Effects of olanzapine on glucose transport, proliferation and survival in C2C12 myoblasts

Tulipano, Giovanni; Spano, PierFranco

doi:10.1016/j.mce.2008.04.010

Cited by 14 publications

(11 citation statements)

References 34 publications

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“…In control experiments, insulin stimulated uptake to a moderate degree, as noted by others (Iwata et al, 2009; Tulipano et al, 2008). As expected cytochalasin B (a cell trafficking and GLUT-4 translocation inhibitor) and LY294002 (a PI3K inhibitor) reversed insulin mediated uptake (Fig.…”

Section: Resultssupporting

confidence: 82%

Foxo/Atrogin induction in human and experimental myositis

Lee

Rocnik

et al. 2012

Neurobiology of Disease

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Skeletal muscle atrophy can occur rapidly in various fasting, cancerous, systemic inflammatory, deranged metabolic or neurogenic states. The ubiquitin ligase Atrogin-1 (MAFbx) is induced in animal models of these conditions, causing excessive myoprotein degradation. It is unknown if Atrogin upregulation also occurs in acquired human myositis. Intracellular β-amyloid (Aβi), phosphorylated neurofilaments, scattered in-filtrates and atrophy involving selective muscle groups characterize human sporadic Inclusion Body Myositis (sIBM). In Polymyositis (PM), inflammation is more pronounced and atrophy is symmetric and proximal. IBM and PM share various inflammatory markers. We found that forkhead family transcription factor Foxo3A is directed to the nucleus and Atrogin-1 transcript is increased in both conditions. Expression of Aβ in transgenic mice and differentiated C2C12 myotubes was sufficient to upregulate Atrogin-1 mRNA and cause atrophy. Aβi reduces levels of p-Akt and downstream p-Foxo3A, resulting in Foxo3A translocation and Atrogin-1 induction. In a mouse model of autoimmune myositis, cellular inflammation alone was associated with similar Foxo3A and Atrogin changes. Thus, either Aβi accumulation or cellular immune stimulation may independently drive muscle atrophy in sIBM and PM, respectively, through pathways converging on Foxo and Atrogin-1. In sIBM it is additionally possible that both mechanisms synergize.

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Section: Resultssupporting

confidence: 82%

Foxo/Atrogin induction in human and experimental myositis

Lee

Rocnik

et al. 2012

Neurobiology of Disease

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“…1a). We checked unspecific drug toxicity by using Trypan Blue exclusion assay, an index of cell necrosis, as described [27]. AICAR (0.5 mM) or Compound C (2 lM) did not affect the cell membrane permeability to Trypan Blue compared with control cells (data not shown).…”

Section: Resultsmentioning

confidence: 99%

“…After centrifugation, the resulting supernatants were subjected to Western blotting. The exhaustive description of the methods have been reported previously [27]. Gel-Pro analyzer 3.1 software was used to quantify protein bands detected on western blots.…”

Section: Western Blot Analysismentioning

confidence: 99%

AMP-activated protein kinase regulates normal rat somatotroph cell function and growth of rat pituitary adenomatous cells

et al. 2011

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AMP-activated protein kinase (AMPK) is activated under conditions that deplete cellular ATP and elevate AMP levels such as glucose deprivation and hypoxia. The AMPK system is primarily thought of as a regulator of metabolism and cell proliferation. Little is known about the regulation and the effects of AMPK in somatotroph cells. We present results from "in vitro" studies showing that AMPK activity has a role in regulating somatotroph function in normal rat pituitary and is a promising target for the development of new pharmacological treatments affecting cell proliferation and viability of pituitary adenomatous cells. In parallel, we show "in vivo" data obtained in the rat suggesting that AMPK is an intracellular transducer that may play a role in mediating the effects of the pharmacological treatment with dexamethasone on somatotrophs. In rat pituitary cell cultures, the AMP analog AICAR induced a rapid and clear-cut activation of AMPK. AICAR decreased GH release and total cellular GH content. An appropriate level of AMPK activation was essential for GH3 adenomatous cells. Remarkably, over-activation by AICAR induced apoptosis of GH3 whereas the AMPK inhibitor compound C was more effective at reducing cell proliferation. The role of endocrine or paracrine factors in regulating AMPK phosphorylation and activity in GH3 cells has been also studied. As to "in vivo" studies, western blot analysis revealed a significant decrease of phosphorylated AMPK alpha-subunit in pituitary homogenates of DEX-treated rats versus controls, suggesting reduced AMPK activity. In conclusion, our studies showed that AMPK has a role in regulating somatotroph function in normal rat pituitary and proliferation of pituitary adenomatous cells.

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“…Other studies have shown GLUT4 enhancement under different concentrations of cinnamon extract or dihydrocinnamic acid (DHH105), a derivative of cinnamon, on GLUT4 content in animal adipose tissue [17] or 3T3-L1 cell line, a good model for studding fat tissue metabolism [14]. But muscular tissue is the most important site for glucose metabolism which uses more than 75 % of body glucose expenditure under insulin impact [18][19][20][21]. As the rate limiting step of blood glucose level expenditure is regulated by GLUT4 glycoprotein presence in the cytoplasmic membrane [22,23], the objective of current study was to investigate the effect of cinnamon water extract on GLUT4 contents of cytoplasmic membrane (CM) and nuclear/endoplasmic (N/ER) reticulum fractions of differentiated C2C12 myotubes.…”

Section: Introductionmentioning

confidence: 99%

Hydro-Alcoholic Cinnamon Extract, Enhances Glucose Transporter Isotype-4 Translocation from Intracellular Compartments into the Cytoplasmic Membrane of C2C12 Myotubes

et al. 2012

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Cinnamon has been used as an anti-diabetic agent for centuries but only in recent few years its mechanism of action has been under investigation. Previous studies showed that cinnamon might exert its anti-diabetic effect via increasing glucose transporter isotype-4 (GLUT4) gene and glycoprotein contents in fat cells. To study if hydro-alcoholic cinnamon extract (HACE) enhances GLUT4 translocation from intracellular compartments of nuclear or endoplasmic reticulum membranes (N/ER) into the cytoplasmic membrane (CM). C2C12 myoblastic cell line were seeded in DMEM plus 20 % FBS and differentiated to myotubes using 2 % horse serum. After myotubes formation, 100 or 1,000 lg/ml HACE, as intervention, and as control 1 % DMSO were added for 3 h. Cells were washed and homogenized followed by ultracentrifuge fractionation, protein separation by SDS-PAGE and GLUT4 detection using semi-quantitative Western blotting. Data analysis was done by two-independent samples t test for comparison of mean ± SD of GLUT4 percent in categories. GLUT4 contents were higher in CM of groups 100 and 1,000 lg/ml HACE and lower in 1 % DMSO treated myotubes (CI = 0.95, P \ 0.05). For N/ER reverse results were obtained (CI = 0.95, P \ 0.05). As our results have shown HACE induces GLUT4 translocation from intra-cell into cell surface. We conclude that cinnamon maybe a choice of type-2 diabetes mellitus treatment because its extract enhances GLUT4 contents in CM where it facilitates glucose entrance into the cell. However it is necessary to trace the signaling pathways which are activated by HACE in muscular tissue.

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Effects of olanzapine on glucose transport, proliferation and survival in C2C12 myoblasts

Cited by 14 publications

References 34 publications

Foxo/Atrogin induction in human and experimental myositis

Foxo/Atrogin induction in human and experimental myositis

AMP-activated protein kinase regulates normal rat somatotroph cell function and growth of rat pituitary adenomatous cells

Hydro-Alcoholic Cinnamon Extract, Enhances Glucose Transporter Isotype-4 Translocation from Intracellular Compartments into the Cytoplasmic Membrane of C2C12 Myotubes

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