scholarly journals Effects of aging, exercise, and disease on force transfer in skeletal muscle

2015 ◽  
Vol 309 (1) ◽  
pp. E1-E10 ◽  
Author(s):  
David C. Hughes ◽  
Marita A. Wallace ◽  
Keith Baar
Keyword(s):  
Skeletal Muscle ◽  
Muscle Protein ◽  
Injury Rate ◽  
Cytoskeletal Proteins ◽  
Neural Activation ◽  
Force Transmission ◽  
Cross Sectional ◽  
Force Transfer ◽  
Effects Of Aging ◽  
And Function

The loss of muscle strength and increased injury rate in aging skeletal muscle has previously been attributed to loss of muscle protein (cross-sectional area) and/or decreased neural activation. However, it is becoming clear that force transfer within and between fibers plays a significant role in this process as well. Force transfer involves a secondary matrix of proteins that align and transmit the force produced by the thick and thin filaments along muscle fibers and out to the extracellular matrix. These specialized networks of cytoskeletal proteins aid in passing force through the muscle and also serve to protect individual fibers from injury. This review discusses the cytoskeleton proteins that have been identified as playing a role in muscle force transmission, both longitudinally and laterally, and where possible highlights how disease, aging, and exercise influence the expression and function of these proteins.

scholarly journals Effects of long-term intradialytic oral nutrition and exercise on muscle protein homeostasis and markers of mitochondrial content in patients on hemodialysis

2020 ◽  
Vol 319 (5) ◽  
pp. F885-F894
Author(s):  
Jorge L. Gamboa ◽  
Serpil Muge Deger ◽  
Bradley W. Perkins ◽  
Cindy Mambungu ◽  
Feng Sha ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Nutritional Supplementation ◽  
Sectional Area ◽  
Mitochondrial Content ◽  
Protein Energy Wasting ◽  
Cross Sectional ◽  
Protein Energy

Patients with end-stage kidney disease on maintenance hemodialysis commonly develop protein-energy wasting, a syndrome characterized by nutritional and metabolic abnormalities. Nutritional supplementation and exercise are recommended to prevent protein-energy wasting. In a 6-mo prospective randomized, open-label, clinical trial, we reported that the combination of resistance exercise and nutritional supplementation does not have an additive effect on lean body mass measured by dual-energy X-ray absorptiometry. To provide more mechanistic data, we performed a secondary analysis where we hypothesized that the combination of nutritional supplementation and resistance exercise would have additive effects on muscle protein accretion by stable isotope protein kinetic experiments, muscle mass by MRI, and mitochondrial content markers in muscle. We found that 6 mo of nutritional supplementation during hemodialysis increased muscle protein net balance [baseline: 2.5 (−17.8, 13.0) µg·100 mL−1·min−1 vs. 6 mo: 43.7 (13.0, 98.5) µg·100 mL−1·min−1, median (interquartile range), P = 0.04] and mid-thigh fat area [baseline: 162.3 (104.7, 226.6) cm2 vs. 6 mo: 181.9 (126.3, 279.2) cm2, median (interquartile range), P = 0.04]. Three months of nutritional supplementation also increased markers of mitochondrial content in muscle. Although the study is underpowered to detected differences, the combination of nutritional supplementation and exercise failed to show further benefit in protein accretion or muscle cross-sectional area. We conclude that long-term nutritional supplementation increases the skeletal muscle anabolic effect, the fat cross-sectional area of the thigh, and markers of mitochondrial content in skeletal muscle.

scholarly journals Myosin Heavy Chains IIa and IId Are Functionally Distinct in the Mouse

1998 ◽  
Vol 141 (4) ◽  
pp. 943-953 ◽  
Author(s):  
Carol A. Sartorius ◽  
Brian D. Lu ◽  
Leslie Acakpo-Satchivi ◽  
Renee P. Jacobsen ◽  
William C. Byrnes ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid Level ◽  
Spinal Curvature ◽  
Developmental Expression ◽  
Cross Sectional ◽  
Fast Myosin ◽  
Fast Myosin Heavy Chain ◽  
Fiber Number ◽  
Murine Skeletal Muscle ◽  
And Function

Myosin in adult murine skeletal muscle is composed primarily of three adult fast myosin heavy chain (MyHC) isoforms. These isoforms, MyHC-IIa, -IId, and -IIb, are >93% identical at the amino acid level and are broadly expressed in numerous muscles, and their genes are tightly linked. Mice with a null mutation in the MyHC-IId gene have phenotypes that include growth inhibition, muscle weakness, histological abnormalities, kyphosis (spinal curvature), and aberrant kinetics of muscle contraction and relaxation. Despite the lack of MyHC-IId, IId null mice have normal amounts of myosin in their muscles because of compensation by the MyHC-IIa gene. In each muscle examined from IId null mice, there was an increase in MyHC-IIa– containing fibers. MyHC-IIb content was unaffected in all muscles except the masseter, where its expression was extinguished in the IId null mice. Cross-sectional fiber areas, total muscle cross-sectional area, and total fiber number were affected in ways particular to each muscle. Developmental expression of adult MyHC genes remained unchanged in IId null mice. Despite this universal compensation of MyHC-IIa expression, IId null mice have severe phenotypes. We conclude that despite the similarity in sequence, MyHC-IIa and -IId have unique roles in the development and function of skeletal muscle.

Protein Metabolism and Age: Influence of Insulin and Resistance Exercise

2001 ◽  
Vol 11 (s1) ◽  
pp. S150-S163 ◽  
Author(s):  
Peter A. Farrell
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Mrna Translation ◽  
Bed Rest ◽  
Skeletal Muscle Protein ◽  
Amino Acid Availability ◽  
Effects Of Aging

Skeletal muscle proteins are constantly being synthesized and degraded, and the net balance between synthesis and degradation determines the resultant muscle mass. Biochemical pathways that control protein synthesis are complex, and the following must be considered: gene transcription, mRNA splicing, and transport to the cytoplasm; specific amino acyl-tRNA, messenger (mRNA), ribosomal (rRNA) availability; amino acid availability within the cell; the hormonal milieu; rates of mRNA translation; packaging in vesicles for some types of proteins; and post-translational processing such as glycation and phosphorylation/dephosphorylation. Each of these processes is responsive to the need for greater or lesser production of new proteins, and many states such as sepsis, uncontrolled diabetes, prolonged bed-rest, aging, chronic alcohol treatment, and starvation cause marked reductions in rates of skeletal muscle protein synthesis. In contrast, acute and chronic resistance exercise cause elevations in rates of muscle protein synthesis above rates found in nondiseased rested organisms, which are normally fed. Resistance exercise may be unique in this capacity. This chapter focuses on studies that have used exercise to elucidate mechanisms that explain elevations in rates of protein synthesis. Very few studies have investigated the effects of aging on these mechanisms; however, the literature that is available is reviewed.

scholarly journals Overload-mediated skeletal muscle hypertrophy is not impaired by loss of myofiber STAT3

2017 ◽  
Vol 313 (3) ◽  
pp. C257-C261 ◽  
Author(s):  
Joaquín Pérez-Schindler ◽  
Mary C. Esparza ◽  
James McKendry ◽  
Leigh Breen ◽  
Andrew Philp ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Signal Pathways ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Adaptive Growth ◽  
Stat3 Phosphorylation ◽  
Transcription 3

Although the signal pathways mediating muscle protein synthesis and degradation are well characterized, the transcriptional processes modulating skeletal muscle mass and adaptive growth are poorly understood. Recently, studies in mouse models of muscle wasting or acutely exercised human muscle have suggested a potential role for the transcription factor signal transducer and activator of transcription 3 (STAT3), in adaptive growth. Hence, in the present study we sought to define the contribution of STAT3 to skeletal muscle adaptive growth. In contrast to previous work, two different resistance exercise protocols did not change STAT3 phosphorylation in human skeletal muscle. To directly address the role of STAT3 in load-induced (i.e., adaptive) growth, we studied the anabolic effects of 14 days of synergist ablation (SA) in skeletal muscle-specific STAT3 knockout (mKO) mice and their floxed, wild-type (WT) littermates. Plantaris muscle weight and fiber area in the nonoperated leg (control; CON) was comparable between genotypes. As expected, SA significantly increased plantaris weight, muscle fiber cross-sectional area, and anabolic signaling in WT mice, although interestingly, this induction was not impaired in STAT3 mKO mice. Collectively, these data demonstrate that STAT3 is not required for overload-mediated hypertrophy in mouse skeletal muscle.

Protein catabolism and impairment of skeletal muscle insulin signalling in heart failure

2010 ◽  
Vol 119 (11) ◽  
pp. 465-466 ◽  
Author(s):  
P. Christian Schulze
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Muscle Protein ◽  
Insulin Signalling ◽  
Muscle Metabolism ◽  
Exercise Intolerance ◽  
Skeletal Muscle Protein ◽  
Glucose And Lipid Metabolism ◽  
Muscle Protein Metabolism ◽  
And Function

Derangements in systemic and local metabolism develop in patients with CHF [chronic HF (heart failure)] and contribute to the progression of the disease. Impaired skeletal muscle metabolism, morphology and function leading to exercise intolerance are hallmarks of the syndrome of CHF. These changes result in abnormal glucose and lipid metabolism, and the associated insulin resistance, which contribute to progression of skeletal muscle catabolism and development of muscle atrophy in patients with advanced HF. In the present issue of Clinical Science, Toth and co-workers demonstrate the impairment of skeletal muscle protein metabolism in patients with HF, and specifically show an impaired anabolic response in the skeletal muscle of these patients following a period of nutritional deficiency.

scholarly journals Cytoskeleton and Adhesion in Myogenesis

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Manoel Luís Costa
Keyword(s):  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Muscle Function ◽  
Force Production ◽  
Structure And Function ◽  
Cytoskeletal Proteins ◽  
Skeletal Muscle Differentiation ◽  
And Function ◽  
Structural Adaptations

The function of muscle is to contract, which means to exert force on a substrate. The adaptations required for skeletal muscle differentiation, from a prototypic cell, involve specialization of housekeeping cytoskeletal contracting and supporting systems into crystalline arrays of proteins. Here I discuss the changes that all three cytoskeletal systems (microfilaments, intermediate filaments, and microtubules) undergo through myogenesis. I also discuss their interaction, through the membrane, to extracellular matrix and to other cells, where force will be exerted during contraction. The three cytoskeletal systems are necessary for the muscle cell and must exert complementary roles in the cell. Muscle is a responsive system, where structure and function are integrated: the structural adaptations it undergoes depend on force production. In this way, the muscle cytoskeleton is a portrait of its physiology. I review the cytoskeletal proteins and structures involved in muscle function and focus particularly on their role in myogenesis, the process by which this incredible muscle machine is made. Although the focus is on skeletal muscle, some of the discussion is applicable to cardiac and smooth muscle.

scholarly journals Beneficial Effects of Resveratrol in Mouse Gastrocnemius: A Hint to Muscle Phenotype and Proteolysis

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2436
Author(s):  
Laura Mañas-García ◽  
Charlotte Denhard ◽  
Javier Mateu ◽  
Xavier Duran ◽  
Joaquim Gea ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Muscle Fiber ◽  
Troponin I ◽  
Muscle Protein ◽  
Strength Loss ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Therapeutic Implications ◽  
Resveratrol Treatment ◽  
And Function

We hypothesized that the phenolic compound resveratrol mitigates muscle protein degradation and loss and improves muscle fiber cross-sectional area (CSA) in gastrocnemius of mice exposed to unloading (7dI). In gastrocnemius of mice (female C57BL/6J, 10 weeks) exposed to a seven-day period of hindlimb immobilization with/without resveratrol treatment, markers of muscle proteolysis (tyrosine release, systemic troponin-I), atrophy signaling pathways, and muscle phenotypic features and function were analyzed. In gastrocnemius of unloaded mice treated with resveratrol, body and muscle weight and function were attenuated, whereas muscle proteolysis (tyrosine release), proteolytic and apoptotic markers, atrophy signaling pathways, and myofiber CSA significantly improved. Resveratrol treatment of mice exposed to a seven-day period of unloading prevented body and muscle weight and limb strength loss, while an improvement in muscle proteolysis, proteolytic markers, atrophy signaling pathways, apoptosis, and muscle fiber CSA was observed in the gastrocnemius muscle. These findings may have potential therapeutic implications in the management of disuse muscle atrophy in clinical settings.

scholarly journals Mitochondrial dysfunction and insulin resistance from the outside in: extracellular matrix, the cytoskeleton, and mitochondria

2011 ◽  
Vol 301 (5) ◽  
pp. E749-E755 ◽  
Author(s):  
Dawn K. Coletta ◽  
Lawrence J. Mandarino
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Contractile Activity ◽  
Cytoskeletal Proteins ◽  
Altered Expression ◽  
Insulin Resistant ◽  
And Function

Insulin resistance in skeletal muscle is a prominent feature of obesity and type 2 diabetes. The association between mitochondrial changes and insulin resistance is well known. More recently, there is growing evidence of a relationship between inflammation, extracellular remodeling, and insulin resistance. The intent of this review is to propose a potentially novel mechanism for the development of insulin resistance, focusing on the underappreciated connections among inflammation, extracellular remodeling, cytoskeletal interactions, mitochondrial function, and insulin resistance in human skeletal muscle. Several sources of inflammation, including expansion of adipose tissue resulting in increased lipolysis and alterations in pro- and anti-inflammatory cytokines, contribute to the insulin resistance observed in obesity and type 2 diabetes. In the experimental model of lipid oversupply, an inflammatory response in skeletal muscle leads to altered expression extracellular matrix-related genes as well as nuclear encoded mitochondrial genes. A similar pattern also is observed in “naturally” occurring insulin resistance in muscle of obese nondiabetic individuals and patients with type 2 diabetes mellitus. More recently, alterations in proteins (including α-actinin-2, desmin, proteasomes, and chaperones) involved in muscle structure and function have been observed in insulin-resistant muscle. Some of these cytoskeletal proteins are mechanosignal transducers that allow muscle fibers to sense contractile activity and respond appropriately. The ensuing alterations in expression of genes coding for mitochondrial proteins and cytoskeletal proteins may contribute to the mitochondrial changes observed in insulin-resistant muscle. These changes in turn may lead to a reduction in fat oxidation and an increase in intramyocellular lipid, which contributes to the defects in insulin signaling in insulin resistance.

scholarly journals Mosaic lectin and enzyme staining patterns in rat skeletal muscle.

1992 ◽  
Vol 40 (10) ◽  
pp. 1511-1516 ◽  
Author(s):  
S Kirkeby ◽  
T C Bøg-Hansen ◽  
D Moe
Keyword(s):  
Skeletal Muscle ◽  
Staining Pattern ◽  
Muscle Protein ◽  
Lectin Binding ◽  
Succinic Dehydrogenase ◽  
Staining Intensity ◽  
Molecular Weights ◽  
Lectin Staining ◽  
Old Rats ◽  
And Function

We compared the localizations of lectin binding and activity for myosin ATPase and succinic dehydrogenase in sections of the gracilis, soleus, and masseter muscles from 10- and 60-day-old rats. In the 60-day-old rats, incubation of the muscle sections with the lectins ConA, GS-II, HPA, and jacalin gave rise to a mosaic staining pattern, especially in the gracilis muscle, in which the same fibers were strongly stained for ConA, GS-II, and HPA, whereas the staining with jacalin in these fibers was weak, and vice versa. There was no correspondence in the staining patterns for the enzymes and the lectins. In the masseter muscle only GS-II gave rise to distinct differences in the staining intensity between muscle fibers. In 10-day-old rats all fibers in the muscles were moderately stained with ConA, HPA, and jacalin, whereas a chessboard staining pattern could be observed after incubation with GS-II. In an extract of hindleg muscle from 60-day-old rats there was strong affinity for ConA and HPA and weak affinity for GS-II and jacalin, as shown by dot-blotting. After electrophoresis and blotting to nitrocellulose membranes, three muscle protein bands with apparent molecular weights of 100,000, 90,000, and 43,000 showed affinity for ConA, HPA, and GS-II, whereas no bands were jacalin positive. The complex lectin staining pattern in skeletal muscle might be related to development, specialization, and function of the muscles.

Sign in / Sign up

Export Citation Format

Share Document