scholarly journals Progressive reorganization of mitochondrial apparatus in aging skeletal muscle of naked mole rats (Heterocephalus glaber) as revealed by electron microscopy: potential role in continual maintenance of muscle activity

Aging ◽  
2021 ◽  
Author(s):  
Valeriya Vays ◽  
Irina Vangely ◽  
Chupalav Eldarov ◽  
Susanne Holtze ◽  
Thomas Hildebrandt ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Muscle Activity ◽  
Potential Role ◽  
Heterocephalus Glaber

scholarly journals Identification of the MuRF1 skeletal muscle ubiquitylome through quantitative proteomics

Function ◽  
2021 ◽  
Author(s):  
Leslie M Baehr ◽  
David C Hughes ◽  
Sarah A Lynch ◽  
Delphi Van Haver ◽  
Teresa Mendes Maia ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Potential Role ◽  
Ubiquitin Proteasome System ◽  
In Vivo Electroporation ◽  
Adult Mice ◽  
Expression Of Genes ◽  
Regulation Of Metabolism ◽  
Ubiquitin Proteasome

Abstract MuRF1 (TRIM63) is a muscle-specific E3 ubiquitin ligase and component of the ubiquitin proteasome system. MuRF1 is transcriptionally upregulated under conditions that cause muscle loss, in both rodents and humans, and is a recognized marker of muscle atrophy. In this study, we used in vivo electroporation to determine if MuRF1 overexpression alone can cause muscle atrophy and, in combination with ubiquitin proteomics, identify the endogenous MuRF1 substrates in skeletal muscle. Overexpression of MuRF1 in adult mice increases ubiquitination of myofibrillar and sarcoplasmic proteins, increases expression of genes associated with neuromuscular junction instability, and causes muscle atrophy. A total of 169 ubiquitination sites on 56 proteins were found to be regulated by MuRF1. MuRF1-mediated ubiquitination targeted both thick and thin filament contractile proteins, as well as, glycolytic enzymes, deubiquitinases, p62, and VCP. These data reveal a potential role for MuRF1 in not only the breakdown of the sarcomere, but also the regulation of metabolism and other proteolytic pathways in skeletal muscle.

scholarly journals Toll-Like Receptors in Ischaemia and Its Potential Role in the Pathophysiology of Muscle Damage in Critical Limb Ischaemia

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Hemanshu Patel ◽  
Sidney G. Shaw ◽  
Xu Shi-Wen ◽  
David Abraham ◽  
Daryll M. Baker ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Damage ◽  
Potential Role ◽  
Arterial Disease ◽  
Severe Form ◽  
Tissue Loss ◽  
Critical Limb Ischaemia ◽  
Limb Ischaemia ◽  
Toll Like Receptors ◽  
Skeletal Muscle Damage

Toll-like receptors (TLRs) are key receptors of the innate immune system which are expressed on immune and nonimmune cells. They are activated by both pathogen-associated molecular patterns and endogenous ligands. Activation of TLRs culminates in the release of proinflammatory cytokines, chemokines, and apoptosis. Ischaemia and ischaemia/reperfusion (I/R) injury are associated with significant inflammation and tissue damage. There is emerging evidence to suggest that TLRs are involved in mediating ischaemia-induced damage in several organs. Critical limb ischaemia (CLI) is the most severe form of peripheral arterial disease (PAD) and is associated with skeletal muscle damage and tissue loss; however its pathophysiology is poorly understood. This paper will underline the evidence implicating TLRs in the pathophysiology of cerebral, renal, hepatic, myocardial, and skeletal muscle ischaemia and I/R injury and discuss preliminary data that alludes to the potential role of TLRs in the pathophysiology of skeletal muscle damage in CLI.

scholarly journals A potential role for Akt/FOXO signalling in both protein loss and the impairment of muscle carbohydrate oxidation during sepsis in rodent skeletal muscle

2008 ◽  
Vol 586 (22) ◽  
pp. 5589-5600 ◽  
Author(s):  
Hannah Crossland ◽  
Dumitru Constantin-Teodosiu ◽  
Sheila M. Gardiner ◽  
Despina Constantin ◽  
Paul L. Greenhaff
Keyword(s):  
Skeletal Muscle ◽  
Potential Role ◽  
Carbohydrate Oxidation ◽  
Protein Loss

scholarly journals Phenotypic Modulation of Skeletal Muscle Fibers in LPIN1-Deficient Lipodystrophic (fld) Mice

2018 ◽  
Vol 56 (2) ◽  
pp. 322-331
Author(s):  
Rani S. Sellers ◽  
S. Radma Mahmood ◽  
Geoffrey S. Perumal ◽  
Frank P. Macaluso ◽  
Irwin J. Kurland
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Fiber Type ◽  
Periodic Acid ◽  
Muscle Fibers ◽  
Myosin Atpase ◽  
Hybrid Fibers ◽  
Periodic Acid Schiff ◽  
Skeletal Muscle Fibers ◽  
Lipin 1

Lipin-1 ( Lpin1)–deficient lipodystrophic mice have scant and immature adipocytes and develop transient fatty liver early in life. Unlike normal mice, these mice cannot rely on stored triglycerides to generate adenosine triphosphate (ATP) from the β-oxidation of fatty acids during periods of fasting. To compensate, these mice store much higher amounts of glycogen in skeletal muscle and liver than wild-type mice in order to support energy needs during periods of fasting. Our studies demonstrated that there are phenotypic changes in skeletal muscle fibers that reflect an adaptation to this unique metabolic situation. The phenotype of skeletal muscle (soleus, gastrocnemius, plantaris, and extensor digitorum longus [EDL]) from Lpin1-/- was evaluated using various methods including immunohistochemistry for myosin heavy chains (Myh) 1, 2, 2a, 2b, and 2x; enzyme histochemistry for myosin ATPase, cytochrome-c oxidase (COX), and succinyl dehydrogenase (SDH); periodic acid–Schiff; and transmission electron microscopy. Fiber-type changes in the soleus muscle of Lpin1-/- mice were prominent and included decreased Myh1 expression with concomitant increases in Myh2 expression and myosin-ATPase activity; this change was associated with an increase in the presence of Myh1/2a or Myh1/2x hybrid fibers. Alterations in mitochondrial enzyme activity (COX and SDH) were apparent in the myofibers in the soleus, gastrocnemius, plantaris, and EDL muscles. Electron microscopy revealed increases in the subsarcolemmal mitochondrial mass in the muscles of Lpin1-/- mice. These data demonstrate that lipin-1 deficiency results in phenotypic fiber-specific modulation of skeletal muscle necessary for compensatory fuel utilization adaptations in lipodystrophy.

Evaluation of individual skeletal muscle activity by glucose uptake during pedaling exercise at different workloads using positron emission tomography

2009 ◽  
Vol 107 (2) ◽  
pp. 599-604 ◽  
Author(s):  
Yuichi Gondoh ◽  
Manabu Tashiro ◽  
Masatoshi Itoh ◽  
Mohammad M. Masud ◽  
Hiroomi Sensui ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Positron Emission Tomography ◽  
Glucose Uptake ◽  
Muscle Activity ◽  
Rectus Femoris ◽  
Emission Tomography ◽  
Whole Body ◽  
Control Subjects ◽  
Positron Emission ◽  
Iliacus Muscle

Skeletal muscle glucose uptake closely reflects muscle activity at exercise intensity levels <55% of maximal oxygen consumption (V̇o2max). Our purpose was to evaluate individual skeletal muscle activity from glucose uptake in humans during pedaling exercise at different workloads by using [18F]fluorodeoxyglucose (FDG) and positron emission tomography (PET). Twenty healthy male subjects were divided into two groups (7 exercise subjects and 13 control subjects). Exercise subjects were studied during 35 min of pedaling exercise at 40 and 55% V̇o2max exercise intensities. FDG was injected 10 min after the start of exercise or after 20 min of rest. PET scanning of the whole body was conducted after completion of the exercise or rest period. In exercise subjects, mean FDG uptake [standardized uptake ratio (SUR)] of the iliacus muscle and muscles of the anterior part of the thigh was significantly greater than uptake in muscles of control subjects. At 55% V̇o2max exercise, SURs of the iliacus muscle and thigh muscles, except for the rectus femoris, increased significantly compared with SURs at 40% V̇o2max exercise. Our results are the first to clarify that the iliacus muscle, as well as the muscles of the anterior thigh, is the prime muscle used during pedaling exercise. In addition, the iliacus muscle and all muscles in the thigh, except for the rectus femoris, contribute when the workload of the pedaling exercise increases from 40 to 55% V̇o2max.

Regulation of the Size and Distribution of Agrin-Induced Postsynaptic-like Apparatus in Adult Skeletal Muscle by Electrical Muscle Activity

1999 ◽  
Vol 13 (3) ◽  
pp. 207-217 ◽  
Author(s):  
Iacob Mathiesen ◽  
Mendell Rimer ◽  
Omid Ashtari ◽  
Ilana Cohen ◽  
Uel J. McMahan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Activity ◽  
Adult Skeletal Muscle ◽  
Electrical Muscle

scholarly journals Appendicular lean mass is lower in late compared with early perimenopausal women: potential role of FSH

2020 ◽  
Vol 128 (5) ◽  
pp. 1373-1380
Author(s):  
Young-Min Park ◽  
Catherine M. Jankowski ◽  
Cemal Ozemek ◽  
Kerry L. Hildreth ◽  
Wendy M. Kohrt ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Lean Mass ◽  
Potential Role ◽  
Appendicular Lean Mass ◽  
Vulnerable Period ◽  
Perimenopausal Women

Our data suggest that the late perimenopausal stage may be a vulnerable period for the loss of skeletal muscle, potentially related to elevations in FSH.

Effect of taxol on the interaction of tubulin with myosin filaments

1984 ◽  
Vol 62 (9) ◽  
pp. 878-884 ◽  
Author(s):  
Toshihiro Fujii ◽  
Tatsuo Suzuki ◽  
Akira Hachimori ◽  
Michiyo Fujii ◽  
Yoshiyuki Kondo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Atpase Activity ◽  
Cross Section ◽  
Molar Ratio ◽  
Tubulin Polymerization ◽  
Myosin Filaments ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Section Electron Microscopy

The interaction between polymerized tubulin from porcine brain and myosin from rabbit skeletal muscle was examined. The addition of myosin to the solution of tubulin polymerized by taxol resulted in a remarkable increase in turbidity within a few minutes at 37 °C, and a dense and stable precipitate was formed. The maximal molar ratio of tubulin bound to myosin was calculated to be about 4, while the value was about 2 when 6S tubulin was used. Both podophyllotoxin and colchicine suppressed the taxol-dependent increase of the binding of tubulin to myosin, but only when they were preincubated with tubulin prior to addition of taxol. 6S tubulin inhibited with aetin-activated Mg2+-ATPase activity of myosin, and polymerized tubulin inhibited the Mg-ATPase more than 6S tubulin. Dense precipitates of tubulin and myosin were observed by thin-section electron microscopy. Microtubules were observed to be entangled in myosin filaments and single microtubules were occasionally surrounded by five myosin filaments in a cross section, similar to actin–myosin arrays in muscle. After incubation of tubulin with myosin, taxol was able to induce tubulin polymerization in the same way as it polymerized microtubules in the absence of myosin.

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