Hindlimb Muscle Dissection, Permeabilization, and Respirometry v1

2021 ◽  
Author(s):  
Matthew D. Campbell ◽  
David J. Marcinek
Keyword(s):  
Skeletal Muscle ◽  
Muscle Biopsy ◽  
Mitochondrial Respiration ◽  
Gastrocnemius Muscle ◽  
Muscle Fibers ◽  
Mouse Muscle ◽  
Skeletal Muscle Biopsy ◽  
Cellular Environment ◽  
Permeabilized Muscle

The use of permeabilized muscle fibers (PMF) has emerged as a gold standard for assessing skeletal muscle mitochondrial function. PMF provide an intermediate approach between in vivo strategies and isolated mitochondria that allows the mitochondria to be maintained in close to their native morphology in the myofiber while allowing greater control of substrate and inhibitor concentrations. However, like mitochondrial isolation, the primary drawback to PMF is disruption of the cellular environment during the muscle biopsy and preparation. Despite all the benefits of permeabilized muscle fibers in evaluating mitochondrial respiration and dynamics one of the major drawbacks is increased variability introduced during a muscle biopsy as well as intrinsic variation that exists due to sex and age. This study was designed to evaluate how age, sex, and biopsy preparations affect mitochondrial respiration in extensor digitorum longus, soleus, and gastrocnemius muscle of mice. Here we detail a modified approach to skeletal muscle biopsy of the gastrocnemius muscle of mice focused on maintenance of intact fibers that results in greater overall respiration compared to cut fibers. The improved respiration of intact fibers is sex specific as are some of the changes in mitochondrial respiration with age. This study shows the need for standard practices when measuring mitochondrial respiration in permeabilized muscle and provides a protocol to control for variation introduced during a typical mouse muscle biopsy.

Heterogeneity of human adaptations to bed rest and hypoxia: a retrospective analysis within the skeletal muscle oxidative function

2021 ◽  
Author(s):  
Desy Salvadego ◽  
Bruno Grassi ◽  
Michail E. Keramidas ◽  
Ola Eiken ◽  
Adam C. McDonnell ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Respiration ◽  
Bed Rest ◽  
Knee Extension ◽  
Large Variability ◽  
The Individual ◽  
Oxidative Function ◽  
Knee Extension Exercise ◽  
Permeabilized Muscle

This retrospective study was designed to analyse the interindividual variability in the responses of different variables characterizing the skeletal muscle oxidative function to normoxic (N-BR) and hypoxic (H-BR) bed rests, and to a hypoxic ambulatory confinement (H-AMB) of 10 and 21 days. We also assessed whether and how the addition of hypoxia to bed rest might influence the heterogeneity of the responses. In vivo measurements of O2 uptake and muscle fractional O2 extraction were carried out during an incremental one-leg knee-extension exercise. Mitochondrial respiration was assessed in permeabilized muscle fibers. A total of 17 subjects were included in this analysis. This analysis revealed a similar variability among subjects in the alterations induced by N-BR and H-BR both in peak O2 uptake (SD: 4.1 and 3.3% after 10 days; 4.5 and 8.1% after 21 days, respectively) and peak muscle fractional O2 extraction (SD: 5.9 and 7.3% after 10 days; 6.5 and 7.3% after 21 days), independently from the duration of the exposure. The individual changes measured in these variables were significantly related (r=0.66, P=0.004 after N-BR; r=0.61, P=0.009 after H-BR). Mitochondrial respiration showed a large variability of response after both N-BR (SD: 25.0 and 15.7% after 10 and 21 days) and H-BR (SD: 13.0 and 19.8% after 10 and 21 days), no correlation was found between N-BR and H-BR changes. When added to bed rest, hypoxia altered the individual adaptations within the mitochondria but not those intrinsic to the muscle oxidative function in vivo, both after short and medium-term exposures.

scholarly journals A comparative study of mitochondrial respiration in circulating blood cells and skeletal muscle fibers in women

2019 ◽  
Vol 317 (3) ◽  
pp. E503-E512 ◽  
Author(s):  
Shannon Rose ◽  
Eugenia Carvalho ◽  
Eva C. Diaz ◽  
Matthew Cotter ◽  
Sirish C. Bennuri ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Blood Cells ◽  
Muscle Fibers ◽  
Circulating Cells ◽  
Permeabilized Muscle

Skeletal muscle mitochondrial respiration is thought to be altered in obesity, insulin resistance, and type 2 diabetes; however, the invasive nature of tissue biopsies is an important limiting factor for studying mitochondrial function. Recent findings suggest that bioenergetics profiling of circulating cells may inform on mitochondrial function in other tissues in lieu of biopsies. Thus, we sought to determine whether mitochondrial respiration in circulating cells [peripheral blood mononuclear cells (PBMCs) and platelets] reflects that of skeletal muscle fibers derived from the same subjects. PBMCs, platelets, and skeletal muscle (vastus lateralis) samples were obtained from 32 young (25–35 yr) women of varying body mass indexes. With the use of extracellular flux analysis and high-resolution respirometry, mitochondrial respiration was measured in intact blood cells as well as in permeabilized cells and permeabilized muscle fibers. Respiratory parameters were not correlated between permeabilized muscle fibers and intact PBMCs or platelets. In a subset of samples ( n = 12–13) with permeabilized blood cells available, raw measures of substrate (pyruvate, malate, glutamate, and succinate)-driven respiration did not correlate between permeabilized muscle (per mg tissue) and permeabilized PBMCs (per 106 cells); however, complex I leak and oxidative phosphorylation coupling efficiency correlated between permeabilized platelets and muscle (Spearman’s ρ = 0.64, P = 0.030; Spearman’s ρ = 0.72, P = 0.010, respectively). Our data indicate that bioenergetics phenotypes in circulating cells cannot recapitulate muscle mitochondrial function. Select circulating cell bioenergetics phenotypes may possibly inform on overall metabolic health, but this postulate awaits validation in cohorts spanning a larger range of insulin resistance and type 2 diabetes status.

Internalized capillaries in skeletal muscle biopsy

2015 ◽  
Vol 25 (1) ◽  
pp. 94-95
Author(s):  
Andreas Hawlik ◽  
Anette Wassner ◽  
Albert C. Ludolph ◽  
Jan Lewerenz ◽  
Angela Rosenbohm
Keyword(s):  
Skeletal Muscle ◽  
Muscle Biopsy ◽  
Skeletal Muscle Biopsy

Rapid and reciprocal regulation of tenascin-C and tenascin-Y expression by loading of skeletal muscle

2000 ◽  
Vol 113 (20) ◽  
pp. 3583-3591 ◽  
Author(s):  
M. Fluck ◽  
V. Tunc-Civelek ◽  
M. Chiquet
Keyword(s):  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Tensile Stress ◽  
Muscle Fibers ◽  
Myotendinous Junction ◽  
Left Wing ◽  
C Protein ◽  
Tenascin C ◽  
Mrna Induction

Tenascin-C and tenascin-Y are two structurally related extracellular matrix glycoproteins that in many tissues show a complementary expression pattern. Tenascin-C and the fibril-associated minor collagen XII are expressed in tissues bearing high tensile stress and are located in normal skeletal muscle, predominantly at the myotendinous junction that links muscle fibers to tendon. In contrast, tenascin-Y is strongly expressed in the endomysium surrounding single myofibers, and in the perimysial sheath around fiber bundles. We previously showed that tenascin-C and collagen XII expression in primary fibroblasts is regulated by changes in tensile stress. Here we have tested the hypothesis that the expression of tenascin-C, tenascin-Y and collagen XII in skeletal muscle connective tissue is differentially modulated by mechanical stress in vivo. Chicken anterior latissimus dorsi muscle (ALD) was mechanically stressed by applying a load to the left wing. Within 36 hours of loading, expression of tenascin-C protein was ectopically induced in the endomysium along the surface of single muscle fibers throughout the ALD, whereas tenascin-Y protein expression was barely affected. Expression of tenascin-C protein stayed elevated after 7 days of loading whereas tenascin-Y protein was reduced. Northern blot analysis revealed that tenascin-C mRNA was induced in ALD within 4 hours of loading while tenascin-Y mRNA was reduced within the same period. In situ hybridization indicated that tenascin-C mRNA induction after 4 hours of loading was uniform throughout the ALD muscle in endomysial fibroblasts. In contrast, the level of tenascin-Y mRNA expression in endomysium appeared reduced within 4 hours of loading. Tenascin-C mRNA and protein induction after 4–10 hours of loading did not correlate with signs of macrophage infiltration. Tenascin-C protein decreased again with removal of the load and nearly disappeared after 5 days. Furthermore, loading was also found to induce expression of collagen XII mRNA and protein, but to a markedly lower level, with slower kinetics and only partial reversibility. The results suggest that mechanical loading directly and reciprocally controls the expression of extracellular matrix proteins of the tenascin family in skeletal muscle.

scholarly journals PEDF-derived peptide promotes skeletal muscle regeneration through its mitogenic effect on muscle progenitor cells

2015 ◽  
Vol 309 (3) ◽  
pp. C159-C168 ◽  
Author(s):  
Tsung-Chuan Ho ◽  
Yi-Pin Chiang ◽  
Chih-Kuang Chuang ◽  
Show-Li Chen ◽  
Jui-Wen Hsieh ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cell Proliferation ◽  
Cyclin D1 ◽  
Satellite Cell ◽  
Muscle Regeneration ◽  
Muscle Fibers ◽  
Skeletal Muscle Regeneration ◽  
Satellite Cell Proliferation

In response injury, intrinsic repair mechanisms are activated in skeletal muscle to replace the damaged muscle fibers with new muscle fibers. The regeneration process starts with the proliferation of satellite cells to give rise to myoblasts, which subsequently differentiate terminally into myofibers. Here, we investigated the promotion effect of pigment epithelial-derived factor (PEDF) on muscle regeneration. We report that PEDF and a synthetic PEDF-derived short peptide (PSP; residues Ser93-Leu112) induce satellite cell proliferation in vitro and promote muscle regeneration in vivo. Extensively, soleus muscle necrosis was induced in rats by bupivacaine, and an injectable alginate gel was used to release the PSP in the injured muscle. PSP delivery was found to stimulate satellite cell proliferation in damaged muscle and enhance the growth of regenerating myofibers, with complete regeneration of normal muscle mass by 2 wk. In cell culture, PEDF/PSP stimulated C2C12 myoblast proliferation, together with a rise in cyclin D1 expression. PEDF induced the phosphorylation of ERK1/2, Akt, and STAT3 in C2C12 myoblasts. Blocking the activity of ERK, Akt, or STAT3 with pharmacological inhibitors attenuated the effects of PEDF/PSP on the induction of C2C12 cell proliferation and cyclin D1 expression. Moreover, 5-bromo-2′-deoxyuridine pulse-labeling demonstrated that PEDF/PSP stimulated primary rat satellite cell proliferation in myofibers in vitro. In summary, we report for the first time that PSP is capable of promoting the regeneration of skeletal muscle. The signaling mechanism involves the ERK, AKT, and STAT3 pathways. These results show the potential utility of this PEDF peptide for muscle regeneration.

scholarly journals Defective Acetylcholine Receptor Subunit Switch Precedes Atrophy of Slow-Twitch Skeletal Muscle Fibers Lacking ERK1/2 Kinases in Soleus Muscle

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Shuo Wang ◽  
Bonnie Seaberg ◽  
Ximena Paez-Colasante ◽  
Mendell Rimer
Keyword(s):  
Skeletal Muscle ◽  
Acetylcholine Receptor ◽  
Soleus Muscle ◽  
Muscle Fibers ◽  
Neuromuscular Synapse ◽  
Fiber Morphology ◽  
Skeletal Muscle Fibers ◽  
Slow Twitch

Abstract To test the role of extracellular-signal regulated kinases 1 and 2 (ERK1/2) in slow-twitch, type 1 skeletal muscle fibers, we studied the soleus muscle in mice genetically deficient for myofiber ERK1/2. Young adult mutant soleus was drastically wasted, with highly atrophied type 1 fibers, denervation at most synaptic sites, induction of “fetal” acetylcholine receptor gamma subunit (AChRγ), reduction of “adult” AChRε, and impaired mitochondrial biogenesis and function. In weanlings, fiber morphology and mitochondrial markers were mostly normal, yet AChRγ upregulation and AChRε downregulation were observed. Synaptic sites with fetal AChRs in weanling muscle were ~3% in control and ~40% in mutants, with most of the latter on type 1 fibers. These results suggest that: (1) ERK1/2 are critical for slow-twitch fiber growth; (2) a defective γ/ε-AChR subunit switch, preferentially at synapses on slow fibers, precedes wasting of mutant soleus; (3) denervation is likely to drive this wasting, and (4) the neuromuscular synapse is a primary subcellular target for muscle ERK1/2 function in vivo.

Overlapping functions of the myogenic bHLH genes MRF4 and MyoD revealed in double mutant mice

Development ◽  
1998 ◽  
Vol 125 (13) ◽  
pp. 2349-2358 ◽  
Author(s):  
A. Rawls ◽  
M.R. Valdez ◽  
W. Zhang ◽  
J. Richardson ◽  
W.H. Klein ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Double Mutant ◽  
Muscle Development ◽  
Expression Patterns ◽  
Muscle Fibers ◽  
Mutant Mice ◽  
Myoblast Differentiation ◽  
Bhlh Genes ◽  
Bhlh Factors

The myogenic basic helix-loop-helix (bHLH) genes - MyoD, Myf5, myogenin and MRF4 - exhibit distinct, but overlapping expression patterns during development of the skeletal muscle lineage and loss-of-function mutations in these genes result in different effects on muscle development. MyoD and Myf5 have been shown to act early in the myogenic lineage to establish myoblast identity, whereas myogenin acts later to control myoblast differentiation. In mice lacking myogenin, there is a severe deficiency of skeletal muscle, but some residual muscle fibers are present in mutant mice at birth. Mice lacking MRF4 are viable and have skeletal muscle, but they upregulate myogenin expression, which could potentially compensate for the absence of MRF4. Previous studies in which Myf5 and MRF4 null mutations were combined suggested that these genes do not share overlapping myogenic functions in vivo. To determine whether the functions of MRF4 might overlap with those of myogenin or MyoD, we generated double mutant mice lacking MRF4 and either myogenin or MyoD. MRF4/myogenin double mutant mice contained a comparable number of residual muscle fibers to mice lacking myogenin alone and myoblasts from those double mutant mice formed differentiated multinucleated myotubes in vitro as efficiently as wild-type myoblasts, indicating that neither myogenin nor MRF4 is absolutely essential for myoblast differentiation. Whereas mice lacking either MRF4 or MyoD were viable and did not show defects in muscle development, MRF4/MyoD double mutants displayed a severe muscle deficiency similar to that in myogenin mutants. Myogenin was expressed in MRF4/MyoD double mutants, indicating that myogenin is insufficient to support normal myogenesis in vivo. These results reveal unanticipated compensatory roles for MRF4 and MyoD in the muscle differentiation pathway and suggest that a threshold level of myogenic bHLH factors is required to activate muscle structural genes, with this level normally being achieved by combinations of multiple myogenic bHLH factors.

STIMULATION OF RAT SKELETAL MUSCLE ANGIOGENESIS BY DIRECT AND CELL-MEDIATED ADMINISTRATION OF RECOMBINANT ANGIOGENIN GENE

2020 ◽  
pp. 35-40
Author(s):  
И. В. Саматошенков
Keyword(s):  
Skeletal Muscle ◽  
Gastrocnemius Muscle ◽  
Mononuclear Cells ◽  
Muscle Fibers ◽  
Control Group ◽  
Human Umbilical Cord Blood ◽  
Human Umbilical Cord ◽  
Ischemic Area ◽  
Serotype 5 ◽  
Genetic Constructs

Цель - оценить эффективность реваскуляризации икроножной мышцы крысы в условиях прямой и опосредованной мононуклеарными клетками крови пуповины человека (МККП) доставки в область ишемии рекомбинантного гена ангиогенина (Ang) человека при помощи аденовирусного вектора 5-го серотипа (Ad5). Материал и методы. Исследования проведены на 30 крысах линии Wistar. Через 14 сут после иссечения фрагмента бедренной артерии животным инъецировали в ишемизированную икроножную мышцу генетическую конструкцию (группа Ad5-Ang, n=15). Крысам другой группы (МККП+Ad5-Ang, n=15) в тот же срок трансген доставляли в мышцу при помощи МККП. В группе контроля животным (n=15) вводили в мышцу 0,9 % NaCl в тех же условиях. Через 14 и 28 сут в области ишемии оценивали отношение капилляры/мышечные волокна, количество мышечных волокон и количество мышечных волокон с центральным расположением ядер (МЦЯ). Капилляры идентифицировали по локализации эндотелиальных клеток, выявляемых при помощи иммуногистохимической реакции с антителами против CD31. Результаты. На 14-е сутки после введения МККП+Ad5-Ang показатель отношения количества капилляров к количеству мышечных волокон в области ишемии увеличивается на 57 % (p<0,05). На 28-е сутки в группе МККП+Ad5-Ang и в группе Ad5-Ang значимые различия по данному показателю при сравнении с контрольной группой не выявлены. Количество мышечных волокон на 14-е сутки в группе Ad5-Ang не изменяется, а в группе МККП+Ad5-Ang - уменьшается на 58,4 % (p<0,05). К 28-м суткам этот показатель в группе МККП+Ad5-Ang уменьшается на 95,9 % (p<0,05), а в группе Ad5-Ang - на 197,8 % (p<0,05). Количество МЦЯ существенно увеличивается в обеих экспериментальных группах с применением генетических конструкций на 14-е сутки. Выводы. Введение рекомбинантного гена Ang в область ишемии скелетной мышцы или его доставка в эту область при помощи мононуклеарных клеток крови пуповины стимулирует ангиогенез и постишемическую регенерацию мышечных волокон. Objective - to evaluate the effectiveness of revascularization of the rat gastrocnemius muscle following direct and human umbilical cord blood mononuclear cells (MNCs)-mediated delivery of human recombinant angiogenin (Ang) gene to the ischemic area using adenovirus serotype 5 vector (Ad5). Materials and methods. The study was carried out on 30 Wistar rats. Fourteen days after the excision of the femoral artery fragment, the genetic construct was injected into the animals’ ischemic gastrocnemius muscle (AD5-Ang group, n=15). In the other group (mccp+Ad5-Ang, n=15), the transgene was delivered to the muscle with the help of MNCs within the same time limit. In the control group (n=15) 0,9 % NaCl was injected into the muscle of animals under the same conditions. Fourteen and twenty-eight days after the injection, the ratio of capillaries/muscle fibers, the number of muscle fibers and the number of muscle fibers with a central location of nuclei (MCN) were evaluated in the ischemic area. Capillaries were identified by localization of endothelial cells detected by immunohistochemical reaction with antibodies against CD31. Results. On the 14th day after administration of MNCs+Ad5Ang, the ratio of capillaries to the number of muscle fibers in the ischemic area increased by 57 % (p<0,05). On the 28th day in the MNCs+Ad5-Ang group and in the Ad5-Ang group, no significant differences in this indicator were found compared with the control group. The number of muscle fibers on the 14 day in the Ad5-Ang group did not change, and in the MNCs+Ad5-Ang group, it decreased by 58,4 % (p<0,05). By the 28th day, this indicator in the MNCs+Ad5-Ang group decreased by 95,9 % (p<0,05), and in the Ad5-Ang group - by 197,8 % (p<0,05). The number of MCN on the 14 day significantly increased in both experimental groups, in which the genetic constructs were used. Conclusion. The introduction of recombinant ang gene into the area of skeletal muscle ischemia or its delivery to this area with the help of MCNs stimulates angiogenesis and post-ischemic regeneration of muscle fibers.

scholarly journals An AMPK/Axin1-Rac1 signaling pathway mediates contraction-regulated glucose uptake in skeletal muscle cells

2020 ◽  
Vol 318 (3) ◽  
pp. E330-E342 ◽  
Author(s):  
Yingying Yue ◽  
Chang Zhang ◽  
Xuejiao Zhang ◽  
Shitian Zhang ◽  
Qian Liu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Signaling Pathway ◽  
Gastrocnemius Muscle ◽  
C2c12 Myotubes ◽  
Dependent Manner ◽  
Mouse Muscle ◽  
Protein Levels ◽  
Compound C ◽  
Skeletal Muscle Glucose Uptake

Contraction stimulates skeletal muscle glucose uptake predominantly through activation of AMP-activated protein kinase (AMPK) and Rac1. However, the molecular details of how contraction activates these signaling proteins are not clear. Recently, Axin1 has been shown to form a complex with AMPK and liver kinase B1 during glucose starvation-dependent activation of AMPK. Here, we demonstrate that electrical pulse-stimulated (EPS) contraction of C2C12 myotubes or treadmill exercise of C57BL/6 mice enhanced reciprocal coimmunoprecipitation of Axin1 and AMPK from myotube lysates or gastrocnemius muscle tissue. Interestingly, EPS or exercise upregulated total cellular Axin1 levels in an AMPK-dependent manner in C2C12 myotubes and gastrocnemius mouse muscle, respectively. Also, direct activation of AMPK with 5-aminoimidazole-4-carboxamide ribonucleotide treatment of C2C12 myotubes or gastrocnemius muscle elevated Axin1 protein levels. On the other hand, siRNA-mediated Axin1 knockdown lessened activation of AMPK in contracted myotubes. Further, AMPK inhibition with compound C or siRNA-mediated knockdown of AMPK or Axin1 blocked contraction-induced GTP loading of Rac1, p21-activated kinase phosphorylation, and contraction-stimulated glucose uptake. In summary, our results suggest that an AMPK/Axin1-Rac1 signaling pathway mediates contraction-stimulated skeletal muscle glucose uptake.

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