scholarly journals Visualization of Mitochondrial Ca2+ Signals in Skeletal Muscle of Zebrafish Embryos with Bioluminescent Indicators

2019 ◽  
Vol 20 (21) ◽  
pp. 5409 ◽  
Author(s):  
Manuel Vicente ◽  
Jussep Salgado-Almario ◽  
Joaquim Soriano ◽  
Miguel Burgos ◽  
Beatriz Domingo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Contractions ◽  
Zebrafish Embryos ◽  
Mitochondrial Matrix ◽  
Mitochondrial Calcium Uniporter ◽  
Calcium Uniporter ◽  
Skeletal Muscle Contraction ◽  
Spatio Temporal ◽  
Mitochondrial Uncoupler

Mitochondria are believed to play an important role in shaping the intracellular Ca2+ transients during skeletal muscle contraction. There is discussion about whether mitochondrial matrix Ca2+ dynamics always mirror the cytoplasmic changes and whether this happens in vivo in whole organisms. In this study, we characterized cytosolic and mitochondrial Ca2+ signals during spontaneous skeletal muscle contractions in zebrafish embryos expressing bioluminescent GFP-aequorin (GA, cytoplasm) and mitoGFP-aequorin (mitoGA, trapped in the mitochondrial matrix). The Ca2+ transients measured with GA and mitoGA reflected contractions of the trunk observed by transmitted light. The mitochondrial uncoupler FCCP and the inhibitor of the mitochondrial calcium uniporter (MCU), DS16570511, abolished mitochondrial Ca2+ transients whereas they increased the frequency of cytosolic Ca2+ transients and muscle contractions, confirming the subcellular localization of mitoGA. Mitochondrial Ca2+ dynamics were also determined with mitoGA and were found to follow closely cytoplasmic changes, with a slower decay. Cytoplasmic Ca2+ kinetics and propagation along the trunk and tail were characterized with GA and with the genetically encoded fluorescent Ca2+ indicator, Twitch-4. Although fluorescence provided a better spatio-temporal resolution, GA was able to resolve the same kinetic parameters while allowing continuous measurements for hours.

scholarly journals The Mitochondrial Calcium Uniporter Controls Skeletal Muscle Trophism In Vivo

Cell Reports ◽  
2015 ◽  
Vol 10 (8) ◽  
pp. 1269-1279 ◽  
Author(s):  
Cristina Mammucari ◽  
Gaia Gherardi ◽  
Ilaria Zamparo ◽  
Anna Raffaello ◽  
Simona Boncompagni ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Calcium ◽  
Mitochondrial Calcium Uniporter ◽  
Calcium Uniporter

A malonyl-CoA fuel-sensing mechanism in muscle: effects of insulin, glucose, and denervation

1995 ◽  
Vol 269 (2) ◽  
pp. E283-E289 ◽  
Author(s):  
A. K. Saha ◽  
T. G. Kurowski ◽  
N. B. Ruderman
Keyword(s):  
Skeletal Muscle ◽  
Plasma Insulin ◽  
Contractile Activity ◽  
High Plasma ◽  
Muscle Contractions ◽  
Glucose Levels ◽  
Malonyl Coa ◽  
Ad Libitum ◽  
Sciatic Nerve Stimulation

Increases in the concentration of malonyl-CoA in skeletal muscle have been observed in the KKAy mouse, an obese rodent with high plasma insulin and glucose levels [Saha et al. Am. J. Physiol. 267 (Endocrinol. Metab. 30): E95-E101, 1994]. To assess whether insulin and glucose directly regulate malonyl-CoA in muscle, soleus muscles from young rats were incubated with insulin and glucose at various concentrations, and their content of malonyl-CoA was determined. In addition, the effect on malonyl-CoA of denervation and electrically induced muscle contractions was assessed. The concentration of malonyl-CoA in the soleus, taken directly from a rat fed ad libitum, was 2.0 +/- 0.2 nmol/g. In muscles incubated for 20 min in a medium devoid of added insulin and glucose, the concentration was decreased to 0.8 +/- 0.2 nmol/g. When the medium contained 0.5, 7.5, or 30 mM glucose, malonyl-CoA levels were 1.3 +/- 0.1, 1.8 +/- 0.1, or 2.4 +/- 0.2 nmol/g, respectively, in the absence of insulin and 1.7 +/- 0.1, 4.6 +/- 0.3, or 5.5 +/- 0.6 nmol/g in its presence (10 mU/ml). Compared with its level in a control muscle, the concentration of malonyl-CoA was increased threefold in the soleus 6-8 h after denervation and remained twofold higher for > or = 48 h. In contrast, muscle contractions induced by sciatic nerve stimulation, in vivo, acutely decreased the concentration of malonyl-CoA by 30-35%. The results indicate that insulin and glucose, and probably contractile activity, regulate the concentration of malonyl-CoA in muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Syncoilin is required for generating maximum isometric stress in skeletal muscle but dispensable for muscle cytoarchitecture

2008 ◽  
Vol 294 (5) ◽  
pp. C1175-C1182 ◽  
Author(s):  
Jianlin Zhang ◽  
Marie-Louise Bang ◽  
David S. Gokhin ◽  
Yingchun Lu ◽  
Li Cui ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Striated Muscle ◽  
Neuromuscular Diseases ◽  
Eccentric Contraction ◽  
Lateral Force ◽  
Force Transmission ◽  
Skeletal Muscle Contraction ◽  
Supportive Role

Syncoilin is a striated muscle-specific intermediate filament-like protein, which is part of the dystrophin-associated protein complex (DPC) at the sarcolemma and provides a link between the extracellular matrix and the cytoskeleton through its interaction with α-dystrobrevin and desmin. Its upregulation in various neuromuscular diseases suggests that syncoilin may play a role in human myopathies. To study the functional role of syncoilin in cardiac and skeletal muscle in vivo, we generated syncoilin-deficient ( syncoilin−/−) mice. Our detailed analysis of these mice up to 2 yr of age revealed that syncoilin is entirely dispensable for cardiac and skeletal muscle development and maintenance of cellular structure but is required for efficient lateral force transmission during skeletal muscle contraction. Notably, syncoilin−/− skeletal muscle generates less maximal isometric stress than wild-type (WT) muscle but is as equally susceptible to eccentric contraction-induced injury as WT muscle. This suggests that syncoilin may play a supportive role for desmin in the efficient coupling of mechanical stress between the myofibril and fiber exterior. It is possible that the reduction in isometric stress production may predispose the syncoilin skeletal muscle to a dystrophic condition.

scholarly journals A novel protoapigenone analog RY10-4 induces apoptosis of breast cancer cells by regulating mitochondrial Ca2+ influx through the mitochondrial calcium uniporter

2020 ◽  
Author(s):  
Pingping Xue ◽  
Qian Chen ◽  
Xiuhua Ren ◽  
Yimin Yang ◽  
Xiaofan Yang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Flavonoid Compound ◽  
Mitochondrial Calcium ◽  
Mitochondrial Apoptosis ◽  
Apoptosis Pathway ◽  
Mitochondrial Calcium Uniporter ◽  
Calcium Uniporter

Abstract Background Protoapigenone, as a flavonoid compound with a specific nonaromatic B-ring, exhibits extraordinary antitumor activities against a broad spectrum of human cancer cells. Here we developed a novel protoapigenone analog RY10-4, which induces the apoptosis of various tumor cells, especially for breast cancer cells, but the underlying mechanism involved in the apoptotic process remains unclear. Methods MTT assay, colony-formation assay and flow cytometry were applied to evaluate the proliferation and apoptosis of breast cancer cells. Cytoplasmic calcium ([Ca2+]c) and mitochondrial calcium ([Ca2+]m) of the breast cancer cells were measured by the Fluo-2 and Rhod-2 probes, respectively. The mitochondrial reactive oxygen species (mtROS), membrane potential (ΔΨm) and permeability transition pore (mPTP) were analyzed by MitoSOX, JC-1 probes and Calcein/AM, respectively. Furthermore, Western bolt assay was adopted for the exploration of the mitochondrial apoptosis pathway. Besides, the xenograft assay was performed to investigate the role of RY10-4 in breast cancer cells in vivo. Results Obviously, RY10-4 could effectively suppress the proliferation and induce the apoptosis of breast cancer cells. Furthermore, the [Ca2+]c and [Ca2+]m of MDA-MB-231 cells were up-regulated after the treatment of RY10-4, resulting in the mtROS accumulation, ΔΨm depolarization and mPTP opening. And finally, the mitochondrial apoptosis was activated by the release of cytochrome C. Interestingly, the inhibition of mitochondrial calcium uniporter (MCU) with Ru360 attenuated the overload of [Ca2+]m and blocked the apoptosis of MDA-MB-231 cells induced by RY10-4, which was also consistent with the in vivo results. Conclusions From the results we concluded that RY10-4 could induce apoptosis of breast cancer cells by elevating [Ca2+]m through MCU. Our work contributed previously unknown insights into the mechanisms involving in the clinical efficacy of RY10-4 on breast cancer cells, which also advanced calcium homeostasis as a potential target for chemotherapeutic drugs.

scholarly journals In vivo imaging of intracellular Ca 2+ after muscle contractions and direct Ca 2+ injection in rat skeletal muscle in diabetes

2013 ◽  
Vol 27 (S1) ◽  
Author(s):  
Hiroaki Eshima ◽  
Yoshinori Tanaka ◽  
Takashi Sonobe ◽  
Tadakatsu Inagaki ◽  
David C Poole ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
In Vivo Imaging ◽  
Muscle Contractions ◽  
Rat Skeletal Muscle ◽  
Intracellular Ca

scholarly journals On characterizing skeletal muscle contraction properties. Experimental and simulation methodology

1970 ◽  
pp. 63
Author(s):  
M. Sierra ◽  
M.J. Muñoz ◽  
J. Grasa
Keyword(s):  
Skeletal Muscle ◽  
Tibialis Anterior ◽  
Tetanic Contraction ◽  
Simulation Methodology ◽  
Skeletal Muscle Fatigue ◽  
Skeletal Muscle Contraction ◽  
Experimental Parameters ◽  
Male Wistar Rats ◽  
Different Characteristics

The main objective of this work is to characterize the fatigue contractile properties of threedifferent rat muscles (Tibialis Anterior, Extensor Digitorium Longus and Soleus) in order toobtain experimental parameters for numerical simulations.Experiments were conducted “in vivo" on three groups (n = 6) of male Wistar rats (210 +/- 11g)using a protocol developed by authors in previous works. Muscles were subjected to anelectrical stimulus to achieve tetanic contraction during ten seconds. Digital Image Correlationwas used during tests for 3D strain and displacements measurement that allow the correlationwith the finite element simulations.By means of Computed Tomography, a precise reconstruction of both bone and muscle of therat hindlimb geometry was obtained. The methodology proposed allows to obtain and validatecomputational simulations of skeletal muscle fatigue under different characteristics related tofiber types.63

scholarly journals The mitochondrial calcium uniporter is crucial for the generation of fast cortical network rhythms

2019 ◽  
Vol 40 (11) ◽  
pp. 2225-2239 ◽  
Author(s):  
Carlos Bas-Orth ◽  
Justus Schneider ◽  
Andrea Lewen ◽  
Jamie McQueen ◽  
Kerstin Hasenpusch-Theil ◽  
...  
Keyword(s):  
Energy Homeostasis ◽  
Pyramidal Cells ◽  
Gamma Oscillations ◽  
Spike Timing ◽  
Mitochondrial Calcium ◽  
Attention And Memory ◽  
Mitochondrial Calcium Uniporter ◽  
Sharp Waves ◽  
Calcium Uniporter

The role of the mitochondrial calcium uniporter (MCU) gene ( Mcu) in cellular energy homeostasis and generation of electrical brain rhythms is widely unknown. We investigated this issue in mice and rats using Mcu-knockout and -knockdown strategies in vivo and in situ and determined the effects of these genetic manipulations on hippocampal gamma oscillations (30–70 Hz) and sharp wave-ripples. These physiological network states require precise neurotransmission between pyramidal cells and inhibitory interneurons, support spike-timing and synaptic plasticity and are associated with perception, attention and memory. Absence of the MCU resulted in (i) gamma oscillations with decreased power (by >40%) and lower synchrony, including less precise neural action potential generation (‘spiking'), (ii) sharp waves with decreased incidence (by about 22%) and decreased fast ripple frequency (by about 3%) and (iii) lack of activity-dependent pyruvate dehydrogenase dephosphorylation. However, compensatory adaptation in gene expression related to mitochondrial function and glucose metabolism was not detected. These data suggest that the neuronal MCU is crucial for the generation of network rhythms, most likely by influences on oxidative phosphorylation and perhaps by controlling cytoplasmic Ca2+ homeostasis. This work contributes to an increased understanding of mitochondrial Ca2+ uptake in cortical information processing underlying cognition and behaviour.

scholarly journals Skeletal muscle metabolism in sea-acclimatized king penguins. I. Thermogenic mechanisms

2020 ◽  
Vol 223 (21) ◽  
pp. jeb233668
Author(s):  
Damien Roussel ◽  
Marion Le Coadic ◽  
Jean-Louis Rouanet ◽  
Claude Duchamp
Keyword(s):  
Skeletal Muscle ◽  
Muscle Metabolism ◽  
Exact Nature ◽  
Skeletal Muscle Metabolism ◽  
Energy Demands ◽  
Skeletal Muscle Contraction ◽  
Drastic Increase ◽  
Shivering Thermogenesis

ABSTRACTAt fledging, king penguin juveniles undergo a major energetic challenge to overcome the intense and prolonged energy demands for thermoregulation and locomotion imposed by life in cold seas. Among other responses, sea acclimatization triggers fuel selection in skeletal muscle metabolism towards lipid oxidation in vitro, which is reflected by a drastic increase in lipid-induced thermogenesis in vivo. However, the exact nature of skeletal muscle thermogenic mechanisms (shivering and/or non-shivering thermogenesis) remains undefined. The aim of the present study was to determine in vivo whether the capacity for non-shivering thermogenesis was enhanced by sea acclimatization. We measured body temperature, metabolic rate, heart rate and shivering activity in fully immersed king penguins (Aptenodytes patagonicus) exposed to water temperatures ranging from 12 to 29°C. Results from terrestrial pre-fledging juveniles were compared with those from sea-acclimatized immature penguins (hereafter ‘immatures’). The capacity for thermogenesis in water was as effective in juveniles as in immatures, while the capacity for non-shivering thermogenesis was not reinforced by sea acclimatization. This result suggests that king penguins mainly rely on skeletal muscle contraction (shivering or locomotor activity) to maintain endothermy at sea. Sea-acclimatized immature penguins also exhibited higher shivering efficiency and oxygen pulse (amount of oxygen consumed or energy expended per heartbeat) than pre-fledging juvenile birds. Such increase in shivering and cardiovascular efficiency may favor a more efficient activity–thermoregulatory heat substitution providing penguins with the aptitude to survive the tremendous energetic challenge imposed by marine life in cold circumpolar oceans.

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