Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology
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Cell. Physiol. Biochem. · Jan 2012
Lycorine, a candidate for the control of period length in mammalian cells.
Plants of the Amaryllidaceae family have been used as therapeutic agents against CNS related maladies such as Alzheimer's disease. The known primary alkaloid constituents have significant biological activity. We identified the Lycoris alkaloids lycorine and lycoricidinol from Amaryllidaceae using a real-time reporter gene assay system based on NIH3T3 cells. ⋯ Although one of its major activities is the inhibition of protein synthesis, lycorine induced dose-dependent period elongation regardless of the presence of cycloheximide and moreover, cycloheximide, itself did not affect period length, suggesting that lycorine dose-dependently extends the circadian period by a mechanism other than translational inhibition. Real-time RT-PCR showed that lycorine enhanced RORα and Bmal1 transcription, and exogenous expression and knockdown of Bmal1 also caused long and short periods, respectively, thus confirming the phenotype indicated by lycorine. These data indicate that lycorine and lycoricidinol modulate Bmal1 transcription and the circadian period, and also suggest that Lycoris alkaloids are novel contributors to the control of period length in mammalian cells.
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Cell. Physiol. Biochem. · Jan 2010
ReviewVascular barrier regulation by PAF, ceramide, caveolae, and NO - an intricate signaling network with discrepant effects in the pulmonary and systemic vasculature.
Increased endothelial permeability and vascular barrier failure are hallmarks of inflammatory responses in both the pulmonary and the systemic circulation. Platelet-activating factor (PAF) has been implicated as an important lipid mediator in the formation of pulmonary and extrapulmonary edema. Ostensibly, the PAF-induced signaling pathways in endothelial cells utilize similar structures and molecules including acid sphingomyelinase, ceramide, caveolae, endothelial nitric oxide synthase, and nitric oxide, in pulmonary and systemic microvessels. ⋯ By confronting seemingly discrepant findings from the literature, we reconstruct the differential signaling pathways by which PAF regulates edema formation in the systemic and the pulmonary vascular bed, and trace this dichotomy from the level of myosin light chain kinase via the regulation of endothelial nitric oxide synthase and sphingomyelinase signaling to the level of caveolar trafficking. Here, we propose that PAF regulates vascular barrier function in individual organs by opposing signaling pathways that culminate in increased respectively decreased nitric oxide synthesis in the systemic and the pulmonary endothelium. The present review may provide a physiological explanation for the overall disappointing results of previous pharmacological strategies in conditions of generalized barrier failure such as sepsis, and instead advertises the development of organ-specific interventions by targeting the individual composition or trafficking of endothelial caveolae.
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Cell. Physiol. Biochem. · Jan 2010
Differential effects of hypoxic stress in alveolar epithelial cells and microvascular endothelial cells.
Under hypoxic conditions eukaryotic cells and tissues undergo adaptive responses involving glycolysis, angiogenesis, vasoconstriction and inflammation. The underlying molecular mechanisms are not yet fully elucidated and are most likely cell and tissue specific. In the lung, alveolar epithelial cells and microvascular endothelial cells are highly sensitive to hypoxia and together orchestrate a rapid and sustained adaptive response. ⋯ These data reveal that both cell types exhibit an adaptive response to hypoxia but alveolar epithelial cells are generally more sensitive. ET-1 was oppositely regulated by decreased oxygen tensions in the investigated cell types. The present study further elucidates the adaptive molecular mechanisms in pulmonary hypoxia and demonstrates cell specific responses.
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Cell. Physiol. Biochem. · Jan 2010
Gensenoside Rg3 inhibits hypoxia-induced VEGF expression in human cancer cells.
The ginsenoside Rg3 (Rg3) inhibits xenograft growth and angiogenesis in tumors mainly via down-regulates VEGF expression. This study was designed to investigate the mechanisms by which Rg3 down-regulates VEGF expression. ⋯ Rg3 targets hypoxia-induced multiple signaling pathways to down-regulate VEGF expression in cancer cells. These actions may contribute to the overall efficacy of Rg3 against tumor angiogenesis and growth.
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Cell. Physiol. Biochem. · Jan 2010
Panax notoginseng saponins potentiate osteogenesis of bone marrow stromal cells by modulating gap junction intercellular communication activities.
The Chinese medicinal herb, Panax notoginseng, has long been used to treat bone fractures and Panax notoginseng saponins (PNS) could promote bone formation. We investigated the effects of PNS on gap junction intercellular communication (GJIC) and osteogenesis-associated genes in rat bone marrow stromal cells (BMSCs). ⋯ Our findings indicate that PNS could promote osteogenesis of BMSCs by targeting osteogenesis-associated genes, which could be mediated by their actions on GJIC.