The expression of myogenic regulatory factors and muscle growth factors in the masticatory muscles of dystrophin-deficient (MDX) mice

Abstract

Abstract:The activities of myogenic regulatory factors (MRF) and muscle growth factors increase in muscle that is undergoing regeneration, and may correspond to some specific changes. Little is known about the role of MRFs in masticatory muscles in mdx mice (the model of Duchenne muscular dystrophy) and particularly about their mRNA expression during the process of muscle regeneration. Using Taqman RT-PCR, we examined the mRNA expression of the MRFs myogenin and MyoD1 (myogenic differentiation 1), and of the muscle growth factors myostatin, IGF1 (insulin-like growth factor) and MGF (mechanogrowth factor) in the masseter, temporal and tongue masticatory muscles of mdx mice (n = 6 to 10 per group). The myogenin mRNA expression in the mdx masseter and temporal muscle was found to have increased (P < 0.05), whereas the myostatin mRNA expressions in the mdx masseter (P < 0.005) and tongue (P < 0.05) were found to have diminished compared to those for the controls. The IGF and MGF mRNA amounts in the mdx mice remained unchanged. Inside the mdx animal group, gender-related differences in the mRNA expressions were also found. A higher mRNA expression of myogenin and MyoD1 in the mdx massterer and temporal muscles was found in females in comparison to males, and the level of myostatin was higher in the masseter and tongue muscle (P < 0.001 for all comparisons). Similar gender-related differences were also found within the control groups. This study reveals the intermuscular differences in the mRNA expression pattern of myogenin and myostatin in mdx mice. The existence of these differences implies that dystrophinopathy affects the skeletal muscles differentially. The finding of gender-related differences in the mRNA expression of the examined factors may indicate the importance of hormonal influences on muscle regeneration.

Dual Myostatin and Dystrophin Exon Skipping by Morpholino Nucleic Acid Oligomers Conjugated to a Cell-penetrating Peptide Is a Promising Therapeutic Strategy for the Treatment of Duchenne Muscular Dystrophy

“…27 In contrast, in different muscles of mdx mice there seems to be variability in myostatin expression. 28 However, no studies have been performed to clarify whether TA muscles of mdx mice show gender-specific differences in myostatin expression. A possible explanation of the gender-specific difference observed in our study is that the hypertrophic effect induced by our dose regimen of B-PMO-mstn was still not efficient enough to be observed in the pseudohypertrophic mdx male muscles.…”

Myogenic differentiation factor 1 and myogenin expression not elevated in regenerated masticatory muscles of dystrophic (mdx) mice

“…Myogenin mRNA expression in both mdx masseter and temporal muscles increased [21], whereas the protein expression demonstrated in this study changed little or not at all. This may have to do with the fact that changes in gene expression of myogenin during transcription may not be immediately translated into proteins.…”

“…Die Expression von Myogenin mRNA sowohl in den Masseter-als auch in den Temporalmuskeln von mdx-Mäusen stieg an [21], während die Proteinexpression, wie wir in der vorliegenden Studie herausgefunden haben, sich wenig bzw. gar nicht veränderte.…”

Talin, Vinculin and Nestin Expression in Orofacial Muscles of Dystrophin Deficient mdx Mice

“…In this respect most studies concentrated their attention on mdx hindlimb muscles. In contrast, our research group has focused primarily on mdx orofacial muscles showing that they not only have similarities but also differences in the response to dystrophin deficiency when compared to hindlimb muscles (Spassov et al 2010(Spassov et al , 2011b. Fig.…”