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S Bayol

Publications and source records attributed to S Bayol.

6 recordsLinked to original sources
PubMed2000

Phenotypic expression of IGF binding protein transcripts in muscle, in vitro and in vivo.

The actions of the insulin-like growth factors (IGF-I and IGF-II) which are essential components of skeletal muscle growth are mediated via their receptors and modulated by six binding proteins (IGFBPs). We studied IGFBP transcripts in C2C12 cell cultures and in adult control and denervated gastrocnemius muscle. IGFBP-2, -4, -5, and -6 were detected in C2C12 cells. IGFBP-6 mRNA levels remained unchanged, IGFBP-2 levels decreased and IGFBP-4 and -5 increased over 1, 5, and 9 days after serum reduction. In a range of adult muscles studied, IGFBP-4 mRNA levels were similar, IGFBP-5 was present at different levels in slow and fast muscles and IGFBP-6 had the lowest expression in the tibialis anterior. Denervation resulted in dramatic up-regulation of IGFBP-4 and -5 transcripts but there was no change in IGFBP-6. These results suggest that either lack of neural input and/or mechanical loading, both of which contribute to muscle atrophy, affect IGFBP expression.

Animals↗
PubMed2000

The LIM-domain protein FHL1 (SLIM 1) exhibits functional regulation in skeletal muscle.

The LIM domain protein FHL1 (SLIM 1) transcript is preferentially expressed in postnatal skeletal muscle but almost nothing is known about its function in this tissue. In this study we have examined the expression of the FHL1 transcript at the cellular level by in situ hybridisation. Muscle fibers exist as a number of discrete subpopulations or "types" which are differentiated by their contractile and metabolic properties. It was observed that the FHL1 transcript was not fiber-type specific but was however more abundant in oxidative fibers. Muscle atrophy induced by disuse caused a significant decline in the expression of the transcript but atrophy induced by short-term denervation did not. Hypertrophy of skeletal muscle induced by passive stretch was associated with an up-regulation of the FHL1 transcript. These data are consistent that FHL1 is involved in synthetic processes within the muscle fibre.

Animals↗
PubMed1999

The novel sarcomeric protein telethonin exhibits developmental and functional regulation.

We have isolated a cDNA clone from a mouse skeletal muscle library which is preferentially expressed in striated muscle and exhibits a high homology to human telethonin, a sarcomeric protein. The mouse telethonin transcript is developmentally regulated in both cardiac and skeletal muscle in vivo and is down-regulated in response to denervation. In the C2C12 muscle cell-line the mouse telethonin transcript exhibited a pattern of accumulation similar to that observed for a contractile protein and suggests a role in myofibrillar assembly.

Amino Acid Sequence↗
PubMedDate not supplied

Electrical stimulation modulates IGF binding protein transcript levels in C2C12 myotubes.

Electrical stimulation (ES) of skeletal muscle can produce changes in metabolic enzyme and contractile protein gene expression resulting in fast-to-slow phenotypic changes. The molecular mechanism by which ES induces changes in phenotype is not entirely understood but recent reports have demonstrated that the calcineurin/NF-AT signalling pathway is involved. IGF-1 is also capable of inducing changes in phenotype through the same calcineurin/NF-AT pathway but little is known of the direct effect of ES on the IGF system. In this study, we examined the effects of ES on the expression of igf-1, igf-2 and the six igfbp genes in the C2C12 muscle cell line. Results showed that ES induced a change in phenotype that was accompanied by downregulation of igf-2 and upregulation of igfbp-4 mRNA levels. However, ES did not significantly alter the transcription of igf-1, igfbp-2, igfbp-5 and igfbp-6 genes. This study demonstrates that ES of muscle cells in vitro not only directly modulates the gene expression of contractile proteins but also modulates proteins that are part of the IGF regulatory system, in particular IGFBP-4.

Animals↗