Transcriptional profile of GTP-mediated differentiation of C2C12 skeletal muscle cells

Abstract

Several purine receptors have been localised on skeletal muscle membranes. Previous data support the hypothesis that extracellular guanosine 5′-triphosphate (GTP) is an important regulatory factor in the development and function of muscle tissue. We have previously described specific extracellular binding sites for GTP on the plasma membrane of mouse skeletal muscle (C2C12) cells. Extracellular GTP induces an increase in intracellular Ca 2+ concentrations that results in membrane hyperpolarisation through Ca 2+ -activated K + channels, as has been demonstrated by patch-clamp experiments. This GTPevoked increase in intracellular Ca 2+ is due to release of Ca 2+ from intracellular inositol-1,4,5-trisphosphate-sensitive stores. This enhances the expression of the myosin heavy chain in these C2C12 myoblasts and commits them to fuse into multinucleated myotubes, probably via a phosphoinositide-3-kinase-dependent signal-transduction mechanism. To define the signalling of extracellular GTP as an enhancer or modulator of myogenesis, we investigated whether the gene-expression profile of differentiated C2C12 cells (4 and 24 h in culture) is affected by extracellular GTP. To investigate the nuclear activity and target genes modulated by GTP, transcriptional profile analysis and realtime PCR were used. We demonstrate that in the early stages of differentiation, GTP up-regulates genes involved in different pathways associated with myogenic processes, including cytoskeleton structure, the respiratory chain, myogenesis, chromatin reorganisation, cell adhesion, and the Jak/Stat pathway, and down-regulates the mitogenactivated protein kinase pathway. GTP also increases the expression of three genes involved in myogenesis, Pp3ca, Gsk3b, and Pax7. Our data suggests that in the myogenic C2C12 cell line, extracellular GTP acts as a differentiative factor in the induction and sustaining of myogenesis.

JAK-STAT pathway and myogenic differentiation

“…These findings provided the basis for further understanding of the role of the JAK-STAT pathway in myogenic differentiation. In addition, among transcriptional profile of GTP (guanosine 5′-triphosphate)-mediated differentiation of C2C12 myoblasts, genes such as interleukin 6, Pim-1 and IL1Ra (interleukin 1 receptor antagonist homolog 1) are upregulated, and it is suggested that JAK-STAT pathway can play a crucial role in myogenic differentiation 43 . In next section, we will focus on the role of the JAK-STAT pathway in the differentiation and proliferation of skeletal muscle myoblasts.…”

Guanosine-Based Nucleotides, the Sons of a Lesser God in the Purinergic Signal Scenario of Excitable Tissues

“…More recently, it has been shown that in the early stages of differentiation, GTP regulates many genes specifically involved in myogenesis including Pp3ca, Gsk3b and Pax7. This indicates a possible function for the nucleotide as a differentiation regulator in these cells [48].…”

The effect of palmitate supplementation on gene expression profile in proliferating myoblasts

“…2 ). Calcium homeostasis appeared to be important in the maintenance of mechanisms promoting the expression of muscle-specific proteins and myoblast fusion (Mancinelli et al 2012 ). Another pathway enriched by differentially expressed genes in palmitate-treated myoblasts is Wnt signaling, which is important for early development and commitment of myogenic cells (Otto et al 2008 ).…”