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Sparks L.M.,Pennington Biomedical Research Center | Sparks L.M.,Maastricht University | Moro C.,Pennington Biomedical Research Center | Moro C.,University Paul Sabatier | And 8 more authors.
PLoS ONE | Year: 2011

Objective: Disturbances in lipid metabolism are strongly associated with insulin resistance and type 2 diabetes (T2D). We hypothesized that activation of cAMP/PKA and calcium signaling pathways in cultured human myotubes would provide further insight into regulation of lipid storage, lipolysis, lipid oxidation and insulin responsiveness. Methods: Human myoblasts were isolated from vastus lateralis, purified, cultured and differentiated into myotubes. All cells were incubated with palmitate during differentiation. Treatment cells were pulsed 1 hour each day with forskolin and ionomycin (PFI) during the final 3 days of differentiation to activate the cAMP/PKA and calcium signaling pathways. Control cells were not pulsed (control). Mitochondrial content, 14C lipid oxidation and storage were measured, as well as lipolysis and insulin-stimulated glycogen storage. Myotubes were stained for lipids and gene expression measured. Results: PFI increased oxidation of oleate and palmitate to CO2 (p<0.001), isoproterenol-stimulated lipolysis (p = 0.01), triacylglycerol (TAG) storage (p<0.05) and mitochondrial DNA copy number (p = 0.01) and related enzyme activities. Candidate gene and microarray analysis revealed increased expression of genes involved in lipolysis, TAG synthesis and mitochondrial biogenesis. PFI increased the organization of lipid droplets along the myofibrillar apparatus. These changes in lipid metabolism were associated with an increase in insulin-mediated glycogen storage (p<0.001). Conclusions: Activation of cAMP/PKA and calcium signaling pathways in myotubes induces a remodeling of lipid droplets and functional changes in lipid metabolism. These results provide a novel pharmacological approach to promote lipid metabolism and improve insulin responsiveness in myotubes, which may be of therapeutic importance for obesity and type 2 diabetes. © 2011 Sparks et al. Source


Fedotcheva T.A.,Russian National Research Medical University | Shirokikh K.E.,Russian National Research Medical University | Matyushin A.I.,Russian National Research Medical University | Rzheznikov V.M.,Institute of Experimental Endocrinology | And 2 more authors.
Biophysics (Russian Federation) | Year: 2015

In order to determine the cytotoxic or cytoprotective effect of the synthetic isoflavonoid genistein, we studied its effect on HeLa tumor cells, which contain estrogen alpha receptors and do not contain estrogen beta receptors. It was shown that the genistein concentration (IC50 = 0.2 mM) at which the half maximal inhibition of the HeLa cell viability is achieved is ten times higher than the concentrations of tamoxifen and cisplatin, which are reference agents with a cytotoxic effect. At micromolar concentrations (0.1–10 µM) genistein decreased the cytotoxic effects of cisplatin and tamoxifen. We found the reduced Bax mRNA expression and increased Bcl-2 mRNA expression during incubation of the cells with genistein, which also indicates its cytoprotective anti-apoptotic effect. Genistein, even in high concentrations, had no effect on the membrane potential and calcium capacity of isolated mitochondria and did not activate the opening of the Ca2+-induced mitochondrial pore. Thus, the data show a protective effect of the isoflavonoid genistein on tumor cells. © 2015, Pleiades Publishing, Inc. Source


Smirnova Z.S.,Blokhin Oncological Research Center | Rzheznikov V.M.,Institute of Experimental Endocrinology | Tolkachev V.N.,Blokhin Oncological Research Center | Borisova L.M.,Blokhin Oncological Research Center | And 6 more authors.
Eksperimental'naya i Klinicheskaya Farmakologiya | Year: 2014

Cytestrole acetate (CA), in the structure of which the steroidal antiestrogen component is associated with bis-β-cloroethylamino group, exhibits a strong cytotoxic activity against hormone-dependent cancer cell lines (CaOV, HeLa, MCF-7). In doxorubicin-resistant MCF-7 cells, CA potentiates the cytotoxic effect of etoposide and doxorubicin, and the IC50 for CA in these cells is 40 times lower than that for tamoxifen (TAM). In transplantable mice breast adenocarcinoma Ca-755, the therapeutic CA dose is 25 mg/kg when administered subcutaneously in oil solution for 5 days. On the DMBA-induced mammary tumors in rats, CA injected subcutaneously led to partial regressions 4 weeks after treatment in 75% of test rats, whereas TAM produced this effect in 43% of rats. Among various drug forms of CA, the most active were oil solution of CA in gelatin capsules for oral use and liposomal emulsion for intravenous administration, since these forms exhibited the highest values of Ca-755 tumor growth inhibition index (TGI = 97-98%). Source


Zatkova M.,Comenius University | Bakos J.,Comenius University | Bakos J.,Institute of Experimental Endocrinology | Hodosy J.,Comenius University | And 2 more authors.
Biomedical Papers | Year: 2016

Background. Recent research has produced an explosion of experimental data on the complex neurobiological mechanisms of developmental disorders including autism. Animal models are one approach to studying the phenotypic features and molecular basis of autism. In this review, we describe progress in understanding synaptogenesis and alterations to this process with special emphasis on the cell adhesion molecules and scaffolding proteins implicated in autism. Genetic mouse model experiments are discussed in relation to alterations to selected synaptic proteins and consequent behavioral deficits measured in animal experiments. Methods. Pubmed databases were used to search for original and review articles on animal and human clinical studies on autism. Results. The cell adhesion molecules, neurexin, neurolignin and the Shank family of proteins are important molecular targets associated with autism. Conclusion. The heterogeneity of the autism spectrum of disorders limits interpretation of information acquired from any single animal model or animal test. We showed synapse-specific/ model-specific defects associated with a given genotype in these models. Characterization of mouse models with genetic variations may help study the mechanisms of autism in humans. However, it will be necessary to apply new analytic paradigms in using genetically modified mice for understanding autism etiology in humans. Further studies are needed to create animal models with mutations that match the molecular and neural bases of autism. © 2016, PALACKY UNIV. All rights reserved. Source


Bohnekamp J.,University of Leipzig | Boselt I.,University of Leipzig | Saalbach A.,University of Leipzig | Tonjes A.,University of Leipzig | And 11 more authors.
Biochemical and Biophysical Research Communications | Year: 2010

Chemokine receptors control leukocyte chemotaxis and cell-cell communication but have also been associated with pathogen entry. GPR33, an orphan member of the chemokine-like receptor family, is a pseudogene in most humans. After the appearance of GPR33 in first mammalian genomes, this receptor underwent independent pseudogenization in humans, other hominoids and some rodent species. It was speculated that a likely cause of GPR33 inactivation was its interplay with a rodent-hominoid-specific pathogen. Simultaneous pseudogenization in several unrelated species within the last 1 million years (myr) caused by neutral drift appears to be very unlikely suggesting selection on the GPR33 null-allele. Although there are no signatures of recent selection on human GPR33 we found a significant increase in the pseudogene allele frequency in European populations when compared with African and Asian populations. Because its role in the immune system was still hypothetical expression analysis revealed that GPR33 is highly expressed in dendritic cells (DC). Murine GPR33 expression is regulated by the activity of toll-like receptors (TLR) and AP-1/NF-κB signaling pathways in cell culture and in vivo. Our data indicate an important role of GPR33 function in innate immunity which became dispensable during human evolution most likely due to past or balancing selection. © 2010 Elsevier Inc. All rights reserved. Source

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