Relationship between myosin heavy chain IId isoform and fibre types in soleus muscle of the rat after hindlimb suspension

1993 ◽  
Vol 66 (5) ◽  
pp. 451-454 ◽  
Author(s):  
Yasuharu Oishi
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Fibre Types ◽  
Hindlimb Suspension

Distribution of myosin heavy chain isoforms in non-weight-bearing rat soleus muscle fibers

1996 ◽  
Vol 81 (6) ◽  
pp. 2540-2546 ◽  
Author(s):  
Robert J. Talmadge ◽  
Roland R. Roy ◽  
V. Reggie Edgerton
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
De Novo ◽  
Weight Bearing ◽  
Muscle Fibers ◽  
Myosin Heavy Chain Isoforms ◽  
Hindlimb Suspension ◽  
Type I ◽  
Rat Soleus Muscle

Talmadge, Robert J., Roland R. Roy, and V. Reggie Edgerton.Distribution of myosin heavy chain isoforms in non-weight-bearing rat soleus muscle fibers. J. Appl. Physiol. 81(6): 2540–2546, 1996.—The effects of 14 days of spaceflight (SF) or hindlimb suspension (HS) (Cosmos 2044) on myosin heavy chain (MHC) isoform content of the rat soleus muscle and single muscle fibers were determined. On the basis of electrophoretic analyses, there was a de novo synthesis of type IIx MHC but no change in either type I or IIa MHC isoform proportions after either SF or HS compared with controls. The percentage of fibers containing only type I MHC decreased by 26 and 23%, and the percentage of fibers with multiple MHCs increased from 6% in controls to 32% in HS and 34% in SF rats. Type IIx MHC was always found in combination with another MHC or combination of MHCs; i.e., no fibers contained type IIx MHC exclusively. These data suggest that the expression of the normal complement of MHC isoforms in the adult rat soleus muscle is dependent, in part, on normal weight bearing and that the absence of weight bearing induces a shift toward type IIx MHC protein expression in the preexisting type I and IIa fibers of the soleus.

In vivo regulation of the β-myosin heavy chain gene in soleus muscle of suspended and weight-bearing rats

2000 ◽  
Vol 278 (6) ◽  
pp. C1153-C1161 ◽  
Author(s):  
Julia M. Giger ◽  
Fadia Haddad ◽  
Anqi X. Qin ◽  
Kenneth M. Baldwin
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Weight Bearing ◽  
Hindlimb Suspension ◽  
Luciferase Reporter ◽  
Chain Gene ◽  
Direct Gene Transfer ◽  
Luciferase Reporter Gene

In the weight-bearing hindlimb soleus muscle of the rat, ∼90% of muscle fibers express the β-myosin heavy chain (β-MHC) isoform protein. Hindlimb suspension (HS) causes the MHC isoform population to shift from β toward the fast MHC isoforms. Our aim was to establish a model to test the hypothesis that this shift in expression is transcriptionally regulated through specific cis elements of the β-MHC promoter. With the use of a direct gene transfer approach, we determined the activity of different length β-MHC promoter fragments, linked to a firefly luciferase reporter gene, in soleus muscle of control and HS rats. In weight-bearing rats, the relative luciferase activity of the longest β-promoter fragment (−3500 bp) was threefold higher than the shorter promoter constructs, which suggests that an enhancer sequence is present in the upstream promoter region. After 1 wk of HS, the reporter activities of the −3500-, −914-, and −408-bp promoter constructs were significantly reduced (∼40%), compared with the control muscles. However, using the −215-bp construct, no differences in promoter activity were observed between HS and control muscles, which indicates that the response to HS in the rodent appears to be regulated within the −408 and −215 bp of the promoter.

Mechanical load affects growth and maturation of skeletal muscle grafts

1995 ◽  
Vol 78 (1) ◽  
pp. 30-37 ◽  
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.

scholarly journals Evidence of MyomiR network regulation of β-myosin heavy chain gene expression during skeletal muscle atrophy

2009 ◽  
Vol 39 (3) ◽  
pp. 219-226 ◽  
Author(s):  
John J. McCarthy ◽  
Karyn A. Esser ◽  
Charlotte A. Peterson ◽  
Esther E. Dupont-Versteegden
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Myosin Heavy Chain ◽  
Muscle Atrophy ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Hindlimb Suspension ◽  
Chain Gene ◽  
Heavy Chain Gene ◽  
Myosin Heavy Chain Gene

There is a growing recognition that noncoding RNAs (ncRNA) play an important role in the regulation of gene expression. A class of small (19–22 nt) ncRNAs, known as microRNAs (miRs), have received a great deal of attention lately because of their ability to repress gene expression through a unique posttranscriptional 3′-untranslated region (UTR) mechanism. The objectives of the current study were to identify miRs expressed in the rat soleus muscle and determine if their expression was changed in response to hindlimb suspension. Comprehensive profiling revealed 151 miRs were expressed in the soleus muscle and expression of 18 miRs were significantly ( P < 0.01) changed after 2 and/or 7 days of hindlimb suspension. The significant decrease (16%) in expression of muscle-specific miR-499 in response to hindlimb suspension was confirmed by RT-PCR and suggested activation of the recently proposed miR encoded by myosin gene (MyomiR) network during atrophy. Further analysis of soleus muscle subjected to hindlimb suspension for 28 days provided evidence consistent with MyomiR network repression of β-myosin heavy chain gene (β-MHC) expression. The significant downregulation of network components miR-499 and miR-208b by 40 and 60%, respectively, was associated with increased expression of Sox6 (2.2-fold) and Purβ (23%), predicted target genes of miR-499 and known repressors of β-MHC expression. A Sox6 3′-UTR reporter gene confirmed Sox6 is a target gene of miR-499. These results further expand the role of miRs in adult skeletal muscle and are consistent with a model in which the MyomiR network regulates slow myosin expression during muscle atrophy.

Effect of unloading on type I myosin heavy chain gene regulation in rat soleus muscle

2005 ◽  
Vol 98 (4) ◽  
pp. 1185-1194 ◽  
Author(s):  
Julia M. Giger ◽  
Fadia Haddad ◽  
Anqi X. Qin ◽  
Ming Zeng ◽  
Kenneth M. Baldwin
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Regulatory Elements ◽  
Hindlimb Suspension ◽  
Type I ◽  
Transcriptional Enhancer ◽  
Western Blots ◽  
E Box ◽  
Enhancer Factor

Slow-twitch soleus, a weight-bearing hindlimb muscle, predominantly expresses the type I myosin heavy chain (MHC) isoform. However, under unloading conditions, a transition in MHC expression occurs from slow type I toward the fast-type isoforms. Transcriptional processes are believed to be involved in this adaptation. To test the hypothesis that the downregulation of MHC1 in soleus muscle following unloading is controlled through cis element(s) in the proximal region of the promoter, the MHC1 promoter was injected into soleus muscles of control rats and those subjected to 7 days of hindlimb suspension. Mutation analyses of six putative regulatory elements within the −408-bp region demonstrated that three elements, an A/T-rich, the proximal muscle-type CAT (βe3), and an E-box (−63 bp), play an important role in the basal level of MHC1 gene activity in the control soleus and function as unloading-responsive elements. Gel mobility shift assays revealed a diminished level of complex formation of the βe3 and E-box probes with nuclear extract from hindlimb suspension soleus compared with control soleus. Supershift assays indicated that transcriptional enhancer factor 1 and myogenin factors bind the βe3 and E-box elements, respectively, in the control soleus. Western blots showed that the relative concentrations of the transcriptional enhancer factor 1 and myogenin factors were significantly attenuated in the unloaded soleus compared with the control muscle. We conclude that the downregulation of MHC1 in response to unloading is due, in part, to a significant decrease in the concentration of these transcription factors available for binding the positive regulatory elements.

Time-dependent changes in myosin heavy chain mRNA and protein isoforms in unloaded soleus muscle of rat

1999 ◽  
Vol 277 (6) ◽  
pp. C1044-C1049 ◽  
Author(s):  
Laurence Stevens ◽  
Karim R. Sultan ◽  
Heidemarie Peuker ◽  
Bärbel Gohlsch ◽  
Yvonne Mounier ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Time Course ◽  
Mrna Level ◽  
Protein Isoforms ◽  
Time Dependent ◽  
Hindlimb Suspension ◽  
Intermediate Step ◽  
Whole Muscle

Time-dependent changes in myosin heavy chain (MHC) isoform expression were investigated in rat soleus muscle unloaded by hindlimb suspension. Changes at the mRNA level were measured by RT-PCR and correlated with changes in the pattern of MHC protein isoforms. Protein analyses of whole muscle revealed that MHCI decreased after 7 days, when MHCIIa had increased, reaching a transient maximum by 15 days. Longer periods led to inductions and progressive increases of MHCIId(x) and MHCIIb. mRNA analyses of whole muscle showed that MHCIId(x) displayed the steepest increase after 4 days and continued to rise until 28 days, the longest time period investigated. MHCIIb mRNA followed a similar time course, although at lower levels. MHCIα mRNA, present at extremely low levels in control soleus, peaked after 4 days, stayed elevated until 15 days, and then decayed. Immunohistochemistry of 15-day unloaded muscles revealed that MHCIα was present in muscle spindles but at low amounts also in extrafusal fibers. The slow-to-fast transitions thus seem to proceed in the order MHCIβ → MHCIIa → MHCIId(x) → MHCIIb. Our findings indicate that MHCIα is transiently upregulated in some fibers as an intermediate step during the transition from MHCIβ to MHCIIa.

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