A novel myogenic cell line with phenotypic properties of muscle progenitors

Pb inhibited C2C12 myoblast differentiation by regulating HDAC2

Myogenesis is a crucial process governing skeletal muscle development and homeostasis. Lead (Pb) exposure impaired the development and the health of bones, which slows the growth of children. However, it is far from clear what exactly the effects of Pb on skeletal muscle development are. In this study, C2C12 cells are commonly used as an in vitro model of muscle regeneration due to their ability to transition from a proliferative phase into differentiated myofibers. The dose of 1, 5, and 10 μM Pb were adopted to study the toxicity of Pb on C2C12 proliferation and differentiation. First, the effects of Pb on cell viability were detected and the results demonstrated that 5 μM and 10 μM Pb exposure decreased cell viability, while 1 μM Pb exposure has no obvious effects on cell viability. Then, 1-10 μM Pb exposure seriously reduced the C2C12 myoblasts differentiation, with the decrease of myogenic differentiation marker genes expression, including Muscle creatine kinase (MCK), Myosin Heavy Chain 4 (MYH4), Myogenin (MYOG), Myogenic Differentiation (MYOD). What's more, it was found that the epigenetic modifier histone deacetylase-2 (HDAC2) was upregulated after Pb exposure on C2C12 myoblasts. Further studies conclusively showed knockdown of HDAC2 ameliorated Pb-damaged C2C12 myoblasts differentiation, indicating HDAC2 plays a vital role in the Pb-induced C2C12 myoblasts differentiation deficits. In summary, these results demonstrated that Pb exposure inhibited C2C12 myoblasts differentiation by regulating HDAC2.

In vitro expression profiling of myostatin, follistatin, decorin and muscle-specific transcription factors in adult caprine contractile myotubes

Skeletal muscle is one of the several adult postmitotic tissues that retain the capacity to regenerate, which relies on a population of quiescent precursors, termed satellite cells. Proliferation and differentiation of myoblasts to form mature myotubes in vitro has been a valuable tool in the characterization of the cellular events during myogenesis, which is a multistep process starting with progenitor cell proliferation, followed by their exit from the cell cycle, differentiation, alignment, and fusion to form multinucleated myotubes. A typical feature during muscle differentiation is the variation in expression of various genes along with myogenic factors. In this experiment, mRNA level of myostatin, follistatin, decorin and three muscle-specific transcription factors in adult caprine contractile myotubes have been studied through quantitative real time PCR. We observed that the expression level of myostatin, decorin, Myf5 and myogenin transcripts were significantly higher in contractile myotubes compared to myoblast monolayer (P < 0.05), and follistatin level was similar in both types of cells, whereas MyoD transcript level was significantly high in monolayer culture which might be due heterogeneity of myoblast population. It is concluded that the information generated would provide the base line information as well as monitoring markers to undertake experiments aimed at modulating muscle growth.