Time-dependent changes in expression of troponin subunit isoforms in unloaded rat soleus muscle

2002 ◽  
Vol 282 (5) ◽  
pp. C1025-C1030 ◽  
Author(s):  
Laurence Stevens ◽  
Bruno Bastide ◽  
Philippe Kischel ◽  
Dirk Pette ◽  
Yvonne Mounier
Keyword(s):  
Soleus Muscle ◽  
Troponin I ◽  
Troponin T ◽  
Hindlimb Unloading ◽  
Heavy Chains ◽  
Mechanical Unloading ◽  
Fast Myosin ◽  
Rat Soleus Muscle ◽  
Subunit Isoforms ◽  
Time Courses

This study focuses on the effects of mechanical unloading of rat soleus muscle on the isoform patterns of the three troponin (Tn) subunits: troponin T (TnT), troponin I (TnI), and troponin C (TnC). Mechanical unloading was achieved by hindlimb unloading (HU) for time periods of 7, 15, and 28 days. Relative concentrations of slow and fast TnT, TnI, and TnC isoforms were assessed by electrophoretic and immunoblot analyses. HU induced profound slow-to-fast isoform transitions of all Tn subunits, although to different extents and with different time courses. The effectiveness of the isoform transitions was higher for TnT than for TnI and TnC. Indeed, TnI and TnC encompassed minor partial exchanges of slow isoforms with their fast counterparts, whereas the expression pattern of fast TnT isoforms (TnTf) was largely increased after HU. Moreover, slow and fast isoforms of the different Tn were not affected in the same manner by HU. This suggests that the slow and fast counterparts of the Tn subunit isoforms are regulated independently in response to HU. The changes in TnTf composition occurred in parallel with previously demonstrated transitions within the pattern of the fast myosin heavy chains in the same muscles.

Myosin and troponin changes in rat soleus muscle after hindlimb suspension

1993 ◽  
Vol 74 (3) ◽  
pp. 1156-1160 ◽  
Author(s):  
M. Campione ◽  
S. Ausoni ◽  
C. Y. Guezennec ◽  
S. Schiaffino
Keyword(s):  
Soleus Muscle ◽  
Troponin I ◽  
Troponin T ◽  
High Mobility ◽  
Calcium Sensitivity ◽  
Hindlimb Suspension ◽  
Type I ◽  
Maximal Velocity ◽  
Rat Soleus Muscle ◽  
Fast Twitch

We examined the myosin heavy-chain (MHC), troponin T (TnT), and troponin I (TnI) isoform composition in the rat soleus muscle after 21 days of hindlimb suspension using electrophoretic and immunoblotting analysis with specific monoclonal antibodies. The suspended soleus showed a shift in the MHC isoform distribution with a marked increase (from 1.0 to 33%) in the relative amount of type IIa and IIx MHC and a corresponding decrease in type I MHC. However, type IIb MHC, which represents a major component in fast-twitch muscles, was not detected in suspended soleus muscles. TnT and TnI isoform composition was also changed with the appearance of fast-type TnI and TnT bands. However, a high-mobility TnT band, which represents a major component in fast-twitch muscles, was not expressed in suspended soleus. These isoform transitions may be related to the increased maximal velocity of shortening and higher calcium sensitivity previously reported in the rat soleus after hindlimb suspension.

scholarly journals Differential regulation of myofilament protein isoforms underlying the contractility changes in skeletal muscle unloading

2007 ◽  
Vol 292 (3) ◽  
pp. C1192-C1203 ◽  
Author(s):  
Zhi Bin Yu ◽  
Fang Gao ◽  
Han Zhong Feng ◽  
Jian-Ping Jin
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Troponin I ◽  
Troponin T ◽  
Weight Bearing ◽  
Regulatory Protein ◽  
Differential Regulation ◽  
Hindlimb Unloading ◽  
Protein Isoforms ◽  
Hindlimb Suspension

Weight-bearing skeletal muscles change phenotype in response to unloading. Using the hindlimb suspension rat model, we investigated the regulation of myofilament protein isoforms in correlation to contractility. Four weeks of continuous hindlimb unloading produced progressive atrophy and contractility changes in soleus but not extensor digitorum longus muscle. The unloaded soleus muscle also had decreased fatigue resistance. Along with the decrease of myosin heavy chain isoform I and IIa and increase of IIb and IIx, coordinated regulation of thin filament regulatory protein isoforms were observed: γ- and β-tropomyosin decreased and α-tropomyosin increased, resulting in an α/β ratio similar to that in normal fast twitch skeletal muscle; troponin I and troponin T (TnT) both showed decrease in the slow isoform and increases in the fast isoform. The TnT isoform switching began after 7 days of unloading and TnI isoform showed detectable changes at 14 days while other protein isoform changes were not significant until 28 days of treatment. Correlating to the early changes in contractility, especially the resistance to fatigue, the early response of TnT isoform regulation may play a unique role in the adaptation of skeletal muscle to unloading. When the fast TnT gene expression was upregulated in the unloaded soleus muscle, alternative RNA splicing switched to produce more high molecular weight acidic isoforms, reflecting a potential compensation for the decrease of slow TnT that is critical to skeletal muscle function. The results demonstrate that differential regulation of TnT isoforms is a sensitive mechanism in muscle adaptation to functional demands.

scholarly journals Sex differences in forkhead box O3a signaling response to hindlimb unloading in rat soleus muscle

2018 ◽  
Vol 69 (2) ◽  
pp. 235-244 ◽  
Author(s):  
Toshinori Yoshihara ◽  
Toshiharu Natsume ◽  
Takamasa Tsuzuki ◽  
Shuo-wen Chang ◽  
Ryo Kakigi ◽  
...  
Keyword(s):  
Sex Differences ◽  
Soleus Muscle ◽  
Hindlimb Unloading ◽  
Forkhead Box ◽  
Rat Soleus Muscle ◽  
Forkhead Box O3a

scholarly journals Effect of L-Arginine on Titin Expression in Rat Soleus Muscle After Hindlimb Unloading

2019 ◽  
Vol 10 ◽  
Author(s):  
Anna Ulanova ◽  
Yuliya Gritsyna ◽  
Nikolai Salmov ◽  
Yuliya Lomonosova ◽  
Svetlana Belova ◽  
...  
Keyword(s):  
Soleus Muscle ◽  
Hindlimb Unloading ◽  
Rat Soleus Muscle

Analysis by two-dimensional Blue Native/SDS-PAGE of membrane protein alterations in rat soleus muscle after hindlimb unloading

2010 ◽  
Vol 110 (6) ◽  
pp. 1215-1224 ◽  
Author(s):  
Davide Basco ◽  
Grazia Paola Nicchia ◽  
Jean-François Desaphy ◽  
Diana Conte Camerino ◽  
Antonio Frigeri ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Soleus Muscle ◽  
Hindlimb Unloading ◽  
Two Dimensional ◽  
Sds Page ◽  
Rat Soleus Muscle ◽  
Protein Alterations ◽  
Blue Native

Preventive effect of nucleoprotein on hindlimb unloading-induced capillary regression in rat soleus muscle

2013 ◽  
Vol 89 (3) ◽  
pp. 220-227 ◽  
Author(s):  
Y Kanazawa ◽  
K Maekawa ◽  
Y Okumura ◽  
N Fujita ◽  
H Fujino
Keyword(s):  
Soleus Muscle ◽  
Hindlimb Unloading ◽  
Preventive Effect ◽  
Rat Soleus Muscle

scholarly journals Key Markers of mTORC1-Dependent and mTORC1-Independent Signaling Pathways Regulating Protein Synthesis in Rat Soleus Muscle During Early Stages of Hindlimb Unloading

2016 ◽  
Vol 39 (3) ◽  
pp. 1011-1020 ◽  
Author(s):  
Timur Mirzoev ◽  
Sergey Tyganov ◽  
Natalia Vilchinskaya ◽  
Yulia Lomonosova ◽  
Boris Shenkman
Keyword(s):  
Protein Synthesis ◽  
Signaling Pathways ◽  
Soleus Muscle ◽  
Ribosome Biogenesis ◽  
Hindlimb Unloading ◽  
Hindlimb Suspension ◽  
28S Rrna ◽  
Early Stages ◽  
Global Rate ◽  
Rat Soleus Muscle

Background/Aims: The purpose of the study was to assess the amount of rRNA and phosphorylation status of the key markers of mTORC1-dependent (70s6k, 4E-BP1) and mTORC1-independent (GSK-3β, AMPK) signaling pathways controlling protein synthesis in rat soleus during early stages of mechanical unloading (hindlimb suspension (HS) for 1-, 3- and 7 days). Methods: The content of the key signaling molecules of various anabolic signaling pathways was determined by Western-blotting. The amount of 28S rRNA was evaluated by RT-PCR. The rate of protein synthesis was assessed using in-vivo SUnSET technique. Results: HS for 3 and 7 days induced a significant (p<0.05) decrease in the rate of global protein synthesis in soleus muscle in comparison with control. HS within 24 hours resulted in a significant (p<0.05) decrease in p-4E-BP1 content, p-AMPK content and increase in p-p70s6k content in rat soleus muscle. Following three days of HS the content of p-AKT was decreased (p<0.05). After 7 days of HS the phosphorylation level of AKT and GSK-3beta was significantly reduced (p<0.05) compared to control. We also observed a significant decrease in the amount of 28S rRNA in rat soleus following 1, 3 and 7 days of HS. Conclusion: Taken together, the results of our study suggest that a decline in the global rate of protein synthesis in rat soleus during early stages of simulated microgravity is associated with impaired ribosome biogenesis as well as reduced activity of mTORC1-independent signaling pathways.

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