Microgravity-induced transformations of myosin isoforms and contractile properties of skeletal muscle

1996 ◽  
Vol 81 (1) ◽  
pp. 123-132 ◽  
Author(s):  
V. J. Caiozzo ◽  
F. Haddad ◽  
M. J. Baker ◽  
R. E. Herrick ◽  
N. Prietto ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Level ◽  
Muscle Fibers ◽  
Contractile Properties ◽  
Protein Isoforms ◽  
Control Group ◽  
Type I ◽  
Myosin Isoforms ◽  
Force Frequency ◽  
Mrna Isoform

This study examined the effects of microgravity (14 days) on 1) the contractile properties of the soleus (Sol), an antigravity skeletal muscle; and 2) the myosin heavy chain (MHC) protein and mRNA isoform content of the Sol, vastus intermedius (VI), plantaris (Plan), and tibialis anterior (TA) muscles. The force-velocity relationships of the flight Sol muscles had a significant reduction in maximal isometric tension (-37%) and a corresponding increase in maximal shortening velocity (+20%). Additionally, the force-frequency relationship of the flight Sol muscles was shifted to the right of the ground-based control group. Microgravity had the greatest effect on muscle fiber composition in the Sol muscle, with a reduction in slow muscle fibers and a corresponding increase in muscle fibers categorized as hybrid fibers. The estimated absolute MHC isoform content was altered to the greatest extent in the Sol and VI muscles, with significant decreases and elevations in the slow type I and fast type IIX MHC protein isoforms, respectively. Consistent with the protein data, both the flight Sol and VI muscles exhibited significant elevations in the fast type IIX MHC mRNA isoform. In contrast, however, the flight Plan and TA groups had significant increases in the fast type IIB MHC mRNA isoform content without corresponding changes at the protein level. The results of this study suggest that spaceflight of even short duration produces important changes in the contractile properties of antigravity skeletal muscle. These changes are mediated by alterations in MHC phenotype and reductions in muscle mass. In some instances, the alterations in MHC mRNA isoform content seemed to be uncoupled from those occurring at the protein level. This apparent uncoupling between mRNA and protein expression demonstrates that the effects of microgravity must be better understood at the transcriptional, translational, and post-translational levels.

scholarly journals Coupled expression of troponin T and troponin I isoforms in single skeletal muscle fibers correlates with contractility

2006 ◽  
Vol 290 (2) ◽  
pp. C567-C576 ◽  
Author(s):  
Marco A. Brotto ◽  
Brandon J. Biesiadecki ◽  
Leticia S. Brotto ◽  
Thomas M. Nosek ◽  
Jian-Ping Jin
Keyword(s):  
Skeletal Muscle ◽  
Troponin I ◽  
Troponin T ◽  
Muscle Fibers ◽  
Contractile Properties ◽  
Type I ◽  
Myosin Isoforms ◽  
Mammalian Skeletal Muscle ◽  
Single Fibers ◽  
Skeletal Muscle Fibers

Striated muscle contraction is powered by actin-activated myosin ATPase. This process is regulated by Ca2+ via the troponin complex. Slow- and fast-twitch fibers of vertebrate skeletal muscle express type I and type II myosin, respectively, and these myosin isoenzymes confer different ATPase activities, contractile velocities, and force. Skeletal muscle troponin has also diverged into fast and slow isoforms, but their functional significance is not fully understood. To investigate the expression of troponin isoforms in mammalian skeletal muscle and their functional relationship to that of the myosin isoforms, we concomitantly studied myosin, troponin T (TnT), and troponin I (TnI) isoform contents and isometric contractile properties in single fibers of rat skeletal muscle. We characterized a large number of Triton X-100-skinned single fibers from soleus, diaphragm, gastrocnemius, and extensor digitorum longus muscles and selected fibers with combinations of a single myosin isoform and a single class (slow or fast) of the TnT and TnI isoforms to investigate their role in determining contractility. Types IIa, IIx, and IIb myosin fibers produced higher isometric force than that of type I fibers. Despite the polyploidy of adult skeletal muscle fibers, the expression of fast or slow isoforms of TnT and TnI is tightly coupled. Fibers containing slow troponin had higher Ca2+ sensitivity than that of the fast troponin fibers, whereas fibers containing fast troponin showed a higher cooperativity of Ca2+ activation than that of the slow troponin fibers. These results demonstrate distinct but coordinated regulation of troponin and myosin isoform expression in skeletal muscle and their contribution to the contractile properties of muscle.

Skeletal muscle fiber composition is related to adiposity and in vitro glucose transport rate in humans

1995 ◽  
Vol 268 (3) ◽  
pp. E453-E457 ◽  
Author(s):  
M. S. Hickey ◽  
J. O. Carey ◽  
J. L. Azevedo ◽  
J. A. Houmard ◽  
W. J. Pories ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Skeletal Muscle Fiber ◽  
Transport Rate ◽  
Control Group ◽  
Type I ◽  
Fiber Composition

The purpose of this study was to determine if a relationship exists among skeletal muscle fiber composition, adiposity, and in vitro muscle glucose transport rate in humans. Rectus abdominus muscle was obtained during elective abdominal surgery from nonobese control (n = 12), obese (n = 12), and obese non-insulin-dependent diabetes mellitus (NIDDM) patients (n = 10). The obese NIDDM group had a significantly lower percentage of type I muscle fibers (32.2 +/- 1.9%) than the obese group (40.4 +/- 2.7%), and both obese groups were significantly lower than the control group (50.0 +/- 2.6%). Insulin-stimulated glucose transport, determined on 28 subjects, was significantly lower in both the obese (3.83 +/- 0.48 nmol.min-1.mg-1) and NIDDM (3.93 +/- 1.0 nmol.min-1.mg-1) groups vs. the control group (7.35 +/- 1.50 nmol.min-1.mg-1). Body mass index (BMI) was inversely correlated to percent type I fibers (r = -0.50, P < 0.01) and to the insulin-stimulated glucose transport rate (r = -0.53, P < 0.01). The percentage of type I muscle fibers was related to the insulin-stimulated glucose transport rate (r = 0.57, P < 0.01), although this relationship was not significant after adjusting for BMI. Although these data do not support an independent relationship between fiber type and insulin action in obesity, a reduced skeletal muscle type I fiber population may be one component of a multifactorial process involved in the development of insulin resistance.

Structure of the cortical cytoskeleton in fibers of postural muscles and cardiomyocytes of mice after 30-day 2-g centrifugation

2015 ◽  
Vol 118 (5) ◽  
pp. 613-623 ◽  
Author(s):  
Irina V. Ogneva ◽  
V. Gnyubkin ◽  
N. Laroche ◽  
M. V. Maximova ◽  
I. M. Larina ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tibialis Anterior ◽  
Mechanical Load ◽  
Tibialis Anterior Muscle ◽  
Muscle Fibers ◽  
Control Group ◽  
Negative Effects ◽  
Transverse Stiffness ◽  
G 12 ◽  
Cortical Cytoskeleton

Altered external mechanical loading during spaceflights causes negative effects on muscular and cardiovascular systems. The aim of the study was estimation of the cortical cytoskeleton statement of the skeletal muscle cells and cardiomyocytes. The state of the cortical cytoskeleton in C57BL6J mice soleus, tibialis anterior muscle fibers, and left ventricle cardiomyocytes was investigated after 30-day 2- g centrifugation (“2- g” group) and within 12 h after its completion (“2- g + 12-h” group). We used atomic force microscopy for estimating cell's transverse stiffness, Western blotting for measuring protein content, and RT-PCR for estimating their expression level. The transverse stiffness significantly decreased in cardiomyocytes (by 16%) and increased in skeletal muscles fibers (by 35% for soleus and by 29% for tibialis anterior muscle fibers) in animals of the 2-g group (compared with the control group). For cardiomyocytes, we found that, in the 2- g + 12-h group, α-actinin-1 content decreased in the membranous fraction (by 27%) and increased in cytoplasmic fraction (by 28%) of proteins (compared with the levels in the 2- g group). But for skeletal muscle fibers, similar changes were noted for α-actinin-4, but not for α-actinin-1. In conclusion, we showed that the different isoforms of α-actinins dissociate from cortical cytoskeleton under increased/decreased of mechanical load.

The Adaptive Potential of Skeletal Muscle Fibers

2002 ◽  
Vol 27 (4) ◽  
pp. 423-448 ◽  
Author(s):  
Dirk Pette
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Protein Isoforms ◽  
Mammalian Skeletal Muscle ◽  
Adaptive Potential ◽  
Hybrid Fibers ◽  
Neuromuscular Activity ◽  
Skeletal Muscle Fibers ◽  
Initial Location

Mammalian skeletal muscle fibers display a great adaptive potential. This potential results from the ability of muscle fibers to adjust their molecular, functional, and metabolic properties in response to altered functional demands, such as changes in neuromuscular activity or mechanical loading. Adaptive changes in the expression of myofibrillar and other protein isoforms result in fiber type transitions. These transitions occur in a sequential order and encompass a spectrum of pure and hybrid fibers. Depending on the quality, intensity, and duration of the alterations in functional demand, muscle fibers may undergo functional transitions in the direction of slow or fast, as well as metabolic transitions in the direction of aerobic-oxidative or glycotytic. The maximum range of possible transitions in either direction depends on the fiber phenotype and is determined by its initial location in the fiber spectrum. Key words: Ca-sequestering proteins, energy metabolism, fiber type transition, myofibrillar protein isofonns, myosin, neuromuscular activity

Krüppel‐like factor 10 regulates the contractile properties of skeletal muscle fibers in mice

2021 ◽  
Author(s):  
Malek Kammoun ◽  
Philippe Pouletaut ◽  
Sandrine Morandat ◽  
Malayannan Subramaniam ◽  
John R. Hawse ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Contractile Properties ◽  
Skeletal Muscle Fibers

Effect of Experimentally Induced Chronic Kidney disease on Skeletal, Cardiac and Smooth Muscle fibers of albino rat

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Ghada Lotfy ◽  
Amel Soliman ◽  
Nevine Bahaa ◽  
Mohammed Hegazi
Keyword(s):  
Skeletal Muscle ◽  
Chronic Kidney Disease ◽  
Smooth Muscle ◽  
Kidney Disease ◽  
Intramuscular Injection ◽  
Muscle Fibers ◽  
Lateral Wall ◽  
Control Group ◽  
Once Daily ◽  
Group Ii

Abstract Background Chronic kidney disease (CKD), or chronic renal failure (CRF) as it was historically termed, includes all degrees of decreased renal function, starting from mild, and moderate, to severe chronic kidney failure. Skeletal muscle atrophy frequently complicates the course of CKD and is associated with excess morbidity and mortality. Cardiovascular diseases have been reported to be the leading causes of death in CKD patients. Chronic Kidney Disease was also reported to be associated with an increased incidence of acid-related gastrointestinal disorders. Aim of the work The aim of this study was to investigate the effect of chronic kidney disease experimentally induced by gentamicin intramuscular injection on the histological structure of gastrocnemius skeletal muscle, left ventricular cardiac muscle and smooth muscle fibers of lower esophagus. Materials and methods Twenty male adult Wistar albino rats were randomly and equally divided into two groups. Group I (control group) received physiological saline intramuscular injection, once daily for 28 consecutive days, in a dose equivalent to that taken in group II. Group II (Gentamicin-treated group) were given Gentamicin intramuscular injection for induction of CKD. Gentamicin was given as Gentamycin sulfate, 40 mg/ml (Sandoz, Switzerland), once daily, in a dose of 80 mg/kg/day for 28 days to induce CKD. After 28 days of the first injection of gentamicin, rats were anaesthetized and blood samples were collected to measure the level of serum urea and creatinine. The left kidneys, the middle third of left gastrocnemius muscle, the lateral wall of left ventricle (LV) and the gastroesophageal junction of all rats of both groups (I and II) were processed for light microscopic study. The middle third of left gastrocnemius muscle, the lateral wall of left ventricle (LV) were further processed for transmission electron microscopic study. Histomorphometrical and statistical analysis were also done. Results The LM examination revealed moderate obliteration of glomeruli, dilatation in some renal tubules and collapse in others, mainly in distal convoluted tubules, with significant fibrosis of renal parenchyma. Serum urea and creatinine levels were increased significantly. The skeletal muscle fibers of the rats in group II (CKD) showed focal areas of myofibers degeneration with siginificant fibrosis. The cardiac muscle fibers of the rats in the group II (CKD) showed focal areas of cardiomyocytes degeneration and other areas of significantly hypertrophied fibers. The smooth muscle fibers of the lower esophageal sphincter of the rats in group II (CKD) showed no significant structural changes compared with the control group, however, the myenetric plexus showed multiple pyknotic and karyolitic nuclei with vacuolated cytoplasm. In addition, insignificant increase in the amount of collagen fibers was observed in almost all layers. Conclusion CKD produced moderate atrophy of skeletal muscle fibers, significant increase in the cardiomyocyte size and no significant structural effect of smooth muscle fibers of the lower esophageal sphincter.

Altered expression of skeletal muscle myosin isoforms in cancer cachexia

2002 ◽  
Vol 283 (5) ◽  
pp. C1376-C1382 ◽  
Author(s):  
Gary M. Diffee ◽  
Katherine Kalfas ◽  
Sadeeka Al-Majid ◽  
Donna O. McCarthy
Keyword(s):  
Muscle Atrophy ◽  
Cancer Cachexia ◽  
Muscle Wasting ◽  
Tumor Cell Line ◽  
Protein Isoforms ◽  
Type I ◽  
Myosin Isoforms ◽  
Skeletal Muscle Myosin ◽  
Altered Expression ◽  
Isoform Expression

Cachexia is commonly seen in cancer and is characterized by severe muscle wasting, but little is known about the effect of cancer cachexia on expression of contractile protein isoforms such as myosin. Other causes of muscle atrophy shift expression of myosin isoforms toward increased fast (type II) isoform expression. We injected mice with murine C-26 adenocarcinoma cells, a tumor cell line that has been shown to cause muscle wasting. Mice were killed 21 days after tumor injection, and hindlimb muscles were removed. Myosin heavy chain (MHC) and myosin light chain (MLC) content was determined in muscle homogenates by SDS-PAGE. Body weight was significantly lower in tumor-bearing (T) mice. There was a significant decrease in muscle mass in all three muscles tested compared with control, with the largest decrease occurring in the soleus. Although no type IIb MHC was detected in the soleus samples from control mice, type IIb comprised 19% of the total MHC in T soleus. Type I MHC was significantly decreased in T vs. control soleus muscle. MHC isoform content was not significantly different from control in plantaris and gastrocnemius muscles. These data are the first to show a change in myosin isoform expression accompanying muscle atrophy during cancer cachexia.

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.

Sign in / Sign up

Export Citation Format

Share Document