Effect of mechanical load on acetylcholinesterase mRNA levels in the slow soleus muscle of the rat

The present experiment was designed to examine the effects of hypothyroidism and calcineurin inhibition induced by cyclosporin A (CsA) administration on both contractile and metabolic soleus muscle phenotypes, with a novel approach to the signaling pathway controlling mitochondrial biogenesis. Twenty-eight rats were randomly assigned to four groups, normothyroid, hypothyroid, and orally treated with either CsA (25 mg/kg, N-CsA and H-CsA) or vehicle (N-Vh and H-Vh), for 3 wk. Muscle phenotype was estimated by the MHC profile and activities of oxidative and glycolytic enzymes. We measured mRNA levels of the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), the major regulator of mitochondrial content. We also studied the expression of the catalytic A-subunit of calcineurin (CnA) both at protein and transcript levels and mRNA levels of modulatory calcineurin inhibitor proteins (MCIP)-1 and -2, which are differentially regulated by calcineurin activity and thyroid hormone, respectively. CsA-administration induced a slow-to-fast MHC transition limited to the type IIA isoform, which is associated with increased oxidative capacities. Hypothyroidism strongly decreased both the expression of fast MHC isoforms and oxidative capacities. Effects of CsA administration on muscle phenotype were blocked in conditions of thyroid hormone deficiency. Changes in the oxidative profile were strongly related to PGC-1α changes and associated with phosphorylation of p38 MAPK. Calcineurin and MCIPs mRNA levels were decreased by both hypothyroidism and CsA without additive effects. Taken together, these results suggest that adult muscle phenotype is primarily under the control of thyroid state. Physiological levels of thyroid hormone are required for the effects of calcineurin inhibition on slow oxidative muscle phenotype.

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Activity-Linked Regulation of Acetylcholinesterase mRNA Levels Involves Distinct Molecular Mechanisms in Developing Versus Adult Skeletal Muscles

Structure and Function of Cholinesterases and Related Proteins ◽

10.1007/978-1-4899-1540-5_26 ◽

1998 ◽

pp. 128-129

Author(s):

Céline Boudreau-Larivière ◽

Roxanne Y. Y. Chan ◽

Bernard J. Jasmin

Keyword(s):

Skeletal Muscles ◽

Molecular Mechanisms ◽

Mrna Levels ◽

Acetylcholinesterase Mrna

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Antisense inhibition of myoD expression in regenerating rat soleus muscle is followed by an increase in the mRNA levels of myoD, myf-5 and myogenin and by a retarded regeneration

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research ◽

10.1016/s0167-4889(02)00198-2 ◽

2002 ◽

Vol 1590 (1-3) ◽

pp. 52-63 ◽

Cited By ~ 13

Author(s):

Ernő Zádor ◽

Sándor Bottka ◽

Frank Wuytack

Keyword(s):

Soleus Muscle ◽

Mrna Levels ◽

Antisense Inhibition ◽

Rat Soleus Muscle ◽

Myod Expression

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Skeletal muscle myostatin mRNA expression is fiber-type specific and increases during hindlimb unloading

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1999.277.2.r601 ◽

1999 ◽

Vol 277 (2) ◽

pp. R601-R606 ◽

Cited By ~ 74

Author(s):

Christian J. Carlson ◽

Frank W. Booth ◽

Scott E. Gordon

Keyword(s):

Skeletal Muscle ◽

Muscle Mass ◽

Soleus Muscle ◽

Fiber Type ◽

Weight Bearing ◽

Mrna Abundance ◽

Hindlimb Unloading ◽

Negative Regulator ◽

Type I ◽

Mrna Levels

Transgenic mice lacking a functional myostatin (MSTN) gene demonstrate greater skeletal muscle mass resulting from muscle fiber hypertrophy and hyperplasia (McPherron, A. C., A. M. Lawler, and S.-J. Lee. Nature 387: 83–90, 1997). Therefore, we hypothesized that, in normal mice, MSTN may act as a negative regulator of muscle mass. Specifically, we hypothesized that the predominately slow (type I) soleus muscle, which demonstrates greater atrophy than the fast (type II) gastrocnemius-plantaris complex (Gast/PLT), would show more elevation in MSTN mRNA abundance during hindlimb unloading (HU). Surprisingly, MSTN mRNA was not detectable in weight-bearing or HU soleus muscle, which atrophied 42% by the 7th day of HU in female ICR mice. In contrast, MSTN mRNA was present in weight-bearing Gast/PLT muscle and was significantly elevated (67%) at 1 day but not at 3 or 7 days of HU. However, the Gast/PLT muscle had only atrophied 17% by the 7th day of HU. Because the soleus is composed only of type I and IIa fibers, whereas the Gast/PLT expresses type IId/x and IIb in addition to type I and IIa, it was necessary to perform a more careful analysis of the relationship between MSTN mRNA levels and myosin heavy-chain (MHC) isoform expression (as a marker of fiber type). A significant correlation ( r = 0.725, P < 0.0005) was noted between the percentage of MHC isoform IIb expression and MSTN mRNA abundance in several muscles of the mouse hindlimb. These results indicate that MSTN expression is not strongly associated with muscle atrophy induced by HU; however, it is strongly associated with MHC isoform IIb expression in normal muscle.

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Role of IGF-I and IGFBPs in the changes of mass and phenotype induced in rat soleus muscle by clenbuterol

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2002.282.1.e31 ◽

2002 ◽

Vol 282 (1) ◽

pp. E31-E37 ◽

Cited By ~ 53

Author(s):

Bonaventure L. Awede ◽

Jean-Paul Thissen ◽

Jean Lebacq

Keyword(s):

Soleus Muscle ◽

Muscle Hypertrophy ◽

Mrna Levels ◽

Fivefold Increase ◽

Igf I ◽

Female Wistar Rats ◽

Igf Binding ◽

Rat Soleus Muscle ◽

Igf Binding Protein

Clenbuterol induces hypertrophy and a slow-to-fast phenotype change in skeletal muscle, but the signaling mechanisms remain unclear. We hypothesized that clenbuterol could act via local expression of insulin-like growth factor I (IGF-I). Administration of clenbuterol to 3-mo-old female Wistar rats resulted in a 10 and 13% increase of soleus muscle mass after 3 and 9 days, respectively, reaching 16% after 4 wk. When associated with triiodothyronine, clenbuterol induced a dramatic slow-to-fast phenotype change. In parallel, clenbuterol administration induced in soleus muscle a fivefold increase in IGF-I mRNA levels associated with an eightfold increase in IGF-binding protein (IGFBP)-4 and a fivefold increase of IGFBP-5 mRNA levels on day 3. This increased IGF-I gene expression was associated with an increase in muscle IGF-I content, already detected on day 1 and persisting until day 5 without increase in serum IGF-I concentrations. These data show that muscle hypertrophy induced by clenbuterol is associated with a local increase in muscle IGF-I content. They suggest that clenbuterol-induced muscle hypertrophy could be mediated by local production of IGF-I.

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Skeletal muscle collagen type I and III mRNA, [corrected] prolyl 4-hydroxylase, and collagen in hypobaric trained rats

Journal of Applied Physiology ◽

10.1152/jappl.1996.80.6.2226 ◽

1996 ◽

Vol 80 (6) ◽

pp. 2226-2233 ◽

Cited By ~ 8

Author(s):

M. Perhonen ◽

X. Han ◽

W. Wang ◽

J. Karpakka ◽

T. E. Takala

Keyword(s):

Skeletal Muscle ◽

Soleus Muscle ◽

Collagen Type ◽

Mrna Level ◽

Collagen Type I ◽

Synthesis Rate ◽

Type I ◽

Mrna Levels ◽

Edl Muscle ◽

And Training

Skeletal muscle collagen expression was studied in normobaric sedentary (NS) and training (NT) and hypobaric sedentary (HS) and training (HT) rats after experimental periods of 10, 21, and 56 days. The weights of fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus muscles were increased between the experimental period of 21 and 56 days so that EDL weight was 57 (P < 0.01) and 36% (P < 0.05) higher in 56 days HS (56HS) and 56 days HT (56HT), respectively, than in 56 days NS (56NS). Soleus muscle weight was higher in 56HS (61%; P < 0.01) and in 56HT (27%; P < 0.05) than in 56NT. In EDL muscle, collagen type I mRNA level was lower in 56HT than in 56NS (36%; P < 0.05) and 56NT (44%; P < 0.01). In 56HT, collagen type III mRNA level was 39 (P < 0.01) and 42% (P < 0.05) lower than in 56NS and 56HS, respectively. In soleus muscle, prolyl 4-hydroxylase activity was greater (P < 0.05) in 56NT, 56HS, and 56HT than in 56NS. Total hydroxyproline content in EDL muscle was increased in 56HS and 56HT and in soleus muscle of 56HS. In conclusion, although collagen types I and III mRNA levels in EDL muscle decreased in 56HT, the prolyl 4-hydroxylase data suggest unchanged synthesis of total collagen. Exposure to hypobaric conditions as such, its combination to endurance training, as well as training in normobaric conditions increased prolyl 4-hydroxylation capacity in soleus muscle, which may indicate respective change in collagen synthesis rate.

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Myosin heavy chain of immature soleus muscle grafts adapts to hyperthyroidism more than to physical activity

Journal of Applied Physiology ◽

10.1152/jappl.1996.80.3.789 ◽

1996 ◽

Vol 80 (3) ◽

pp. 789-794 ◽

Cited By ~ 8

Author(s):

S. T. Devor ◽

T. P. White

Keyword(s):

Physical Activity ◽

Myosin Heavy Chain ◽

Soleus Muscle ◽

Heavy Chain ◽

Adaptive Response ◽

Mechanical Load ◽

Normal Load ◽

Type I ◽

Thyroid Status ◽

Early Regeneration

The interaction of hyperthyroidism and the elements of physical activity on early regeneration of muscle grafts was investigated. Soleus muscle grafts were studied 15 days after graft operations in eu- and hyperthyroid rats. Hypotheses were tested regarding the adaptation of the myosin heavy chain (MHC) profile of grafts and nongrafted control muscles and whether the effect of hyperthyroidism would predominate over the opposing influence of recruitment and mechanical load on MHC of grafts. Denervation and myectomy of synergist muscles were employed to manipulate the elements of physical activity. Denervation decreased the expression of type I MHC, and hyperthyroidism furthered the shift toward a “fast” isoform profile. For example, in denervated grafts, type IIb was undetected in euthyroid rats and accounted for 31% of MHC in hyperthyroid rats. Compared with control muscles, grafts in the denervated and innervated-normal load groups demonstrated greater plasticity because the adaptive response of MHC to thyroid status was more pronounced. Hyperthyroidism predominated over the opposing influence of the elements of physical activity on the regulation of MHC expression in innervated plus overload grafts. For example, type I MHC was 86% of MHC profile of innervated plus overload grafts in euthyroid rats and was only 49% in hyperthyroid rats. In conclusion, a heightened plasticity for grafts was evidenced in denervated and innervated tissues, and the regulation of MHC by thyroid hormone predominated over that due to the elements of physical activity.

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Mechanical load affects growth and maturation of skeletal muscle grafts

Journal of Applied Physiology ◽

10.1152/jappl.1995.78.1.30 ◽

1995 ◽

Vol 78 (1) ◽

pp. 30-37 ◽

Cited By ~ 17

Author(s):

K. A. Esser ◽

T. P. White

Keyword(s):

Skeletal Muscle ◽

Myosin Heavy Chain ◽

Mechanical Loading ◽

Soleus Muscle ◽

Heavy Chain ◽

Mechanical Load ◽

Normal Load ◽

Growth Characteristics ◽

Lower Proportion ◽

Hindlimb Suspension

The purpose of our study was to determine whether the early patterns of growth and maturation of regenerating soleus muscle grafts are sensitive to alterations in mechanical load. We hypothesized that decreased and increased mechanical loading of grafts would reduce and accelerate, respectively, the rate and magnitude of growth and impair and enhance, respectively, the pattern of maturation. On day 0, soleus muscles were grafted and rats were assigned to one of three groups: cage sedentary (normal load), hindlimb suspension (decreased load), or ablation of synergist muscle (increased load). From days 7 to 35, graft mass in cage-sedentary rats increased at a rate of 1.85 mg mass/day. Rates were less for grafts of suspended rats and greater in grafts of ablated rats (-1.06 and 3.89 mg mass/day, respectively; P < 0.01). Neonatal myosin heavy chain (MHC) in grafts reached 10 +/- 1.6% of total MHC at day 7 for cage-sedentary rats, whereas in the suspended animals it reached 11 +/- 2.4% of total MHC at day 14. At days 21 and 35, grafts from the suspended animals had a lower proportion of slow MHC (45 +/- 2.4%) than did grafts from the control and ablated groups (95 +/- 1.5%; P < 0.05). Decreased mechanical load impaired the rate and degree of growth and maturation during regeneration, whereas increased mechanical load enhanced growth characteristics but not maturation.

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