Qualitative Electron Microscopic Analysis of Cultured Chick Embryonic Cardiac and Skeletal Muscle Cells: The Cellular Effect of Coenzyme Q10 After Exposure to Triton X-100

Although significant progress has been made regarding the structure and function of titin, little data exist on the biosynthesis of this large protein in developing muscle. Using pulse-labeling with [35S]methionine and immunoprecipitation with an anti-titin mAb, we have examined the biosynthesis of titin in synchronized cultures of skeletal muscle cells derived from day 12 chicken embryos. We find that: (a) titin synthesis increases greater than 4-fold during the first week in culture and during this same time period, synthesis of muscle-specific myosin heavy chain increases greater than 12-fold; (b) newly synthesized titin has a t1/2 of approximately 70 h; (c) titin is resistant to extraction with Triton X-100 both during and immediately after its synthesis. These observations suggest that newly synthesized titin molecules are stable proteins that rapidly associate with the cytoskeleton of developing myotubes.

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A Combination of Lipoic Acid Plus Coenzyme Q10 Induces PGC1α, a Master Switch of Energy Metabolism, Improves Stress Response, and Increases Cellular Glutathione Levels in Cultured C2C12 Skeletal Muscle Cells

Oxidative Medicine and Cellular Longevity ◽

10.1155/2012/835970 ◽

2012 ◽

Vol 2012 ◽

pp. 1-9 ◽

Cited By ~ 24

Author(s):

A. E. Wagner ◽

I. M. A. Ernst ◽

M. Birringer ◽

Ö. Sancak ◽

L. Barella ◽

...

Keyword(s):

Skeletal Muscle ◽

Stress Response ◽

Energy Metabolism ◽

Lipoic Acid ◽

Coenzyme Q10 ◽

Defense Mechanisms ◽

Antioxidant Defense ◽

Muscle Cells ◽

Skeletal Muscle Cells ◽

Combined Supplementation

Skeletal muscle function largely depend on intact energy metabolism, stress response, and antioxidant defense mechanisms. In this study, we tested the effect of a combined supplementation ofα-lipoic acid (LA) plus coenzyme Q10 (Q10) on PPARγ-coactivatorα(PGC1α) activity, expression of glutathione-related phase II enzymes and glutathione (GSH) levels in cultured C2C12 myotubes. Supplementation of myotubes with 250 μmol/L LA plus 100 μmol/L Q10 significantly increased nuclear levels of PGC1α, a master switch of energy metabolism and mitochondrial biogenesis. The increase of nuclear PGC1αwas accompanied by an increase in PPARγtransactivation, a downstream target of PGC1α, and an increase in mitochondrial transcription factor A mRNA centrally involved in mitochondrial replication and transcription. Furthermore, supplementation of myotubes with LA plus Q10 resulted in an increase of genes encoding proteins involved in stress response, GSH synthesis, and its recycling. In LA-plus-Q10-treated myotubes a significant 4-fold increase in GSH was evident. This increase in GSH was accompanied by increased nuclear Nrf2 protein levels, partly regulatingγGCS and GST gene expression. Present data suggest that the combined supplementation of skeletal muscle cells with LA plus Q10 may improve energy homeostasis, stress response, and antioxidant defense mechanisms.

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Light and electron microscopic studies on localization of myoglobin in skeletal muscle cells in neuromuscular diseases

Muscle & Nerve ◽

10.1002/mus.880140409 ◽

1991 ◽

Vol 14 (4) ◽

pp. 342-347 ◽

Cited By ~ 11

Author(s):

Hisaomi Kawai ◽

Toshihiko Sebe ◽

Hiroshi Nishino ◽

Yoshihiko Nishida ◽

Shiro Saito

Keyword(s):

Skeletal Muscle ◽

Neuromuscular Diseases ◽

Muscle Cells ◽

Skeletal Muscle Cells ◽

Electron Microscopic ◽

Microscopic Studies

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Elastic energy storage in rigored skeletal muscle cells under physiological loading conditions

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1986.250.1.r56 ◽

1986 ◽

Vol 250 (1) ◽

pp. R56-R64 ◽

Cited By ~ 88

Author(s):

J. G. Tidball ◽

T. L. Daniel

Keyword(s):

Skeletal Muscle ◽

Energy Storage ◽

Elastic Energy ◽

Muscle Cells ◽

Skeletal Muscle Cells ◽

Electron Microscopic ◽

Physiological Range ◽

Parallel Structures ◽

Oriented Parallel

The capability of heavy meromyosin (HMM) to store energy in reversible deformations has been investigated previously; yet, whether HMM is the site of most elastic energy storage in skeletal muscle cells has not been established. We conducted dynamic loading tests on single rigored muscle cells over the physiological range of sarcomere lengths. These tests enabled us to calculate the energy stored in reversible deformations or dissipated in the cell during each cycle of oscillation. Our findings show that these cells are capable of storing approximately 0.5 J . kg-1 of elastic energy during the last 50 ms of passive extension in vivo by agonists and before their own active contraction. Possible sites of this energy storage are HMM subunit 2, the proximal portion of HMM subunit 1, and parallel structures. However, energy storage increases monotonically as myofilament overlap decreases in the physiological range. This negative correlation suggests that HMM subunits are not the primary sites of elastic energy storage. Our electron-microscopic observations show that collagen fibrils at the cell's surface become oriented parallel to the cell's long axis over the range of sarcomere lengths where energy storage increases. This provides a mechanism for the observed increases in elastic energy storage.

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