scholarly journals Desmin Cytoskeleton Linked to Muscle Mitochondrial Distribution and Respiratory Function

2000 ◽  
Vol 150 (6) ◽  
pp. 1283-1298 ◽  
Author(s):  
Derek J. Milner ◽  
Manolis Mavroidis ◽  
Noah Weisleder ◽  
Yassemi Capetanaki
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Muscle ◽  
Soleus Muscle ◽  
Mitochondrial Respiration ◽  
Respiratory Function ◽  
Structural Defects ◽  
Ultrastructural Observation ◽  
Ultrastructural Studies ◽  
Mitochondrial Distribution

Ultrastructural studies have previously suggested potential association of intermediate filaments (IFs) with mitochondria. Thus, we have investigated mitochondrial distribution and function in muscle lacking the IF protein desmin. Immunostaining of skeletal muscle tissue sections, as well as histochemical staining for the mitochondrial marker enzymes cytochrome C oxidase and succinate dehydrogenase, demonstrate abnormal accumulation of subsarcolemmal clumps of mitochondria in predominantly slow twitch skeletal muscle of desmin-null mice. Ultrastructural observation of desmin-null cardiac muscle demonstrates in addition to clumping, extensive mitochondrial proliferation in a significant fraction of the myocytes, particularly after work overload. These alterations are frequently associated with swelling and degeneration of the mitochondrial matrix. Mitochondrial abnormalities can be detected very early, before other structural defects become obvious. To investigate related changes in mitochondrial function, we have analyzed ADP-stimulated respiration of isolated muscle mitochondria, and ADP-stimulated mitochondrial respiration in situ using saponin skinned muscle fibers. The in vitro maximal rates of respiration in isolated cardiac mitochondria from desmin-null and wild-type mice were similar. However, mitochondrial respiration in situ is significantly altered in desmin-null muscle. Both the maximal rate of ADP-stimulated oxygen consumption and the dissociation constant (Km) for ADP are significantly reduced in desmin-null cardiac and soleus muscle compared with controls. Respiratory parameters for desmin-null fast twitch gastrocnemius muscle were unaffected. Additionally, respiratory measurements in the presence of creatine indicate that coupling of creatine kinase and the adenine translocator is lost in desmin-null soleus muscle. This coupling is unaffected in cardiac muscle from desmin-null animals. All of these studies indicate that desmin IFs play a significant role in mitochondrial positioning and respiratory function in cardiac and skeletal muscle.

Does impaired mitochondrial function affect insulin signaling and action in cultured human skeletal muscle cells?

2008 ◽  
Vol 294 (1) ◽  
pp. E97-E102 ◽  
Author(s):  
Audrey E. Brown ◽  
Matthias Elstner ◽  
Stephen J. Yeaman ◽  
Douglass M. Turnbull ◽  
Mark Walker
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Insulin Signaling ◽  
Mitochondrial Respiration ◽  
Respiratory Function ◽  
Insulin Action ◽  
Human Skeletal Muscle ◽  
Human Skeletal Muscle Cells ◽  
Basal Glucose Uptake

Insulin-resistant type 2 diabetic patients have been reported to have impaired skeletal muscle mitochondrial respiratory function. A key question is whether decreased mitochondrial respiration contributes directly to the decreased insulin action. To address this, a model of impaired cellular respiratory function was established by incubating human skeletal muscle cell cultures with the mitochondrial inhibitor sodium azide and examining the effects on insulin action. Incubation of human skeletal muscle cells with 50 and 75 μM azide resulted in 48 ± 3% and 56 ± 1% decreases, respectively, in respiration compared with untreated cells mimicking the level of impairment seen in type 2 diabetes. Under conditions of decreased respiratory chain function, insulin-independent (basal) glucose uptake was significantly increased. Basal glucose uptake was 325 ± 39 pmol/min/mg (mean ± SE) in untreated cells. This increased to 669 ± 69 and 823 ± 83 pmol/min/mg in cells treated with 50 and 75 μM azide, respectively (vs. untreated, both P < 0.0001). Azide treatment was also accompanied by an increase in basal glycogen synthesis and phosphorylation of AMP-activated protein kinase. However, there was no decrease in glucose uptake following insulin exposure, and insulin-stimulated phosphorylation of Akt was normal under these conditions. GLUT1 mRNA expression remained unchanged, whereas GLUT4 mRNA expression increased following azide treatment. In conclusion, under conditions of impaired mitochondrial respiration there was no evidence of impaired insulin signaling or glucose uptake following insulin exposure in this model system.

scholarly journals Biogenesis of transverse tubules: immunocytochemical localization of a transverse tubular protein (TS28) and a sarcolemmal protein (SL50) in rabbit skeletal muscle developing in situ.

1990 ◽  
Vol 110 (4) ◽  
pp. 1187-1198 ◽  
Author(s):  
S Yuan ◽  
W Arnold ◽  
A O Jorgensen
Keyword(s):  
Skeletal Muscle ◽  
Subcellular Distribution ◽  
Developmental Stages ◽  
Rabbit Skeletal Muscle ◽  
Cell Periphery ◽  
Stages Of Development ◽  
Transverse Tubules ◽  
Ultrastructural Studies ◽  
Immunofluorescence Labeling

To study the biogenesis of transverse tubules, the temporal appearance and distribution of TS28 (a specific marker of transverse tubules absent from the sarcolemma in adult skeletal muscle; 28,000 Mr) and SL50 (specifically associated with the sarcolemma and absent from the region of the transverse tubules in adult rabbit skeletal muscle) (Jorgensen, A.O., W. Arnold, A. C.-Y. Shen, S. Yuan, M. Gaver, and K.P. Campbell. 1990. J. Cell Biol. 110:1173-1185) were determined in rabbit skeletal muscle developing in situ (day 17 of gestation to day 15 newborn) by indirect immunofluorescence labeling. The results presented show that the temporal appearance and subcellular distribution of TS28 is distinct from that of SL50 at the developmental stages examined. TS28 was first detected in some, but not all, multinucleated myotubes on day 17 of gestation. At this stage of development, SL50 and the Ca2(+)-ATPase of the sarcoplasmic reticulum were already present in all myotubes. TS28 first appeared in discrete foci mostly confined to the cell periphery of the myotubes. At subsequent stages of development (days 19-24 of gestation), TS28 was also found in shoft finger-like structures extending obliquely and transversely from the cell periphery towards the center of the myotubes. 1-2 d after birth, TS28 was observed in an anastomosing network composed of transversely oriented chickenwire-like networks extending throughout the cytoplasm and interconnected by longitudinally oriented fiber-like structures. As development proceeded, the transversely oriented network became increasingly dominant. By day 10 of postnatal development, the longitudinally oriented component of the tubular network was not regularly observed. At none of the developmental stages examined was TS28 observed to be uniformly distributed at the cell periphery. SL50, like TS28, first appeared in discrete foci at the cell periphery. However, shortly after its first appearance it appeared to be distributed along the entire cell periphery. Although the intensity of SL50 labeling increased with development, it remained confined to the sarcolemma and was absent from the interior regions of the myofibers, where transverse tubules were present at all subsequent developmental stages examined. Immunoblotting of cell extracts from skeletal muscle tissue at various stages of development showed that SL50 was first detected on day 24 of gestation, while TS28 was not detected until days 1-2 after birth. Comparison of these results with previous ultrastructural studies of the formation of transverse tubules supports the idea that the temporal appearance and subcellular distribution of TS28 correspond very closely to that of the distribution of forming transverse tubules in rabbit skeletal muscle developing in situ.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Computational assessment of transport distances in living skeletal muscle fibers studied in situ

2020 ◽  
Author(s):  
Kenth-Arne Hansson ◽  
Andreas Våvang Solbrå ◽  
Kristian Gundersen ◽  
Jo Christiansen Bruusgaard
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Extensor Digitorum Longus ◽  
Transportation Network ◽  
Muscle Fibers ◽  
Extensor Digitorum ◽  
Nuclear Density ◽  
Skeletal Muscle Fibers ◽  
Longus Muscle

AbstractTransport distances in skeletal muscle fibers are mitigated by these cells having multiple nuclei. We have studied mouse living slow (soleus) and fast (extensor digitorum longus) muscle fibers in situ and determined cellular dimensions and the positions of all the nuclei within fiber segments. We modelled the effect of placing nuclei optimally and randomly using the nuclei as the origin of a transportation network. It appeared that an equidistant positioning of nuclei minimizes transport distances along the surface for both muscles. In the soleus muscle however, which were richer in nuclei, positioning of nuclei to reduce transport distances to the cytoplasm were of less importance, and these fibers exhibit a pattern not statistically different from a random positioning of nuclei. Together, these results highlight the importance of spatially distribute nuclei to minimize transport distances to the surface when nuclear density is low, while it appears that the distribution are of less importance at higher nuclear densities.

scholarly journals Endothelial nitric oxide synthase (NOS) deficiency affects energy metabolism pattern in murine oxidative skeletal muscle

2002 ◽  
Vol 368 (1) ◽  
pp. 341-347 ◽  
Author(s):  
Iman MOMKEN ◽  
Dominique FORTIN ◽  
Bernard SERRURIER ◽  
Xavier BIGARD ◽  
Renée VENTURA-CLAPIER ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Energy Metabolism ◽  
Nitric Oxide Synthase ◽  
Soleus Muscle ◽  
Mitochondrial Respiration ◽  
Endothelial Nitric Oxide Synthase ◽  
Oxidative Capacity ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Oxidative capacity of muscles correlates with capillary density and with microcirculation, which in turn depend on various regulatory factors, including NO generated by endothelial nitric oxide synthase (eNOS). To determine the role of eNOS in patterns of regulation of energy metabolism in various muscles, we studied mitochondrial respiration in situ in saponin-permeabilized fibres as well as the energy metabolism enzyme profile in the cardiac, soleus (oxidative) and gastrocnemius (glycolytic) muscles isolated from mice lacking eNOS (eNOS-/-). In soleus muscle, the absence of eNOS induced a marked decrease in both basal mitochondrial respiration without ADP (-32%; P<0.05) and maximal respiration in the presence of ADP (-29%; P<0.05). Furthermore, the eNOS-/- soleus muscle showed a decrease in total creatine kinase (-29%; P<0.05), citrate synthase (-31%; P<0.01), adenylate kinase (-27%; P<0.05), glyceraldehyde-3-phosphate dehydrogenase (-43%; P<0.01) and pyruvate kinase (-26%; P<0.05) activities. The percentage of myosin heavy chains I (slow isoform) was significantly increased from 24.3±1.5% in control to 30.1±1.1% in eNOS-/- soleus muscle (P<0.05) at the expense of a slight non-significant decrease in the three other (fast) isoforms. Besides, eNOS-/- soleus showed a 28% loss of weight. Interestingly, we did not find differences in any parameters in cardiac and gastrocnemius muscles compared with respective controls. These results show that eNOS knockout has an important effect on muscle oxidative capacity as well on the activities of energy metabolism enzymes in oxidative (soleus) muscle. The absence of such effects in cardiac and glycolytic (gastrocnemius) muscle suggests a specific role for eNOS-produced NO in oxidative skeletal muscle.

In vitro responses of cat skeletal muscle to halothane and caffeine

1985 ◽  
Vol 58 (2) ◽  
pp. 521-527 ◽  
Author(s):  
P. A. Deuster ◽  
E. L. Bockman ◽  
S. M. Muldoon
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Soleus Muscle ◽  
Ringer Solution ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Type Ii

Strips of soleus (100% type I) and gracilis (90% type II) muscle were obtained from anesthetized cats and mounted in organ baths filled with aerated Krebs-Ringer solution (37 degrees C). The contractile patterns in response to electrical stimulation (0.1 Hz, 25 V, 5 ms), caffeine, halothane, and caffeine in the presence of halothane were examined in the two fiber types. The ability of 25 microM dantrolene to alter the contractile patterns was also evaluated. In vitro contractile properties in response to electrical stimulation were similar to properties observed in situ, except that twitch tension in soleus muscle was significantly less in vitro than in situ. In the presence of halothane, type I soleus muscle developed a rapid contracture. The contracture was blocked by pretreatment with dantrolene and was reversed by addition of dantrolene at the peak of the response. Halothane-induced contractures were not observed at any time in type II gracilis. Type I soleus was also significantly more sensitive both to caffeine alone and to caffeine in the presence of halothane than was type II gracilis. In both fiber types, halothane increased the sensitivity of the muscles to caffeine. Dantrolene attenuated caffeine-induced contractures in both fiber types, but the attenuating effect was less in the presence of halothane. The findings of a halothane-induced contracture in the cat soleus and differential sensitivities of the two muscle fiber types to caffeine indicate that further studies in these two muscles may be useful for delineating the mechanisms inducing contracture in muscle from individuals susceptible to malignant hyperthermia.

Relative metabolic utilization of in situ rabbit soleus muscle: thermistor-based measurements and model

2000 ◽  
Vol 203 (23) ◽  
pp. 3667-3674
Author(s):  
K.J. Gustafson ◽  
G.D. Egrie ◽  
S.H. Reichenbach
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Muscle Length ◽  
Multiple Linear Regression Model ◽  
Active Tension ◽  
Contraction Duration ◽  
Continuous Power

Electrically conditioned skeletal muscle can provide the continuous power source for cardiac assistance devices. Optimization of the available sustained power from in vivo skeletal muscle requires knowledge of its metabolic utilization and constraints. A thermistor-based technique has been developed to measure temperature changes and to provide a relative estimate for metabolic utilization of in situ rabbit soleus muscle. The relative thermistor response, active tension and muscle displacement were measured during cyclic isometric and isotonic contractions across a range of muscle tensions and contraction durations. The thermistor response demonstrated linear relationships versus both contraction duration at a fixed muscle length and active tension at a fixed contraction duration (r(2)=0.90+/−0.14 and 0.70+/−0.21, respectively; means +/− s.d.). A multiple linear regression model was developed to predict normalized thermistor response, DeltaT, across a range of conditions. Significant model variables were identified using a backward stepwise regression procedure. The relationships for the in situ muscles were qualitatively similar to those reported for mammalian in vitro muscle fiber preparations. The model had the form DeltaT=C+at(c)F+bW, where the constant C, and coefficients for the contraction duration t(c) (ms), normalized active tension F and normalized net work W were C=−1.00 (P&lt;0.001), a=5.97 (P&lt;0.001) and b=2.12 (P&lt;0.001).

Tissue adenosine content in active soleus and gracilis muscles of cats

1983 ◽  
Vol 244 (4) ◽  
pp. H552-H559 ◽  
Author(s):  
E. L. Bockman ◽  
J. E. McKenzie
Keyword(s):  
Cardiac Muscle ◽  
Soleus Muscle ◽  
Gracilis Muscle ◽  
Fiber Types ◽  
Amp Deaminase ◽  
Vascular Conductance ◽  
Cast Doubt ◽  
Slow Twitch ◽  
Fast Twitch

Vascularly isolated cat soleus and gracilis muscles were stimulated to contract isometrically and were then frozen in situ. Adenosine, inosine, and hypoxanthine (nucleosides), and lactate were measured in neutralized, perchloric acid extracts of muscle. During contraction, nucleoside content increased in soleus muscle but changed little in gracilis muscle. However, adenosine content did not correlate with vascular conductance or oxygen consumption in either soleus or gracilis muscle. Adenosine content did correlate with lactate content in soleus but not gracilis muscle. The activity of AMP deaminase was highest in cat gracilis muscle and lowest in dog cardiac muscle. The activity of 5'-nucleotidase was lowest in cat gracilis muscle and highest in dog cardiac muscle. Cat soleus and dog gracilis muscles had intermediate activities of both enzymes. The findings of the present study do not support a role for adenosine in mediating prolonged active hyperemia in fast-twitch gracilis muscle of cats and cast doubt on such a role in slow-twitch soleus muscle of cats. Differences in the activities of AMP deaminase and 5'-nucleotidase provide a qualitative, biochemical explanation for apparent differences in net adenosine production among muscles composed of different fiber types and between skeletal and cardiac muscle.

scholarly journals Calpain-mediated proteolysis of tropomodulin isoforms leads to thin filament elongation in dystrophic skeletal muscle

2014 ◽  
Vol 25 (6) ◽  
pp. 852-865 ◽  
Author(s):  
David S. Gokhin ◽  
Matthew T. Tierney ◽  
Zhenhua Sui ◽  
Alessandra Sacco ◽  
Velia M. Fowler
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Thin Filament ◽  
Cytoskeletal Proteins ◽  
Structural Proteins ◽  
Mdx Mice ◽  
Dependent Manner ◽  
Filament Length ◽  
Mechanical Instability

Duchenne muscular dystrophy (DMD) induces sarcolemmal mechanical instability and rupture, hyperactivity of intracellular calpains, and proteolytic breakdown of muscle structural proteins. Here we identify the two sarcomeric tropomodulin (Tmod) isoforms, Tmod1 and Tmod4, as novel proteolytic targets of m-calpain, with Tmod1 exhibiting ∼10-fold greater sensitivity to calpain-mediated cleavage than Tmod4 in situ. In mdx mice, increased m-calpain levels in dystrophic soleus muscle are associated with loss of Tmod1 from the thin filament pointed ends, resulting in ∼11% increase in thin filament lengths. In mdx/mTR mice, a more severe model of DMD, Tmod1 disappears from the thin filament pointed ends in both tibialis anterior (TA) and soleus muscles, whereas Tmod4 additionally disappears from soleus muscle, resulting in thin filament length increases of ∼10 and ∼12% in TA and soleus muscles, respectively. In both mdx and mdx/mTR mice, both TA and soleus muscles exhibit normal localization of α-actinin, the nebulin M1M2M3 domain, Tmod3, and cytoplasmic γ-actin, indicating that m-calpain does not cause wholesale proteolysis of other sarcomeric and actin cytoskeletal proteins in dystrophic skeletal muscle. These results implicate Tmod proteolysis and resultant thin filament length misspecification as novel mechanisms that may contribute to DMD pathology, affecting muscles in a use- and disease severity–dependent manner.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

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