Myostatin inhibits cell proliferation and protein synthesis in C₂C₁₂ muscle cells

Abstract

Myostatin mutations in mice and cattle are associated with increased muscularity, suggesting that myostatin is a negative regulator of skeletal muscle mass. To test the hypothesis that myostatin inhibits muscle cell growth, we examined the effects of recombinant myostatin in mouse skeletal muscle C2C12 cells. After verification of the expression of cDNA constructs in a cell-free system and in transfected Chinese hamster ovary cells, the human recombinant protein was expressed as the full-length (375-amino acid) myostatin in Drosophila cells (Mst375D), or the 110-amino acid carboxy-terminal protein in Escherichia coli(Mst110EC). These proteins were identified by immunoblotting and were purified. Both Mst375D and Mst110EC dose dependently inhibited cell proliferation (cell count and Formazan assay), DNA synthesis ([3H]thymidine incorporation), and protein synthesis ([1-14C]leucine incorporation) in C2C12 cells. The inhibitory effects of both proteins were greater in myotubes than in myoblasts. Neither protein had any significant effects on protein degradation or apoptosis. In conclusion, recombinant myostatin proteins inhibit cell proliferation, DNA synthesis, and protein synthesis in C2C12muscle cells, suggesting that myostatin may control muscle mass by inhibiting muscle growth or regeneration.

Characterization of GHRs, IGFs and MSTNs, and analysis of their expression relationships in blunt snout bream, Megalobrama amblycephala

“…Nevertheless, some studies into the relationship between GH and MSTNs might further elucidate this complex relationship. An inverse relationship between GH and MSTN was found in rat muscle (Kirk et al, 2000) and human muscle cells (Taylor et al, 2001). Some researchers also found that a GH-responsive element was identified to be the upstream of the MSTN promoter region in fish (Roberts and Goetz, 2003;Taylor et al, 2001), which suggested that at the same time GH could regulate MSTN gene transcription and stimulate the GHR gene expression.…”

“…However, in previous studies, a negative relationship between GHR and MSTN mRNA levels in healthy adult men had been reported (Marcell et al, 2001). Theoretically, MSTNs was thought to be in a negative relationship with GHRs, due to the inhibition of muscle growth (McPherron et al, 1997) and cell proliferation (Taylor et al, 2001). While GHRs, which were the receptors of GH, they may participate in stimulation on muscle protein synthesis.…”

“…In teleosts, a GHresponsive element was identified from upstream of the MSTN promoter region in salmonid fish (Roberts and Goetz, 2003;Taylor et al, 2001), which suggested that at the same time GH could down-regulate MSTN gene transcription and stimulate IGF-I gene expression. However, a glucocorticoid-or cortisol-induced up and/or down regulation of MSTN gene expression would cause a different result (Vianello et al, 2003;Weber et al, 2005), and it was verified in different species (Biga and Meyer, 2009).…”

Molecular mechanism of size control in development and human diseases

“…This suggests that myostatin normally inhibits both muscle cell growth and cell division. Further studies demonstrate that myostatin inhibits cell division by inducing Cdk inhibitor p21 and inhibits cell growth by reducing protein synthesis [159,160]. Therefore, myostatin may function as a growth coordinator that coordinately regulates cell division and cell size.…”

Approaching a New Age in Duchenne Muscular Dystrophy Treatment

“…63,64 De-repression of quiescent muscle progenitor cells is a possible mechanism for enhanced muscle regeneration in the absence of myostatin for which there is accumulating evidence. [65][66][67][68][69] In addition, the direct modulation of myostatin fibroblast proliferation likely contributes to the observed effects on fibrosis. 70,71 Myostatin can be inhibited postnatally by a variety of mechanisms that similarly induce muscle growth.…”