApoEVs (Myo-ApoEVs) instead of apoptotic myoblasts, and creatine was the pivotal metabolite involved in myoblasts fusion. Collectively, our findings firstly revealed that MSCs-ApoEVs can promote muscle regeneration and elucidated that the new function of ApoEVs as passing inter-cell messages through releasing metabolites from activated Pannexin 1 channel, which will provide new evidence for extracellular vesicles-based therapy as well as improving the understanding of new functions of extracellular vesicles.
Subject(s)
Creatine/metabolism , Extracellular Vesicles , Muscle, Skeletal/metabolism , Myoblasts/metabolism , Regeneration , Connexins/metabolismABSTRACT
In modern medicine, bone and dental loss and defects are common and widespread morbidities, for which regenerative therapy has shown great promise. Mesenchymal stem cells, obtained from various sources and playing an essential role in organ development and postnatal repair, have exhibited enormous potential for regenerating bone and dental tissue. Currently, mesenchymal stem cells (MSCs)-based bone and dental regeneration mainly includes two strategies: the rescue or mobilization of endogenous MSCs and the application of exogenous MSCs in cytotherapy or tissue engineering. Nevertheless, the efficacy of MSC-based regeneration is not always fulfilled, especially in diseased microenvironments. Specifically, the diseased microenvironment not only impairs the regenerative potential of resident MSCs but also controls the therapeutic efficacy of exogenous MSCs, both as donors and recipients. Accordingly, approaches targeting a diseased microenvironment have been established, including improving the diseased niche to restore endogenous MSCs, enhancing MSC resistance to a diseased microenvironment and renormalizing the microenvironment to guarantee MSC-mediated therapies. Moreover, the application of extracellular vesicles (EVs) as cell-free therapy has emerged as a promising therapeutic strategy. In this review, we summarize current knowledge regarding the tactics of MSC-based bone and dental regeneration and the decisive role of the microenvironment, emphasizing the therapeutic potential of microenvironment-targeting strategies in bone and dental regenerative medicine.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate whether vitamin C can promote the proliferation ability of bone marrow mesenchymal stem cells (BMMSCs) derived from aging mice.</p><p><b>METHODS</b>The senescence-accelerated mouse prone 6 (SAMP6) mice and senescence-accelerated mouse resistant 1 (SAMR1) mice were used as the test group and the control group, respectively, and the SAMP6 mice were examined by micro-CT to verify the senescent phenotype. BMMSCs were harvested from the two mouse lines and cultured in vitro, and the cells from SAMP6 mice were subjected to treatment with different concentrations of vitamin C. The proliferation ability of the cells from the two mouse lines was tested using MTT assay and growth curves, and TeloTAGGG Telomerase PCR ELISA was used to measure the telomerase activity; PCR and Western blotting were performed to detect the expression level of telomerase reverse transcriptase (TERT) in the cells.</p><p><b>RESULTS</b>The SAMP6 mice displayed a bone senescent phenotype. The proliferation ability of BMMSCs derived from SAMP6 mice and their telomerase activity were significantly lower than those derived from SAMR1 mice (P<0.05). Vitamin C treatment significantly enhanced the proliferation ability of BMMSCs derived from SAMP6 mice in a dose-dependent manner (P<0.05) and increased telomerase activity and TERT expression in the cells (P<0.05). At the concentration of 100 µg/mL, vitamin C produced the strongest effect in promoting the proliferation of BMMSCs from SAMP6 mice, while at the concentration of 1000 µg/ml, growth suppression occurred in the cells.</p><p><b>CONCLUSION</b>Vitamin C can promote the proliferation of BMMSCs from aging mice possibly by increasing the cellular telomerase activity.</p>