scholarly journals Improvement of Contraction Force in Injured Skeletal Muscle after Autologous Mesenchymal Stroma Cell Transplantation Is Accompanied by Slow to Fast Fiber Type Shift

2013 ◽  
Vol 40 (6) ◽  
pp. 2-2 ◽  
Author(s):  
Philipp von Roth ◽  
Tobias Winkler ◽  
Kristina Rechenbach ◽  
Piotr. Radojewski ◽  
Carsten Perka ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cell Transplantation ◽  
Fiber Type ◽  
Contraction Force ◽  
Stroma Cell ◽  
Fast Fiber ◽  
Mesenchymal Stroma ◽  
Type Shift

scholarly journals Effects of sarcolipin deletion on skeletal muscle adaptive responses to functional overload and unload

2017 ◽  
Vol 313 (2) ◽  
pp. C154-C161 ◽  
Author(s):  
Val A. Fajardo ◽  
Bradley A. Rietze ◽  
Paige J. Chambers ◽  
Catherine Bellissimo ◽  
Eric Bombardier ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Ectopic Expression ◽  
Oxidative Capacity ◽  
Adaptive Responses ◽  
Slow Fiber ◽  
Fast Fiber ◽  
Fiber Number ◽  
Type Shift ◽  
Calcineurin Signaling

Overexpression of sarcolipin (SLN), a regulator of sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs), stimulates calcineurin signaling to enhance skeletal muscle oxidative capacity. Some studies have shown that calcineurin may also control skeletal muscle mass and remodeling in response to functional overload and unload stimuli by increasing myofiber size and the proportion of slow fibers. To examine whether SLN might mediate these adaptive responses, we performed soleus and gastrocnemius tenotomy in wild-type (WT) and Sln-null ( Sln−/−) mice and examined the overloaded plantaris and unloaded/tenotomized soleus muscles. In the WT overloaded plantaris, we observed ectopic expression of SLN, myofiber hypertrophy, increased fiber number, and a fast-to-slow fiber type shift, which were associated with increased calcineurin signaling (NFAT dephosphorylation and increased stabilin-2 protein content) and reduced SERCA activity. In the WT tenotomized soleus, we observed a 14-fold increase in SLN protein, myofiber atrophy, decreased fiber number, and a slow-to-fast fiber type shift, which were also associated with increased calcineurin signaling and reduced SERCA activity. Genetic deletion of Sln altered these physiological outcomes, with the overloaded plantaris myofibers failing to grow in size and number, and transition towards the slow fiber type, while the unloaded soleus muscles exhibited greater reductions in fiber size and number, and an accelerated slow-to-fast fiber type shift. In both the Sln−/− overloaded and unloaded muscles, these findings were associated with elevated SERCA activity and blunted calcineurin signaling. Thus, SLN plays an important role in adaptive muscle remodeling potentially through calcineurin stimulation, which could have important implications for other muscle diseases and conditions.

scholarly journals The long noncoding RNA MyHC IIA/X-AS contributes to skeletal muscle myogenesis and maintains the fast fiber phenotype

2020 ◽  
Vol 295 (15) ◽  
pp. 4937-4949 ◽  
Author(s):  
Mingle Dou ◽  
Ying Yao ◽  
Lu Ma ◽  
Xiaoyu Wang ◽  
Xin'e Shi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Skeletal Muscles ◽  
Fiber Type ◽  
Muscle Fiber Type ◽  
Fast Fiber ◽  
Slow Type ◽  
Myhc Expression

Mammalian skeletal muscles comprise different types of muscle fibers, and this muscle fiber heterogeneity is generally characterized by the expression of myosin heavy chain (MyHC) isoforms. A switch in MyHC expression leads to muscle fiber–type transition under various physiological and pathological conditions, but the underlying regulator coordinating the switch of MyHC expression remains largely unknown. Experiments reported in this study revealed the presence of a skeletal muscle–specific antisense transcript generated from the intergenic region between porcine MyHC IIa and IIx and is referred to here as MyHC IIA/X-AS. We found that MyHC IIA/X-AS is identified as a long noncoding RNA (lncRNA) that is strictly expressed in skeletal muscles and is predominantly distributed in the cytoplasm. Genetic analysis disclosed that MyHC IIA/X-AS stimulates cell cycle exit of skeletal satellite cells and their fusion into myotubes. Moreover, we observed that MyHC IIA/X-AS is more enriched in fast-twitch muscle and represses slow-type gene expression and thereby maintains the fast phenotype. Furthermore, we found that MyHC IIA/X-AS acts as a competing endogenous RNA that sponges microRNA-130b (miR-130b) and thereby maintains MyHC IIx expression and the fast fiber type. We also noted that miR-130b was proved to down-regulate MyHC IIx by directly targeting its 3′-UTR. Together, the results of our study uncovered a novel pathway, which revealed that lncRNA derived from the skeletal MyHC cluster could modulate local MyHC expression in trans, highlighting the role of lncRNAs in muscle fiber–type switching.

scholarly journals Plantar Mechanical Stimulation Maintains Slow Myosin Expression in Disused Rat Soleus Muscle via NO-Dependent Signaling

2021 ◽  
Vol 22 (3) ◽  
pp. 1372
Author(s):  
Kristina A. Sharlo ◽  
Inna I. Paramonova ◽  
Irina D. Lvova ◽  
Ekaterina P. Mochalova ◽  
Vitaliy E. Kalashnikov ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Mechanical Stimulation ◽  
Fiber Type ◽  
Hindlimb Unloading ◽  
No Production ◽  
Mrna Transcription ◽  
Positive Effects ◽  
Myosin I ◽  
Fast Fiber ◽  
Type Shift

It was observed that gravitational unloading during space missions and simulated microgravity in ground-based studies leads to both transformation of slow-twitch muscle fibers into fast-twitch fibers and to the elimination of support afferentation, leading to the “switching-off” of postural muscle motor units electrical activity. In recent years, plantar mechanical stimulation (PMS) has been found to maintain the neuromuscular activity of the hindlimb muscles. Nitric oxide (NO) was shown to be one of the mediators of muscle fiber activity, which can also promote slow-type myosin expression. We hypothesized that applying PMS during rat hindlimb unloading would lead to NO production upregulation and prevention of the unloading-induced slow-to-fast fiber-type shift in rat soleus muscles. To test this hypothesis, Wistar rats were hindlimb suspended and subjected to daily PMS, and one group of PMS-subjected animals was also treated with nitric oxide synthase inhibitor (L-NAME). We discovered that PMS led to sustained NO level in soleus muscles of the suspended animals, and NOS inhibitor administration blocked this effect, as well as the positive effects of PMS on myosin I and IIa mRNA transcription and slow-to-fast fiber-type ratio during rat hindlimb unloading. The results of the study indicate that NOS activity is necessary for the PMS-mediated prevention of slow-to-fast fiber-type shift and myosin I and IIa mRNA transcription decreases during rat hindlimb unloading.

scholarly journals Plantar mechanical stimulation prevents calcineurin-NFATc1 inactivation and slow-to-fast fiber type shift in rat soleus muscle under hindlimb unloading

2019 ◽  
Vol 126 (6) ◽  
pp. 1769-1781 ◽  
Author(s):  
Kristina Sharlo ◽  
Inna Paramonova ◽  
Olga Turtikova ◽  
Sergey Tyganov ◽  
Boris Shenkman
Keyword(s):  
T Cells ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Mechanical Stimulation ◽  
Fiber Type ◽  
Hindlimb Unloading ◽  
Nuclear Factor ◽  
Activated T Cells ◽  
Fast Fiber ◽  
Type Shift

The prevailing myosin isoform [myosin heavy chain (MyHC)] in a skeletal muscle determines contractile properties of the muscle. Under actual or simulated microgravity conditions such as human bed rest or rat hindlimb unloading, decrease in expression of MyHC of the slow type [MyHC I(β)] has been observed. It was demonstrated that increasing sensory input by performing plantar mechanical stimulation (PMS) on the soles of the feet results in an increase in neuromuscular activation of the lower limb muscles and may prevent slow-to-fast fiber type shift. The calcineurin-nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) signaling pathway is the main cascade regulating MyHC I(β) expression. The present study was aimed to analyze the states of the calcineurin-NFATc1 signaling cascade under conditions of PMS during rat hindlimb unloading. Male Wistar rats were randomly assigned to vivarium control groups and 1-day unloading (1HS), 3-day unloading (3HS), 1HS+PMS, and 3HS+PMS groups. We found that both 1 day and 3 days of unloading caused decrease in MyHC I(β) mRNA expression and decrease in glycogen synthase kinase-3β phosphorylation (Ser 9) that brought about the kinase activation, and these effects of unloading were prevented by PMS. Three days of unloading also caused increase in expression of calsarcin-2 (myozenin-I), which was found to be the endogenous calcineurin inhibitor. The level of calsarcin-2 expression in the 3HS+PMS group did not differ from the control group. Therefore, we conclude that PMS upregulates the calcineurin-NFATc1 signaling pathway and prevents unloading-induced MyHC I(β) decrease. NEW & NOTEWORTHY It is widely accepted that changes in the myosin phenotype during functional unloading (disuse) are determined by a decreased expression of the myosin heavy chain (MyHC) I(β) gene, and this decrease leads to changes of contractile and fatigue characteristics of soleus muscle. The calcineurin-nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) pathway is one of the most important signaling cascades regulating slow MyHC isoform expression. The present study is the first to show that plantar mechanical stimulation upregulates calcineurin-NFATc1 signaling in soleus muscles of hindlimb-unloaded rats.

Complex fiber-type-specific expression of fast skeletal muscle troponin I gene constructs in transgenic mice

Development ◽  
1993 ◽  
Vol 119 (3) ◽  
pp. 691-701
Author(s):  
P.L. Hallauer ◽  
H.L. Bradshaw ◽  
K.E. Hastings
Keyword(s):  
Skeletal Muscle ◽  
Differential Expression ◽  
Expression Pattern ◽  
Troponin I ◽  
Fiber Type ◽  
Fiber Types ◽  
Fast Skeletal Muscle ◽  
Fast Fiber ◽  
Muscle Gene ◽  
High Level

We analyzed, in transgenic mice, the cellular expression pattern of the quail fast skeletal muscle troponin I (TnIfast) gene and of a chimeric reporter construct in which quail TnIfast DNA sequences drive expression of E. coli beta-galactosidase (beta-gal). Both constructs were actively expressed in skeletal muscle and specifically in fast, as opposed to slow, muscle fibers. Unexpectedly, both constructs showed a marked differential expression among the adult fast fiber subtypes according to the pattern IIB > IIX > IIA. This expression pattern was consistent in multiple lines and differed from the endogenous mouse TnIfast pattern, which shows approximately equal expression in all fast fibers. These observations indicate that distinct regulatory mechanisms contribute to high-level expression of TnIfast in the various fast fiber subtypes and suggest that the outwardly simple pattern of equal expression in all fast fiber types shown by the endogenous mouse TnIfast gene is based on an intricate system of counterbalancing mechanisms. The adult expression pattern of the TnIfast/beta-gal construct emerged in a two-stage developmental process. Differential expression in fast versus slow fibers was evident in neonatal animals, although expression in fast fibers was relatively weak and homogeneous. During the first two weeks of postnatal life, expression in maturing IIB fibers was greatly increased whereas that in IIA/IIX fibers remained weak, giving rise to marked differential expression among fast fiber types. Thus at least two serially acting (pre- and post-natal) fiber-type-specific regulatory mechanisms contribute to high-level gene expression in adult fast muscle fibers. Unexpected similarities between TnIfast transgene expression and that of the myosin heavy chain gene family (which includes differentially expressed IIB-, IIX- and IIA-specific members) suggest that similar mechanisms may regulate adult fast muscle gene expression in a variety of unrelated muscle gene families.

Continuous mild heat stress induces differentiation of mammalian myoblasts, shifting fiber type from fast to slow

2010 ◽  
Vol 298 (1) ◽  
pp. C140-C148 ◽  
Author(s):  
Tetsuo Yamaguchi ◽  
Takayoshi Suzuki ◽  
Hideaki Arai ◽  
Shihori Tanabe ◽  
Yoriko Atomi
Keyword(s):  
Skeletal Muscle ◽  
Heat Stress ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
C2c12 Cells ◽  
Muscle Repair ◽  
Local Hyperthermia ◽  
Protein Levels ◽  
Slow Fiber ◽  
Type Shift

Local hyperthermia has been widely used as physical therapy for a number of diseases such as inflammatory osteoarticular disorders, tendinitis, and muscle injury. Local hyperthermia is clinically applied to improve blood and lymphatic flow to decrease swelling of tissues (e.g., skeletal muscle). As for muscle repair following injury, the mechanisms underlying the beneficial effects of hyperthermia-induced muscle repair are unknown. In this study, we investigated the direct effects of continuous heat stress on the differentiation of cultured mammalian myoblasts. Compared with control cultures grown at 37°C, incubation at 39°C (continuous mild heat stress; CMHS) enhanced myotube diameter, whereas myotubes were poorly formed at 41°C by primary human skeletal muscle culture cells, human skeletal muscle myoblasts (HSMMs), and C2C12 mouse myoblasts. In HSMMs and C2C12 cells exposed to CMHS, mRNA and protein levels of myosin heavy chain (MyHC) type I were increased compared with the control cultures. The mRNA level of MyHC IIx was unaltered in HSMMs and decreased in C2C12 cells, compared with cells that were not exposed to heat stress. These results indicated a fast-to-slow fiber-type shift in myoblasts. We also examined upstream signals that might be responsible for the fast-to-slow shift of fiber types. CMHS enhanced the mRNA and protein levels of peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α in HSMMS and C2C12 cells but not the activities of MAPKs (ERK1/2 and p38 MAPK) in HSMMs and C2C12 cells. These data suggest that CMHS induces a fast-to-slow fiber-type shift of mammalian myoblasts through PGC-1α.

scholarly journals Activity-dependent and -independent nuclear fluxes of HDAC4 mediated by different kinases in adult skeletal muscle

2005 ◽  
Vol 168 (6) ◽  
pp. 887-897 ◽  
Author(s):  
Yewei Liu ◽  
William R. Randall ◽  
Martin F. Schneider
Keyword(s):  
Skeletal Muscle ◽  
Histone Deacetylases ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Adult Skeletal Muscle ◽  
Slow Fiber ◽  
Fast Fiber ◽  
Dependent Protein ◽  
Nuclear Levels ◽  
Activity Dependent

Class II histone deacetylases (HDACs) may decrease slow muscle fiber gene expression by repressing myogenic transcription factor myocyte enhancer factor 2 (MEF2). Here, we show that repetitive slow fiber type electrical stimulation, but not fast fiber type stimulation, caused HDAC4-GFP, but not HDAC5-GFP, to translocate from the nucleus to the cytoplasm in cultured adult skeletal muscle fibers. HDAC4-GFP translocation was blocked by calmodulin-dependent protein kinase (CaMK) inhibitor KN-62. Slow fiber type stimulation increased MEF2 transcriptional activity, nuclear Ca2+ concentration, and nuclear levels of activated CaMKII, but not total nuclear CaMKII or CaM-YFP. Thus, calcium transients for slow, but not fast, fiber stimulation patterns appear to provide sufficient Ca2+-dependent activation of nuclear CaMKII to result in net nuclear efflux of HDAC4. Nucleocytoplasmic shuttling of HDAC4-GFP in unstimulated resting fibers was not altered by KN-62, but was blocked by staurosporine, indicating that different kinases underlie nuclear efflux of HDAC4 in resting and stimulated muscle fibers.

scholarly journals Rescue of Dystrophic Skeletal Muscle by PGC-1α Involves a Fast to Slow Fiber Type Shift in the mdx Mouse

PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e30063 ◽  
Author(s):  
Joshua T. Selsby ◽  
Kevin J. Morine ◽  
Klara Pendrak ◽  
Elisabeth R. Barton ◽  
H. Lee Sweeney
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Mdx Mouse ◽  
Slow Fiber ◽  
Type Shift

Glucocorticoid sites in skeletal muscle: adrenalectomy, maturation, fiber type, and sex

1984 ◽  
Vol 247 (1) ◽  
pp. E118-E125 ◽  
Author(s):  
D. C. DuBois ◽  
R. R. Almon
Keyword(s):  
Skeletal Muscle ◽  
Extensor Digitorum Longus ◽  
Fiber Type ◽  
Cross Reactivity ◽  
Tissue Preparation ◽  
Stabilization Method ◽  
Exponential Decline ◽  
Longus Muscle ◽  
Slow Fiber ◽  
Fast Fiber

The glucocorticoid receptor population in skeletal muscle of the rat was examined. Data are included that address the following: tissue preparation, receptor stabilization, method of assay and analysis, cross-reactivity of a large variety of steroids, time to equilibrium, and the effect of adrenalectomy on the number of sites as well as the apparent binding affinity. In addition, we have observed the following: 1) an exponential decline in the concentration of sites from 27 to 160 days after birth; 2) a significantly higher concentration of sites in muscle from male animals as compared with female animals; and 3) a significantly higher concentration of sites in the slow-fiber soleus muscle as compared with the fast-fiber extensor digitorum longus muscle.

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