The factors present in regenerating muscles impact bone marrow-derived mesenchymal stromal/stem cell fusion with myoblasts

Abstract

BackgroundSatellite cells, a population of unipotent stem cells attached to muscle fibers, determine the excellent regenerative capability of injured skeletal muscles. Myogenic potential is also exhibited by other cell populations, which exist in the skeletal muscles or come from other niches. Mesenchymal stromal/stem cells inhabiting the bone marrow do not spontaneously differentiate into muscle cells, but there is some evidence that they are capable to follow the myogenic program and/or fuse with myoblasts.MethodsIn the present study we analyzed whether IGF-1, IL-4, IL-6, and SDF-1 could impact human and porcine bone marrow-derived mesenchymal stromal/stem cells (hBM-MSCs and pBM-MSCs) and induce expression of myogenic regulatory factors, skeletal muscle-specific structural, and adhesion proteins. Moreover, we investigated whether these factors could induce both types of BM-MSCs to fuse with myoblasts. IGF-1, IL-4, IL-6, and SDF-1 were selected on the basis of their role in embryonic myogenesis as well as skeletal muscle regeneration.ResultsWe found that hBM-MSCs and pBM-MSCs cultured in vitro in the presence of IGF-1, IL-4, IL-6, or SDF-1 did not upregulate myogenic regulatory factors. Consequently, we confirmed the lack of their naïve myogenic potential. However, we noticed that IL-4 and IL-6 impacted proliferation and IL-4, IL-6, and SDF-1 improved migration of hBM-MSCs. IL-4 treatment resulted in the significant increase in the level of mRNA encoding CD9, NCAM, VCAM, and m-cadherin, i.e., proteins engaged in cell fusion during myotube formation. Additionally, the CD9 expression level was also driven by IGF-1 treatment. Furthermore, the pre-treatment of hBM-MSCs either with IGF-1, IL-4, or SDF-1 and treatment of pBM-MSCs either with IGF-1 or IL-4 increased the efficacy of hybrid myotube formation between these cells and C2C12 myoblasts.ConclusionsTo conclude, our study revealed that treatment with IGF-1, IL-4, IL-6, or SDF-1 affects BM-MSC interaction with myoblasts; however, it does not directly promote myogenic differentiation of these cells.

IL-4 and SDF-1 Increase Adipose Tissue-Derived Stromal Cell Ability to Improve Rat Skeletal Muscle Regeneration

“…The migration ability of these cells was improved by both IL-4 and SDF-1, but none of these factors increased the ADSCs' potential to fuse with mouse C2C12 myoblasts. It was previously shown that MSCs from bone marrow and Wharton's jelly are able to interact with myoblasts and form hybrid myotubes and that SDF-1 or IL-4 improve this process [50,51,55,68]. We also showed that human cells, e.g., those isolated from connective tissue of umbilical cord or bone marrow-derived mesenchymal cells, can form hybrid myotubes with mouse myoblasts [51,68].…”

“…It was previously shown that MSCs from bone marrow and Wharton's jelly are able to interact with myoblasts and form hybrid myotubes and that SDF-1 or IL-4 improve this process [50,51,55,68]. We also showed that human cells, e.g., those isolated from connective tissue of umbilical cord or bone marrow-derived mesenchymal cells, can form hybrid myotubes with mouse myoblasts [51,68]. Interestingly, SDF-1 which was shown by us to increase CD9 expression in mouse MSCs [50,58], did not have such an impact on rat ADSCs.…”

Hypoxic Preconditioned Bone Marrow-Derived Mesenchymal Stromal/Stem Cells Enhance Myoblast Fusion and Skeletal Muscle Regeneration

“…As we mentioned above, bone marrow-derived MSCs do not present naïve myogenic potential (45). These cells do not fuse in the absence of myoblasts and rarely fuse with myoblasts in co-cultures (45,(50)(51)(52)(53). However, bone marrow-derived MSCs could follow myogenic differentiation as the result of reprogramming induced by 5-azacytidine treatment, overexpression of Notch intracellular domain (NICD), paired box transcription factor 3 (Pax3), or constitutively active β-catenin, or as a result of 3D co-culture with myofibers (54)(55)(56)(57)(58)(59).…”

The Role of MSCs and Cell Fusion in Tissue Regeneration

“…MSCs do not possess myogenic differentiation capacity, but they are able to fuse to myoblasts to a small extent [54]. Differentiation capacity can be induced by the overexpression of Pax3 or β-catenin and by the satellite cell niche, but not by the niche's factors IGF-1, IL-4, IL-6 or SDF-1 [55][56][57][58]. Additionally, MSCs showed a positive effect on muscle regeneration in Duchenne muscular dystrophy model mice by secreting the chemokine CXCL12 and osteopontin [59].…”