Trophic Influen Ces of Neurogenic Substances on Adult Skeletal Muscles in Vivo

2020 ◽  
pp. 101-146
Author(s):  
Heather L. Davis
Keyword(s):  
Skeletal Muscles

scholarly journals SPEG binds with desmin and its deficiency causes defects in triad and focal adhesion proteins

2020 ◽  
Author(s):  
Shiyu Luo ◽  
Qifei Li ◽  
Jasmine Lin ◽  
Quinn Murphy ◽  
Isabelle Marty ◽  
...  
Keyword(s):  
Focal Adhesion ◽  
Skeletal Muscles ◽  
Striated Muscle ◽  
Calcium Handling ◽  
Intermediate Filament Protein ◽  
Β1 Integrin ◽  
Adhesion Proteins ◽  
Focal Adhesion Proteins ◽  
Early Endosomes

Abstract SPEG, a member of the myosin light chain kinase family, is localized at the level of triad surrounding myofibrils in skeletal muscles. In humans, SPEG mutations are associated with centronuclear myopathy and cardiomyopathy. Using a striated muscle specific Speg-knockout (KO) mouse model, we have previously shown that SPEG is critical for triad maintenance and calcium handling. Here we further examined the molecular function of SPEG and characterized the effects of SPEG deficiency on triad and focal adhesion proteins. We used yeast two-hybrid assay, and identified desmin, an intermediate filament protein, to interact with SPEG and confirmed this interaction by co-immunoprecipitation. Using domain-mapping assay, we defined that Ig-like and fibronectin III domains of SPEG interact with rod domain of desmin. In skeletal muscles, SPEG depletion leads to desmin aggregates in vivo and a shift in desmin equilibrium from soluble to insoluble fraction. We also profiled the expression and localization of triadic proteins in Speg-KO mice using western blot and immunofluorescence. The amounts of RyR1 and triadin were markedly reduced, whereas DHPRα1, SERCA1, and triadin were abnormally accumulated in discrete areas of Speg-KO myofibers. In addition, Speg-KO muscles exhibited internalized vinculin and β1 integrin, both of which are critical components of the focal adhesion complex. Further, β1 integrin was abnormally accumulated in early endosomes of Speg-KO myofibers. These results demonstrate that SPEG-deficient skeletal muscles exhibit several pathological features similar to those seen in MTM1 deficiency. Defects of shared cellular pathways may underlie these structural and functional abnormalities in both types of diseases.

scholarly journals Cryptochromes regulate IGF-1 production and signaling through control of JAK2-dependent STAT5B phosphorylation

2017 ◽  
Vol 28 (6) ◽  
pp. 834-842 ◽  
Author(s):  
Amol Chaudhari ◽  
Richa Gupta ◽  
Sonal Patel ◽  
Nikkhil Velingkaar ◽  
Roman Kondratov
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Skeletal Muscles ◽  
Cancer Metabolism ◽  
Reduced Body ◽  
Circadian Control ◽  
Cell Growth And Proliferation ◽  
Deficient Mice ◽  
Igf Signaling

Insulin-like growth factor (IGF) signaling plays an important role in cell growth and proliferation and is implicated in regulation of cancer, metabolism, and aging. Here we report that IGF-1 level in blood and IGF-1 signaling demonstrates circadian rhythms. Circadian control occurs through cryptochromes (CRYs)—transcriptional repressors and components of the circadian clock. IGF-1 rhythms are disrupted in Cry-deficient mice, and IGF-1 level is reduced by 80% in these mice, which leads to reduced IGF signaling. In agreement, Cry-deficient mice have reduced body (∼30% reduction) and organ size. Down-regulation of IGF-1 upon Cry deficiency correlates with reduced Igf-1 mRNA expression in the liver and skeletal muscles. Igf-1 transcription is regulated through growth hormone–induced, JAK2 kinase–mediated phosphorylation of transcriptional factor STAT5B. The phosphorylation of STAT5B on the JAK2-dependent Y699 site is significantly reduced in the liver and skeletal muscles of Cry-deficient mice. At the same time, phosphorylation of JAK2 kinase was not reduced upon Cry deficiency, which places CRY activity downstream from JAK2. Thus CRYs link the circadian clock and JAK-STAT signaling through control of STAT5B phosphorylation, which provides the mechanism for circadian rhythms in IGF signaling in vivo.

Acoustic Signals from Skeletal Muscle

Physiology ◽  
1990 ◽  
Vol 5 (1) ◽  
pp. 17-21 ◽  
Author(s):  
DT Barry
Keyword(s):  
Skeletal Muscles ◽  
Acoustic Signals ◽  
Skin Surface ◽  
Pressure Waves ◽  
Mechanical Vibrations ◽  
Intrinsic Component ◽  
Measuring Force ◽  
Muscle Sounds

Contracting skeletal muscles emit pressure waves that are audible at the skin surface and are easily recorded with standard microphones both in vivo and in vitro. These muscle sounds are an intrinsic component of the contractile mechanism and are produced by mechanical vibrations at the resonant frequency of the muscle. The sounds are useful in measuring force, fatigue, and mechanical properties of muscle.

Texture in Quantitative Viscoelastic Response (QVisR) Images Differentiates Dystrophic from Control Skeletal Muscles in Boys, In Vivo

2019 ◽  
Author(s):  
Christopher J. Moore ◽  
Melissa C. Caughey ◽  
Diane O. Meyer ◽  
Regina Emmett ◽  
Catherine Jacobs ◽  
...  
Keyword(s):  
Skeletal Muscles ◽  
Viscoelastic Response

IN VIVO ANDROGEN BINDING IN RAT SKELETAL AND PERINEAL MUSCLES

1979 ◽  
Vol 91 (2) ◽  
pp. 362-372 ◽  
Author(s):  
France T. Dionne ◽  
Jean Y. Dubé ◽  
Renée L. Lesage ◽  
Roland R. Tremblay
Keyword(s):  
Skeletal Muscles ◽  
Sucrose Gradient ◽  
Reductase Activity ◽  
High Rate ◽  
Ventral Prostate ◽  
Target Tissue ◽  
Thigh Muscles ◽  
Reference Target ◽  
Androgen Binding

ABSTRACT In vivo binding of [3H] testosterone2), [3H]5α-dihydrotestosterone and [3H]3α-androstanediol to cytosolic and nuclear fractions of LA/BC and thigh muscles has been studied in functionally hepatectomized castrated rats following a 1 h infusion of the labelled steroid. The identification of metabolites formed from each steroid has also been determined in tissue cytosols. In each experiment, ventral prostate was used as reference target tissue. After [3H] testosterone and [3H]5α-dihydrotestosterone perfusions, cytosolic binding could be demonstrated in a 8–10S peak on sucrose gradient with LA/BC and ventral prostate or in the macromolecular fraction after filtration through Sephadex G-25 with thigh muscles. In both types of muscles, [3H]5α-dihydrotestosterone binding represented only one tenth of [3H] testosterone binding. This behaviour seems to be related to the high rate of 5α-dihydrotestosterone metabolism observed in these tissues; testosterone, on the contrary, was not metabolized. After [3H]3α-androstanediol perfusion, cytosolic [3H] androgen binding in LA/BC and in thigh muscles was almost non-existent. In muscles [3H]3α-androstanediol remained essentially unconverted. In ventral prostate, with every hormone studied level of cytosolic binding was comparable. It was observed that in this tissue [3H] testosterone and [3H]3α-androstanediol were metabolized into [3H]5α-dihydrotestosterone. Androgen binding to 0.4 m KCl extracted nuclear proteins has been demonstrated in ventral prostate as a 3.5–4.5S binding peak on sucrose gradient and this with each steroid perfused. In LA/BC, only [3H] testosterone gave a well defined binding peak. In thigh muscles, levels of nuclear binding were too low to be determined. In summary, these results suggest that rat perineal and skeletal muscles possess cytosolic androgen binding proteins similar to those found in ventral prostate. However, it appears that steroid metabolism is quite different in ventral prostate and muscles with respect to presence of 5α-reductase activity and extent of conversion of 5α-dihydrotestosterone into androstanediols. These differences may explain why, in vivo, muscles bind testosterone instead of 5α-dihydrotestosterone as in ventral prostate.

scholarly journals Musclin is an activity-stimulated myokine that enhances physical endurance

2015 ◽  
Vol 112 (52) ◽  
pp. 16042-16047 ◽  
Author(s):  
Ekaterina Subbotina ◽  
Ana Sierra ◽  
Zhiyong Zhu ◽  
Zhan Gao ◽  
Siva Rama Krishna Koganti ◽  
...  
Keyword(s):  
Exercise Capacity ◽  
Exercise Tolerance ◽  
Skeletal Muscles ◽  
Molecular Mechanisms ◽  
Mitochondrial Protein ◽  
Guanosine Monophosphate ◽  
Physical Endurance ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Exercise remains the most effective way to promote physical and metabolic wellbeing, but molecular mechanisms underlying exercise tolerance and its plasticity are only partially understood. In this study we identify musclin—a peptide with high homology to natriuretic peptides (NP)—as an exercise-responsive myokine that acts to enhance exercise capacity in mice. We use human primary myoblast culture and in vivo murine models to establish that the activity-related production of musclin is driven by Ca2+-dependent activation of Akt1 and the release of musclin-encoding gene (Ostn) transcription from forkhead box O1 transcription factor inhibition. Disruption of Ostn and elimination of musclin secretion in mice results in reduced exercise tolerance that can be rescued by treatment with recombinant musclin. Reduced exercise capacity in mice with disrupted musclin signaling is associated with a trend toward lower levels of plasma atrial NP (ANP) and significantly smaller levels of cyclic guanosine monophosphate (cGMP) and peroxisome proliferator-activated receptor gamma coactivator 1-α in skeletal muscles after exposure to exercise. Furthermore, in agreement with the established musclin ability to interact with NP clearance receptors, but not with NP guanyl cyclase-coupled signaling receptors, we demonstrate that musclin enhances cGMP production in cultured myoblasts only when applied together with ANP. Elimination of the activity-related musclin-dependent boost of ANP/cGMP signaling results in significantly lower maximum aerobic capacity, mitochondrial protein content, respiratory complex protein expression, and succinate dehydrogenase activity in skeletal muscles. Together, these data indicate that musclin enhances physical endurance by promoting mitochondrial biogenesis.

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