scholarly journals Dexamethasone stimulates store-operated calcium entry and protein degradation in cultured L6 myotubes through a phospholipase A2-dependent mechanism

2010 ◽  
Vol 298 (5) ◽  
pp. C1127-C1139 ◽  
Author(s):  
Kiyoshi Itagaki ◽  
Michael Menconi ◽  
Bozena Antoniu ◽  
Qin Zhang ◽  
Patricia Gonnella ◽  
...  
Keyword(s):  
Calcium Channel ◽  
Protein Degradation ◽  
Intracellular Calcium ◽  
Muscle Wasting ◽  
Muscle Protein ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Fluorescence Measurements ◽  
Store Operated Calcium Entry

Muscle wasting in various catabolic conditions is at least in part regulated by glucocorticoids. Increased calcium levels have been reported in atrophying muscle. Mechanisms regulating calcium homeostasis in muscle wasting, in particular the role of glucocorticoids, are poorly understood. Here we tested the hypothesis that glucocorticoids increase intracellular calcium concentrations in skeletal muscle and stimulate store-operated calcium entry (SOCE) and that these effects of glucocorticoids may at least in part be responsible for glucocorticoid-induced protein degradation. Treatment of cultured myotubes with dexamethasone, a frequently used in vitro model of muscle wasting, resulted in increased intracellular calcium concentrations determined by fura-2 AM fluorescence measurements. When SOCE was measured by using calcium “add-back” to muscle cells after depletion of intracellular calcium stores, results showed that SOCE was increased 15–25% by dexamethasone and that this response to dexamethasone was inhibited by the store-operated calcium channel blocker BTP2. Dexamethasone treatment stimulated the activity of calcium-independent phospholipase A2(iPLA2), and dexamethasone-induced increase in SOCE was reduced by the iPLA2inhibitor bromoenol lactone (BEL). In additional experiments, treatment of myotubes with the store-operated calcium channel inhibitor gadolinium ion or BEL reduced dexamethasone-induced increase in protein degradation. Taken together, the results suggest that glucocorticoids increase calcium concentrations in myocytes and stimulate iPLA2-dependent SOCE and that glucocorticoid-induced muscle protein degradation may at least in part be regulated by increased iPLA2activity, SOCE, and cellular calcium levels.

Quercetin enhances the antitumor effect of trichostatin A and suppresses muscle wasting in tumor-bearing mice

2018 ◽  
Vol 9 (2) ◽  
pp. 871-879 ◽  
Author(s):  
Shu-Ting Chan ◽  
Cheng-Hung Chuang ◽  
Yi-Chin Lin ◽  
Jiunn-Wang Liao ◽  
Chong-Kuei Lii ◽  
...  
Keyword(s):  
Protein Degradation ◽  
Antitumor Effect ◽  
Muscle Wasting ◽  
Muscle Protein ◽  
Trichostatin A ◽  
Tumor Bearing ◽  
Muscle Protein Degradation

Quercetin prevents TSA-induced muscle wasting by down-regulating FOXO1 mediated muscle protein degradation.

Store-operated Calcium Entry-associated Regulatory Factor Regulates Airway Inflammation and Airway Remodeling in Asthma Mice Models

2021 ◽  
Author(s):  
Yi-min Wang ◽  
Wen-juan Xu ◽  
Lin-li Xiang ◽  
Mei Ding ◽  
Jin-jin Zhang ◽  
...  
Keyword(s):  
Airway Inflammation ◽  
Airway Remodeling ◽  
Protective Role ◽  
Negative Control ◽  
Calcium Entry ◽  
Cell Counting ◽  
Airway Smooth Muscle Cells ◽  
Regulatory Factor ◽  
Store Operated Calcium Entry

Background: Store-operated calcium entry (SOCE) is involved in the pathogenesis of airway inflammation and remodeling in asthma. Store-operated calcium entry-associated regulatory factor (SARAF) can down-regulate SOCE. Objective: We sought to investigate the role of SARAF in the regulation of airway inflammation and remodeling in asthma mice models, as well as in the functional regulation of human airway smooth muscle cells (hASMCs). Methods: Balb/c mice were sensitized and challenged with ovalbumin to establish the asthma mice models. Mice were transfected with lentivirus, which expressed the SARAF gene + GFP or the negative control gene + GFP. Airway resistance was measured with the animal pulmonary function system. Airway inflammation and remodeling were evaluated via histological staining. In vitro cultured hASMCs were transfected with scrambled small interfering RNA(siRNA) or SARAF-specific siRNA respecitvely. The proliferation, migration rate, hypertrophy and SOCE activity of hASMCs were examined with cell counting kit 8, wound healing test, bright field imaging and Ca2+ fluorescence imaging, respectively. SARAF expression was measured by quantitative real-time-PCR. Results: Asthma mice models showed decreased SARAF mRNA expression in the lungs. SARAF overexpression attenuated airway inflammation, resistance and also remodeling. Downregulation of SARAF expression with siRNA promoted the proliferation, migration, hypertrophy and SOCE activity in hASMCs. Conclusions: SARAF plays a protective role against airway inflammation and remodeling in asthma mice models by blunting SOCE; SARAF may also be a functional regulating factor of hASMCs.

scholarly journals Calcium Sensors STIM1 and STIM2 Regulate Different Calcium Functions in Cultured Hippocampal Neurons

2021 ◽  
Vol 12 ◽  
Author(s):  
Liliya Kushnireva ◽  
Eduard Korkotian ◽  
Menahem Segal
Keyword(s):  
Dendritic Spines ◽  
Hippocampal Neurons ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Plastic Properties ◽  
Calcium Sensors ◽  
Central Neurons ◽  
Transient Rise ◽  
Store Operated Calcium Entry ◽  
Adult Neuron

There are growing indications for the involvement of calcium stores in the plastic properties of neurons and particularly in dendritic spines of central neurons. The store-operated calcium entry (SOCE) channels are assumed to be activated by the calcium sensor stromal interaction molecule (STIM)which leads to activation of its associated Orai channel. There are two STIM species, and the differential role of the two in SOCE is not entirely clear. In the present study, we were able to distinguish between transfected STIM1, which is more mobile primarily in young neurons, and STIM2 which is less mobile and more prominent in older neurons in culture. STIM1 mobility is associated with spontaneous calcium sparks, local transient rise in cytosolic [Ca2+]i, and in the formation and elongation of dendritic filopodia/spines. In contrast, STIM2 is associated with older neurons, where it is mobile and moves into dendritic spines primarily when cytosolic [Ca2+]i levels are reduced, apparently to activate resident Orai channels. These results highlight a role for STIM1 in the regulation of [Ca2+]i fluctuations associated with the formation of dendritic spines or filopodia in the developing neuron, whereas STIM2 is associated with the maintenance of calcium entry into stores in the adult neuron.

scholarly journals Comparison of protein synthesis and degradation in incubated and perfused muscle

1983 ◽  
Vol 212 (3) ◽  
pp. 649-653 ◽  
Author(s):  
A S Clark ◽  
W E Mitch
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Insulin Treatment ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Muscle Protein Degradation ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Rates of muscle protein synthesis and degradation measured in the perfused hindquarter were compared with those in incubated epitrochlearis muscles. With fed or starved mature rats, results without insulin treatment were identical. With insulin treatment, protein synthesis in perfused hindquarters was greater, though protein degradation was the same. Thus rates of muscle protein degradation estimated by these two methods in vitro correspond closely.

Glutamate Release by Osteoblasts in the Presence of Ionic Products from Bioactive Glass 60S

2005 ◽  
Vol 284-286 ◽  
pp. 537-540
Author(s):  
Patricia Valério ◽  
C.C.P. Mendes ◽  
Marivalda Pereira ◽  
Alfredo Goes ◽  
M. Fatima Leite
Keyword(s):  
Bioactive Glass ◽  
Calcium Channel ◽  
Intracellular Calcium ◽  
Subcellular Distribution ◽  
Glutamate Release ◽  
Calcium Entry ◽  
The Other ◽  
Inositol Triphosphate ◽  
Type I ◽  
Type Ii

Osteoblasts constitutively release glutamate and this release appears to be regulated by calcium entry. In this work we investigated if the bioactive glass with 60% of silicon (BG60S) could alter glutamate release by osteoblasts. We demonstrated that osteoblasts incubated with medium containing ionic products from the dissolution of BG60S showed lower release of glutamate when compared to control. Since intracellular calcium (Cai 2+) increase is required for glutamate release we investigated the subcellular distribution of the calcium channel inositol triphosphate receptors (InsP3Rs) in the presence of BG60S compared to control. We found that the type-III InsP3R was not expressed in osteoblast, while the type-II InsP3R was expressed mainly in the cytosol. We also found that the expression of type-II InsP3R decreased in BG60S treated osteoblasts compared to control. On the other hand, we found that the type-I InsP3R was expressed mainly in the nucleus and its expression increased in the presence of the biomaterial.

Protein metabolism and gene expression in skeletal muscle of critically ill patients with sepsis

2011 ◽  
Vol 122 (3) ◽  
pp. 133-142 ◽  
Author(s):  
Maria Klaude ◽  
Maiko Mori ◽  
Inga Tjäder ◽  
Thomas Gustafsson ◽  
Jan Wernerman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Degradation ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Proteolytic Enzyme ◽  
Muscle Wasting ◽  
Muscle Protein ◽  
Synthesis Rate ◽  
Normal Muscle ◽  
Enzyme Systems

Muscle wasting negatively affects morbidity and mortality in critically ill patients. This progressive wasting is accompanied by, in general, a normal muscle PS (protein synthesis) rate. In the present study, we investigated whether muscle protein degradation is increased in critically ill patients with sepsis and which proteolytic enzyme systems are involved in this degradation. Eight patients and seven healthy volunteers were studied. In vivo muscle protein kinetics was measured using arteriovenous balance techniques with stable isotope tracers. The activities of the major proteolytic enzyme systems were analysed in combination with mRNA expression of genes related to these proteolytic systems. Results show that critically ill patients with sepsis have a variable but normal muscle PS rate, whereas protein degradation rates are dramatically increased (up to 160%). Of the major proteolytic enzyme systems both the proteasome and the lysosomal systems had higher activities in the patients, whereas calpain and caspase activities were not changed. Gene expression of several genes related to the proteasome system was increased in the patients. mRNA levels of the two main lysosomal enzymes (cathepsin B and L) were not changed but, conversely, genes related to calpain and caspase had a higher expression in the muscles of the patients. In conclusion, the dramatic muscle wasting seen in critically ill patients with sepsis is due to increased protein degradation. This is facilitated by increased activities of both the proteasome and lysosomal proteolytic systems.

A proinflammatory tumor that activates protein degradation sensitizes rats to catabolic effects of endotoxin

2005 ◽  
Vol 289 (4) ◽  
pp. E527-E533 ◽  
Author(s):  
Michelle L. Mackenzie ◽  
Nathalie Bedard ◽  
Simon S. Wing ◽  
Vickie E. Baracos
Keyword(s):  
Protein Degradation ◽  
Nitrogen Balance ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Ring Finger ◽  
Whole Body ◽  
Proteolytic Pathway ◽  
Before And After ◽  
Muscle Protein Degradation

Chronic or acute inflammation may participate in the etiology of cancer cachexia. To investigate the interaction between tumor and a secondary inflammatory stimulus on muscle wasting, rats with and without tumors (Yoshida ascites hepatoma) received low doses of endotoxin (LPS, 400 μg/kg sc) or saline. Nitrogen balance was measured 24 h before and after LPS/saline. Epitrochlearis muscle was used to measure in vitro protein metabolism, and gastrocnemius muscle was used for quantification of the mRNA for components of the ubiquitin proteolytic pathway. The YAH reduced muscle mass ( P = 0.002), increased muscle protein degradation ( P = 0.042), and elevated mRNA expression of components of the ubiquitin proteolytic pathway ( P < 0.01) including ubiquitin, ubiquitin-conjugating enzyme E214k, and ubiquitin ligases muscle RING Finger 1 and atrogin-1. Although the selected low dose of LPS had no impact on protein metabolism in control rats, LPS in rats bearing YAH caused weight loss ( P = 0.0007), lowered nitrogen balance ( P = <0.0001), and increased muscle protein degradation ( P = 0.0336). In conclusion, the presence of a tumor can potentiate whole body and muscle-specific catabolic losses of protein in response to a stimulus that is not catabolic in healthy animals. This effect might be dependent on the inflammatory nature of the tumor.

scholarly journals Polyphenol-Enriched Plum Extract Enhances Myotubule Formation and Anabolism while Attenuating Colon Cancer-induced Cellular Damage in C2C12 Cells

Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1077 ◽  
Author(s):  
Faten A. Alsolmei ◽  
Haiwen Li ◽  
Suzette L. Pereira ◽  
Padmavathy Krishnan ◽  
Paul W. Johns ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Cancer Cells ◽  
Total Protein ◽  
Muscle Wasting ◽  
Muscle Protein ◽  
C2c12 Cells ◽  
Cellular Damage ◽  
Myoblast Differentiation ◽  
Colon 26

Preventing muscle wasting in certain chronic diseases including cancer is an ongoing challenge. Studies have shown that polyphenols derived from fruits and vegetables shows promise in reducing muscle loss in cellular and animal models of muscle wasting. We hypothesized that polyphenols derived from plums (Prunus domestica) could have anabolic and anti-catabolic benefits on skeletal muscle. The effects of a polyphenol-enriched plum extract (PE60) were evaluated in vitro on C2C12 and Colon-26 cancer cells. Data were analyzed using a one-way ANOVA and we found that treatment of myocytes with plum extract increased the cell size by ~3-fold (p < 0.05) and stimulated myoblast differentiation by ~2-fold (p < 0.05). Plum extract induced total protein synthesis by ~50% (p < 0.05), reduced serum deprivation-induced total protein degradation by ~30% (p < 0.05), and increased expression of Insulin-Like Growth Factor-1 (IGF-1) by ~2-fold (p < 0.05). Plum extract also reduced tumor necrosis factor α (TNFα)-induced nuclear factor κB (NFκB) activation by 80% (p < 0.05) in A549/NF-κB-luc cells. In addition, plum extract inhibited the growth of Colon-26 cancer cells, and attenuated cytotoxicity in C2C12 myoblasts induced by soluble factors released from Colon-26 cells. In conclusion, our data suggests that plum extract may have pluripotent health benefits on muscle, due to its demonstrated ability to promote myogenesis, stimulate muscle protein synthesis, and inhibit protein degradation. It also appears to protect muscle cell from tumor-induced cytotoxicity.

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