Induction of Skeletal Muscle Progenitors and Stem Cells from human induced Pluripotent Stem Cells

Induced pluripotent stem cells (iPSCs) have the potential to differentiate into various types of cells and tissues including skeletal muscle. The approach to convert these stem cells into skeletal muscle cells offers hope for patients afflicted with skeletal muscle diseases such as Duchenne muscular dystrophy (DMD). Several methods have been reported to induce myogenic differentiation with iPSCs derived from myogenic patients. An important point for generating skeletal muscle cells from iPSCs is to understand in vivo myogenic induction in development and regeneration. Current protocols of myogenic induction utilize techniques with overexpression of myogenic transcription factors such as Myod1(MyoD), Pax3, Pax7, and others, using recombinant proteins or small molecules to induce mesodermal cells followed by myogenic progenitors, and adult muscle stem cells. This review summarizes the current approaches used for myogenic induction and highlights recent improvements.

The effect of extracellular matrix on myogenic induction of adipose mesenchymal stem cells

Bankground: As one of the hot cells in the field of regenerative medicine, adipose mesenchymal stem cells(ADSCs) have been proved to have the ability of myoblast differentiation, but the disadvantage is that the efficiency of myoblast differentiation is not very high.Extracellular matrix(ECM), as a mixture of cytokines and proteins secreted by cells, is the substance secreted by cells. It has the advantages of non-toxic and harmless, and can provide the necessary material and environmental basis for cell growth and development.This study was to explore whether the myogenic differentiation potential of ADSCs cultured in ECM was improved.Method: ADSCs were extracted from subcutaneous fat of male SD rats at the age of 3 months and weight 250g. The third generation cellular of ADSCs were prepared for ECM，and the ECM was contained in the culture bottle for amplify the ADSCs. Myogenic induction was performed by 5-azacytidine using the same generation of ADSCs cultured with ECM and non-ECM.Result: ECM can significantly increase the rate of cell proliferation (P<0.05).Immunofluorescence detected the expression of β-actin, Myod and Desmin in cells ,and showed no significant difference in the expression of β-actin between groups (P>0.05). However, there were significant differences in Myod and Desmin between groups (P<0.001).RT-PCR showed that the mRNA expressions of myosin heavy chain(MHC), troponin, Myogein and Myf5 were significantly different among groups (P<0.001).Conclusion: ECM culture of ADSCs can improve its growth rate and myogenic differentiation potential.

Resveratrol reverses myogenic induction supression caused by high glucose through activating SIRT1/AKT/FOXO1 pathway

Background: Long-term high glucose environment can cause muscle tissue atrophy, and then lead to musculoskeletal depression or even disability. Regenerative medicine is an extremely attractive select to solve this problem. Resveratrol is a compound which has various clinical therapeutic effects including regulating the myogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). So, the objective of this study is to observe if resveratrol affect myogenic induction of rat BMSCs under high glucose environment and explore the possible mechanism. Methods: Rat BMSCs were isolated and cultured. The phenotypes were identified when cultured to the third passage cells (P3 cells). Then the P3 cells were used to induce to differentiate into myogenic cells by using the conditioned medium. After grouping, glucose, resveratrol and EX527 (inhibitor of SIRT1) were added. The cell viability was measured by MTT assay. The myogenesis related protein was detected by immunofluorescence. The level of reactive oxygen species (ROS) and superoxide dismutase (SOD) activity were detected by use of assay kits. The cell cycle was assayed with flow cytometry. The expression of FOXO1, AKT, p-AKT, MyoD1 and Myogenin were measured by WB. All above indicators in different groups were quantified and compared. Results: During myogenic induction, after 72h treatment, high glucose (35 mmol/L) reduced cell viability and proliferation of rat BMSCs significantly, increased intracellular ROS levels clearly, decreased SOD activity obviously, and restrained AKT/FOXO1 pathway apparently. Resveratrol (15μmol/L) could regulate the process positively and reverse the suppression caused by high glucose partly through restoring cell proliferation and viability, reducing peroxidative damage and activating AKT/FOXO1 pathway. After pretreated the cells with EX527 (20 μmol/L), this reverse effect of resveratrol was eliminated. Conclusion: Resveratrol not only promoted myogenic induction of rat BMSCs, but also partially reversed myogenic induction supression of rat BMSCs caused by high glucose through activating SIRT1/AKT/FOXO1 pathway. [Key words] resveratrol, bone marrow mesenchymal stem cells, myogenic induction, glucose, SIRT1, AKT, FOXO1

Spontaneous and specific myogenic differentiation of human mesenchymal stem cells on polyethylene glycol-linked multi-walled carbon nanotube films for skeletal muscle engineering

PEG-CNT films spontaneously direct the skeletal myogenic differentiation of hMSCs in the absence of myogenic induction factors.