HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Accepted manuscript (PDF) All Versions of this Article: JOE-08-0151v1 198/1/243    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Al-Shanti, N. Articles by Stewart, C. PubMed PubMed Citation Articles by Al-Shanti, N. Articles by Stewart, C.

N Al-Shanti, Manchester Metropolitan University, Institute of Biophysical and Clinical Research into Human Movement, Stoke On Trent, ST7 2HL, United Kingdom
C Stewart, Manchester Metropolitan University, Institute of Biophysical and Clinical Research into Human Movement, Stoke On Trent, United Kingdom

Correspondence: Nasser Al-Shanti, Email: n.al-shanti{at}mmu.ac.uk

Abstract

Cell differentiation is usually accompanied by irreversible cell cycle arrest which is critical for skeletal muscle differentiation. We therefore hypothesise that PD98059 MEK pathway blocker when administrated to C2 myoblasts will arrest cell cycle, and consequently enhance differentiation. This hypothesis was examined using C2 cells cultured for 48hr in differentiation media (untreated) or supplemented with either a single dose of 10ng/ml of IGF-I or 20microM of PD98059 for 48hr. Creatine kinase activity was increased 7.5-fold (P <0.05) in the presence of PD98059, whereas untreated and IGF-I treated cells induced 4.5 and 4-fold increase respectively when compared with controls and were not only associated with myotubes formation but also with cell cycle arrest in G1 (86 ±3.2%). Moreover, expression levels of MyoD and myogenin mRNAs were significantly higher in PD-treated cells (4.7± 0.15 and 314± 10.2 ng/reaction; respectively) than untreated (2.0± 0.2 and 233± 11 ng/reaction respectively) or IGF-treated cells (3.2 ±0.24 and 296± 16.2 ng/reaction respectively). Unexpectedly, Id3 mRNA, the potent negative regulator of muscle differentiation was also expressed at significantly higher levels in PD-treated cells (77± 0.346 ng/reaction) than untreated and IGF-I treated cells 49± 7.7 and 47± 0.7 ng/reaction respectively. Expressions of the muscle differentiation-specific genes (IGFBP-5, IGF-IIR and IGF-II) were also increased significantly in PD-treated cells when compared to untreated cells. Interestingly, a significant increased levels of p38 MAPK phosphorylation in cells treated with PD (49.0± 6.7%) when compared with DM-treated cells (31.7 ±5.7%). These findings uncover a previously unconsidered positive effect of PD98059 on C2 myoblast differentiation and identify the pathway(s) underlying PD-induced C2 myoblast differentiation.