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Sample records for cells control growth

  1. Bacterial cell curvature through mechanical control of cell growth

    PubMed Central

    Cabeen, Matthew T; Charbon, Godefroid; Vollmer, Waldemar; Born, Petra; Ausmees, Nora; Weibel, Douglas B; Jacobs-Wagner, Christine

    2009-01-01

    The cytoskeleton is a key regulator of cell morphogenesis. Crescentin, a bacterial intermediate filament-like protein, is required for the curved shape of Caulobacter crescentus and localizes to the inner cell curvature. Here, we show that crescentin forms a single filamentous structure that collapses into a helix when detached from the cell membrane, suggesting that it is normally maintained in a stretched configuration. Crescentin causes an elongation rate gradient around the circumference of the sidewall, creating a longitudinal cell length differential and hence curvature. Such curvature can be produced by physical force alone when cells are grown in circular microchambers. Production of crescentin in Escherichia coli is sufficient to generate cell curvature. Our data argue for a model in which physical strain borne by the crescentin structure anisotropically alters the kinetics of cell wall insertion to produce curved growth. Our study suggests that bacteria may use the cytoskeleton for mechanical control of growth to alter morphology. PMID:19279668

  2. TOR and paradigm change: cell growth is controlled.

    PubMed

    Hall, Michael N

    2016-09-15

    This year marks the 25th anniversary of the discovery of target of rapamycin (TOR), a highly conserved kinase and central controller of cell growth. In this Retrospective, I briefly describe the discovery of TOR and the subsequent elucidation of its cellular role. I place particular emphasis on an article by Barbet et al. from 1996, the first suggesting that TOR controls cell growth in response to nutrients.

  3. TOR and paradigm change: cell growth is controlled

    PubMed Central

    Hall, Michael N.

    2016-01-01

    This year marks the 25th anniversary of the discovery of target of rapamycin (TOR), a highly conserved kinase and central controller of cell growth. In this Retrospective, I briefly describe the discovery of TOR and the subsequent elucidation of its cellular role. I place particular emphasis on an article by Barbet et al. from 1996, the first suggesting that TOR controls cell growth in response to nutrients. PMID:27634743

  4. Control of cell cycle and cell growth by molecular chaperones.

    PubMed

    Aldea, Martí; Garí, Eloi; Colomina, Neus

    2007-11-01

    Cells adapt their size to both intrinsic and extrinsic demands and, among them, those that stem from growth and proliferation rates are crucial for cell size homeostasis. Here we revisit mechanisms that regulate cell cycle and cell growth in budding yeast. Cyclin Cln3, the most upstream activator of Start, is retained at the endoplasmic reticulum in early G(1) and released by specific chaperones in late G(1) to initiate the cell cycle. On one hand, these chaperones are rate-limiting for release of Cln3 and cell cycle entry and, on the other hand, they are required for key biosynthetic processes. We propose a model whereby the competition for specialized chaperones between growth and cycle machineries could gauge biosynthetic rates and set a critical size threshold at Start.

  5. Hormonal Control of Breast Cancer Cell Growth

    DTIC Science & Technology

    1997-09-01

    Roscovitine on the Proliferative Activity of 10 Human Breast Epithelial Cells Results 10 Discussion 13 Recommendations in Relation to the 16 Statement... roscovitine , that inhibits the kinase activity of cdc2/cyclin B, cdk2/cyclin A, and cdk2/cyclin E complexes (31, 36-38). Since it has been reported that... roscovitine prevents the cell cycle progression of mammalian cells at the GI/S and the and G2/M checkpoints and blocks the transactivation of cyclin A

  6. Hormonal Control of Breast Cancer Cell Growth.

    DTIC Science & Technology

    1998-09-01

    retinoblastoma (pRb) proteins (73) and by cyclin-dependent kinase inhibitors, such as roscovitine , that inhibits the kinase activity of cdc2/cyclin B...urothelial cancer cells MCF-7 and T24, respectively (82,83). The effect of hCG was compared with that of roscovitine , which is known to prevent the cell...dCTP (random primer labeling kit, GIBCO, BRL). Effect of Roscovitine and Resveratrol on the Proliferative Activity of Human Breast Epithelial Cells: MCF

  7. Global control of cell growth in fission yeast and its coordination with the cell cycle.

    PubMed

    Navarro, Francisco J; Weston, Louise; Nurse, Paul

    2012-12-01

    Cell growth is a fundamental process for every cell but its pleiotropic complexity makes it difficult to comprehend. Global aspects of cellular growth, like the overall determinants of growth rate are not well understood. Here we examine the cell growth pattern of the fission yeast Schizosaccharomyces pombe during the mitotic and meiotic cell cycles. We also explore recent findings illuminating aspects of cell size homeostasis and cell growth regulation, and propose that there are global controls over growth acting at the level of the cell. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Controlling mechanisms in directional growth of aggregated archaeal cells.

    PubMed

    Milkevych, Viktor; Batstone, Damien J

    2014-12-28

    Members of the family Methanosarcinaceae are important archaeal representatives due to their broad functionality, ubiquitous presence, and functionality in harsh environments. A key characteristic is their multicellular (packet) morphology represented by aggregates of spatially confined cells. This morphology is driven by directed growth of cells in confinement with sequential variation in growth direction. To further understand why spatially confined Methanosarcina cells (and in general, confined prokaryotes) change their direction of growth during consecutive growth-division stages, and how a particular cell senses its wall topology and responds to changes on it a theoretical model for stress dependent growth of aggregated archaeal cells was developed. The model utilizes a confined elastic shell representation of aggregated archaeal cell and is derived based on a work-energy principle. The growth law takes into account the fine structure of archaeal cell wall, polymeric nature of methanochondroitin layer, molecular-biochemical processes and is based on thermodynamic laws. The developed model has been applied to three typical configurations of aggregated cell in 3D. The developed model predicted a geometry response with delayed growth of aggregated archaeal cells explained from mechanistic principles, as well as continuous changes in direction of growth during the consecutive growth-division stages. This means that cell wall topology sensing and growth anisotropy can be predicted using simple cellular mechanisms without the need for dedicated cellular machinery.

  9. Dual control of cell growth by somatomedins and platelet-derived growth factor.

    PubMed Central

    Stiles, C D; Capone, G T; Scher, C D; Antoniades, H N; Van Wyk, J J; Pledger, W J

    1979-01-01

    Quiescent BALB/c 3T3 cells exposed briefly to a platelet-derived growth factor (PDGF) become "competent" to replicate their DNA but do not "progress" into S phase unless incubated with growth factors contained in platelet-poor plasma. Plasma from hypophysectomized rats is deficient in progression activity; it does not stimulate PDGF-treated competent cells to synthesize DNA, demonstrating that somatomedin C is required for progression. Various growth factors were tested for progression activity and competence activity by using BALB/c 3T3 tissue culture assays. Multiplication stimulating activity and other members of the somatomedin family of growth factors are (like somatomedin C) potent mediators of progression. Other mitogenic agents, such as fibroblast growth factor, are (like PDGF) potent inducers of competence. Growth factors with potent progression activity have little or no competence activity and vice versa. In contrast, simian virus 40 provides both competence and progression activity. Coordinate control of BALB/c 3T3 cell growth in vitro by competence factors and somatomedins may be a specific example of a common pattern of growth regulation in animal tissues. PMID:312500

  10. Peptide microarray patterning for controlling and monitoring cell growth.

    PubMed

    Lin, Edith; Sikand, Adhirath; Wickware, Jessica; Hao, Yubin; Derda, Ratmir

    2016-04-01

    The fate of cells is influenced by their microenvironment and many cell types undergo differentiation when stimulated by extracellular cues, such as soluble growth factors and the insoluble extracellular matrix (ECM). Stimulating differentiation by insoluble or "immobilized" cues is a particularly attractive method because it allows for the induction of differentiation in a spatially-defined cohort of cells within a larger subpopulation. To improve the design of de novo screening of such insoluble factors, we describe a methodology for producing high-density peptide microarrays suitable for extended cell culture and fluorescence microscopy. As a model, we used a murine mammary gland cell line (NMuMG) that undergoes epithelial to mesenchymal transition (EMT) in response to soluble transforming growth factor beta (TGF-β) and surface-immobilized peptides that target TGF-β receptors (TGFβRI/II). We repurposed a well-established DNA microarray printing technique to produce arrays of micropatterned surfaces that displayed TGFβRI/II-binding peptides and integrin binding peptides. Upon long-term culture on these arrays, only NMuMG cells residing on EMT-stimulating areas exhibited growth arrest and decreased E-cadherin expression. We believe that the methodology created in this report will aid the development of peptide-decorated surfaces that can locally stimulate defined cell surface receptors and control EMT and other well-characterized differentiation events. Scope of work: This manuscript aims to accelerate the development of instructive biomaterials decorated with specific ligands that target cell-surface receptors and induce specific differentiation of cells upon contact. These materials can be used for practical applications, such as fabricating synthetic materials for large scale, stem cell culture, or investigating differentiation and asymmetric division in stem cells. Specifically, in this manuscript, we repurposed a DNA microarray printer to produce

  11. Control of Cell Wall Extensibility during Pollen Tube Growth

    PubMed Central

    Hepler, Peter K.

    2013-01-01

    In this review, we address the question of how the tip-growing pollen tube achieves its rapid rate of elongation while maintaining an intact cell wall. Although turgor is essential for growth to occur, the local expansion rate is controlled by local changes in the viscosity of the apical wall. We focus on several different structures and underlying processes that are thought to be major participants including exocytosis, the organization and activity of the actin cytoskeleton, calcium and proton physiology, and cellular energetics. We think that the actin cytoskeleton, in particular the apical cortical actin fringe, directs the flow of vesicles to the apical domain, where they fuse with the plasma membrane and contribute their contents to the expanding cell wall. While pH gradients, as generated by a proton-ATPase located on the plasma membrane along the side of the clear zone, may regulate rapid actin turnover and new polymerization in the fringe, the tip-focused calcium gradient biases secretion towards the polar axis. The recent data showing that exocytosis of new wall material precedes and predicts the process of cell elongation provide support for the idea that the intussusception of newly secreted pectin contributes to decreases in apical wall viscosity and to cell expansion. Other prime factors will be the localization and activity of the enzyme pectin methyl-esterase, and the chelation of calcium by pectic acids. Finally, we acknowledge a role for reactive oxygen species in the control of wall viscosity. PMID:23770837

  12. Control of cell wall extensibility during pollen tube growth.

    PubMed

    Hepler, Peter K; Rounds, Caleb M; Winship, Lawrence J

    2013-07-01

    In this review, we address the question of how the tip-growing pollen tube achieves its rapid rate of elongation while maintaining an intact cell wall. Although turgor is essential for growth to occur, the local expansion rate is controlled by local changes in the viscosity of the apical wall. We focus on several different structures and underlying processes that are thought to be major participants including exocytosis, the organization and activity of the actin cytoskeleton, calcium and proton physiology, and cellular energetics. We think that the actin cytoskeleton, in particular the apical cortical actin fringe, directs the flow of vesicles to the apical domain, where they fuse with the plasma membrane and contribute their contents to the expanding cell wall. While pH gradients, as generated by a proton-ATPase located on the plasma membrane along the side of the clear zone, may regulate rapid actin turnover and new polymerization in the fringe, the tip-focused calcium gradient biases secretion towards the polar axis. The recent data showing that exocytosis of new wall material precedes and predicts the process of cell elongation provide support for the idea that the intussusception of newly secreted pectin contributes to decreases in apical wall viscosity and to cell expansion. Other prime factors will be the localization and activity of the enzyme pectin methyl-esterase, and the chelation of calcium by pectic acids. Finally, we acknowledge a role for reactive oxygen species in the control of wall viscosity.

  13. ERRα metabolic nuclear receptor controls growth of colon cancer cells.

    PubMed

    Bernatchez, Gérald; Giroux, Véronique; Lassalle, Thomas; Carpentier, André C; Rivard, Nathalie; Carrier, Julie C

    2013-10-01

    The estrogen-related receptor alpha (ERRα) is a nuclear receptor that acts primarily as a regulator of metabolic processes, particularly in tissues subjected to high-energy demand. In addition to its control of energy metabolism and mitochondrial biogenesis, ERRα has recently been associated with cancer progression. Notably, increased expression of ERRα has been shown in several cancerous tissues, including breast, ovary and colon. However, additional studies are required to gain insight into the action of ERRα in cancer biology, particularly in non-endocrine-related cancers. Therefore, using a short hairpin RNA-mediated approach, we investigated whether ERRα is required for the rapid growth of colon cancer cells and to maintain their neoplastic metabolic state. Results show that silencing ERRα significantly impaired colon cancer cell proliferation and colony formation in vitro as well as their in vivo tumorigenic capacity. A pronounced delay in G1-to-S cell cycle phase transition was observed in ERRα-depleted cells in association with reduced cyclin-dependent kinase 2 activity and hyperphosphorylated state of the retinoblastoma protein along with disturbed expression of several cell cycle regulators, including p15 and p27. Interestingly, ERRα-depleted HCT116 cells also displayed significant reduction in expression of a large set of key genes to glycolysis, tricarboxylic acid cycle and lipid synthesis. Furthermore, using (14)C isotope tracer analysis, ERRα depletion in colon cancer cells resulted in reduced glucose incorporation and glucose-mediated lipogenesis in these cells. These findings suggest that ERRα coordinates colon cancer cell proliferation and tumorigenic capacity with energy metabolism. Thus, ERRα could represent a promising therapeutic target in colon cancer.

  14. Developmental control of endocycles and cell growth in plants.

    PubMed

    Breuer, Christian; Ishida, Takashi; Sugimoto, Keiko

    2010-12-01

    Timely progression of the mitotic cell cycle is central for growth and development of plant organs. Many cell types in plants also enter an alternative cell cycle called the endoreduplication cycle or endocycle in which cells increase their ploidy through repeated rounds of chromosomal replication without cell divisions. The transition from the mitotic cycle into the endocycle often coincides with the initiation of cell expansion and cell differentiation, and strong correlations between final ploidy level and cell size have been reported in many plant species. Recent studies have begun to unveil how developmental signals modulate entry and exit of the endocycle through both transcriptional and post-transcriptional mechanisms. An increase in ploidy by endocycles is not an ultimate determinant of plant cell size and it is likely that it sets the maximum capacity for future cellular growth. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Maternal control of integument cell elongation and zygotic control of endosperm growth are coordinated to determine seed size in Arabidopsis.

    PubMed

    Garcia, Damien; Fitz Gerald, Jonathan N; Berger, Frédéric

    2005-01-01

    We use Arabidopsis thaliana as a model to investigate coordination of cell proliferation and cell elongation in the three components that develop side by side in the seed. Two of these, the embryo and its nurturing annex, the endosperm, are placed under zygotic control and develop within the seed integument placed under maternal control. We show that integument cell proliferation and endosperm growth are largely independent from each other. By contrast, prevention of cell elongation in the integument by the mutation transparent testa glabra2 (ttg2) restricts endosperm and seed growth. Conversely, endosperm growth controlled by the HAIKU (IKU) genetic pathway modulates integument cell elongation. Combinations of TTG2 defective seed integument with reduction of endosperm size by iku mutations identify integument cell elongation and endosperm growth as the primary regulators of seed size. Our results strongly suggest that a cross talk between maternal and zygotic controls represents the primary regulator of the coordinated control of seed size in Arabidopsis.

  16. Density-dependent regulation of growth of BSC-1 cells in cell culture: control of growth by serum factors.

    PubMed Central

    Holley, R W; Armour, R; Baldwin, J H; Brown, K D; Yeh, Y C

    1977-01-01

    BSC-1 cells grow slowly, to high cell density, in medium with 0.1% calf serum. An increase in the serum concentration increases both the growth rate of the cells and the final cell density. The serum can be replaced to some extent by epidermal growth factor (EGF). Initiation of DNA synthesis in BSC-1 cells that have spread into a "wound" in a crowded cell layer requires the addition of a trace of serum or EGF, if the cells have previously been deprived of serum. The binding of 125I-labeled EGF to low-density and high-density BSC-1 cells has been studied. Binding is faster to low-density cells. Cells at low cell density also bind much more EGF per cell than cells at high cell density. The fraction of bound 125I-labeled EGF that is present on the cell surface as intact EGF is larger at low than at high cell density. The results indicate that the number of available EGF receptors per cell decreases drastically as the cell density increases. It is suggested that a decrease in the number of available EGF receptor sites per cell, and the accompanying decrease in sensitivity of the cells to EGF, contributes to density-dependent regulation of growth of these cells. Images PMID:303774

  17. Size control: cell proliferation does not equal growth.

    PubMed

    Su, T T; O'Farrell, P H

    1998-09-24

    Division subdivides mass without increasing it. So one should not expect that an increase in cell division would make an organism bigger. Both classic and recent experiments confirm this simple rationale: altering proliferation produces normally sized body structures with either especially small or exceptionally large cells.

  18. Size control: Cell proliferation does not equal growth

    PubMed Central

    Su, Tin Tin; O’Farrell, Patrick H.

    2009-01-01

    Division subdivides mass without increasing it. So one should not expect that an increase in cell division would make an organism bigger. Both classic and recent experiments confirm this simple rationale: altering proliferation produces normally sized body structures with either especially small or exceptionally large cells. PMID:9768354

  19. Polarized Growth Controls Cell Shape and Bipolar Bud Site Selection in Saccharomyces cerevisiae

    PubMed Central

    Sheu, Yi-Jun; Barral, Yves; Snyder, Michael

    2000-01-01

    We examined the relationship between polarized growth and division site selection, two fundamental processes important for proper development of eukaryotes. Diploid Saccharomyces cerevisiae cells exhibit an ellipsoidal shape and a specific division pattern (a bipolar budding pattern). We found that the polarity genes SPA2, PEA2, BUD6, and BNI1 participate in a crucial step of bud morphogenesis, apical growth. Deleting these genes results in round cells and diminishes bud elongation in mutants that exhibit pronounced apical growth. Examination of distribution of the polarized secretion marker Sec4 demonstrates that spa2Δ, pea2Δ, bud6Δ, and bni1Δ mutants fail to concentrate Sec4 at the bud tip during apical growth and at the division site during repolarization just prior to cytokinesis. Moreover, cell surface expansion is not confined to the distal tip of the bud in these mutants. In addition, we found that the p21-activated kinase homologue Ste20 is also important for both apical growth and bipolar bud site selection. We further examined how the duration of polarized growth affects bipolar bud site selection by using mutations in cell cycle regulators that control the timing of growth phases. The grr1Δ mutation enhances apical growth by stabilizing G1 cyclins and increases the distal-pole budding in diploids. Prolonging polarized growth phases by disrupting the G2/M cyclin gene CLB2 enhances the accuracy of bud site selection in wild-type, spa2Δ, and ste20Δ cells, whereas shortening the polarized growth phases by deleting SWE1 decreases the fidelity of bipolar budding. This study reports the identification of components required for apical growth and demonstrates the critical role of polarized growth in bipolar bud site selection. We propose that apical growth and repolarization at the site of cytokinesis are crucial for establishing spatial cues used by diploid yeast cells to position division planes. PMID:10866679

  20. Control of Breast Tumor Cell Growth by Dietary Indoles

    DTIC Science & Technology

    1999-09-01

    trials as a cancer chemotherapeutic and preventive agent (15). Our working hypothesis was that 13C is converted in gastric acid to products that...Although the function of this gene product is poorly understood. NAK1/TR3 is the human homologue of the proteins encoded by the rat NGFI-B and mouse nur77...mediated by retinoic acid , growth factors, and phorbol esters (22). The immediate-early gene, Egr-1, produces a zinc finger protein involved in many

  1. Solvent engineering towards controlled grain growth in perovskite planar heterojunction solar cells.

    PubMed

    Rong, Yaoguang; Tang, Zhongjia; Zhao, Yufeng; Zhong, Xin; Venkatesan, Swaminathan; Graham, Harrison; Patton, Matthew; Jing, Yan; Guloy, Arnold M; Yao, Yan

    2015-06-28

    We report an effective solvent engineering process to enable controlled perovskite crystal growth and a wider window for processing uniform and dense methyl ammonium lead iodide (MAPbI3) perovskite films. Planar heterojunction solar cells fabricated with this method demonstrate hysteresis-free performance with a power conversion efficiency around 10%. The crystal structure of an organic-based Pb iodide intermediate phase is identified for the first time, which is critical in controlling the crystal growth and optimizing thin film morphology.

  2. Growth Control in Colon Epithelial Cells: Gadolinium Enhances Calcium-Mediated Growth Regulation

    PubMed Central

    Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K.

    2013-01-01

    Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1–5 µM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet. PMID:23008064

  3. Growth control in colon epithelial cells: gadolinium enhances calcium-mediated growth regulation.

    PubMed

    Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K; Varani, James

    2012-12-01

    Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1-5 μM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet.

  4. Growth control of budding yeast cells by oxygen-radical treatment

    NASA Astrophysics Data System (ADS)

    Ohta, Takayuki; Hashizume, Hiroshi; Ito, Masafumi; Takeda, Keigo; Hori, Masaru

    2013-09-01

    Microorganisms respond to stimuli or stresses such as chemicals, nutrition, pressure, heat and so on. Those stimuli lead to cell activation, inactivation or cell death, such as apoptosis and necrosis. Reactive oxygen species possibly affect cell growth as well as inactivation depending on stimuli. In this study, we investigated effects of oxygen-radical treatment on not only inactivation but also promoted/repressed cell growth of budding yeast by varying dose of atomic oxygen produced from an atmospheric-pressure oxygen radical source. Dose of atomic oxygen was estimated based on treatment time and oxygen flux. Cell growth was promoted with atomic oxygen between 0 and 2.1 ×1019 cm-2 dose of atomic oxygen. The treated cells were grown about 10 percent more proliferously than the control cells. Moreover, 64 percent of the treated cells to the control ones were inactivated at more than 4.2 ×1020 cm-2. These results, therefore, suggested that atomic-oxygen dose had a potential to control mitotic promotion and repression, and inactivation of yeast cell growth.

  5. Mycobacterium tuberculosis growth control by lung macrophages and CD8 cells from patient contacts.

    PubMed

    Carranza, Claudia; Juárez, Esmeralda; Torres, Martha; Ellner, Jerrold J; Sada, Eduardo; Schwander, Stephan K

    2006-01-15

    Healthy household contacts (HHCs) of patients with active pulmonary tuberculosis are exposed aerogenically to Mycobacterium tuberculosis (Mtb), thus permitting the study of protective local immunity. To assess alveolar macrophage (AM) and autologous blood CD4 and CD8 T-cell-mediated Mtb growth control in HHCs and healthy, unexposed community control subjects (CCs). AMs were infected with Mtb strains H(37)Ra and H(37)Rv at multiplicities of infection 0.1 and 1. Mtb colony-forming units were evaluated on Days 1, 4, and 7. CD8 T cells from HHCs in 1:1 cocultures with AMs significantly (p < 0.05) increased Mtb growth control by AMs. In CCs, no detectable contribution of CD8 T cells to Mtb growth control was observed. CD4 T cells did not increase Mtb growth control in HHCs or in CCs. IFN-gamma, nitric oxide, and tumor necrosis factor were determined as potential mediators of Mtb growth control in AMs and AM/CD8 and AM/CD4 cocultures. IFN-gamma production in AM/CD4 was twofold higher than that in AM/CD8 cocultures in both HHCs and CCs (p < 0.05). Nitric oxide production from AMs of HHCs increased on Days 4 and 7 and was undetectable in AMs from CCs. IFN-gamma and nitric acid concentrations and Mtb growth control were not correlated. Tumor necrosis factor levels were significantly increased in AM/CD8 cocultures from HHCs compared with AM/CD8 cocultures from CCs (p < 0.05). Aerogenic exposure to Mtb in HHCs leads to expansion of Mtb-specific effector CD8 T cells that limit Mtb growth in autologous AMs.

  6. Control of human glioma cell growth, migration and invasion in vitro by transforming growth factor beta 1.

    PubMed Central

    Merzak, A.; McCrea, S.; Koocheckpour, S.; Pilkington, G. J.

    1994-01-01

    Factors involved in the control of the biological properties of gliomas, the major form of brain tumour in man, are poorly documented. We investigated the role of transforming growth factor beta 1 (TGF-beta 1) in the control of proliferation of human glioma cell lines as well as normal human fetal brain cells. The data presented show that TGF-beta 1 exerts a growth-inhibitory action on both human fetal brain cells and three cell lines derived from human glioma of different grades of malignancy. In addition, this growth-inhibitory effect is dose dependent and serum independent. Since TGF-beta 1 is known to be involved in the control of cell migration during ontogenesis and oncogenesis, we investigated the role of this factor in the motile and invasive behaviour that characterises human gliomas in vivo. TGF-beta 1 was found to elicit a strong stimulation of migration and invasiveness of glioma cells in vitro. In combination with recent data showing an inverse correlation between TGF-beta 1 expression in human gliomas and survival, these findings may suggest that TGF-beta 1 plays an important role in the malignant progression of gliomas in man. A study of the molecular mechanisms involved in the antiproliferative action and the invasion-promoting action of TGF-beta 1 may help to identify new targets in therapy for brain tumours. A combined antiproliferative and anti-invasive therapy could be envisaged. Images Figure 3 PMID:8054266

  7. Control of growth and inflammatory response of macrophages and foam cells with nanotopography

    NASA Astrophysics Data System (ADS)

    Mohiuddin, Mohammed; Pan, Hsu-An; Hung, Yao-Ching; Huang, Guewha Steven

    2012-07-01

    Macrophages play an important role in modulating the immune function of the human body, while foam cells differentiated from macrophages with subsequent fatty streak formation play a key role in atherosclerosis. We hypothesized that nanotopography modulates the behavior and function of macrophages and foam cells without bioactive agent. In the present study, nanodot arrays ranging from 10- to 200-nm were used to evaluate the growth and function of macrophages and foam cells. In the quantitative analysis, the cell adhesion area in macrophages increased with 10- to 50-nm nanodot arrays compared to the flat surface, while it decreased with 100- and 200-nm nanodot arrays. A similar trend of adhesion was observed in foam cells. Immunostaining, specific to vinculin and actin filaments, indicated that a 50-nm surface promoted cell adhesion and cytoskeleton organization. On the contrary, 200-nm surfaces hindered cell adhesion and cytoskeleton organization. Further, based on quantitative real-time polymerase chain reaction data, expression of inflammatory genes was upregulated for the 100- and 200-nm surfaces in macrophages and foam cells. This suggests that nanodots of 100- and 200-nm triggered immune inflammatory stress response. In summary, nanotopography controls cell morphology, adhesions, and proliferation. By adjusting the nanodot diameter, we could modulate the growth and expression of function-related genes in the macrophages and foam cell system. The nanotopography-mediated control of cell growth and morphology provides potential insight for designing cardiovascular implants.

  8. Growth Kinetics of Suspended Microbial Cells: From Single-Substrate-Controlled Growth to Mixed-Substrate Kinetics

    PubMed Central

    Kovárová-Kovar, Karin; Egli, Thomas

    1998-01-01

    Growth kinetics, i.e., the relationship between specific growth rate and the concentration of a substrate, is one of the basic tools in microbiology. However, despite more than half a century of research, many fundamental questions about the validity and application of growth kinetics as observed in the laboratory to environmental growth conditions are still unanswered. For pure cultures growing with single substrates, enormous inconsistencies exist in the growth kinetic data reported. The low quality of experimental data has so far hampered the comparison and validation of the different growth models proposed, and only recently have data collected from nutrient-controlled chemostat cultures allowed us to compare different kinetic models on a statistical basis. The problems are mainly due to (i) the analytical difficulty in measuring substrates at growth-controlling concentrations and (ii) the fact that during a kinetic experiment, particularly in batch systems, microorganisms alter their kinetic properties because of adaptation to the changing environment. For example, for Escherichia coli growing with glucose, a physiological long-term adaptation results in a change in KS for glucose from some 5 mg liter−1 to ca. 30 μg liter−1. The data suggest that a dilemma exists, namely, that either “intrinsic” KS (under substrate-controlled conditions in chemostat culture) or μmax (under substrate-excess conditions in batch culture) can be measured but both cannot be determined at the same time. The above-described conventional growth kinetics derived from single-substrate-controlled laboratory experiments have invariably been used for describing both growth and substrate utilization in ecosystems. However, in nature, microbial cells are exposed to a wide spectrum of potential substrates, many of which they utilize simultaneously (in particular carbon sources). The kinetic data available to date for growth of pure cultures in carbon-controlled continuous culture

  9. Control of cell growth by the SCF and APC/C ubiquitin ligases

    PubMed Central

    Skaar, Jeffrey R.; Pagano, Michele

    2009-01-01

    The ubiquitin-proteasome system plays key roles in the control of cell growth. The cell cycle in particular is highly regulated by the functions of the SCF and APC/C ubiquitin ligases, and perturbation of their function can result in tumorigenesis. Although the SCF and APC/C complexes are well-established in growth control pathways, many aspects of their function remain unknown. Recent studies have shed light on the mechanism of SCF-mediated ubiquitination and new functions for the SCF complex and APC/C. Our expanding understanding of the roles of the SCF and APC/C complexes highlight the potential for targeted molecular therapies. PMID:19775879

  10. Control of cell growth: Rag GTPases in activation of TORC1.

    PubMed

    Yang, Huirong; Gong, Rui; Xu, Yanhui

    2013-08-01

    The target of rapamycin (TOR) is a central regulator controlling cell growth. TOR is highly conserved from yeast to mammals, and is deregulated in human cancers and diabetes. TOR complex 1 (TORC1) integrates signals from growth factors, cellular energy status, stress, and amino acids to control cell growth, mitochondrial metabolism, and lipid biosynthesis. The mechanisms of growth factors and cellular energy status in regulating TORC1 have been well established, whereas the mechanism by which amino acid induces TORC1 remains largely unknown. Recent studies revealed that Rag GTPases play a central role in the regulation of TORC1 activation in response to amino acids. In this review, we will discuss the recent progress in our understanding of Rag GTPase-regulated TORC1 activation in response to amino acids. Particular focus will be given to the function of Rag GTPases in TORC1 activation and how Rag GTPases are regulated by amino acids.

  11. Controlled neuronal cell patterning and guided neurite growth on micropatterned nanofiber platforms

    NASA Astrophysics Data System (ADS)

    Malkoc, Veysi; Gallego-Perez, Daniel; Nelson, Tyler; Lannutti, John J.; Hansford, Derek J.

    2015-12-01

    Patterning neuronal cells and guiding neurite growth are important for applications such as prosthetics, cell based biosensors, and tissue engineering. In this paper, a microdevice is presented that provides neuronal cell patterning and guided neurite growth on a collagen coated gelatin/PCL nanofiber mat. The pattern consisted of a grid of polystyrene microwells/nodes to confine the cell bodies and orthogonal grooves to guide neurite growth from each node. Vacuum assisted cell seeding was used to localize cell bodies in the microwells and physically separate the cells during seeding. The electrospun nanofiber mats under the polystyrene microstructures were coated with collagen to enhance the cellular attachment and enhance differentiation. We evaluated the performance of our device using adhesion, viability, and differentiation assays of neuron-like PC12 cells compared to controls for vacuum seeding, spatial isolation and guidance, and collagen coating of the fibers. The device provided PC12 cell patterning with increased adhesion, differentiation, and guided neurite outgrowth compared to controls, demonstrating its potential for in vitro neuronal cell patterning studies.

  12. Cyclic Stretch Affects Pulmonary Endothelial Cell Control of Pulmonary Smooth Muscle Cell Growth

    PubMed Central

    Ochoa, Cristhiaan D.; Baker, Haven; Hasak, Stephen; Matyal, Robina; Salam, Aleya; Hales, Charles A.; Hancock, William; Quinn, Deborah A.

    2008-01-01

    Endothelial cells are subjected to mechanical forces in the form of cyclic stretch resulting from blood pulsatility. Pulmonary artery endothelial cells (PAECs) produce factors that stimulate and inhibit pulmonary artery smooth muscle cell (PASMC) growth. We hypothesized that PAECs exposed to cyclic stretch secrete proteins that inhibit PASMC growth. Media from PAECs exposed to cyclic stretch significantly inhibited PASMC growth in a time-dependent manner. Lyophilized material isolated from stretched PAEC-conditioned media significantly inhibited PASMC growth in a dose-dependent manner. This inhibition was reversed by trypsin inactivation, which is consistent with the relevant factor being a protein(s). To identify proteins that inhibited cell growth in conditioned media from stretched PAECs, we used proteomic techniques and found that thrombospondin (TSP)-1, a natural antiangiogenic factor, was up-regulated by stretch. In vitro, exogenous TSP-1 inhibited PASMC growth. TSP-1–blocking antibodies reversed conditioned media–induced inhibition of PASMC growth. Cyclic stretched PAECs secrete protein(s) that inhibit PASMC proliferation. TSP-1 may be, at least in part, responsible for this inhibition. The complete identification and understanding of the secreted proteome of stretched PAECs may lead to new insights into the pathophysiology of pulmonary vascular remodeling. PMID:18314539

  13. Temperature control of growth and productivity in mutant Chinese hamster ovary cells synthesizing a recombinant protein.

    PubMed

    Jenkins, N; Hovey, A

    1993-11-05

    The use of a temperature switch to control the growth and productivity of temperature-sensitive (ts) mutants was investigated to extend the productive life span of recombinant Chinese hamster ovary (CHO) cells in batch culture. Bromodeoxyuridine was used at 39 degrees C to select mutagenized CHO-K1 cells, which resulted in the isolation of 31 temperature-sensitive mutants that were growth inhibited at 39 degrees C. Two of these mutants were successfully transfected with the gene for tissue inhibitor of metalloproteinases (TIMP) using glutamine synthetase amplification, and a permanent recombinant cell line established (5G1-B1) that maintains the ts phenotype.Continuous exposure to the nonpermissive temperature (npt) of 39 degrees C led to a rapid decline in cell viability. However, a temperature regime using alternating incubations at 34 degrees C and 39 degrees C arrested the 5G1-B1 cells while retaining a high cell viability for up to 170 h in culture. The specific production rate of the growth-arrested cells was 3-4 times that of control cultures maintained at a constant 34 degrees C over the crucial 72-130-h period of culture, which resulted in a 35% increase in the maximum product yield. Glucose uptake and lactate production both decreased in arrested cells. Flow cytometric analysis indicated that 5G1-B1 cells arrested in the G(1) or G(0) phase of the cell cycle, and no major structural damage was caused to these cells by the alternating temperature regime.These results demonstrate that growth-arrested ts CHO cells have increased productivity compared to growing cultures and maintain viability for longer periods. The system offers the prospect of enhancing the productivity of recombinant mammalian cells grown in simple batch fermentors.

  14. Rap1-GTP-interacting Adaptor Molecule (RIAM) Protein Controls Invasion and Growth of Melanoma Cells*

    PubMed Central

    Hernández-Varas, Pablo; Coló, Georgina P.; Bartolomé, Ruben A.; Paterson, Andrew; Medraño-Fernández, Iria; Arellano-Sánchez, Nohemí; Cabañas, Carlos; Sánchez-Mateos, Paloma; Lafuente, Esther M.; Boussiotis, Vassiliki A.; Strömblad, Staffan; Teixidó, Joaquin

    2011-01-01

    The Mig-10/RIAM/lamellipodin (MRL) family member Rap1-GTP-interacting adaptor molecule (RIAM) interacts with active Rap1, a small GTPase that is frequently activated in tumors such as melanoma and prostate cancer. We show here that RIAM is expressed in metastatic human melanoma cells and that both RIAM and Rap1 are required for BLM melanoma cell invasion. RIAM silencing in melanoma cells led to inhibition of tumor growth and to delayed metastasis in a severe combined immunodeficiency xenograft model. Defective invasion of RIAM-silenced melanoma cells arose from impairment in persistent cell migration directionality, which was associated with deficient activation of a Vav2-RhoA-ROCK-myosin light chain pathway. Expression of constitutively active Vav2 and RhoA in cells depleted for RIAM partially rescued their invasion, indicating that Vav2 and RhoA mediate RIAM function. These results suggest that inhibition of cell invasion in RIAM-silenced melanoma cells is likely based on altered cell contractility and cell polarization. Furthermore, we show that RIAM depletion reduces β1 integrin-dependent melanoma cell adhesion, which correlates with decreased activation of both Erk1/2 MAPK and phosphatidylinositol 3-kinase, two central molecules controlling cell growth and cell survival. In addition to causing inhibition of cell proliferation, RIAM silencing led to higher susceptibility to cell apoptosis. Together, these data suggest that defective activation of these kinases in RIAM-silenced cells could account for inhibition of melanoma cell growth and that RIAM might contribute to the dissemination of melanoma cells. PMID:21454517

  15. Polarity, cell division, and out-of-equilibrium dynamics control the growth of epithelial structures

    PubMed Central

    Cerruti, Benedetta; Puliafito, Alberto; Shewan, Annette M.; Yu, Wei; Combes, Alexander N.; Little, Melissa H.; Chianale, Federica; Primo, Luca; Serini, Guido; Mostov, Keith E.; Celani, Antonio

    2013-01-01

    The growth of a well-formed epithelial structure is governed by mechanical constraints, cellular apico-basal polarity, and spatially controlled cell division. Here we compared the predictions of a mathematical model of epithelial growth with the morphological analysis of 3D epithelial structures. In both in vitro cyst models and in developing epithelial structures in vivo, epithelial growth could take place close to or far from mechanical equilibrium, and was determined by the hierarchy of time-scales of cell division, cell–cell rearrangements, and lumen dynamics. Equilibrium properties could be inferred by the analysis of cell–cell contact topologies, and the nonequilibrium phenotype was altered by inhibiting ROCK activity. The occurrence of an aberrant multilumen phenotype was linked to fast nonequilibrium growth, even when geometric control of cell division was correctly enforced. We predicted and verified experimentally that slowing down cell division partially rescued a multilumen phenotype induced by altered polarity. These results improve our understanding of the development of epithelial organs and, ultimately, of carcinogenesis. PMID:24145168

  16. Control by fibroblast growth factor of differentiation in the BC3H1 muscle cell line

    PubMed Central

    1985-01-01

    The regulation of creatine phosphokinase (CPK) expression by polypeptide growth factors has been examined in the clonal mouse muscle BC3H1 cell line. After arrest of cell growth by exposure to low concentrations of serum, BC3H1 cells accumulate high levels of muscle- specific proteins including CPK. The induction of this enzyme is reversible in the presence of high concentrations of fetal calf serum, which cause quiescent, differentiated cells to reenter the cell cycle. Under these conditions, the rate of CPK synthesis is drastically reduced. We show in the present communication that either pituitary- derived fibroblast growth factor (FGF) or brain-derived FGF are as effective as serum in repressing the synthesis of CPK when added to quiescent, differentiated cells. The decrease in the rate of synthesis of CPK occurs within 22 h after the addition of pituitary FGF to the cells. Pituitary FGF had very little effect, if any, on the rate CPK degradation. The overall rate of protein synthesis and the pattern of synthesis of the major polypeptides made by these cells was not altered by the addition of FGF. Although pituitary FGF was mitogenic for BC3H1 cells, the rate of cell growth was not absolutely correlated with the extent of repression of CPK. Brain-derived FGF fully repressed CPK induction under conditions where it showed no significant mitogenic activity. These results show that the expression of a muscle-specific protein, CPK, can be controlled by a single defined polypeptide growth factor in fully differentiated cultures, and that initiation of cell division is not required for their regulation to take place. PMID:3988800

  17. Understanding CrRLK1L Function: Cell Walls and Growth Control.

    PubMed

    Nissen, Karen S; Willats, William G T; Malinovsky, Frederikke G

    2016-06-01

    To develop successfully in an ever-changing environment, it is essential for plants to monitor and control their growth. Therefore, cell expansion is carefully regulated to establish correct cell shape and size. In this review, we explore the role of the Catharanthus roseus receptor-like kinase (CrRLK1L) subfamily as regulators of cell expansion. Recently, the downstream signalling events of individual CrRLK1L pathways were discovered, implicating known modulators of cell expansion, such as reactive oxygen species (ROS) production, Ca(2+) dynamics, and exocytosis of cell wall material. Based on these intriguing new insights, we propose a model for a common pathway of CrRLK1L signalling that enables spatial and temporal control of cell wall extensibility throughout the plant.

  18. G1/S control of anchorage-independent growth in the fibroblast cell cycle

    PubMed Central

    1991-01-01

    We have developed methodology to identify the block to anchorage- independent growth and position it within the fibroblast cell cycle. Results with NRK fibroblasts show that mitogen stimulation of the G0/G1 transition and G1-associated increases in cell size are minimally affected by loss of cell anchorage. In contrast, the induction of G1/S cell cycle genes and DNA synthesis is markedly inhibited when anchorage is blocked. Moreover, we demonstrate that the anchorage-dependent transition maps to late G1 and shortly before activation of the G1/S p34cdc2-like kinase. The G1/S block was also detectable in NIH-3T3 cells. Our results: (a) distinguish control of cell cycle progression by growth factors and anchorage; (b) indicate that anchorage mediates G1/S control in fibroblasts; and (c) identify a physiologic circumstance in which the phenotype of mammalian cell cycle arrest would closely resemble Saccharomyces cerevisiae START. The close correlation between anchorage independence in vitro and tumorigenicity in vivo emphasizes the key regulatory role for G1/S control in mammalian cells. PMID:1955482

  19. Bacterial growth, detachment and cell size control on polyethylene terephthalate surfaces.

    PubMed

    Wang, Liyun; Fan, Daming; Chen, Wei; Terentjev, Eugene M

    2015-10-14

    In medicine and food industry, bacterial colonisation on surfaces is a common cause of infections and severe illnesses. However, the detailed quantitative information about the dynamics and the mechanisms involved in bacterial proliferation on solid substrates is still lacking. In this study we investigated the adhesion and detachment, the individual growth and colonisation, and the cell size control of Escherichia coli (E. coli) MG1655 on polyethylene terephthalate (PET) surfaces. The results show that the bacterial growth curve on PET exhibits the distinct lag and log phases, but the generation time is more than twice longer than in bulk medium. Single cells in the lag phase are more likely to detach than clustered ones in the log phase; clustered bacteria in micro-colonies have stronger adhesive bonds with surfaces and their neighbours with the progressing colonisation. We show that the cell size is under the density-dependent pathway control: when the adherent cells are at low density, the culture medium is responsible for coordinating cell division and cell size; when the clustered cells are at high population density, we demonstrate that the effect of quorum sensing causes the cell size decrease as the cell density on surfaces increases.

  20. Slug Controls Stem/Progenitor Cell Growth Dynamics during Mammary Gland Morphogenesis

    PubMed Central

    Selmi, Abdelkader; Côme, Christophe; Faraldo, Maria-Luisa M.; Deugnier, Marie-Ange; Savagner, Pierre

    2012-01-01

    Background Morphogenesis results from the coordination of distinct cell signaling pathways controlling migration, differentiation, apoptosis, and proliferation, along stem/progenitor cell dynamics. To decipher this puzzle, we focused on epithelial-mesenchymal transition (EMT) “master genes”. EMT has emerged as a unifying concept, involving cell-cell adhesion, migration and apoptotic pathways. EMT also appears to mingle with stemness. However, very little is known on the physiological role and relevance of EMT master-genes. We addressed this question during mammary morphogenesis. Recently, a link between Slug/Snai2 and stemness has been described in mammary epithelial cells, but EMT master genes actual localization, role and targets during mammary gland morphogenesis are not known and we focused on this basic question. Methodology/Principal Findings Using a Slug–lacZ transgenic model and immunolocalization, we located Slug in a distinct subpopulation covering about 10–20% basal cap and duct cells, mostly cycling cells, coexpressed with basal markers P-cadherin, CK5 and CD49f. During puberty, Slug-deficient mammary epithelium exhibited a delayed development after transplantation, contained less cycling cells, and overexpressed CK8/18, ER, GATA3 and BMI1 genes, linked to luminal lineage. Other EMT master genes were overexpressed, suggesting compensation mechanisms. Gain/loss-of-function in vitro experiments confirmed Slug control of mammary epithelial cell luminal differentiation and proliferation. In addition, they showed that Slug enhances specifically clonal mammosphere emergence and growth, cell motility, and represses apoptosis. Strikingly, Slug-deprived mammary epithelial cells lost their potential to generate secondary clonal mammospheres. Conclusions/Significance We conclude that Slug pathway controls the growth dynamics of a subpopulation of cycling progenitor basal cells during mammary morphogenesis. Overall, our data better define a key mechanism

  1. Epidermal growth factor controls smooth muscle alpha-isoactin expression in BC3H1 cells

    PubMed Central

    1988-01-01

    We have examined the effects of epidermal growth factor (EGF), platelet- derived growth factor, and insulin on the differentiation of a mouse vascular smooth muscle-like cell line, the BC3H1 cells. On the basis of cell morphology and smooth muscle alpha-isoactin synthesis, we demonstrate that EGF at physiological concentrations prevents the differentiation of these cells, whereas platelet-derived growth factor has no apparent effect. The induction of alpha-isoactin synthesis by serum deprivation is inhibited by EGF in a dose-dependent manner with a half-maximal effect at 3-5 ng/ml and a maximal inhibition at approximately 30 ng/ml. Northern analysis also shows that EGF blocks the accumulation of alpha-isoactin mRNA normally observed during cell differentiation. Addition of EGF to differentiated cells results in a repression of alpha-isoactin synthesis, a stimulation of beta- and gamma-isoactin synthesis, and the stabilization of the nonmuscle isoactins. The synthesis of creatine phosphokinase, a muscle-specific noncontractile protein, is also regulated by EGF in a similar fashion. Modulation by EGF of alpha-isoactin expression is not affected by aphidicolin and is therefore independent of its mitogenic effect on these cells. Insulin is not required for observation of the EGF- dependent effects but instead seems to promote differentiation. Our results show that EGF can replace serum in controlling the differentiation of BC3H1 cells. PMID:3279054

  2. TOR signaling regulates planarian stem cells and controls localized and organismal growth.

    PubMed

    Peiris, T Harshani; Weckerle, Frank; Ozamoto, Elyse; Ramirez, Daniel; Davidian, Devon; García-Ojeda, Marcos E; Oviedo, Néstor J

    2012-04-01

    Target of Rapamycin (TOR) controls an evolutionarily conserved signaling pathway that modulates cellular growth and division by sensing levels of nutrients, energy and stress. As such, TOR signaling is a crucial component of tissues and organs that translates systemic signals into cellular behavior. The ubiquitous nature of TOR signaling, together with the difficulty of analyzing tissue during cellular turnover and repair, have limited our understanding of how this kinase operates throughout the body. Here, we use the planarian model system to address TOR regulation at the organismal level. The planarian TOR homolog (Smed-TOR) is ubiquitously expressed, including stem cells (neoblasts) and differentiated tissues. Inhibition of TOR with RNA interference severely restricts cell proliferation, allowing the study of neoblasts with restricted proliferative capacity during regeneration and systemic cell turnover. Strikingly, TOR signaling is required for neoblast response to amputation and localized growth (blastema). However, in the absence of TOR signaling, regeneration takes place only within differentiated tissues. In addition, TOR is essential for maintaining the balance between cell division and cell death, and its dysfunction leads to tissue degeneration and lack of organismal growth in the presence of nutrients. Finally, TOR function is likely to be mediated through TOR Complex 1 as its disruption recapitulates signs of the TOR phenotype. Our data reveal novel roles for TOR signaling in controlling adult stem cells at a systemic level and suggest a new paradigm for studying TOR function during physiological turnover and regeneration.

  3. Shape-dependent control of cell growth, differentiation, and apoptosis: switching between attractors in cell regulatory networks

    NASA Technical Reports Server (NTRS)

    Huang, S.; Ingber, D. E.

    2000-01-01

    Development of characteristic tissue patterns requires that individual cells be switched locally between different phenotypes or "fates;" while one cell may proliferate, its neighbors may differentiate or die. Recent studies have revealed that local switching between these different gene programs is controlled through interplay between soluble growth factors, insoluble extracellular matrix molecules, and mechanical forces which produce cell shape distortion. Although the precise molecular basis remains unknown, shape-dependent control of cell growth and function appears to be mediated by tension-dependent changes in the actin cytoskeleton. However, the question remains: how can a generalized physical stimulus, such as cell distortion, activate the same set of genes and signaling proteins that are triggered by molecules which bind to specific cell surface receptors. In this article, we use computer simulations based on dynamic Boolean networks to show that the different cell fates that a particular cell can exhibit may represent a preprogrammed set of common end programs or "attractors" which self-organize within the cell's regulatory networks. In this type of dynamic network model of information processing, generalized stimuli (e.g., mechanical forces) and specific molecular cues elicit signals which follow different trajectories, but eventually converge onto one of a small set of common end programs (growth, quiescence, differentiation, apoptosis, etc.). In other words, if cells use this type of information processing system, then control of cell function would involve selection of preexisting (latent) behavioral modes of the cell, rather than instruction by specific binding molecules. Importantly, the results of the computer simulation closely mimic experimental data obtained with living endothelial cells. The major implication of this finding is that current methods used for analysis of cell function that rely on characterization of linear signaling pathways or

  4. Shape-dependent control of cell growth, differentiation, and apoptosis: switching between attractors in cell regulatory networks

    NASA Technical Reports Server (NTRS)

    Huang, S.; Ingber, D. E.

    2000-01-01

    Development of characteristic tissue patterns requires that individual cells be switched locally between different phenotypes or "fates;" while one cell may proliferate, its neighbors may differentiate or die. Recent studies have revealed that local switching between these different gene programs is controlled through interplay between soluble growth factors, insoluble extracellular matrix molecules, and mechanical forces which produce cell shape distortion. Although the precise molecular basis remains unknown, shape-dependent control of cell growth and function appears to be mediated by tension-dependent changes in the actin cytoskeleton. However, the question remains: how can a generalized physical stimulus, such as cell distortion, activate the same set of genes and signaling proteins that are triggered by molecules which bind to specific cell surface receptors. In this article, we use computer simulations based on dynamic Boolean networks to show that the different cell fates that a particular cell can exhibit may represent a preprogrammed set of common end programs or "attractors" which self-organize within the cell's regulatory networks. In this type of dynamic network model of information processing, generalized stimuli (e.g., mechanical forces) and specific molecular cues elicit signals which follow different trajectories, but eventually converge onto one of a small set of common end programs (growth, quiescence, differentiation, apoptosis, etc.). In other words, if cells use this type of information processing system, then control of cell function would involve selection of preexisting (latent) behavioral modes of the cell, rather than instruction by specific binding molecules. Importantly, the results of the computer simulation closely mimic experimental data obtained with living endothelial cells. The major implication of this finding is that current methods used for analysis of cell function that rely on characterization of linear signaling pathways or

  5. Poly(ADP-Ribose)Polymerase Activity Controls Plant Growth by Promoting Leaf Cell Number

    PubMed Central

    Schulz, Philipp; Jansseune, Karel; Degenkolbe, Thomas; Méret, Michaël; Claeys, Hannes; Skirycz, Aleksandra; Teige, Markus; Willmitzer, Lothar; Hannah, Matthew A.

    2014-01-01

    A changing global environment, rising population and increasing demand for biofuels are challenging agriculture and creating a need for technologies to increase biomass production. Here we demonstrate that the inhibition of poly (ADP-ribose) polymerase activity is a promising technology to achieve this under non-stress conditions. Furthermore, we investigate the basis of this growth enhancement via leaf series and kinematic cell analysis as well as single leaf transcriptomics and plant metabolomics under non-stress conditions. These data indicate a regulatory function of PARP within cell growth and potentially development. PARP inhibition enhances growth of Arabidopsis thaliana by enhancing the cell number. Time course single leaf transcriptomics shows that PARP inhibition regulates a small subset of genes which are related to growth promotion, cell cycle and the control of metabolism. This is supported by metabolite analysis showing overall changes in primary and particularly secondary metabolism. Taken together the results indicate a versatile function of PARP beyond its previously reported roles in controlling plant stress tolerance and thus can be a useful target for enhancing biomass production. PMID:24587323

  6. Poly(ADP-ribose)polymerase activity controls plant growth by promoting leaf cell number.

    PubMed

    Schulz, Philipp; Jansseune, Karel; Degenkolbe, Thomas; Méret, Michaël; Claeys, Hannes; Skirycz, Aleksandra; Teige, Markus; Willmitzer, Lothar; Hannah, Matthew A

    2014-01-01

    A changing global environment, rising population and increasing demand for biofuels are challenging agriculture and creating a need for technologies to increase biomass production. Here we demonstrate that the inhibition of poly (ADP-ribose) polymerase activity is a promising technology to achieve this under non-stress conditions. Furthermore, we investigate the basis of this growth enhancement via leaf series and kinematic cell analysis as well as single leaf transcriptomics and plant metabolomics under non-stress conditions. These data indicate a regulatory function of PARP within cell growth and potentially development. PARP inhibition enhances growth of Arabidopsis thaliana by enhancing the cell number. Time course single leaf transcriptomics shows that PARP inhibition regulates a small subset of genes which are related to growth promotion, cell cycle and the control of metabolism. This is supported by metabolite analysis showing overall changes in primary and particularly secondary metabolism. Taken together the results indicate a versatile function of PARP beyond its previously reported roles in controlling plant stress tolerance and thus can be a useful target for enhancing biomass production.

  7. Synthesis of labile, serum-dependent protein in early G1 controls animal cell growth

    PubMed Central

    Rossow, Peter W.; Riddle, Veronica G. H.; Pardee, Arthur B.

    1979-01-01

    We present a model to account for several major observations on growth control of animal cells in culture. This model is tested by means of kinetic experiments which show that exponentially growing animal cells whose ability to synthesize total protein has been inhibited with cycloheximide (by up to 70%) grow at rates approximately proportional to their rates of protein synthesis. However, virtually the entire elongation of the cell cycle occurs in the part of the G1 phase that depends on a high concentration of serum in the medium. This part of the cycle has earlier been suggested to lie prior to the restriction point—i.e., the point beyond the main regulatory processes of G1. The remainder of the cycle, from restriction point to mitosis, is markedly insensitive to these concentrations of cycloheximide as well as to growth regulation. We quantitatively account for the specific lengthening of that part of the cycle involved in growth regulation by assuming that cells must accumulate a specific protein in a critical amount before they can proceed beyond the restriction point. The lability of this protein (half-life about 2 hr) makes its accumulation unusually sensitive to inhibition of total protein synthesis by cycloheximide. Its production appears to depend on growth factors provided by serum. The model can also account for greater variations of G1 durations as the growth of cell populations is made slower. It also predicts two sorts of quiescence: one of cells slowly traversing G1, in slightly suboptimal conditions; the other of cells that enter G0 under inadequate conditions. Transformation of different sorts could create cells with altered variables for initiation, synthesis, or inactivation of the regulatory protein or could altogether eliminate the need for the protein. PMID:291975

  8. Solvent engineering towards controlled grain growth in perovskite planar heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Rong, Yaoguang; Tang, Zhongjia; Zhao, Yufeng; Zhong, Xin; Venkatesan, Swaminathan; Graham, Harrison; Patton, Matthew; Jing, Yan; Guloy, Arnold M.; Yao, Yan

    2015-06-01

    We report an effective solvent engineering process to enable controlled perovskite crystal growth and a wider window for processing uniform and dense methyl ammonium lead iodide (MAPbI3) perovskite films. Planar heterojunction solar cells fabricated with this method demonstrate hysteresis-free performance with a power conversion efficiency around 10%. The crystal structure of an organic-based Pb iodide intermediate phase is identified for the first time, which is critical in controlling the crystal growth and optimizing thin film morphology.We report an effective solvent engineering process to enable controlled perovskite crystal growth and a wider window for processing uniform and dense methyl ammonium lead iodide (MAPbI3) perovskite films. Planar heterojunction solar cells fabricated with this method demonstrate hysteresis-free performance with a power conversion efficiency around 10%. The crystal structure of an organic-based Pb iodide intermediate phase is identified for the first time, which is critical in controlling the crystal growth and optimizing thin film morphology. Electronic supplementary information (ESI) available: Detailed Experimental methods; photovoltaic performance of the devices; An X-ray crystallographic file (CIF). See DOI: 10.1039/c5nr02866c

  9. Nitrogen dioxide regulates organ growth by controlling cell proliferation and enlargement in Arabidopsis.

    PubMed

    Takahashi, Misa; Furuhashi, Takamasa; Ishikawa, Naoko; Horiguchi, Gorou; Sakamoto, Atsushi; Tsukaya, Hirokazu; Morikawa, Hiromichi

    2014-03-01

    • To gain more insight into the physiological function of nitrogen dioxide (NO₂), we investigated the effects of exogenous NO₂ on growth in Arabidopsis thaliana. • Plants were grown in air without NO₂ for 1 wk after sowing and then grown for 1-4 wk in air with (designated treated plants) or without (control plants) NO₂. Plants were irrigated semiweekly with a nutrient solution containing 19.7 mM nitrate and 10.3 mM ammonium. • Five-week-old plants treated with 50 ppb NO₂ showed a ≤ 2.8-fold increase in biomass relative to controls. Treated plants also showed early flowering. The magnitude of the effects of NO₂ on leaf expansion, cell proliferation and enlargement was greater in developing than in maturing leaves. Leaf areas were 1.3-8.4 times larger on treated plants than corresponding leaves on control plants. The NO₂-induced increase in leaf size was largely attributable to cell proliferation in developing leaves, but was attributable to both cell proliferation and enlargement in maturing leaves. The expression of different sets of genes for cell proliferation and/or enlargement was induced by NO₂, but depended on the leaf developmental stage. • Collectively, these results indicated that NO₂ regulates organ growth by controlling cell proliferation and enlargement. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  10. Strategies for Controlled Delivery of Growth Factors and Cells for Bone Regeneration

    PubMed Central

    Vo, Tiffany N.; Kasper, F. Kurtis; Mikos, Antonios G.

    2012-01-01

    The controlled delivery of growth factors and cells within biomaterial carriers can enhance and accelerate functional bone formation. The carrier system can be designed with preprogrammed release kinetics to deliver bioactive molecules in a localized, spatiotemporal manner most similar to the natural wound healing process. The carrier can also act as an extracellular matrix-mimicking substrate for promoting osteoprogenitor cellular infiltration and proliferation for integrative tissue repair. This review discusses the role of various regenerative factors involved in bone healing and their appropriate combinations with different delivery systems for augmenting bone regeneration. The general requirements of protein, cell and gene therapy are described, with elaboration on how the selection of materials, configurations and processing affects growth factor and cell delivery and regenerative efficacy in both in vitro and in vivo applications for bone tissue engineering. PMID:22342771

  11. Neuroendocrine control of T cell development in mammals: role of growth hormone in modulating thymocyte migration.

    PubMed

    Savino, Wilson

    2007-09-01

    The thymus gland is a primary lymphoid organ, in which bone-marrow-derived T cell precursors undergo differentiation, eventually leading to migration of positively selected cells to the peripheral lymphoid organs. This differentiation occurs along with cell migration in the context of the thymic microenvironment, a three-dimensional network formed by epithelial cells, macrophages, dendritic cells, fibroblasts and extracellular matrix components. A series of data clearly shows that growth hormone (GH) pleiotropically modulates thymic functions. For example, GH upregulates proliferation of thymocytes and thymic epithelial cells. Accordingly, GH-transgenic mice, as well as animals and humans treated with exogenous GH, exhibit an enhanced cellularity in the organ. Growth hormone stimulates the secretion of thymic hormones, cytokines and chemokines by the thymic microenvironment, as well as the production of extracellular matrix proteins, leading to an increase in thymocyte migratory responses and intrathymic traffic of developing T cells. In addition, GH stimulates the in vivo export of thymocytes from the organ, as ascertained by studies with intrathymic injection of GH in normal mice and with GH-transgenic mice. Moreover, since GH is produced by thymocytes and thymic epithelial cells, which express GH receptors, we should consider that, in addition to the classic endocrine pathway, the GH control of the thymus may include an autocrine/paracrine pathway. Finally, since GH promotes a replenishment of the thymus and an increase of thymocyte export, it could be envisioned as a potential adjuvant therapeutic agent in the treatment of immunodeficiencies associated with thymic atrophy.

  12. The Effect of Controlled Growth Factor Delivery on Embryonic Stem Cell Differentiation Inside of Fibrin Scaffolds

    PubMed Central

    Willerth, Stephanie M.; Rader, Allison; Sakiyama-Elbert, Shelly E.

    2009-01-01

    The goal of this project is to develop 3-D biomaterial scaffolds that present cues to direct differentiation of embryonic stem cell derived neural progenitor cells (ESNPCs) seeded inside into mature neural phenotypes, specifically neurons and oligodendrocytes. Release studies were performed to determine the appropriate conditions for retention of neurotrophin-3 (NT-3), sonic hedgehog (Shh), and platelet derived growth factor (PDGF) by an affinity-based delivery system (ABDS) incorporated into fibrin scaffolds. Embryoid bodies (EBs) containing neural progenitors were formed from mouse ES cells, using a 4−/4+ retinoic acid treatment protocol, and then seeded inside of fibrin scaffolds containing the drug delivery system. This delivery system was used to deliver various growth factor doses and combinations to the cells seeded inside of the scaffolds. Controlled delivery of NT-3 and PDGF simultaneously increased the fraction of neural progenitors, neurons, and oligodendrocytes while decreasing the fraction of astrocytes obtained compared to control cultures seeded inside of unmodified fibrin scaffolds with no growth factors present in the media. These results demonstrate that such a strategy can be used to generate an engineered tissue for the potential treatment of spinal cord injury and could be extended to study of differentiation in other tissues. PMID:19383401

  13. Control over Silica Particle Growth and Particle–Biomolecule Interactions Facilitates Silica Encapsulation of Mammalian Cells with Thickness Control

    DOE PAGES

    Johnston, Robert K.; Harper, Jason C.; Tartis, Michaelann S.

    2017-07-13

    Over the past 20 years, many strategies utilizing sol–gel chemistry to integrate biological cells into silica-based materials have been reported. One such strategy, Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition, shows promise as an efficient encapsulation technique due to the ability to vary the silica encapsulation morphology obtained by this process through variation of SG-CViL reaction conditions. In this report, we develop SG-CViL as a tunable, multi-purpose silica encapsulation strategy by investigating the mechanisms governing both silica particle generation and subsequent interaction with phospholipid assemblies (liposomes and living cells). Using Dynamic Light Scattering (DLS) measurements, linear and exponential silica particlemore » growth dynamics were observed which were dependent on deposition buffer ion constituents and ion concentration. Silica particle growth followed a cluster–cluster growth mechanism at acidic pH, and a monomer-cluster growth mechanism at neutral to basic pH. Increasing silica sol aging temperature resulted in higher rates of particle growth and larger particles. DLS measurements employing PEG-coated liposomes and cationic liposomes, serving as model phospholipid assemblies, revealed that electrostatic interactions promote more stable liposome–silica interactions than hydrogen bonding and facilitate silica coating on suspension cells. However, continued silica reactivity leads to aggregation of silica-coated suspension cells, revealing the need for cell isolation to tune deposited silica thickness. As a result, utilizing these mechanistic study insights, silica was deposited onto adherent HeLa cells under biocompatible conditions with micrometer-scale control over silica thickness, minimal cell manipulation steps, and retained cell viability over several days.« less

  14. Control of intracellular pH and growth by fibronectin in capillary endothelial cells

    NASA Technical Reports Server (NTRS)

    Ingber, D. E.; Prusty, D.; Frangioni, J. V.; Cragoe, E. J. Jr; Lechene, C.; Schwartz, M. A.

    1990-01-01

    The aim of this work was to analyze the mechanism by which fibronectin (FN) regulates capillary endothelial cell proliferation. Endothelial cell growth can be controlled in chemically-defined medium by varying the density of FN coated on the substratum (Ingber, D. E., and J. Folkman. J. Cell Biol. 1989. 109:317-330). In this system, DNA synthetic rates are stimulated by FN in direct proportion to its effect on cell extension (projected cell areas) both in the presence and absence of saturating amounts of basic FGF. To investigate direct growth signaling by FN, we carried out microfluorometric measurements of intracellular pH (pHi), a cytoplasmic signal that is commonly influenced by soluble mitogens. pHi increased 0.18 pH units as FN coating densities were raised and cells progressed from round to spread. Intracellular alkalinization induced by attachment to FN was rapid and followed the time course of cell spreading. When measured in the presence and absence of FGF, the effects of FN and FGF on pHi were found to be independent and additive. Furthermore, DNA synthesis correlated with pHi for all combinations of FGF and FN. Ethylisopropylamiloride, a specific inhibitor of the plasma membrane Na+/H+ antiporter, completely suppressed the effects of FN on both pHi and DNA synthesis. However, cytoplasmic pH per se did not appear to be a critical determinant of growth since DNA synthesis was not significantly inhibited when pHi was lowered over the physiological range by varying the pH of the medium. We conclude that FN and FGF exert their growth-modulating effects in part through activation of the Na+/H+ exchanger, although they appear to trigger this system via separate pathways.

  15. Control of intracellular pH and growth by fibronectin in capillary endothelial cells

    PubMed Central

    1990-01-01

    The aim of this work was to analyze the mechanism by which fibronectin (FN) regulates capillary endothelial cell proliferation. Endothelial cell growth can be controlled in chemically-defined medium by varying the density of FN coated on the substratum (Ingber, D. E., and J. Folkman. J. Cell Biol. 1989. 109:317-330). In this system, DNA synthetic rates are stimulated by FN in direct proportion to its effect on cell extension (projected cell areas) both in the presence and absence of saturating amounts of basic FGF. To investigate direct growth signaling by FN, we carried out microfluorometric measurements of intracellular pH (pHi), a cytoplasmic signal that is commonly influenced by soluble mitogens. pHi increased 0.18 pH units as FN coating densities were raised and cells progressed from round to spread. Intracellular alkalinization induced by attachment to FN was rapid and followed the time course of cell spreading. When measured in the presence and absence of FGF, the effects of FN and FGF on pHi were found to be independent and additive. Furthermore, DNA synthesis correlated with pHi for all combinations of FGF and FN. Ethylisopropylamiloride, a specific inhibitor of the plasma membrane Na+/H+ antiporter, completely suppressed the effects of FN on both pHi and DNA synthesis. However, cytoplasmic pH per se did not appear to be a critical determinant of growth since DNA synthesis was not significantly inhibited when pHi was lowered over the physiological range by varying the pH of the medium. We conclude that FN and FGF exert their growth-modulating effects in part through activation of the Na+/H+ exchanger, although they appear to trigger this system via separate pathways. PMID:2159481

  16. Control of intracellular pH and growth by fibronectin in capillary endothelial cells

    NASA Technical Reports Server (NTRS)

    Ingber, D. E.; Prusty, D.; Frangioni, J. V.; Cragoe, E. J. Jr; Lechene, C.; Schwartz, M. A.

    1990-01-01

    The aim of this work was to analyze the mechanism by which fibronectin (FN) regulates capillary endothelial cell proliferation. Endothelial cell growth can be controlled in chemically-defined medium by varying the density of FN coated on the substratum (Ingber, D. E., and J. Folkman. J. Cell Biol. 1989. 109:317-330). In this system, DNA synthetic rates are stimulated by FN in direct proportion to its effect on cell extension (projected cell areas) both in the presence and absence of saturating amounts of basic FGF. To investigate direct growth signaling by FN, we carried out microfluorometric measurements of intracellular pH (pHi), a cytoplasmic signal that is commonly influenced by soluble mitogens. pHi increased 0.18 pH units as FN coating densities were raised and cells progressed from round to spread. Intracellular alkalinization induced by attachment to FN was rapid and followed the time course of cell spreading. When measured in the presence and absence of FGF, the effects of FN and FGF on pHi were found to be independent and additive. Furthermore, DNA synthesis correlated with pHi for all combinations of FGF and FN. Ethylisopropylamiloride, a specific inhibitor of the plasma membrane Na+/H+ antiporter, completely suppressed the effects of FN on both pHi and DNA synthesis. However, cytoplasmic pH per se did not appear to be a critical determinant of growth since DNA synthesis was not significantly inhibited when pHi was lowered over the physiological range by varying the pH of the medium. We conclude that FN and FGF exert their growth-modulating effects in part through activation of the Na+/H+ exchanger, although they appear to trigger this system via separate pathways.

  17. mTOR Controls Ovarian Follicle Growth by Regulating Granulosa Cell Proliferation

    PubMed Central

    Yu, James; Yaba, Aylin; Kasiman, Corinna; Thomson, Travis; Johnson, Joshua

    2011-01-01

    We have shown that inhibition of mTOR in granulosa cells and ovarian follicles results in compromised granulosa proliferation and reduced follicle growth. Further analysis here using spontaneously immortalized rat granulosa cells has revealed that mTOR pathway activity is enhanced during M-phase of the cell cycle. mTOR specific phosphorylation of p70S6 kinase and 4E-BP, and expression of Raptor are all enhanced during M-phase. The predominant effect of mTOR inhibition by the specific inhibitor Rapamycin (RAP) was a dose-responsive arrest in the G1 cell cycle stage. The fraction of granulosa cells that continued to divide in the presence of RAP exhibited a dose-dependent increase in aberrant mitotic figures known as anaphase bridges. Strikingly, estradiol consistently decreased the incidence of aberrant mitotic figures. In mice treated with RAP, the mitotic index was reduced compared to controls, and a similar increase in aberrant mitotic events was noted. RAP injected during a superovulation regime resulted in a dose-dependent reduction in the numbers of eggs ovulated. Implications for the real-time regulation of follicle growth and dominance, including the consequences of increased numbers of aneuploid granulosa cells, are discussed. PMID:21750711

  18. Fis1 deficiency selects for compensatory mutations responsible for cell death and growth control defects.

    PubMed

    Cheng, W-C; Teng, X; Park, H K; Tucker, C M; Dunham, M J; Hardwick, J M

    2008-12-01

    Genetic mutations affecting mitochondrial fission and fusion proteins cause human neurological disorders, but are assumed to be well tolerated in yeast. The conserved mitochondrial fission protein Dnm1/Drp1 is required for normal mitochondrial division, but also promotes cell death in mammals and yeast. Fis1, an outer mitochondrial membrane-anchored receptor for Dnm1/Drp1, also can promote cell death in mammals, but appears to have prosurvival activity in yeast. Here we report that deletion of the FIS1 gene in yeast consistently results in acquisition of a secondary mutation that confers sensitivity to cell death. In several independently derived FIS1 knockouts, tiling arrays and genomic sequencing identified the secondary mutation as a premature termination in the same stress-response gene, WHI2. The WHI2 mutation rescues the mitochondrial respiratory defect (petite formation) caused by FIS1 deficiency, but also causes a failure to suppress cell growth during amino-acid deprivation. Thus, loss of Fis1 drives the selection for specific compensatory mutations that confer defective growth control and cell death regulation, characteristic of human tumor cells. The important long-term survival function of Fis1 that is compensated by WHI2 mutation appears to be independent of fission factor Dnm1/Drp1 and its adaptor Mdv1, but may be mediated through a second adaptor Caf4, as WHI2 is also mutated in a CAF4 knockout.

  19. Fis1 deficiency selects for compensatory mutations responsible for cell death and growth control defects

    PubMed Central

    Cheng, W-C; Teng, X; Park, HK; Tucker, CM; Dunham, MJ; Hardwick, JM

    2008-01-01

    Genetic mutations affecting mitochondrial fission and fusion proteins cause human neurological disorders, but are assumed to be well tolerated in yeast. The conserved mitochondrial fission protein Dnm1/Drp1 is required for normal mitochondrial division, but also promotes cell death in mammals and yeast. Fis1, an outer mitochondrial membrane-anchored receptor for Dnm1/Drp1, also can promote cell death in mammals, but appears to have prosurvival activity in yeast. Here we report that deletion of the FIS1 gene in yeast consistently results in acquisition of a secondary mutation that confers sensitivity to cell death. In several independently derived FIS1 knockouts, tiling arrays and genomic sequencing identified the secondary mutation as a premature termination in the same stress-response gene, WHI2. The WHI2 mutation rescues the mitochondrial respiratory defect (petite formation) caused by FIS1 deficiency, but also causes a failure to suppress cell growth during amino-acid deprivation. Thus, loss of Fis1 drives the selection for specific compensatory mutations that confer defective growth control and cell death regulation, characteristic of human tumor cells. The important long-term survival function of Fis1 that is compensated by WHI2 mutation appears to be independent of fission factor Dnm1/Drp1 and its adaptor Mdv1, but may be mediated through a second adaptor Caf4, as WHI2 is also mutated in a CAF4 knockout. PMID:18756280

  20. Rethinking cell growth models.

    PubMed

    Kafri, Moshe; Metzl-Raz, Eyal; Jonas, Felix; Barkai, Naama

    2016-11-01

    The minimal description of a growing cell consists of self-replicating ribosomes translating the cellular proteome. While neglecting all other cellular components, this model provides key insights into the control and limitations of growth rate. It shows, for example, that growth rate is maximized when ribosomes work at full capacity, explains the linear relation between growth rate and the ribosome fraction of the proteome and defines the maximal possible growth rate. This ribosome-centered model also highlights the challenge of coordinating cell growth with related processes such as cell division or nutrient production. Coordination is promoted when ribosomes don't translate at maximal capacity, as it allows escaping strict exponential growth. Recent data support the notion that multiple cellular processes limit growth. In particular, increasing transcriptional demand may be as deleterious as increasing translational demand, depending on growth conditions. Consistent with the idea of trade-off, cells may forgo maximal growth to enable more efficient interprocess coordination and faster adaptation to changing conditions. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Polo kinase links the stress pathway to cell cycle control and tip growth in fission yeast.

    PubMed

    Petersen, Janni; Hagan, Iain M

    2005-05-26

    Stress-activated mitogen-activated protein kinase cascades instigate a range of changes to enable eukaryotic cells to cope with particular insults. In Schizosaccharomyces pombe these responses include the transcription of specific gene sets and inhibition of entry into mitosis. The S. pombe stress response pathway (SRP) also promotes commitment to mitosis in unperturbed cell cycles to allow cells to match their rate of division with nutrient availability. The nature of this SRP function in cell cycle control is unknown. Entry into mitosis is controlled by mitosis-promoting factor (MPF; Cdc2/cyclin B) activity. Inhibitory phosphorylation of Cdc2 by Wee1 kinase inactivates MPF until Cdc25 removes this phosphate to promote mitosis. The balance between Wee1 and Cdc25 activities is influenced by the recruitment of polo kinase (Plo1) to the spindle pole body (SPB). The SPB component Cut12 mediates this recruitment. Hyper-activating mutations in either cut12 or plo1 enable Cdc25-defective cells to enter mitosis. The hyperactive cut12.s11 mutation suppresses cdc25.22, as it promotes recruitment of active Plo1 to interphase SPBs. Here we show that the SRP promotes phosphorylation of Plo1 on Ser 402. In unperturbed cell cycles, SRP-mediated phosphorylation of Ser 402 promotes Plo1 recruitment to SPBs and thus commitment to mitosis. Ser 402 phosphorylation also ensures efficient reinitiation of cell tip growth and cell division during recovery from particular stresses. Thus, phosphorylation of Plo1 Ser 402 not only enables SRP signalling to modulate the timing of mitotic commitment in response to nutrient status in unperturbed cycles, but also promotes the return to normal cell cycle control after stress.

  2. Pseudopod growth and evolution during cell movement is controlled through SCAR/WAVE dephosphorylation

    PubMed Central

    Ura, Seiji; Pollitt, Alice Y.; Veltman, Douwe M.; Morrice, Nicholas A.; Machesky, Laura M.; Insall, Robert H.

    2016-01-01

    Background SCAR/WAVE is a principal regulator of pseudopod growth in crawling cells. It exists in a stable pentameric complex, which is regulated at multiple levels that are only beginning to be understood. SCAR/WAVE is phosphorylated at multiple sites, but how this affects its biological activity is unclear. Here we show that dephosphorylation of Dictyostelium SCAR controls normal pseudopod dynamics. Results We demonstrate that the C-terminal acidic domain of most Dictyostelium SCAR is basally phosphorylated at four serine residues. A small amount of singly phosphorylated SCAR is also found. SCAR phosphorylation site mutants cannot replace SCAR’s role in the pseudopod cycle, though they rescue cell size and growth. Unphosphorylatable SCAR is hyperactive – excessive recruitment to the front gives large pseudopods that fail to bifurcate because they continually grow forwards. Conversely, phosphomimetic SCAR is weakly active, causing frequent small, disorganised pseudopods. Even in its regulatory complex, SCAR is normally held inactive by an interaction between the phosphorylated acidic and basic domains. Loss of basic residues complementary to the acidic phosphosites yields a hyperactive protein similar to unphosphorylatable SCAR. Conclusions Regulated dephosphorylation of a fraction of the cellular SCAR pool is a key step in SCAR activation during pseudopod growth. Phosphorylation increases autoinhibition of the intact complex. Dephosphorylation weakens this interaction and facilitates SCAR activation, but also destabilizes the protein. We show that SCAR is specifically dephosphorylated in pseudopods, increasing activation by Rac and lipids and supporting positive feedback of pseudopod growth. PMID:22386315

  3. Topological Control of Extracellular Matrix Growth: A Native-Like Model for Cell Morphodynamics Studies.

    PubMed

    Caballero, David; Samitier, Josep

    2017-02-01

    The interaction of cells with their natural environment influences a large variety of cellular phenomena, including cell adhesion, proliferation, and migration. The complex extracellular matrix network has challenged the attempts to replicate in vitro the heterogeneity of the cell environment and has threatened, in general, the relevance of in vitro studies. In this work, we describe a new and extremely versatile approach to generate native-like extracellular matrices with controlled morphologies for the in vitro study of cellular processes. This general approach combines the confluent culture of fibroblasts with microfabricated guiding templates to direct the three-dimensional growth of well-defined extracellular networks which recapitulate the structural and biomolecular complexity of features typically found in vivo. To evaluate its performance, we studied fundamental cellular processes, including cell cytoskeleton organization, cell-matrix adhesion, proliferation, and protrusions morphodynamics. In all cases, we found striking differences depending on matrix architecture and, in particular, when compared to standard two-dimensional environments. We also assessed whether the engineered matrix networks influenced cell migration dynamics and locomotion strategy, finding enhanced migration efficiency for cells seeded on aligned matrices. Altogether, our methodology paves the way to the development of high-performance models of the extracellular matrix for potential applications in tissue engineering, diagnosis, or stem-cell biology.

  4. The REVEILLE Clock Genes Inhibit Growth of Juvenile and Adult Plants by Control of Cell Size.

    PubMed

    Gray, Jennifer A; Shalit-Kaneh, Akiva; Chu, Dalena Nhu; Hsu, Polly Yingshan; Harmer, Stacey L

    2017-04-01

    The circadian clock is a complex regulatory network that enhances plant growth and fitness in a constantly changing environment. In Arabidopsis (Arabidopsis thaliana), the clock is composed of numerous regulatory feedback loops in which REVEILLE8 (RVE8) and its homologs RVE4 and RVE6 act in a partially redundant manner to promote clock pace. Here, we report that the remaining members of the RVE8 clade, RVE3 and RVE5, play only minor roles in the regulation of clock function. However, we find that RVE8 clade proteins have unexpected functions in the modulation of light input to the clock and the control of plant growth at multiple stages of development. In seedlings, these proteins repress hypocotyl elongation in a daylength- and sucrose-dependent manner. Strikingly, adult rve4 6 8 and rve3 4 5 6 8 mutants are much larger than wild-type plants, with both increased leaf area and biomass. This size phenotype is associated with a faster growth rate and larger cell size and is not simply due to a delay in the transition to flowering. Gene expression and epistasis analysis reveal that the growth phenotypes of rve mutants are due to the misregulation of PHYTOCHROME INTERACTING FACTOR4 (PIF4) and PIF5 expression. Our results show that even small changes in PIF gene expression caused by the perturbation of clock gene function can have large effects on the growth of adult plants. © 2017 American Society of Plant Biologists. All Rights Reserved.

  5. Balanced cell proliferation and expansion is essential for flowering stem growth control.

    PubMed

    Ferjani, Ali; Hanai, Kenya; Gunji, Shizuka; Maeda, Saori; Sawa, Shinichiro; Tsukaya, Hirokazu

    2015-01-01

    The postembryonic development of aboveground plant organs relies on a continuous supply of cells from the shoot apical meristem. Previous studies of developmental regulation in leaves and flowers have revealed the crucial role of coordinated cell proliferation and differentiation during organogenesis. However, the importance of this coordination has not been examined in flowering stems. Very recently, we attempted to identify regulatory factors that maintain flowering stem integrity. We found that the increased cell number in clavata (clv) mutants and the decreased cell size in de-etiolated (det)3-1 resulted in flowering stems that were thicker and thinner, respectively, than in wild-type (WT) plants. Interestingly, in the cell proliferation- and cell expansion-defective double mutant clv det3-1, the flowering stems often exhibited severe cracking, resulting in exposure of their inner tissues. In this study, further quantification of the cellular phenotypes in the cotyledons and leaves revealed no differences between det3-1 and clv3 det3-1. Together, the above findings suggest that the clv3 mutation in a det3-1 background primarily affects flowering stems, while its effect on other organs is likely negligible. We propose that the coordination between cell proliferation and differentiation is not only important during leaf development, but also plays a role in the growth control of Arabidopsis flowering stems.

  6. Balanced cell proliferation and expansion is essential for flowering stem growth control

    PubMed Central

    Ferjani, Ali; Hanai, Kenya; Gunji, Shizuka; Maeda, Saori; Sawa, Shinichiro; Tsukaya, Hirokazu

    2015-01-01

    The postembryonic development of aboveground plant organs relies on a continuous supply of cells from the shoot apical meristem. Previous studies of developmental regulation in leaves and flowers have revealed the crucial role of coordinated cell proliferation and differentiation during organogenesis. However, the importance of this coordination has not been examined in flowering stems. Very recently, we attempted to identify regulatory factors that maintain flowering stem integrity. We found that the increased cell number in clavata (clv) mutants and the decreased cell size in de-etiolated (det)3-1 resulted in flowering stems that were thicker and thinner, respectively, than in wild-type (WT) plants. Interestingly, in the cell proliferation- and cell expansion-defective double mutant clv det3-1, the flowering stems often exhibited severe cracking, resulting in exposure of their inner tissues. In this study, further quantification of the cellular phenotypes in the cotyledons and leaves revealed no differences between det3-1 and clv3 det3-1. Together, the above findings suggest that the clv3 mutation in a det3-1 background primarily affects flowering stems, while its effect on other organs is likely negligible. We propose that the coordination between cell proliferation and differentiation is not only important during leaf development, but also plays a role in the growth control of Arabidopsis flowering stems. PMID:25831425

  7. Expression of transforming growth factor-beta (TGF-beta) receptors, TGF-beta 1 and TGF-beta 2 production and autocrine growth control in osteosarcoma cells.

    PubMed

    Kloen, P; Jennings, C L; Gebhardt, M C; Springfield, D S; Mankin, H J

    1994-08-01

    Transforming growth factor-beta (TGF-beta) is a polypeptide with multiple physiological functions. Isoforms of this growth factor have important roles in control of the cell cycle, in regulation of cell-cell interactions and in growth and development. Malignant transformation has been shown to be associated with increased expression of TGF-beta. Since bone is the largest storage site and producer of TGF-beta, we speculated on the existence of an autocrine mechanism in osteosarcoma, a malignant bone tumor. Expression of TGF-beta cell surface receptors, effects on growth of TGF-beta and TGF-beta antibodies and production of 2 TGF-beta isoforms were studied in a panel of 7 osteosarcoma cell lines. In contrast to most previous reports on the effects of TGF-beta on osteosarcoma cell growth, we found a mitogenic effect of TGF-beta 1 in 4 of 7 osteosarcoma cell lines. Receptor profiles for TGF-beta were aberrant in 5 of the 7 cell lines tested, and production of TGF-beta 1 and TGF-beta 2 varied among cell lines. Addition of anti-TGF-beta antagonized the effects of endogenous TGF-beta. Our results suggest a potential role of TGF-beta in autocrine growth control of osteosarcoma cells.

  8. Maximising electricity production by controlling the biofilm specific growth rate in microbial fuel cells.

    PubMed

    Ledezma, Pablo; Greenman, John; Ieropoulos, Ioannis

    2012-08-01

    The aim of this work is to study the relationship between growth rate and electricity production in perfusion-electrode microbial fuel cells (MFCs), across a wide range of flow rates by co-measurement of electrical output and changes in population numbers by viable counts and optical density. The experiments hereby presented demonstrate, for the first time to the authors' knowledge, that the anodic biofilm specific growth rate can be determined and controlled in common with other loose matrix perfusion systems. Feeding with nutrient-limiting conditions at a critical flow rate (50.8 mL h(-1)) resulted in the first experimental determination of maximum specific growth rate μ(max) (19.8 day(-1)) for Shewanella spp. MFC biofilms, which is considerably higher than those predicted or assumed via mathematical modelling. It is also shown that, under carbon-energy limiting conditions there is a strong direct relationship between growth rate and electrical power output, with μ(max) coinciding with maximum electrical power production.

  9. SIZ1 controls cell growth and plant development in Arabidopsis through salicylic acid.

    PubMed

    Miura, Kenji; Lee, Jiyoung; Miura, Tomoko; Hasegawa, Paul M

    2010-01-01

    The post-translational conjugation of small ubiquitin-related modifiers (SUMOs) to other proteins is involved in regulation of many processes in eukaryotic development; although its role in plant development is beginning to be dissected. Previously, we demonstrated that the siz1 mutant, which is impaired in SUMO E3 ligase, showed a dwarf-like shoot phenotype with accumulation of salicylic acid (SA), and the expression of nahG, a bacterial salicylate hydroxylase that catabolizes SA, in siz1 reduced the SA level and suppressed dwarfism. Herein, we provide evidence that the SIZ1 gene controls cell division and elongation through regulation of the SA level. Mature siz1-2 and siz1-3 plants exhibited a dwarf-like shoot phenotype that is attributable to decreased leaf cell volume and number relative to the wild type. Cell division and expansion defects caused by siz1 were also suppressed by the expression of nahG. Expression of XTH8 and XTH31, encoding xyloglucan endotransglycosylase/hydrolase, which are thought to facilitate leaf cell expansion, was down-regulated in siz1 leaves. However, reduced XTH8 and XTH31 expression in siz1 plants was restored in nahG siz1-2 plants. These results indicate that SIZ1 regulates cell growth and plant development with regulation of SA accumulation. Also, XTH8 and XTH31 genes may be responsible for reduced leaf cell expansion.

  10. Sprouty2 controls proliferation of palate mesenchymal cells via fibroblast growth factor signaling

    SciTech Connect

    Matsumura, Kaori; Taketomi, Takaharu; Yoshizaki, Keigo; Arai, Shinsaku; Sanui, Terukazu; Yoshiga, Daigo; Yoshimura, Akihiko; Nakamura, Seiji

    2011-01-28

    Research highlights: {yields} Sprouty2-deficient mice exhibit cleft palate as a result of failure of palatal shelf elevation. {yields} We examined palate cell proliferation in Sprouty2-deficient mice. {yields} Palate mesenchymal cell proliferation was increased in Sprouty2 KO mice. {yields} Sprouty2 plays roles in murine palatogenesis by regulating cell proliferation. -- Abstract: Cleft palate is one of the most common craniofacial deformities. The fibroblast growth factor (FGF) plays a central role in reciprocal interactions between adjacent tissues during palatal development, and the FGF signaling pathway has been shown to be inhibited by members of the Sprouty protein family. In this study, we report the incidence of cleft palate, possibly caused by failure of palatal shelf elevation, in Sprouty2-deficient (KO) mice. Sprouty2-deficient palates fused completely in palatal organ culture. However, palate mesenchymal cell proliferation estimated by Ki-67 staining was increased in Sprouty2 KO mice compared with WT mice. Sprouty2-null palates expressed higher levels of FGF target genes, such as Msx1, Etv5, and Ptx1 than WT controls. Furthermore, proliferation and the extracellular signal-regulated kinase (Erk) activation in response to FGF was enhanced in palate mesenchymal cells transfected with Sprouty2 small interfering RNA. These results suggest that Sprouty2 regulates palate mesenchymal cell proliferation via FGF signaling and is involved in palatal shelf elevation.

  11. Cell length growth patterns in fission yeast reveal a novel size control mechanism operating in late G2 phase.

    PubMed

    Horváth, Anna; Rácz-Mónus, Anna; Buchwald, Peter; Sveiczer, Ákos

    2016-09-01

    Because cylindrically shaped fission yeast cells grow exclusively at their tips, cell volume is proportional to length and can be easily monitored by time-lapse microscopy. Here, we analysed the growth pattern of individual cells from several fission yeast strains to determine the growth function that describes them most adequately and to perform size control studies. The growth pattern of most cells during their growth period is best described by a bilinear function (i.e., two linear segments of different growth rates separated by a rate-change point). Linear growth patterns were also observed in several cases, but exponential ones only rarely. Since the bilinear patterns are separated into two segments by a breakpoint, we examined the existence of size control by regression analyses of the appropriate growth parameters in both segments. This confirmed the existence of known size controls in late G1, mid-G2 and late G2 during the fission yeast cycle. The present analyses also revealed that, contrary to the commonly accepted current view, late G2 size control is a general characteristic third event in the cycle. The level of the critical late G2 size that needs to be reached in an individual fission yeast cell is influenced by the growth rate of the cell in a manner similar to budding yeast, suggesting an evolutionary conserved mechanism. The present study of individual cell growth patterns in wild-type and several cell cycle mutant fission yeast strains confirmed that, for most cells, growth is best described by a bilinear function. Three different size control mechanisms were found to operate in the different strains, and, as a novel observation, cell size was always found to be monitored before mitotic onset, irrespective of the existence of any earlier size checkpoints. Studying the pattern of growth and the mechanism of size control helps to clarify the connections between cell growth and division, since their coordination must work properly to maintain size

  12. Transcription controls growth, cell kinetics and cholesterol supply to sustain ACTH responses.

    PubMed

    Menzies, Robert I; Zhao, Xin; Mullins, Linda J; Mullins, John J; Cairns, Carolynn; Wrobel, Nicola; Dunbar, Donald R; Bailey, Matthew A; Kenyon, Christopher J

    2017-10-01

    Chronic ACTH exposure is associated with adrenal hypertrophy and steroidogenesis. The underlying molecular processes in mice have been analysed by microarray, histological and immunohistochemical techniques. Synacthen infused for 2 weeks markedly increased adrenal mass and plasma corticosterone levels. Microarray analysis found greater than 2-fold changes in expression of 928 genes (P < 0.001; 397 up, 531 down). These clustered in pathways involved in signalling, sterol/lipid metabolism, cell proliferation/hypertrophy and apoptosis. Signalling genes included some implicated in adrenal adenomas but also upregulated genes associated with cyclic AMP and downregulated genes associated with aldosterone synthesis. Sterol metabolism genes were those promoting cholesterol supply (Scarb1, Sqle, Apoa1) and disposal (Cyp27a1, Cyp7b1). Oil red O staining showed lipid depletion consistent with reduced expression of genes involved in lipid synthesis. Genes involved in steroidogenesis (Star, Cyp11a1, Cyp11b1) were modestly affected (P < 0.05; <1.3-fold). Increased Ki67, Ccna2, Ccnb2 and Tk1 expression complemented immunohistochemical evidence of a 3-fold change in cell proliferation. Growth arrest genes, Cdkn1a and Cdkn1c, which are known to be active in hypertrophied cells, were increased >4-fold and cross-sectional area of fasciculata cells was 2-fold greater. In contrast, genes associated with apoptosis (eg Casp12, Clu,) were downregulated and apoptotic cells (Tunel staining) were fewer (P < 0.001) and more widely distributed throughout the cortex. In summary, long-term steroidogenesis with ACTH excess is sustained by genes controlling cholesterol supply and adrenal mass. ACTH effects on adrenal morphology and genes controlling cell hypertrophy, proliferation and apoptosis suggest the involvement of different cell types and separate molecular pathways. © 2017 The authors.

  13. Proscillaridin A is cytotoxic for glioblastoma cell lines and controls tumor xenograft growth in vivo

    PubMed Central

    Tchoghandjian, Aurélie; Carré, Manon; Colin, Carole; Jiglaire, Carine Jiguet; Mercurio, Sandy; Beclin, Christophe; Figarella-Branger, Dominique

    2014-01-01

    Glioblastoma is the most frequent primary brain tumor in adults. Because of molecular and cellular heterogeneity, high proliferation rate and significant invasive ability, prognosis of patients is poor. Recent therapeutic advances increased median overall survival but tumor recurrence remains inevitable. In this context, we used a high throughput screening approach to bring out novel compounds with anti-proliferative and anti-migratory properties for glioblastoma treatment. Screening of the Prestwick chemical library® of 1120 molecules identified proscillaridin A, a cardiac glycoside inhibitor of the Na+/K+ ATPase pump, with most significant effects on glioblastoma cell lines. In vitro effects of proscillaridin A were evaluated on GBM6 and GBM9 stem-like cell lines and on U87-MG and U251-MG cell lines. We showed that proscillaridin A displayed cytotoxic properties, triggered cell death, induced G2/M phase blockade in all the glioblastoma cell lines and impaired GBM stem self-renewal capacity even at low concentrations. Heterotopic and orthotopic xenotransplantations were used to confirm in vivo anticancer effects of proscillaridin A that both controls xenograft growth and improves mice survival. Altogether, results suggest that proscillaridin A is a promising candidate as cancer therapies in glioblastoma. This sustains previous reports showing that cardiac glycosides act as anticancer drugs in other cancers. PMID:25400117

  14. Epigenetic Regulation of Axonal Growth of Drosophila Pacemaker Cells by Histone Acetyltransferase Tip60 Controls Sleep

    PubMed Central

    Pirooznia, Sheila K.; Chiu, Kellie; Chan, May T.; Zimmerman, John E.; Elefant, Felice

    2012-01-01

    Tip60 is a histone acetyltransferase (HAT) enzyme that epigenetically regulates genes enriched for neuronal functions through interaction with the amyloid precursor protein (APP) intracellular domain. However, whether Tip60-mediated epigenetic dysregulation affects specific neuronal processes in vivo and contributes to neurodegeneration remains unclear. Here, we show that Tip60 HAT activity mediates axonal growth of the Drosophila pacemaker cells, termed “small ventrolateral neurons” (sLNvs), and their production of the neuropeptide pigment-dispersing factor (PDF) that functions to stabilize Drosophila sleep–wake cycles. Using genetic approaches, we show that loss of Tip60 HAT activity in the presence of the Alzheimer’s disease-associated APP affects PDF expression and causes retraction of the sLNv synaptic arbor required for presynaptic release of PDF. Functional consequence of these effects is evidenced by disruption of the sleep–wake cycle in these flies. Notably, overexpression of Tip60 in conjunction with APP rescues these sleep–wake disturbances by inducing overelaboration of the sLNv synaptic terminals and increasing PDF levels, supporting a neuroprotective role for dTip60 in sLNv growth and function under APP-induced neurodegenerative conditions. Our findings reveal a novel mechanism for Tip60 mediated sleep–wake regulation via control of axonal growth and PDF levels within the sLNv-encompassing neural network and provide insight into epigenetic-based regulation of sleep disturbances observed in neurodegenerative diseases like Alzheimer’s disease. PMID:22982579

  15. Use of a small molecule cell cycle inhibitor to control cell growth and improve specific productivity and product quality of recombinant proteins in CHO cell cultures.

    PubMed

    Du, Zhimei; Treiber, David; McCarter, John D; Fomina-Yadlin, Dina; Saleem, Ramsey A; McCoy, Rebecca E; Zhang, Yuling; Tharmalingam, Tharmala; Leith, Matthew; Follstad, Brian D; Dell, Brad; Grisim, Brent; Zupke, Craig; Heath, Carole; Morris, Arvia E; Reddy, Pranhitha

    2015-01-01

    The continued need to improve therapeutic recombinant protein productivity has led to ongoing assessment of appropriate strategies in the biopharmaceutical industry to establish robust processes with optimized critical variables, that is, viable cell density (VCD) and specific productivity (product per cell, qP). Even though high VCD is a positive factor for titer, uncontrolled proliferation beyond a certain cell mass is also undesirable. To enable efficient process development to achieve consistent and predictable growth arrest while maintaining VCD, as well as improving qP, without negative impacts on product quality from clone to clone, we identified an approach that directly targets the cell cycle G1-checkpoint by selectively inhibiting the function of cyclin dependent kinases (CDK) 4/6 with a small molecule compound. Results from studies on multiple recombinant Chinese hamster ovary (CHO) cell lines demonstrate that the selective inhibitor can mediate a complete and sustained G0/G1 arrest without impacting G2/M phase. Cell proliferation is consistently and rapidly controlled in all recombinant cell lines at one concentration of this inhibitor throughout the production processes with specific productivities increased up to 110 pg/cell/day. Additionally, the product quality attributes of the mAb, with regard to high molecular weight (HMW) and glycan profile, are not negatively impacted. In fact, high mannose is decreased after treatment, which is in contrast to other established growth control methods such as reducing culture temperature. Microarray analysis showed major differences in expression of regulatory genes of the glycosylation and cell cycle signaling pathways between these different growth control methods. Overall, our observations showed that cell cycle arrest by directly targeting CDK4/6 using selective inhibitor compound can be utilized consistently and rapidly to optimize process parameters, such as cell growth, qP, and glycosylation profile in

  16. Use of a small molecule cell cycle inhibitor to control cell growth and improve specific productivity and product quality of recombinant proteins in CHO cell cultures

    PubMed Central

    Du, Zhimei; Treiber, David; McCarter, John D; Fomina-Yadlin, Dina; Saleem, Ramsey A; McCoy, Rebecca E; Zhang, Yuling; Tharmalingam, Tharmala; Leith, Matthew; Follstad, Brian D; Dell, Brad; Grisim, Brent; Zupke, Craig; Heath, Carole; Morris, Arvia E; Reddy, Pranhitha

    2015-01-01

    The continued need to improve therapeutic recombinant protein productivity has led to ongoing assessment of appropriate strategies in the biopharmaceutical industry to establish robust processes with optimized critical variables, that is, viable cell density (VCD) and specific productivity (product per cell, qP). Even though high VCD is a positive factor for titer, uncontrolled proliferation beyond a certain cell mass is also undesirable. To enable efficient process development to achieve consistent and predictable growth arrest while maintaining VCD, as well as improving qP, without negative impacts on product quality from clone to clone, we identified an approach that directly targets the cell cycle G1-checkpoint by selectively inhibiting the function of cyclin dependent kinases (CDK) 4/6 with a small molecule compound. Results from studies on multiple recombinant Chinese hamster ovary (CHO) cell lines demonstrate that the selective inhibitor can mediate a complete and sustained G0/G1 arrest without impacting G2/M phase. Cell proliferation is consistently and rapidly controlled in all recombinant cell lines at one concentration of this inhibitor throughout the production processes with specific productivities increased up to 110 pg/cell/day. Additionally, the product quality attributes of the mAb, with regard to high molecular weight (HMW) and glycan profile, are not negatively impacted. In fact, high mannose is decreased after treatment, which is in contrast to other established growth control methods such as reducing culture temperature. Microarray analysis showed major differences in expression of regulatory genes of the glycosylation and cell cycle signaling pathways between these different growth control methods. Overall, our observations showed that cell cycle arrest by directly targeting CDK4/6 using selective inhibitor compound can be utilized consistently and rapidly to optimize process parameters, such as cell growth, qP, and glycosylation profile in

  17. Self-assembled two-dimensional thermoresponsive microgel arrays for cell growth/detachment control.

    PubMed

    Xia, Yongqing; He, Xinlong; Cao, Meiwen; Wang, Xiaojuan; Sun, Yawei; He, Hua; Xu, Hai; Lu, Jian Ren

    2014-11-10

    Monodisperse poly(N-isopropylacrylamide-styrene) (PNIPAAmSt) microgels with different St/NIPAAm ratios have been synthesized via a one-step surfactant-free emulsion polymerization process. The resulting microgel dispersions were used to fabricate 2D arrays on the surface of silicon wafers/glass coverslips through dip coating. The thermal responsiveness of the PNIPAAmSt microgel arrays was examined by spectroscopic ellipsometry and the results unraveled that the thermoresponsive behavior of the arrays was highly consistent with the microgels dispersed in the bulk, showing high dependence on the content of styrene. The structure of the films varied from nonclose-packed 2D arrays to close-packed 2D arrays, depending on both properties of the microgels and array fabrication conditions. When the weight ratio of styrene was below 40%, the microgel arrays demonstrated effective control for cell growth and detachment across their volume phase transition temperatures (around 28 °C). The extent of swelling of the microgels was the key factor to determine whether the cells could detach from the film easily. For the rather close-packed 2D arrays prepared by the same kind of PNIPAAmSt microgels, the gaps between microgel particles showed no obvious effect on the rate of cell detachment.

  18. Insulin-Like Growth Factor-1 Controls Type 2 T Cell-Independent B Cell Response

    DTIC Science & Technology

    2005-01-01

    cells with anti-CD43 Ab coupled to magnetic beads and MACS columns ( Miltenyi Biotec) as described previously (34), plated on 96-well plates at 105 cells...CD86 in re- sponse to B cell activation. Cross-linking of IgM, CD40 (Ab-me- diated), or CD14 (with LPS from E. coli) led to increased expres- sion of

  19. Mediators in cell growth and differentiation

    SciTech Connect

    Ford, R.J.; Maizel, A.L.

    1985-01-01

    This book contains papers divided among seven sections. The section headings are: Cell Cycle and Control of Cell Growth, Growth Factors for Nonlymphoid Cells, Colony-Stimulating Factors, Stem Cells and Hematopoiesis, Lymphoid Growth Factors, Growth Factors in Neoplasia, Interferon, and Differentiation in Normal and Neoplastic Cells.

  20. Ets-1 controls breast cancer cell balance between invasion and growth.

    PubMed

    Furlan, Alessandro; Vercamer, Chantal; Bouali, Fatima; Damour, Isabelle; Chotteau-Lelievre, Anne; Wernert, Nicolas; Desbiens, Xavier; Pourtier, Albin

    2014-11-15

    Ets-1 overexpression in human breast cancers is associated with invasiveness and poor prognosis. By overexpressing Ets-1 or a dominant negative mutant in MMT breast cancer cells, we previously highlighted the key role of Ets-1 in coordinating multiple invasive features of these cells. Interestingly, we also noticed that Ets-1 decreased the density of breast cancer cells cultured in three-dimensional extracellular matrix gels. The 3D context was instrumental to this phenomenon, as such downregulation was not observed in cells grown on two-dimensional plastic or matrix-coated dishes. Ets-1 overexpression was deleterious to anchorage-independent growth of MMT cells in soft agar, a standard model for in vitro tumorigenicity. The relevance of this mechanism was confirmed in vivo, during primary tumor growth and in a metastatic assay of lung colonization. In these models, Ets-1 was associated with epithelial-to-mesenchymal transition features and modulated the ratio of Ki67-positive cells, while hardly affecting in vivo apoptotic cell death. Finally, siRNA-mediated knockdown of Ets-1 in human breast cancer cell lines also decreased colony growth, both in anchorage-independent assays and 3D extracellular matrix cultures. These in vitro and in vivo observations shed light on an unsuspected facet of Ets-1 in breast tumorigenesis. They show that while promoting malignancy through the acquisition of invasive features, Ets-1 also attenuates breast tumor cell growth and could therefore repress the growth of primary tumors and metastases. This work also demonstrates that 3D models may reveal mechanisms of tumor biology that are cryptic in standard 2D models. © 2014 UICC.

  1. Functional role of glycosphingolipids and gangliosides in control of cell adhesion, motility, and growth, through glycosynaptic microdomains.

    PubMed

    Regina Todeschini, Adriane; Hakomori, Sen-itiroh

    2008-03-01

    At cell surface microdomains, glycosyl epitopes, carried either by glycosphingolipids, N- or O-linked oligosaccharides, are recognized by carbohydrate-binding proteins or complementary carbohydrates. In both cases, the carbohydrate epitopes may be clustered with specific signal transducers, tetraspanins, adhesion receptors or growth factor receptors. Through this framework, carbohydrates can mediate cell signaling leading to changes in cellular phenotype. Microdomains involved in carbohydrate-dependent cell adhesion inducing cell activation, motility, and growth are termed "glycosynapse". In this review a historical synopsis of glycosphingolipids-enriched microdomains study leading to the concept of glycosynapse is presented. Examples of glycosynapse as signaling unit controlling the tumor cell phenotype are discussed in three contexts: (i) Cell-to-cell adhesion mediated by glycosphingolipids-to-glycosphingolipids interaction between interfacing glycosynaptic domains, through head-to-head (trans) carbohydrate-to-carbohydrate interaction. (ii) Functional role of GM3 complexed with tetraspanin CD9, and interaction of such complex with integrins, or with fibroblast growth factor receptor, to control tumor cell phenotype and its reversion to normal cell phenotype. (iii) Inhibition of integrin-dependent Met kinase activity by GM2/tetraspanin CD82 complex in glycosynaptic microdomain. Data present here suggest that the organizational status of glycosynapse strongly affects cellular phenotype influencing tumor cell malignancy.

  2. Density-dependent regulation of growth of BSC-1 cells in cell culture: Control of growth by low molecular weight nutrients

    PubMed Central

    Holley, Robert W.; Armour, Rosemary; Baldwin, Julia H.

    1978-01-01

    BSC-1 cells, epithelial cells of African green monkey kidney origin, show pronounced density-dependent regulation of growth in cell culture. Growth of the cells is rapid to a density of approximately 1.5 × 105 cells/per cm2 in Dulbecco-modified Eagle's medium supplemented with 10% calf serum. Above this “saturation density,” growth is much slower. It has been found that the glucose concentration in the culture medium is important in determining the “saturation density.” If the glucose concentration is increased 4-fold, the “saturation density” increases approximately 50%. Reduction of the “saturation density” of BSC-1 cells is also possible by decreasing the concentrations of low molecular weight nutrients in the culture medium. In medium supplemented with 0.1% calf serum, decreasing the concentrations of all of the organic constituents of the medium, from the high levels present in Dulbecco-modified Eagle's medium to concentrations near physiological levels, decreases the “saturation density” by approximately half. The decreased “saturation density” is not the result of lowering the concentration of any single nutrient but rather results from reduction of the concentrations of several nutrients. When the growth of BSC-1 cells is limited by low concentrations of all of the nutrients, some stimulation of growth results from increasing, separately, the concentrations of individual groups of nutrients, but the best growth stimulation is obtained by increasing the concentrations of all of the nutrients. The “wound healing” phenomenon, one manifestation of density-dependent regulation of growth in cell culture, is abolished by lowering the concentration of glutamine in the medium. Density-dependent regulation of growth of BSC-1 cells in cell culture thus appears to be a complex phenomenon that involves an interaction of nutrient concentrations with other regulatory factors. PMID:272650

  3. Growth control and ribosomopathies.

    PubMed

    Teng, Teng; Thomas, George; Mercer, Carol A

    2013-02-01

    Ribosome biogenesis and protein synthesis are two of the most energy consuming processes in a growing cell. Moreover, defects in their molecular components can alter the pattern of gene expression. Thus it is understandable that cells have developed a surveillance system to monitor the status of the translational machinery. Recent discoveries of causative mutations and deletions in genes linked to ribosome biogenesis have defined a group of similar pathologies termed ribosomopathies. Over the past decade, much has been learned regarding the relationship between growth control and ribosome biogenesis. The discovery of extra-ribosomal functions of several ribosome proteins and their regulation of p53 levels has provided a link from ribosome impairment to cell cycle regulation. Yet, evidence suggesting p53 and/or Hdm2 independent pathways also exists. In this review, we summarize recent advances in understanding the mechanisms underlying the pathologies of ribosomopathies and discuss the relationship between ribosome production and tumorigenesis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. The blue light receptor Phototropin 1 suppresses lateral root growth by controlling cell elongation.

    PubMed

    Moni, A; Lee, A-Y; Briggs, W R; Han, I-S

    2015-01-01

    We investigated the relationship between the blue light receptor phototropin 1 (phot1) and lateral root growth in Arabidopsis thaliana seedlings. Fluorescence and confocal microscopy images, as well as PHOT1 mRNA expression studies provide evidence that it is highly expressed in the elongation zone of lateral roots where auxin is accumulating. However, treatment with the auxin transport inhibitor N-1-naphthylphthalamic acid significantly reduced PHOT1 expression in this zone. In addition, PHOT1 expression was higher in darkness than in light. The total number of lateral roots was higher in the phot1 mutant than in wild-type Arabidopsis. Cells in the elongation zone of lateral roots of the phot1 mutant were longer than those of wild-type lateral roots. These findings suggest that PHOT1 plays a role(s) in elongation of lateral roots through the control of an auxin-related signalling pathway. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  5. [Investigation of systemic control of plant cell division and differentiation in the model of tumor growth in radish].

    PubMed

    Lutova, L A; Dolgikh, E A; Dodueva, I E; Osipova, M A; Il'ina, E L

    2008-08-01

    The study addresses the control of plant cell division and differentiation using the model of tumor-forming lines of radish. Expression of the genes involved in control of the cell cycle (CycD3), maintenance of meristematic cell activity (STM, WUS, and KNAT1), and primary response to cytokinin (ARR) was studied in inbred radish lines characterized by tumor growth at different stages of development. The influence of exogenic cytokinin on the expression of the genes of interest is analyzed. The possible role of the CycD3, KNAT1, STM, WUS, and ARR5 in tumor formation in radish is discussed.

  6. Induction of ribosomal subunits misassembly by antisense RNAs to control cell growth.

    PubMed

    Mangiarotti, G

    2000-08-25

    The assembly of ribosomal subunits starting from free ribosomal RNA and protein of Dictyostelium discoideum was induced in vitro in the presence of several oligoribonucleotides complementary to defined sequences of ribosomal RNA. The reconstituted particles had a full complement of ribosomal proteins, but did not function in an in vitro protein synthesis system and were disassembled following interaction with mRNA. The same result was obtained in vivo by fusing the oligodeossiribonucleotides coding for the selected oligoribonucleotides to the promoter of the gene coding for contact site A protein. This gene is expressed only in the first part of development. Transfected growing cells, transferred in developing buffer in the presence of pulses of cAMP, accumulated significant amounts of the oligoribonucleotides. When retransferred to the growth medium, they grew progressively more slowly, until their doubling time doubled, apparently due to the availability of a limiting amount of functional ribosomes. To avoid disassembly of misassembled subunits (G. Mangiarotti et al., 1997, J. Biol. Chem. 272, 27818-27822), two oligoribonucleotides complementary to sequences present at the 5' ends of pre-17S and pre-26S RNAs were also induced to accumulate during early development with the same technique. When transfected cells were retransferred to the growth medium, their rate of growth declined rapidly to zero and cells died, apparently because they were unable to disassemble misassembled ribosomal subunits and avoid their entry into polyribosomes. This technique to perturb protein synthesis, arrest cell growth, and cause cell suicide will be tested in abnormally growing animal cells.

  7. Control of growth and squamous differentiation in normal human bronchial epithelial cells by chemical and biological modifiers and transferred genes.

    PubMed Central

    Pfeifer, A M; Lechner, J F; Masui, T; Reddel, R R; Mark, G E; Harris, C C

    1989-01-01

    The majority of human lung cancers arise from bronchial epithelial cells. The normal pseudostratified bronchial epithelium is composed of basal, mucous, and ciliated cells. This multi-differentiated epithelium usually responds to xenobiotics and physical injury by undergoing basal cell hyperplasia, mucous cell hyperplasia, and squamous metaplasia. One step of the multistage process of carcinogenesis is thought to involve aberrations in control of the squamous metaplastic processes. Decreased responsiveness to regulators of terminal squamous differentiation may confer a selective clonal expansion advantage to an initiated cell. We studied the effects of endogenous [e.g., transforming growth factor beta 1 (TGF-beta 1) and serum] and exogenous [e.g., 12-O-tetradecanoyl-13-phorbol-acetate (TPA), tobacco smoke condensate, and aldehydes] modifiers of normal human bronchial epithelial (NHBE) cell in a serum-free culture system. NHBE cells are growth inhibited by all of these compounds and induced to undergo squamous differentiation by TGF-beta 1 or TPA. In contrast, lung carcinoma cell lines are relatively resistant to inducers of terminal squamous differentiation which may provide them with a selective growth advantage. Chemical agents and activated protooncogenes (ras,raf,myc) altered the response to endogenous and exogenous inducers of squamous differentiation and caused extended cellular lifespan, aneuploidy, and/or tumorigenicity. The data suggest a close relationship between dysregulation of terminal differentiation pathways and neoplastic transformation of human bronchial epithelial cells. PMID:2538323

  8. The receptor-like kinases GSO1 and GSO2 together regulate root growth in Arabidopsis through control of cell division and cell fate specification.

    PubMed

    Racolta, Adriana; Bryan, Anthony C; Tax, Frans E

    2014-02-01

    The root apical meristem of Arabidopsis is established post-embryonically as the main source of root cells, and its activity is maintained by complex bidirectional signaling between stem cells and mature cells. The receptor-like kinases GASSHO1 (GSO1) and GSO2 have been shown to regulate aerial epidermal function and seedling growth in Arabidopsis. Here we show that gso1; gso2 seedlings also have root growth and patterning defects. Analyses of mutant root morphology indicate abnormal numbers of cells in longitudinal files and radial cell layers, as well as aberrant stem cell division planes. gso1; gso2 double mutants misexpress markers for stem cells and differentiated root cell types. In addition, gso1; gso2 root growth defects, but not marker missexpression or patterning phenotypes, are rescued by growth on media containing metabolizable sugars. We conclude that GSO1 and GSO2 function together in intercellular signaling to positively regulate cell proliferation, differentiation of root cell types, and stem cell identity. In addition, GSO1 and GSO2 control seedling root growth by modulating sucrose response after germination. Copyright © 2013 Wiley Periodicals, Inc.

  9. Diffusion controlled ice growth with soft impingement inside biological cells during freezing.

    PubMed

    Chen, Cong; Li, Weizhong

    2008-01-01

    An iterative method has been proposed to determine the relationship between the temperature depression of intracellular ice formation (IIF) and the equilibrium melting point depression for initial cryoprotective agent (CPA) concentrations larger than 1.5M. Using the iterative method coupling with a water transport model for freezing induced cell dehydration and intracellular ice growth, the temperature of IIF has been determined. The new model of temperature of IIF has been applied to predict nucleation parameters at various temperature and initial CPA concentrations according to Karlsson's approach. A geometrical model of soft impingement proposed by Bruna has been incorporated into Karlsson's diffusion limited crystal growth model to include the effect of soft impingement. The new crystal growth model has been verified by a comparison between the predicted critical cooling rates for vitrification with the reported values in literature. With the new crystal growth model, it has been found that the limiting value of the crystallized volume fraction increases as cooling progresses and decreases as the initial CPA concentration increases. A comparison of simulated crystallized volume fractions when soft impingement, hard impingement and no corrections are used has also been made and the result shows that soft impingement could not be omitted in the prediction of intracellular ice formation and growth, especially when the final crystallized volume fraction is larger than 0.1.

  10. Hair follicle growth controls.

    PubMed

    Stenn, K S; Combates, N J; Eilertsen, K J; Gordon, J S; Pardinas, J R; Parimoo, S; Prouty, S M

    1996-10-01

    Research in hair biology has embarked in the pursuit for molecules that control hair growth. Many molecules already have been associated with the controls of hair patterning, hair maturation, and hair cycling and differentiation. Knowing how these molecules work gives us the tools for understanding and treating patients with hair disorders.

  11. Adoptive Transfer of Tumor-Specific Tc17 Effector T Cells Controls the Growth of B16 Melanoma in Mice

    PubMed Central

    de la Luz Garcia-Hernandez, Maria; Hamada, Hiromasa; Reome, Joyce B.; Misra, Sara K.; Tighe, Michael P.; Dutton, Richard W.

    2010-01-01

    In vitro generated OVA-specific IL-17–producing CD8 T effector cells (Tc17) from OT-1 mice, adoptively transferred into B16-OVA tumor-bearing mice, controlled tumor growth in early and late stage melanoma. IL-17, TNF, and IFN-γ from the Tc17 effectors all played a role in an enhanced recruitment of T cells, neutrophils, and macrophages to the tumor. In addition, Tc17 cells and recently recruited, activated neutrophils produced further chemokines, including CCL3, CCL4, CCL5, CXCL9, and CXCL10, responsible for the attraction of type 1 lymphocytes (Th1 and Tc1) and additional neutrophils. Neutrophils were rapidly attracted to the tumor site by an IL-17 dependent mechanism, but at later stages the induction of the chemokine CXCL2 by Tc17-derived TNF and IFN-γ contributed to sustain neutrophil recruitment. Approximately 10–50 times as many Tc17 effectors were required compared with Tc1 effectors to exert the same level of control over tumor growth. The recruitment of neutrophils was more prominent when Tc17 rather than Tc1 were used to control tumor and depletion of neutrophils resulted in a diminished capacity to control tumor growth. PMID:20237297

  12. Control of cell motility by interaction of gangliosides, tetraspanins, and epidermal growth factor receptor in A431 versus KB epidermoid tumor cells.

    PubMed

    Park, Seung-Yeol; Yoon, Seon-Joo; Freire-de-Lima, Leonardo; Kim, Jung-Hoe; Hakomori, Sen-itiroh

    2009-08-17

    Growth of epidermoid carcinoma cell lines, A431 and KB, has been known to be controlled by the interaction of epidermal growth factor (EGF) and its receptor (EGFR) with tyrosine kinase. Ganglioside GM3 was previously found to interact with EGFR and to inhibit EGFR tyrosine kinase. However, motility of these cells, controlled by EGFR and ganglioside, was not studied. The present study is focused on the control mechanism of the motility of these cells through interaction of ganglioside, tetraspanin (TSP), and EGFR. Key results are as follows: (i) The level of EGFR expressed in A431 cells is approximately 6 times higher than that expressed in KB cells, and motility of A431 cells is also much higher than that of KB cells, yet growth of A431 cells is either not affected or is inhibited by EGF. In contrast, growth of KB cells is enhanced by EGF. (ii) Levels of TSPs (CD9, CD82, and CD81) expressed in A431 cells are much higher than those expressed in KB cells, and TSPs expressed in A431 cells are reduced by treatment of cells with EtDO-P4, which inhibits the synthesis of glycosphingolipids (GSLs) and gangliosides. (iii) These TSPs are co-immunoprecipitated with EGFR in both A431 and KB cells, indicating that TSPs are closely associated with EGFR. (iv) High motility of A431 cells is greatly reduced, while low motility of KB cells is not affected, by treatment of cells with EtDO-P4. These results, taken together, suggest that there is a close correlation between high motility of A431 cells and high expression of EGFR and TSPs, and between ganglioside GM3/GM2 and TSP. A similar correlation was suggested between the low motility of KB cells and low levels of EGFR and TSP. The correlation between high motility and high level of EGFR with the ganglioside-TSP complex in A431 cells is unique. This is in contrast to our previous studies that indicate that motility of many types of tumor cells is inhibited by a high level of CD9 or CD82, together with growth factor receptors and

  13. Electrically conducting polymers can noninvasively control the shape and growth of mammalian cells.

    PubMed Central

    Wong, J Y; Langer, R; Ingber, D E

    1994-01-01

    Electrically conducting polymers are novel in that their surface properties, including charge density and wettability, can be reversibly changed with an applied electrical potential. Such properties might render conducting polymers unique for biological applications. However, the majority of research on conducting polymers has been carried out under nonbiological conditions. We synthesized optically transparent polypyrrole thin films and studied them in environments suitable for protein adsorption and mammalian cell culture. In vitro studies demonstrated that extracellular matrix molecules, such as fibronectin, adsorb efficiently onto polypyrrole thin films and support cell attachment under serum-free conditions. When aortic endothelial cells were cultured on fibronectin-coated polypyrrole (oxidized) in either chemically defined medium or the presence of serum, cells spread normally and synthesized DNA. In contrast, when the polymer was switched to its neutral state by applying an electrical potential, both cell extension and DNA synthesis were inhibited without affecting cell viability. Application of a similar electrical potential to cells cultured on indium tin oxide surfaces had no effect on cell shape or function. These data suggest that electrically conducting polymers may represent a type of culture substrate which could provide a noninvasive means to control the shape and function of adherent cells, independent of any medium alteration. Images PMID:8159724

  14. Molecular Control of Cell Growth During Gravity Responses of Maize Seedlings

    NASA Technical Reports Server (NTRS)

    Cosgrove, Daniel J.

    2003-01-01

    Gravity influences plants in many ways via its physical effects on the convective flows of gases and liquids, the buoyancy and sedimentation of cellular organelles, and the distribution of mechanical stresses in weight-bearing structures. These physical effects lead to a variety of reactions and adaptive developmental responses in plants. Perhaps the best-studied plant gravity response is gravitropism - the "homing in" of growing organs towards a particular angle with respect to gravity. Most plants respond to gravity by gravitropic bending of roots downwards and stems upwards. Such gravitropic bending arises from differential cell growth on the two sides of the bending organ. For this project we hypothesized that such growth differences arise from differences in expansin activity, which come about because of organ-level asymmetries of H+ efflux and expansin export to the wall.

  15. Controlling growth and electrical connectivity of neuronal cells patterned on surfaces

    NASA Astrophysics Data System (ADS)

    Beighley, Ross; Spedden, Elise; White, James; Staii, Cristian

    2012-02-01

    In the developing brain biochemical and geometrical cues are an essential source of information used by neurons when wiring up the nervous system. However, our current understanding of the mechanisms by which various guidance factors control the path that growing axons/dendrites follow to reach their targets and form functional electrical connections remains qualitative. A current limitation for the study of neural network formation is the ability to precisely control the growth and interconnectivity of small numbers of neurons. Here we present a combined Atomic Force Microscopy - Fluorescence Spectroscopy approach for patterning neurons on 2-dimensional substrates and precisely controlling their location, growth and interconnectivity. We demonstrate that this approach allows one to: a) form simple neuronal circuits in well-controlled geometries; b) guide the formation of functional synapses between neurons, and c) measure the electrical activity of small groups of neurons. We also discuss the implications of these results for our current understanding of the fundamental mechanisms that govern the development of electrical connections between neurons.

  16. Growth control of genetically modified cells using an antibody/c-Kit chimera.

    PubMed

    Kaneko, Etsuji; Kawahara, Masahiro; Ueda, Hiroshi; Nagamune, Teruyuki

    2012-05-01

    Gene therapy has been regarded as an innovative potential treatment against serious congenital diseases. However, applications of gene therapy remain limited, partly because its clinical success depends on therapeutic gene-transduced cells acquiring a proliferative advantage. To address this problem, we have developed the antigen-mediated genetically modified cell amplification (AMEGA) system, which uses chimeric receptors to enable the selective proliferation of gene-transduced cells. In this report, we describe mimicry of c-Kit signaling and its application to the AMEGA system. We created an antibody/c-Kit chimera in which the extracellular domain of c-Kit is replaced with an anti-fluorescein single-chain Fv antibody fragment and the extracellular D2 domain of the erythropoietin receptor. A genetically modified mouse pro-B cell line carrying this chimera showed selective expansion in the presence of fluorescein-conjugated BSA (BSA-FL) as a growth inducer. By further engineering the transmembrane domain of the chimera to reduce interchain interaction we attained stricter ligand-dependency. Since c-Kit is an important molecule in the expansion of hematopoietic stem cells (HSCs), this antibody/c-Kit chimera could be a promising tool for gene therapy targeting HSCs. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  17. The Spatiotemporal Control of Osteoblast Cell Growth, Behavior, and Function Dictated by Nanostructured Stainless Steel Artificial Microenvironments.

    PubMed

    Dhawan, Udesh; Pan, Hsu-An; Shie, Meng-Je; Chu, Ying Hao; Huang, Guewha S; Chen, Po-Chun; Chen, Wen Liang

    2017-12-01

    The successful application of a nanostructured biomaterial as an implant is strongly determined by the nanotopography size triggering the ideal cell response. Here, nanoporous topography on 304L stainless steel substrates was engineered to identify the nanotopography size causing a transition in the cellular characteristics, and accordingly, the design of nanostructured stainless steel surface as orthopedic implants is proposed. A variety of nanopore diameters ranging from 100 to 220 nm were fabricated by one-step electrolysis process and collectively referred to as artificial microenvironments. Control over the nanopore diameter was achieved by varying bias voltage. MG63 osteoblasts were cultured on the nanoporous surfaces for different days. Immunofluorescence (IF) and scanning electron microscopy (SEM) were performed to compare the modulation in cell morphologies and characteristics. Osteoblasts displayed differential growth parameters and distinct transition in cell behavior after nanopore reached a certain diameter. Nanopores with 100-nm diameter promoted cell growth, focal adhesions, cell area, viability, vinculin-stained area, calcium mineralization, and alkaline phosphatase activity. The ability of these nanoporous substrates to differentially modulate the cell behavior and assist in identifying the transition step will be beneficial to biomedical engineers to develop superior implant geometries, triggering an ideal cell response at the cell-nanotopography interface.

  18. Radical Decisions in Cancer: Redox Control of Cell Growth and Death

    PubMed Central

    Sainz, Rosa M.; Lombo, Felipe; Mayo, Juan C.

    2012-01-01

    Free radicals play a key role in many physiological decisions in cells. Since free radicals are toxic to cellular components, it is known that they cause DNA damage, contribute to DNA instability and mutation and thus favor carcinogenesis. However, nowadays it is assumed that free radicals play a further complex role in cancer. Low levels of free radicals and steady state levels of antioxidant enzymes are responsible for the fine tuning of redox status inside cells. A change in redox state is a way to modify the physiological status of the cell, in fact, a more reduced status is found in resting cells while a more oxidative status is associated with proliferative cells. The mechanisms by which redox status can change the proliferative activity of cancer cells are related to transcriptional and posttranscriptional modifications of proteins that play a critical role in cell cycle control. Since cancer cells show higher levels of free radicals compared with their normal counterparts, it is believed that the anti-oxidative stress mechanism is also increased in cancer cells. In fact, the levels of some of the most important antioxidant enzymes are elevated in advanced status of some types of tumors. Anti-cancer treatment is compromised by survival mechanisms in cancer cells and collateral damage in normal non-pathological tissues. Though some resistance mechanisms have been described, they do not yet explain why treatment of cancer fails in several tumors. Given that some antitumoral treatments are based on the generation of free radicals, we will discuss in this review the possible role of antioxidant enzymes in the survival mechanism in cancer cells and then, its participation in the failure of cancer treatments. PMID:24213319

  19. Shear- vs. nanotopography-guided control of growth of endothelial cells on RGD-nanoparticle-nanowell arrays

    PubMed Central

    2013-01-01

    Endothelialization of therapeutic cardiovascular implants is essential for their intravascular hemocompatibility. We previously described a novel nanowell-RGD-nanoparticle ensemble, which when applied to surfaces led to enhanced endothelialization and retention under static conditions and low flow rates. In the present study we extend our work to determine the interrelated effects of flow rate and the orientation of ensemble-decorated surface arrays on the growth, adhesion and morphology of endothelial cells. Human umbilical vascular endothelial cells (HUVECs) were grown on array surfaces with either 1 μm × 5 μm spacing (“parallel to flow”) and 5 μm × 1 μm spacing (“perpendicular to flow”) and were exposed to a range of shear stress of (0 to 4.7 ± 0.2 dyn·cm-2 ), utilizing a pulsatile flow chamber. Under physiological flow (4.7 ± 0.2 dyn·cm-2), RGD-nanoparticle-nanowell array patterning significantly enhanced cell adhesion and spreading compared with control surfaces and with static conditions. Furthermore, improved adhesion coincided with higher alignment to surface patterning, intimating the importance of interaction and response to the array surface as a means of resisting flow detachment. Under sub-physiological condition (1.7 ± 0.3 dyn·cm-2; corresponding to early angiogenesis), nanowell-nanoparticle patterning did not provide enhanced cell growth and adhesion compared with control surfaces. However, it revealed increased alignment along the direction of flow, rather than the direction of the pattern, thus potentially indicating a threshold for cell guidance and related retention. These results could provide a cue for controlling cell growth and alignment under varying physiological conditions. PMID:23607894

  20. Thermoresponsive Substrates Used for the Growth and Controlled Differentiation of Human Mesenchymal Stem Cells.

    PubMed

    Fan, Xingliang; Nash, Maria E; Gorelov, Alexander V; Barry, Frank P; Shaw, Georgina; Rochev, Yury A

    2015-08-24

    This communication outlines the advances made in the development of thermoresponsive substrates for human mesenchymal stem cell (hMSC) expansion and subsequent controlled specific and multilineage differentiation from a previous study performed by this group. Previously, the development of an inexpensive and technically accessible method for hMSC expansion and harvesting was reported, using the solvent casting deposition method and thermoresponsive poly(N-isopropylacrylamide). Here, the logical continuation of this work is reported with the multipassage expansion of hMSCs with phenotypic maintenance followed by induced adipogenic, osteogenic, and chondrogenic differentiation. Interestingly, 1 μm thick solvent cast films are not only capable of hosting an expanding population of phenotypically preserved hMSCs similar to tissue culture plastic controls, but also the cells detached via temperature control better maintain their ability to differentiate compared to conventionally trypsinized cells. This approach to hMSC expansion and differentiation can be highly attractive to stem cell researchers where clinical therapies have seen a collective deviation away from the employment of animal derived products such as proteolytic trypsin. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Sema6A and Mical1 control cell growth and survival of BRAFV600E human melanoma cells

    PubMed Central

    Loria, Rossella; Bon, Giulia; Perotti, Valentina; Gallo, Enzo; Bersani, Ilaria; Baldassari, Paola; Porru, Manuela; Leonetti, Carlo; Di Carlo, Selene; Visca, Paolo; Brizzi, Maria Felice; Anichini, Andrea; Mortarini, Roberta; Falcioni, Rita

    2015-01-01

    We used whole genome microarray analysis to identify potential candidate genes with differential expression in BRAFV600E vs NRASQ61R melanoma cells. We selected, for comparison, a peculiar model based on melanoma clones, isolated from a single tumor characterized by mutually exclusive expression of BRAFV600E and NRASQ61R in different cells. This effort led us to identify two genes, SEMA6A and MICAL1, highly expressed in BRAF-mutant vs NRAS-mutant clones. Real-time PCR, Western blot and immunohistochemistry confirmed preferential expression of Sema6A and Mical1 in BRAFV600E melanoma. Sema6A is a member of the semaphorin family, and it complexes with the plexins to regulate actin cytoskeleton, motility and cell proliferation. Silencing of Sema6A in BRAF-mutant cells caused cytoskeletal remodeling, and loss of stress fibers, that in turn induced cell death. Furthermore, Sema6A depletion caused loss of anchorage-independent growth, inhibition of chemotaxis and invasion. Forced Sema6A overexpression, in NRASQ61R clones, induced anchorage-independent growth, and a significant increase of invasiveness. Mical1, that links Sema/PlexinA signaling, is also a negative regulator of apoptosis. Indeed, Mical-1 depletion in BRAF mutant cells restored MST-1-dependent NDR phosphorylation and promoted a rapid and massive NDR-dependent apoptosis. Overall, our data suggest that Sema6A and Mical1 may represent new potential therapeutic targets in BRAFV600E melanoma. PMID:25576923

  2. Crystal Growth Control

    NASA Technical Reports Server (NTRS)

    Duval, Walter M. B.; Batur, Celal; Bennett, Robert J.

    1997-01-01

    We present an innovative design of a vertical transparent multizone furnace which can operate in the temperature range of 25 C to 750 C and deliver thermal gradients of 2 C/cm to 45 C/cm for the commercial applications to crystal growth. The operation of the eight zone furnace is based on a self-tuning temperature control system with a DC power supply for optimal thermal stability. We show that the desired thermal profile over the entire length of the furnace consists of a functional combination of the fundamental thermal profiles for each individual zone obtained by setting the set-point temperature for that zone. The self-tuning system accounts for the zone to zone thermal interactions. The control system operates such that the thermal profile is maintained under thermal load, thus boundary conditions on crystal growth ampoules can be predetermined prior to crystal growth. Temperature profiles for the growth of crystals via directional solidification, vapor transport techniques, and multiple gradient applications are shown to be easily implemented. The unique feature of its transparency and ease of programming thermal profiles make the furnace useful for scientific and commercial applications for the determination of process parameters to optimize crystal growth conditions.

  3. Automated optogenetic feedback control for precise and robust regulation of gene expression and cell growth

    PubMed Central

    Milias-Argeitis, Andreas; Rullan, Marc; Aoki, Stephanie K.; Buchmann, Peter; Khammash, Mustafa

    2016-01-01

    Dynamic control of gene expression can have far-reaching implications for biotechnological applications and biological discovery. Thanks to the advantages of light, optogenetics has emerged as an ideal technology for this task. Current state-of-the-art methods for optical expression control fail to combine precision with repeatability and cannot withstand changing operating culture conditions. Here, we present a novel fully automatic experimental platform for the robust and precise long-term optogenetic regulation of protein production in liquid Escherichia coli cultures. Using a computer-controlled light-responsive two-component system, we accurately track prescribed dynamic green fluorescent protein expression profiles through the application of feedback control, and show that the system adapts to global perturbations such as nutrient and temperature changes. We demonstrate the efficacy and potential utility of our approach by placing a key metabolic enzyme under optogenetic control, thus enabling dynamic regulation of the culture growth rate with potential applications in bacterial physiology studies and biotechnology. PMID:27562138

  4. Epstein-Barr Virus oncoprotein super-enhancers control B cell growth

    PubMed Central

    Zhou, Hufeng; Schmidt, Stefanie CS; Jiang, Sizun; Willox, Bradford; Bernhardt, Katharina; Liang, Jun; Johannsen, Eric C; Kharchenko, Peter; Gewurz, Benjamin E; Kieff, Elliott; Zhao, Bo

    2015-01-01

    Summary Super-enhancers are clusters of gene-regulatory sites bound by multiple transcription factors that govern cell transcription, development, phenotype, and oncogenesis. By examining Epstein-Barr virus (EBV) transformed lymphoblastoid cell lines (LCLs), we identified four EBV oncoproteins and five EBV-activated NF-κB subunits co-occupying ~1800 enhancer sites. Of these, 187 had markedly higher and broader histone H3K27ac signals characteristic of super-enhancers, and were designated “EBV super-enhancers”. EBV super-enhancer-associated genes included the MYC and BCL2 oncogenes, enabling LCL proliferation and survival. EBV super-enhancers were enriched for B cell transcription factor motifs and had a high co-occupancy of the transcription factors STAT5 and NFAT. EBV super-enhancer-associated genes were more highly expressed than other LCL genes. Disrupting EBV super-enhancers by the bromodomain inhibitor, JQ1 or conditionally inactivating an EBV oncoprotein or NF-κB decreased MYC or BCL2 expression and arrested LCL growth. These findings provide insight into mechanisms of EBV-induced lymphoproliferation and identify potential therapeutic interventions. PMID:25639793

  5. The transcriptional network that controls growth arrest and differentiation in a human myeloid leukemia cell line.

    PubMed

    Suzuki, Harukazu; Forrest, Alistair R R; van Nimwegen, Erik; Daub, Carsten O; Balwierz, Piotr J; Irvine, Katharine M; Lassmann, Timo; Ravasi, Timothy; Hasegawa, Yuki; de Hoon, Michiel J L; Katayama, Shintaro; Schroder, Kate; Carninci, Piero; Tomaru, Yasuhiro; Kanamori-Katayama, Mutsumi; Kubosaki, Atsutaka; Akalin, Altuna; Ando, Yoshinari; Arner, Erik; Asada, Maki; Asahara, Hiroshi; Bailey, Timothy; Bajic, Vladimir B; Bauer, Denis; Beckhouse, Anthony G; Bertin, Nicolas; Björkegren, Johan; Brombacher, Frank; Bulger, Erika; Chalk, Alistair M; Chiba, Joe; Cloonan, Nicole; Dawe, Adam; Dostie, Josee; Engström, Pär G; Essack, Magbubah; Faulkner, Geoffrey J; Fink, J Lynn; Fredman, David; Fujimori, Ko; Furuno, Masaaki; Gojobori, Takashi; Gough, Julian; Grimmond, Sean M; Gustafsson, Mika; Hashimoto, Megumi; Hashimoto, Takehiro; Hatakeyama, Mariko; Heinzel, Susanne; Hide, Winston; Hofmann, Oliver; Hörnquist, Michael; Huminiecki, Lukasz; Ikeo, Kazuho; Imamoto, Naoko; Inoue, Satoshi; Inoue, Yusuke; Ishihara, Ryoko; Iwayanagi, Takao; Jacobsen, Anders; Kaur, Mandeep; Kawaji, Hideya; Kerr, Markus C; Kimura, Ryuichiro; Kimura, Syuhei; Kimura, Yasumasa; Kitano, Hiroaki; Koga, Hisashi; Kojima, Toshio; Kondo, Shinji; Konno, Takeshi; Krogh, Anders; Kruger, Adele; Kumar, Ajit; Lenhard, Boris; Lennartsson, Andreas; Lindow, Morten; Lizio, Marina; Macpherson, Cameron; Maeda, Norihiro; Maher, Christopher A; Maqungo, Monique; Mar, Jessica; Matigian, Nicholas A; Matsuda, Hideo; Mattick, John S; Meier, Stuart; Miyamoto, Sei; Miyamoto-Sato, Etsuko; Nakabayashi, Kazuhiko; Nakachi, Yutaka; Nakano, Mika; Nygaard, Sanne; Okayama, Toshitsugu; Okazaki, Yasushi; Okuda-Yabukami, Haruka; Orlando, Valerio; Otomo, Jun; Pachkov, Mikhail; Petrovsky, Nikolai; Plessy, Charles; Quackenbush, John; Radovanovic, Aleksandar; Rehli, Michael; Saito, Rintaro; Sandelin, Albin; Schmeier, Sebastian; Schönbach, Christian; Schwartz, Ariel S; Semple, Colin A; Sera, Miho; Severin, Jessica; Shirahige, Katsuhiko; Simons, Cas; St Laurent, George; Suzuki, Masanori; Suzuki, Takahiro; Sweet, Matthew J; Taft, Ryan J; Takeda, Shizu; Takenaka, Yoichi; Tan, Kai; Taylor, Martin S; Teasdale, Rohan D; Tegnér, Jesper; Teichmann, Sarah; Valen, Eivind; Wahlestedt, Claes; Waki, Kazunori; Waterhouse, Andrew; Wells, Christine A; Winther, Ole; Wu, Linda; Yamaguchi, Kazumi; Yanagawa, Hiroshi; Yasuda, Jun; Zavolan, Mihaela; Hume, David A; Arakawa, Takahiro; Fukuda, Shiro; Imamura, Kengo; Kai, Chikatoshi; Kaiho, Ai; Kawashima, Tsugumi; Kawazu, Chika; Kitazume, Yayoi; Kojima, Miki; Miura, Hisashi; Murakami, Kayoko; Murata, Mitsuyoshi; Ninomiya, Noriko; Nishiyori, Hiromi; Noma, Shohei; Ogawa, Chihiro; Sano, Takuma; Simon, Christophe; Tagami, Michihira; Takahashi, Yukari; Kawai, Jun; Hayashizaki, Yoshihide

    2009-05-01

    Using deep sequencing (deepCAGE), the FANTOM4 study measured the genome-wide dynamics of transcription-start-site usage in the human monocytic cell line THP-1 throughout a time course of growth arrest and differentiation. Modeling the expression dynamics in terms of predicted cis-regulatory sites, we identified the key transcription regulators, their time-dependent activities and target genes. Systematic siRNA knockdown of 52 transcription factors confirmed the roles of individual factors in the regulatory network. Our results indicate that cellular states are constrained by complex networks involving both positive and negative regulatory interactions among substantial numbers of transcription factors and that no single transcription factor is both necessary and sufficient to drive the differentiation process.

  6. Increasing UV-B induces biphasic leaf cell expansion in Phaseolus vulgaris, suggesting multiple mechanisms for controlling plant growth.

    PubMed

    Barkan, Lenore; Evans, Marc A; Edwards, Gerald E

    2006-01-01

    Leaf expansion, comprising cell division and cell enlargement, is controlled by light quality and quantity. The role of UV-B irradiance on leaf cell enlargement has not been determined. We studied the effect of a wide range of UV-B irradiances on the cell-enlargement-driven expansion of Phaseolus vulgaris L., cv. Contender (bush bean) leaf discs. Our growth method allowed separation of the cell enlargement phase of leaf expansion from the cell division phase. In two series of experiments with different types of UV-B screening filters, the effect of increasing levels of UV-B on the area of excised P. vulgaris leaf discs was investigated. One set of experiments utilized polyester (UV-B-absorbing) and cellulose acetate (UV-B-transmitting) filters. The other set utilized UV-B-absorbing and UV-B-transmitting acrylic filters. Regardless of which type of filter was used for screening, high (above summer solstice) levels of supplemental UV-B inhibited cell enlargement in a linear, dose-dependent manner, resulting in smaller leaf discs than treatment with UV-B-absorbing filters. Conversely, low levels of supplemental UV-B enhanced cell enlargement in a linear, dose-dependent manner, resulting in larger leaf discs than did treatment with UV-B-absorbing filters. The results suggest a biphasic response to UV-B, and that there is an optimum UV-B level that results in maximum leaf expansion by cell enlargement.

  7. Expression of apolipoprotein E by cultured vascular smooth muscle cells is controlled by growth state

    PubMed Central

    1988-01-01

    Rat vascular smooth muscle cells (SMC) in culture synthesize and secrete a approximately 38,000-Mr protein doublet or triplet that, as previously described (Majack and Bornstein. 1984. J. Cell Biol. 99:1688- 1695), rapidly and reversibly accumulates in the SMC culture medium upon addition of heparin. In the present study, we show that this approximately 38,000-Mr heparin-regulated protein is electrophoretically and immunologically identical to apolipoprotein E (apo-E), a major plasma apolipoprotein involved in cholesterol transport. In addition, we show that expression of apo-E by cultured SMC varies according to growth state: while proliferating SMC produced little apo-E and expressed low levels of apo-E mRNA, quiescent SMC produced significantly more apo-E (relative to other proteins) and expressed markedly increased levels of apo-E mRNA. Northern analysis of RNA extracted from aortic tissue revealed that fully differentiated, quiescent SMC contain significant quantities of apo-E mRNA. These data establish aortic SMC as a vascular source for apo-E and suggest new functional roles for this apolipoprotein, possibly unrelated to traditional concepts of lipid metabolism. PMID:2458361

  8. The REVEILLE Clock Genes Inhibit Growth of Juvenile and Adult Plants by Control of Cell Size1[OPEN

    PubMed Central

    Gray, Jennifer A.; Chu, Dalena Nhu

    2017-01-01

    The circadian clock is a complex regulatory network that enhances plant growth and fitness in a constantly changing environment. In Arabidopsis (Arabidopsis thaliana), the clock is composed of numerous regulatory feedback loops in which REVEILLE8 (RVE8) and its homologs RVE4 and RVE6 act in a partially redundant manner to promote clock pace. Here, we report that the remaining members of the RVE8 clade, RVE3 and RVE5, play only minor roles in the regulation of clock function. However, we find that RVE8 clade proteins have unexpected functions in the modulation of light input to the clock and the control of plant growth at multiple stages of development. In seedlings, these proteins repress hypocotyl elongation in a daylength- and sucrose-dependent manner. Strikingly, adult rve4 6 8 and rve3 4 5 6 8 mutants are much larger than wild-type plants, with both increased leaf area and biomass. This size phenotype is associated with a faster growth rate and larger cell size and is not simply due to a delay in the transition to flowering. Gene expression and epistasis analysis reveal that the growth phenotypes of rve mutants are due to the misregulation of PHYTOCHROME INTERACTING FACTOR4 (PIF4) and PIF5 expression. Our results show that even small changes in PIF gene expression caused by the perturbation of clock gene function can have large effects on the growth of adult plants. PMID:28254761

  9. Card9 controls Dectin-1-induced T-cell cytotoxicity and tumor growth in mice.

    PubMed

    Tobias, Haas; Simon, Heidegger; Alexander, Wintges; Michael, Bscheider; Sarah, Bek; Julius C, Fischer; Gabriel, Eisenkolb; Martina, Schmickl; Silvia, Spoerl; Christian, Peschel; Hendrik, Poeck; Jürgen, Ruland

    2017-03-10

    Activation of the C-type lectin receptor Dectin-1 by β-glucans triggers multiple signals within dendritic cells (DCs) that result in activation of innate immunity. While these mechanisms can potently prime CD8(+) cytotoxic T cell (CTL) responses without additional adjuvants, the Dectin-1 effector pathways that control CTL induction remain unclear. Here we demonstrate that Dectin-1-induced CTL cross-priming in mice does not require inflammasome activation but strictly depends on the adapter protein Card9 in vitro. In vivo, Dectin-1-mediated Card9 activation after vaccination drives both expansion and activation of antigen-specific CTLs, resulting in long-lasting CTL responses which are sufficient to protect mice from tumor challenge. This Dectin-1-induced antitumor immune response was independent of natural killer (NK) cell function and completely abrogated in Card9-deficient mice. Thus, our results demonstrate that Dectin-1-triggered Card9 signaling but not inflammasome activation can potently cross-prime antigen specific CTLs, suggesting that this pathway would be a candidate for immunotherapy and vaccine development. This article is protected by copyright. All rights reserved.

  10. Pattern, Growth and Control

    PubMed Central

    Lander, Arthur D.

    2011-01-01

    The view of biology as goal-directed engineering has deep historical roots in developmental biology, a field currently benefitting from an influx of ideas and methods from systems biology. Systems biology draws on non-biological paradigms to explain developmental mechanisms of control, the specific type of regulation that achieves or maintains a desired end. This review highlights some of the current efforts designed to elucidate basic design principles underlying the engineering objectives of robustness, precision, and scaling that are required during developmental control of growth and pattern formation. Examples from vertebrate and invertebrate development are used to illustrate general principles including the value of integral feedback in achieving set-point control; the usefulness of self-organizing behavior; the importance of recognizing and appropriately handling noise; and the No Free Lunch theory. Through the examination of such principles, systems biology offers a functional framework to make sense of the mechanistic complexity of organismal development. PMID:21414486

  11. Control of tissue growth by Yap relies on cell density and F-actin in zebrafish fin regeneration.

    PubMed

    Mateus, Rita; Lourenço, Raquel; Fang, Yi; Brito, Gonçalo; Farinho, Ana; Valério, Fábio; Jacinto, Antonio

    2015-08-15

    Caudal fin regeneration is characterized by a proliferation boost in the mesenchymal blastema that is controlled precisely in time and space. This allows a gradual and robust restoration of original fin size. However, how this is established and regulated is not well understood. Here, we report that Yap, the Hippo pathway effector, is a chief player in this process: functionally manipulating Yap during regeneration dramatically affects cell proliferation and expression of key signaling pathways, impacting regenerative growth. The intracellular location of Yap is tightly associated with different cell densities along the blastema proximal-distal axis, which correlate with alterations in cell morphology, cytoskeleton and cell-cell contacts in a gradient-like manner. Importantly, Yap inactivation occurs in high cell density areas, conditional to F-actin distribution and polymerization. We propose that Yap is essential for fin regeneration and that its function is dependent on mechanical tension, conferred by a balancing act of cell density and cytoskeleton activity. © 2015. Published by The Company of Biologists Ltd.

  12. The Secreted Protease PrtA Controls Cell Growth, Biofilm Formation and Pathogenicity in Xylella fastidiosa

    PubMed Central

    Gouran, Hossein; Gillespie, Hyrum; Nascimento, Rafael; Chakraborty, Sandeep; Zaini, Paulo A.; Jacobson, Aaron; Phinney, Brett S.; Dolan, David; Durbin-Johnson, Blythe P.; Antonova, Elena S.; Lindow, Steven E.; Mellema, Matthew S.; Goulart, Luiz R.; Dandekar, Abhaya M.

    2016-01-01

    Pierce’s disease (PD) is a deadly disease of grapevines caused by the Gram-negative bacterium Xylella fastidiosa. Though disease symptoms were formerly attributed to bacteria blocking the plant xylem, this hypothesis is at best overly simplistic. Recently, we used a proteomic approach to characterize the secretome of X. fastidiosa, both in vitro and in planta, and identified LesA as one of the pathogenicity factors of X. fastidiosa in grapevines that leads to leaf scorching and chlorosis. Herein, we characterize another such factor encoded by PD0956, designated as an antivirulence secreted protease “PrtA” that displays a central role in controlling in vitro cell proliferation, length, motility, biofilm formation, and in planta virulence. The mutant in X. fastidiosa exhibited reduced cell length, hypermotility (and subsequent lack of biofilm formation) and hypervirulence in grapevines. These findings are supported by transcriptomic and proteomic analyses with corresponding plant infection data. Of particular interest, is the hypervirulent response in grapevines observed when X. fastidiosa is disrupted for production of PrtA, and that PD-model tobacco plants transformed to express PrtA exhibited decreased symptoms after infection by X. fastidiosa. PMID:27492542

  13. Microfluidic growth chambers with optical tweezers for full spatial single-cell control and analysis of evolving microbes.

    PubMed

    Probst, Christopher; Grünberger, Alexander; Wiechert, Wolfgang; Kohlheyer, Dietrich

    2013-12-01

    Single-cell analysis in microfluidic systems has opened up new possibilities in biotechnological research enabling us to deal with large eukaryotic cells and even small bacteria. In particular, transient investigations in laminar flow or diffusive environments can be performed to unravel single cell behaviour. Up to now, most systems have been limited with respect to precise cell inoculation and sampling methods. Individual cell selection and manipulations have now been made possible by combining laser tweezers with microfluidic cell cultivation environments specifically tailored for micrometre-sized bacteria. Single cells were optically seeded into various micrometre-sized growth sites arranged in parallel. During cultivation, single-cell elongation, morphology and growth rates were derived from single cells and microcolonies of up to 500 cells. Growth of irradiated bacteria was not impaired by minimizing the exposed laser dosage as confirmed by exceptional growth rates. In fact, Escherichia coli exhibited doubling times of less than 20min. For the first time, a filamentous Escherichia coli WT (MG1655) was safely relocated from its growing microcolony by laser manipulations. The cell was transferred to an empty cultivation spot allowing single-cell growth and morphology investigations. Contrary to previous discussions, the filamentous E. coli exhibited normal cell morphology and division after a few generations. This combination of optical tweezers and single-cell analysis in microfluidics adds a new degree of freedom to microbial single-cell analysis. © 2013.

  14. Encapsulation of basic fibroblast growth factor by polyelectrolyte multilayer microcapsules and its controlled release for enhancing cell proliferation.

    PubMed

    She, Zhen; Wang, Chunxia; Li, Jun; Sukhorukov, Gleb B; Antipina, Maria N

    2012-07-09

    Basic fibroblast growth factor (FGF2) is an important protein for cellular activity and highly vulnerable to environmental conditions. FGF2 protected by heparin and bovine serum albumin was loaded into the microcapsules by a coprecipitation-based layer-by-layer encapsulation method. Low cytotoxic and biodegradable polyelectrolytes dextran sulfate and poly-L-arginine were used for capsule shell assembly. The shell thickness-dependent encapsulation efficiency was measured by enzyme-linked immunosorbent assay. A maximum encapsulation efficiency of 42% could be achieved by microcapsules with a shell thickness of 14 layers. The effects of microcapsule concentration and shell thickness on cytotoxicity, FGF2 release kinetics, and L929 cell proliferation were evaluated in vitro. The advantage of using microcapsules as the carrier for FGF2 controlled release for enhancing L929 cell proliferation was analyzed.

  15. Cell Growth Enhancement

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Exogene Corporation uses advanced technologies to enhance production of bio-processed substances like proteins, antibiotics and amino acids. Among them are genetic modification and a genetic switch. They originated in research for Jet Propulsion Laboratory. Extensive experiments in cell growth through production of hemoglobin to improve oxygen supply to cells were performed. By improving efficiency of oxygen use by cells, major operational expenses can be reduced. Greater product yields result in decreased raw material costs and more efficient use of equipment. A broad range of applications is cited.

  16. Interplay between cell growth and cell cycle in plants.

    PubMed

    Sablowski, Robert; Carnier Dornelas, Marcelo

    2014-06-01

    The growth of organs and whole plants depends on both cell growth and cell-cycle progression, but the interaction between both processes is poorly understood. In plants, the balance between growth and cell-cycle progression requires coordinated regulation of four different processes: macromolecular synthesis (cytoplasmic growth), turgor-driven cell-wall extension, mitotic cycle, and endocycle. Potential feedbacks between these processes include a cell-size checkpoint operating before DNA synthesis and a link between DNA contents and maximum cell size. In addition, key intercellular signals and growth regulatory genes appear to target at the same time cell-cycle and cell-growth functions. For example, auxin, gibberellin, and brassinosteroid all have parallel links to cell-cycle progression (through S-phase Cyclin D-CDK and the anaphase-promoting complex) and cell-wall functions (through cell-wall extensibility or microtubule dynamics). Another intercellular signal mediated by microtubule dynamics is the mechanical stress caused by growth of interconnected cells. Superimposed on developmental controls, sugar signalling through the TOR pathway has recently emerged as a central control point linking cytoplasmic growth, cell-cycle and cell-wall functions. Recent progress in quantitative imaging and computational modelling will facilitate analysis of the multiple interconnections between plant cell growth and cell cycle and ultimately will be required for the predictive manipulation of plant growth.

  17. De novo morphogenesis in L-forms via geometric control of cell growth

    PubMed Central

    Billings, Gabriel; Ouzounov, Nikolay; Ursell, Tristan; Desmarais, Samantha M.; Shaevitz, Joshua; Gitai, Zemer; Huang, Kerwyn Casey

    2015-01-01

    Summary In virtually all bacteria, the cell wall is crucial for mechanical integrity and for determining cell shape. Escherichia coli’s rod-like shape is maintained via the spatiotemporal patterning of cell-wall synthesis by the actin homologue MreB. Here, we transiently inhibited cell-wall synthesis in E. coli to generate cell-wall-deficient, spherical L-forms, and found that they robustly reverted to a rod-like shape within several generations after inhibition cessation. The chemical composition of the cell wall remained essentially unchanged during this process, as indicated by liquid chromatography. Throughout reversion, MreB localized to inwardly curved regions of the cell, and fluorescent cell wall labelling revealed that MreB targets synthesistothose regions. When exposed to the MreB inhibitor A22, reverting cells regrew a cell wall but failed to recover a rod-like shape. Our results suggest that MreB provides the geometric measure that allows E. coli to actively establish and regulate its morphology. PMID:24995493

  18. Carbon nanotube growth density control

    NASA Technical Reports Server (NTRS)

    Delzeit, Lance D. (Inventor); Schipper, John F. (Inventor)

    2010-01-01

    Method and system for combined coarse scale control and fine scale control of growth density of a carbon nanotube (CNT) array on a substrate, using a selected electrical field adjacent to a substrate surface for coarse scale density control (by one or more orders of magnitude) and a selected CNT growth temperature range for fine scale density control (by multiplicative factors of less than an order of magnitude) of CNT growth density. Two spaced apart regions on a substrate may have different CNT growth densities and/or may use different feed gases for CNT growth.

  19. A New Insulin-Like Growth Factor Binding Protein (mac25) and Its Role in Breast Cancer and Cell Growth Control

    DTIC Science & Technology

    1998-09-01

    Kato, M., Sato, H., Tsukada, T., Ikawa, Y., Aizawa, S., and Nagayoshi, M. A. A follistatin -like gene, mac25, may act as a growth suppressor of...T., Ikawa, Y., Aizawa, S., and Nagayoshi, M. A. A follistatin -like gene, mac25, may act as a growth suppressor of osteosarcoma cells., Oncogene. 12

  20. Proteomic analysis of ovarian cancer cells during epithelial-mesenchymal transition (EMT) induced by epidermal growth factor (EGF) reveals mechanisms of cell cycle control.

    PubMed

    Grassi, Mariana Lopes; Palma, Camila de Souza; Thomé, Carolina Hassibe; Lanfredi, Guilherme Pauperio; Poersch, Aline; Faça, Vitor Marcel

    2017-01-16

    Epithelial to mesenchymal transition (EMT) is a well-orchestrated process that culminates with loss of epithelial phenotype and gain of a mesenchymal and migratory phenotype. EMT enhances cancer cell invasiveness and drug resistance, favoring metastasis. Dysregulation of transcription factors, signaling pathways, miRNAs and growth factors including EGF, TGF-beta and HGF can trigger EMT. In ovarian cancer, overexpression of the EGFR family is associated with more aggressive clinical behavior. Here, the ovarian adenocarcinoma cell line Caov-3 was induced to EMT with EGF in order to identify specific mechanisms controlled by this process. Caov-3 cells induced to EMT were thoroughly validated and a combination of subcellular proteome enrichment, GEL-LC-MS/MS and SILAC strategy allowed consistent proteome identification and quantitation. Protein network analysis of differentially expressed proteins highlighted regulation of metabolism and cell cycle. Activation of relevant signaling pathways, such as PI3K/Akt/mTOR and Ras/Erk MAPK, in response to EGF-induced EMT was validated. Also, EMT did not affected the proliferation rate of Caov-3 cells, but led to cell cycle arrest in G1 phase regulated by increased levels of p21Waf1/Cip1, independently of p53. Furthermore, a decrease in G1 and G2 checkpoint proteins was observed, supporting the involvement of EGF-induced EMT in cell cycle control.

  1. Endolysosomal membrane trafficking complexes drive nutrient-dependent TORC1 signaling to control cell growth in Saccharomyces cerevisiae.

    PubMed

    Kingsbury, Joanne M; Sen, Neelam D; Maeda, Tatsuya; Heitman, Joseph; Cardenas, Maria E

    2014-04-01

    The rapamycin-sensitive and endomembrane-associated TORC1 pathway controls cell growth in response to nutrients in eukaryotes. Mutations in class C Vps (Vps-C) complexes are synthetically lethal with tor1 mutations and confer rapamycin hypersensitivity in Saccharomyces cerevisiae, suggesting a role for these complexes in TORC1 signaling. Vps-C complexes are required for vesicular trafficking and fusion and comprise four distinct complexes: HOPS and CORVET and their minor intermediaries (i)-CORVET and i-HOPS. We show that at least one Vps-C complex is required to promote TORC1 activity, with the HOPS complex having the greatest input. The vps-c mutants fail to recover from rapamycin-induced growth arrest and show low levels of TORC1 activity. TORC1 promotes cell growth via Sch9, a p70(S6) kinase ortholog. Constitutively active SCH9 or hyperactive TOR1 alleles restored rapamycin recovery and TORC1 activity of vps-c mutants, supporting a role for the Vps-C complexes upstream of TORC1. The EGO GTPase complex Exit from G0 Complex (EGOC) and its homologous Rag-GTPase complex convey amino acid signals to TORC1 in yeast and mammals, respectively. Expression of the activated EGOC GTPase subunits Gtr1(GTP) and Gtr2(GDP) partially suppressed vps-c mutant rapamycin recovery defects, and this suppression was enhanced by increased amino acid concentrations. Moreover, vps-c mutations disrupted EGOC-TORC1 interactions. TORC1 defects were more severe for vps-c mutants than those observed in EGOC mutants. Taken together, our results support a model in which distinct endolysosomal trafficking Vps-C complexes promote rapamycin-sensitive TORC1 activity via multiple inputs, one of which involves maintenance of amino acid homeostasis that is sensed and transmitted to TORC1 via interactions with EGOC.

  2. Controlled growth of semiconductor nanofilms within TiO₂ nanotubes for nanofilm sensitized solar cells.

    PubMed

    Zheng, Xiaojia; Yu, Dongqi; Xiong, Feng-Qiang; Li, Mingrun; Yang, Zhou; Zhu, Jian; Zhang, Wen-Hua; Li, Can

    2014-04-28

    Anodized TiO2 nanotubes were decorated by II-VI semiconductor nanofilms via atomic layer deposition (ALD) and further employed as photoanodes of semiconductor nanofilm sensitized solar cells (NFSCs) exhibiting superior photovoltaic performance.

  3. SAV742, a Novel AraC-Family Regulator from Streptomyces avermitilis, Controls Avermectin Biosynthesis, Cell Growth and Development

    PubMed Central

    Sun, Di; Zhu, Jianya; Chen, Zhi; Li, Jilun; Wen, Ying

    2016-01-01

    Avermectins are useful anthelmintic antibiotics produced by Streptomyces avermitilis. We demonstrated that a novel AraC-family transcriptional regulator in this species, SAV742, is a global regulator that negatively controls avermectin biosynthesis and cell growth, but positively controls morphological differentiation. Deletion of its gene, sav_742, increased avermectin production and dry cell weight, but caused delayed formation of aerial hyphae and spores. SAV742 directly inhibited avermectin production by repressing transcription of ave structural genes, and also directly regulated its own gene (sav_742) and adjacent gene sig8 (sav_741). The precise SAV742-binding site on its own promoter region was determined by DNase I footprinting assay coupled with site-directed DNA mutagenesis, and 5-nt inverted repeats (GCCGA-n10/n12-TCGGC) were found to be essential for SAV742 binding. Similar 5-nt inverted repeats separated by 3, 10 or 15 nt were found in the promoter regions of target ave genes and sig8. The SAV742 regulon was predicted based on bioinformatic analysis. Twenty-six new SAV742 targets were identified and experimentally confirmed, including genes involved in primary metabolism, secondary metabolism and development. Our findings indicate that SAV742 plays crucial roles in not only avermectin biosynthesis but also coordination of complex physiological processes in S. avermitilis. PMID:27841302

  4. Morphology-controllable ZnO nanostructures: Ethanol-assisted synthesis, growth mechanism and solar cell applications

    NASA Astrophysics Data System (ADS)

    Zhu, Y. F.; Fan, D. H.; Dong, Y. W.; Zhou, G. H.

    2014-10-01

    A very cheap solvent, ethanol, was successfully applied to control ZnO crystal growth for fabricating a series of ZnO composite nanostructures. During the experimental process, a two-step chemical route was adopted. In step-one, ZnO nanowire arrays were grown on fluorine-doped tin oxide coated glass substrate. In step-two, the step-one prepared samples were used as substrates for composite nanostructure deposition. The morphologies of the obtained products were characterized by field emission scanning electron microscopy. The results indicate that the morphologies of the final products can be effectively controlled by changing the water/ethanol ratios in the chemical solution. The obtained ZnO composite nanostructures with various morphologies were successfully employed in dye-sensitized solar cells. The light-to-electricity conversion results show that the composite nanostructures consisting of nanowires and pseudospherical nanostructures enable 80% improvement in solar energy conversion efficiency as compared with the nanowire arrays. These results indicate that the synthesized ZnO composite nanostructures are more suitable for application as photoelectrodes in solar cells.

  5. The bantam microRNA acts through Numb to exert cell growth control and feedback regulation of Notch in tumor-forming stem cells in the Drosophila brain.

    PubMed

    Wu, Yen-Chi; Lee, Kyu-Sun; Song, Yan; Gehrke, Stephan; Lu, Bingwei

    2017-05-01

    Notch (N) signaling is central to the self-renewal of neural stem cells (NSCs) and other tissue stem cells. Its deregulation compromises tissue homeostasis and contributes to tumorigenesis and other diseases. How N regulates stem cell behavior in health and disease is not well understood. Here we show that N regulates bantam (ban) microRNA to impact cell growth, a process key to NSC maintenance and particularly relied upon by tumor-forming cancer stem cells. Notch signaling directly regulates ban expression at the transcriptional level, and ban in turn feedback regulates N activity through negative regulation of the Notch inhibitor Numb. This feedback regulatory mechanism helps maintain the robustness of N signaling activity and NSC fate. Moreover, we show that a Numb-Myc axis mediates the effects of ban on nucleolar and cellular growth independently or downstream of N. Our results highlight intricate transcriptional as well as translational control mechanisms and feedback regulation in the N signaling network, with important implications for NSC biology and cancer biology.

  6. N-Myc knockdown and apigenin treatment controlled growth of malignant neuroblastoma cells having N-Myc amplification

    PubMed Central

    Hossain, Md. Motarab; Banik, Naren L.; Ray, Swapan K.

    2013-01-01

    Malignant neuroblastomas mostly occur in children and are frequently associated with N-Myc amplification. Oncogene amplification, which is selective increase in copy number of the oncogene, provides survival advantages in solid tumors including malignant neuroblastoma. We have decreased expression of N-Myc oncogene using short hairpin RNA (shRNA) plasmid to increase anti-tumor efficacy of the isoflavonoid apigenin (APG) in human malignant neuroblastoma SK-N-DZ and SK-N-BE2 cell lines that harbor N-Myc amplification. N-Myc knockdown induced morphological and biochemical features of neuronal differentiation. Combination of N-Myc knockdown and APG most effectively induced morphological and biochemical features of apoptotic death. This combination therapy also prevented cell migration and decreased N-Myc driven survival, angiogenic, and invasive factors. Collectively, N-Myc knockdown and APG treatment is a promising strategy for controlling the growth of human malignant neuroblastoma cell lines that harbor N-Myc amplification. PMID:23941992

  7. A Bilayer Construct Controls Adipose-Derived Stem Cell Differentiation into Endothelial Cells and Pericytes without Growth Factor Stimulation

    DTIC Science & Technology

    2011-01-01

    dermal matrix. Our intent is that such a construct could be utilized following large-surface-area burn wounds that require extensive skin grafting and that...This challenge, in combination with the time required to grow significant numbers of autologous cells, has limited the clinical utility of the...on stem cells, such as epidermal stem cells, dermal stem cells, and mesenchymal stem cells (MSC) from bone marrow, may provide technologies for the

  8. Migration of oligodendrocyte progenitor cells is controlled by transforming growth factor β family proteins during corticogenesis.

    PubMed

    Choe, Youngshik; Huynh, Trung; Pleasure, Samuel J

    2014-11-05

    During embryonic development oligodendrocyte precursor cells (OPCs) are generated first in the ventral forebrain and migrate dorsally to occupy the cortex. The molecular cues that guide this migratory route are currently completely unknown. Here, we show that bone morphogenetic protein-4 (Bmp4), Bmp7, and Tgfβ1 produced by the meninges and pericytes repelled ventral OPCs into the cortex at mouse embryonic stages. Ectopic activation of Bmp or Tgfβ1 signaling before the entrance of OPCs into the cortex hindered OPC migration into the cortical areas. OPCs without Smad4 signaling molecules also failed to migrate into the cortex efficiently and formed heterotopia in ventral areas. OPC migration into the cortex was also dramatically reduced by conditional inhibition of Tgfβ1 or Bmp expression from mesenchymal cells. The data suggest that mesenchymal Tgfβ family proteins promote migration of ventral OPCs into the cortex during corticogenesis.

  9. High-density polymer microarrays: identifying synthetic polymers that control human embryonic stem cell growth.

    PubMed

    Hansen, Anne; Mjoseng, Heidi K; Zhang, Rong; Kalloudis, Michail; Koutsos, Vasileios; de Sousa, Paul A; Bradley, Mark

    2014-06-01

    The fabrication of high-density polymer microarray is described, allowing the simultaneous and efficient evaluation of more than 7000 different polymers in a single-cellular-based screen. These high-density polymer arrays are applied in the search for synthetic substrates for hESCs culture. Up-scaling of the identified hit polymers enables long-term cellular cultivation and promoted successful stem-cell maintenance.

  10. Genetic dissection of cardiac growth control pathways

    NASA Technical Reports Server (NTRS)

    MacLellan, W. R.; Schneider, M. D.

    2000-01-01

    Cardiac muscle cells exhibit two related but distinct modes of growth that are highly regulated during development and disease. Cardiac myocytes rapidly proliferate during fetal life but exit the cell cycle irreversibly soon after birth, following which the predominant form of growth shifts from hyperplastic to hypertrophic. Much research has focused on identifying the candidate mitogens, hypertrophic agonists, and signaling pathways that mediate these processes in isolated cells. What drives the proliferative growth of embryonic myocardium in vivo and the mechanisms by which adult cardiac myocytes hypertrophy in vivo are less clear. Efforts to answer these questions have benefited from rapid progress made in techniques to manipulate the murine genome. Complementary technologies for gain- and loss-of-function now permit a mutational analysis of these growth control pathways in vivo in the intact heart. These studies have confirmed the importance of suspected pathways, have implicated unexpected pathways as well, and have led to new paradigms for the control of cardiac growth.

  11. Genetic dissection of cardiac growth control pathways

    NASA Technical Reports Server (NTRS)

    MacLellan, W. R.; Schneider, M. D.

    2000-01-01

    Cardiac muscle cells exhibit two related but distinct modes of growth that are highly regulated during development and disease. Cardiac myocytes rapidly proliferate during fetal life but exit the cell cycle irreversibly soon after birth, following which the predominant form of growth shifts from hyperplastic to hypertrophic. Much research has focused on identifying the candidate mitogens, hypertrophic agonists, and signaling pathways that mediate these processes in isolated cells. What drives the proliferative growth of embryonic myocardium in vivo and the mechanisms by which adult cardiac myocytes hypertrophy in vivo are less clear. Efforts to answer these questions have benefited from rapid progress made in techniques to manipulate the murine genome. Complementary technologies for gain- and loss-of-function now permit a mutational analysis of these growth control pathways in vivo in the intact heart. These studies have confirmed the importance of suspected pathways, have implicated unexpected pathways as well, and have led to new paradigms for the control of cardiac growth.

  12. Combined toll-like receptor 3/7/9 deficiency on host cells results in T-cell-dependent control of tumour growth

    PubMed Central

    Klein, Johanna C.; Moses, Katrin; Zelinskyy, Gennadiy; Sody, Simon; Buer, Jan; Lang, Stephan; Helfrich, Iris; Dittmer, Ulf; Kirschning, Carsten J.; Brandau, Sven

    2017-01-01

    Toll-like receptors (TLRs) are located either on the cell surface or intracellularly in endosomes and their activation normally contributes to the induction of protective immune responses. However, in cancer their activation by endogenous ligands can modulate tumour progression. It is currently unknown how endosomal TLRs regulate endogenous anti-tumour immunity. Here we show that TLR3, 7 and 9 deficiencies on host cells, after initial tumour growth, result in complete tumour regression and induction of anti-tumour immunity. Tumour regression requires the combined absence of all three receptors, is dependent on both CD4 and CD8 T cells and protects the mice from subsequent tumour challenge. While tumours in control mice are infiltrated by higher numbers of regulatory T cells, tumour regression in TLR-deficient mice is paralleled by altered vascular structure and strongly induced influx of cytotoxic and cytokine-producing effector T cells. Thus, endosomal TLRs may represent a molecular link between the inflamed tumour cell phenotype, anti-tumour immunity and the regulation of T-cell activation. PMID:28300057

  13. Hormonal Control of Fetal Growth.

    ERIC Educational Resources Information Center

    Cooke, Paul S.; Nicoll, Charles S.

    1983-01-01

    Summarizes recent research on hormonal control of fetal growth, presenting data obtained using a new method for studying the area. Effects of endocrine ablations and congenital deficiencies, studies of hormone/receptor levels, in-vitro techniques, hormones implicated in promoting fetal growth, problems with existing methodologies, and growth of…

  14. Hormonal Control of Fetal Growth.

    ERIC Educational Resources Information Center

    Cooke, Paul S.; Nicoll, Charles S.

    1983-01-01

    Summarizes recent research on hormonal control of fetal growth, presenting data obtained using a new method for studying the area. Effects of endocrine ablations and congenital deficiencies, studies of hormone/receptor levels, in-vitro techniques, hormones implicated in promoting fetal growth, problems with existing methodologies, and growth of…

  15. Temporal Control of Transforming Growth Factor (TGF) - Betal Expression on Mammary Cell Multistep Transformation

    DTIC Science & Technology

    2001-10-01

    acting via Erk MAP kinases, causes phosphorylation at sites in the 1243-1252. linker region of Smad2 and Smad3 , which, in turn, inhibit Smad accumula...been observed in cell lines or xenografts de- addition to Smad2 and Smad4, Smad3 is an- rived from human colon carcinomas (28, 31). other member of the...pathogenesis of col- though mutations in the Smad3 gene have not orectal cancer between mice and humans. Alter- yet been detected in human colorectal cancer

  16. Interferon response factor 3 is crucial to poly-I:C induced NK cell activity and control of B16 melanoma growth.

    PubMed

    Moore, Tyler C; Kumm, Phyllis M; Brown, Deborah M; Petro, Thomas M

    2014-04-28

    Interferon Response Factor 3 (IRF3) induces several NK-cell activating factors, is activated by poly-I:C, an experimental cancer therapeutic, but is suppressed during many viral infections. IRF3 Knockout (KO) mice exhibited enhanced B16 melanoma growth, impaired intratumoral NK cell infiltration, but not an impaired poly-I:C therapeutic effect due to direct suppression of B16 growth. IRF3 was responsible for poly-I:C decrease in TIM-3 expression by intratumoral dendritic cells, induction of NK-cell Granzyme B and IFN-γ, and induction of macrophage IL-12, IL-15, IL-6, and IRF3-dependent NK-activating molecule (INAM). Thus, IRF3 is a key factor controlling melanoma growth through NK-cell activities, especially during poly-I:C therapy.

  17. Chemical Control of Plant Growth.

    ERIC Educational Resources Information Center

    Agricultural Research Center (USDA), Beltsville, MD.

    Seven experiments are presented in this Science Study Aid to help students investigate the control of plant growth with chemicals. Plant growth regulators, weed control, and chemical pruning are the topics studied in the experiments which are based on investigations that have been and are being conducted at the U. S. Agricultural Research Center,…

  18. Inferring Growth Control Mechanisms in Growing Multi-cellular Spheroids of NSCLC Cells from Spatial-Temporal Image Data.

    PubMed

    Jagiella, Nick; Müller, Benedikt; Müller, Margareta; Vignon-Clementel, Irene E; Drasdo, Dirk

    2016-02-01

    We develop a quantitative single cell-based mathematical model for multi-cellular tumor spheroids (MCTS) of SK-MES-1 cells, a non-small cell lung cancer (NSCLC) cell line, growing under various nutrient conditions: we confront the simulations performed with this model with data on the growth kinetics and spatial labeling patterns for cell proliferation, extracellular matrix (ECM), cell distribution and cell death. We start with a simple model capturing part of the experimental observations. We then show, by performing a sensitivity analysis at each development stage of the model that its complexity needs to be stepwise increased to account for further experimental growth conditions. We thus ultimately arrive at a model that mimics the MCTS growth under multiple conditions to a great extent. Interestingly, the final model, is a minimal model capable of explaining all data simultaneously in the sense, that the number of mechanisms it contains is sufficient to explain the data and missing out any of its mechanisms did not permit fit between all data and the model within physiological parameter ranges. Nevertheless, compared to earlier models it is quite complex i.e., it includes a wide range of mechanisms discussed in biological literature. In this model, the cells lacking oxygen switch from aerobe to anaerobe glycolysis and produce lactate. Too high concentrations of lactate or too low concentrations of ATP promote cell death. Only if the extracellular matrix density overcomes a certain threshold, cells are able to enter the cell cycle. Dying cells produce a diffusive growth inhibitor. Missing out the spatial information would not permit to infer the mechanisms at work. Our findings suggest that this iterative data integration together with intermediate model sensitivity analysis at each model development stage, provide a promising strategy to infer predictive yet minimal (in the above sense) quantitative models of tumor growth, as prospectively of other tissue

  19. Inferring Growth Control Mechanisms in Growing Multi-cellular Spheroids of NSCLC Cells from Spatial-Temporal Image Data

    PubMed Central

    Müller, Margareta; Vignon-Clementel, Irene E.; Drasdo, Dirk

    2016-01-01

    We develop a quantitative single cell-based mathematical model for multi-cellular tumor spheroids (MCTS) of SK-MES-1 cells, a non-small cell lung cancer (NSCLC) cell line, growing under various nutrient conditions: we confront the simulations performed with this model with data on the growth kinetics and spatial labeling patterns for cell proliferation, extracellular matrix (ECM), cell distribution and cell death. We start with a simple model capturing part of the experimental observations. We then show, by performing a sensitivity analysis at each development stage of the model that its complexity needs to be stepwise increased to account for further experimental growth conditions. We thus ultimately arrive at a model that mimics the MCTS growth under multiple conditions to a great extent. Interestingly, the final model, is a minimal model capable of explaining all data simultaneously in the sense, that the number of mechanisms it contains is sufficient to explain the data and missing out any of its mechanisms did not permit fit between all data and the model within physiological parameter ranges. Nevertheless, compared to earlier models it is quite complex i.e., it includes a wide range of mechanisms discussed in biological literature. In this model, the cells lacking oxygen switch from aerobe to anaerobe glycolysis and produce lactate. Too high concentrations of lactate or too low concentrations of ATP promote cell death. Only if the extracellular matrix density overcomes a certain threshold, cells are able to enter the cell cycle. Dying cells produce a diffusive growth inhibitor. Missing out the spatial information would not permit to infer the mechanisms at work. Our findings suggest that this iterative data integration together with intermediate model sensitivity analysis at each model development stage, provide a promising strategy to infer predictive yet minimal (in the above sense) quantitative models of tumor growth, as prospectively of other tissue

  20. Coadministration of adipose-derived stem cells and control-released basic fibroblast growth factor facilitates angiogenesis in a murine ischemic hind limb model.

    PubMed

    Horikoshi-Ishihara, Hisako; Tobita, Morikuni; Tajima, Satoshi; Tanaka, Rica; Oshita, Takashi; Tabata, Yasuhiko; Mizuno, Hiroshi

    2016-12-01

    Adipose-derived stem cells (ASCs) have angiogenic potential owing to their differentiation into endothelial cells and their release of angiogenic growth factors to elicit paracrine effects. In addition, control-released basic fibroblast growth factor (bFGF) sustained with a gelatin hydrogel also supports effective angiogenesis. We sought to determine if coadministration of ASCs and control-released bFGF into murine ischemic limbs facilitates angiogenesis. Levels of growth factors in the conditioned media of ASCs cultured with or without control-released bFGF were measured by enzyme-linked immunosorbent assays. A murine ischemic hind limb model was generated and intramuscularly injected with the following: gelatin hydrogel (group 1), a high number of ASCs (group 2), control-released bFGF (group 3), a small number of ASCs and control-released bFGF (group 4), and a high number of ASCs and control-released bFGF (group 5). Macroscopic and microscopic vascular changes were evaluated until day 7 by laser Doppler perfusion imaging and histologic analyses, respectively. Secretion of hepatocyte growth factor, vascular endothelial growth factor, and transforming growth factor-β1 was enhanced by control-released bFGF. Vascular improvement was achieved in groups 4 and 5 according to laser Doppler perfusion imaging. Hematoxylin and eosin staining and CD31 immunohistochemical staining demonstrated an increase in the vascular density, vessel diameter, and thickness of vessel walls in groups 4 and 5. Cells positively stained for CD146, α-smooth muscle actin, and transforming growth factor-β1 were observed around vessel walls in groups 4 and 5. These findings suggest that coadministration of ASCs and control-released bFGF facilitates angiogenesis in terms of vessel maturation in a murine ischemic hind limb model. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  1. Controllable thin film crystal growth of a novel squaraine molecule in organic solar cells

    NASA Astrophysics Data System (ADS)

    Conrad, Brad; Spencer, Susan; Bougher, Cortney; Brown, Jesse; Kelley, Kyle; Heaphy, Patrick; Murcia, Victor; Gallivan, Cameron; Monfette, Amber; Andersen, John; Cody, Jeremy; Coffey, Tonya; Collison, Christopher

    2014-03-01

    We will discuss the formation, structures, and properties of squarine and squarine-PCBM blend thin-films using Atomic Force Microscopy, electrical characterization, UV-VIS-NIR, and Thin-film Xray Diffraction. Film properties are inferred from spectroscopic measurements and are correlated with crystallinity as determined by TFXRD and AFM. A comprehensive explanation of DiPSQ(OH)2 structures is provided and related to measured efficiencies up to 4.3. By controlling the blend ratio and other fabrication conditions, crystalline regions of higher mobility can be developed so as to make significant gains in power conversion efficiency, necessary to achieve long term goals for commercially viable NIR-active OPV devices. AppState Office of Student Research; Synthesis by Cody group. BRC thanks ORAU Junior Faculty Enhancement Award. SDS, CPG and AM thank DOE Award number DE-FG36-08GO88110. CJC and JAC thank NSF award number CBET-1236372.

  2. Human pituitary and placental hormones control human insulin-like growth factor II secretion in human granulosa cells

    SciTech Connect

    Ramasharma, K.; Li, C.H.

    1987-05-01

    Human granulosa cells cultured with calf serum actively proliferated for 18-20 generations and secreted progesterone into the medium; progesterone levels appeared to decline with increase in generation number. Cells cultured under serum-free conditions secreted significant amounts of progesterone and insulin-like growth factor II (IGF-II). The progesterone secretion was enhanced by the addition of human follitropin, lutropin, and chorionic gonadotropin but not by growth hormone. These cells, when challenged to varying concentrations of human growth hormone, human chorionic somatomammotropin, human prolactin, chorionic gonadotropin, follitropin, and lutropin, secreted IGF-II into the medium as measured by specific IGF-II RIA. Among these human hormones, chorionic gonadotropin, follitropin, and lutropin were most effective in inducing IGF-II secretion from these cells. When synthetic lutropin-releasing hormone and ..cap alpha..-inhibin-92 were tested, only lutropin-releasing hormone was effective in releasing IGF-II. The results described suggest that cultured human granulosa cells can proliferate and actively secrete progesterone and IGF-II into the medium. IGF-II production in human granulosa cells was influenced by a multi-hormonal complex including human growth hormone, human chorionic somatomammotropin, and prolactin.

  3. Avidity-controlled hydrogels for injectable co-delivery of induced pluripotent stem cell-derived endothelial cells and growth factors.

    PubMed

    Mulyasasmita, Widya; Cai, Lei; Dewi, Ruby E; Jha, Arshi; Ullmann, Sabrina D; Luong, Richard H; Huang, Ngan F; Heilshorn, Sarah C

    2014-10-10

    To translate recent advances in induced pluripotent stem cell biology to clinical regenerative medicine therapies, new strategies to control the co-delivery of cells and growth factors are needed. Building on our previous work designing Mixing-Induced Two-Component Hydrogels (MITCHs) from engineered proteins, here we develop protein-polyethylene glycol (PEG) hybrid hydrogels, MITCH-PEG, which form physical gels upon mixing for cell and growth factor co-delivery. MITCH-PEG is a mixture of C7, which is a linear, engineered protein containing seven repeats of the CC43 WW peptide domain (C), and 8-arm star-shaped PEG conjugated with either one or two repeats of a proline-rich peptide to each arm (P1 or P2, respectively). Both 20kDa and 40kDa star-shaped PEG variants were investigated, and all four PEG-peptide variants were able to undergo a sol-gel phase transition when mixed with the linear C7 protein at constant physiological conditions due to noncovalent hetero-dimerization between the C and P domains. Due to the dynamic nature of the C-P physical crosslinks, all four gels were observed to be reversibly shear-thinning and self-healing. The P2 variants exhibited higher storage moduli than the P1 variants, demonstrating the ability to tune the hydrogel bulk properties through a biomimetic peptide-avidity strategy. The 20kDa PEG variants exhibited slower release of encapsulated vascular endothelial growth factor (VEGF), due to a decrease in hydrogel mesh size relative to the 40kDa variants. Human induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs) adopted a well-spread morphology within three-dimensional MITCH-PEG cultures, and MITCH-PEG provided significant protection from cell damage during ejection through a fine-gauge syringe needle. In a mouse hindlimb ischemia model of peripheral arterial disease, MITCH-PEG co-delivery of hiPSC-ECs and VEGF was found to reduce inflammation and promote muscle tissue regeneration compared to a saline control.

  4. Avidity-controlled hydrogels for injectable co-delivery of induced pluripotent stem cell-derived endothelial cells and growth factors

    PubMed Central

    Mulyasasmita, Widya; Cai, Lei; Dewi, Ruby E.; Jha, Arshi; Ullmann, Sabrina D.; Luong, Richard H.; Huang, Ngan F.; Heilshorn, Sarah C.

    2015-01-01

    To translate recent advances in induced pluripotent stem cell biology to clinical regenerative medicine therapies, new strategies to control the co-delivery of cells and growth factors are needed. Building on our previous work designing Mixing-Induced Two-Component Hydrogels (MITCH) from engineered proteins, here we develop protein-polyethylene glycol (PEG) hybrid hydrogels, MITCH-PEG, which form physical gels upon mixing for cell and growth factor co-delivery. MITCH-PEG is a mixture of C7, which is a linear, engineered protein containing seven repeats of the CC43 WW peptide domain (C), and 8-arm star-shaped PEG conjugated with either one or two repeats of a proline-rich peptide to each arm (P1 or P2, respectively). Both 20 kDa and 40 kDa star-shaped PEG were investigated, and all four PEG variants were able to undergo a sol-gel phase transition when mixed with the linear C7 protein at constant physiological conditions due to noncovalent hetero-dimerization between the C and P domains. Due to the dynamic nature of the C-P physical crosslinks, all four gels were observed to be reversibly shear-thinning and self-healing. The P2 variants exhibited higher storage moduli than the P1 variants, demonstrating the ability to tune the hydrogel bulk properties through a biomimetic peptide-avidity strategy. The 20 kDa PEG variants exhibited slower release of encapsulated vascular endothelial growth factor (VEGF), due to a decrease in hydrogel mesh size relative to the 40 kDa variants. Human induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs) adopted a well-spread morphology within three-dimensional MITCH-PEG cultures, and MITCH-PEG provided significant protection from cell damage during ejection through a fine-gauge syringe needle. In a mouse hindlimb ischemia model of peripheral arterial disease, MITCH-PEG co-delivery of hiPSC-ECs and VEGF was found to reduce inflammation and promote muscle tissue regeneration compared to a saline control. PMID:24848744

  5. NUPR1, a new target in liver cancer: implication in controlling cell growth, migration, invasion and sorafenib resistance.

    PubMed

    Emma, M R; Iovanna, J L; Bachvarov, D; Puleio, R; Loria, G R; Augello, G; Candido, S; Libra, M; Gulino, A; Cancila, V; McCubrey, J A; Montalto, G; Cervello, M

    2016-06-23

    Sorafenib, an oral multikinase inhibitor, is the only approved agent for the treatment of advanced hepatocellular carcinoma (HCC). However, its benefits are modest, and as its mechanisms of action remain elusive, a better understanding of its anticancer effects is needed. Based on our previous study results, we investigated here the implication of the nuclear protein 1 (NUPR1) in HCC and its role in sorafenib treatment. NUPR1 is a stress-inducible protein that is overexpressed in various malignancies, but its role in HCC is not yet fully understood. We found that NUPR1 expression was significantly higher in primary human HCC samples than in the normal liver. Knockdown of NUPR1 significantly increased cell sensitivity to sorafenib and inhibited the cell growth, migration and invasion of HCC cells, both in vitro and in vivo. Moreover, NUPR1 silencing influenced the expression of RELB and IER3 genes. Unsurprisingly, RELB and IER3 knockdown also inhibited HCC cell viability, growth and migration. Using gene expression profiling of HCC cells following stable NUPR1 knockdown, we found that genes functionally involved in cell death and survival, cellular response to therapies, lipid metabolism, cell growth and proliferation, molecular transport and cellular movement were mostly suppressed. Network analysis of dynamic gene expression identified NF-κB and ERK as downregulated gene nodes, and several HCC-related oncogenes were also suppressed. We identified Runt-related transcription factor 2 (RUNX2) gene as a NUPR1-regulated gene and demonstrated that RUNX2 gene silencing inhibits HCC cell viability, growth, migration and increased cell sensitivity to sorafenib. We propose that the NUPR1/RELB/IER3/RUNX2 pathway has a pivotal role in hepatocarcinogenesis. The identification of the NUPR1/RELB/IER3/RUNX2 pathway as a potential therapeutic target may contribute to the development of new treatment strategies for HCC management.

  6. NUPR1, a new target in liver cancer: implication in controlling cell growth, migration, invasion and sorafenib resistance

    PubMed Central

    Emma, M R; Iovanna, J L; Bachvarov, D; Puleio, R; Loria, G R; Augello, G; Candido, S; Libra, M; Gulino, A; Cancila, V; McCubrey, J A; Montalto, G; Cervello, M

    2016-01-01

    Sorafenib, an oral multikinase inhibitor, is the only approved agent for the treatment of advanced hepatocellular carcinoma (HCC). However, its benefits are modest, and as its mechanisms of action remain elusive, a better understanding of its anticancer effects is needed. Based on our previous study results, we investigated here the implication of the nuclear protein 1 (NUPR1) in HCC and its role in sorafenib treatment. NUPR1 is a stress-inducible protein that is overexpressed in various malignancies, but its role in HCC is not yet fully understood. We found that NUPR1 expression was significantly higher in primary human HCC samples than in the normal liver. Knockdown of NUPR1 significantly increased cell sensitivity to sorafenib and inhibited the cell growth, migration and invasion of HCC cells, both in vitro and in vivo. Moreover, NUPR1 silencing influenced the expression of RELB and IER3 genes. Unsurprisingly, RELB and IER3 knockdown also inhibited HCC cell viability, growth and migration. Using gene expression profiling of HCC cells following stable NUPR1 knockdown, we found that genes functionally involved in cell death and survival, cellular response to therapies, lipid metabolism, cell growth and proliferation, molecular transport and cellular movement were mostly suppressed. Network analysis of dynamic gene expression identified NF-κB and ERK as downregulated gene nodes, and several HCC-related oncogenes were also suppressed. We identified Runt-related transcription factor 2 (RUNX2) gene as a NUPR1-regulated gene and demonstrated that RUNX2 gene silencing inhibits HCC cell viability, growth, migration and increased cell sensitivity to sorafenib. We propose that the NUPR1/RELB/IER3/RUNX2 pathway has a pivotal role in hepatocarcinogenesis. The identification of the NUPR1/RELB/IER3/RUNX2 pathway as a potential therapeutic target may contribute to the development of new treatment strategies for HCC management. PMID:27336713

  7. Butyrate metabolism upstream and downstream acetyl-CoA synthesis and growth control of human colon carcinoma cells.

    PubMed

    Leschelle, X; Delpal, S; Goubern, M; Blottière, H M; Blachier, F

    2000-11-01

    Butyrate is a short chain fatty acid (SCFA) produced by bacterial fermentation of dietary fibers in the colon lumen which severely affects the proliferation of colon cancer cells in in vitro experiments. Although butyrate is able to interfere with numerous cellular targets including cell cycle regulator expression, little is known about butyrate metabolism and its possible involvement in its effect upon colon carcinoma cell growth. In this study, we found that HT-29 Glc-/+ cells strongly accumulated and oxidized sodium butyrate without producing ketone bodies, nor modifying oxygen consumption nor mitochondrial ATP synthesis. HT-29 cells accumulated and oxidized sodium acetate at a higher level than butyrate. However, sodium butyrate, but not sodium acetate, reduced cell growth and increased the expression of the cell cycle effector cyclin D3 and the inhibitor of the G1/S cdk-cyclin complexes p21/WAF1/Cip1, demonstrating that butyrate metabolism downstream of acetyl-CoA synthesis is not required for the growth-restraining effect of this SCFA. Furthermore, HT-29 cells modestly incorporated the 14C-labelled carbon from sodium butyrate into cellular triacylglycerols and phospholipids. This incorporation was greatly increased when D-glucose was present in the incubation medium, corresponding to the capacity of hexose to circulate in the pentose phosphate pathway allowing NADPH synthesis required for lipogenesis. Interestingly, when HT-29 cells were cultured in the presence of sodium butyrate, their capacity to incorporate 14C-labelled sodium butyrate into triacylglycerols and phospholipids was increased more than twofold. In such experimental conditions, HT-29 cells when observed under an electronic microscope, were found to be characterized by an accumulation of lipid droplets in the cytosol. Our data strongly suggest that butyrate acts upon colon carcinoma cells upstream of acetyl-CoA synthesis. In contrast, the metabolism downstream of acetyl-CoA [i.e. oxidation in

  8. Dynamically controlled crystal growth system

    NASA Technical Reports Server (NTRS)

    Bray, Terry L. (Inventor); Kim, Larry J. (Inventor); Harrington, Michael (Inventor); DeLucas, Lawrence J. (Inventor)

    2002-01-01

    Crystal growth can be initiated and controlled by dynamically controlled vapor diffusion or temperature change. In one aspect, the present invention uses a precisely controlled vapor diffusion approach to monitor and control protein crystal growth. The system utilizes a humidity sensor and various interfaces under computer control to effect virtually any evaporation rate from a number of different growth solutions simultaneously by means of an evaporative gas flow. A static laser light scattering sensor can be used to detect aggregation events and trigger a change in the evaporation rate for a growth solution. A control/follower configuration can be used to actively monitor one chamber and accurately control replicate chambers relative to the control chamber. In a second aspect, the invention exploits the varying solubility of proteins versus temperature to control the growth of protein crystals. This system contains miniature thermoelectric devices under microcomputer control that change temperature as needed to grow crystals of a given protein. Complex temperature ramps are possible using this approach. A static laser light scattering probe also can be used in this system as a non-invasive probe for detection of aggregation events. The automated dynamic control system provides systematic and predictable responses with regard to crystal size. These systems can be used for microgravity crystallization projects, for example in a space shuttle, and for crystallization work under terrestial conditions. The present invention is particularly useful for macromolecular crystallization, e.g. for proteins, polypeptides, nucleic acids, viruses and virus particles.

  9. Pleomorphic carcinomas of the lung show a selective distribution of gene products involved in cell differentiation, cell cycle control, tumor growth, and tumor cell motility: a clinicopathologic and immunohistochemical study of 31 cases.

    PubMed

    Pelosi, Giuseppe; Fraggetta, Filippo; Nappi, Oscar; Pastorino, Ugo; Maisonneuve, Patrick; Pasini, Felice; Iannucci, Antonio; Solli, Piergiorgio; Musavinasab, Hossein S; De Manzoni, Giovanni; Terzi, Alberto; Viale, Giuseppe

    2003-09-01

    We investigated 31 cases of pleomorphic carcinomas of the lung, with a double component of neoplastic epithelial cells and of spindle and/or giant cells. To correlate the morphologic diversity of these two cell components with their immunophenotype, we evaluated the expression of several gene products involved in cell differentiation (cytokeratins, epithelial membrane antigen, carcinoembryonic antigen, vimentin, S-100 protein, smooth muscle actin, desmin), cell cycle control and apoptosis (p53, p21Waf1, p27Kip1, FHIT), tumor growth (proliferative fraction, assessed by Ki-67 antigen, and microvascular density, assessed by CD34 immunostaining), and tumor cell motility (fascin). We found the epithelial component to be significantly more immunoreactive for cytokeratins, epithelial membrane antigen, carcinoembryonic antigen, cell cycle inhibitors p21Waf1, p27Kip1 and tumor suppressor gene FHIT, whereas the sarcomatoid component, independent of tumor stage and size, was more immunoreactive for vimentin, fascin, and microvascular density. Accordingly, we suggest a model of tumorigenesis whereby the mesenchymal phenotype of pleomorphic cells is likely induced by the selective activation and segregation of several molecules involved in cell differentiation, cell cycle control, and tumor cell growth and motility. Whether pleomorphic carcinomas of the lung are tumors with a dismal prognosis still remains an unsettled issue. In our series, however, stage I pleomorphic carcinomas have the same clinical behavior as ordinary non-small cell lung cancer, and only a high proliferative index (Ki-67 labeling index >35%) is associated with a worse prognosis in these tumors.

  10. Rapid, controllable growth of silver nanostructured surface-enhanced Raman scattering substrates for red blood cell detection

    NASA Astrophysics Data System (ADS)

    Zhang, Shu; Tian, Xueli; Yin, Jun; Liu, Yu; Dong, Zhanmin; Sun, Jia-Lin; Ma, Wanyun

    2016-04-01

    Silver nanostructured films suitable for use as surface-enhanced Raman scattering (SERS) substrates are prepared in just 2 hours by the solid-state ionics method. By changing the intensity of the external direct current, we can readily control the surface morphology and growth rate of the silver nanostructured films. A detailed investigation of the surface enhancement of the silver nanostructured films using Rhodamine 6G (R6G) as a molecular probe revealed that the enhancement factor of the films was up to 1011. We used the silver nanostructured films as substrates in SERS detection of human red blood cells (RBCs). The SERS spectra of RBCs on the silver nanostructured film could be clearly detected at a laser power of just 0.05 mW. Comparison of the SERS spectra of RBCs obtained from younger and older donors showed that the SERS spectra depended on donor age. A greater proportion of the haemoglobin in the RBCs of older donors was in the deoxygenated state than that of the younger donors. This implies that haemoglobin of older people has lower oxygen-carrying capacity than that of younger people. Overall, the fabricated silver substrates show promise in biomedical SERS spectral detection.

  11. New insights into the functional roles of CrRLKs in the control of plant cell growth and development.

    PubMed

    Nibau, Candida; Cheung, Alice Y

    2011-05-01

    Receptor-like kinases (RLKs) are a family of transmembrane proteins with a variable ligand-binding extracellular domain and a cytoplasmic kinase domain. In Arabidopsis, there are ~600 RLKs believed to have diverse functions during plant growth, development and interactions with the environment. Based on the variable extracellular domain, RLKs can be classified into different subfamilies. The CrRLK subfamily contains 17 members in Arabidopsis and characterization of some of its members suggests a role for these proteins in the regulation of growth and reproduction. The present review focuses on the roles of CrRLKs in the regulation of polarized growth with emphasis on the newly identified signal transduction pathways activated downstream of CrRLKs. A picture is emerging where CrRLKs are part of a conserved signal transduction cascade important for growth maintenance in different cell types.

  12. Effects of epidermal growth factor and dimethylhydrazine on crypt size, cell proliferation, and crypt fission in the rat colon. Cell proliferation and crypt fission are controlled independently.

    PubMed Central

    Park, H. S.; Goodlad, R. A.; Ahnen, D. J.; Winnett, A.; Sasieni, P.; Lee, C. Y.; Wright, N. A.

    1997-01-01

    Crypt fission is now established as an important mechanism of intestinal growth and regeneration. It has been proposed that increased crypt size is the stimulus for crypt fission, because crypts preparing for fission are generally larger. Consequently, we investigated the effects of epidermal growth factor (EGF) and dimethylhydrazine, which are both known to stimulate crypt cell proliferation, on crypt fission in the rat intestine. We also examined whether the effects of EGF on both proliferation and crypt fission are modified by the pretreatment with dimethylhydrazine for 16 weeks, dimethylhydrazine was then discontinued for 8 weeks, followed by intravenous infusion of EGF for 1 week. There were four groups: vehicle alone, EGF alone, dimethylhydrazine alone, and dimethylhydrazine followed by EGF infusion. The rats were killed at 25 weeks and rates of intestinal crypt cell production, crypt size, and crypt fission were determined. Intravenously infused EGF significantly increased crypt cell production rate, but the magnitude of the effect decreased from the proximal to the distal colon. EGF caused an increase in crypt area, possibly reflecting an increase in crypt size. Importantly dimethylhydrazine had no significant effect on crypt cell production rate nor on crypt area in the distal colon, but it did cause an increase in crypt area in the mid-colon. The crypt fission index was significantly decreased by EGF and increased by dimethylhydrazine. There was no qualitative interaction between EGF and dimethylhydrazine. These results demonstrate the marked proliferative effect of intravenously infused EGF in the colon of orally fed rats, with significant site effects (P = 0.0007); the effect was greatest in the proximal colon and disappeared in the distal colon. The observation that EGF reduced crypt fission indicates that increased cell proliferation, per se, is not a stimulus for crypt fission. This is further supported by the observation that dimethylhydrazine

  13. Kidney tubular-cell secretion of osteoblast growth factor is increased by kaempferol: a scientific basis for "the kidney controlling the bone" theory of Chinese medicine.

    PubMed

    Long, Mian; Li, Shun-xiang; Xiao, Jiang-feng; Wang, Jian; Lozanoff, Scott; Zhang, Zhi-guang; Luft, Benjamin J; Johnson, Francis

    2014-09-01

    To study, at the cytological level, the basic concept of Chinese medicine that "the Kidney (Shen) controls the bone". Kaempferol was isolated form Rhizoma Drynariae (Gu Sui Bu, GSB) and at several concentrations was incubated with opossum kidney (OK) cells, osteoblasts (MC3T3 E1) and human fibroblasts (HF) at cell concentrations of 2×10(4)/mL. Opossum kidney cell-conditioned culture media with kaempferol at 70 nmol/L (70kaeOKM) and without kaempferol (0OKM) were used to stimulate MC3T3 E1 and HF proliferation. The bone morphological protein receptors I and II (BMPR I and II) in OK cells were identified by immune-fluorescence staining and Western blot analysis. Kaempferol was found to increase OK cell growth (P<0.05), but alone did not promote MC3T3 E1 or HF cell proliferation. However, although OKM by itself increased MC3T3 E1 growth by 198% (P<0.01), the 70kaeOKM further increased the growth of these cells by an additional 127% (P<0.01). It indicates that the kidney cell generates a previously unknown osteoblast growth factor (OGF) and kaempferol increases kidney cell secretion of OGF. Neither of these media had any significant effect on HF growth. Kaempferol also was found to increase the level of the BMPR II in OK cells. This lends strong support to the original idea that the Kidney has a significant influence over bone-formation, as suggested by some long-standing Chinese medical beliefs, kaempferol may also serve to stimulate kidney repair and indirectly stimulate bone formation.

  14. Modulation of a P-TEFb Functional Equilibrium for the Global Control of Cell Growth and Differentiation

    PubMed Central

    He, Nanhai; Pezda, Andrea C.; Zhou, Qiang

    2006-01-01

    P-TEFb phosphorylates RNA polymerase II and negative elongation factors to stimulate general transcriptional elongation. It is kept in a functional equilibrium through alternately interacting with its positive (the Brd4 protein) and negative (the HEXIM1 protein and 7SK snRNA) regulators. To investigate the physiological significance of this phenomenon, we analyzed the responses of HeLa cells and murine erythroleukemia cells (MELC) to hexamethylene bisacetamide (HMBA), which inhibits growth and induces differentiation of many cell types. For both cell types, an efficient, albeit temporary disruption of the 7SK-HEXIM1-P-TEFb snRNP and enhanced formation of the Brd4-P-TEFb complex occurred soon after the treatment started. When the P-TEFb-dependent HEXIM1 expression markedly increased as the treatment continued, the abundant HEXIM1 pushed the P-TEFb equilibrium back toward the 7SK/HEXIM1-bound state. For HeLa cells, as HMBA produced only a minor, temporary effect on their growth, the equilibrium gradually returned to its pretreatment level. In contrast, long-term treatment of MELC induced terminal division and differentiation. Concurrently, the P-TEFb equilibrium was shifted overwhelmingly toward the 7SK snRNP side. Together, these data link the P-TEFb equilibrium to the intracellular transcriptional demand and proliferative/differentiated states of cells. PMID:16980611

  15. Growth laws and mechanisms of global control in bacteria

    NASA Astrophysics Data System (ADS)

    Scott, Matthew

    2009-03-01

    The growth laws of Schaechter, Maaløe and Kjeldgaard are among the most striking discoveries in bacterial growth physiology: cell composition (mass/cell, RNA/cell, etc.) is a simple function of growth rate alone -- irrespective of how that growth rate is established. I will review the growth laws, and discuss recent experiments that have uncovered new laws. A systems-level mathematical model is developed that suggests the growth laws arise from the partitioning of the protein synthesizing machinery of the cell (the ribosomes), and furthermore indicates a deep connection between growth rate control and central metabolism.

  16. Cellulose and the Control of Growth Anisotropy

    SciTech Connect

    Tobias I. Baskin

    2004-04-01

    The authors research aims to understand morphogenesis, focusing on growth anisotropy, a process that is crucial to make organs with specific and heritable shapes. For the award, the specific aims were to test hypotheses concerning how growth anisotropy is controlled by cell wall structure, particularly by the synthesis and alignment of cellulose microfibrils, the predominant mechanical element in the cell wall. This research has involved characterizing the basic physiology of anisotropic expansion, including measuring it at high resolution; and second, characterizing the relationship between growth anisotropy, and cellulose microfibrils. Important in this relationship and also to the control of anisotropic expansion are structures just inside the plasma membrane called cortical microtubules, and the research has also investigated their contribution to controlling anisotropy and microfibril alignment. In addition to primary experimental papers, I have also developed improved methods relating to these objectives as well as written relevant reviews. Major accomplishments in each area will now be described.

  17. Control of Retinal Ganglion Cell Positioning and Neurite Growth: Combining 3D Printing with Radial Electrospun Scaffolds.

    PubMed

    Kador, Karl E; Grogan, Shawn P; Dorthé, Erik W; Venugopalan, Praseeda; Malek, Monisha F; Goldberg, Jeffrey L; D'lima, Darryl D

    2016-02-01

    Retinal ganglion cells (RGCs) are responsible for the transfer of signals from the retina to the brain. As part of the central nervous system, RGCs are unable to regenerate following injury, and implanted cells have limited capacity to orient and integrate in vivo. During development, secreted guidance molecules along with signals from extracellular matrix and the vasculature guide cell positioning, for example, around the fovea, and axon outgrowth; however, these changes are temporally regulated and are not the same in the adult. Here, we combine electrospun cell transplantation scaffolds capable of RGC neurite guidance with thermal inkjet 3D cell printing techniques capable of precise positioning of RGCs on the scaffold surface. Optimal printing parameters are developed for viability, electrophysiological function and, neurite pathfinding. Different media, commonly used to promote RGC survival and growth, were tested under varying conditions. When printed in growth media containing both brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF), RGCs maintained survival and normal electrophysiological function, and displayed radial axon outgrowth when printed onto electrospun scaffolds. These results demonstrate that 3D printing technology may be combined with complex electrospun surfaces in the design of future retinal models or therapies.

  18. Control of Retinal Ganglion Cell Positioning and Neurite Growth: Combining 3D Printing with Radial Electrospun Scaffolds

    PubMed Central

    Kador, Karl E.; Grogan, Shawn P.; Dorthé, Erik W.; Venugopalan, Praseeda; Malek, Monisha F.

    2016-01-01

    Retinal ganglion cells (RGCs) are responsible for the transfer of signals from the retina to the brain. As part of the central nervous system, RGCs are unable to regenerate following injury, and implanted cells have limited capacity to orient and integrate in vivo. During development, secreted guidance molecules along with signals from extracellular matrix and the vasculature guide cell positioning, for example, around the fovea, and axon outgrowth; however, these changes are temporally regulated and are not the same in the adult. Here, we combine electrospun cell transplantation scaffolds capable of RGC neurite guidance with thermal inkjet 3D cell printing techniques capable of precise positioning of RGCs on the scaffold surface. Optimal printing parameters are developed for viability, electrophysiological function and, neurite pathfinding. Different media, commonly used to promote RGC survival and growth, were tested under varying conditions. When printed in growth media containing both brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF), RGCs maintained survival and normal electrophysiological function, and displayed radial axon outgrowth when printed onto electrospun scaffolds. These results demonstrate that 3D printing technology may be combined with complex electrospun surfaces in the design of future retinal models or therapies. PMID:26729061

  19. Controllable growth of dendritic ZnO nanowire arrays on a stainless steel mesh towards the fabrication of large area, flexible dye-sensitized solar cells.

    PubMed

    Dai, Hui; Zhou, Yong; Liu, Qi; Li, Zhengdao; Bao, Chunxiong; Yu, Tao; Zhou, Zhigang

    2012-09-07

    Well-defined ZnO nanowire (NW) arrays with controlled dendritic structures were successfully built on a stainless steel mesh and utilized as photoanodes for the fabrication of large-area, flexible dye-sensitized solar cells (DSSCs). The dendritic nanostructure proves favorable for the improvement of the overall light conversion efficiency of the DSSC. An optimized etching time for the affixion of ZnO seeds on the ZnO backbone of the dendritic "tree" and the controlled growth conditions of the branch NW are critical to achieve high conversion efficiency solar cells.

  20. Controllable growth of dendritic ZnO nanowire arrays on a stainless steel mesh towards the fabrication of large area, flexible dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Dai, Hui; Zhou, Yong; Liu, Qi; Li, Zhengdao; Bao, Chunxiong; Yu, Tao; Zhou, Zhigang

    2012-08-01

    Well-defined ZnO nanowire (NW) arrays with controlled dendritic structures were successfully built on a stainless steel mesh and utilized as photoanodes for the fabrication of large-area, flexible dye-sensitized solar cells (DSSCs). The dendritic nanostructure proves favorable for the improvement of the overall light conversion efficiency of the DSSC. An optimized etching time for the affixion of ZnO seeds on the ZnO backbone of the dendritic ``tree'' and the controlled growth conditions of the branch NW are critical to achieve high conversion efficiency solar cells.

  1. The Control of Arabidopsis thaliana Growth by Cell Proliferation and Endoreplication Requires the F-Box Protein FBL17.

    PubMed

    Noir, Sandra; Marrocco, Katia; Masoud, Kinda; Thomann, Alexis; Gusti, Andi; Bitrian, Marta; Schnittger, Arp; Genschik, Pascal

    2015-05-01

    A key step of the cell cycle is the entry into the DNA replication phase that typically commits cells to divide. However, little is known about the molecular mechanisms regulating this transition in plants. Here, we investigated the function of FBL17 (F BOX-LIKE17), an Arabidopsis thaliana F-box protein previously shown to govern the progression through the second mitosis during pollen development. Our work reveals that FBL17 function is not restricted to gametogenesis. FBL17 transcripts accumulate in both proliferating and postmitotic cell types of Arabidopsis plants. Loss of FBL17 function drastically reduces plant growth by altering cell division activity in both shoot and root apical meristems. In fbl17 mutant plants, DNA replication is severely impaired and endoreplication is fully suppressed. At the molecular level, lack of FBL17 increases the stability of the CDK (CYCLIN-DEPENDENT KINASE) inhibitor KIP-RELATED PROTEIN2 known to switch off CDKA;1 kinase activity. Despite the strong inhibition of cell proliferation in fbl17, some cells are still able to enter S phase and eventually to divide, but they exhibit a strong DNA damage response and often missegregate chromosomes. Altogether, these data indicate that the F-box protein FBL17 acts as a master cell cycle regulator during the diploid sporophyte phase of the plant. © 2015 American Society of Plant Biologists. All rights reserved.

  2. Nucleation and growth control in protein crystallization

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz; Nyce, Thomas A.; Meehan, Edward J.; Sowers, Jennifer W.; Monaco, Lisa A.

    1990-01-01

    The five topics summarized in this final report are as follows: (1) a technique for the expedient, semi-automated determination of protein solubilities as a function of temperature and application of this technique to proteins other than lysozyme; (2) a small solution cell with adjustable temperature gradients for the growth of proteins at a predetermined location through temperature programming; (3) a microscopy system with image storage and processing capability for high resolution optical studies of temperature controlled protein growth and etching kinetics; (4) growth experiments with lysozyme in thermosyphon flow ; and (5) a mathematical model for the evolution of evaporation/diffusion induced concentration gradients in the hanging drop protein crystallization technique.

  3. β-Arrestin1/miR-326 Transcription Unit Is Epigenetically Regulated in Neural Stem Cells Where It Controls Stemness and Growth Arrest

    PubMed Central

    Begalli, Federica; Abballe, Luana; Catanzaro, Giuseppina; Vacca, Alessandra; Napolitano, Maddalena; Tafani, Marco; Giangaspero, Felice; Locatelli, Franco

    2017-01-01

    Cell development is regulated by a complex network of mRNA-encoded proteins and microRNAs, all funnelling onto the modulation of self-renewal or differentiation genes. How intragenic microRNAs and their host genes are transcriptionally coregulated and their functional relationships for the control of neural stem cells (NSCs) are poorly understood. We propose here the intragenic miR-326 and its host gene β-arrestin1 as novel players whose epigenetic silencing maintains stemness in normal cerebellar stem cells. Such a regulation is mediated by CpG islands methylation of the common promoter. Epigenetic derepression of β-arrestin1/miR-326 by differentiation signals or demethylating agents leads to suppression of stemness features and cell growth and promotes cell differentiation. β-Arrestin1 inhibits cell proliferation by enhancing the nuclear expression of the cyclin-dependent kinase inhibitor p27. Therefore, we propose a new mechanism for the control of cerebellar NSCs where a coordinated epigenetic mechanism finely regulates β-arrestin1/miR-326 expression and consequently NSCs stemness and cell growth. PMID:28298929

  4. Spatiotemporal Regulation of Chondrogenic Differentiation with Controlled Delivery of Transforming Growth Factor-β1 from Gelatin Microspheres in Mesenchymal Stem Cell Aggregates

    PubMed Central

    Solorio, Loran D.; Dhami, Chirag D.; Dang, Phuong N.; Vieregge, Eran L.

    2012-01-01

    The precise spatial and temporal presentation of growth factors is critical for cartilage development, during which tightly controlled patterns of signals direct cell behavior and differentiation. Recently, chondrogenic culture of human mesenchymal stem cells (hMSCs) has been improved through the addition of polymer microspheres capable of releasing growth factors directly to cells within cellular aggregates, eliminating the need for culture in transforming growth factor-β1 (TGF-β1)-containing medium. However, the influence of specific patterns of spatiotemporal growth factor presentation on chondrogenesis within microsphere-incorporated cell systems is unclear. In this study, we examined the effects of altering the chondrogenic microenvironment within hMSC aggregates through varying microsphere amount, growth factor concentration per microsphere, and polymer degradation time. Cartilage formation was evaluated in terms of DNA, glycosaminoglycan, and type II collagen in hMSCs from three donors. Chondrogenesis equivalent to or greater than that of aggregates cultured in medium containing TGF-β1 was achieved in some conditions, with varied differentiation based on the specific conditions of microsphere incorporation. A more spatially distributed delivery of TGF-β1 from a larger mass of fast-degrading microspheres improved differentiation by comparison with delivery from a smaller mass of microspheres with a higher TGF-β1 concentration per microsphere, although the total amount of growth factor per aggregate was the same. Results also indicated that the rate and degree of chondrogenesis varied on a donor-to-donor basis. Overall, this study elucidates the effects of varied conditions of TGF-β1-loaded microsphere incorporation on hMSC chondrogenesis, demonstrating that both spatiotemporal growth factor presentation and donor variability influence chondrogenic differentiation within microsphere-incorporated cellular constructs. PMID:23197869

  5. Heteroresistance at the Single-Cell Level: Adapting to Antibiotic Stress through a Population-Based Strategy and Growth-Controlled Interphenotypic Coordination

    PubMed Central

    Wang, Xiaorong; Kang, Yu; Luo, Chunxiong; Zhao, Tong; Liu, Lin; Jiang, Xiangdan; Fu, Rongrong; An, Shuchang; Chen, Jichao; Jiang, Ning; Ren, Lufeng; Wang, Qi; Baillie, J. Kenneth; Gao, Zhancheng; Yu, Jun

    2014-01-01

    ABSTRACT Heteroresistance refers to phenotypic heterogeneity of microbial clonal populations under antibiotic stress, and it has been thought to be an allocation of a subset of “resistant” cells for surviving in higher concentrations of antibiotic. The assumption fits the so-called bet-hedging strategy, where a bacterial population “hedges” its “bet” on different phenotypes to be selected by unpredicted environment stresses. To test this hypothesis, we constructed a heteroresistance model by introducing a blaCTX-M-14 gene (coding for a cephalosporin hydrolase) into a sensitive Escherichia coli strain. We confirmed heteroresistance in this clone and that a subset of the cells expressed more hydrolase and formed more colonies in the presence of ceftriaxone (exhibited stronger “resistance”). However, subsequent single-cell-level investigation by using a microfluidic device showed that a subset of cells with a distinguishable phenotype of slowed growth and intensified hydrolase expression emerged, and they were not positively selected but increased their proportion in the population with ascending antibiotic concentrations. Therefore, heteroresistance—the gradually decreased colony-forming capability in the presence of antibiotic—was a result of a decreased growth rate rather than of selection for resistant cells. Using a mock strain without the resistance gene, we further demonstrated the existence of two nested growth-centric feedback loops that control the expression of the hydrolase and maximize population growth in various antibiotic concentrations. In conclusion, phenotypic heterogeneity is a population-based strategy beneficial for bacterial survival and propagation through task allocation and interphenotypic collaboration, and the growth rate provides a critical control for the expression of stress-related genes and an essential mechanism in responding to environmental stresses. PMID:24520060

  6. Tobacco Translationally Controlled Tumor Protein Interacts with Ethylene Receptor Tobacco Histidine Kinase1 and Enhances Plant Growth through Promotion of Cell Proliferation.

    PubMed

    Tao, Jian-Jun; Cao, Yang-Rong; Chen, Hao-Wei; Wei, Wei; Li, Qing-Tian; Ma, Biao; Zhang, Wan-Ke; Chen, Shou-Yi; Zhang, Jin-Song

    2015-09-01

    Ethylene is an important phytohormone in the regulation of plant growth, development, and stress response throughout the lifecycle. Previously, we discovered that a subfamily II ethylene receptor tobacco (Nicotiana tabacum) Histidine Kinase1 (NTHK1) promotes seedling growth. Here, we identified an NTHK1-interacting protein translationally controlled tumor protein (NtTCTP) by the yeast (Saccharomyces cerevisiae) two-hybrid assay and further characterized its roles in plant growth. The interaction was further confirmed by in vitro glutathione S-transferase pull down and in vivo coimmunoprecipitation and bimolecular fluorescence complementation assays, and the kinase domain of NTHK1 mediates the interaction with NtTCTP. The NtTCTP protein is induced by ethylene treatment and colocalizes with NTHK1 at the endoplasmic reticulum. Overexpression of NtTCTP or NTHK1 reduces plant response to ethylene and promotes seedling growth, mainly through acceleration of cell proliferation. Genetic analysis suggests that NtTCTP is required for the function of NTHK1. Furthermore, association of NtTCTP prevents NTHK1 from proteasome-mediated protein degradation. Our data suggest that plant growth inhibition triggered by ethylene is regulated by a unique feedback mechanism, in which ethylene-induced NtTCTP associates with and stabilizes ethylene receptor NTHK1 to reduce plant response to ethylene and promote plant growth through acceleration of cell proliferation.

  7. Tobacco Translationally Controlled Tumor Protein Interacts with Ethylene Receptor Tobacco Histidine Kinase1 and Enhances Plant Growth through Promotion of Cell Proliferation1[OPEN

    PubMed Central

    Tao, Jian-Jun; Cao, Yang-Rong; Chen, Hao-Wei; Wei, Wei; Li, Qing-Tian; Ma, Biao; Zhang, Wan-Ke; Chen, Shou-Yi; Zhang, Jin-Song

    2015-01-01

    Ethylene is an important phytohormone in the regulation of plant growth, development, and stress response throughout the lifecycle. Previously, we discovered that a subfamily II ethylene receptor tobacco (Nicotiana tabacum) Histidine Kinase1 (NTHK1) promotes seedling growth. Here, we identified an NTHK1-interacting protein translationally controlled tumor protein (NtTCTP) by the yeast (Saccharomyces cerevisiae) two-hybrid assay and further characterized its roles in plant growth. The interaction was further confirmed by in vitro glutathione S-transferase pull down and in vivo coimmunoprecipitation and bimolecular fluorescence complementation assays, and the kinase domain of NTHK1 mediates the interaction with NtTCTP. The NtTCTP protein is induced by ethylene treatment and colocalizes with NTHK1 at the endoplasmic reticulum. Overexpression of NtTCTP or NTHK1 reduces plant response to ethylene and promotes seedling growth, mainly through acceleration of cell proliferation. Genetic analysis suggests that NtTCTP is required for the function of NTHK1. Furthermore, association of NtTCTP prevents NTHK1 from proteasome-mediated protein degradation. Our data suggest that plant growth inhibition triggered by ethylene is regulated by a unique feedback mechanism, in which ethylene-induced NtTCTP associates with and stabilizes ethylene receptor NTHK1 to reduce plant response to ethylene and promote plant growth through acceleration of cell proliferation. PMID:25941315

  8. Ezh2 Controls an Early Hematopoietic Program and Growth and Survival Signaling in Early T Cell Precursor Acute Lymphoblastic Leukemia.

    PubMed

    Danis, Etienne; Yamauchi, Taylor; Echanique, Kristen; Zhang, Xi; Haladyna, Jessica N; Riedel, Simone S; Zhu, Nan; Xie, Huafeng; Orkin, Stuart H; Armstrong, Scott A; Bernt, Kathrin M; Neff, Tobias

    2016-03-01

    Early T cell precursor acute lymphoblastic leukemia (ETP-ALL) is an aggressive subtype of ALL distinguished by stem-cell-associated and myeloid transcriptional programs. Inactivating alterations of Polycomb repressive complex 2 components are frequent in human ETP-ALL, but their functional role is largely undefined. We have studied the involvement of Ezh2 in a murine model of NRASQ61K-driven leukemia that recapitulates phenotypic and transcriptional features of ETP-ALL. Homozygous inactivation of Ezh2 cooperated with oncogenic NRASQ61K to accelerate leukemia onset. Inactivation of Ezh2 accentuated expression of genes highly expressed in human ETP-ALL and in normal murine early thymic progenitors. Moreover, we found that Ezh2 contributes to the silencing of stem-cell- and early-progenitor-cell-associated genes. Loss of Ezh2 also resulted in increased activation of STAT3 by tyrosine 705 phosphorylation. Our data mechanistically link Ezh2 inactivation to stem-cell-associated transcriptional programs and increased growth/survival signaling, features that convey an adverse prognosis in patients. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Distinct CCR2(+) Gr1(+) cells control growth of the Yersinia pestis ΔyopM mutant in liver and spleen during systemic plague.

    PubMed

    Ye, Zhan; Uittenbogaard, Annette M; Cohen, Donald A; Kaplan, Alan M; Ambati, Jayakrishna; Straley, Susan C

    2011-02-01

    We are using a systemic plague model to identify the cells and pathways that are undermined by the virulence protein YopM of the plague bacterium Yersinia pestis. In this study, we pursued previous findings that Gr1(+) cells are required to selectively limit growth of ΔyopM Y. pestis and that CD11b(+) cells other than polymorphonuclear leukocytes (PMNs) are selectively lost in spleens infected with parent Y. pestis. When PMNs were ablated from mice, ΔyopM Y. pestis grew as well as the parent strain in liver but not in spleen, showing that these cells are critical for controlling growth of the mutant in liver but not spleen. In mice lacking expression of the chemokine receptor CCR2, wild-type growth was restored to ΔyopM Y. pestis in both organs. In spleen, the Gr1(+) cells differentially recruited by parent and ΔyopM Y. pestis infections were CCR2(+) Gr1(+) CD11b(+) CD11c(Lo-Int) MAC3(+) iNOS(+) (inducible nitric oxide synthase-positive) inflammatory dendritic cells (iDCs), and their recruitment to spleen from blood was blocked when YopM was present in the infecting strain. Consistent with influx of iDCs being affected by YopM in spleen, the growth defect of the ΔyopM mutant was relieved by the parent Y. pestis strain in a coinfection assay in which the parent strain could affect the fate of the mutant in trans. In a mouse model of bubonic plague, CCR2 also was shown to be required for ΔyopM Y. pestis to show wild-type growth in skin. The data imply that YopM's pathogenic effect indirectly undermines signaling through CCR2. We propose a model for how YopM exerts its different effects in liver and spleen.

  10. FACTORS WHICH CONTROL MAXIMAL GROWTH OF BACTERIA

    PubMed Central

    Sinclair, N. A.; Stokes, J. L.

    1962-01-01

    Sinclair, N. A. (Washington State University, Pullman) and J. L. Stokes. Factors which control maximal growth of bacteria. J. Bacteriol. 83:1147–1154. 1962.—In a chemically defined medium containing 1% glucose and 0.1% (NH4)2SO4, both of these compounds are virtually exhausted by the growth of Pseudomonas fluorescens. If these carbon, energy, and nitrogen sources are added back to the culture filtrate, maximal growth to the level of the original culture is obtained. This process can be repeated several times with the same results. Eventually, however, the supply of minerals in the culture limits growth. When the nutrient levels are raised to 3% glucose and 0.3% (NH4)2SO4, lack of oxygen and low pH limit growth before the supply of nutrients is exhausted. There is no evidence that specific autoinhibitory substances are produced either in chemically defined or complex nitrogenous media or that physical crowding of the cells limits growth. The results with Escherichia coli are similar to those with P. fluorescens. However, after a few growth cycles aerobically and after only one growth cycle anaerobically, inhibitory substances, probably organic acids, accumulate and limit growth. PMID:13913264

  11. TEAD4-YAP interaction regulates tumoral growth by controlling cell-cycle arrest at the G1 phase.

    PubMed

    Takeuchi, Shin; Kasamatsu, Atsushi; Yamatoji, Masanobu; Nakashima, Dai; Endo-Sakamoto, Yosuke; Koide, Nao; Takahara, Toshikazu; Shimizu, Toshihiro; Iyoda, Manabu; Ogawara, Katsunori; Shiiba, Masashi; Tanzawa, Hideki; Uzawa, Katsuhiro

    2017-04-29

    TEA domain transcription factor 4 (TEAD4), which has critical functions in the process of embryonic development, is expressed in various cancers. However, the important role of TEAD4 in human oral squamous cell carcinomas (OSCCs) remain unclear. Here we investigated the TEAD4 expression level and the functional mechanism in OSCC using quantitative reverse transcriptase-polymerase chain reaction, Western blot analysis, and immunohistochemistry. Furthermore, TEAD4 knockdown model was used to evaluate cellular proliferation, cell-cycle analysis, and the interaction between TEAD4 and Yes-associated protein (YAP) which was reported to be a transcription coactivator of cellular proliferation. In the current study, we found that TEAD4 expression increased significantly in vitro and in vivo and correlated with tumoral size in OSCC patients. TEAD4 knockdown OSCC cells showed decreased cellular proliferation resulting from cell-cycle arrest in the G1 phase by down-regulation of cyclins, cyclin-dependent kinases (CDKs), and up-regulation of CDK inhibitors. We also found that the TEAD4-YAP complex in the nuclei may be related closely to transcriptions of G1 arrest-related genes. Taken together, we concluded that TEAD4 might play an important role in tumoral growth and have potential to be a therapeutic target in OSCCs. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Controlled Growth and the Maintenance of Human Pluripotent Stem Cells by Cultivation with Defined Medium on Extracellular Matrix-Coated Micropatterned Dishes

    PubMed Central

    Takenaka, Chiemi; Miyajima, Hiroshi; Yoda, Yusuke; Imazato, Hideo; Yamamoto, Takako; Gomi, Shinichi; Ohshima, Yasuhiro; Kagawa, Kenichi; Sasaki, Tetsuji; Kawamata, Shin

    2015-01-01

    Here, we introduce a new serum-free defined medium (SPM) that supports the cultivation of human pluripotent stem cells (hPSCs) on recombinant human vitronectin-N (rhVNT-N)-coated dishes after seeding with either cell clumps or single cells. With this system, there was no need for an intervening sequential adaptation process after moving hPSCs from feeder layer-dependent conditions. We also introduce a micropatterned dish that was coated with extracellular matrix by photolithographic technology. This procedure allowed the cultivation of hPSCs on 199 individual rhVNT-N-coated small round spots (1 mm in diameter) on each 35-mm polystyrene dish (termed “patterned culture”), permitting the simultaneous formation of 199 uniform high-density small-sized colonies. This culture system supported controlled cell growth and maintenance of undifferentiated hPSCs better than dishes in which the entire surface was coated with rhVNT-N (termed “non-patterned cultures”). Non-patterned cultures produced variable, unrestricted cell proliferation with non-uniform cell growth and uneven densities in which we observed downregulated expression of some self-renewal-related markers. Comparative flow cytometric studies of the expression of pluripotency-related molecules SSEA-3 and TRA-1-60 in hPSCs from non-patterned cultures and patterned cultures supported this concept. Patterned cultures of hPSCs allowed sequential visual inspection of every hPSC colony, giving an address and number in patterned culture dishes. Several spots could be sampled for quality control tests of production batches, thereby permitting the monitoring of hPSCs in a single culture dish. Our new patterned culture system utilizing photolithography provides a robust, reproducible and controllable cell culture system and demonstrates technological advantages for the mass production of hPSCs with process quality control. PMID:26115194

  13. Controlled Growth and the Maintenance of Human Pluripotent Stem Cells by Cultivation with Defined Medium on Extracellular Matrix-Coated Micropatterned Dishes.

    PubMed

    Takenaka, Chiemi; Miyajima, Hiroshi; Yoda, Yusuke; Imazato, Hideo; Yamamoto, Takako; Gomi, Shinichi; Ohshima, Yasuhiro; Kagawa, Kenichi; Sasaki, Tetsuji; Kawamata, Shin

    2015-01-01

    Here, we introduce a new serum-free defined medium (SPM) that supports the cultivation of human pluripotent stem cells (hPSCs) on recombinant human vitronectin-N (rhVNT-N)-coated dishes after seeding with either cell clumps or single cells. With this system, there was no need for an intervening sequential adaptation process after moving hPSCs from feeder layer-dependent conditions. We also introduce a micropatterned dish that was coated with extracellular matrix by photolithographic technology. This procedure allowed the cultivation of hPSCs on 199 individual rhVNT-N-coated small round spots (1 mm in diameter) on each 35-mm polystyrene dish (termed "patterned culture"), permitting the simultaneous formation of 199 uniform high-density small-sized colonies. This culture system supported controlled cell growth and maintenance of undifferentiated hPSCs better than dishes in which the entire surface was coated with rhVNT-N (termed "non-patterned cultures"). Non-patterned cultures produced variable, unrestricted cell proliferation with non-uniform cell growth and uneven densities in which we observed downregulated expression of some self-renewal-related markers. Comparative flow cytometric studies of the expression of pluripotency-related molecules SSEA-3 and TRA-1-60 in hPSCs from non-patterned cultures and patterned cultures supported this concept. Patterned cultures of hPSCs allowed sequential visual inspection of every hPSC colony, giving an address and number in patterned culture dishes. Several spots could be sampled for quality control tests of production batches, thereby permitting the monitoring of hPSCs in a single culture dish. Our new patterned culture system utilizing photolithography provides a robust, reproducible and controllable cell culture system and demonstrates technological advantages for the mass production of hPSCs with process quality control.

  14. MicroRNA-30b controls endothelial cell capillary morphogenesis through regulation of transforming growth factor beta 2.

    PubMed

    Howe, Grant A; Kazda, Kayla; Addison, Christina L

    2017-01-01

    The importance of microRNA (miRNA) to vascular biology is becoming increasingly evident; however, the function of a significant number of miRNA remains to be determined. In particular, the effect of growth factor regulation of miRNAs on endothelial cell morphogenesis is incomplete. Thus, we aimed to identify miRNAs regulated by pro-angiogenic vascular endothelial growth factor (VEGF) and determine the effects of VEGF-regulated miRNAs and their targets on processes important for angiogenesis. Human umbilical vein endothelial cells (HUVECs) were thus stimulated with VEGF and miRNA levels assessed using microarrays. We found that VEGF altered expression of many miRNA, and for this study focused on one of the most significantly down-regulated miRNA in HUVECs following VEGF treatment, miR-30b. Using specific miRNA mimics, we found that overexpression of miR-30b inhibited capillary morphogenesis in vitro, while depletion of endogenous miR-30b resulted in increased capillary morphogenesis indicating the potential significance of down-regulation of miR-30b as a pro-angiogenic response to VEGF stimulation. MiR-30b overexpression in HUVEC regulated transforming growth factor beta 2 (TGFβ2) production, which led to increased phosphorylation of Smad2, indicating activation of an autocrine TGFβ signaling pathway. Up-regulation of TGFβ2 by miR-30b overexpression was found to be dependent on ATF2 activation, a transcription factor known to regulate TGFβ2 expression, as miR-30b overexpressing cells exhibited increased levels of phosphorylated ATF2 and depletion of ATF2 inhibited miR-30b-induced TGFβ2 expression. However, miR-30b effects on ATF2 were indirect and found to be via targeting of the known ATF2 repressor protein JDP2 whose mRNA levels were indirectly correlated with miR-30b levels. Increased secretion of TGFβ2 from HUVEC was shown to mediate the inhibitory effects of miR-30b on capillary morphogenesis as treatment with a neutralizing antibody to TGFβ2 restored

  15. S6K1 and E2FB are in mutually antagonistic regulatory links controlling cell growth and proliferation in Arabidopsis.

    PubMed

    Henriques, Rossana; Magyar, Zoltán; Bögre, László

    2013-06-01

    Plant development is dependent on the coordination between growth and cell proliferation. The nutrient sensing TOR kinase and its downstream target, the 40S ribosomal S6 Kinase, are central controllers of cell growth that were also shown to determine cell size by inhibiting the onset of mitosis in yeast and animal cells. We have shown that the Arabidopsis S6 Kinase1 inhibits cell proliferation through the RBR-E2FB complex. S6K1 interacts with RBR via its N-terminal RBR binding motif, promotes its nuclear localization and consequent RBR-dependent repression of cell cycle genes through E2FB. Here we show that S6K1 and E2FB are in a mutually antagonistic relationship both in their protein abundance and in their activity. We propose that this double inhibitory regulatory connection between S6K1 and E2FB forms a regulatory switch that might be important to determine whether cells divide or grow.

  16. Ablation of the Retinoblastoma gene family deregulates G1 control causing immortalization and increased cell turnover under growth-restricting conditions

    PubMed Central

    Dannenberg, Jan-Hermen; van Rossum, Agnes; Schuijff, Leontine; te Riele, Hein

    2000-01-01

    The retinoblastoma suppressor pRB belongs to the family of so-called pocket proteins, which also includes p107 and p130. These proteins may functionally overlap in cell cycle control and tumor suppression. We have generated an isogenic set of embryonic stem (ES) cell lines carrying single or compound loss-of-function mutations in the Rb gene family, including a cell line completely devoid of all three pocket proteins. None of the knockout combinations affected the growth characteristics of ES cells; however, concomitant ablation of all three pocket proteins strongly impaired their differentiation capacity. For the generated genotypes, primary mouse embryonic fibroblasts (MEFs) also were obtained. While inactivation of Rb alone did not alleviate the senescence response of MEFs, pRB/p107-deficient MEFs, after having adapted to in vitro culturing, continued to proliferate at modest rate. Additional ablation of p130 rendered MEFs completely insensitive to senescence-inducing signals and strongly increased their proliferation rate. Although triple-knockout MEFs retained anchorage dependence, they lacked proper G1 control and showed increased cell turnover under growth-inhibiting conditions. PMID:11114893

  17. PROSPECT - GROWTH FACTOR CONTROL OF BONE MASS

    PubMed Central

    Canalis, Ernesto

    2010-01-01

    Bone formation is determined by the number and function of osteoblasts. Cell number is governed by factors that regulate the replication and differentiation of pre-osteoblasts and factors that regulate osteoblastic cell death. Cell function is controlled by signals acting on the mature osteoblast. Platelet derived and fibroblast growth factors are bone cell mitogens. Bone morphogenetic proteins (BMP) and Wnt induce the differentiation of mesenchymal cells toward osteoblasts, and insulin-like growth factor (IGF)-I stimulates the function of mature osteoblasts and prevents their death. The activity of BMP, Wnt and IGF-I is modulated by extracellular antagonists or binding proteins. Changes in growth factor synthesis and activity may play a role in the pathogenesis of selected forms of osteoporosis, and alterations in the expression or binding of the extracellular antagonists can be associated with changes in bone mass. Current approaches to bone anabolic therapies for osteoporosis include the administration of a growth factor, such as IGF-I, or the neutralization of an antagonist. Ideally, the targeting of an anabolic agent should be specific to bone to preclude non-skeletal unwanted side effects. Clinical trials are needed to determine the long-term effectiveness and safety of novel anabolic agents for the management of osteoporosis. PMID:19718659

  18. Identification of cancer-associated missense mutations in hace1 that impair cell growth control and Rac1 ubiquitylation

    PubMed Central

    Andrio, Emilie; Lotte, Romain; Hamaoui, Daniel; Cherfils, Jacqueline; Doye, Anne; Daugaard, Mads; Sorensen, Poul H.; Bost, Frédéric; Ruimy, Raymond; Mettouchi, Amel; Lemichez, Emmanuel

    2017-01-01

    The E3 ubiquitin ligase HACE1 is a potent tumor suppressor that controls cell proliferation and ubiquitylates the small GTPase Rac1 to target it to proteasomal degradation. Whether and how the activity of HACE1 is regulated by the N-terminal ankyrin (ANK) and the middle (MID) domains is ill defined. Here, we identified in the version 64 of the Catalogue of Somatic Mutations in Cancer (COSMIC) 13 missense mutations of hace1 located outside the HECT domain, and found that all lead to defective control of cell proliferation. In addition, several mutations located in the ankyrin domain displayed a dramatic reduction in Rac1 ubiquitylation associated with a decrease of colony formation in soft agar. 3D structure modelling of the 7 ankyrin-repeats coupled to functional analysis identified a surface epitope centered on one of the mutated residue, Gly-175, which is critical for controlling Rac1 binding and ubiquitylation. We also identified a role for the MID domain in conferring the specificity of association of HACE1 to the active form of Rac1. Our study of the functional interplay between HACE1 and Rac1 in cancer thus sheds a new light on the molecular mechanism of Rac1 ubiquitylation by HACE1 and the impact of its cancer-associated mutations in cell proliferation. PMID:28317937

  19. In-situ microfluidic controlled, low temperature hydrothermal growth of nanoflakes for dye-sensitized solar cells

    PubMed Central

    Zhao, Chao; Zhang, Jia; Hu, Yue; Robertson, Neil; Hu, Ping An; Child, David; Gibson, Desmond; Fu, Yong Qing

    2015-01-01

    In this paper, an in-situ microfluidic control unit (MCU) was designed and applied in a hydrothermal synthesis process, which provides an easy way to localize liquid-phase reaction and realize selective synthesis and direct growth of nanostructures as well as their morphology, all in a low-temperature and atmospheric environment. The morphology was controlled through controlling the amount of additivities using the MCU. This achieved a facile fabrication of Al doped ZnO (AZO) nanoflakes vertically grown on flexible polymer substrates with enhanced light scattering and dye loading capabilities. Flexible DSSCs with a significant enhancement (410% compare to ZnO NRs based devices) in power conversion efficiency were obtained using AZO nanoflake photoanodes of 6 μm thick, due to the enhancement in electron mobility and reduction in recombination. This hydrothermal synthesis using the in-situ MCU provides an efficient and scalable technique to synthesize controllable nanostructures with characteristics of easy set-up, low energy consumption and low cost. PMID:26631685

  20. In-situ microfluidic controlled, low temperature hydrothermal growth of nanoflakes for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Zhao, Chao; Zhang, Jia; Hu, Yue; Robertson, Neil; Hu, Ping An; Child, David; Gibson, Desmond; Fu, Yong Qing

    2015-12-01

    In this paper, an in-situ microfluidic control unit (MCU) was designed and applied in a hydrothermal synthesis process, which provides an easy way to localize liquid-phase reaction and realize selective synthesis and direct growth of nanostructures as well as their morphology, all in a low-temperature and atmospheric environment. The morphology was controlled through controlling the amount of additivities using the MCU. This achieved a facile fabrication of Al doped ZnO (AZO) nanoflakes vertically grown on flexible polymer substrates with enhanced light scattering and dye loading capabilities. Flexible DSSCs with a significant enhancement (410% compare to ZnO NRs based devices) in power conversion efficiency were obtained using AZO nanoflake photoanodes of 6 μm thick, due to the enhancement in electron mobility and reduction in recombination. This hydrothermal synthesis using the in-situ MCU provides an efficient and scalable technique to synthesize controllable nanostructures with characteristics of easy set-up, low energy consumption and low cost.

  1. Method for crystal growth control

    DOEpatents

    Yates, Douglas A.; Hatch, Arthur E.; Goldsmith, Jeff M.

    1981-01-01

    The growth of a crystalline body of a selected material is controlled so that the body has a selected cross-sectional shape. The apparatus is of the type which includes the structure normally employed in known capillary die devices as well as means for observing at least the portion of the surfaces of the growing crystalline body and the meniscus (of melt material from which the body is being pulled) including the solid/liquid/vapor junction in a direction substantially perpendicular to the meniscus surface formed at the junction when the growth of the crystalline body is under steady state conditions. The cross-sectional size of the growing crystalline body can be controlled by determining which points exhibit a sharp change in the amount of reflected radiation of a preselected wavelength and controlling the speed at which the body is being pulled or the temperature of the growth pool of melt so as to maintain those points exhibiting a sharp change at a preselected spatial position relative to a predetermined reference position. The improvement comprises reference object means positioned near the solid/liquid/vapor junction and capable of being observed by the means for observing so as to define said reference position so that the problems associated with convection current jitter are overcome.

  2. Ethylene Antagonizes Salt-Induced Growth Retardation and Cell Death Process via Transcriptional Controlling of Ethylene-, BAG- and Senescence-Associated Genes in Arabidopsis

    PubMed Central

    Pan, Ya-Jie; Liu, Ling; Lin, Ying-Chao; Zu, Yuan-Gang; Li, Lei-Peng; Tang, Zhong-Hua

    2016-01-01

    The existing question whether ethylene is involved in the modulation of salt-induced cell death to mediate plant salt tolerance is important for understanding the salt tolerance mechanisms. Here, we employed Arabidopsis plants to study the possible role of ethylene in salt-induced growth inhibition and programmed cell death (PCD) profiles. The root length, DNA ladder and cell death indicated by Evan's blue detection were measured by compared to the control or salt-stressed seedlings. Secondly, the protoplasts isolated from plant leaves and dyed with Annexin V-FITC were subjected to flow cytometric (FCM) assay. Our results showed that ethylene works effectively in seedling protoplasts, antagonizing salt-included root retardation and restraining cell death both in seedlings or protoplasts. Due to salinity, the entire or partial insensitivity of ethylene signaling resulted in an elevated levels of cell death in ein2-5 and ein3-1 plants and the event were amended in ctr1-1 plants after salt treatment. The subsequent experiment with exogenous ACC further corroborated that ethylene could modulate salt-induced PCD process actively. Plant Bcl-2-associated athanogene (BAG) family genes are recently identified to play an extensive role in plant PCD processes ranging from growth, development to stress responses and even cell death. Our result showed that salinity alone significantly suppressed the transcripts of BAG6, BAG7 and addition of ACC in the saline solution could obviously re-activate BAG6 and BAG7 expressions, which might play a key role to inhibit the salt-induced cell death. In summary, our research implies that ethylene and salinity antagonistically control BAG family-, ethylene-, and senescence-related genes to alleviate the salt-induced cell death. PMID:27242886

  3. Cell Biology of Hyphal Growth.

    PubMed

    Steinberg, Gero; Peñalva, Miguel A; Riquelme, Meritxell; Wösten, Han A; Harris, Steven D

    2017-04-01

    Filamentous fungi are a large and ancient clade of microorganisms that occupy a broad range of ecological niches. The success of filamentous fungi is largely due to their elongate hypha, a chain of cells, separated from each other by septa. Hyphae grow by polarized exocytosis at the apex, which allows the fungus to overcome long distances and invade many substrates, including soils and host tissues. Hyphal tip growth is initiated by establishment of a growth site and the subsequent maintenance of the growth axis, with transport of growth supplies, including membranes and proteins, delivered by motors along the cytoskeleton to the hyphal apex. Among the enzymes delivered are cell wall synthases that are exocytosed for local synthesis of the extracellular cell wall. Exocytosis is opposed by endocytic uptake of soluble and membrane-bound material into the cell. The first intracellular compartment in the endocytic pathway is the early endosomes, which emerge to perform essential additional functions as spatial organizers of the hyphal cell. Individual compartments within septated hyphae can communicate with each other via septal pores, which allow passage of cytoplasm or organelles to help differentiation within the mycelium. This article introduces the reader to more detailed aspects of hyphal growth in fungi.

  4. Alveolar epithelial cells are critical in protection of the respiratory tract by secretion of factors able to modulate the activity of pulmonary macrophages and directly control bacterial growth.

    PubMed

    Chuquimia, Olga D; Petursdottir, Dagbjort H; Periolo, Natalia; Fernández, Carmen

    2013-01-01

    The respiratory epithelium is a physical and functional barrier actively involved in the clearance of environmental agents. The alveolar compartment is lined with membranous pneumocytes, known as type I alveolar epithelial cells (AEC I), and granular pneumocytes, type II alveolar epithelial cells (AEC II). AEC II are responsible for epithelial reparation upon injury and ion transport and are very active immunologically, contributing to lung defense by secreting antimicrobial factors. AEC II also secrete a broad variety of factors, such as cytokines and chemokines, involved in activation and differentiation of immune cells and are able to present antigen to specific T cells. Another cell type important in lung defense is the pulmonary macrophage (PuM). Considering the architecture of the alveoli, a good communication between the external and the internal compartments is crucial to mount effective responses. Our hypothesis is that being in the interface, AEC may play an important role in transmitting signals from the external to the internal compartment and in modulating the activity of PuM. For this, we collected supernatants from AEC unstimulated or stimulated in vitro with lipopolysaccharide (LPS). These AEC-conditioned media were used in various setups to test for the effects on a number of macrophage functions: (i) migration, (ii) phagocytosis and intracellular control of bacterial growth, and (iii) phenotypic changes and morphology. Finally, we tested the direct effect of AEC-conditioned media on bacterial growth. We found that AEC-secreted factors had a dual effect, on one hand controlling bacterial growth and on the other hand increasing macrophage activity.

  5. MicroRNA-26a/cyclin-dependent kinase 5 axis controls proliferation, apoptosis and in vivo tumor growth of diffuse large B-cell lymphoma cell lines

    PubMed Central

    Farina, Floriana Maria; Inguscio, Alessandra; Kunderfranco, Paolo; Cortesi, Alice; Elia, Leonardo; Quintavalle, Manuela

    2017-01-01

    Diffuse large B-cell lymphoma (DLBCL) is the most frequent type of non-Hodgkin lymphoma. Despite a favorable therapeutic response to first-line chemo-immunotherapy, still 30–40% of patients is refractory, or relapse after this treatment. Thus, alternative strategies must be sought. Previous studies have indicated that cyclin-dependent kinase 5 (CDK5), a serine/threonine protein kinase, is involved in tumor development and progression, and it may represent a potential therapeutic target. However, its role in modulating DLBCL growth and progression remains largely unexplored. In this study, we show that CDK5 and its activator, cyclin-dependent kinase 5 activator 1 (CDK5R1 or p35), are overexpressed in DLBCL cell lines and that signal transducer and activator of transcription 3 (STAT3) phosphorylation and activity is dependent on CDK5 expression in DLBCL. Using public data sets, we also demonstrate that patients with DLBCL show a higher expression of CDK5 compared with healthy individuals. By using loss-of-function approaches, we demonstrate that CDK5’s activity regulates proliferation and survival of DLBCL cells. MicroRNAs (miRNAs or miRs) are small noncoding RNAs that negatively regulating gene expression and are involved in cancer initiation and progression. We identify miR-26a as direct regulator of p35 expression and CDK5 activity. We show that miR-26a expression is lower in DLBCL cell lines compared to B lymphocytes and that its ectopic expression leads to a drastic reduction of DLBCL tumor growth in vivo and decreased proliferation, cell-cycle progression, and survival in vitro. Remarkably, concomitant overexpression of a 3′-UTR-truncated form of p35 promoted tumor growth in vivo and cell proliferation, cell-cycle progression, and cell survival in vitro. In conclusion, these results demonstrate an important role for miR-26a and CDK5 together in the survival and growth of DLBCL cells, suggesting the existence of potential novel therapeutic targets for the

  6. Cell division and endoreduplication: doubtful engines of vegetative growth.

    PubMed

    John, Peter C L; Qi, Ruhu

    2008-03-01

    Currently, there is little information to indicate whether plant cell division and development is the collective effect of individual cell programming (cell-based) or is determined by organ-wide growth (organismal). Modulation of cell division does not confirm cell autonomous programming of cell expansion; instead, final cell size seems to be determined by the balance between cells formed and subsequent tissue growth. Control of growth in regions of the plant therefore has great importance in determining cell, organ and plant development. Here, we question the view that formation of new cells and their programmed expansion is the driving force of growth. We believe there is evidence that division does not drive, but requires, cell growth and a similar requirement for growth is detected in the modified cycle termed endoreduplication.

  7. Regulation of mouse thymidylate synthase gene expression in growth-stimulated cells: upstream S phase control elements are indistinguishable from the essential promoter elements.

    PubMed Central

    Ash, J; Liao, W C; Ke, Y; Johnson, L F

    1995-01-01

    Expression of the mammalian thymidylate synthase (TS) gene in growth-stimulated cells is closely coordinated with entry into S phase. Previous studies with transfected TS minigenes have shown that sequences upstream of the coding region as well as an intron in the transcribed region are both necessary for proper regulation of TS mRNA content in growth-stimulated cells. The goal of the present study was to identify the upstream regulatory elements. Minigenes consisting of TS 5' flanking sequences linked to the TS coding region (interrupted by introns 1 and 2) were stably transfected into mouse 3T6 cells. Deletion and site-directed mutagenesis of the 5' flanking region revealed that there is a close correspondence between the upstream sequences that are necessary for S phase regulation and the 30 nucleotide region that is essential for promoter activity. These observations raised the possibility that regulation of the TS gene occurs at the transcriptional level. However, nuclear run-on assays showed that the rate of transcription of the TS gene changed very little during the G1-S phase transition. Furthermore, when the TS promoter was linked to an intron-less luciferase indicator gene, there was no change in expression following growth-stimulation. Therefore it appears that the TS gene is controlled primarily at the posttranscriptional level, and that the TS essential promoter region is necessary (although not sufficient) for proper S phase regulation. Images PMID:8524656

  8. The MexGHI-OpmD multidrug efflux pump controls growth, antibiotic susceptibility and virulence in Pseudomonas aeruginosa via 4-quinolone-dependent cell-to-cell communication.

    PubMed

    Aendekerk, Séverine; Diggle, Stephen P; Song, Zhijun; Høiby, Niels; Cornelis, Pierre; Williams, Paul; Cámara, Miguel

    2005-04-01

    In Pseudomonas aeruginosa the production of multiple virulence factors depends on cell-to-cell communication through the integration of N-acylhomoserine lactone (AHL)- and 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS)- dependent signalling. Mutation of genes encoding the efflux protein MexI and the porin OpmD from the MexGHI-OpmD pump resulted in the inability to produce N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-c12-hsl) and pqs and a marked reduction in n-butanoyl-L-homoserine lactone levels. Both pump mutants were impaired in growth and exhibited enhanced rather than reduced antibiotic resistance. Provision of exogenous PQS improved growth and restored AHL and virulence factor production as well as antibiotic susceptibility, indicating that the pump mutants retained their capacity to respond to PQS. RT-PCR analysis indicated that expression of the PQS biosynthetic genes, phnA and pqsA, was inhibited when the mutants reached stationary phase, suggesting that the pleiotropic phenotype observed may be due to intracellular accumulation of a toxic PQS precursor. To explore this hypothesis, double mexI phnA (unable to produce anthranilate, the precursor of PQS) and mexI pqsA mutants were constructed; the improved growth of the former suggested that the toxic compound is likely to be anthranilate or a metabolite of it. Mutations in mexI and opmD also resulted in the attenuation of virulence in rat and plant infection models. In plants, addition of PQS restored the virulence of mexI and opmD mutants. Collectively, these results demonstrate an essential function for the MexGHI-OpmD pump in facilitating cell-to-cell communication, antibiotic susceptibility and promoting virulence and growth in P. aeruginosa.

  9. Role of bentonite clays on cell growth.

    PubMed

    Cervini-Silva, Javiera; Ramírez-Apan, María Teresa; Kaufhold, Stephan; Ufer, Kristian; Palacios, Eduardo; Montoya, Ascención

    2016-04-01

    Bentonites, naturally occurring clays, are produced industrially because of their adsorbent capacity but little is known about their effects on human health. This manuscript reports on the effect of bentonites on cell growth behaviour. Bentonites collected from India (Bent-India), Hungary (Bent-Hungary), Argentina (Bent-Argentina), and Indonesia (Bent-Indonesia) were studied. All four bentonites were screened in-vitro against two human cancer cell lines [U251 (central nervous system, glioblastoma) and SKLU-1 (lung adenocarcinoma)] supplied by the National Cancer Institute (USA). Bentonites induced growth inhibition in the presence of U251 cells, and growth increment in the presence of SKLU-1 cells, showing that interactions between bentonite and cell surfaces were highly specific. The proliferation response for U251 cells was explained because clay surfaces controlled the levels of metabolic growth components, thereby inhibiting the development of high-grade gliomas, particularly primary glioblastomas. On the other hand, the proliferation response for SKLU-1 was explained by an exacerbated growth favoured by swelling, and concomitant accumulation of solutes, and their hydration and transformation via clay-surface mediated reactions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Fibroblast Growth Factor 2-Mediated Translational Control of IAPs Blocks Mitochondrial Release of Smac/DIABLO and Apoptosis in Small Cell Lung Cancer Cells

    PubMed Central

    Pardo, Olivier E.; Lesay, Adeline; Arcaro, Alexandre; Lopes, Rita; Ng, Bee Ling; Warne, Patricia H.; McNeish, Iain A.; Tetley, Teresa D.; Lemoine, Nicholas R.; Mehmet, Huseyin; Seckl, Michael J.; Downward, Julian

    2003-01-01

    The mitochondrial release of cytochrome c and Smac/DIABLO has been implicated in the activation of apoptosis in response to cell stress. Smac promotes cytochrome c-induced activation of caspases by sequestering the inhibitor of apoptosis protein (IAP) family of potent caspase suppressors. Differential release from mitochondria of cytochrome c and Smac can occur, but the underlying mechanism and physiological significance of this are unclear. Here we show that the mechanism by which fibroblast growth factor 2 (FGF-2) protects small cell lung cancer (SCLC) cells from etoposide-induced cell death involves inhibition of Smac release but not of cytochrome c release. This process is MEK dependent and correlates with an increased expression of XIAP and cellular IAP-1, mediated principally through translational regulation. Exogenous expression of XIAP is sufficient to inhibit caspase 9 activation, Smac release, and cell death induced by etoposide. Prevention of the FGF-2-promoted increase in levels of functional IAPs by RNA interference or the cell-permeant Smac amino-terminal peptide blocked FGF-2-induced protection. FGF-2 can thus protect SCLC cells from chemotherapeutic drugs by modulating IAP levels via posttranscriptional regulation, providing a mechanism for postmitochondrial survival signaling by the MEK/mitogen-activated protein kinase pathway. PMID:14560006

  11. The pituitary growth hormone cell in space

    NASA Technical Reports Server (NTRS)

    Hymer, Wesley C.; Grindeland, R.

    1989-01-01

    Growth hormone (GH), produced and secreted from specialized cells in the pituitary gland, controls the metabolism of protein, fat, and carbohydrate. It is also probably involved in the regulation of proper function of bone, muscle and immune systems. The behavior of the GH cell system was studied by flying either isolated pituitary cells or live rats. In the latter case, pituitary GH cells are prepared on return to earth and then either transplanted into hypophysectomized rats or placed into cell culture so that function of GH cells in-vivo vs. in-vitro can be compared. The results from three flights to date (STS-8, 1983; SL-3, 1985; Cosmos 1887, 1987) established that the ability of GH cells to release hormone, on return to earth, is compromised. The mechanism(s) responsible for this attenuation response is unknown. However, the data are sufficiently positive to indicate that the nature of the secretory defect resides directly within the GH cells.

  12. Controlled Dual Growth Factor Delivery From Microparticles Incorporated Within Human Bone Marrow-Derived Mesenchymal Stem Cell Aggregates for Enhanced Bone Tissue Engineering via Endochondral Ossification

    PubMed Central

    Dang, Phuong N.; Dwivedi, Neha; Phillips, Lauren M.; Yu, Xiaohua; Herberg, Samuel; Bowerman, Caitlin; Solorio, Loran D.; Murphy, William L.

    2016-01-01

    Bone tissue engineering via endochondral ossification has been explored by chondrogenically priming cells using soluble mediators for at least 3 weeks to produce a hypertrophic cartilage template. Although recapitulation of endochondral ossification has been achieved, long-term in vitro culture is required for priming cells through repeated supplementation of inductive factors in the media. To address this challenge, a microparticle-based growth factor delivery system was engineered to drive endochondral ossification within human bone marrow-derived mesenchymal stem cell (hMSC) aggregates. Sequential exogenous presentation of soluble transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2) at various defined time courses resulted in varying degrees of chondrogenesis and osteogenesis as demonstrated by glycosaminoglycan and calcium content. The time course that best induced endochondral ossification was used to guide the development of the microparticle-based controlled delivery system for TGF-β1 and BMP-2. Gelatin microparticles capable of relatively rapid release of TGF-β1 and mineral-coated hydroxyapatite microparticles permitting more sustained release of BMP-2 were then incorporated within hMSC aggregates and cultured for 5 weeks following the predetermined time course for sequential presentation of bioactive signals. Compared with cell-only aggregates treated with exogenous growth factors, aggregates with incorporated TGF-β1- and BMP-2-loaded microparticles exhibited enhanced chondrogenesis and alkaline phosphatase activity at week 2 and a greater degree of mineralization by week 5. Staining for types I and II collagen, osteopontin, and osteocalcin revealed the presence of cartilage and bone. This microparticle-incorporated system has potential as a readily implantable therapy for healing bone defects without the need for long-term in vitro chondrogenic priming. Significance This study demonstrates the regulation of chondrogenesis

  13. Controlled Dual Growth Factor Delivery From Microparticles Incorporated Within Human Bone Marrow-Derived Mesenchymal Stem Cell Aggregates for Enhanced Bone Tissue Engineering via Endochondral Ossification.

    PubMed

    Dang, Phuong N; Dwivedi, Neha; Phillips, Lauren M; Yu, Xiaohua; Herberg, Samuel; Bowerman, Caitlin; Solorio, Loran D; Murphy, William L; Alsberg, Eben

    2016-02-01

    Bone tissue engineering via endochondral ossification has been explored by chondrogenically priming cells using soluble mediators for at least 3 weeks to produce a hypertrophic cartilage template. Although recapitulation of endochondral ossification has been achieved, long-term in vitro culture is required for priming cells through repeated supplementation of inductive factors in the media. To address this challenge, a microparticle-based growth factor delivery system was engineered to drive endochondral ossification within human bone marrow-derived mesenchymal stem cell (hMSC) aggregates. Sequential exogenous presentation of soluble transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2) at various defined time courses resulted in varying degrees of chondrogenesis and osteogenesis as demonstrated by glycosaminoglycan and calcium content. The time course that best induced endochondral ossification was used to guide the development of the microparticle-based controlled delivery system for TGF-β1 and BMP-2. Gelatin microparticles capable of relatively rapid release of TGF-β1 and mineral-coated hydroxyapatite microparticles permitting more sustained release of BMP-2 were then incorporated within hMSC aggregates and cultured for 5 weeks following the predetermined time course for sequential presentation of bioactive signals. Compared with cell-only aggregates treated with exogenous growth factors, aggregates with incorporated TGF-β1- and BMP-2-loaded microparticles exhibited enhanced chondrogenesis and alkaline phosphatase activity at week 2 and a greater degree of mineralization by week 5. Staining for types I and II collagen, osteopontin, and osteocalcin revealed the presence of cartilage and bone. This microparticle-incorporated system has potential as a readily implantable therapy for healing bone defects without the need for long-term in vitro chondrogenic priming. Significance: This study demonstrates the regulation of chondrogenesis

  14. Cell Size Control in Bacteria

    PubMed Central

    Chien, An-Chun; Hill, Norbert S.; Levin, Petra Anne

    2012-01-01

    Like eukaryotes, bacteria must coordinate division with growth to ensure cells are the appropriate size for a given environmental condition or developmental fate. As single-celled organisms, nutrient availability is one of the strongest influences on bacterial cell size. Classic physiological experiments conducted over four decades ago first demonstrated that cell size is directly correlated with nutrient source and growth rate in the Gram-negative bacterium Salmonella typhimurium. This observation subsequently served as the basis for studies revealing a role for cell size in cell cycle progression in a closely related organism, Escherichia coli. More recently, the development of powerful genetic, molecular, and imaging tools has allowed us to identify and characterize the nutrient-dependent pathway responsible for coordinating cell division and cell size with growth rate in the Gram-positive model organism B. subtilis. Here, we discuss the role of cell size in bacterial growth and development and propose a broadly applicable model for cell size control in this important and highly divergent domain of life. PMID:22575476

  15. Leptin Enhances Cholangiocarcinoma Cell Growth

    PubMed Central

    Fava, Giammarco; Alpini, Gianfranco; Rychlicki, Chiara; Saccomanno, Stefania; DeMorrow, Sharon; Trozzi, Luciano; Candelaresi, Cinzia; Venter, Julie; Di Sario, Antonio; Marzioni, Marco; Bearzi, Italo; Glaser, Shannon; Alvaro, Domenico; Marucci, Luca; Francis, Heather; Svegliati-Baroni, Gianluca; Benedetti, Antonio

    2008-01-01

    Cholangiocarcinoma is a strongly aggressive malignancy with a very poor prognosis. Effective therapeutic strategies are lacking because molecular mechanisms regulating cholangiocarcinoma cell growth are unknown. Furthermore, experimental in vivo animal models useful to study the pathophysiologic mechanisms of malignant cholangiocytes are lacking. Leptin, the hormone regulating caloric homeostasis, which is increased in obese patients, stimulates the growth of several cancers, such as hepatocellular carcinoma. The aim of this study was to define if leptin stimulates cholangiocarcinoma growth. We determined the expression of leptin receptors in normal and malignant human cholangiocytes. Effects on intrahepatic cholangiocarcinoma (HuH-28) cell proliferation, migration, and apoptosis of the in vitro exposure to leptin, together with the intracellular pathways, were then studied. Moreover, cholangiocarcinoma was experimentally induced in obese fa/fa Zucker rats, a genetically established animal species with faulty leptin receptors, and in their littermates by chronic feeding with thioacetamide, a potent carcinogen. After 24 weeks, the effect of leptin on cholangiocarcinoma development and growth was assessed. Normal and malignant human cholangiocytes express leptin receptors. Leptin increased the proliferation and the metastatic potential of cholangiocarcinoma cells in vitro through a signal transducers and activators of transcription 3–dependent activation of extracellular signal-regulated kinase 1/2. Leptin increased the growth and migration, and was antiapoptotic for cholangiocarcinoma cells. Moreover, the loss of leptin function reduced the development and the growth of cholangiocarcinoma. The experimental carcinogenesis model induced by thioacetamide administration is a valid and reproducible method to study cholangiocarcinoma pathobiology. Modulation of the leptin-mediated signal could be considered a valid tool for the prevention and treatment of

  16. Energy controllable steep pulse (ECSP) treatment suppresses tumor growth in rats implanted with Walker 256 carcinosarcoma cells through apoptosis and an antitumor immune response.

    PubMed

    Luo, Xiao-Dong; Sun, Jiang-chuan; Liu, Feng; Hu, Li-Na; Dong, Xiao-Jing; Sun, Di-Na; Xiao, Jin

    2012-01-01

    Electrochemotherapy has been widely used for the treatment of solid tumors, although the underlying mechanism remains unclear. We aimed to investigate the effects of energy controllable steep pulse (ECSP) on the regulation of tumor growth and apoptosis in rats implanted with Walker 256 carcinosarcoma cells. A rat tumor model was established by injection of Walker 256 carcinosarcoma cells into the inguinal area. H&E staining, transmission electron microscopy, and the TUNEL assay were used to detect apoptosis. Concanavalin A-induced lymphocyte transformation and MTT assays were used to assess lymphocyte proliferation. ELISA was used to determine serum cytokine levels. After 2 weeks of ECSP treatment, tumor growth in rats was effectively suppressed, while tumor cell apoptosis was significantly induced compared to the control tumor group. Moreover, ECSP treatment enhanced proliferation and activation of lymphocytes and natural killer (NK) cells. Serum IL-2 and IFN-gamma levels were significantly decreased, and IL-4 and 1-10 levels dramatically increased in rats with control tumors compared to rats without tumors and lacking treatment (p < 0.05). In contrast, ECSP treatment increased IL-2 and IFN-gamma levels, but reduced IL-4 and IL-10 levels to normal values. Moreover, ECSP also increased TNF-alpha production, possibly from peritoneal microphages. Our current study demonstrates that ECSP treatment is able to effectively reduce tumors in rats via induction of apoptosis and activation of the rat antitumor immune response. These data provide insightful information for the future application of ECSP-based electrochemotherapy in clinical trials against solid tumors.

  17. Generating controlled reducing environments in aerobic recombinant Escherichia coli fermentations: effects on cell growth, oxygen uptake, heat shock protein expression, and in vivo CAT activity.

    PubMed

    Gill, R T; Cha, H J; Jain, A; Rao, G; Bentley, W E

    1998-07-20

    The independent control of culture redox potential (CRP) by the regulated addition of a reducing agent, dithiothreitol (DTT) was demonstrated in aerated recombinant Escherichia coli fermentations. Moderate levels of DTT addition resulted in minimal changes to specific oxygen uptake, growth rate, and dissolved oxygen. Excessive levels of DTT addition were toxic to the cells resulting in cessation of growth. Chloramphenicol acetyltransferase (CAT) activity (nmoles/microgram total protein min.) decreased in batch fermentation experiments with respect to increasing levels of DTT addition. To further investigate the mechanisms affecting CAT activity, experiments were performed to assay heat shock protein expression and specific CAT activity (nmoles/microgram CAT min.). Expression of such molecular chaperones as GroEL and DnaK were found to increase after addition of DTT. Additionally, sigma factor 32 (sigma32) and several proteases were seen to increase dramatically during addition of DTT. Specific CAT activity (nmoles/microgram CAT min. ) varied greatly as DTT was added, however, a minimum in activity was found at the highest level of DTT addition in E. coli strains RR1 [pBR329] and JM105 [pROEX-CAT]. In conjunction, cellular stress was found to reach a maximum at the same levels of DTT. Although DTT addition has the potential for directly affecting intracellular protein folding, the effects felt from the increased stress within the cell are likely the dominant effector. That the effects of DTT were measured within the cytoplasm of the cell suggests that the periplasmic redox potential was also altered. The changes in specific CAT activity, molecular chaperones, and other heat shock proteins, in the presence of minimal growth rate and oxygen uptake alterations, suggest that the ex vivo control of redox potential provides a new process for affecting the yield and conformation of heterologous proteins in aerated E. coli fermentations.

  18. Comparison of the Effects of PRKAR1A and PRKAR2B Depletion on Signaling Pathways, Cell Growth, and Cell Cycle Control of Adrenocortical Cells

    PubMed Central

    Basso, F.; Rocchetti, F.; Rodriguez, S.; Nesterova, M.; Cormier, F.; Stratakis, C.; Ragazzon, B.; Bertherat, J.; Rizk-Rabin, M.

    2016-01-01

    The cyclic AMP/protein kinase A signaling cascade is one of the main pathways involved in the pathogenesis of adrenocortical tumors. The PKA R1A and R2B proteins are the most abundant regulatory subunits in endocrine tissues. Inactivating mutations of PRKAR1A are associated with Carney complex and a subset of sporadic tumors and the abundance of R2B protein is low in a subset of secreting adrenocortical adenomas. We previously showed that PRKAR1A and PRKAR2B inactivation have anti-apoptotic effects on the adrenocortical carcinoma cell line H295R. The aim of this study was to compare the effects of PRKAR1A and PRKAR2B depletion on cell proliferation, apoptosis, cell signaling pathways, and cell cycle regulation. We found that PRKAR2B depletion is compensated by an upregulation in the abundance of R1A protein, whereas PRKAR1A depletion has no effect on the production of R2B. The depletion of either PRKAR1A or PRKAR2B promotes the expression of Bcl-xL and resistance to apoptosis; and is associated with a high percentage of cells in S and G2 phase, activates PKA and MEK/ERK pathways, and impairs the expression of IkB leading to activate the NF-κB pathway. Nonetheless, we observed differences in the regulation of cyclins. The depletion of PRKAR1A leads to the accumulation of cyclin D1 and p27kip, whereas the depletion of PRKAR2B promotes the accumulation of cyclin A, B, cdk1, cdc2, and p21Cip. In conclusion, although the depletion of PRKAR1A and PRKAR2B in adrenocortical cells has similar effects on cell proliferation and apoptosis; loss of these PKA subunits differentially affects cyclin expression. PMID:25268545

  19. Comparison of the effects of PRKAR1A and PRKAR2B depletion on signaling pathways, cell growth, and cell cycle control of adrenocortical cells.

    PubMed

    Basso, F; Rocchetti, F; Rodriguez, S; Nesterova, M; Cormier, F; Stratakis, C A; Ragazzon, B; Bertherat, J; Rizk-Rabin, M

    2014-11-01

    The cyclic AMP/protein kinase A signaling cascade is one of the main pathways involved in the pathogenesis of adrenocortical tumors. The PKA R1A and R2B proteins are the most abundant regulatory subunits in endocrine tissues. Inactivating mutations of PRKAR1A are associated with Carney complex and a subset of sporadic tumors and the abundance of R2B protein is low in a subset of secreting adrenocortical adenomas. We previously showed that PRKAR1A and PRKAR2B inactivation have anti-apoptotic effects on the adrenocortical carcinoma cell line H295R. The aim of this study was to compare the effects of PRKAR1A and PRKAR2B depletion on cell proliferation, apoptosis, cell signaling pathways, and cell cycle regulation. We found that PRKAR2B depletion is compensated by an upregulation of R1A protein, whereas PRKAR1A depletion has no effect on the production of R2B. The depletion of either PRKAR1A or PRKAR2B promotes the expression of Bcl-xL and resistance to apoptosis; and is associated with a high percentage of cells in S and G2 phase, activates PKA and MEK/ERK pathways, and impairs the expression of IkB leading to activate the NF-κB pathway. However, we observed differences in the regulation of cyclins. The depletion of PRKAR1A leads to the accumulation of cyclin D1 and p27kip, whereas the depletion of PRKAR2B promotes the accumulation of cyclin A, B, cdk1, cdc2, and p21Cip. In conclusion, although the depletion of PRKAR1A and PRKAR2B in adrenocortical cells has similar effects on cell proliferation and apoptosis; loss of these PKA subunits differentially affects cyclin expression. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Single-cell growth analysis in a mixed cell culture

    NASA Astrophysics Data System (ADS)

    Ando, Jun; Bato, Mary Grace P.; Daria, Vincent Ricardo

    2008-06-01

    We perform single cell analysis of cell growth in a mixed cell culture. Two species of yeast cells: Saccharomyces cerevisiae and Candida albicans, are optically trapped using focused continuous-wave near infrared laser. Cell growth for both cells is inhibited only when the two species of cells are in contact with each other. This indicates cell-cell interaction mediated cell growth inhibition mechanism. Single cell level analysis of cell growth studied here contributes to the further understanding of yeast growth arrest in a mixed yeast culture.

  1. Extracellular signal-regulated kinase 2 (ERK-2) mediated phosphorylation regulates nucleo-cytoplasmic shuttling and cell growth control of Ras-associated tumor suppressor protein, RASSF2

    SciTech Connect

    Kumari, Gita; Mahalingam, S.

    2009-10-01

    Ras GTPase controls the normal cell growth through binding with an array of effector molecules, such as Raf and PI3-kinase in a GTP-dependent manner. RASSF2, a member of the Ras association domain family, is known to be involved in the suppression of cell growth and is frequently down-regulated in various tumor tissues by promoter hypermethylation. In the present study, we demonstrate that RASSF2 shuttles between nucleus and cytoplasm by a signal-mediated process and its export from the nucleus is sensitive to leptomycin B. Amino acids between 240 to 260 in the C-terminus of RASSF2 harbor a functional nuclear export signal (NES), which is necessary and sufficient for efficient export of RASSF2 from the nucleus. Substitution of conserved Ile254, Val257 and Leu259 within the minimal NES impaired RASSF2 export from the nucleus. In addition, wild type but not the nuclear export defective RASSF2 mutant interacts with export receptor, CRM-1 and exported from the nucleus. Surprisingly, we observed nucleolar localization for the nuclear export defective mutant suggesting the possibility that RASSF2 may localize in different cellular compartments transiently in a cell cycle dependent manner and the observed nuclear localization for wild type protein may be due to faster export kinetics from the nucleolus. Furthermore, our data suggest that RASSF2 is specifically phosphorylated by MAPK/ERK-2 and the inhibitors of MAPK pathway impair the phosphorylation and subsequently block the export of RASSF2 from the nucleus. These data clearly suggest that ERK-2 mediated phosphorylation plays an important role in regulating the nucleo-cytoplasmic shuttling of RASSF2. Interestingly, nuclear import defective mutant of RASSF2 failed to induce cell cycle arrest at G1/S phase and apoptosis suggesting that RASSF2 regulates cell growth in a nuclear localization dependent manner. Collectively, these data provided evidence for the first time that MAPK/ERK-2 mediated phosphorylation regulates

  2. Designing Neural Networks in Culture: Experiments are described for controlled growth, of nerve cells taken from rats, in predesigned geometrical patterns on laboratory culture dishes.

    PubMed

    Wheeler, Bruce C; Brewer, Gregory J

    2010-03-01

    Technology has advanced to where it is possible to design and grow-with predefined geometry and surprisingly good fidelity-living networks of neurons in culture dishes. Here we overview the elements of design, emphasizing the lithographic techniques that alter the cell culture surface which in turn influences the attachment and growth of the neural networks. Advanced capability in this area makes it possible to design networks of desired complexity. Other issues addressed include the influence of glial cells and media on activity and the potential for extending the designs into three dimensions. Investigators are advancing the art and science of analyzing and controlling through stimulation the function of the neural networks, including the ability to take advantage of their geometric form in order to influence functional properties.

  3. Control of nucleation and growth in protein crystal growth

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz; Meehan, Edward J.

    1988-01-01

    The potential advantages of nucleation and growth control through temperature, rather than the addition of precipitants or removal of solvent, are discussed. A simple light scattering arrangement for the characterization of nucleation and growth conditions in solutions is described. The temperature dependence of the solubility of low ionic strength lysozyme solutions is applied in preliminary nucleation and growth experiments.

  4. Cellular and Tumor Radiosensitivity is Correlated to Epidermal Growth Factor Receptor Protein Expression Level in Tumors Without EGFR Amplification;Epidermal growth factor receptor; Radiotherapy; Squamous cell carcinoma; Biomarker; Local tumor control

    SciTech Connect

    Kasten-Pisula, Ulla; Saker, Jarob; Eicheler, Wolfgang; Krause, Mechthild; Yaromina, Ala; Meyer-Staeckling, Soenke; Scherkl, Benjamin; Kriegs, Malte; Brandt, Burkhard; Grenman, Reidar; Petersen, Cordula; Baumann, Michael; Dikomey, Ekkehard

    2011-07-15

    Purpose: There is conflicting evidence for whether the expression of epidermal growth factor receptor in human tumors can be used as a marker of radioresponse. Therefore, this association was studied in a systematic manner using squamous cell carcinoma (SCC) cell lines grown as cell cultures and xenografts. Methods and Materials: The study was performed with 24 tumor cell lines of different tumor types, including 10 SCC lines, which were also investigated as xenografts on nude mice. Egfr gene dose and the length of CA-repeats in intron 1 were determined by polymerase chain reaction, protein expression in vitro by Western blot and in vivo by enzyme-linked immunosorbent assay, and radiosensitivity in vitro by colony formation. Data were correlated with previously published tumor control dose 50% data after fractionated irradiation of xenografts of the 10 SCC. Results: EGFR protein expression varies considerably, with most tumor cell lines showing moderate and only few showing pronounced upregulation. EGFR upregulation could only be attributed to massive gene amplification in the latter. In the case of little or no amplification, in vitro EGFR expression correlated with both cellular and tumor radioresponse. In vivo EGFR expression did not show this correlation. Conclusions: Local tumor control after the fractionated irradiation of tumors with little or no gene amplification seems to be dependent on in vitro EGFR via its effect on cellular radiosensitivity.

  5. Using buoyant mass to measure the growth of single cells.

    PubMed

    Godin, Michel; Delgado, Francisco Feijó; Son, Sungmin; Grover, William H; Bryan, Andrea K; Tzur, Amit; Jorgensen, Paul; Payer, Kris; Grossman, Alan D; Kirschner, Marc W; Manalis, Scott R

    2010-05-01

    We used a suspended microchannel resonator (SMR) combined with picoliter-scale microfluidic control to measure buoyant mass and determine the 'instantaneous' growth rates of individual cells. The SMR measures mass with femtogram precision, allowing rapid determination of the growth rate in a fraction of a complete cell cycle. We found that for individual cells of Bacillus subtilis, Escherichia coli, Saccharomyces cerevisiae and mouse lymphoblasts, heavier cells grew faster than lighter cells.

  6. Inferring the Impact of Regulatory Mechanisms that Underpin CD8+ T Cell Control of B16 Tumor Growth In vivo Using Mechanistic Models and Simulation

    PubMed Central

    Klinke, David J.; Wang, Qing

    2017-01-01

    A major barrier for broadening the efficacy of immunotherapies for cancer is identifying key mechanisms that limit the efficacy of tumor infiltrating lymphocytes. Yet, identifying these mechanisms using human samples and mouse models for cancer remains a challenge. While interactions between cancer and the immune system are dynamic and non-linear, identifying the relative roles that biological components play in regulating anti-tumor immunity commonly relies on human intuition alone, which can be limited by cognitive biases. To assist natural intuition, modeling and simulation play an emerging role in identifying therapeutic mechanisms. To illustrate the approach, we developed a multi-scale mechanistic model to describe the control of tumor growth by a primary response of CD8+ T cells against defined tumor antigens using the B16 C57Bl/6 mouse model for malignant melanoma. The mechanistic model was calibrated to data obtained following adenovirus-based immunization and validated to data obtained following adoptive transfer of transgenic CD8+ T cells. More importantly, we use simulation to test whether the postulated network topology, that is the modeled biological components and their associated interactions, is sufficient to capture the observed anti-tumor immune response. Given the available data, the simulation results also provided a statistical basis for quantifying the relative importance of different mechanisms that underpin CD8+ T cell control of B16F10 growth. By identifying conditions where the postulated network topology is incomplete, we illustrate how this approach can be used as part of an iterative design-build-test cycle to expand the predictive power of the model. PMID:28101055

  7. UTP Controls Cell Surface Distribution and Vasomotor Activity of the Human P2Y2 Receptor through an Epidermal Growth Factor Receptor-transregulated Mechanism*

    PubMed Central

    Norambuena, Andrés; Palma, Francisco; Poblete, M. Inés; Donoso, M. Verónica; Pardo, Evelyn; González, Alfonso; Huidobro-Toro, J. Pablo

    2010-01-01

    Extracellular nucleotides transmit signals into the cells through the P2 family of cell surface receptors. These receptors are amply expressed in human blood vessels and participate in vascular tone control; however, their signaling mechanisms remain unknown. Here we show that in smooth muscle cells of isolated human chorionic arteries, the activation of the P2Y2 receptor (P2Y2R) induces not only its partition into membrane rafts but also its rapid internalization. Cholesterol depletion with methyl-β-cyclodextrin reduced the association of the agonist-activated receptor into membrane rafts but did not affect either the UTP-mediated vasoconstrictions or the vasomotor responses elicited by both serotonin and KCl. Ex vivo perfusion of human chorionic artery segments with 1–10 μm UTP, a selective P2Y2R agonist, displaced the P2Y2R localization into membrane rafts within 1 min, a process preceded by the activation of both RhoA and Rac1 GTPases. AG1478, a selective and potent inhibitor of the epidermal growth factor receptor tyrosine kinase activity, not only blocked the UTP-induced vasomotor activity but also abrogated both RhoA and Rac1 activation, the P2Y2R association with membrane rafts, and its internalization. Altogether, these results show for the first time that the plasma membrane distribution of the P2Y2R is transregulated by the epidermal growth factor receptor, revealing an unsuspected functional interplay that controls both the membrane distribution and the vasomotor activity of the P2Y2R in intact human blood vessels. PMID:19996104

  8. Inferring the Impact of Regulatory Mechanisms that Underpin CD8+ T Cell Control of B16 Tumor Growth In vivo Using Mechanistic Models and Simulation.

    PubMed

    Klinke, David J; Wang, Qing

    2016-01-01

    A major barrier for broadening the efficacy of immunotherapies for cancer is identifying key mechanisms that limit the efficacy of tumor infiltrating lymphocytes. Yet, identifying these mechanisms using human samples and mouse models for cancer remains a challenge. While interactions between cancer and the immune system are dynamic and non-linear, identifying the relative roles that biological components play in regulating anti-tumor immunity commonly relies on human intuition alone, which can be limited by cognitive biases. To assist natural intuition, modeling and simulation play an emerging role in identifying therapeutic mechanisms. To illustrate the approach, we developed a multi-scale mechanistic model to describe the control of tumor growth by a primary response of CD8+ T cells against defined tumor antigens using the B16 C57Bl/6 mouse model for malignant melanoma. The mechanistic model was calibrated to data obtained following adenovirus-based immunization and validated to data obtained following adoptive transfer of transgenic CD8+ T cells. More importantly, we use simulation to test whether the postulated network topology, that is the modeled biological components and their associated interactions, is sufficient to capture the observed anti-tumor immune response. Given the available data, the simulation results also provided a statistical basis for quantifying the relative importance of different mechanisms that underpin CD8+ T cell control of B16F10 growth. By identifying conditions where the postulated network topology is incomplete, we illustrate how this approach can be used as part of an iterative design-build-test cycle to expand the predictive power of the model.

  9. The cell biology of bone growth.

    PubMed

    Price, J S; Oyajobi, B O; Russell, R G

    1994-02-01

    The field of bone cell biology is clearly of relevance to the problem of stunting in children, as in the final analysis the cells of the growing long bone are the ultimate 'regulators'. It is the alterations in the functions of these cells that manifests as a reduction in height. Normal longitudinal growth is achieved by the coordinated recruitment, proliferation, differentiation, maturation and eventual death of the cells of growth plate and bone. Cellular activity is closely regulated by endocrine factors acting directly or indirectly, with factors produced locally and stored within the bone and cartilage microenvironment having a critical role in intercellular communication. Disruption of any of these processes can lead to growth disturbances, since it only requires a defect in a single gene to have profound effects. Studies in recent years have shed light on the biochemical and molecular effects of cytokines and growth factors and have shown that these regulatory molecules may mediate the effects of certain hormones important in controlling growth. However, the complex interrelationship of these molecules is still not clear. Notwithstanding, understanding of the mechanisms involved in bone remodelling is increasing, as this area attracts much research because of the high incidence of metabolic bone disease in Western society. Although studies of adult bone remodelling are of relevance, there is a requirement for increased research directed specifically at the mechanisms of endochondral ossification and its regulation. Longitudinal bone growth is a challenge to the cell biologist, since it is an accelerated cycle of cellular division and differentiation, within which it is not easy to separate events temporally and spatially. In addition, different regulatory mechanisms are probably important at different stages of growth. Another difficulty impeding progress in this field is the lack of appropriate animal models for research. Much information has come from

  10. Dynamic changes in the osteoclast cytoskeleton in response to growth factors and cell attachment are controlled by beta3 integrin.

    PubMed

    Faccio, Roberta; Novack, Deborah V; Zallone, Alberta; Ross, F Patrick; Teitelbaum, Steven L

    2003-08-04

    The beta3 integrin cytoplasmic domain, and specifically S752, is critical for integrin localization and osteoclast (OC) function. Because growth factors such as macrophage colony-stimulating factor and hepatocyte growth factor affect integrin activation and function via inside-out signaling, a process requiring the beta integrin cytoplasmic tail, we examined the effect of these growth factors on OC precursors. To this end, we retrovirally expressed various beta3 integrins with cytoplasmic tail mutations in beta3-deficient OC precursors. We find that S752 in the beta3 cytoplasmic tail is required for growth factor-induced integrin activation, cytoskeletal reorganization, and membrane protrusion, thereby affecting OC adhesion, migration, and bone resorption. The small GTPases Rho and Rac mediate cytoskeletal reorganization, and activation of each is defective in OC precursors lacking a functional beta3 subunit. Activation of the upstream mediators c-Src and c-Cbl is also dependent on beta3. Interestingly, although the FAK-related kinase Pyk2 interacts with c-Src and c-Cbl, its activation is not disrupted in the absence of functional beta3. Instead, its activation is dependent upon intracellular calcium, and on the beta2 integrin. Thus, the beta3 cytoplasmic domain is responsible for activation of specific intracellular signals leading to cytoskeletal reorganization critical for OC function.

  11. Effect of the antioxidant ionol (BHT) on growth and development of etiolated wheat seedlings: control of apoptosis, cell division, organelle ultrastructure, and plastid differentiation.

    PubMed

    Bakeeva, L E; Zamyatnina, V A; Shorning, B Y; Aleksandrushkina, N I; Vanyushin, B F

    2001-08-01

    Ionol (BHT), a compound having antioxidant activity, at concentrations in the range 1-50 mg/liter (0.45 x 10(-5)-2.27 x 10(-4) M), inhibits growth of etiolated wheat seedlings, changes the morphology of their organs, prolongs the coleoptile life span, and prevents the appearance of specific features of aging and apoptosis in plants. In particular, BHT prevents the age-dependent decrease in total DNA content, apoptotic internucleosomal fragmentation of nuclear DNA, appearance in the cell vacuole of specific vesicles with active mitochondria intensively producing mtDNA, and formation of heavy mitochondrial DNA rho = 1.718 g/cm3) in coleoptiles of etiolated wheat seedlings. BHT induces large structural changes in the organization of all cellular organelles (nucleus, mitochondria, plastids, Golgi apparatus, endocytoplasmic reticulum) and the formation of new unusual membrane structures in the cytoplasm. BHT distorts the division of nuclei and cells, and this results in the appearance of multi-bladed polyploid nuclei and multinuclear cells. In roots of etiolated wheat seedlings, BHT induces intensive synthesis of pigments, presumably carotenoids, and the differentiation of plastids with formation of chloro- or chromoplasts. The observed multiple effects of BHT are due to its antioxidative properties (the structural BHT analog 3,5-di-tert-butyltoluene is physiologically inert; it has no effect similar to that of BHT). Therefore, the reactive oxygen species (ROS) controlled by BHT seem to trigger apoptosis and the structural reorganization of the cytoplasm in the apoptotic cell with formation of specific vacuolar vesicles that contain active mitochondria intensively producing mtDNA. Thus, the inactivation of ROS by BHT may be responsible for the observed changes in the structure of all the mentioned cellular organelles. This corresponds to the idea that ROS control apoptosis and mitosis including formation of cell wall, and they are powerful secondary messengers that

  12. Organelle growth control through limiting pools of cytoplasmic components.

    PubMed

    Goehring, Nathan W; Hyman, Anthony A

    2012-05-08

    The critical importance of controlling the size and number of intracellular organelles has led to a variety of mechanisms for regulating the formation and growth of cellular structures. In this review, we explore a class of mechanisms for organelle growth control that rely primarily on the cytoplasm as a 'limiting pool' of available material. These mechanisms are based on the idea that, as organelles grow, they incorporate subunits from the cytoplasm. If this subunit pool is limited, organelle growth will lead to depletion of subunits from the cytoplasm. Free subunit concentration therefore provides a measure of the number of incorporated subunits and thus the current size of the organelle. Because organelle growth rates are typically a function of subunit concentration, cytoplasmic depletion links organelle size, free subunit concentration, and growth rates, ensuring that as the organelle grows, its rate of growth slows. Thus, a limiting cytoplasmic pool provides a powerful mechanism for size-dependent regulation of growth without recourse to active mechanisms to measure size or modulate growth rates. Variations of this general idea allow not only for size control, but also cell-size-dependent scaling of cellular structures, coordination of growth between similar structures within a cell, and the enforcement of singularity in structure formation, when only a single copy of a structure is desired. Here, we review several examples of such mechanisms in cellular processes as diverse as centriole duplication, centrosome and nuclear size control, cell polarity, and growth of flagella. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Bone Morphogenetic Protein and Activin Membrane-Bound Inhibitor, a Transforming Growth Factor β Rheostat That Controls Murine Treg Cell/Th17 Cell Differentiation and the Development of Autoimmune Arthritis by Reducing Interleukin-2 Signaling.

    PubMed

    Postigo, Jorge; Iglesias, Marcos; Álvarez, Pilar; Jesús Augustin, Juan; Buelta, Luis; Merino, Jesús; Merino, Ramón

    2016-06-01

    Transforming growth factor β (TGFβ) plays a prominent role in the establishment of immunologic tolerance, and mice lacking TGFβ1 die of multiorgan inflammation early in life. TGFβ controls the differentiation of CD4+ lymphocytes into Treg cells or proinflammatory Th17 cells. Although this dual capacity is modulated by the presence of additional cytokines around the activated cells, TGFβ also dissociates Th17/Treg cell differentiation in a dose-dependent manner by mechanisms still unknown. The purpose of this study was to explore the contribution of bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) to the modulation of TGFβ activity during the differentiation of CD4+ cells and in the control of immunologic tolerance in mice with collagen-induced arthritis (CIA). The in vitro and in vivo Treg cell and Th17 cell differentiation and the development of CIA were compared in wild-type mice and BAMBI-deficient mice. BAMBI was induced after activation by TGFβ and fixed the appropriate intensity level of TGFβ signaling in CD4+ cells. Its deficiency protected mice against the development of CIA by a Treg cell- and TGFβ-dependent mechanism. Mechanistically, BAMBI was found to regulate CD25 expression and interleukin-2 (IL-2) signaling in Treg cells and in IL-2- and/or TGFβ-activated CD4+ cells and modulated Treg cell and Th17 cell differentiation both in vitro and in vivo. Taken together, the results indicate that BAMBI is a component of a rheostat-like mechanism that, through the control of TGFβ and IL-2 signaling strength, regulates the differentiation of CD4+ lymphocytes and the development of autoimmune arthritis. © 2016, American College of Rheumatology.

  14. The histone deacetylase inhibitor SAHA acts in synergism with fenretinide and doxorubicin to control growth of rhabdoid tumor cells.

    PubMed

    Kerl, Kornelius; Ries, David; Unland, Rebecca; Borchert, Christiane; Moreno, Natalia; Hasselblatt, Martin; Jürgens, Heribert; Kool, Marcel; Görlich, Dennis; Eveslage, Maria; Jung, Manfred; Meisterernst, Michael; Frühwald, Michael

    2013-06-13

    Rhabdoid tumors are highly aggressive malignancies affecting infants and very young children. In many instances these tumors are resistant to conventional type chemotherapy necessitating alternative approaches. Proliferation assays (MTT), apoptosis (propidium iodide/annexin V) and cell cycle analysis (DAPI), RNA expression microarrays and western blots were used to identify synergism of the HDAC (histone deacetylase) inhibitor SAHA with fenretinide, tamoxifen and doxorubicin in rhabdoidtumor cell lines. HDAC1 and HDAC2 are overexpressed in primary rhabdoid tumors and rhabdoid tumor cell lines. Targeting HDACs in rhabdoid tumors induces cell cycle arrest and apoptosis. On the other hand HDAC inhibition induces deregulated gene programs (MYCC-, RB program and the stem cell program) in rhabdoid tumors. These programs are in general associated with cell cycle progression. Targeting these activated pro-proliferative genes by combined approaches of HDAC-inhibitors plus fenretinide, which inhibits cyclinD1, exhibit strong synergistic effects on induction of apoptosis. Furthermore, HDAC inhibition sensitizes rhabdoid tumor cell lines to cell death induced by chemotherapy. Our data demonstrate that HDAC inhibitor treatment in combination with fenretinide or conventional chemotherapy is a promising tool for the treatment of chemoresistant rhabdoid tumors.

  15. Proepithelin Regulates Prostate Cancer Cell Biology by Promoting Cell Growth, Migration, and Anchorage-Independent Growth

    PubMed Central

    Monami, Giada; Emiliozzi, Velia; Bitto, Alessandro; Lovat, Francesca; Xu, Shi-Qiong; Goldoni, Silvia; Fassan, Matteo; Serrero, Ginette; Gomella, Leonard G.; Baffa, Raffaele; Iozzo, Renato V.; Morrione, Andrea

    2009-01-01

    The growth factor proepithelin has recently emerged as an important regulator of transformation in several physiological and pathological systems. In this study, we determined the biological roles of proepithelin in prostate cancer cells using purified human recombinant proepithelin as well as proepithelin-depletion strategies. Proepithelin promoted the migration of androgen-dependent and -independent human prostate cancer cells; androgen-independent DU145 cells were the more responsive. In these cells, proepithelin additionally stimulated wound closure, invasion, and promotion of cell growth in vitro. These effects required the activation of both the Akt and mitogen-activated protein kinase pathways. We have analyzed proepithelin expression levels in different available prostate cancer microarray studies using the Oncomine database and found a statistically significant increase in proepithelin mRNA expression levels in prostate cancers compared with nonneoplastic controls. Notably, depletion of endogenous proepithelin by siRNA and antisense strategies impaired the ability of DU145 cells to grow and migrate after serum withdrawal and inhibited anchorage-independent growth. Our results provide the first evidence for a role of proepithelin in stimulating the migration, invasion, proliferation, and anchorage-independent growth of prostate cancer cells. This study supports the hypothesis that proepithelin may play a critical role as an autocrine growth factor in the establishment and initial progression of prostate cancer. Furthermore, proepithelin may prove to be a useful clinical marker for the diagnosis of prostate tumors. PMID:19179604

  16. A New Insulin-Like Growth Factor Binding Protein (mac 25) and Its Role in Breast Cancer and Cell Growth Control

    DTIC Science & Technology

    1997-09-01

    sequence for IGFBP-7 (mac25) by PCR/sequence analysis of cDNA made from five cell lines. Two often clones obtained from a library screening contain...vector is intact and expression is detected. Aim 2: Experiments for promoter studies; library screening and clone analysis. Experimental Methods A human

  17. Purification of kidney epithelial cell growth inhibitors.

    PubMed Central

    Holley, R W; Böhlen, P; Fava, R; Baldwin, J H; Kleeman, G; Armour, R

    1980-01-01

    Two high molecular weight growth inhibitors have been isolated from the culture medium of BSC-1 cells, epithelial cells of African green monkey kidney. The purified kidney epithelial cell growth inhibitors, at ng/ml concentrations, reversibly arrest the growth of BSC-1 cells in the G1 phase of the cell cycle. Their action is selective; they are most active on BSC-1 cells, are less active as inhibitors of the growth of rat lung and human breast epithelial cells, and do not inhibit the growth of 3T3 mouse embryo fibroblasts ad human skin fibroblasts in culture. Their growth inhibitory action on BSC-1 cell cultures is counteracted by epidermal growth factor or calf serum. PMID:6969400

  18. Growth of CH3NH3PbI3 cuboids with controlled size for high-efficiency perovskite solar cells.

    PubMed

    Im, Jeong-Hyeok; Jang, In-Hyuk; Pellet, Norman; Grätzel, Michael; Park, Nam-Gyu

    2014-11-01

    Perovskite solar cells with submicrometre-thick CH(3)NH(3)PbI(3) or CH(3)NH(3)PbI(3-x)Cl(x) active layers show a power conversion efficiency as high as 15%. However, compared to the best-performing device, the average efficiency was as low as 12%, with a large standard deviation (s.d.). Here, we report perovskite solar cells with an average efficiency exceeding 16% and best efficiency of 17%. This was enabled by the growth of CH(3)NH(3)PbI(3) cuboids with a controlled size via a two-step spin-coating procedure. Spin-coating of a solution of CH(3)NH(3)I with different concentrations follows the spin-coating of PbI(2), and the cuboid size of CH(3)NH(3)PbI(3) is found to strongly depend on the concentration of CH(3)NH(3)I. Light-harvesting efficiency and charge-carrier extraction are significantly affected by the cuboid size. Under simulated one-sun illumination, average efficiencies of 16.4% (s.d. ± 0.35), 16.3% (s.d. ± 0.44) and 13.5% (s.d. ± 0.34) are obtained from solutions of CH(3)NH(3)I with concentrations of 0.038 M, 0.050 M and 0.063 M, respectively. By controlling the size of the cuboids of CH(3)NH(3)PbI(3) during their growth, we achieved the best efficiency of 17.01% with a photocurrent density of 21.64 mA cm(-2), open-circuit photovoltage of 1.056 V and fill factor of 0.741.

  19. [Micro/nano-engineering to control growth of neuronal cells and tissue engineering applied to the central nervous system].

    PubMed

    Béduer, Amélie; Vaysse, Laurence; Loubinoux, Isabelle; Vieu, Christophe

    2013-01-01

    Central nervous system pathologies are often characterized by the loss of cell populations. A promising therapy now being developed consists in using bioactive materials, associating grafted cells to biopolymers which provide a scaffold for the in vitro building of new tissues, to be implanted in vivo. In the present article, the state of the art of this field, at crossroads between microtechnology and neuroscience, is described in detail; thereafter our own approach and results about interactions between adult human neural stem cells and microstructured polymers are summarized and discussed. In a second part, some central nervous system repair strategies, based on cerebral tissue engineering, are presented. We will report the main results of our studies to work out and characterize in vivo a cerebral bioprosthesis. © Société de Biologie, 2014.

  20. Automated single cell microbioreactor for monitoring intracellular dynamics and cell growth in free solution†

    PubMed Central

    Johnson-Chavarria, Eric M.; Agrawal, Utsav; Tanyeri, Melikhan; Kuhlman, Thomas E.

    2014-01-01

    We report an automated microfluidic-based platform for single cell analysis that allows for cell culture in free solution with the ability to control the cell growth environment. Using this approach, cells are confined by the sole action of gentle fluid flow, thereby enabling non-perturbative analysis of cell growth away from solid boundaries. In addition, the single cell microbioreactor allows for precise and time-dependent control over cell culture media, with the combined ability to observe the dynamics of non-adherent cells over long time scales. As a proof-of-principle demonstration, we used the platform to observe dynamic cell growth, gene expression, and intracellular diffusion of repressor proteins while precisely tuning the cell growth environment. Overall, this microfluidic approach enables the direct observation of cellular dynamics with exquisite control over environmental conditions, which will be useful for quantifying the behaviour of single cells in well-defined media. PMID:24836754

  1. Elastic Deformations During Bacterial Cell Growth

    NASA Astrophysics Data System (ADS)

    Huang, K. C.

    2010-03-01

    The wide variety of shapes and sizes found in bacterial species is almost universally defined by the cell wall, which is a cross-linked network of the material peptidoglycan. In recent years, cell shape has been shown to play a critical role in regulating many important biological functions including attachment, dispersal, motility, polar differentiation, predation, and cellular differentiation. In previous work, we have shown that the spatial organization of the peptidoglycan network can change the mechanical equilibrium of the cell wall and result in changes in cell shape. However, experimental data on the mechanical properties of peptidoglycan is currently limited. Here, we describe a straightforward, inexpensive approach for extracting the mechanical properties of bacterial cells in gels of user-defined stiffness, using only optical microscopy to match growth kinetics to the predictions of a continuum model of cell growth. Using this simple yet general methodology, we have measured the Young's modulus for bacteria ranging across a wide variety of shapes, sizes, and cell wall thicknesses, and our method can easily be extended to other commonly studied bacteria. This method makes it possible to rapidly determine how changes in genotype and biochemistry affect the mechanical properties of the cell wall, and may be particularly relevant for studying the relationship between cell shape and structure, the genetic and molecular control of the mechanical properties of the cell wall, and the identification of antibiotics and other small molecules that affect and specifically modify the mechanical properties of the cell wall. Our work also suggests that bacteria may utilize peptidoglycan synthesis to transduce mechanosensory signals from local environment.

  2. Dissecting Mannose 6-Phosphate-Insulin-like Growth Factor 2 Receptor Complexes That Control Activation and Uptake of Plasminogen in Cells*

    PubMed Central

    Leksa, Vladimir; Pfisterer, Karin; Ondrovičová, Gabriela; Binder, Brigitte; Lakatošová, Silvia; Donner, Clemens; Schiller, Herbert B.; Zwirzitz, Alexander; Mrvová, Katarína; Pevala, Vladimir; Kutejová, Eva; Stockinger, Hannes

    2012-01-01

    The plasminogen (Plg) activation cascade on the cell surface plays a central role in cell migration and is involved in a plethora of physiological and pathological processes. Its regulation is coordinated by many receptors, in particular the urokinase-type plasminogen activator receptor (uPAR, CD87), receptors that physically interact and functionally cooperate with uPAR, and Plg binding molecules. Here we studied the impact of one of the Plg binding molecules, the mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P-IGF2R, CD222), on cellular Plg activation. By developing both in vitro and in vivo Plg activation assays on size-fractionated lysates of M6P-IGF2R-silenced cells, we identified Plg-associated complexes with M6P-IGF2R as the regulatory factor. Using lipid raft preserving versus dissolving detergents, we found lipid dependence of the Plg regulatory function of these complexes. Furthermore, M6P-IGF2R-silencing in uPAR-positive human cell lines reduced internalization of Plg, resulting in elevated Plg activation. In contrast, the expression of human M6P-IGF2R in mouse embryonic fibroblasts derived from M6P-IGF2R knock-out mice enhanced Plg internalization. Finally, peptide 18–36 derived from the Plg-binding site within M6P-IGF2R enhanced Plg uptake. Thus, by targeting Plg to endocytic pathways, M6P-IGF2R appears to control Plg activation within cells that might be important to restrict plasmin activity to specific sites and substrates. PMID:22613725

  3. Measurement of adherent cell mass and growth

    PubMed Central

    Park, Kidong; Millet, Larry J.; Kim, Namjung; Li, Huan; Jin, Xiaozhong; Popescu, Gabriel; Aluru, N. R.; Hsia, K. Jimmy; Bashir, Rashid

    2010-01-01

    The characterization of physical properties of cells such as their mass and stiffness has been of great interest and can have profound implications in cell biology, tissue engineering, cancer, and disease research. For example, the direct dependence of cell growth rate on cell mass for individual adherent human cells can elucidate the mechanisms underlying cell cycle progression. Here we develop an array of micro-electro-mechanical systems (MEMS) resonant mass sensors that can be used to directly measure the biophysical properties, mass, and growth rate of single adherent cells. Unlike conventional cantilever mass sensors, our sensors retain a uniform mass sensitivity over the cell attachment surface. By measuring the frequency shift of the mass sensors with growing (soft) cells and fixed (stiff) cells, and through analytical modeling, we derive the Young’s modulus of the unfixed cell and unravel the dependence of the cell mass measurement on cell stiffness. Finally, we grew individual cells on the mass sensors and measured their mass for 50+ hours. Our results demonstrate that adherent human colon epithelial cells have increased growth rates with a larger cell mass, and the average growth rate increases linearly with the cell mass, at 3.25%/hr. Our sensitive mass sensors with a position-independent mass sensitivity can be coupled with microscopy for simultaneous monitoring of cell growth and status, and provide an ideal method to study cell growth, cell cycle progression, differentiation, and apoptosis. PMID:21068372

  4. The Systemic Control of Growth.

    PubMed

    Boulan, Laura; Milán, Marco; Léopold, Pierre

    2015-08-10

    Growth is a complex process that is intimately linked to the developmental program to form adults with proper size and proportions. Genetics is an important determinant of growth, as exemplified by the role of local diffusible molecules setting up organ proportions. In addition, organisms use adaptive responses allowing modulating the size of individuals according to environmental cues, for example, nutrition. Here, we describe some of the physiological principles participating in the determination of final individual size.

  5. Computer-controlled float zone crystal growth

    NASA Technical Reports Server (NTRS)

    Chan, Y. T.; Mailloux, P. A.

    1993-01-01

    A PC-based computer control system to automate a high-temperature float zone growth of titanium carbide is reported. The control strategy of the computer control system relies on the relations derived from a combination of empirical relations and results from detailed mathematical analysis of the physical transports of the entire float zone assembly. A system control computer program was written to establish real-time determination of the size of the molten zone from a thermal image, control parameters from established relationships, and collected processed data to achieve control objectives. We found that the developed computer control allows the growth process to be operated nearer the stability limit. Any slight variations in growth conditions can be corrected in time to avoid any instability growth, which otherwise cannot be adjusted via manual control.

  6. Integrated RNA- and protein profiling of fermentation and respiration in diploid budding yeast provides insight into nutrient control of cell growth and development.

    PubMed

    Becker, Emmanuelle; Liu, Yuchen; Lardenois, Aurélie; Walther, Thomas; Horecka, Joe; Stuparevic, Igor; Law, Michael J; Lavigne, Régis; Evrard, Bertrand; Demougin, Philippe; Riffle, Michael; Strich, Randy; Davis, Ronald W; Pineau, Charles; Primig, Michael

    2015-04-24

    Diploid budding yeast undergoes rapid mitosis when it ferments glucose, and in the presence of a non-fermentable carbon source and the absence of a nitrogen source it triggers sporulation. Rich medium with acetate is a commonly used pre-sporulation medium, but our understanding of the molecular events underlying the acetate-driven transition from mitosis to meiosis is still incomplete. We identified 263 proteins for which mRNA and protein synthesis are linked or uncoupled in fermenting and respiring cells. Using motif predictions, interaction data and RNA profiling we find among them 28 likely targets for Ume6, a subunit of the conserved Rpd3/Sin3 histone deacetylase-complex regulating genes involved in metabolism, stress response and meiosis. Finally, we identify 14 genes for which both RNA and proteins are detected exclusively in respiring cells but not in fermenting cells in our sample set, including CSM4, SPR1, SPS4 and RIM4, which were thought to be meiosis-specific. Our work reveals intertwined transcriptional and post-transcriptional control mechanisms acting when a MATa/α strain responds to nutritional signals, and provides molecular clues how the carbon source primes yeast cells for entering meiosis. Our integrated genomics study provides insight into the interplay between the transcriptome and the proteome in diploid yeast cells undergoing vegetative growth in the presence of glucose (fermentation) or acetate (respiration). Furthermore, it reveals novel target genes involved in these processes for Ume6, the DNA binding subunit of the conserved histone deacetylase Rpd3 and the co-repressor Sin3. We have combined data from an RNA profiling experiment using tiling arrays that cover the entire yeast genome, and a large-scale protein detection analysis based on mass spectrometry in diploid MATa/α cells. This distinguishes our study from most others in the field-which investigate haploid yeast strains-because only diploid cells can undergo meiotic development

  7. Rapid control of phase growth by nanoparticles

    PubMed Central

    Chen, Lian-Yi; Xu, Jia-Quan; Choi, Hongseok; Konishi, Hiromi; Jin, Song; Li, Xiao-Chun

    2014-01-01

    Effective control of phase growth under harsh conditions (such as high temperature, highly conductive liquids or high growth rate), where surfactants are unstable or ineffective, is still a long-standing challenge. Here we show a general approach for rapid control of diffusional growth through nanoparticle self-assembly on the fast-growing phase during cooling. After phase nucleation, the nanoparticles spontaneously assemble, within a few milliseconds, as a thin coating on the growing phase to block/limit diffusion, resulting in a uniformly dispersed phase orders of magnitude smaller than samples without nanoparticles. The effectiveness of this approach is demonstrated in both inorganic (immiscible alloy and eutectic alloy) and organic materials. Our approach overcomes the microstructure refinement limit set by the fast phase growth during cooling and breaks the inherent limitations of surfactants for growth control. Considering the growing availability of numerous types and sizes of nanoparticles, the nanoparticle-enabled growth control will find broad applications. PMID:24809454

  8. A MODEL OF GROWTH AND GROWTH CONTROL IN MATHEMATICAL TERMS

    PubMed Central

    Weiss, Paul; Kavanau, J. Lee

    1957-01-01

    A practicable model of the growth process, which gives better definition to the problem of growth and growth regulation and greater precision to related experimental work than do earlier models, is developed on the basis of the following assumptions: "Growth" is the net balance of mass produced and retained over mass destroyed and otherwise lost, implying continual metabolic degradation and replacement. Terminal size represents stationary equilibrium between incremental and decremental components. The mass of an organic system consists of two functionally different components,—generative and differentiated. Generative mass increases by the catalytic action of key compounds ("templates") characteristic of each cell type. Each cell also produces specific freely diffusible compounds antagonistic to these templates ("antitemplates"). Growth regulation occurs automatically by a negative "feedback" in which increasing numbers of antitemplates progressively block the corresponding templates. Differential equations expressing these interrelationships are formulated, integrated, and the solutions evaluated for the case of chick growth. These specific solutions lead to descriptions of the normal growth of a biological system which are in good agreement with known facts, and to predictions of the course of automatic growth regulations after experimental or pathological disturbances which reproduce adequately biological observations in this domain. PMID:13463267

  9. p16 controls epithelial cell growth and suppresses carcinogenesis through mechanisms that do not require RB1 function

    PubMed Central

    Sen, M; Akeno, N; Reece, A; Miller, A L; Simpson, D S; Wikenheiser-Brokamp, K A

    2017-01-01

    The p16/RB1 tumor suppressor pathway is inactivated in the vast majority, if not all, human cancers. The current paradigm is that p16 and RB1 function in a linear pathway to suppress tumorigenesis; however p16 is preferentially lost in human cancers suggesting that p16 has critical tumor suppressive functions not mediated through RB1. Carcinomas arise from transformed epithelial cells and account for 80% of adult malignancies highlighting the need to understand p16/RB1 pathway function in organ epithelia. Lung cancer is the leading cause of cancer deaths and is associated with p16/RB1 pathway deregulation. We demonstrate that p16 is upregulated in the lung epithelium after Rb1 ablation in genetically engineered mouse models. In contrast to fibroblasts, loss of RB1 family proteins, p107 or p130, did not result in p16 induction, demonstrating that p16 suppression is a unique RB1 pocket protein function in the lung epithelium in vivo. p16 upregulation did not induce cellular senescence but rather promoted survival of RB1-deficient lung epithelial progenitor cells. Mechanistic studies show that p16 protects RB1-deficient cells from DNA damage. Consequently, additional loss of p16 led to genetic instability and increased susceptibility to cellular immortalization and transformation. Mice with combined RB1/p16-deficient lungs developed lung tumors including aggressive metastatic lung cancers. These studies identify p16 loss as a molecular event that causes genetic instability and directly demonstrate that p16 protects against DNA damage in the absence of RB1 function providing an explanation for why p16 is preferentially targeted in human cancers. PMID:28414317

  10. p16 controls epithelial cell growth and suppresses carcinogenesis through mechanisms that do not require RB1 function.

    PubMed

    Sen, M; Akeno, N; Reece, A; Miller, A L; Simpson, D S; Wikenheiser-Brokamp, K A

    2017-04-17

    The p16/RB1 tumor suppressor pathway is inactivated in the vast majority, if not all, human cancers. The current paradigm is that p16 and RB1 function in a linear pathway to suppress tumorigenesis; however p16 is preferentially lost in human cancers suggesting that p16 has critical tumor suppressive functions not mediated through RB1. Carcinomas arise from transformed epithelial cells and account for 80% of adult malignancies highlighting the need to understand p16/RB1 pathway function in organ epithelia. Lung cancer is the leading cause of cancer deaths and is associated with p16/RB1 pathway deregulation. We demonstrate that p16 is upregulated in the lung epithelium after Rb1 ablation in genetically engineered mouse models. In contrast to fibroblasts, loss of RB1 family proteins, p107 or p130, did not result in p16 induction, demonstrating that p16 suppression is a unique RB1 pocket protein function in the lung epithelium in vivo. p16 upregulation did not induce cellular senescence but rather promoted survival of RB1-deficient lung epithelial progenitor cells. Mechanistic studies show that p16 protects RB1-deficient cells from DNA damage. Consequently, additional loss of p16 led to genetic instability and increased susceptibility to cellular immortalization and transformation. Mice with combined RB1/p16-deficient lungs developed lung tumors including aggressive metastatic lung cancers. These studies identify p16 loss as a molecular event that causes genetic instability and directly demonstrate that p16 protects against DNA damage in the absence of RB1 function providing an explanation for why p16 is preferentially targeted in human cancers.

  11. Expression and developmental control of platelet-derived growth factor A-chain and B-chain/Sis genes in rat aortic smooth muscle cells

    SciTech Connect

    Majesky, M.W.; Benditt, E.P.; Schwartz, S.M.

    1988-03-01

    Cultured arterial smooth muscle cells (SMC) can produce platelet-derived growth factor (PDGF)-like molecules. This property raises the possibility that SMC-derived PDGFs function as autocrine/paracrine regulators in the formation and maintenance of the artery wall. In this study the authors have asked if levels of mRNAs directing synthesis of PDFG are modulated in aortic SMC during postnatal development. The authors report here that genes encoding PDGF A- and B-chain precursors are expressed at similar low levels in intact aortas from newborn and adult rats. Marked differences in regulation of transcript abundance of these genes were revealed when aortic SMC were grown in cell culture. PDGF B-chain transcripts accumulated in passaged newborn rat SMC but not adult rat SMC, whereas PDGF A-chain RNA was found in comparable amounts in SMC from both age groups. Similarly, SMC from newborn rats secreted at least 60-fold more PDGF-like activity into conditioned medium than did adult rat SMC. These results show that PDGF A- and B-chain genes are transcribed in the normal rat aorta and provide evidence for age-related change in the control of PDGF B-chain gene expression in aortic SMC. Independent regulation of transcript levels in cultured SMC leaves open the possibility that PDGFs of different composition (AA, AB, BB) play different roles in normal function of the artery wall.

  12. Dual regulation of cofilin activity by LIM kinase and Slingshot-1L phosphatase controls platelet-derived growth factor-induced migration of human aortic smooth muscle cells.

    PubMed

    San Martín, Alejandra; Lee, Moo Yeol; Williams, Holly C; Mizuno, Kensaku; Lassègue, Bernard; Griendling, Kathy K

    2008-02-29

    Platelet-derived growth factor (PDGF) plays a central role in vascular healing, atherosclerosis, and restenosis, partly by stimulating vascular smooth muscle cell (VSMC) migration. Migration requires rapid turnover of actin filaments, which is partially controlled by cofilin. Although cofilin is negatively regulated by Ser3 phosphorylation, the upstream signaling pathways have not been defined, nor has its role in VSMC migration been studied. We hypothesized that PDGF-induced migration of VSMCs involves cofilin activation and that this is regulated by the serine kinase LIM kinase (LIMK) and the novel phosphatase Slingshot (SSH)1L. In human VSMCs, stimulation with PDGF increased G-actin incorporation into the actin cytoskeleton. PDGF transiently activated the cofilin kinase, LIMK, with a peak at 5 minutes. However, cofilin was dephosphorylated between 5 and 45 minutes, with a maximum of 43+/-5% dephosphorylation at 30 minutes, suggesting that PDGF also activates a cofilin phosphatase. We found that VSMCs express SSH1L, which is induced and activated (564+/-73 versus 1021+/-141 picomoles of PO(4); P=0.015) by PDGF. Of importance, small interfering RNA directed against SSH1L blocked cofilin dephosphorylation and decreased migration (528+/-33 versus 318+/-25 cells/field; P<0.01). Taken together, our results suggest that PDGF participates in actin dynamics by dual regulation of cofilin activity via LIMK and SSH1L.

  13. Cell growth and lambda phage development controlled by the same essential Escherichia coli gene, ftsH/hflB.

    PubMed Central

    Herman, C; Ogura, T; Tomoyasu, T; Hiraga, S; Akiyama, Y; Ito, K; Thomas, R; D'Ari, R; Bouloc, P

    1993-01-01

    The lambda phage choice between lysis and lysogeny is influenced by certain host functions in Escherichia coli. We found that the frequency of lambda lysogenization is markedly increased in the ftsH1 temperature-sensitive mutant. The ftsH gene, previously shown to code for an essential inner membrane protein with putative ATPase activity, is identical to hflB, a gene involved in the stability of the phage cII activator protein. The lysogenic decision controlled by FtsH/HflB is independent of that controlled by the protease HflA. Overproduction of FtsH/HflB suppresses the high frequency of lysogenization in an hflA null mutant. The FtsH/HflB protein, which stimulates cII degradation, may be a component of an HflA-independent proteolytic pathway, or it may act as a chaperone, maintaining cII in a conformation subject to proteolysis via such a pathway. Suppressor mutations of ftsH1 temperature-sensitive lethality, located in the fur gene (coding for the ferric uptake regulator), did not restore FtsH/HflB activity with respect to lambda lysogenization. PMID:8248182

  14. Controlled growth of Cu2ZnSnS4 (CZTS) thin films for heterojunction solar-cell applications

    NASA Astrophysics Data System (ADS)

    Inamdar, A. I.; Jeon, Ki-Young; Woo, Hyeon Seok; Jung, Woong; Im, Hyunsik; Kim, Hyungsang

    2012-05-01

    Cu2ZnSnS4 (CZTS) thin films (absorber layers) were successfully synthesized on glass substrates by using a RF magnetron sputtering system. The films were rapidly thermally annealed in a nitrogen atmosphere for 20 minutes to improve the crytallinity. The formation of kesterite structures (JCPDS-26-0575) in the film was confirmed using X-ray diffraction (XRD) measurements. The improved crytallinity of the CZTS with a (112) orientation was observed with increasing annealing temperature. The band gaps of all the as-deposited and annealed films were found to be in the range from 1.97 to 1.55 eV. The films' stoichiometry and morphologies were investigated using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) measurements. The sample annealed at 500 °C showed a uniform granular structure with an elemental composition near stoichiometric CZTS. Next, a buffer layer of ZnS for a heterojuntion solar cell was fabricated using a chemical bath deposition (CBD) technique. The films adhered well, were optically transparent and had band gap energy of 3.6 eV.

  15. Controllable Growth of Perovskite Films by Room-Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells.

    PubMed

    Yang, Bin; Dyck, Ondrej; Poplawsky, Jonathan; Keum, Jong; Das, Sanjib; Puretzky, Alexander; Aytug, Tolga; Joshi, Pooran C; Rouleau, Christopher M; Duscher, Gerd; Geohegan, David B; Xiao, Kai

    2015-12-01

    A two-step solution processing approach has been established to grow void-free perovskite films for low-cost high-performance planar heterojunction photovoltaic devices. A high-temperature thermal annealing treatment was applied to drive the diffusion of CH3NH3I precursor molecules into a compact PbI2 layer to form perovskite films. However, thermal annealing for extended periods led to degraded device performance owing to the defects generated by decomposition of perovskite into PbI2. A controllable layer-by-layer spin-coating method was used to grow "bilayer" CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I layers by a simple air exposure at room temperature for making well-oriented, highly crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ca. 800 nm and a high device efficiency of 15.6%, which is comparable to values reported for thermally annealed perovskite films.

  16. Controllable Growth of Perovskite Films by Room-Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells

    SciTech Connect

    Yang, Bin; Dyck, Ondrej; Poplawsky, Jonathan; Keum, Jong; Das, Sanjib; Puretzky, Alexander; Aytug, Tolga; Joshi, Pooran C.; Rouleau, Christopher M.; Duscher, Gerd; Geohegan, David B.; Xiao, Kai

    2015-12-01

    A two-step-solution-processing approach has been established to grow void-free perovskite films for low-cost and high-performance planar heterojunction photovoltaic devices. We generally applied a high-temperature thermal annealing treatment in order to drive the diffusion of CH3NH3I precursor molecules into the compact PbI2 layer to form perovskite films. But, thermal annealing for extended periods would lead to degraded device performance due to the defects generated by decomposition of perovskite into PbI2. In this work, we explored a controllable layer-by-layer spin-coating method to grow bilayer CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I layers by a simple room-temperature-air-exposure for making well-oriented, highly-crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ~ 800 nm and high device efficiency of 15.6%, which is comparable to the reported values from thermally-annealed perovskite films based counterparts. Finally, the simplicity and high device performance of this processing approach is highly promising for direct integration into industrial-scale device manufacture.

  17. Controllable Growth of Perovskite Films by Room-Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells

    DOE PAGES

    Yang, Bin; Dyck, Ondrej; Poplawsky, Jonathan; ...

    2015-12-01

    A two-step-solution-processing approach has been established to grow void-free perovskite films for low-cost and high-performance planar heterojunction photovoltaic devices. We generally applied a high-temperature thermal annealing treatment in order to drive the diffusion of CH3NH3I precursor molecules into the compact PbI2 layer to form perovskite films. But, thermal annealing for extended periods would lead to degraded device performance due to the defects generated by decomposition of perovskite into PbI2. In this work, we explored a controllable layer-by-layer spin-coating method to grow bilayer CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I layers by a simple room-temperature-air-exposure for makingmore » well-oriented, highly-crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ~ 800 nm and high device efficiency of 15.6%, which is comparable to the reported values from thermally-annealed perovskite films based counterparts. Finally, the simplicity and high device performance of this processing approach is highly promising for direct integration into industrial-scale device manufacture.« less

  18. Cell-Size Control

    PubMed Central

    Amodeo, Amanda A.; Skotheim, Jan M.

    2015-01-01

    Cells of a given type maintain a characteristic cell size to function efficiently in their ecological or organismal context. They achieve this through the regulation of growth rates or by actively sensing size and coupling this signal to cell division. We focus this review on potential size-sensing mechanisms, including geometric, external cue, and titration mechanisms. Mechanisms that titrate proteins against DNA are of particular interest because they are consistent with the robust correlation of DNA content and cell size. We review the literature, which suggests that titration mechanisms may underlie cell-size sensing in Xenopus embryos, budding yeast, and Escherichia coli, whereas alternative mechanisms may function in fission yeast. PMID:26254313

  19. Effects of Fibroblast Growth Factor 9 (FGF9) on Steroidogenesis and Gene Expression and Control of FGF9 mRNA in Bovine Granulosa Cells

    PubMed Central

    Schreiber, Nicole B.

    2012-01-01

    Gene expression of fibroblast growth factor-9 (FGF9) is decreased in granulosa cells (GC) of cystic follicles compared with normal dominant follicles in cattle. The objectives of this study were to investigate the effects of FGF9 on GC steroidogenesis, gene expression, and cell proliferation and to determine the hormonal control of GC FGF9 production. GC were collected from small (1–5 mm) and large (8–22 mm) bovine follicles and treated in vitro with various hormones in serum-free medium for 24 or 48 h. In small- and large-follicle GC, FGF9 inhibited (P < 0.05) IGF-I-, dibutyryl cAMP-, and forskolin-induced progesterone and estradiol production. In contrast, FGF9 increased (P < 0.05) GC numbers induced by IGF-I and 10% fetal calf serum. FGF9 inhibited (P < 0.05) FSHR and CYP11A1 mRNA abundance in small- and large-follicle GC but had no effect (P > 0.10) on CYP19A1 or StAR mRNA. In the presence of a 3β-hydroxysteroid dehydrogenase inhibitor, trilostane, FGF9 also decreased (P < 0.05) pregnenolone production. IGF-I inhibited (P < 0.05) whereas estradiol and FSH had no effect (P > 0.10) on FGF9 mRNA abundance. TNFα and wingless-type mouse mammary tumor virus integration site family member-3A decreased (P < 0.05) whereas T4 and sonic hedgehog increased (P < 0.05) FGF9 mRNA abundance in control and IGF-I-treated GC. Thus, GC FGF9 gene expression is hormonally regulated, and FGF9 may act as an autocrine regulator of ovarian function by slowing follicular differentiation via inhibiting IGF-I action, gonadotropin receptors, the cAMP signaling cascade, and steroid synthesis while stimulating GC proliferation in cattle. PMID:22798350

  20. Antizyme (AZ) regulates intestinal cell growth independently of polyamines

    PubMed Central

    Ray, Ramesh M.; Bhattacharya, Sujoy; Bavaria, Mitul N.; Viar, Mary Jane; Johnson, Leonard R.

    2014-01-01

    Since antizyme (AZ) is known to inhibit cell proliferation and to increase apoptosis, the question arises as to whether these effects occur independently of polyamines. Intestinal epithelial cells (IEC-6) were grown in control medium and medium containing 5mM difluoromethylornithine (DFMO) to inhibit ODC, DFMO + 5μM spermidine (SPD), DFMO+ 5μM spermine (SPM), or DFMO+ 10 μM putrescine (PUT) for 4 days and various parameters of growth were measured along with AZ levels. Cell counts were significantly decreased and mean doubling times were significantly increased by DFMO. Putrescine restored growth in the presence of DFMO. However, both SPD and SPM when added with DFMO caused a much greater inhibition of growth than did DFMO alone, and both of these polyamines caused a dramatic increase in AZ. The addition of SPD or SPM to media containing DFMO + PUT significantly inhibited growth and caused a significant increase in AZ. IEC-6 cells transfected with AZ-siRNA grew more than twice as rapidly as either control cells or those incubated with DFMO, indicating that removal of AZ increases growth in cells in which polyamine synthesis is inhibited as well as in control cells. In a separate experiment the addition of SPD increased AZ levels and inhibited growth of cells incubated with DFMO by 50%. The addition of 10 mM asparagine (ASN) prevented the increase in AZ and restored growth to control levels. These results show that cell growth in the presence or absence of ODC activity and in the presence or absence of polyamines depends only on the levels of AZ. Therefore, the effects of AZ on cell growth are independent of polyamines. PMID:24930035

  1. Giardia duodenalis: enhanced growth in cell culture.

    PubMed

    Bowie, W R; Isaac-Renton, J L; Prasad, N

    1988-01-01

    Growth of Giardia duodenalis in broth and in animals has been studied in considerable detail. In contrast, the kinetics of growth in cell culture have been little evaluated. In this study, in vitro growth of G. duodenalis was evaluated in cell culture, primarily using mouse McCoy cells in vials. The media used were Giardia broth (TYI-G), Trichomonas vaginalis broth (TYI-T), and standard cell culture media (CMGA) alone and in combination (2 parts by volume CMGA to one part of TYI broth). Addition of cell culture enhanced the sensitivity of the systems in detecting low numbers of G. duodenalis. Growth was identified consistently with inocula less than or equal to 10/ml, and often with a calculated 10-1/ml inoculum with CMGA/TYI-T and CMGA/TYI-G with cells, and with TYI-G with and without cells. The 2 preferred systems for sensitivity and growth were CMGA/TYI-G with cells and TYI-G with cells. The pH fell minimally in the growth systems and, if CMGA was in the media, cell monolayers remained intact and viable throughout the experiment. In preliminary experiments, cell cultures did not allow growth of one strain of G. muris. These cell culture systems may be useful for detection of low numbers of non-laboratory adapted trophozoites, and should be useful in evaluating the interaction of G. dudodenalis with cells in culture.

  2. The Molecular Control of Blood Cell Development

    NASA Astrophysics Data System (ADS)

    Sachs, Leo

    1987-12-01

    The establishment of a cell culture system for the clonal development of blood cells has made it possible to identify the proteins that regulate the growth and differentiation of different blood cell lineages and to discover the molecular basis of normal and abnormal cell development in blood forming tissues. A model system with myeloid blood cells has shown that (i) normal blood cells require different proteins to induce cell multiplication (growth inducers) and cell differentiation (differentiation inducers), (ii) there is a hierarchy of growth inducers as cells become more restricted in their developmental program, and (iii) a cascade of interactions between proteins determines the correct balance between immature and mature cells in normal blood cell development. Gene cloning has shown that there is a family of different genes for these proteins. Normal protein regulators of blood cell development can control the abnormal growth of certain types of leukemic cells and suppress malignancy by incuding differentiation to mature nondividing cells. Chromosome abnormalities that give rise to malignancy in these leukemic cells can be bypassed and their effects nullified by inducing differentiation, which stops cells from multiplying. These blood cell regulatory proteins are active in culture and in the body, and they can be used clinically to correct defects in blood cell development.

  3. Jasmonate Controls Leaf Growth by Repressing Cell Proliferation and the Onset of Endoreduplication while Maintaining a Potential Stand-By Mode1[W][OA

    PubMed Central

    Noir, Sandra; Bömer, Moritz; Takahashi, Naoki; Ishida, Takashi; Tsui, Tjir-Li; Balbi, Virginia; Shanahan, Hugh; Sugimoto, Keiko; Devoto, Alessandra

    2013-01-01

    Phytohormones regulate plant growth from cell division to organ development. Jasmonates (JAs) are signaling molecules that have been implicated in stress-induced responses. However, they have also been shown to inhibit plant growth, but the mechanisms are not well understood. The effects of methyl jasmonate (MeJA) on leaf growth regulation were investigated in Arabidopsis (Arabidopsis thaliana) mutants altered in JA synthesis and perception, allene oxide synthase and coi1-16B (for coronatine insensitive1), respectively. We show that MeJA inhibits leaf growth through the JA receptor COI1 by reducing both cell number and size. Further investigations using flow cytometry analyses allowed us to evaluate ploidy levels and to monitor cell cycle progression in leaves and cotyledons of Arabidopsis and/or Nicotiana benthamiana at different stages of development. Additionally, a novel global transcription profiling analysis involving continuous treatment with MeJA was carried out to identify the molecular players whose expression is regulated during leaf development by this hormone and COI1. The results of these studies revealed that MeJA delays the switch from the mitotic cell cycle to the endoreduplication cycle, which accompanies cell expansion, in a COI1-dependent manner and inhibits the mitotic cycle itself, arresting cells in G1 phase prior to the S-phase transition. Significantly, we show that MeJA activates critical regulators of endoreduplication and affects the expression of key determinants of DNA replication. Our discoveries also suggest that MeJA may contribute to the maintenance of a cellular “stand-by mode” by keeping the expression of ribosomal genes at an elevated level. Finally, we propose a novel model for MeJA-regulated COI1-dependent leaf growth inhibition. PMID:23439917

  4. Jasmonate controls leaf growth by repressing cell proliferation and the onset of endoreduplication while maintaining a potential stand-by mode.

    PubMed

    Noir, Sandra; Bömer, Moritz; Takahashi, Naoki; Ishida, Takashi; Tsui, Tjir-Li; Balbi, Virginia; Shanahan, Hugh; Sugimoto, Keiko; Devoto, Alessandra

    2013-04-01

    Phytohormones regulate plant growth from cell division to organ development. Jasmonates (JAs) are signaling molecules that have been implicated in stress-induced responses. However, they have also been shown to inhibit plant growth, but the mechanisms are not well understood. The effects of methyl jasmonate (MeJA) on leaf growth regulation were investigated in Arabidopsis (Arabidopsis thaliana) mutants altered in JA synthesis and perception, allene oxide synthase and coi1-16B (for coronatine insensitive1), respectively. We show that MeJA inhibits leaf growth through the JA receptor COI1 by reducing both cell number and size. Further investigations using flow cytometry analyses allowed us to evaluate ploidy levels and to monitor cell cycle progression in leaves and cotyledons of Arabidopsis and/or Nicotiana benthamiana at different stages of development. Additionally, a novel global transcription profiling analysis involving continuous treatment with MeJA was carried out to identify the molecular players whose expression is regulated during leaf development by this hormone and COI1. The results of these studies revealed that MeJA delays the switch from the mitotic cell cycle to the endoreduplication cycle, which accompanies cell expansion, in a COI1-dependent manner and inhibits the mitotic cycle itself, arresting cells in G1 phase prior to the S-phase transition. Significantly, we show that MeJA activates critical regulators of endoreduplication and affects the expression of key determinants of DNA replication. Our discoveries also suggest that MeJA may contribute to the maintenance of a cellular "stand-by mode" by keeping the expression of ribosomal genes at an elevated level. Finally, we propose a novel model for MeJA-regulated COI1-dependent leaf growth inhibition.

  5. S-Fms signalobody enhances myeloid cell growth and migration.

    PubMed

    Kawahara, Masahiro; Hitomi, Azusa; Nagamune, Teruyuki

    2014-07-01

    Since receptor tyrosine kinases (RTKs) control various cell fates in many types of cells, mimicry of RTK functions is promising for artificial control of cell fates. We have previously developed single-chain Fv (scFv)/receptor chimeras named signalobodies that can mimic receptor signaling in response to a specific antigen. While the RTK-based signalobodies enabled us to control cell growth and migration, further extension of applicability in another cell type would underlie the impact of the RTK-based signalobodies. In this study, we applied the scFv-c-Fms (S-Fms) signalobody in a murine myeloid progenitor cell line, FDC-P1. S-Fms transduced a fluorescein-conjugated BSA (BSA-FL)-dependent growth signal and activated downstream signaling molecules including MEK, ERK, Akt, and STAT3, which are major constituents of Ras/MAPK, PI3K/Akt, and JAK/STAT signaling pathways. In addition, S-Fms transduced a migration signal as demonstrated by the transwell-based migration assay. Direct real-time observation of the cells further confirmed that FDC/S-Fms cells underwent directional cell migration toward a positive gradient of BSA-FL. These results demonstrated the utility of the S-Fms signalobody for controlling growth and migration of myeloid cells. Further extension of our approach includes economical large-scale production of practically relevant blood cells as well as artificial control of cell migration for tissue regeneration and immune response.

  6. Conditioned medium from neural stem cells inhibits glioma cell growth.

    PubMed

    Li, Z; Zhong, Q; Liu, H; Liu, P; Wu, J; Ma, D; Chen, X; Yang, X

    2016-10-31

    Malignant glioma is one of the most common brain tumors in the central nervous system. Although the significant progress has been made in recent years, the mortality is still high and 5-year survival rate is still very low. One of the leading causes to the high mortality for glioma patients is metastasis and invasion. An efficient method to control the tumor metastasis is a promising way to treat the glioma. Previous reports indicated that neural stem cells (NSCs) were served as a delivery vector to the anti-glioma therapy. Here, we used the conditioned medium from rat NSCs (NSC-CM) to culture the human glioblastoma cell lines. We found that NSC-CM could inhibit the glioma cell growth, invasion and migration in vitro and attenuate the tumor growth in vivo. Furthermore, this anti-glioma effect was mediated by the inactivation of mitogen activated protein kinase (MAPK) pathway. Above all, this study provided the direct evidence to put forward a simple and efficient method in the inhibition of glioma cells/tumor growth, potentially advancing the anti-glioma therapy.

  7. Stochastic Gompertz model of tumour cell growth.

    PubMed

    Lo, C F

    2007-09-21

    In this communication, based upon the deterministic Gompertz law of cell growth, a stochastic model in tumour growth is proposed. This model takes account of both cell fission and mortality too. The corresponding density function of the size of the tumour cells obeys a functional Fokker--Planck equation which can be solved analytically. It is found that the density function exhibits an interesting "multi-peak" structure generated by cell fission as time evolves. Within this framework the action of therapy is also examined by simply incorporating a therapy term into the deterministic cell growth term.

  8. Glycoside Hydrolase MoGls2 Controls Asexual/Sexual Development, Cell Wall Integrity and Infectious Growth in the Rice Blast Fungus.

    PubMed

    Li, Mengying; Liu, Xinyu; Liu, Zhixi; Sun, Yi; Liu, Muxing; Wang, Xiaoli; Zhang, Haifeng; Zheng, Xiaobo; Zhang, Zhengguang

    2016-01-01

    N-linked glycosylation is a way of glycosylation for newly synthesized protein, which plays a key role in the maturation and transport of proteins. Glycoside hydrolases (GHs) are essential in this process, and are involved in processing of N-linked glycoproteins or degradation of carbohydrate structures. Here, we identified and characterized MoGls2 in Magnaporthe oryzae, which is a yeast glucosidase II homolog Gls2 and is required for trimming the final glucose in N-linked glycans and normal cell wall synthesis. Target deletion of MoGLS2 in M. oryzae resulted in a reduced mycelial growth, an increased conidial production, delayed conidial germination and loss the ability of sexual reproduction. Pathogenicity assays revealed that the ΔMogls2 mutant showed significantly decreased in virulence and infectious growth. Further studies showed that the mutant was less sensitive to salt and osmotic stress, and increased sensitivity to cell wall stresses. Additionally, the ΔMogls2 mutant showed a defect in cell wall integrity. Our results indicate that MoGls2 is a key protein for the growth and development of M. oryzae, involving in the regulation of asexual/sexual development, stress response, cell wall integrity and infectious growth.

  9. Glycoside Hydrolase MoGls2 Controls Asexual/Sexual Development, Cell Wall Integrity and Infectious Growth in the Rice Blast Fungus

    PubMed Central

    Li, Mengying; Liu, Xinyu; Liu, Zhixi; Sun, Yi; Liu, Muxing; Wang, Xiaoli; Zhang, Haifeng; Zheng, Xiaobo; Zhang, Zhengguang

    2016-01-01

    N-linked glycosylation is a way of glycosylation for newly synthesized protein, which plays a key role in the maturation and transport of proteins. Glycoside hydrolases (GHs) are essential in this process, and are involved in processing of N-linked glycoproteins or degradation of carbohydrate structures. Here, we identified and characterized MoGls2 in Magnaporthe oryzae, which is a yeast glucosidase II homolog Gls2 and is required for trimming the final glucose in N-linked glycans and normal cell wall synthesis. Target deletion of MoGLS2 in M. oryzae resulted in a reduced mycelial growth, an increased conidial production, delayed conidial germination and loss the ability of sexual reproduction. Pathogenicity assays revealed that the ΔMogls2 mutant showed significantly decreased in virulence and infectious growth. Further studies showed that the mutant was less sensitive to salt and osmotic stress, and increased sensitivity to cell wall stresses. Additionally, the ΔMogls2 mutant showed a defect in cell wall integrity. Our results indicate that MoGls2 is a key protein for the growth and development of M. oryzae, involving in the regulation of asexual/sexual development, stress response, cell wall integrity and infectious growth. PMID:27607237

  10. Controlled growth of semiconductor crystals

    DOEpatents

    Bourret-Courchesne, Edith D.

    1992-01-01

    A method for growth of III-V, II-VI and related semiconductor single crystals that suppresses random nucleation and sticking of the semiconductor melt at the crucible walls. Small pieces of an oxide of boron B.sub.x O.sub.y are dispersed throughout the comminuted solid semiconductor charge in the crucible, with the oxide of boron preferably having water content of at least 600 ppm. The crucible temperature is first raised to a temperature greater than the melt temperature T.sub.m1 of the oxide of boron (T.sub.m1 =723.degree. K. for boron oxide B.sub.2 O.sub.3), and the oxide of boron is allowed to melt and form a reasonably uniform liquid layer between the crucible walls and bottom surfaces and the still-solid semiconductor charge. The temperature is then raised to approximately the melt temperature T.sub.m2 of the semiconductor charge material, and crystal growth proceeds by a liquid encapsulated, vertical gradient freeze process. About half of the crystals grown have a dislocation density of less than 1000/cm.sup.2. If the oxide of boron has water content less than 600 ppm, the crucible material should include boron nitride, a layer of the inner surface of the crucible should be oxidized before the oxide of boron in the crucible charge is melted, and the sum of thicknesses of the solid boron oxide layer and liquid boron oxide layer should be at least 50 .mu.m.

  11. Controlled growth of semiconductor crystals

    DOEpatents

    Bourret-Courchesne, E.D.

    1992-07-21

    A method is disclosed for growth of III-V, II-VI and related semiconductor single crystals that suppresses random nucleation and sticking of the semiconductor melt at the crucible walls. Small pieces of an oxide of boron B[sub x]O[sub y] are dispersed throughout the comminuted solid semiconductor charge in the crucible, with the oxide of boron preferably having water content of at least 600 ppm. The crucible temperature is first raised to a temperature greater than the melt temperature T[sub m1] of the oxide of boron (T[sub m1]=723 K for boron oxide B[sub 2]O[sub 3]), and the oxide of boron is allowed to melt and form a reasonably uniform liquid layer between the crucible walls and bottom surfaces and the still-solid semiconductor charge. The temperature is then raised to approximately the melt temperature T[sub m2] of the semiconductor charge material, and crystal growth proceeds by a liquid encapsulated, vertical gradient freeze process. About half of the crystals grown have a dislocation density of less than 1000/cm[sup 2]. If the oxide of boron has water content less than 600 ppm, the crucible material should include boron nitride, a layer of the inner surface of the crucible should be oxidized before the oxide of boron in the crucible charge is melted, and the sum of thicknesses of the solid boron oxide layer and liquid boron oxide layer should be at least 50 [mu]m. 7 figs.

  12. Identification of specific adenovirus E1A N-terminal residues critical to the binding of cellular proteins and to the control of cell growth.

    PubMed Central

    Wang, H G; Rikitake, Y; Carter, M C; Yaciuk, P; Abraham, S E; Zerler, B; Moran, E

    1993-01-01

    Adenovirus early region 1A (E1A) oncogene-encoded sequences essential for transformation- and cell growth-regulating activities are localized at the N terminus and in regions of highly conserved amino acid sequence designated conserved regions 1 and 2. These regions interact to form the binding sites for two classes of cellular proteins: those, such as the retinoblastoma gene product, whose association with the E1A products is specifically dependent on region 2, and another class which so far is known to include only a large cellular DNA-binding protein, p300, whose association with the E1A products is specifically dependent on the N-terminal region. Association between the E1A products and either class of cellular proteins can be disrupted by mutations in conserved region 1. While region 2 has been studied intensively, very little is known so far concerning the nature of the essential residues in the N-terminal region, or about the manner in which conserved region 1 participates in the binding of two distinct sets of cellular proteins. A combination of site-directed point mutagenesis and monoclonal antibody competition experiments reported here suggests that p300 binding is dependent on specific, conserved residues in the N terminus, including positively charged residues at positions 2 and 3 of the E1A proteins, and that p300 and pRB bind to distinct, nonoverlapping subregions within conserved region 1. The availability of precise point mutations disrupting p300 binding supports previous data linking p300 with cell cycle control and enhancer function. Images PMID:8416379

  13. Control of MicroRNA-21 expression in colorectal cancer cells by oncogenic epidermal growth factor/Ras signaling and Ets transcription factors.

    PubMed

    Kern, Hanna B; Niemeyer, Brian F; Parrish, Janet K; Kerr, Carol A; Yaghi, Nasser K; Prescott, Jason D; Gutierrez-Hartmann, Arthur; Jedlicka, Paul

    2012-08-01

    MicroRNAs (miRs) are important regulators of gene expression in normal physiology and disease, and are widely misexpressed in cancer. A number of studies have identified miR-21 as an important promoter of oncogenesis. However, as is true of most miRs, the mechanisms behind the aberrant expression of miR-21 in cancer are poorly understood. Herein, we examine the regulation of miR-21 expression in colorectal cancer (CRC) cells by the oncogenic epidermal growth factor (EGF)/Ras pathway and by Ets transcription factors, modulators of epithelial oncogenesis that are frequently misexpressed in CRC. We show that EGF/Ras efficiently induces the miR-21 primary transcript, but this does not rapidly and simply translate into higher mature miR-21 levels. Rather, induction of mature miR-21 by constitutive activation of this pathway is slow, is associated with only minimal activation of mitogen-activated protein kinase, and may involve stimulation of post-transcriptional processing by mechanisms other than Dicer stabilization. We further identify Ets transcription factors as modifiers of miR-21 expression in CRC. The effects of Ets factors on miR-21 expression are cell context-dependent, and appear to involve both direct and indirect mechanisms. The Ets factor Pea3 emerges from our studies as a consistent repressor of miR-21 transcription. Overall, our studies identify a complex relationship between oncogenic pathways and steady-state miR-21 levels in CRC, and highlight the need for greater understanding of the control of miR expression in cancer and other disease states.

  14. Proliferative control in Drosophila stem cells.

    PubMed

    Kohlmaier, Alexander; Edgar, Bruce A

    2008-12-01

    The relationship between cell growth (cell mass increase over time) and cell division is poorly understood in animal stem cells. Recent studies in several Drosophila stem cell types have provided the tools to interrogate this relationship. In several cases (brat, mei-P26, pros, bam, lethal giant larvae, polo), mutations have been defined that trigger tumorous overproliferation of progenitor cells and reveal how unrestricted self-renewing capacity is controlled. Moreover, microRNAs have been discovered as essential regulators of stem cell division rate and identity, suggesting that stem cell self-renewal depends on protein translational control. Biosynthetic capacity has also been found to be limiting for stem cell division rates. Finally, asymmetric cell division can impose dominant differentiation signals in a stem cell's daughter, and this can inhibit the stem cell-specific proliferation signature and lock in cell cycle exit.

  15. Interface control and snow crystal growth

    NASA Astrophysics Data System (ADS)

    Li, Jessica; Schaposnik, Laura P.

    2016-02-01

    The growth of snow crystals is dependent on the temperature and saturation of the environment. In the case of dendrites, Reiter's local two-dimensional model provides a realistic approach to the study of dendrite growth. In this paper we obtain a new geometric rule that incorporates interface control, a basic mechanism of crystallization that is not taken into account in the original Reiter model. By defining two new variables, growth latency and growth direction, our improved model gives a realistic model not only for dendrite but also for plate forms.

  16. Integrative nuclear FGFR1 signaling (INFS) as a part of a universal "feed-forward-and-gate" signaling module that controls cell growth and differentiation.

    PubMed

    Stachowiak, Michal K; Fang, Xiaohong; Myers, Jason M; Dunham, Star M; Berezney, Ronald; Maher, Pamela A; Stachowiak, Ewa K

    2003-11-01

    A novel signaling mechanism is described through which extracellular signals and intracellular signaling pathways regulate proliferation, growth, differentiation, and other functions of cells in the nervous system. Upon cell stimulation, fibroblast growth factor receptor-1 (FGFR1), a typically plasma membrane-associated protein, is released from ER membranes into the cytosol and translocates to the cell nucleus by an importin-beta-mediated transport pathway along with its ligand, FGF-2. The nuclear accumulation of FGFR1 is activated by changes in cell contacts and by stimulation of cells with growth factors, neurotransmitters and hormones as well as by a variety of different second messengers and thus was named integrative nuclear FGFR1 signaling (INFS). In the nucleus, FGFR1 localizes specifically within nuclear matrix-attached speckle-domains, which are known to be sites for RNA Pol II-mediated transcription and co-transcriptional pre-mRNA processing. In these domains, nuclear FGFR1 colocalizes with RNA transcription sites, splicing factors, modified histones, phosphorylated RNA Pol II, and signaling kinases. Within the nucleus, FGFR1 serves as a general transcriptional regulator, as indicated by its association with the majority of active nuclear centers of RNA synthesis and processing, by the ability of nuclear FGFR1 to activate structurally distinct genes located on different chromosomes and by its stimulation of multi-gene programs for cell growth and differentiation. We propose that FGFR1 is part of a universal "feed-forward-and-gate" signaling module in which classical signaling cascades initiated by specific membrane receptors transmit signals to sequence specific transcription factors (ssTFs), while INFS elicited by the same stimuli feeds the signal forward to the common coactivator, CREB-binding protein (CBP). Activation of CBP by INFS, along with the activation of ssTFs by classical signaling cascades brings about coordinated responses from structurally

  17. Growing Out of Stress: The Role of Cell- and Organ-Scale Growth Control in Plant Water-Stress Responses[OPEN

    PubMed Central

    Robbins, Neil E.

    2016-01-01

    Water is the most limiting resource on land for plant growth, and its uptake by plants is affected by many abiotic stresses, such as salinity, cold, heat, and drought. While much research has focused on exploring the molecular mechanisms underlying the cellular signaling events governing water-stress responses, it is also important to consider the role organismal structure plays as a context for such responses. The regulation of growth in plants occurs at two spatial scales: the cell and the organ. In this review, we focus on how the regulation of growth at these different spatial scales enables plants to acclimate to water-deficit stress. The cell wall is discussed with respect to how the physical properties of this structure affect water loss and how regulatory mechanisms that affect wall extensibility maintain growth under water deficit. At a higher spatial scale, the architecture of the root system represents a highly dynamic physical network that facilitates access of the plant to a heterogeneous distribution of water in soil. We discuss the role differential growth plays in shaping the structure of this system and the physiological implications of such changes. PMID:27503468

  18. Postembryonic control of root meristem growth and development.

    PubMed

    Sozzani, Rosangela; Iyer-Pascuzzi, Anjali

    2014-02-01

    Organ development in multicellular organisms is dependent on the proper balance between cell proliferation and differentiation. In the Arabidopsis root apical meristem, meristem growth is the result of cell divisions in the proximal meristem and cell differentiation in the elongation and differentiation zones. Hormones, transcription factors and small peptides underpin the molecular mechanisms governing these processes. Computer modeling has aided our understanding of the dynamic interactions involved in stem cell maintenance and meristem activity. Here we review recent advances in our understanding of postembryonic root stem cell maintenance and control of meristem size. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. UV absorption control of thin film growth

    DOEpatents

    Biefeld, Robert M.; Hebner, Gregory A.; Killeen, Kevin P.; Zuhoski, Steven P.

    1991-01-01

    A system for monitoring and controlling the rate of growth of thin films in an atmosphere of reactant gases measures the UV absorbance of the atmosphere and calculates the partial pressure of the gases. The flow of reactant gases is controlled in response to the partial pressure.

  20. Quantifying the entropic cost of cellular growth control

    NASA Astrophysics Data System (ADS)

    De Martino, Daniele; Capuani, Fabrizio; De Martino, Andrea

    2017-07-01

    Viewing the ways a living cell can organize its metabolism as the phase space of a physical system, regulation can be seen as the ability to reduce the entropy of that space by selecting specific cellular configurations that are, in some sense, optimal. Here we quantify the amount of regulation required to control a cell's growth rate by a maximum-entropy approach to the space of underlying metabolic phenotypes, where a configuration corresponds to a metabolic flux pattern as described by genome-scale models. We link the mean growth rate achieved by a population of cells to the minimal amount of metabolic regulation needed to achieve it through a phase diagram that highlights how growth suppression can be as costly (in regulatory terms) as growth enhancement. Moreover, we provide an interpretation of the inverse temperature β controlling maximum-entropy distributions based on the underlying growth dynamics. Specifically, we show that the asymptotic value of β for a cell population can be expected to depend on (i) the carrying capacity of the environment, (ii) the initial size of the colony, and (iii) the probability distribution from which the inoculum was sampled. Results obtained for E. coli and human cells are found to be remarkably consistent with empirical evidence.

  1. The suppression of prostate LNCaP cancer cells growth by Selenium nanoparticles through Akt/Mdm2/AR controlled apoptosis.

    PubMed

    Kong, Ling; Yuan, Qing; Zhu, Huarui; Li, Ying; Guo, Quanyi; Wang, Qin; Bi, Xiaolin; Gao, Xueyun

    2011-09-01

    The trace element Selenium is suggested having cancer prevention activity and used as food supplement. Previous results had shown Selenium nanoparticles are safer compared with other Selenium compounds like selenomethionine, sodium selenite and monomethylated Selenium, however, its anticancer activity and intrinsic mechanisms are still elusive. Here, we prepared Selenium nanoparticles and investigated its inherent anticancer mechanisms. We found Selenium nanoparticles inhibit growth of prostate LNCaP cancer cells partially through caspases mediated apoptosis. Selenium nanoparticles suppress transcriptional activity of androgen receptor via down-regulating its mRNA and protein expression. Moreover, Selenium nanoparticles activate Akt kinase by increasing its phosphorylation, promote Akt-dependent androgen receptor phosphorylation and Mdm2 regulated degradation through proteasome pathway. We suggest Selenium nanoparticles suppress prostate cancer cells growth by disrupting androgen receptor, implicating a potential application in cancer treatment.

  2. ELF3 controls thermoresponsive growth in Arabidopsis.

    PubMed

    Box, Mathew S; Huang, B Emma; Domijan, Mirela; Jaeger, Katja E; Khattak, Asif Khan; Yoo, Seong Jeon; Sedivy, Emma L; Jones, D Marc; Hearn, Timothy J; Webb, Alex A R; Grant, Alastair; Locke, James C W; Wigge, Philip A

    2015-01-19

    Plant development is highly responsive to ambient temperature, and this trait has been linked to the ability of plants to adapt to climate change. The mechanisms by which natural populations modulate their thermoresponsiveness are not known. To address this, we surveyed Arabidopsis accessions for variation in thermal responsiveness of elongation growth and mapped the corresponding loci. We find that the transcriptional regulator EARLY FLOWERING3 (ELF3) controls elongation growth in response to temperature. Through a combination of modeling and experiments, we show that high temperature relieves the gating of growth at night, highlighting the importance of temperature-dependent repressors of growth. ELF3 gating of transcriptional targets responds rapidly and reversibly to changes in temperature. We show that the binding of ELF3 to target promoters is temperature dependent, suggesting a mechanism where temperature directly controls ELF3 activity.

  3. Do glial cells control pain?

    PubMed Central

    Suter, Marc R; Wen, Yeong-Ray; Decosterd, Isabelle; Ji, Ru-Rong

    2008-01-01

    Management of chronic pain is a real challenge, and current treatments focusing on blocking neurotransmission in the pain pathway have only resulted in limited success. Activation of glia cells has been widely implicated in neuroinflammation in the central nervous system, leading to neruodegeneration in many disease conditions such as Alzheimer’s and multiple sclerosis. The inflammatory mediators released by activated glial cells, such as tumor necrosis factor-α and interleukin-1β can not only cause neurodegeneration in these disease conditions, but also cause abnormal pain by acting on spinal cord dorsal horn neurons in injury conditions. Pain can also be potentiated by growth factors such as BDNF and bFGF that are produced by glia to protect neurons. Thus, glia cells can powerfully control pain when they are activated to produce various pain mediators. We will review accumulating evidence supporting an important role of microglia cells in the spinal cord for pain control under injury conditions (e.g. nerve injury). We will also discuss possible signaling mechanisms in particular MAP kinase pathways that are critical for glia control of pain. Investigating signaling mechanisms in microglia may lead to more effective management of devastating chronic pain. PMID:18504511

  4. Platelet-Rich Plasma Increases Growth and Motility of Adipose Tissue-Derived Mesenchymal Stem Cells and Controls Adipocyte Secretory Function.

    PubMed

    D'Esposito, Vittoria; Passaretti, Federica; Perruolo, Giuseppe; Ambrosio, Maria Rosaria; Valentino, Rossella; Oriente, Francesco; Raciti, Gregory A; Nigro, Cecilia; Miele, Claudia; Sammartino, Gilberto; Beguinot, Francesco; Formisano, Pietro

    2015-10-01

    Adipose tissue-derived mesenchymal stem cells (Ad-MSC) and platelet derivatives have been used alone or in combination to achieve regeneration of injured tissues. We have tested the effect of platelet-rich plasma (PRP) on Ad-MSC and adipocyte function. PRP increased Ad-MSC viability, proliferation rate and G1-S cell cycle progression, by at least 7-, 2-, and 2.2-fold, respectively, and reduced caspase 3 cleavage. Higher PRP concentrations or PRPs derived from individuals with higher platelet counts were more effective in increasing Ad-MSC growth. PRP also accelerated cell migration by at least 1.5-fold. However, PRP did not significantly affect mature adipocyte viability, differentiation and expression levels of PPAR-γ and AP-2 mRNAs, while it increased leptin production by 3.5-fold. Interestingly, PRP treatment of mature adipocytes also enhanced the release of Interleukin (IL)-6, IL-8, IL-10, Interferon-γ, and Vascular Endothelial Growth Factor. Thus, data are consistent with a stimulatory effect of platelet derivatives on Ad-MSC growth and motility. Moreover, PRP did not reduce mature adipocyte survival and increased the release of pro-angiogenic factors, which may facilitate tissue regeneration processes.

  5. Photoperiodic growth control in perennial trees.

    PubMed

    Azeez, Abdul; Sane, Aniruddha P

    2015-01-01

    Plants have to cope with changing seasons and adverse environmental conditions. Being sessile, plants have developed elaborate mechanisms for their survival that allow them to sense and adapt to the environment and reproduce successfully. A major adaptive trait for the survival of trees of temperate and boreal forests is the induction of growth cessation in anticipation of winters. In the last few years enormous progress has been made to elucidate the molecular mechanisms underlying SDs induced growth cessation in model perennial tree hybrid aspen (Populus tremula × P. tremuloides). In this review we discuss the molecular mechanism underlying photoperiodic control of growth cessation and adaptive responses.

  6. Photoperiodic growth control in perennial trees

    PubMed Central

    Azeez, Abdul; Sane, Aniruddha P

    2015-01-01

    Plants have to cope with changing seasons and adverse environmental conditions. Being sessile, plants have developed elaborate mechanisms for their survival that allow them to sense and adapt to the environment and reproduce successfully. A major adaptive trait for the survival of trees of temperate and boreal forests is the induction of growth cessation in anticipation of winters. In the last few years enormous progress has been made to elucidate the molecular mechanisms underlying SDs induced growth cessation in model perennial tree hybrid aspen (Populus tremula × P. tremuloides). In this review we discuss the molecular mechanism underlying photoperiodic control of growth cessation and adaptive responses. PMID:26340077

  7. Enhanced Growth of amniotic fluid cells in presence of fibroblast growth factor.

    PubMed

    Porreco, R P; Bradshaw, C; Sarkar, S; Jones, O W

    1980-01-01

    A shorter period of time between amniocentesis and cytogenetic diagnosis is of considerable clinical usefulness. Fibroblast growth factor (FGF), a potent mitogen for cells of mesodermal origin, was used to enhance the growth rate of primary cultures of amniotic fluid-derived cells. At the initial harvest and at 5 scored metaphases, culture dishes incubated with FGF showed a 9-day advantage as a group when compared with their untreated, paired controls. In addition, less variability was encountered in the growth time of the FGF-treated dishes; 97% of these treated dishes were harvested initially between 10 and 20 days, while only 48% of the control dishes were harvested initially during this time period. Success was also noted in the recovery of failing cultures. The addition of FGF to the standard enriched medium used in amniotic fluid cell cultures has shortened the processing time and provided a more uniform growth rate in the majority of cultures studied.

  8. Paradigm shift in plant growth control.

    PubMed

    Körner, Christian

    2015-06-01

    For plants to grow they need resources and appropriate conditions that these resources are converted into biomass. While acknowledging the importance of co-drivers, the classical view is still that carbon, that is, photosynthetic CO2 uptake, ranks above any other drivers of plant growth. Hence, theory and modelling of growth traditionally is carbon centric. Here, I suggest that this view is not reflecting reality, but emerged from the availability of methods and process understanding at leaf level. In most cases, poorly understood processes of tissue formation and cell growth are governing carbon demand, and thus, CO2 uptake. Carbon can only be converted into biomass to the extent chemical elements other than carbon, temperature or cell turgor permit. Copyright © 2015. Published by Elsevier Ltd.

  9. Oxide Control for Silicon Crystal Growth

    NASA Technical Reports Server (NTRS)

    Wehrli, H. A. I.

    1982-01-01

    Web dendrite growth process pulls sheet of newly crystallized silicon from molten silicon. Jets of argon pull outside gas into melt cavity, preventing silicon oxide from passing through heat-shield hold and depositing on it. Generated by aspirators, reversed flow is used in web dendrite process, which produces sheets of single-crystal silicon for low-cost solar cells.

  10. Overexpression of Numb suppresses growth, migration, and invasion of human clear cell renal cell carcinoma cells.

    PubMed

    Sima, Jin; Zhang, Bao; Yu, Yuanzi; Sima, Xinyuan; Mao, Yanxin

    2015-04-01

    The objective of the study was to investigate the impact of Numb on cell growth, cell migration, and invasion in human clear cell renal cell carcinoma (ccRCC). Endogenous expression of Numb was evaluated in the ccRCC cell lines (786-O, Caki-1, and Caki-2) and control reference human renal proximal tubular epithelial cells. Numb expression was decreased in the ccRCC cells compared with the control cells (P < 0.01). Then, 786-O and Caki-1 cells described as suitable transfection hosts were used in transfection to carry out biological function studies. The three experimental groups were as follows: Numb-ORF (transfected with Numb-ORF plasmid), blank-vector (transfected with pCMV6-entry), and cell-alone group (no DNA). Numb expression in the Numb-ORF groups was significantly higher than that in the controls (P < 0.01). Cell growth was remarkably reduced (P < 0.01), and the number of migrating or invading cells was reduced (P < 0.01) in the Numb-ORF groups compared with controls. Furthermore, the ratio of G0/G1 phase in the Numb-ORF group of 786-O cells was increased, and the S phase fraction and proliferation index was decreased (P < 0.01). Cyclin D1 and MMP-9 expression was reduced in the Numb-ORF groups compared with controls. Here, we have provided data for attenuated Numb expression in the ccRCC cells. Overexpression of Numb could induce G0/G1 phase arrest and inhibit cell proliferation, migration, and invasion. The suppressive effects might be due to downregulation of cyclin D1 or MMP-9 expression. Taken together, our data suggest that Numb may possibly function as a tumor suppressor involved in the carcinogenesis of ccRCC.

  11. NADPH Oxidases NOX-1 and NOX-2 Require the Regulatory Subunit NOR-1 To Control Cell Differentiation and Growth in Neurospora crassa▿ †

    PubMed Central

    Cano-Domínguez, Nallely; Álvarez-Delfín, Karen; Hansberg, Wilhelm; Aguirre, Jesús

    2008-01-01

    We have proposed that reactive oxygen species (ROS) play essential roles in cell differentiation. Enzymes belonging to the NADPH oxidase (NOX) family produce superoxide in a regulated manner. We have identified three distinct NOX subfamilies in the fungal kingdom and have shown that NoxA is required for sexual cell differentiation in Aspergillus nidulans. Here we show that Neurospora crassa NOX-1 elimination results in complete female sterility, decreased asexual development, and reduction of hyphal growth. The lack of NOX-2 did not affect any of these processes but led instead to the production of sexual spores that failed to germinate, even in the presence of exogenous oxidants. The elimination of NOR-1, an ortholog of the mammalian Nox2 regulatory subunit gp67phox, also caused female sterility, the production of unviable sexual spores, and a decrease in asexual development and hyphal growth. These results indicate that NOR-1 is required for NOX-1 and NOX-2 functions at different developmental stages and establish a link between NOX-generated ROS and the regulation of growth. Indeed, NOX-1 was required for the increased asexual sporulation previously observed in mutants without catalase CAT-3. We also analyzed the function of the penta-EF calcium-binding domain protein PEF-1 in N. crassa. Deletion of pef-1 resulted in increased conidiation but, in contrast to what occurs in Dictyostelium discoideum, the mutation of this peflin did not suppress the phenotypes caused by the lack of NOX-1. Our results support the role of ROS as critical cell differentiation signals and highlight a novel role for ROS in regulation of fungal growth. PMID:18567788

  12. Differential Control of Growth, Apoptotic Activity, and Gene Expression in Human Breast Cancer Cells by Extracts Derived from Medicinal Herbs Zingiber officinale

    PubMed Central

    Elkady, Ayman I.; Abuzinadah, Osama A.; Baeshen, Nabih A.; Rahmy, Tarek R.

    2012-01-01

    The present study aimed to examine the antiproliferative potentiality of an extract derived from the medicinal plant ginger (Zingiber officinale) on growth of breast cancer cells. Ginger treatment suppressed the proliferation and colony formation in breast cancer cell lines, MCF-7 and MDA-MB-231. Meanwhile, it did not significantly affect viability of nontumorigenic normal mammary epithelial cell line (MCF-10A). Treatment of MCF-7 and MDA-MB-231 with ginger resulted in sequences of events marked by apoptosis, accompanied by loss of cell viability, chromatin condensation, DNA fragmentation, activation of caspase 3, and cleavage of poly(ADP-ribose) polymerase. At the molecular level, the apoptotic cell death mediated by ginger could be attributed in part to upregulation of Bax and downregulation of Bcl-2 proteins. Ginger treatment downregulated expression of prosurvival genes, such as NF-κB, Bcl-X, Mcl-1, and Survivin, and cell cycle-regulating proteins, including cyclin D1 and cyclin-dependent kinase-4 (CDK-4). On the other hand, it increased expression of CDK inhibitor, p21. It also inhibited the expression of the two prominent molecular targets of cancer, c-Myc and the human telomerase reverse transcriptase (hTERT). These findings suggested that the ginger may be a promising candidate for the treatment of breast carcinomas. PMID:22969274

  13. A requirement for the Vgamma1+ subset of peripheral gammadelta T cells in the control of the systemic growth of Toxoplasma gondii and infection-induced pathology.

    PubMed

    Egan, Charlotte E; Dalton, Jane E; Andrew, Elizabeth M; Smith, Judith E; Gubbels, Marc-Jan; Striepen, Boris; Carding, Simon R

    2005-12-15

    gammadelta T cells are a diverse population of T cells that are widely distributed and are a common feature of pathogen-induced immune responses. It is not clear, however, whether different populations of gammadelta T cells have specific functions, and what factors determine the functional properties of individual populations. A murine model of peroral Toxoplasma gondii infection was used to determine the contribution Vgamma1+ intestinal intraepithelial lymphocytes (IELs) vs systemic Vgamma1+ T cells make to the acute and chronic stages of the host immune response, and whether the macrophage cytocidal activity of Vgamma1+ T cells described in bacterial infections is seen in other, unrelated infectious disease models. In response to oral infection with virulent type 1 or avirulent type II strains of T. gondii, TCR-delta-/- mice rapidly developed severe ileitis. In contrast, in mice deficient in Vgamma1+ T cells and IELs and wild-type mice, inflammation was delayed in onset and less severe. The protective effect of (Vgamma1-) IELs to Toxoplasma infection was unrelated to their cytolytic and cytokine (Th1)-producing capabilities. Systemic Vgamma1+ T cells were shown to play an essential role in limiting parasite growth and inflammation in peripheral tissues and, in particular, in the CNS, that was associated with their ability to efficiently kill parasite-elicited and infected macrophages. These findings suggest that macrophage cytocidal activity of Vgamma1+ T cells may be a universal feature of pathogen-induced immune responses and that microenvironmental factors influence the involvement and function of gammadelta T cells in the host response to infection.

  14. Cancer cells. 3: Growth factors and transformation

    SciTech Connect

    Feramisco, J.; Ozanne, B.; Stiles, C.

    1985-01-01

    This book contains over 50 papers. Some of the titles are: Structure of Human Epidermal Growth Factor and Expression of Normal and Variant mRNAs in Epdermoid Carcinoma Cells; Tyrosine Kinase Activity Associated with the v-erb-B Gene Product; Cloning and Characterization of Human Epidermal Growth Factor-Receptor Gene Sequences in A431 Carcinoma Cells; Anti-oncogenes and the Suppression of Tumor Formation; and Normal Human sis/PDGF-2 Gene Expression Induces Cellular Transformation.

  15. Cloned Hemoglobin Genes Enhance Growth Of Cells

    NASA Technical Reports Server (NTRS)

    Khosla, Chaitan; Bailey, James E.

    1991-01-01

    Experiments show that portable deoxyribonucleic acid (DNA) sequences incorporated into host cells make them produce hemoglobins - oxygen-binding proteins essential to function of red blood cells. Method useful in several biotechnological applications. One, enhancement of growth of cells at higher densities. Another, production of hemoglobin to enhance supplies of oxygen in cells, for use in chemical reactions requiring oxygen, as additive to serum to increase transport of oxygen, and for binding and separating oxygen from mixtures of gases.

  16. Controlling Growth Rates of Protein Samples

    NASA Technical Reports Server (NTRS)

    Herrmann, Frederick T.; Herren, Blair J.

    1987-01-01

    Apparatus enables control of humidity in chamber to control rates of growth of crystalline samples of protein. Size of drop of solution from which protein is grown made larger or smaller by condensation or evaporation of water. Situated between desiccant and water source, drop of protein solution shrinks or swells, according to which valve operator opens. Growing protein crystal viewed through polarizing film. Readily adapted to automation.

  17. Controlling Growth Rates of Protein Samples

    NASA Technical Reports Server (NTRS)

    Herrmann, Frederick T.; Herren, Blair J.

    1987-01-01

    Apparatus enables control of humidity in chamber to control rates of growth of crystalline samples of protein. Size of drop of solution from which protein is grown made larger or smaller by condensation or evaporation of water. Situated between desiccant and water source, drop of protein solution shrinks or swells, according to which valve operator opens. Growing protein crystal viewed through polarizing film. Readily adapted to automation.

  18. Meniscus Imaging for Crystal-Growth Control

    NASA Technical Reports Server (NTRS)

    Sachs, E. M.

    1983-01-01

    Silicon crystal growth monitored by new video system reduces operator stress and improves conditions for observation and control of growing process. System optics produce greater magnification vertically than horizontally, so entire meniscus and melt is viewed with high resolution in both width and height dimensions.

  19. Stromal influences on breast cancer cell growth.

    PubMed Central

    van Roozendaal, C. E.; van Ooijen, B.; Klijn, J. G.; Claassen, C.; Eggermont, A. M.; Henzen-Logmans, S. C.; Foekens, J. A.

    1992-01-01

    Paracrine influences from fibroblasts derived from different sources of breast tissue on epithelial breast cancer cell growth in vitro were investigated. Medium conditioned (CM) by fibroblasts derived from tumours, adjacent normal breast tissue, and normal breast tissue obtained from reduction mammoplasty or from skin tissue significantly stimulated the growth of the steroid-receptor positive cell lines MCF-7 and ZR 75.1. The proliferation index (PI) on MCF-7 cells with CM from fibroblasts derived from breast tumour tissue was significantly higher than that obtained with fibroblasts derived from adjacent normal breast tissue (2p less than 0.05, n = 8). The PI obtained with CM from normal fibroblast cultures from reduction mammoplasty tissue, like normal tissue adjacent to the tumour, fell in the lower range of values. Skin fibroblast, like tumour tissue derived fibroblast, CM caused a high range PI. MDA-MB-231 and Evsa-T, two steroid-receptor negative cell lines, showed only a minor growth stimulatory responses with some of the fibroblast CM's. Evsa-T was occasionally inhibited by CM's. In conclusion, stromal factors play a role in the growth regulation of human breast cancer cells. The effects on cancer cell growth are, however, varying depending on the source of the stroma and the characteristics of the epithelial tumour cells. PMID:1733444

  20. Growth rate control of flagellar assembly in Escherichia coli strain RP437

    PubMed Central

    Sim, Martin; Koirala, Santosh; Picton, David; Strahl, Henrik; Hoskisson, Paul A.; Rao, Christopher V.; Gillespie, Colin S.; Aldridge, Phillip D.

    2017-01-01

    The flagellum is a rotary motor that enables bacteria to swim in liquids and swarm over surfaces. Numerous global regulators control flagellar assembly in response to cellular and environmental factors. Previous studies have also shown that flagellar assembly is affected by the growth-rate of the cell. However, a systematic study has not yet been described under controlled growth conditions. Here, we investigated the effect of growth rate on flagellar assembly in Escherichia coli using steady-state chemostat cultures where we could precisely control the cell growth-rate. Our results demonstrate that flagellar abundance correlates with growth rate, where faster growing cells produce more flagella. They also demonstrate that this growth-rate dependent control occurs through the expression of the flagellar master regulator, FlhD4C2. Collectively, our results demonstrate that motility is intimately coupled to the growth-rate of the cell. PMID:28117390

  1. ROS Regulation of Polar Growth in Plant Cells1[OPEN

    PubMed Central

    Mangano, Silvina; Juárez, Silvina Paola Denita

    2016-01-01

    Root hair cells and pollen tubes, like fungal hyphae, possess a typical tip or polar cell expansion with growth limited to the apical dome. Cell expansion needs to be carefully regulated to produce a correct shape and size. Polar cell growth is sustained by oscillatory feedback loops comprising three main components that together play an important role regulating this process. One of the main components are reactive oxygen species (ROS) that, together with calcium ions (Ca2+) and pH, sustain polar growth over time. Apoplastic ROS homeostasis controlled by NADPH oxidases as well as by secreted type III peroxidases has a great impact on cell wall properties during cell expansion. Polar growth needs to balance a focused secretion of new materials in an extending but still rigid cell wall in order to contain turgor pressure. In this review, we discuss the gaps in our understanding of how ROS impact on the oscillatory Ca2+ and pH signatures that, coordinately, allow root hair cells and pollen tubes to expand in a controlled manner to several hundred times their original size toward specific signals. PMID:27208283

  2. ROS Regulation of Polar Growth in Plant Cells.

    PubMed

    Mangano, Silvina; Juárez, Silvina Paola Denita; Estevez, José M

    2016-07-01

    Root hair cells and pollen tubes, like fungal hyphae, possess a typical tip or polar cell expansion with growth limited to the apical dome. Cell expansion needs to be carefully regulated to produce a correct shape and size. Polar cell growth is sustained by oscillatory feedback loops comprising three main components that together play an important role regulating this process. One of the main components are reactive oxygen species (ROS) that, together with calcium ions (Ca(2+)) and pH, sustain polar growth over time. Apoplastic ROS homeostasis controlled by NADPH oxidases as well as by secreted type III peroxidases has a great impact on cell wall properties during cell expansion. Polar growth needs to balance a focused secretion of new materials in an extending but still rigid cell wall in order to contain turgor pressure. In this review, we discuss the gaps in our understanding of how ROS impact on the oscillatory Ca(2+) and pH signatures that, coordinately, allow root hair cells and pollen tubes to expand in a controlled manner to several hundred times their original size toward specific signals. © 2016 American Society of Plant Biologists. All Rights Reserved.

  3. Perception and regulatory principles of microbial growth control.

    PubMed

    Khonsari, Armin S; Kollmann, Markus

    2015-01-01

    Fast growth represents an effective strategy for microbial organisms to survive in competitive environments. To accomplish this task, cells must adapt their metabolism to changing nutrient conditions in a way that maximizes their growth rate. However, the regulation of the growth related metabolic pathways can be fundamentally different among microbes. We therefore asked whether growth control by perception of the cell's intracellular metabolic state can give rise to higher growth than by direct perception of extracellular nutrient availability. To answer this question, we created a simplified dynamical computer model of a cellular metabolic network whose regulation was inferred by an optimization approach. We used this model for a competing species experiment, where a species with extracellular nutrient perception competes against one with intracellular nutrient perception by evaluating their respective average growth rate. We found that the intracellular perception is advantageous under situations where the up and down regulation of pathways cannot follow the fast changing nutrient availability in the environment. In this case, optimal regulation ignores any other nutrients except the most preferential ones, in agreement with the phenomenon of catabolite repression in prokaryotes. The corresponding metabolic pathways remain activated, despite environmental fluctuations. Therefore, the cell can take up preferential nutrients as soon as they are available without any prior regulation. As a result species that rely on intracellular perception gain a relevant fitness advantage in fluctuating nutrient environments, which enables survival by outgrowing competitors.

  4. Brain May Prime Metastatic Cell Growth.

    PubMed

    2016-01-01

    Metastasizing tumor cells lose expression of the tumor suppressor PTEN at a much higher rate when they enter the brain compared to other organs, suggesting that the brain's unique microenvironment may prime metastatic cells for aggressive growth, a recent study reports. The findings may have implications for developing targeted therapies for brain metastases. ©2015 American Association for Cancer Research.

  5. Mitochondrial respiratory control is lost during growth factor deprivation

    PubMed Central

    Gottlieb, Eyal; Armour, Sean M.; Thompson, Craig B.

    2002-01-01

    The ability of cells to maintain a bioenergetically favorable ATP/ADP ratio confers a tight balance between cellular events that consume ATP and the rate of ATP production. However, after growth factor withdrawal, the cellular ATP/ADP ratio declines. To investigate these changes, mitochondria from growth factor-deprived cells isolated before the onset of apoptosis were characterized in vitro. Mitochondria from growth factor-deprived cells have lost their ability to undergo matrix condensation in response to ADP, which is accompanied by a failure to perform ADP-coupled respiration. At the time of analysis, mitochondria from growth factor-deprived cells were not depleted of cytochrome c and cytochrome c-dependent respiration was unaffected, demonstrating that the inhibition of the respiratory rate is not due to loss of cytochrome c. Agents that disrupt the mitochondrial outer membrane, such as digitonin, or maintain outer membrane exchange of adenine nucleotide, such as Bcl-xL, restored ADP-dependent control of mitochondrial respiration. Together, these data suggest that the regulation of mitochondrial outer membrane permeability contributes to respiratory control. PMID:12228733

  6. Amygdalin inhibits the growth of renal cell carcinoma cells in vitro.

    PubMed

    Juengel, Eva; Thomas, Anita; Rutz, Jochen; Makarevic, Jasmina; Tsaur, Igor; Nelson, Karen; Haferkamp, Axel; Blaheta, Roman A

    2016-02-01

    Although amygdalin is used by many cancer patients as an antitumor agent, there is a lack of information on the efficacy and toxicity of this natural compound. In the present study, the inhibitory effect of amygdalin on the growth of renal cell carcinoma (RCC) cells was examined. Amygdalin (10 mg/ml) was applied to the RCC cell lines, Caki-1, KTC-26 and A498, for 24 h or 2 weeks. Untreated cells served as controls. Tumor cell growth and proliferation were determined using MTT and BrdU tests, and cell cycle phases were evaluated. Expression of the cell cycle activating proteins cdk1, cdk2, cdk4, cyclin A, cyclin B, cyclin D1 and D3 as well as of the cell cycle inhibiting proteins p19 and p27 was examined by western blot analysis. Surface expression of the differentiation markers E- and N-cadherin was also investigated. Functional blockade by siRNA was used to determine the impact of several proteins on tumor cell growth. Amygdalin treatment caused a significant reduction in RCC cell growth and proliferation. This effect was correlated with a reduced percentage of G2/M-phase RCC cells and an increased percentage of cells in the G0/1-phase (Caki-1 and A498) or cell cycle arrest in the S-phase (KTC-26). Furthermore, amygdalin induced a marked decrease in cell cycle activating proteins, in particular cdk1 and cyclin B. Functional blocking of cdk1 and cyclin B resulted in significantly diminished tumor cell growth in all three RCC cell lines. Aside from its inhibitory effects on growth, amygdalin also modulated the differentiation markers, E- and N-cadherin. Hence, exposing RCC cells to amygdalin inhibited cell cycle progression and tumor cell growth by impairing cdk1 and cyclin B expression. Moreover, we noted that amygdalin affected differentiation markers. Thus, we suggest that amygdalin exerted RCC antitumor effects in vitro.

  7. Sulf1A and HGF regulate satellite-cell growth

    PubMed Central

    Gill, Roop; Hitchins, Laura; Fletcher, Fenella; Dhoot, Gurtej K.

    2010-01-01

    The role of Sulf1A, sulfation and hepatocyte growth factor (HGF) in satellite-cell growth was examined in an in vitro model of dissociated whole skeletal muscle fibres. Pax7-positive quiescent satellite cells express little or no Sulf1A but show rapid re-expression in regenerating myoblasts and myotubes, similar to embryonic muscle and in vitro satellite cells preceding asynchronous MyoD activation. Once activated, Sulf1A and MyoD re-expression persists up to 72 hours in most satellite cells under normal culture conditions and following moderate changes in sulfation, whereas Sulf1A neutralisation by antibodies not only enhances satellite-cell proliferation but also downregulates MyoD and Pax7 expression in a large proportion of the satellite cells. The HGF exposure also induces similar but even more pronounced changes characterised by variable sulfation levels and rapid downregulation of MyoD and Pax7 without myogenin activation in a sub-set of cells. This Pax7-MyoD-myogenin-negative sub-population expresses Sulf1A and Myf5. The transfer of all such satellite-cell progenies onto gelatin-coated-substratum re-activates MyoD and Pax7 gene expression in all cells, thus detecting a distinct sub-population of satellite cells. We conclude that HGF and fine-tuned sulfation levels are major contributory factors controlling satellite-cell growth by regulating the relative activities of actively proliferating and differentiating cells. PMID:20442248

  8. Learning-related synaptic growth mediated by internalization of Aplysia cell adhesion molecule is controlled by membrane phosphatidylinositol 4,5-bisphosphate synthetic pathway.

    PubMed

    Lee, Seung-Hee; Shim, Jaehoon; Choi, Sun-Lim; Lee, Nuribalhae; Lee, Chang-Hoon; Bailey, Craig H; Kandel, Eric R; Jang, Deok-Jin; Kaang, Bong-Kiun

    2012-11-14

    Long-term facilitation in Aplysia is accompanied by the growth of new synaptic connections between the sensory and motor neurons of the gill-withdrawal reflex. One of the initial steps leading to the growth of these synapses is the internalization, induced by 5-HT, of the transmembrane isoform of Aplysia cell-adhesion molecule (TM-apCAM) from the plasma membrane of sensory neurons (Bailey et al., 1992). However, the mechanisms that govern the internalization of TM-apCAM and how this internalization is coupled to the molecular events that initiate the structural changes are not fully understood. Here, we report that the synthesis of membrane phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)], which is known to be mediated by a signaling cascade through Aplysia Sec7 protein (ApSec7) and phosphatidylinositol-4-phosphate 5-kinase type I α (PIP5KIα) is required for both the internalization of TM-apCAM and the initiation of synaptic growth during 5-HT-induced long-term facilitation. Pharmacological blockade of PI(4,5)P(2) synthesis by the application of the inhibitor phenylarsine oxide blocked the internalization of apCAM. Furthermore, perturbation of the endogenous activation of ApSec7 and its downstream target PIP5KIα also blocked 5-HT-mediated internalization of TM-apCAM and synaptic growth. Finally, long-term facilitation was specifically impaired by blocking the ApSec7 signaling pathway at sensory-to-motor neuron synapses. These data indicate that the ApSec7/PIP5KIα signaling pathway is actively recruited during learning-related 5-HT signaling and acts as a key regulator of apCAM internalization associated with the formation of new synaptic connections during long-term facilitation.

  9. Mitogen-activated protein kinase 6 controls root growth in Arabidopsis by modulating Ca2+ -based Na+ flux in root cell under salt stress.

    PubMed

    Han, Shuan; Wang, Chi-wen; Wang, Wen-le; Jiang, Jing

    2014-03-01

    Little is known about the role of mitogen-activated protein kinase 6 (MPK6) in Na(+) toxicity and inhibition of root growth in Arabidopsis under NaCl stress. In this study, we found that root elongation in seedlings of the loss-of-function mutants mpk6-2 and mpk6-3 was less sensitive to NaCl or Na-glutamate, but not to KCl or mannitol, as compared with that of wild-type (WT) seedlings. The less sensitive characteristic was eliminated by adding the Ca(2+) chelator EGTA or the Ca(2+) channel inhibitor LaCl3, but not the Ca(2+) ionophore A23187. This suggested that the tolerance of mpk6 to Na(+) toxicity was Ca(2+)-dependent. We measured plasma membrane (PM) Na(+)-conducted currents (NCCs) in root cells. Increased concentrations of NaCl increased the inward NCCs while decreased the outward NCCs in WT root cells, attended by a positive shift in membrane potential. In mpk6 root cells, NaCl significantly increased outward but not inward NCCs, accompanied by a negative shift in membrane potential. That is, mpk6 decreased NaCl-induced the Na(+) accumulation by modifying PM Na(+) flux in root cells. Observations of aequorin luminescence revealed a NaCl-induced increase of cytosolic Ca(2+) in mpk6 root cells, resulting from PM Ca(2+) influx. An increase of cytosolic Ca(2+) was required to alleviate the NaCl-increased Na(+) content and Na(+)/K(+) ratio in mpk6 roots. Together, these results show that mpk6 accumulated less Na(+) in response to NaCl because of the increased cytosolic Ca(2+) level in root cells; thus, its root elongation was less inhibited than that of WT by NaCl.

  10. Cell metabolism: an essential link between cell growth and apoptosis

    PubMed Central

    Mason, Emily F.; Rathmell, Jeffrey C.

    2010-01-01

    Growth factor-stimulated or cancerous cells require sufficient nutrients to meet the metabolic demands of cell growth and division. If nutrients are insufficient, metabolic checkpoints are triggered that lead to cell cycle arrest and the activation of the intrinsic apoptotic cascade through a process dependent on the Bcl-2 family of proteins. Given the connections between metabolism and apoptosis, the notion of targeting metabolism to induce cell death in cancer cells has recently garnered much attention. However, the signaling pathways by which metabolic stresses induce apoptosis have not as of yet been fully elucidated. Thus, the best approach to this promising therapeutic avenue remains unclear. This review will discuss the intricate links between metabolism, growth, and intrinsic apoptosis and will consider ways in which manipulation of metabolism might be exploited to promote apoptotic cell death in cancer cells. PMID:20816705

  11. Size sensors in bacteria, cell cycle control, and size control

    PubMed Central

    Robert, Lydia

    2015-01-01

    Bacteria proliferate by repetitive cycles of cellular growth and division. The progression into the cell cycle is admitted to be under the control of cell size. However, the molecular basis of this regulation is still unclear. Here I will discuss which mechanisms could allow coupling growth and division by sensing size and transmitting this information to the division machinery. Size sensors could act at different stages of the cell cycle. During septum formation, mechanisms controlling the formation of the Z ring, such as MinCD inhibition or Nucleoid Occlusion (NO) could participate in the size-dependence of the division process. In addition or alternatively, the coupling of growth and division may occur indirectly through the control of DNA replication initiation. The relative importance of these different size-sensing mechanisms could depend on the environmental and genetic context. The recent demonstration of an incremental strategy of size control in bacteria, suggests that DnaA-dependent control of replication initiation could be the major size control mechanism limiting cell size variation. PMID:26074903

  12. Size sensors in bacteria, cell cycle control, and size control.

    PubMed

    Robert, Lydia

    2015-01-01

    Bacteria proliferate by repetitive cycles of cellular growth and division. The progression into the cell cycle is admitted to be under the control of cell size. However, the molecular basis of this regulation is still unclear. Here I will discuss which mechanisms could allow coupling growth and division by sensing size and transmitting this information to the division machinery. Size sensors could act at different stages of the cell cycle. During septum formation, mechanisms controlling the formation of the Z ring, such as MinCD inhibition or Nucleoid Occlusion (NO) could participate in the size-dependence of the division process. In addition or alternatively, the coupling of growth and division may occur indirectly through the control of DNA replication initiation. The relative importance of these different size-sensing mechanisms could depend on the environmental and genetic context. The recent demonstration of an incremental strategy of size control in bacteria, suggests that DnaA-dependent control of replication initiation could be the major size control mechanism limiting cell size variation.

  13. Cancer Cells Hijack Gluconeogenic Enzymes to Fuel Cell Growth.

    PubMed

    Balsa-Martinez, Eduardo; Puigserver, Pere

    2015-11-19

    In this issue and the October 15th issue of Molecular Cell, studies by Montal et al. (2015) and Vincent et al. (2015) report that certain types of cancer cells utilize the gluconeogenic enzymes phosphoenolpyruvate carboxykinase (PEPCK) and phosphoenolpyruvate carboxykinase 2 (PCK2) to reprogram anabolic metabolism and support cell growth.

  14. [Feedback control mechanisms of plant cell expansion

    SciTech Connect

    Cosgrove, D.J.

    1992-01-01

    We have generated considerable evidence for the significance of wall stress relaxation in the control of plant growth and found that several agents (gibberellin, light, genetic loci for dwarf stature) influence growth rate via alteration of wall relaxation. We have refined our methods for measuring wall relaxation and, moreover, have found that wall relaxation properties bear only a distance relationship to wall mechanical properties. We have garnered novel insights into the nature of cell expansion mechanisms by analyzing spontaneous fluctuations of plant growth rate in seedlings. These experiments involved the application of mathematical techniques for analyzing growth rate fluctuations and the development of new instrumentation for measuring and forcing plant growth in a controlled fashion. These studies conclude that growth rate fluctuations generated by the plant as consequence of a feedback control system. This conclusion has important implications for the nature of wall loosening processes and demands a different framework for thinking about growth control. It also implies the existence of a growth rate sensor.

  15. Cell shape, cytoskeletal mechanics, and cell cycle control in angiogenesis

    NASA Technical Reports Server (NTRS)

    Ingber, D. E.; Prusty, D.; Sun, Z.; Betensky, H.; Wang, N.

    1995-01-01

    Capillary endothelial cells can be switched between growth and differentiation by altering cell-extracellular matrix interactions and thereby, modulating cell shape. Studies were carried out to determine when cell shape exerts its growth-regulatory influence during cell cycle progression and to explore the role of cytoskeletal structure and mechanics in this control mechanism. When G0-synchronized cells were cultured in basic fibroblast growth factor (FGF)-containing defined medium on dishes coated with increasing densities of fibronectin or a synthetic integrin ligand (RGD-containing peptide), cell spreading, nuclear extension, and DNA synthesis all increased in parallel. To determine the minimum time cells must be adherent and spread on extracellular matrix (ECM) to gain entry into S phase, cells were removed with trypsin or induced to retract using cytochalasin D at different times after plating. Both approaches revealed that cells must remain extended for approximately 12-15 h and hence, most of G1, in order to enter S phase. After this restriction point was passed, normally 'anchorage-dependent' endothelial cells turned on DNA synthesis even when round and in suspension. The importance of actin-containing microfilaments in shape-dependent growth control was confirmed by culturing cells in the presence of cytochalasin D (25-1000 ng ml-1): dose-dependent inhibition of cell spreading, nuclear extension, and DNA synthesis resulted. In contrast, induction of microtubule disassembly using nocodazole had little effect on cell or nuclear spreading and only partially inhibited DNA synthesis. Interestingly, combination of nocodazole with a suboptimal dose of cytochalasin D (100 ng ml-1) resulted in potent inhibition of both spreading and growth, suggesting that microtubules are redundant structural elements which can provide critical load-bearing functions when microfilaments are partially compromised. Similar synergism between nocodazole and cytochalasin D was observed

  16. Cell shape, cytoskeletal mechanics, and cell cycle control in angiogenesis

    NASA Technical Reports Server (NTRS)

    Ingber, D. E.; Prusty, D.; Sun, Z.; Betensky, H.; Wang, N.

    1995-01-01

    Capillary endothelial cells can be switched between growth and differentiation by altering cell-extracellular matrix interactions and thereby, modulating cell shape. Studies were carried out to determine when cell shape exerts its growth-regulatory influence during cell cycle progression and to explore the role of cytoskeletal structure and mechanics in this control mechanism. When G0-synchronized cells were cultured in basic fibroblast growth factor (FGF)-containing defined medium on dishes coated with increasing densities of fibronectin or a synthetic integrin ligand (RGD-containing peptide), cell spreading, nuclear extension, and DNA synthesis all increased in parallel. To determine the minimum time cells must be adherent and spread on extracellular matrix (ECM) to gain entry into S phase, cells were removed with trypsin or induced to retract using cytochalasin D at different times after plating. Both approaches revealed that cells must remain extended for approximately 12-15 h and hence, most of G1, in order to enter S phase. After this restriction point was passed, normally 'anchorage-dependent' endothelial cells turned on DNA synthesis even when round and in suspension. The importance of actin-containing microfilaments in shape-dependent growth control was confirmed by culturing cells in the presence of cytochalasin D (25-1000 ng ml-1): dose-dependent inhibition of cell spreading, nuclear extension, and DNA synthesis resulted. In contrast, induction of microtubule disassembly using nocodazole had little effect on cell or nuclear spreading and only partially inhibited DNA synthesis. Interestingly, combination of nocodazole with a suboptimal dose of cytochalasin D (100 ng ml-1) resulted in potent inhibition of both spreading and growth, suggesting that microtubules are redundant structural elements which can provide critical load-bearing functions when microfilaments are partially compromised. Similar synergism between nocodazole and cytochalasin D was observed

  17. Growth of Cu2ZnSnSe4 Film under Controllable Se Vapor Composition and Impact of Low Cu Content on Solar Cell Efficiency.

    PubMed

    Li, Jianjun; Wang, Hongxia; Wu, Li; Chen, Cheng; Zhou, Zhiqiang; Liu, Fangfang; Sun, Yun; Han, Junbo; Zhang, Yi

    2016-04-27

    It is a challenge to fabricate high quality Cu2ZnSnSe4 (CZTSe) film with low Cu content (Cu/(Zn + Sn) < 0.8). In this work, the growth mechanisms of CZTSe films under different Se vapor composition are investigated by DC-sputtering and a postselenization approach. The composition of Se vapor has important influence on the compactability of the films and the diffusion of elements in the CZTSe films. By adjusting the composition of Se vapor during the selenization process, an optimized two step selenization process is proposed and highly crystallized CZTSe film with low Cu content (Cu/(Zn + Sn) = 0.75) is obtained. Further study of the effect of Cu content on the morphology and photovoltaic performance of the corresponding CZTSe solar cells has shown that the roughness of the CZTSe absorber film increases when Cu content decreases. As a consequence, the reflection loss of CZTSe solar cells reduces dramatically and the short circuit current density of the cells improve from 34.7 mA/cm(2) for Cu/(Zn + Sn) = 0.88 to 38.5 mA/cm(2) for Cu/(Zn + Sn) = 0.75. In addition, the CZTSe solar cells with low Cu content show longer minority carrier lifetime and higher open circuit voltage than the high Cu content devices. A champion performance CZTSe solar cell with 10.4% efficiency is fabricated with Cu/(Zn + Sn) = 0.75 in the CZTSe film without antireflection coating.

  18. Differential control of growth, apoptotic activity and gene expression in human colon cancer cells by extracts derived from medicinal herbs, Rhazya stricta and Zingiber officinale and their combination

    PubMed Central

    Elkady, Ayman I; Hussein, Rania Abd El Hamid; Abu-Zinadah, Osama A

    2014-01-01

    AIM: To investigate the effects of extracts from Rhazya stricta (R. stricta) and Zingiber officinale (Z. officinale) on human colorectal cancer cells. METHODS: Human colorectal cancer cells (HCT116) were subjected to increasing doses of crude alkaloid extracts from R. stricta (CAERS) and crude flavonoid extracts from Z. officinale (CFEZO). Cells were then harvested after 24, 48 or 72 h and cell viability was examined by trypan blue exclusion dye test; clonogenicity and soft agar colony-forming assays were also carried out. Nuclear stain (Hoechst 33342), acridine orange/ethidium bromide double staining, agarose gel electrophoresis and comet assays were performed to assess pro-apoptotic potentiality of the extracts. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR), using gene-specific primers and Western blot analyses were performed to assess the impact of CAERS and CFEZO on the expression levels of key regulatory proteins in HCT116 cells. RESULTS: Treatment with a combination of CAERS and CFEZO synergistically suppressed the proliferation, colony formation and anchorage-independent growth of HCT116 cells. Calculated IC50, after 24, 48 and 72 h, were 70, 90 and 130 μg/mL for CAERS, 65, 85 and 120 μg/mL for CFEZO and 20, 25 and 45 μg/mL for both agents, respectively. CAERS- and CFEZO-treated cells exhibited morphologic and biochemical features of apoptotic cell death. The induction of apoptosis was associated with the release of mitochondrial cytochrome c, an increase in the Bax/Bcl-2 ratio, activation of caspases 3 and 9 and cleavage of poly ADP-ribose polymerase. CAERS and CFEZO treatments downregulated expression levels of anti-apoptotic proteins including Bcl-2, Bcl-X, Mcl-1, survivin and XIAP, and upregulated expression levels of proapoptotic proteins such as Bad and Noxa. CAERS and CFEZO treatments elevated expression levels of the oncosuppressor proteins, p53, p21 and p27, and reduced levels of the oncoproteins, cyclin D1, cyclin

  19. Vapor Crystal Growth (VCG) experiment Cell

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The image shows a test cell of Crystal Growth experiment inside the Vapor Crystal Growth System (VCGS) furnace aboard the STS-42, International Microgravity Laboratory-1 (IML-1), mission. The goal of IML-1, a pressurized marned Spacelab module, was to explore in depth the complex effects of weightlessness of living organisms and materials processing. More than 200 scientists from 16 countires participated in the investigations.

  20. Circulating Fibronectin Controls Tumor Growth12

    PubMed Central

    von Au, Anja; Vasel, Matthaeus; Kraft, Sabrina; Sens, Carla; Hackl, Norman; Marx, Alexander; Stroebel, Philipp; Hennenlotter, Jörg; Todenhöfer, Tilman; Stenzl, Arnulf; Schott, Sarah; Sinn, Hans-Peter; Wetterwald, Antoinette; Bermejo, Justo Lorenzo; Cecchini, Marco G; Nakchbandi, Inaam A

    2013-01-01

    Fibronectin is ubiquitously expressed in the extracellular matrix, and experimental evidence has shown that it modulates blood vessel formation. The relative contribution of local and circulating fibronectin to blood vessel formation in vivo remains unknown despite evidence for unexpected roles of circulating fibronectin in various diseases. Using transgenic mouse models, we established that circulating fibronectin facilitates the growth of bone metastases by enhancing blood vessel formation and maturation. This effect is more relevant than that of fibronectin produced by endothelial cells and pericytes, which only exert a small additive effect on vessel maturation. Circulating fibronectin enhances its local production in tumors through a positive feedback loop and increases the amount of vascular endothelial growth factor (VEGF) retained in the matrix. Both fibronectin and VEGF then cooperate to stimulate blood vessel formation. Fibronectin content in the tumor correlates with the number of blood vessels and tumor growth in the mouse models. Consistent with these results, examination of three separate arrays from patients with breast and prostate cancers revealed that a high staining intensity for fibronectin in tumors is associated with increased mortality. These results establish that circulating fibronectin modulates blood vessel formation and tumor growth by modifying the amount of and the response to VEGF. Furthermore, determination of the fibronectin content can serve as a prognostic biomarker for breast and prostate cancers and possibly other cancers. PMID:23908593

  1. Optimization of processing parameters on the controlled growth of ZnO nanorod arrays for the performance improvement of solid-state dye-sensitized solar cells

    SciTech Connect

    Lee, Yi-Mu; Yang, Hsi-Wen

    2011-03-15

    High-transparency and high quality ZnO nanorod arrays were grown on the ITO substrates by a two-step chemical bath deposition (CBD) method. The effects of processing parameters including reaction temperature (25-95 {sup o}C) and solution concentration (0.01-0.1 M) on the crystal growth, alignment, optical and electrical properties were systematically investigated. It has been found that these process parameters are critical for the growth, orientation and aspect ratio of the nanorod arrays, showing different structural and optical properties. Experimental results reveal that the hexagonal ZnO nanorod arrays prepared under reaction temperature of 95 {sup o}C and solution concentration of 0.03 M possess highest aspect ratio of {approx}21, and show the well-aligned orientation and optimum optical properties. Moreover the ZnO nanorod arrays based heterojunction electrodes and the solid-state dye-sensitized solar cells (SS-DSSCs) were fabricated with an improved optoelectrical performance. -- Graphical abstract: The ZnO nanorod arrays demonstrate well-alignment, high aspect ratio (L/D{approx}21) and excellent optical transmittance by low-temperature chemical bath deposition (CBD). Display Omitted Research highlights: > Investigate the processing parameters of CBD on the growth of ZnO nanorod arrays. > Optimization of CBD process parameters: 0.03 M solution concentration and reaction temperature of 95 {sup o}C. > The prepared ZnO samples possess well-alignment and high aspect ratio (L/D{approx}21). > An n-ZnO/p-NiO heterojunction: great rectifying behavior and low leakage current. > SS-DSSC has J{sub SC} of 0.31 mA/cm{sup 2} and V{sub OC} of 590 mV, and an improved {eta} of 0.059%.

  2. Allyl sulfides modify cell growth.

    PubMed

    Knowles, L M; Milner, J A

    2000-01-01

    Extensive evidence points to the ability of allyl sulfides from garlic to suppress tumor proliferation both in vitro and in vivo. This antineoplastic effect is generally greater for lipid-soluble than water-soluble allyl sulfides. Both concentration and duration of exposure can increase the antiproliferative effects of lipid- and water-soluble allyl sulfides. Part of their antiproliferative effects may relate to an increase in membrane fluidity and a suppression of integrin glycoprotein IIb-IIIa mediated adhesion. Alterations in cholesterol, arachidonic acid, phospholipids and/or thiols may account for these changes in membrane function. Allyl sulfides are also recognized for their ability to suppress cellular proliferation by blocking cells in the G2/M phase and by the induction of apoptosis. This increase in the G2/M and apoptotic cell populations correlates with depressed p34cdc2 kinase activity, increased histone acetylation, increased intracellular calcium and elevated cellular peroxide production. While impressive pre-clinical data exist about the antineoplastic effects of allyl sulfur compounds, considerably more attention needs to be given to their effects in humans. The composition of the entire diet and a host of genetic/epigenetic factors will likely determine the true benefits that might arise from allyl sulfur compounds from garlic and other Allium foods.

  3. Colloidal Gold--Collagen Protein Core--Shell Nanoconjugate: One-Step Biomimetic Synthesis, Layer-by-Layer Assembled Film, and Controlled Cell Growth.

    PubMed

    Xing, Ruirui; Jiao, Tifeng; Yan, Linyin; Ma, Guanghui; Liu, Lei; Dai, Luru; Li, Junbai; Möhwald, Helmuth; Yan, Xuehai

    2015-11-11

    The biogenic synthesis of biomolecule-gold nanoconjugates is of key importance for a broad range of biomedical applications. In this work, a one-step, green, and condition-gentle strategy is presented to synthesize stable colloidal gold-collagen core-shell nanoconjugates in an aqueous solution at room temperature, without use of any reducing agents and stabilizing agents. It is discovered that electrostatic binding between gold ions and collagen proteins and concomitant in situ reduction by hydroxyproline residues are critically responsible for the formation of the core-shell nanoconjugates. The film formed by layer-by-layer assembly of such colloidal gold-collagen nanoconjugates can notably improve the mechanical properties and promote cell adhesion, growth, and differentiation. Thus, the colloidal gold-collagen nanoconjugates synthesized by such a straightforward and clean manner, analogous to a biomineralization pathway, provide new alternatives for developing biologically based hybrid biomaterials toward a range of therapeutic and diagnostic applications.

  4. MicroRNA-29a in Adult Muscle Stem Cells Controls Skeletal Muscle Regeneration During Injury and Exercise Downstream of Fibroblast Growth Factor-2.

    PubMed

    Galimov, Artur; Merry, Troy L; Luca, Edlira; Rushing, Elisabeth J; Mizbani, Amir; Turcekova, Katarina; Hartung, Angelika; Croce, Carlo M; Ristow, Michael; Krützfeldt, Jan

    2016-03-01

    The expansion of myogenic progenitors (MPs) in the adult muscle stem cell niche is critical for the regeneration of skeletal muscle. Activation of quiescent MPs depends on the dismantling of the basement membrane and increased access to growth factors such as fibroblast growth factor-2 (FGF2). Here, we demonstrate using microRNA (miRNA) profiling in mouse and human myoblasts that the capacity of FGF2 to stimulate myoblast proliferation is mediated by miR-29a. FGF2 induces miR-29a expression and inhibition of miR-29a using pharmacological or genetic deletion decreases myoblast proliferation. Next generation RNA sequencing from miR-29a knockout myoblasts (Pax7(CE/+) ; miR-29a(flox/flox) ) identified members of the basement membrane as the most abundant miR-29a targets. Using gain- and loss-of-function experiments, we confirm that miR-29a coordinately regulates Fbn1, Lamc1, Nid2, Col4a1, Hspg2 and Sparc in myoblasts in vitro and in MPs in vivo. Induction of FGF2 and miR-29a and downregulation of its target genes precedes muscle regeneration during cardiotoxin (CTX)-induced muscle injury. Importantly, MP-specific tamoxifen-induced deletion of miR-29a in adult skeletal muscle decreased the proliferation and formation of newly formed myofibers during both CTX-induced muscle injury and after a single bout of eccentric exercise. Our results identify a novel miRNA-based checkpoint of the basement membrane in the adult muscle stem cell niche. Strategies targeting miR-29a might provide useful clinical approaches to maintain muscle mass in disease states such as ageing that involve aberrant FGF2 signaling.

  5. The integration of cell division, growth and differentiation.

    PubMed

    Harashima, Hirofumi; Schnittger, Arp

    2010-02-01

    The development of a multicellular organism such as a flowering plant relies on the patterned control of cell proliferation, differentiation, and growth. Research in the recent years has revealed that the control of cell-cycle progression and growth in plants is distinct from the regulation found in yeast or metazoans. Understanding these plant-specific regulators and networks, in which they act, is key for the understanding of plant development and is of current global importance as a basis for breeding of energy crops as well as the breeding of plants adapted for changing environmental conditions. However, the production of cells and their specification and differentiation overlap in time and space and build an intricate interrelationship of dependencies and feedback loops. In this network, the developmental context and the generation of specific cell types and tissues are often decisive. Copyright 2009 Elsevier Ltd. All rights reserved.

  6. Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth

    PubMed Central

    Mollet, Jean-Claude; Leroux, Christelle; Dardelle, Flavien; Lehner, Arnaud

    2013-01-01

    The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed. PMID:27137369

  7. Regulation of rat ovarian cell growth and steroid secretion

    PubMed Central

    Johnson, CC; Dawson, WE; Turner, JT; Wyche, JH

    1980-01-01

    A cultured rat ovarian cell line (31 A-F(2)) was used to study the effect of growth factors (epidermal growth factor [EGF] and fibroblast growth factor [FGF]), a survival factor (ovarian growth factor [OGF]), a hormone (insulin), and an iron-binding protein (transferring) on cell proliferation and steroid production under defined culture conditions. EGF and insulin were shown to be mitogenic (half-maximal response at 0.12 nM and 0.11 muM, respectively) for 31A-F(2) cells incubated in serum-free medium. EGF induced up to three doublings in the cell population, whereas insulin induced an average of one cell population doubling. FGF, OGF, and transferrin were found not to have any prominent effect on cell division when incubated individually with 31A-F(2) cells in serum-free medium. However, a combination of EGF, OGF, insulin, and transferrin stimulated cell division to the same approximate extent as cells incubated in the presence of 5 percent fetal calf serum. EGF or insulin did not significantly affect total cell cholesterol levels (relative to cells incubated in serum-free medium) when incubated individually with 31A-F(2) cells. However, cell cholesterol levels were increased by the addition of OGF (250 percent), FGF (370 percent), or a combination of insulin and EGF (320 percent). Progesterone secretion from 31A-F(2) cells was enhanced by EGF (25 percent), FGF (80 percent), and insulin (115 percent). However, the addition of a mitogenic mixture of EGF, OGF, insulin, and transferrin suppressed progesterone secretion 150 percent) below that of control cultures. These studies have permitted us to determine that EGF and insulin are mitogenic factors that are required for the growth of 31A-F(2) cells and that OGF and transferrin are positive cofactors that enhance growth. Also, additional data suggest that cholesterol and progesterone production in 31A-F(2) cells can be regulated by peptide growth factors and the hormone insulin. PMID:6995465

  8. Cell size control and homeostasis in bacteria

    NASA Astrophysics Data System (ADS)

    Bradde, Serena; Taheri, Sattar; Sauls, John; Hill, Nobert; Levine, Petra; Paulsson, Johan; Vergassola, Massimo; Jun, Suckjoon

    2015-03-01

    How cells control their size is a fundamental question in biology. The mechanisms for sensing size, time, or a combination of the two are not supported by experimental evidence. By analysing distributions of size at division at birth and generation time of hundreds of thousands of Gram-negative E. coli and Gram-positive B. subtilis cells under a wide range of tightly controlled steady-state growth conditions, we are now in the position to validate different theoretical models. In this talk I will present all possible models in details and present a general mechanism that quantitatively explains all measurable aspects of growth and cell division at both population and single-cell levels.

  9. Redox control of plant growth and development.

    PubMed

    Kocsy, Gábor; Tari, Irma; Vanková, Radomíra; Zechmann, Bernd; Gulyás, Zsolt; Poór, Péter; Galiba, Gábor

    2013-10-01

    Redox changes determined by genetic and environmental factors display well-organized interactions in the control of plant growth and development. Diurnal and seasonal changes in the environmental conditions are important for the normal course of these physiological processes and, similarly to their mild irregular alterations, for stress adaptation. However, fast or large-scale environmental changes may lead to damage or death of sensitive plants. The spatial and temporal redox changes influence growth and development due to the reprogramming of metabolism. In this process reactive oxygen and nitrogen species and antioxidants are involved as components of signalling networks. The control of growth, development and flowering by reactive oxygen and nitrogen species and antioxidants in interaction with hormones at organ, tissue, cellular and subcellular level will be discussed in the present review. Unsolved problems of the field, among others the need for identification of new components and interactions in the redox regulatory network at various organization levels using systems biology approaches will be also indicated.

  10. Growth Patterns in Children with Sickle Cell Anemia during Puberty

    PubMed Central

    Rhodes, Melissa; Akohoue, Sylvie A.; Shankar, Sadhna M.; Fleming, Irma; An, Angel; Yu, Chung; Acra, Sari; Buchowski, Maciej S.

    2009-01-01

    Background Previous studies of children with homozygous sickle cell anemia (SCA) show impaired growth and maturation. The correlation of this suboptimal growth with metabolic and hematological factors during puberty is poorly understood. Procedure We studied a group of pre-adolescent children with SCA (19 males, 14 females) and healthy controls (16 males, 15 females) matched for race, sex, body size, and pubertal development. Height, weight, body mass index (BMI), and body composition changes were longitudinally assessed over a 2-year period and compared between the groups and with Z scores based on US growth charts. These changes were correlated with hemoglobin concentration and with energy expenditure measured using indirect whole-room calorimetry. Results Children with SCA progressed through puberty slower than control children. While, after 2 years, pubertal males with SCA were shorter, their annual increases in weight were not different from controls. The mean fat free mass (FFM) increments were significantly less in males and females with SCA than in control children. In males with SCA, growth in height declined over time and was significantly slower than in matched controls (p<0.05). Conclusion Growth delays were present during puberty in children with SCA. Decreased growth velocity in children with SCA was independently associated with decreased hemoglobin concentration and increased total energy expenditure. PMID:19544390

  11. Long-term control of root growth

    SciTech Connect

    Burton, F.G.; Cataldo, D.A.; Cline, J.F.; Skiens, W.E.

    1992-05-26

    A method and system for long-term control of root growth without killing the plants bearing those roots involves incorporating a 2,6-dinitroaniline in a polymer and disposing the polymer in an area in which root control is desired. This results in controlled release of the substituted aniline herbicide over a period of many years. Herbicides of this class have the property of preventing root elongation without translocating into other parts of the plant. The herbicide may be encapsulated in the polymer or mixed with it. The polymer-herbicide mixture may be formed into pellets, sheets, pipe gaskets, pipes for carrying water, or various other forms. The invention may be applied to other protection of buried hazardous wastes, protection of underground pipes, prevention of root intrusion beneath slabs, the dwarfing of trees or shrubs and other applications. The preferred herbicide is 4-difluoromethyl-N,N-dipropyl-2,6-dinitro-aniline, commonly known as trifluralin. 7 figs.

  12. Long-term control of root growth

    DOEpatents

    Burton, Frederick G.; Cataldo, Dominic A.; Cline, John F.; Skiens, W. Eugene

    1992-05-26

    A method and system for long-term control of root growth without killing the plants bearing those roots involves incorporating a 2,6-dinitroaniline in a polymer and disposing the polymer in an area in which root control is desired. This results in controlled release of the substituted aniline herbicide over a period of many years. Herbicides of this class have the property of preventing root elongation without translocating into other parts of the plant. The herbicide may be encapsulated in the polymer or mixed with it. The polymer-herbicide mixture may be formed into pellets, sheets, pipe gaskets, pipes for carrying water, or various other forms. The invention may be applied to other protection of buried hazardous wastes, protection of underground pipes, prevention of root intrusion beneath slabs, the dwarfing of trees or shrubs and other applications. The preferred herbicide is 4-difluoromethyl-N,N-dipropyl-2,6-dinitro-aniline, commonly known as trifluralin.

  13. Growth hormone induces multiplication of the slowly cycling germinal cells of the rat tibial growth plate.

    PubMed

    Ohlsson, C; Nilsson, A; Isaksson, O; Lindahl, A

    1992-10-15

    To study the effect of locally infused growth hormone (GH) or insulin-like growth factor I(IGF-I) on slowly cycling cells in the germinal cell layer of the tibial growth plate, osmotic minipumps delivering 14.3 microCi of [3H]thymidine per day were implanted s.c. into hypophysectomized rats, and GH (1 microgram) or IGF-I (10 micrograms) was injected daily through a cannula implanted in the proximal tibia. The opposite leg served as a control. After 12 days of treatment, the osmotic minipumps were removed, and three rats in each group were given GH (20 micrograms/day, s.c.) for an additional 14 days to chase the labeled cells out of the proliferative layers. Labeled cells remained in the germinal layer, in the perichondrial ring, and on the surface of the articular cartilage close to the epiphyseal plate. GH administered together with labeled thymidine significantly increased the number of labeled cells in the germinal cell layer compared to that in the control leg (ratio = 1.95 +/- 0.13), whereas IGF-I showed no stimulatory effect (ratio = 0.96 +/- 0.04). Therefore GH but not IGF-I stimulates the multiplication of the slowly cycling (label-retaining) cells in the germinal layer of the epiphyseal plate. IGF-I acts only on the proliferation of the resulting chondrocytes.

  14. Epidermal Growth Factor Receptor-PI3K Signaling Controls Cofilin Activity To Facilitate Herpes Simplex Virus 1 Entry into Neuronal Cells

    PubMed Central

    Zheng, Kai; Xiang, Yangfei; Wang, Xiao; Wang, Qiaoli; Zhong, Meigong; Wang, Shaoxiang; Wang, Xiaoyan; Fan, Jianglin; Kitazato, Kaio; Wang, Yifei

    2014-01-01

    ABSTRACT Herpes simplex virus type 1 (HSV-1) establishes latency in neurons and can cause severe disseminated infection with neurological impairment and high mortality. This neurodegeneration is thought to be tightly associated with virus-induced cytoskeleton disruption. Currently, the regulation pattern of the actin cytoskeleton and the involved molecular mechanisms during HSV-1 entry into neurons remain unclear. Here, we demonstrate that the entry of HSV-1 into neuronal cells induces biphasic remodeling of the actin cytoskeleton and an initial inactivation followed by the subsequent activation of cofilin, a member of the actin depolymerizing factor family that is critical for actin reorganization. The disruption of F-actin dynamics or the modulation of cofilin activity by mutation, knockdown, or overexpression affects HSV-1 entry efficacy and virus-mediated cell ruffle formation. Binding of the HSV-1 envelope initiates the epidermal growth factor receptor (EGFR)-phosphatidylinositide 3-kinase (PI3K) signaling pathway, which leads to virus-induced early cofilin phosphorylation and F-actin polymerization. Moreover, the extracellular signal-regulated kinase (ERK) kinase and Rho-associated, coiled-coil-containing protein kinase 1 (ROCK) are recruited as downstream mediators of the HSV-1-induced cofilin inactivation pathway. Inhibitors specific for those kinases significantly reduce the virus infectivity without affecting virus binding to the target cells. Additionally, lipid rafts are clustered to promote EGFR-associated signaling cascade transduction. We propose that HSV-1 hijacks cofilin to initiate infection. These results could promote a better understanding of the pathogenesis of HSV-1-induced neurological diseases. PMID:24425731

  15. Monocarboxylate transporter 8 in neuronal cell growth.

    PubMed

    James, S R; Franklyn, J A; Reaves, B J; Smith, V E; Chan, S Y; Barrett, T G; Kilby, M D; McCabe, C J

    2009-04-01

    Thyroid hormones are essential for the normal growth and development of the fetus, and even small alterations in maternal thyroid hormone status during early pregnancy may be associated with neurodevelopmental abnormalities in childhood. Mutations in the novel and specific thyroid hormone transporter monocarboxylate transporter 8 (MCT8) have been associated with severe neurodevelopmental impairment. However, the mechanism by which MCT8 influences neural development remains poorly defined. We have therefore investigated the effect of wild-type (WT) MCT8, and the previously reported L471P mutant, on the growth and function of human neuronal precursor NT2 cells as well as MCT8-null JEG-3 cells. HA-tagged WT MCT8 correctly localized to the plasma membrane in NT2 cells and increased T(3) uptake in both cell types. In contrast, L471P MCT8 was largely retained in the endoplasmic reticulum and displayed no T(3) transport activity. Transient overexpression of WT and mutant MCT8 proteins failed to induce endoplasmic reticular stress or apoptosis. However, MCT8 overexpression significantly repressed cell proliferation in each cell type in both the presence and absence of the active thyroid hormone T(3) and in a dose-dependent manner. In contrast, L471P MCT8 showed no such influence. Finally, small interfering RNA depletion of endogenous MCT8 resulted in increased cell survival and decreased T(3) uptake. Given that T(3) stimulated proliferation in embryonic neuronal NT2 cells, whereas MCT8 repressed cell growth, these data suggest an entirely novel role for MCT8 in addition to T(3) transport, mediated through the modulation of cell proliferation in the developing brain.

  16. Cell metabolism: Growth and environment. Volume I

    SciTech Connect

    Subramanian, T.A.V.

    1986-01-01

    This book describes: Protein metabolism in relation to secondary biosynthesis; nucleic acid metabolism in relation to growth; the spatial organization of secondary metabolism in microbial and plant cells; aflatoxin bioysynthesis; role of oxygenases in the metabolism of phenolic compounds; regulation of secondary metabolism by trace metals; and index.

  17. Netrin-4 regulates angiogenic responses and tumor cell growth

    SciTech Connect

    Nacht, Mariana; St Martin, Thia B.; Byrne, Ann; Klinger, Katherine W.; Teicher, Beverly A.; Madden, Stephen L. Jiang, Yide

    2009-03-10

    Netrin-4 is a 628 amino acid basement membrane component that promotes neurite elongation at low concentrations but inhibits neurite extension at high concentrations. There is a growing body of literature suggesting that several molecules, including netrins, are regulators of both neuronal and vascular growth. It is believed that molecules that guide neural growth and development are also involved in regulating morphogenesis of the vascular tree. Further, netrins have recently been implicated in controlling epithelial cell branching morphogenesis in the breast, lung and pancreas. Characterization of purified netrin-4 in in vitro angiogenesis assays demonstrated that netrin-4 markedly inhibits HMVEC migration and tube formation. Moreover, netrin-4 inhibits proliferation of a variety of human tumor cells in vitro. Netrin-4 has only modest effects on proliferation of endothelial and other non-transformed cells. Netrin-4 treatment results in phosphorylation changes of proteins that are known to control cell growth. Specifically, Phospho-Akt-1, Phospho-Jnk-2, and Phospho-c-Jun are reduced in tumor cells that have been treated with netrin-4. Together, these data suggest a potential role for netrin-4 in regulating tumor growth.

  18. Differential control of growth, cell cycle progression, and expression of NF-{kappa}B in human breast cancer cells MCF-7, MCF-10A, and MDA-MB-231 by ponicidin and oridonin, diterpenoids from the chinese herb Rabdosia rubescens

    SciTech Connect

    Hsieh Tzechen; Wijeratne, E. Kithsiri; Liang Jingyu; Gunatilaka, A. Leslie; Wu, Joseph M. . E-mail: Joseph_Wu@nymc.edu

    2005-11-11

    Ponicidin and oridonin are novel diterpenoids isolated from Rabdosia rubescens. We tested their effects in MCF-7 and MDA-MB-231 cells, as representing low and high invasive breast carcinoma, with normal MCF-10A cells. Clonogenicity and proliferation in MCF-7 cells were inhibited more significantly by ponicidin than oridonin, while the reverse was observed in MCF-10A cells. Ponicidin and oridonin induced S/G{sub 2}M arrest and G{sub 1}/S block in MCF-7 cells. In MCF-10A cells treated with either diterpenoid, induction of apoptosis was observed. Moreover, oridonin almost completely blocked MCF-10A progression from S to G{sub 2}/M phase; in contrast, ponicidin-treated MCF-10A cells showed no discernable changes in cell cycle phase distribution. Neither diterpenoid affected growth of MDA-MB-231 cells, at the dose range effective for MCF-7 or MCF-10A cells. Ponicidin-treated MCF-7 cells expressed reduced levels of cyclin B1, cdc2, transcription factor E2F, and Rb including phosphorylation at S780. Less pronounced effects were found in cells treated with oridonin. Neither compound altered cyclin D1 and cdk4 in MCF-7 cells. In MCF-10A cells, oridonin was more active than ponicidin in inhibiting the expression of cyclin B1, cdc2, S780-phosphorylated Rb, and E2F. To further investigate induction of apoptosis in MCF-10A cells, we measured changes in NF-{kappa}B. Decreases in p65 or p50 forms of NF-{kappa}B and its upstream regulator I-{kappa}B were found in oridonin-treated MCF-10A and not MCF-7 cells. Taken together, these results provide a mechanistic framework for the cellular effects of ponicidin and oridonin in different stage breast cancer cells.

  19. Chromogranin A transcription and gene expression in Folliculostellate (TtT/GF) cells inhibit cell growth.

    PubMed

    Stilling, Gail A; Bayliss, Jill M; Jin, Long; Zhang, Heyu; Lloyd, Ricardo V

    2005-01-01

    Folliculostellate (FS) cells are present in the anterior pituitary and have important regulatory functions including controlling hormone release from other anterior pituitary cells. FS cells do not usually express neuroendocrine genes such as chromogranin A (CgA). We analyzed transcriptional regulation and gene expression in the TtT/GF FS cell line to better understand the role of FS cells in anterior pituitary function. After transient transfection with a human (h) CgA promoter sequence linked to a luciferase reporter, there was basal level of transcriptional activity, which was two- to fourfold less than that observed in the anterior pituitary neuroendocrine cell lines HP75 and GH3. The transcriptional activity was decreased in all cell lines when a mutant hCgA promoter cyclic AMP response element (CRE) was used for transfection. Sodium butyrate treatment increased the transcriptional activity in all cell lines, but remained two- to fourfold higher in the HP75 and GH3 cell lines than in the TtT/GF cells. Stable transfection of a plasmid expressing bovine (b) CgA in the TtT/GF cells led to inhibition of cell growth as measured by 3H-thymidine incorporation, Ki-67 labeling index, and growth curve analysis. CgA protein and mRNA could be readily demonstrated in the cloned cells but not in the parental cell line or vector control cells. When the CgA expressing cloned cells were injected into SCID mice, there was a decrease in the rate of tumor growth compared to the vector control in vivo. These results indicate that the TtT/GF FS cells are fibroblast-like compared to the neuroendocrine anterior pituitary secretory cells when analyzed by transcriptional activity with a transiently transfected CgA promoter. In TtT/GF cells with a stably transfected bCgA plasmid, CgA has a direct regulatory effect on tumor cell proliferation.

  20. Cell intrinsic control of axon regeneration

    PubMed Central

    Mar, Fernando M; Bonni, Azad; Sousa, Mónica M

    2014-01-01

    Although neurons execute a cell intrinsic program of axonal growth during development, following the establishment of connections, the developmental growth capacity declines. Besides environmental challenges, this switch largely accounts for the failure of adult central nervous system (CNS) axons to regenerate. Here, we discuss the cell intrinsic control of axon regeneration, including not only the regulation of transcriptional and epigenetic mechanisms, but also the modulation of local protein translation, retrograde and anterograde axonal transport, and microtubule dynamics. We further explore the causes underlying the failure of CNS neurons to mount a vigorous regenerative response, and the paradigms demonstrating the activation of cell intrinsic axon growth programs. Finally, we present potential mechanisms to support axon regeneration, as these may represent future therapeutic approaches to promote recovery following CNS injury and disease. PMID:24531721

  1. Growth of connective tissue progenitor cells on microtextured polydimethylsiloxane surfaces.

    PubMed

    Mata, Alvaro; Boehm, Cynthia; Fleischman, Aaron J; Muschler, George; Roy, Shuvo

    2002-12-15

    Growth of human connective tissue progenitor cells (CTPs) was characterized on smooth and microtextured polydimethylsiloxane (PDMS) surfaces. Human bone-marrow-derived cells were cultured for 9 days under conditions promoting osteoblastic differentiation on smooth PDMS surfaces and on PDMS post microtextures that were 6 microm high and 5, 10, 20, and 40 microm in diameter, respectively. Glass tissue-culture dishes were used as controls. The number of viable cells was determined, and an alkaline phosphatase stain was used as a marker for osteoblastic phenotype. CTPs attached, proliferated, and differentiated on all surfaces. Cells on the smooth PDMS and control surfaces spread and proliferated as colonies in proximity to other cells and migrated in random directions, with cell process lengths of up to 80 microm. In contrast, cells on the PDMS post microtextures grew as sparsely distributed networks of cells, with processes, occasionally up to 300 microm, that appeared to interact with the posts. Cell counts revealed that there were fewer (50%) CTPs on the smooth PDMS surface than were on the glass control surfaces. However, there were consistently more (>144%) CTPs on the PDMS post textures than on the controls. In particular, the 10-microm-in-diameter posts (268%) exhibited a significantly (p < 0.05) greater cell number than did the smooth PDMS.

  2. Nuclear Ras2-GTP controls invasive growth in Saccharomyces cerevisiae.

    PubMed

    Broggi, Serena; Martegani, Enzo; Colombo, Sonia

    2013-01-01

    Using an eGFP-RBD3 probe, which specifically binds Ras-GTP, we recently showed that the fluorescent probe was localized to the plasma membrane and to the nucleus in wild type cells growing exponentially on glucose medium, indicating the presence of active Ras in these cellular compartments. To investigate the nuclear function of Ras-GTP, we generated a strain where Ras2 is fused to the nuclear export signal (NES) from the HIV virus, in order to exclude this protein from the nucleus. Our results show that nuclear active Ras2 is required for invasive growth development in haploid yeast, while the expression of the NES-Ras2 protein does not cause growth defects either on fermentable or non-fermentable carbon sources and does not influence protein kinase A (PKA) activity related phenotypes analysed. Moreover, we show that the cAMP/PKA pathway controls invasive growth influencing the localization of active Ras. In particular, we show that PKA activity plays a role in the localization of active Ras and influences the ability of the cells to invade the agar: high PKA activity leads to a predominant nuclear accumulation of active Ras and induces invasive growth, while low PKA activity leads to plasma membrane localization of active Ras and to a defective invasive growth phenotype.

  3. Nuclear Ras2-GTP Controls Invasive Growth in Saccharomyces cerevisiae

    PubMed Central

    Broggi, Serena; Martegani, Enzo; Colombo, Sonia

    2013-01-01

    Using an eGFP-RBD3 probe, which specifically binds Ras-GTP, we recently showed that the fluorescent probe was localized to the plasma membrane and to the nucleus in wild type cells growing exponentially on glucose medium, indicating the presence of active Ras in these cellular compartments. To investigate the nuclear function of Ras-GTP, we generated a strain where Ras2 is fused to the nuclear export signal (NES) from the HIV virus, in order to exclude this protein from the nucleus. Our results show that nuclear active Ras2 is required for invasive growth development in haploid yeast, while the expression of the NES-Ras2 protein does not cause growth defects either on fermentable or non-fermentable carbon sources and does not influence protein kinase A (PKA) activity related phenotypes analysed. Moreover, we show that the cAMP/PKA pathway controls invasive growth influencing the localization of active Ras. In particular, we show that PKA activity plays a role in the localization of active Ras and influences the ability of the cells to invade the agar: high PKA activity leads to a predominant nuclear accumulation of active Ras and induces invasive growth, while low PKA activity leads to plasma membrane localization of active Ras and to a defective invasive growth phenotype. PMID:24244466

  4. Promoted growth of murine hair follicles through controlled release of vascular endothelial growth factor.

    PubMed

    Ozeki, Makoto; Tabata, Yasuhiko

    2002-06-01

    The objective of this study is to investigate whether or not the controlled release of vascular endothelial growth factor (VEGF) is effective in promoting the hair follicle growth of mice in second anagen of hair cycle. VEGF was incorporated into a biodegradable collagen hydrogel for its controlled release. Following implantation of the collagen hydrogel incorporating 0 or 2 microg of VEGF and injection of 0 or 2 microg of VEGF in the solution form into the back subcutis of mice, the hair follicle growth was evaluated photometrically and histologically in terms of the skin color of reverse side of the implanted or injected site, the skin thickness, and the area occupied by hair follicle tissue. Ten days later, the skin color of mice implanted with the collagen hydrogel incorporating 2 microg of VEGF was significantly darker than that injected with 2 pg of VEGF. The collagen hydrogel incorporating VEGF increased the hair follicle area at the implanted site to a significantly greater extent than other agents while significant angiogenetic effect in the skin tissue was observed. VEGF-free, empty collagen hydrogels did not affect the skin darkness, hair follicle growth, and the angiogenesis. Moreover, the hair shaft length was significantly elongated by the collagen hydrogel incorporating VEGF, in marked contrast to other agents. Immunohistolchemicalstaining with proliferating cell nuclear antigen revealed that the collagen hydrogel incorporating VEGF promoted the proliferation of cells around the hair follicle more frequently than free VEGF. We concluded that the controlled release of VEGF more positively acted on the hair growth cycle of mice for hair growth than the injection of free VEGF.

  5. Controlled crack growth specimen for brittle systems

    NASA Technical Reports Server (NTRS)

    Calomino, Anthony M.; Brewer, David N.

    1990-01-01

    A pure Mode 1 fracture specimen and test procedure has been developed which provides extended, stable, through-thickness crack growth in ceramics and other brittle, nonmetallic materials. Fixed displacement loading, applied at the crack mouth, promotes stable crack extension by reducing the stored elastic strain energy. Extremely fine control of applied displacements is achieved by utilizing the Poisson's expansion of a compressively loaded cylindrical pin. Stable cracks were successfully grown in soda-lime glass and monolithic Al2O3 for lengths in excess of 20 mm without uncontrollable catastrophic failure.

  6. Controlled crack growth specimen for brittle systems

    NASA Technical Reports Server (NTRS)

    Calomino, Anthony M.; Brewer, David N.

    1992-01-01

    A pure Mode 1 fracture specimen and test procedure has been developed which provides extended, stable, through-thickness crack growth in ceramics and other brittle, nonmetallic materials. Fixed displacement loading, applied at the crack mouth, promotes stable crack extension by reducing the stored elastic strain energy. Extremely fine control of applied displacements is achieved by utilizing the Poisson's expansion of a compressively loaded cylindrical pin. Stable cracks were successfully grown in soda-lime glass and monolithic Al2O3 for lengths in excess of 2O mm without uncontrollable catastrophic failure.

  7. Controlled crack growth specimen for brittle systems

    NASA Technical Reports Server (NTRS)

    Calomino, Anthony M.; Brewer, David N.

    1992-01-01

    A pure Mode 1 fracture specimen and test procedure has been developed which provides extended, stable, through-thickness crack growth in ceramics and other brittle, nonmetallic materials. Fixed displacement loading, applied at the crack mouth, promotes stable crack extension by reducing the stored elastic strain energy. Extremely fine control of applied displacements is achieved by utilizing the Poisson's expansion of a compressively loaded cylindrical pin. Stable cracks were successfully grown in soda-lime glass and monolithic Al2O3 for lengths in excess of 2O mm without uncontrollable catastrophic failure.

  8. ALK5-mediated transforming growth factor β signaling in neural crest cells controls craniofacial muscle development via tissue-tissue interactions.

    PubMed

    Han, Arum; Zhao, Hu; Li, Jingyuan; Pelikan, Richard; Chai, Yang

    2014-08-01

    The development of the craniofacial muscles requires reciprocal interactions with surrounding craniofacial tissues that originate from cranial neural crest cells (CNCCs). However, the molecular mechanism involved in the tissue-tissue interactions between CNCCs and muscle progenitors during craniofacial muscle development is largely unknown. In the current study, we address how CNCCs regulate the development of the tongue and other craniofacial muscles using Wnt1-Cre; Alk5(fl/fl) mice, in which loss of Alk5 in CNCCs results in severely disrupted muscle formation. We found that Bmp4 is responsible for reduced proliferation of the myogenic progenitor cells in Wnt1-Cre; Alk5(fl/fl) mice during early myogenesis. In addition, Fgf4 and Fgf6 ligands were reduced in Wnt1-Cre; Alk5(fl/fl) mice and are critical for differentiation of the myogenic cells. Addition of Bmp4 or Fgf ligands rescues the proliferation and differentiation defects in the craniofacial muscles of Alk5 mutant mice in vitro. Taken together, our results indicate that CNCCs play critical roles in controlling craniofacial myogenic proliferation and differentiation through tissue-tissue interactions. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  9. ALK5-Mediated Transforming Growth Factor β Signaling in Neural Crest Cells Controls Craniofacial Muscle Development via Tissue-Tissue Interactions

    PubMed Central

    Han, Arum; Zhao, Hu; Li, Jingyuan; Pelikan, Richard

    2014-01-01

    The development of the craniofacial muscles requires reciprocal interactions with surrounding craniofacial tissues that originate from cranial neural crest cells (CNCCs). However, the molecular mechanism involved in the tissue-tissue interactions between CNCCs and muscle progenitors during craniofacial muscle development is largely unknown. In the current study, we address how CNCCs regulate the development of the tongue and other craniofacial muscles using Wnt1-Cre; Alk5fl/fl mice, in which loss of Alk5 in CNCCs results in severely disrupted muscle formation. We found that Bmp4 is responsible for reduced proliferation of the myogenic progenitor cells in Wnt1-Cre; Alk5fl/fl mice during early myogenesis. In addition, Fgf4 and Fgf6 ligands were reduced in Wnt1-Cre; Alk5fl/fl mice and are critical for differentiation of the myogenic cells. Addition of Bmp4 or Fgf ligands rescues the proliferation and differentiation defects in the craniofacial muscles of Alk5 mutant mice in vitro. Taken together, our results indicate that CNCCs play critical roles in controlling craniofacial myogenic proliferation and differentiation through tissue-tissue interactions. PMID:24912677

  10. Triiodothyronine regulates cell growth and survival in renal cell cancer.

    PubMed

    Czarnecka, Anna M; Matak, Damian; Szymanski, Lukasz; Czarnecka, Karolina H; Lewicki, Slawomir; Zdanowski, Robert; Brzezianska-Lasota, Ewa; Szczylik, Cezary

    2016-10-01

    Triiodothyronine plays an important role in the regulation of kidney cell growth, differentiation and metabolism. Patients with renal cell cancer who develop hypothyreosis during tyrosine kinase inhibitor (TKI) treatment have statistically longer survival. In this study, we developed cell based model of triiodothyronine (T3) analysis in RCC and we show the different effects of T3 on renal cell cancer (RCC) cell growth response and expression of the thyroid hormone receptor in human renal cell cancer cell lines from primary and metastatic tumors along with human kidney cancer stem cells. Wild-type thyroid hormone receptor is ubiquitously expressed in human renal cancer cell lines, but normalized against healthy renal proximal tube cell expression its level is upregulated in Caki-2, RCC6, SKRC-42, SKRC-45 cell lines. On the contrary the mRNA level in the 769-P, ACHN, HKCSC, and HEK293 cells is significantly decreased. The TRβ protein was abundant in the cytoplasm of the 786-O, Caki-2, RCC6, and SKRC-45 cells and in the nucleus of SKRC-42, ACHN, 769-P and cancer stem cells. T3 has promoting effect on the cell proliferation of HKCSC, Caki-2, ASE, ACHN, SK-RC-42, SMKT-R2, Caki-1, 786-0, and SK-RC-45 cells. Tyrosine kinase inhibitor, sunitinib, directly inhibits proliferation of RCC cells, while thyroid hormone receptor antagonist 1-850 (CAS 251310‑57-3) has less significant inhibitory impact. T3 stimulation does not abrogate inhibitory effect of sunitinib. Renal cancer tumor cells hypostimulated with T3 may be more responsive to tyrosine kinase inhibition. Moreover, some tumors may be considered as T3-independent and present aggressive phenotype with thyroid hormone receptor activated independently from the ligand. On the contrary proliferation induced by deregulated VHL and or c-Met pathways may transgress normal T3 mediated regulation of the cell cycle.

  11. Hnf1α (MODY3) Controls Tissue-Specific Transcriptional Programs and Exerts Opposed Effects on Cell Growth in Pancreatic Islets and Liver▿ †

    PubMed Central

    Servitja, Joan-Marc; Pignatelli, Miguel; Maestro, Miguel Ángel; Cardalda, Carina; Boj, Sylvia F.; Lozano, Juanjo; Blanco, Enrique; Lafuente, Amàlia; McCarthy, Mark I.; Sumoy, Lauro; Guigó, Roderic; Ferrer, Jorge

    2009-01-01

    Heterozygous HNF1A mutations cause pancreatic-islet β-cell dysfunction and monogenic diabetes (MODY3). Hnf1α is known to regulate numerous hepatic genes, yet knowledge of its function in pancreatic islets is more limited. We now show that Hnf1a deficiency in mice leads to highly tissue-specific changes in the expression of genes involved in key functions of both islets and liver. To gain insights into the mechanisms of tissue-specific Hnf1α regulation, we integrated expression studies of Hnf1a-deficient mice with identification of direct Hnf1α targets. We demonstrate that Hnf1α can bind in a tissue-selective manner to genes that are expressed only in liver or islets. We also show that Hnf1α is essential only for the transcription of a minor fraction of its direct-target genes. Even among genes that were expressed in both liver and islets, the subset of targets showing functional dependence on Hnf1α was highly tissue specific. This was partly explained by the compensatory occupancy by the paralog Hnf1β at selected genes in Hnf1a-deficient liver. In keeping with these findings, the biological consequences of Hnf1a deficiency were markedly different in islets and liver. Notably, Hnf1a deficiency led to impaired large-T-antigen-induced growth and oncogenesis in β cells yet enhanced proliferation in hepatocytes. Collectively, these findings show that Hnf1α governs broad, highly tissue-specific genetic programs in pancreatic islets and liver and reveal key consequences of Hnf1a deficiency relevant to the pathophysiology of monogenic diabetes. PMID:19289501

  12. Artificial intelligence techniques for the control of cancer cells.

    PubMed

    Nicolini, C; Gaglio, S; Ruggiero, C

    1989-04-01

    NEWCHEM, an artificial intelligence system for the control of cancer cell growth, is described. This system takes into account the most recent advances in molecular and cellular biology and in cell-drug interaction, and aims to develop optimal strategies for the selective control of cancer cell through qualitative reasoning from first principles at cellular level.

  13. End stage renal disease serum contains a specific renal cell growth factor

    SciTech Connect

    Klotz, L.H.; Kulkarni, C.; Mills, G. )

    1991-01-01

    End stage renal disease (ESRD) kidneys display abnormal growth characterized by a continuum of cystic disease, adenoma and carcinoma. This study evaluates the hypothesis that serum of patients with ESRD contains increased amounts of a growth factor which specifically induces proliferation of renal cells. ESRD sera compared to sera from normal controls induced a two to three-fold increase in the proliferative rate of renal cell carcinoma cell lines and normal kidney explants compared to cell lines from other sites. The increased proliferative activity of ESRD sera on renal cells was paralleled by an increase in cytosolic free calcium. The growth factor activity was encoded by a polypeptide of between 15 and 30 kd. The activity of ESRD sera on renal cells was not mimicked or inhibited by epidermal growth factor, basic fibroblast growth factor and platelet derived growth factor indicating that the renal cell specific growth factor activity in ESRD is different from these factors.

  14. Growth requirements of human mammary epithelial cells in culture.

    PubMed

    Taylor-Papadimitriou, J; Shearer, M; Stoker, M G

    1977-12-15

    Colony-forming epithelial cells can be separated from the non-dividing "foam cells" in human milk by differential adhesion to glass and freezing. The growth of such partially purified mammary epithelial cells is stimulated by co-culture with non-dividing feeder cells. Foam cells, mitomycin-treated mouse fibroblast lines and human mammary fibroblasts and calf lens epithelial cells are all effective in promoting mammary epithelial cell growth. Contact between epithelial cells and feeders is not required for the growth-promoting effect. The mitogenic effect of epidermal growth factor on mammary epithelial cells also requires feeder cell activity.

  15. 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] controls growth plate development by inhibiting apoptosis in the reserve zone and stimulating response to 1alpha,25(OH)2D3 in hypertrophic cells.

    PubMed

    Boyan, B D; Hurst-Kennedy, J; Denison, T A; Schwartz, Z

    2010-07-01

    Previously we showed that costochondral growth plate resting zone (RC) chondrocytes response primarily to 24R,25(OH)2D3 whereas prehypertrophic and hypertrophic (GC) cells respond to 1alpha,25(OH)2D3. 24R,25(OH)2D3 increases RC cell proliferation and inhibits activity of matrix processing enzymes, suggesting it stabilizes cells in the reserve zone, possibly by inhibiting the matrix degradation characteristic of apoptotic hypertrophic GC cells. To test this, apoptosis was induced in rat RC cells by treatment with exogenous inorganic phosphate (Pi). 24R,25(OH)2D3 blocked apoptotic effects in a dose-dependent manner. Similarly, apoptosis was induced in ATDC5 cell cultures and 24R,25(OH)2D3 blocked this effect. Further studies indicated that 24R,25(OH)2D3 acts via at least two independent pathways. 24R,25(OH)2D3 increases LPA receptor-1 (LPA R1) expression and production of lysophosphatidic acid (LPA), and subsequent LPA R1/3-dependent signaling, thereby decreasing p53 abundance. LPA also increases the Bcl-2/Bax ratio. In addition, 24R,25(OH)2D3 acts by increasing PKC activity. 24R,25(OH)2D3 stimulates 1-hydroxylase activity, resulting in increased levels of 1,25(OH)2D3, and it increases levels of phospholipase A2 activating protein, which is required for rapid 1alpha,25(OH)2D3-dependent activation of PKC in GC cells. These results suggest that 24R,25(OH)2D3 modulates growth plate development by controlling the rate and extent of RC chondrocyte transition to a GC chondrocyte phenotype.

  16. Differential effects of hepatocyte growth factor and keratinocyte growth factor on corneal epithelial cell cycle protein expression, cell survival, and growth

    PubMed Central

    Chandrasekher, Gudiseva; Pothula, Swetha; Bazan, Haydee.E.P.

    2014-01-01

    Purpose Hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF) are secreted in the cornea in response to injury. In this study, we investigated the HGF- and KGF-mediated effect on the expression of cell cycle and apoptosis controlling proteins, cell survival, and growth in the corneal epithelium to better understand the possible role of their signaling mechanisms in repairing epithelial injuries. Methods The cell survival capability of HGF and KGF in epithelial primary cultures was evaluated by using a staurosporine-induced apoptosis model. Apoptosis was quantified with image analysis following nuclear staining with Hoechst fluorescent dye and DNA laddering. Western immunoblotting was used to study the effect of growth factors on the expression of cell cycle- and apoptosis-regulating proteins. Results HGF and KGF protected cells from apoptosis for a short duration (10 h), but only KGF exhibited cell survival capability and maintained cell growth for a longer period (24 h). The onset of apoptosis was accompanied by a significant increase in cell cycle inhibitor p27kip. HGF and KGF suppressed p27kip levels in the apoptosis environment; however, KGF- but not HGF-dependent downregulation in p27kip expression was sustained for a longer duration. Inhibition of phosphatidylinositol 3-kinase/Akt activation blocked HGF- and KGF-mediated control of p27kip expression. Further, when compared to HGF, the presence of KGF produced significant downregulation of p53 and poly(adenosine diphosphate-ribose) polymerase, the key proteins involved in apoptosis and blocked the degradation of G1/S cell cycle progression checkpoint protein retinoblastoma. HGF and KGF upregulated the levels of p21cip, cyclins A, D, and E and cyclin-dependent kinases (CDK2 and CDK4) as well, but the KGF-mediated effect on the expression of these molecules lasted longer. Conclusions Sustained effect of KGF on cell survival and proliferation could be attributed to its ability to inhibit p53

  17. Differential effects of hepatocyte growth factor and keratinocyte growth factor on corneal epithelial cell cycle protein expression, cell survival, and growth.

    PubMed

    Chandrasekher, Gudiseva; Pothula, Swetha; Maharaj, Glenn; Bazan, Haydee E P

    2014-01-01

    Hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF) are secreted in the cornea in response to injury. In this study, we investigated the HGF- and KGF-mediated effect on the expression of cell cycle and apoptosis controlling proteins, cell survival, and growth in the corneal epithelium to better understand the possible role of their signaling mechanisms in repairing epithelial injuries. The cell survival capability of HGF and KGF in epithelial primary cultures was evaluated by using a staurosporine-induced apoptosis model. Apoptosis was quantified with image analysis following nuclear staining with Hoechst fluorescent dye and DNA laddering. Western immunoblotting was used to study the effect of growth factors on the expression of cell cycle- and apoptosis-regulating proteins. HGF and KGF protected cells from apoptosis for a short duration (10 h), but only KGF exhibited cell survival capability and maintained cell growth for a longer period (24 h). The onset of apoptosis was accompanied by a significant increase in cell cycle inhibitor p27(kip). HGF and KGF suppressed p27(kip) levels in the apoptosis environment; however, KGF- but not HGF-dependent downregulation in p27(kip) expression was sustained for a longer duration. Inhibition of phosphatidylinositol 3-kinase/Akt activation blocked HGF- and KGF-mediated control of p27(kip) expression. Further, when compared to HGF, the presence of KGF produced significant downregulation of p53 and poly(adenosine diphosphate-ribose) polymerase, the key proteins involved in apoptosis and blocked the degradation of G1/S cell cycle progression checkpoint protein retinoblastoma. HGF and KGF upregulated the levels of p21(cip), cyclins A, D, and E and cyclin-dependent kinases (CDK2 and CDK4) as well, but the KGF-mediated effect on the expression of these molecules lasted longer. Sustained effect of KGF on cell survival and proliferation could be attributed to its ability to inhibit p53, retinoblastoma, caspases, and p

  18. Nerve growth factor promotes in vitro proliferation of neural stem cells from tree shrews.

    PubMed

    Xiong, Liu-Lin; Chen, Zhi-Wei; Wang, Ting-Hua

    2016-04-01

    Neural stem cells promote neuronal regeneration and repair of brain tissue after injury, but have limited resources and proliferative ability in vivo. We hypothesized that nerve growth factor would promote in vitro proliferation of neural stem cells derived from the tree shrews, a primate-like mammal that has been proposed as an alternative to primates in biomedical translational research. We cultured neural stem cells from the hippocampus of tree shrews at embryonic day 38, and added nerve growth factor (100 μg/L) to the culture medium. Neural stem cells from the hippocampus of tree shrews cultured without nerve growth factor were used as controls. After 3 days, fluorescence microscopy after DAPI and nestin staining revealed that the number of neurospheres and DAPI/nestin-positive cells was markedly greater in the nerve growth factor-treated cells than in control cells. These findings demonstrate that nerve growth factor promotes the proliferation of neural stem cells derived from tree shrews.

  19. Crystal structures of CaSiO3 polymorphs control growth and osteogenic differentiation of human mesenchymal stem cells on bioceramic surfaces.

    PubMed

    Zhang, Nianli; Molenda, James A; Mankoci, Steven; Zhou, Xianfeng; Murphy, William L; Sahai, Nita

    2013-10-01

    The repair and replacement of damaged or diseased human bone tissue requires a stable interface between the orthopedic implant and living tissue. The ideal material should be both osteoconductive (promote bonding to bone) and osteoinductive (induce osteogenic differentiation of cells and generate new bone). Partially resorbable bioceramic materials with both properties are developed by expensive trial-and-error methods. Structure-reactivity relationships for predicting the osteoinductive properties of ceramics would significantly increase the efficiency of developing materials for bone tissue engineering. Here we propose the novel hypothesis that the crystal structure of a bioceramic controls the release rates, subsequent surface modifications due to precipitation of new phases, and thus, the concentrations of soluble factors, and ultimately, the attachment, viability and osteogenic differentiation of human Mesenchymal Stem Cells (hMSCs). To illustrate our hypothesis, we used two CaSiO3 polymorphs, pseudo-wollastonite (psw, β-CaSiO3) and wollastonite (wol, α-CaSiO3) as scaffolds for hMSC culture. Polymorphs are materials which have identical chemical composition and stoichiometry, but different crystal structures. We combined the results of detailed surface characterizations, including environmental Scanning Electron Microscopy (SEM) back-scattered imaging, and spot-analysis and 2D elemental mapping by SEM-Energy Dispersive X-ray (SEM-EDX), High Resolution Transmission Electron Microscopy (HRTEM) and surface roughness analysis; culture medium solution analyses; and molecular/genetic assays from cell culture. Our results confirmed the hypothesis that the psw polymorph, which has a strained silicate ring structure, is more osteoinductive than the wol polymorph, which has a more stable, open silicate chain structure. The observations could be attributed to easier dissolution (resorption) of psw compared to wol, which resulted in concentration profiles that were more

  20. A novel role for the 3′-5′ exoribonuclease Dis3L2 in controlling cell proliferation and tissue growth

    PubMed Central

    2016-01-01

    ABSTRACT In a complex organism, cell proliferation and apoptosis need to be precisely controlled in order for tissues to develop correctly. Excessive cell proliferation can lead to diseases such as cancer. We have shown that the exoribonuclease Dis3L2 is required for the correct regulation of proliferation in a natural tissue within the model organism Drosophila melanogaster. Dis3L2 is a member of a highly conserved family of exoribonucleases that degrade RNA in a 3′-5′ direction. We show that knockdown of dis3L2 in the Drosophila wing imaginal discs results in substantial wing overgrowth due to increased cellular proliferation rather than an increase in cell size. Imaginal discs are specified in the embryo before proliferating and differentiating to form the adult structures of the fly. Using RNA-seq we identified a small set of mRNAs that are sensitive to Dis3L2 activity. Of the mRNAs which increase in levels and are therefore potential targets of Dis3L2, we identified 2 that change at the post-transcriptional level but not at the transcriptional level, namely CG2678 (a transcription factor) and pyrexia (a TRP cation channel). We also demonstrate a compensatory effect between Dis3L2 and the 5′-3′ exoribonuclease Pacman demonstrating that these 2 exoribonucleases function to regulate opposing pathways within the developing tissue. This work provides the first description of the molecular and developmental consequences of Dis3L2 inactivation in a non-human animal model. The work is directly relevant to the understanding of human overgrowth syndromes such as Perlman syndrome. PMID:27630034

  1. Crystal structures of CaSiO3 polymorphs control growth and osteogenic differentiation of human mesenchymal stem cells on bioceramic surfaces†

    PubMed Central

    Zhang, Nianli; Molenda, James A.; Mankoci, Steven; Zhou, Xianfeng; Murphy, William L.

    2014-01-01

    The repair and replacement of damaged or diseased human bone tissue requires a stable interface between the orthopedic implant and living tissue. The ideal material should be both osteoconductive (promote bonding to bone) and osteoinductive (induce osteogenic differentiation of cells and generate new bone). Partially resorbable bioceramic materials with both properties are developed by expensive trial-and-error methods. Structure–reactivity relationships for predicting the osteoinductive properties of ceramics would significantly increase the efficiency of developing materials for bone tissue engineering. Here we propose the novel hypothesis that the crystal structure of a bioceramic controls the release rates, subsequent surface modifications due to precipitation of new phases, and thus, the concentrations of soluble factors, and ultimately, the attachment, viability and osteogenic differentiation of human Mesenchymal Stem Cells (hMSCs). To illustrate our hypothesis, we used two CaSiO3 polymorphs, pseudo-wollastonite (psw, β-CaSiO3) and wollastonite (wol, α-CaSiO3) as scaffolds for hMSC culture. Polymorphs are materials which have identical chemical composition and stoichiometry, but different crystal structures. We combined the results of detailed surface characterizations, including environmental Scanning Electron Microscopy (SEM) back-scattered imaging, and spot-analysis and 2D elemental mapping by SEM-Energy Dispersive X-ray (SEM-EDX), High Resolution Transmission Electron Microscopy (HRTEM) and surface roughness analysis; culture medium solution analyses; and molecular/genetic assays from cell culture. Our results confirmed the hypothesis that the psw polymorph, which has a strained silicate ring structure, is more osteoinductive than the wol polymorph, which has a more stable, open silicate chain structure. The observations could be attributed to easier dissolution (resorption) of psw compared to wol, which resulted in concentration profiles that were

  2. Cell growth and migration under octenidine-antiseptic treatment.

    PubMed

    Jenull, S; Hojdar, K; Laggner, H; Velimirov, B; Zemann, N; Huettinger, M

    2015-06-01

    The toxicity of octenidine antiseptics in cultured cells contrasts their good tolerability in tissue. This phenomenon prompted us to examine which cell culture conditions allow survival and proliferation and to investigate a possible modulation of toxicity by the extracellular matrix proteoglycan chondroitin sulfate. We tested fibroblasts and MCF7 cells for growth using the MTT test, and assessed wound healing potency with a laceration assay. Expression levels of the genes involved in controlling wound healing were assessed with RT-PCR. A 24 hour exposure to the octenidine-based solution was found incompatible with cell growth. When octenidine solution (0.5-0.5mg/l) was coated on dishes, growth was profoundly reduced after 24 hours, however there was no cytotoxic effect at 0.012 mg/l. Interestingly, when dishes were first coated with chondroitin sulfate the cytotoxicity of octenidine-based solution was modulated. Cell migration was not inhibited by octenidine-based solution treatment (2 minutes; 15 mg/l). No significant changes in gene expression levels in response to the octenidine-based solution treatment were detected. In cell culture conditions application of the octenidine-based solution without toxicity can be observed, comparable to the minimal application required to give full bactericidal effect. Alteration of toxicity by interaction with chondroitin sulfate in cell culture suggests a similar function for extraceullar matrix in intact tissue.

  3. Translational control in germline stem cell development

    PubMed Central

    Slaidina, Maija

    2014-01-01

    Stem cells give rise to tissues and organs during development and maintain their integrity during adulthood. They have the potential to self-renew or differentiate at each division. To ensure proper organ growth and homeostasis, self-renewal versus differentiation decisions need to be tightly controlled. Systematic genetic studies in Drosophila melanogaster are revealing extensive regulatory networks that control the switch between stem cell self-renewal and differentiation in the germline. These networks, which are based primarily on mutual translational repression, act via interlocked feedback loops to provide robustness to this important fate decision. PMID:25313405

  4. Budding yeast colony growth study based on circular granular cell

    NASA Astrophysics Data System (ADS)

    Aprianti, Devi; Khotimah, S. N.; Viridi, S.

    2016-08-01

    Yeast colony growth can be modelled by using circular granular cells, which can grow and produce buds. The bud growth angle can be set to regulate cell budding pattern. Cohesion force, contact force and Stokes force were adopted to accommodate the behaviour and interactions among cells. Simulation steps are divided into two steps, the explicit step is due to cell growing and implicit step for the cell rearrangement. Only in explicit step that time change was performed. In this study, we examine the influence of cell diameter growth time and reproduction time combination toward the growth of cell number and colony formation. We find a commutative relation between the cell diameter growth time and reproduction time to the specific growth rate. The greater value of the multiplication of the parameters, the smaller specific growth rate is obtained. It also shows a linear correlation between the specific growth rate and colony diameter growth rate.

  5. Fibroblast cell interactions with human melanoma cells affect tumor cell growth as a function of tumor progression.

    PubMed Central

    Cornil, I; Theodorescu, D; Man, S; Herlyn, M; Jambrosic, J; Kerbel, R S

    1991-01-01

    It is known from a variety of experimental systems that the ability of tumor cells to grow locally and metastasize can be affected by the presence of adjacent normal tissues and cells, particularly mesenchymally derived stromal cells such as fibroblasts. However, the comparative influence of such normal cell-tumor cell interactions on tumor behavior has not been thoroughly investigated from the perspective of different stages of tumor progression. To address this question we assessed the influence of normal dermal fibroblasts on the growth of human melanoma cells obtained from different stages of tumor progression. We found that the in vitro growth of most (4 out of 5) melanoma cell lines derived from early-stage radial growth phase or vertical growth phase metastatically incompetent primary lesions is repressed by coculture with normal dermal fibroblasts, suggesting that negative homeostatic growth controls are still operative on melanoma cells from early stages of disease. On the other hand, 9 out of 11 melanoma cell lines derived from advanced metastatically competent vertical growth phase primary lesions, or from distant metastases, were found to be consistently stimulated to grow in the presence of dermal fibroblasts. Evidence was obtained to show that this discriminatory fibroblastic influence is mediated by soluble inhibitory and stimulatory growth factor(s). Taken together, these results indicate that fibroblast-derived signals can have antithetical growth effects on metastatic versus metastatically incompetent tumor subpopulations. This resultant conversion in responsiveness to host tissue environmental factors may confer upon small numbers of metastatically competent cells a growth advantage, allowing them to escape local growth constraints both in the primary tumor site and at distant ectopic tissue sites. PMID:2068080

  6. Craniopharyngioma cell growth is promoted by growth hormone (GH) and is inhibited by tamoxifen: involvement of growth hormone receptor (GHR) and IGF-1 receptor (IGF-1R).

    PubMed

    Li, Qiang; You, Chao; Liu, Liang; Rao, Zhengxi; Sima, Xiutian; Zhou, Liangxue; Xu, Jianguo

    2013-01-01

    Hormone receptors are related to the biological behavior and recurrence of craniopharyngioma (CP). The effect of therapeutic growth hormone (GH) replacement on CP growth remains largely unclear. We intended to study expression patterns of GH-related receptors in CP, and to study the effect of GH and its mediator, insulin-like growth factor-1 (IGF-1), as well as tamoxifen, on primary CP cell cultures. Primary cell cultures were established from fresh tumor specimens. The expression of GH receptor (GHR) and IGF-1 receptor (IGF-1R) in tumor specimens was studied using immunohistochemistry. Cell cultures were treated with various concentrations of recombinant GH, IGF-1 and tamoxifen. Cell growth promotion or inhibition was assayed using the Trypan blue dye exclusion test of cell viability. Expression of GHR, IGF-1R, phosphorylated-Akt and Akt after treatment was studied using Western blot assay. Twenty-nine primary cultures from 36 patients were established. GHR and IGF-1R were expressed in tumor tissue. The promotion of cell growth by GH compared to control was most prominent at 100 ng/mL, while inhibition by tamoxifen was concentration dependent. IGF-1 was more effective in promoting growth in CP cell cultures with high IGF-1R expression, and it increased phosphorylation of Akt protein. Primary cell cultures can be established in more than 80% of fresh CP specimens. GH and its endogenous mediator, IGF-1, promotes CP cell growth in vitro, while tamoxifen inhibits growth. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Growth behavior of cochlear nucleus neuronal cells on semiconductor substrates.

    PubMed

    Rak, Kristen; Wasielewski, Natalia; Radeloff, Andreas; Scherzed, Agmal; Jablonka, Sibylle; Hagen, Rudolf; Mlynski, Robert

    2011-05-01

    Auditory brainstem implants provide sound information by direct stimulation of the cochlear nucleus to patients with dysfunctional or absent cranial nerve VIII. In contrast to patients with cochlear implants, the use of the auditory brainstem implants is less successful. This cannot be fully explained by the difference location of stimulation but a rather unspecific neuronal stimulation. The aim of this study was to further examine neuronal cells of the cochlear nucleus and to test their interactions with semiconductor substrates as a potential electrode material for improved auditory brainstem implants. The cochlear nuclei of postnatal day 7 rats were microsurgically dissected. The tissue was dissociated enzymatically and plated on coverslips as control and on the semiconductor substrates silicon or silicon nitride. After 4 days in culture the morphology and growth of dissociated cells was determined by fluorescence and scanning electron microscopy. Dissociated cells of the cochlear nucleus showed reduced cell growth on semiconductor substrates compared with controls. SEM analysis demonstrated close contact of neurons with supporting cells in culture and good adherence of neuronal growth cones on the used materials. These findings present basic knowledge for the development of neuron-electrode interfaces for future auditory brainstem implants. Copyright © 2011 Wiley Periodicals, Inc.

  8. Metabolism, cell growth and the bacterial cell cycle

    PubMed Central

    Wang, Jue D.; Levin, Petra A.

    2010-01-01

    Adaptation to fluctuations in nutrient availability is a fact of life for single-celled organisms in the ‘wild’. A decade ago our understanding of how bacteria adjust cell cycle parameters to accommodate changes in nutrient availability stemmed almost entirely from elegant physiological studies completed in the 1960s. In this Opinion article we summarize recent groundbreaking work in this area and discuss potential mechanisms by which nutrient availability and metabolic status are coordinated with cell growth, chromosome replication and cell division. PMID:19806155

  9. Cardiac hypertrophy: signal transduction, transcriptional adaptation, and altered growth control.

    PubMed

    Wagner, M; Mascareno, E; Siddiqui, M A

    1999-06-30

    Cardiac hypertrophy results from the enlargement of cardiac muscle and fibroblast cells. This abnormal pattern of growth can be elicited by a number of hypertrophic agents, such as cytokines and hormones that participate in normal cell-cell signaling events during development. Under conditions yet to be defined, these same signaling molecules can cause hypertrophy of the heart. Intracellular signal transduction pathways appear to be the prime means by which the hypertrophic signal is transduced in cardiomyocytes. There is no evidence that the signal transduction pathways in hypertrophic cardiomyocytes differ from those of normal cardiomyocytes. Perhaps the signal itself is aberrant, mistimed, misplaced, or occurring at non-physiological concentrations. Alternatively, as a quiescent cell, the cardiomyocyte may not be able to respond completely to a growth signal by turning on its proliferative machinery. Three avenues of research are described: (1) the study of the upregulation of the cardiac MLC-2 gene, (2) STAT proteins and activation of angiotensin II, and (3) hypertrophy as a perturbation of cell cycle controls.

  10. Intracellular growth of Mycobacterium tuberculosis after macrophage cell death leads to serial killing of host cells.

    PubMed

    Mahamed, Deeqa; Boulle, Mikael; Ganga, Yashica; Mc Arthur, Chanelle; Skroch, Steven; Oom, Lance; Catinas, Oana; Pillay, Kelly; Naicker, Myshnee; Rampersad, Sanisha; Mathonsi, Colisile; Hunter, Jessica; Wong, Emily B; Suleman, Moosa; Sreejit, Gopalkrishna; Pym, Alexander S; Lustig, Gila; Sigal, Alex

    2017-01-28

    A hallmark of pulmonary tuberculosis is the formation of macrophage-rich granulomas. These may restrict Mycobacterium tuberculosis (Mtb) growth, or progress to central necrosis and cavitation, facilitating pathogen growth. To determine factors leading to Mtb proliferation and host cell death, we used live cell imaging to track Mtb infection outcomes in individual primary human macrophages. Internalization of Mtb aggregates caused macrophage death, and phagocytosis of large aggregates was more cytotoxic than multiple small aggregates containing similar numbers of bacilli. Macrophage death did not result in clearance of Mtb. Rather, it led to accelerated intracellular Mtb growth regardless of prior activation or macrophage type. In contrast, bacillary replication was controlled in live phagocytes. Mtb grew as a clump in dead cells, and macrophages which internalized dead infected cells were very likely to die themselves, leading to a cell death cascade. This demonstrates how pathogen virulence can be achieved through numbers and aggregation states.

  11. Cell size and growth regulation in the Arabidopsis thaliana apical stem cell niche

    PubMed Central

    Willis, Lisa; Refahi, Yassin; Wightman, Raymond; Landrein, Benoit; Teles, José; Huang, Kerwyn Casey; Meyerowitz, Elliot M.

    2016-01-01

    Cell size and growth kinetics are fundamental cellular properties with important physiological implications. Classical studies on yeast, and recently on bacteria, have identified rules for cell size regulation in single cells, but in the more complex environment of multicellular tissues, data have been lacking. In this study, to characterize cell size and growth regulation in a multicellular context, we developed a 4D imaging pipeline and applied it to track and quantify epidermal cells over 3–4 d in Arabidopsis thaliana shoot apical meristems. We found that a cell size checkpoint is not the trigger for G2/M or cytokinesis, refuting the unexamined assumption that meristematic cells trigger cell cycle phases upon reaching a critical size. Our data also rule out models in which cells undergo G2/M at a fixed time after birth, or by adding a critical size increment between G2/M transitions. Rather, cell size regulation was intermediate between the critical size and critical increment paradigms, meaning that cell size fluctuations decay by ∼75% in one generation compared with 100% (critical size) and 50% (critical increment). Notably, this behavior was independent of local cell–cell contact topologies and of position within the tissue. Cells grew exponentially throughout the first >80% of the cell cycle, but following an asymmetrical division, the small daughter grew at a faster exponential rate than the large daughter, an observation that potentially challenges present models of growth regulation. These growth and division behaviors place strong constraints on quantitative mechanistic descriptions of the cell cycle and growth control. PMID:27930326

  12. Controlling Cell Function with Geometry

    NASA Astrophysics Data System (ADS)

    Mrksich, Milan

    2012-02-01

    This presentation will describe the use of patterned substrates to control cell shape with examples that illustrate the ways in which cell shape can regulate cell function. Most cells are adherent and must attach to and spread on a surface in order to survive, proliferate and function. In tissue, this surface is the extracellular matrix (ECM), an insoluble scaffold formed by the assembly of several large proteins---including fibronectin, the laminins and collagens and others---but in the laboratory, the surface is prepared by adsorbing protein to glass slides. To pattern cells, gold-coated slides are patterned with microcontact printing to create geometric features that promote cell attachment and that are surrounded by inert regions. Cells attach to these substrates and spread to adopt the shape defined by the underlying pattern and remain stable in culture for several days. Examples will be described that used a series of shapes to reveal the relationship between the shape of the cell and the structure of its cytoskeleton. These geometric cues were used to control cell polarity and the tension, or contractility, present in the cytoskeleton. These rules were further used to control the shapes of mesenchymal stem cells and in turn to control the differentiation of these cells into specialized cell types. For example, stem cells that were patterned into a ``star'' shape preferentially differentiated into bone cells whereas those that were patterned into a ``flower'' shape preferred a fat cell fate. These influences of shape on differentiation depend on the mechanical properties of the cytoskeleton. These examples, and others, reveal that shape is an important cue that informs cell function and that can be combined with the more common soluble cues to direct and study cell function.

  13. Semiconductor nanowires: Controlled growth and thermal properties

    NASA Astrophysics Data System (ADS)

    Wu, Yiying

    This dissertation presents an experimental study of the controlled growth of semiconductor nanowires and their thermophysical properties. The synthesis of nanowires was based on the well-known Vapor-Liquid-Solid (VLS) mechanism in which the growth of nanowire is initiated by a nanosized liquid droplet. The prepared nanowires are single-crystalline with certain preferred growth direction. Nanowires with different compositions have been synthesized, including Si, Ge, boron and MgB2. The control of nanowire composition, diameter and orientation has also been achieved. In addition, a Pulsed Laser Ablation-Chemical Vapor Deposition (PLA-CVD) hybrid process was developed to synthesize Si/SiGe longitudinally superlattice nanowires. The thermal conductivity of individual pure Si nanowire and Si/SiGe nanowire was measured using a microfabricated suspended device over a temperature range of 20--320 K. The thermal conductivities of individual 22, 37, 56, and 115 nm diameter single crystalline intrinsic Si nanowires were much lower than the bulk value due to the strong phonon boundary scattering. Except for the 22 nm diameter nanowire, theoretical predictions using a modified Callaway model fit the experimental data very well. The data for the 22 nm diameter wire suggest that changes in phonon dispersion due to confinement can cause additional thermal conductivity reduction. The Si/SiGe superlattice nanowires with diameters of 83 run and 58 nm were also measured. Their thermal conductivities are smaller than pure Si nanowire with similar diameter, as well as Si/SiGe superlattice thin film with comparable period. Both the alloying scattering and the boundary scattering are believed to contribute to this reduction. Size dependent melting-recrystallization study of the carbon-sheathed semiconductor Ge nanowires was carried out in in-situ high temperature transmission electron microscope (TEM). Significant depression in melting temperature with decreasing size of the nanowires as

  14. Mitotic phosphorylation of Exo84 disrupts exocyst assembly and arrests cell growth.

    PubMed

    Luo, Guangzuo; Zhang, Jian; Luca, Francis C; Guo, Wei

    2013-07-08

    The rate of eukaryotic cell growth is tightly controlled for proper progression through each cell cycle stage and is important for cell size homeostasis. It was previously shown that cell growth is inhibited during mitosis when cells are preparing for division. However, the mechanism for growth arrest at this stage is unknown. Here we demonstrate that exocytosis of a select group of cargoes was inhibited before the metaphase-anaphase transition in the budding yeast Saccharomyces cerevisiae. The cyclin-dependent kinase, Cdk1, when bound to the mitotic cyclin Clb2, directly phosphorylated Exo84, a component of the exocyst complex essential for exocytosis. Mitotic phosphorylation of Exo84 disrupted the assembly of the exocyst complex, thereby affecting exocytosis and cell surface expansion. Our study demonstrates the coordination between membrane trafficking and cell cycle progression and provides a molecular mechanism by which cell growth is controlled during the cell division cycle.

  15. Targeting the erythropoietin receptor on glioma cells reduces tumour growth

    SciTech Connect

    Peres, Elodie A.; Valable, Samuel; Guillamo, Jean-Sebastien; Marteau, Lena; Bernaudin, Jean-Francois; Roussel, Simon; Lechapt-Zalcman, Emmanuele; Bernaudin, Myriam; Petit, Edwige

    2011-10-01

    Hypoxia has been shown to be one of the major events involved in EPO expression. Accordingly, EPO might be expressed by cerebral neoplastic cells, especially in glioblastoma, known to be highly hypoxic tumours. The expression of EPOR has been described in glioma cells. However, data from the literature remain descriptive and controversial. On the basis of an endogenous source of EPO in the brain, we have focused on a potential role of EPOR in brain tumour growth. In the present study, with complementary approaches to target EPO/EPOR signalling, we demonstrate the presence of a functional EPO/EPOR system on glioma cells leading to the activation of the ERK pathway. This EPO/EPOR system is involved in glioma cell proliferation in vitro. In vivo, we show that the down-regulation of EPOR expression on glioma cells reduces tumour growth and enhances animal survival. Our results support the hypothesis that EPOR signalling in tumour cells is involved in the control of glioma growth.

  16. Inhibitory control of growth hormone secretion by somatostatin in rat pituitary GC cells: sst(2) but not sst(1) receptors are coupled to inhibition of single-cell intracellular free calcium concentrations.

    PubMed

    Cervia, Davide; Petrucci, Cristina; Bluet-Pajot, Marie Thérèse; Epelbaum, Jacques; Bagnoli, Paola

    2002-08-01

    Rat pituitary tumor cells (GC cells) exhibit spontaneous oscillations of intracellular free calcium concentration ([Ca(2+)](i)) that allow continuous release of growth hormone (GH). Of the somatostatin (SRIH) receptor subtypes (sst receptors) mediating SRIH action, sst(1) and sst(2) receptors are highly expressed by GC cell membranes. In the present study, the effects of sst(1) or sst(2) receptor activation on single-cell [Ca(2+)](i) were investigated in GC cells by confocal fluorescence microscopy. In addition, the effects of sst(1) or sst(2) receptor activation on GH secretion were also studied. Our results demonstrate that SRIH decreases [Ca(2+)](i) baseline and almost completely blocks Ca(2+) transients through activation of sst(2) but not of sst(1) receptors. In contrast, SRIH effectively inhibits GH secretion through activation of both sst(1) and sst(2) receptors. Blocking Ca(2+) transients is less efficient than SRIH to inhibit GH release. The cyclic octapeptide, CYN-154806, antagonizes sst(2) receptors at [Ca(2+)](i) since it abolishes the sst(2) receptor-mediated inhibition of [Ca(2+)](i) without affecting single-cell Ca(2+) signals. On the other hand, CYN-154806 alone potently inhibits GH secretion through the involvement of pertussis toxin-sensitive G proteins. In conclusion, the present results demonstrate that SRIH inhibition of GH release in GC cells involves mechanisms either dependent or independent on SRIH modulation of [Ca(2+)](i). The implications of CYN-154806 inhibition of GH secretion are discussed. Copyright 2002 S. Karger AG, Basel

  17. Tissue growth and tumorigenesis in Drosophila: cell polarity and the Hippo pathway.

    PubMed

    Richardson, Helena E; Portela, Marta

    2017-03-28

    Cell polarity regulation is critical for defining membrane domains required for the establishment and maintenance of the apical-basal axis in epithelial cells (apico-basal polarity), asymmetric cell divisions, planar organization of tissues (planar cell polarity), and the formation of the front-rear axis in cell migration (front-rear polarity). In the vinegar fly, Drosophila melanogaster, cell polarity regulators also interact with the Hippo tissue growth control signaling pathway. In this review we survey the recent Drosophila literature linking cell polarity regulators with the Hippo pathway in epithelial tissue growth, neural stem cell asymmetric divisions and in cell migration in physiological and tumorigenic settings.

  18. FNC efficiently inhibits mantle cell lymphoma growth.

    PubMed

    Zhang, Yan; Zhang, Rong; Ding, Xixi; Peng, Bangan; Wang, Ning; Ma, Fang; Peng, Youmei; Wang, Qingduan; Chang, Junbiao

    2017-01-01

    FNC, 2'-deoxy-2'-β-fluoro-4'-azidocytidine, is a novel cytidine analogue, that has shown strong antiproliferative activity in human lymphoma, lung adenocarcinoma and acute myeloid leukemia. In this study, we investigated the effects of FNC on mantle cell lymphoma (MCL) and the underlying mechanisms. In in vitro experiments, cell viability was detected by the CCK8 assay, and cell cycle progression and apoptosis were assessed by flow cytometry, and the expression of relative apoptosis proteins were detected by Western Blot. The in vivo antitumor effect of FNC was investigated in a SCID xenograft model. Finally, the mechanisms of action of FNC were assessed using a whole human genome expression profile chip. The data showed that FNC inhibited cell growth in a dose- and time-dependent manner, and FNC could induce apoptosis by the death recepter pathways in JeKo-1 cells and arrest the cell cycle in the G1/S or G2/M phase. Notably, FNC showed in vivo efficacy in mice bearing JeKo-1 xenograft tumors. Gene expression profile analysis revealed that the differentially expressed genes were mainly focused on the immune system process, cellular process and death. These findings implied that FNC may be a valuable therapeutic in mantle cell lymphoma and provided an experimental basis for the early clinical application of FNC.

  19. FNC efficiently inhibits mantle cell lymphoma growth

    PubMed Central

    Ding, Xixi; Peng, Bangan; Wang, Ning; Ma, Fang; Peng, Youmei; Wang, Qingduan; Chang, Junbiao

    2017-01-01

    FNC, 2'-deoxy-2'-β-fluoro-4'-azidocytidine, is a novel cytidine analogue, that has shown strong antiproliferative activity in human lymphoma, lung adenocarcinoma and acute myeloid leukemia. In this study, we investigated the effects of FNC on mantle cell lymphoma (MCL) and the underlying mechanisms. In in vitro experiments, cell viability was detected by the CCK8 assay, and cell cycle progression and apoptosis were assessed by flow cytometry, and the expression of relative apoptosis proteins were detected by Western Blot. The in vivo antitumor effect of FNC was investigated in a SCID xenograft model. Finally, the mechanisms of action of FNC were assessed using a whole human genome expression profile chip. The data showed that FNC inhibited cell growth in a dose- and time-dependent manner, and FNC could induce apoptosis by the death recepter pathways in JeKo-1 cells and arrest the cell cycle in the G1/S or G2/M phase. Notably, FNC showed in vivo efficacy in mice bearing JeKo-1 xenograft tumors. Gene expression profile analysis revealed that the differentially expressed genes were mainly focused on the immune system process, cellular process and death. These findings implied that FNC may be a valuable therapeutic in mantle cell lymphoma and provided an experimental basis for the early clinical application of FNC. PMID:28333959

  20. The TIP GROWTH DEFECTIVE1 S-acyl transferase regulates plant cell growth in Arabidopsis.

    PubMed

    Hemsley, Piers A; Kemp, Alison C; Grierson, Claire S

    2005-09-01

    TIP GROWTH DEFECTIVE1 (TIP1) of Arabidopsis thaliana affects cell growth throughout the plant and has a particularly strong effect on root hair growth. We have identified TIP1 by map-based cloning and complementation of the mutant phenotype. TIP1 encodes an ankyrin repeat protein with a DHHC Cys-rich domain that is expressed in roots, leaves, inflorescence stems, and floral tissue. Two homologues of TIP1 in yeast (Saccharomyces cerevisiae) and human (Homo sapiens) have been shown to have S-acyl transferase (also known as palmitoyl transferase) activity. S-acylation is a reversible hydrophobic protein modification that offers swift, flexible control of protein hydrophobicity and affects protein association with membranes, signal transduction, and vesicle trafficking within cells. We show that TIP1 binds the acyl group palmitate, that it can rescue the morphological, temperature sensitivity, and yeast casein kinase2 localization defects of the yeast S-acyl transferase mutant akr1Delta, and that inhibition of acylation in wild-type Arabidopsis roots reproduces the Tip1- mutant phenotype. Our results demonstrate that S-acylation is essential for normal plant cell growth and identify a plant S-acyl transferase, an essential research tool if we are to understand how this important, reversible lipid modification operates in plant cells.

  1. Synergistic activation of cells by Epstein-Barr virus and B-cell growth factor.

    PubMed Central

    Hutt-Fletcher, L M

    1987-01-01

    Infection with Epstein-Barr virus (EBV) is initiated by virus binding to the C3dg-C3d receptor CR2. Several workers have implicated this receptor in the control of B-cell activation by examining the effects of antibodies to CR2 and isolated C3d on B-cell proliferation and differentiation. We report here on the activating effects of irradiated EBV, which retains its capacity to bind to CR2 but loses its ability to function as a T-independent B-cell activator. EBV synergized with B-cell growth factor in the induction of uptake of tritiated thymidine by T cell-depleted leukocytes from seronegative donors but did not induce secretion of immunoglobulin. Synergism could be inhibited with an anti-viral antibody that inhibited binding of EBV to CR2. No similar synergism was found between EBV and recombinant interleukin 2, interleukin 1 alpha, or gamma interferon or with the lipid A fraction of bacterial lipopolysaccharide. EBV may thus initiate B-cell activation as it binds to CR2. Infectious virus may, under normal circumstances, induce the cell to make those growth factors necessary to support B-cell proliferation; the difficulty of transforming cells with transfected EBV DNA may in part reflect the absence of an activation event provided by intact virus as it attaches to CR2. The synergism of EBV and B-cell growth factor more clearly distinguishes the effects of B-cell growth factor from those of interleukin 1 and interleukin 2 in other models of B-cell activation. Thus, this may be a useful model for further delineation of unique effects of B-cell growth factor on B-cell function. PMID:3027404

  2. Microtubule guidance tested through controlled cell geometry

    PubMed Central

    Huda, Sabil; Soh, Siowling; Pilans, Didzis; Byrska-Bishop, Marta; Kim, Jiwon; Wilk, Gary; Borisy, Gary G.; Kandere-Grzybowska, Kristiana; Grzybowski, Bartosz A.

    2012-01-01

    Summary In moving cells dynamic microtubules (MTs) target and disassemble substrate adhesion sites (focal adhesions; FAs) in a process that enables the cell to detach from the substrate and propel itself forward. The short-range interactions between FAs and MT plus ends have been observed in several experimental systems, but the spatial overlap of these structures within the cell has precluded analysis of the putative long-range mechanisms by which MTs growing through the cell body reach FAs in the periphery of the cell. In the work described here cell geometry was controlled to remove the spatial overlap of cellular structures thus allowing for unambiguous observation of MT guidance. Specifically, micropatterning of living cells was combined with high-resolution in-cell imaging and gene product depletion by means of RNA interference to study the long-range MT guidance in quantitative detail. Cells were confined on adhesive triangular microislands that determined cell shape and ensured that FAs localized exclusively at the vertices of the triangular cells. It is shown that initial MT nucleation at the centrosome is random in direction, while the alignment of MT trajectories with the targets (i.e. FAs at vertices) increases with an increasing distance from the centrosome, indicating that MT growth is a non-random, guided process. The guided MT growth is dependent on the presence of FAs at the vertices. The depletion of either myosin IIA or myosin IIB results in depletion of F-actin bundles and spatially unguided MT growth. Taken together our findings provide quantitative evidence of a role for long-range MT guidance in MT targeting of FAs. PMID:22992457

  3. MicroRNA-221 promotes human non-small cell lung cancer cell H460 growth.

    PubMed

    Xu, Yiming; Zhong, Chongjun; Ding, Shengguang; Huang, Haitao; Shen, Zhenya

    2015-01-01

    MicroRNA (miRNA-221) has been reported to be a regulator of cell proliferation. Here we intended to investigate the role of miRNA-221 in regulating the growth of human non-small cell lung cancer cell line H460. H460 cells were transfected with miRNA-221 mimics/inhibitors or their respective negative controls. Real-time quantitative PCRs (qRT-PCRs) were used to confirm the effects of miRNA-221 mimics and inhibitors in H460 cells while Cell Counting Kit 8 (CCK-8) and 5-Ethynyl-2'-deoxyuridine (EdU) assay were used to access the cell viability and proliferation. P27 and P57, as putative targets of miRNA-221, were determined by qRT-PCRs in H460 cells. We found that overexpression of miRNA-221 led to increased proliferative rate and cell viability in H460 cells while down-regulation of miRNA-221 decreased those effects. P27 but not P57 was identified as a potential target gene of miRNA-221 in H460 as P27 was negatively regulated by miRNA-221 in the protein level. In conclusion, this study suggests that miRNA-221 controls human non-small cell lung cancer cell H460 growth potentially by targeting P57. Inhibition of miRNA-221 represents a novel potential treatment for human non-small cell lung cancer.

  4. Mast Cells Synthesize, Store, and Release Nerve Growth Factor

    NASA Astrophysics Data System (ADS)

    Leon, A.; Buriani, A.; dal Toso, R.; Fabris, M.; Romanello, S.; Aloe, L.; Levi-Montalcini, R.

    1994-04-01

    Mast cells and nerve growth factor (NGF) have both been reported to be involved in neuroimmune interactions and tissue inflammation. In many peripheral tissues, mast cells interact with the innervating fibers. Changes in the behaviors of both of these elements occur after tissue injury/inflammation. As such conditions are typically associated with rapid mast cell activation and NGF accumulation in inflammatory exudates, we hypothesized that mast cells may be capable of producing NGF. Here we report that (i) NGF mRNA is expressed in adult rat peritoneal mast cells; (ii) anti-NGF antibodies clearly stain vesicular compartments of purified mast cells and mast cells in histological sections of adult rodent mesenchymal tissues; and (iii) medium conditioned by peritoneal mast cells contains biologically active NGF. Mast cells thus represent a newly recognized source of NGF. The known actions of NGF on peripheral nerve fibers and immune cells suggest that mast cell-derived NGF may control adaptive/reactive responses of the nervous and immune systems toward noxious tissue perturbations. Conversely, alterations in normal mast cell behaviors may provoke maladaptive neuroimmune tissue responses whose consequences could have profound implications in inflammatory disease states, including those of an autoimmune nature.

  5. Growth factor control of epidermal growth factor receptor kinase activity via an intramolecular mechanism.

    PubMed

    Koland, J G; Cerione, R A

    1988-02-15

    The mechanism by which the protein kinase activity of the epidermal growth factor (EGF) receptor is activated by binding of growth factor was investigated. Detergent-solubilized receptor in monomeric form was isolated by sucrose density gradient centrifugation and both its kinase and autophosphorylation activities monitored. In a low ionic strength medium and with MnCl2 as an activator, the activity of the monomeric receptor was EGF-independent. However, with 0.25 M ammonium sulfate present, the MnCl2-stimulated kinase activity was strikingly EGF-dependent. In contrast, the kinase activity expressed in the presence of MgCl2 showed growth factor control in the absence of added salt. Under the conditions of these experiments there was apparently little tendency for growth factor to induce aggregation of the receptor, indicating that the allosteric activation of the receptor kinase by EGF occurred via an intramolecular mechanism. Whereas detergent-solubilized receptor was the subject of these studies, the kinase activity of cell surface receptors might also be controlled by an intramolecular mechanism. These results indicate that an individual receptor molecule has the potential to function as a transmembrane signal transducer.

  6. Fluoxetine regulates cell growth inhibition of interferon-α.

    PubMed

    Lin, Yu-Min; Yu, Bu-Chin; Chiu, Wen-Tai; Sun, Hung-Yu; Chien, Yu-Chieh; Su, Hui-Chen; Yen, Shu-Yang; Lai, Hsin-Wen; Bai, Chyi-Huey; Young, Kung-Chia; Tsao, Chiung-Wen

    2016-10-01

    Fluoxetine, a well-known anti-depression agent, may act as a chemosensitizer to assist and promote cancer therapy. However, how fluoxetine regulates cellular signaling to enhance cellular responses against tumor cell growth remains unclear. In the present study, addition of fluoxetine promoted growth inhibition of interferon-alpha (IFN-α) in human bladder carcinoma cells but not in normal uroepithelial cells through lessening the IFN-α-induced apoptosis but switching to cause G1 arrest, and maintaining the IFN-α-mediated reduction in G2/M phase. Activations and signal transducer and transactivator (STAT)-1 and peroxisome proliferator-activated receptor alpha (PPAR-α) were involved in this process. Chemical inhibitions of STAT-1 or PPAR-α partially rescued bladder carcinoma cells from IFN-α-mediated growth inhibition via blockades of G1 arrest, cyclin D1 reduction, p53 downregulation and p27 upregulation in the presence of fluoxetine. However, the functions of both proteins were not involved in the control of fluoxetine over apoptosis and maintained the declined G2/M phase of IFN-α. These results indicated that activation of PPAR-α and STAT-1 participated, at least in part, in growth inhibition of IFN-α in the presence of fluoxetine.

  7. Controlled Crystal Grain Growth in Mixed Cation-Halide Perovskite by Evaporated Solvent Vapor Recycling Method for High Efficiency Solar Cells.

    PubMed

    Numata, Youhei; Kogo, Atsushi; Udagawa, Yosuke; Kunugita, Hideyuki; Ema, Kazuhiro; Sanehira, Yoshitaka; Miyasaka, Tsutomu

    2017-06-07

    We developed a new and simple solvent vapor-assisted thermal annealing (VA) procedure which can reduce grain boundaries in a perovskite film for fabricating highly efficient perovskite solar cells (PSCs). By recycling of solvent molecules evaporated from an as-prepared perovskite film as a VA vapor source, named the pot-roast VA (PR-VA) method, finely controlled and reproducible device fabrication was achieved for formamidinium (FA) and methylammonium (MA) mixed cation-halide perovskite (FAPbI3)0.85(MAPbBr3)0.15. The mixed perovskite was crystallized on a low-temperature prepared brookite TiO2 mesoporous scaffold. When exposed to very dilute solvent vapor, small grains in the perovskite film gradually unified into large grains, resulting in grain boundaries which were highly reduced and improvement of photovoltaic performance in PSC. PR-VA-treated large grain perovskite absorbers exhibited stable photocurrent-voltage performance with high fill factor and suppressed hysteresis, achieving the best conversion efficiency of 18.5% for a 5 × 5 mm(2) device and 15.2% for a 1.0 × 1.0 cm(2) device.

  8. Mesenchymal stem cell like (MSCl) cells generated from human embryonic stem cells support pluripotent cell growth

    SciTech Connect

    Varga, Nora; Vereb, Zoltan; Rajnavoelgyi, Eva; Nemet, Katalin; Uher, Ferenc; Sarkadi, Balazs; Apati, Agota

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer MSC like cells were derived from hESC by a simple and reproducible method. Black-Right-Pointing-Pointer Differentiation and immunosuppressive features of MSCl cells were similar to bmMSC. Black-Right-Pointing-Pointer MSCl cells as feeder cells support the undifferentiated growth of hESC. -- Abstract: Mesenchymal stem cell like (MSCl) cells were generated from human embryonic stem cells (hESC) through embryoid body formation, and isolated by adherence to plastic surface. MSCl cell lines could be propagated without changes in morphological or functional characteristics for more than 15 passages. These cells, as well as their fluorescent protein expressing stable derivatives, efficiently supported the growth of undifferentiated human embryonic stem cells as feeder cells. The MSCl cells did not express the embryonic (Oct4, Nanog, ABCG2, PODXL, or SSEA4), or hematopoietic (CD34, CD45, CD14, CD133, HLA-DR) stem cell markers, while were positive for the characteristic cell surface markers of MSCs (CD44, CD73, CD90, CD105). MSCl cells could be differentiated toward osteogenic, chondrogenic or adipogenic directions and exhibited significant inhibition of mitogen-activated lymphocyte proliferation, and thus presented immunosuppressive features. We suggest that cultured MSCl cells can properly model human MSCs and be applied as efficient feeders in hESC cultures.

  9. In vitro plant cell growth in microgravity and on clinostat.

    PubMed

    Laurinavicius, R; Kenstaviciene, P; Rupainiene, O; Necitailo, G

    1994-01-01

    For the study of gravity's role in the processes of plant cell differentiation in-vitro, a model "seed-seedling-callus" has been used. Experiments were carried out on board the orbital stations Salyut-7 and Mir as well as on clinostat. They lasted from 18 to 72 days. It was determined that the exclusion of a one-sided action of gravity vector by means of clinostat and spaceflight conditions does not impede the formation and growth of callus tissue; however, at cell and subcellular levels structural and functional changes do take place. No significant changes were observed either on clinostat or in space concerning the accumulation of fresh biomass, while the percentage of dry material in space is lower than in control. Both in microgravity (MG) and in control, even after 72 days of growth, cells with a normally developed ultrastructure are present. In space, however, callus tissue more often contains cells in which the cross-section area of a cell, a nuclei and of mitochondria are smaller and the vacuole area--bigger than in controls. In microgravity a considerable decrease in the number of starch-containing cells and a reduction in the mean area of starch grains in amyloplasts is observed. In space the amount of soluble proteins in callus tissue is 1.5 times greater than in control. However, no differences were observed in fractions when separated by the SDS-PAGE method. In microgravity the changes in cell wall material components was noted. In the space-formed callus changes in the concentration of ions K, Na, Mg, Ca and P were observed. However, the direction of these changes depends on the age of callus. Discussed are the possible reasons for modification of morphological and metabolic parameters of callus cells when grown under changed gravity conditions.

  10. Target of Rapamycin (TOR) in Nutrient Signaling and Growth Control

    PubMed Central

    Loewith, Robbie; Hall, Michael N.

    2011-01-01

    TOR (Target Of Rapamycin) is a highly conserved protein kinase that is important in both fundamental and clinical biology. In fundamental biology, TOR is a nutrient-sensitive, central controller of cell growth and aging. In clinical biology, TOR is implicated in many diseases and is the target of the drug rapamycin used in three different therapeutic areas. The yeast Saccharomyces cerevisiae has played a prominent role in both the discovery of TOR and the elucidation of its function. Here we review the TOR signaling network in S. cerevisiae. PMID:22174183

  11. Effects of Varied pH, Growth Rate and Temperature using Controlled fermentation and Batch culture on Matrix Assisted Laser Desorption/Ionization Whole Cell Protein Fingerprints.

    SciTech Connect

    Wunschel, David S.; Hill, Eric A.; Mclean, Jeffrey S.; Jarman, Kristin H.; Gorby, Yuri A.; Valentine, Nancy B.; Wahl, Karen L.

    2005-09-01

    Rapid identification of microorganisms using matrix assisted laser desorption/ionization (MALDI) is a rapidly growing area of research due to the minimal sample preparation, speed of analysis and broad applicability of the technique. This approach relies on protein markers to identify microorganisms. Therefore, variations in culture conditions that affect protein expression may limit the ability of MALDI-MS to correctly identify an organism. We have expanded our efforts to investigate the effects of culture conditions on MALDI-MS protein signatures to examine the effects of pH, growth rate and temperature. Continuous cultures maintained in bioreactors were used to maintain specific growth rates and pH for E. coli HB 101. Despite measurable morphological differences between growth conditions, the MALDI-MS data associated each culture with the appropriate library entry (E. coli HB 101 generated using batch culture on a LB media), independent of pH or growth rate. The lone exception was for a biofilm sample collected from one of the reactors which had no appreciable degree of association with the correct library entry. Within the data set for planktonic organisms, variations in growth rate created the largest variation between fingerprints. The effect of varying growth temperature on Y. enterocolitica was also examined. While the anticipated effects on phenotype were observed, the MALDI-MS technique provided the proper identification.

  12. Spatiotemporally controlled single cell sonoporation

    PubMed Central

    Fan, Zhenzhen; Liu, Haiyan; Mayer, Michael; Deng, Cheri X.

    2012-01-01

    This paper presents unique approaches to enable control and quantification of ultrasound-mediated cell membrane disruption, or sonoporation, at the single-cell level. Ultrasound excitation of microbubbles that were targeted to the plasma membrane of HEK-293 cells generated spatially and temporally controlled membrane disruption with high repeatability. Using whole-cell patch clamp recording combined with fluorescence microscopy, we obtained time-resolved measurements of single-cell sonoporation and quantified the size and resealing rate of pores. We measured the intracellular diffusion coefficient of cytoplasmic RNA/DNA from sonoporation-induced transport of an intercalating fluorescent dye into and within single cells. We achieved spatiotemporally controlled delivery with subcellular precision and calcium signaling in targeted cells by selective excitation of microbubbles. Finally, we utilized sonoporation to deliver calcein, a membrane-impermeant substrate of multidrug resistance protein-1 (MRP1), into HEK-MRP1 cells, which overexpress MRP1, and monitored the calcein efflux by MRP1. This approach made it possible to measure the efflux rate in individual cells and to compare it directly to the efflux rate in parental control cells that do not express MRP1. PMID:23012425

  13. Nutritional control of growth and development in yeast.

    PubMed

    Broach, James R

    2012-09-01

    Availability of key nutrients, such as sugars, amino acids, and nitrogen compounds, dictates the developmental programs and the growth rates of yeast cells. A number of overlapping signaling networks--those centered on Ras/protein kinase A, AMP-activated kinase, and target of rapamycin complex I, for instance--inform cells on nutrient availability and influence the cells' transcriptional, translational, posttranslational, and metabolic profiles as well as their developmental decisions. Here I review our current understanding of the structures of the networks responsible for assessing the quantity and quality of carbon and nitrogen sources. I review how these signaling pathways impinge on transcriptional, metabolic, and developmental programs to optimize survival of cells under different environmental conditions. I highlight the profound knowledge we have gained on the structure of these signaling networks but also emphasize the limits of our current understanding of the dynamics of these signaling networks. Moreover, the conservation of these pathways has allowed us to extrapolate our finding with yeast to address issues of lifespan, cancer metabolism, and growth control in more complex organisms.

  14. Wall relaxation and the driving forces for cell expansive growth

    NASA Technical Reports Server (NTRS)

    Cosgrove, D. J.

    1987-01-01

    When water uptake by growing cells is prevented, the turgor pressure and the tensile stress in the cell wall are reduced by continued wall loosening. This process, termed in vivo stress relaxation, provides a new way to study the dynamics of wall loosening and to measure the wall yield threshold and the physiological wall extensibility. Stress relaxation experiments indicate that wall stress supplies the mechanical driving force for wall yielding. Cell expansion also requires water absorption. The driving force for water uptake during growth is created by wall relaxation, which lowers the water potential of the expanding cells. New techniques for measuring this driving force show that it is smaller than believed previously; in elongating stems it is only 0.3 to 0.5 bar. This means that the hydraulic resistance of the water transport pathway is small and that rate of cell expansion is controlled primarily by wall loosening and yielding.

  15. Wall relaxation and the driving forces for cell expansive growth

    NASA Technical Reports Server (NTRS)

    Cosgrove, D. J.

    1987-01-01

    When water uptake by growing cells is prevented, the turgor pressure and the tensile stress in the cell wall are reduced by continued wall loosening. This process, termed in vivo stress relaxation, provides a new way to study the dynamics of wall loosening and to measure the wall yield threshold and the physiological wall extensibility. Stress relaxation experiments indicate that wall stress supplies the mechanical driving force for wall yielding. Cell expansion also requires water absorption. The driving force for water uptake during growth is created by wall relaxation, which lowers the water potential of the expanding cells. New techniques for measuring this driving force show that it is smaller than believed previously; in elongating stems it is only 0.3 to 0.5 bar. This means that the hydraulic resistance of the water transport pathway is small and that rate of cell expansion is controlled primarily by wall loosening and yielding.

  16. Wall relaxation and the driving forces for cell expansive growth.

    PubMed

    Cosgrove, D J

    1987-01-01

    When water uptake by growing cells is prevented, the turgor pressure and the tensile stress in the cell wall are reduced by continued wall loosening. This process, termed in vivo stress relaxation, provides a new way to study the dynamics of wall loosening and to measure the wall yield threshold and the physiological wall extensibility. Stress relaxation experiments indicate that wall stress supplies the mechanical driving force for wall yielding. Cell expansion also requires water absorption. The driving force for water uptake during growth is created by wall relaxation, which lowers the water potential of the expanding cells. New techniques for measuring this driving force show that it is smaller than believed previously; in elongating stems it is only 0.3 to 0.5 bar. This means that the hydraulic resistance of the water transport pathway is small and that rate of cell expansion is controlled primarily by wall loosening and yielding.

  17. Economic growth and carbon emission control

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenyu

    The question about whether environmental improvement is compatible with continued economic growth remains unclear and requires further study in a specific context. This study intends to provide insight on the potential for carbon emissions control in the absence of international agreement, and connect the empirical analysis with theoretical framework. The Chinese electricity generation sector is used as a case study to demonstrate the problem. Both social planner and private problems are examined to derive the conditions that define the optimal level of production and pollution. The private problem will be demonstrated under the emission regulation using an emission tax, an input tax and an abatement subsidy respectively. The social optimal emission flow is imposed into the private problem. To provide tractable analytical results, a Cobb-Douglas type production function is used to describe the joint production process of the desired output and undesired output (i.e., electricity and emissions). A modified Hamiltonian approach is employed to solve the system and the steady state solutions are examined for policy implications. The theoretical analysis suggests that the ratio of emissions to desired output (refer to 'emission factor'), is a function of productive capital and other parameters. The finding of non-constant emission factor shows that reducing emissions without further cutting back the production of desired outputs is feasible under some circumstances. Rather than an ad hoc specification, the optimal conditions derived from our theoretical framework are used to examine the relationship between desired output and emission level. Data comes from the China Statistical Yearbook and China Electric Power Yearbook and provincial information of electricity generation for the year of 1993-2003 are used to estimate the Cobb-Douglas type joint production by the full information maximum likelihood (FIML) method. The empirical analysis shed light on the optimal

  18. Imatinib alters cell viability but not growth factors levels in TM4 Sertoli cells

    PubMed Central

    Hashemnia, Seyyed Mohammad Reza; Atari-Hajipirloo, Somayeh; Roshan-Milani, Shiva; Valizadeh, Nasim; Mahabadi, Sonya; Kheradmand, Fatemeh

    2016-01-01

    Background: The anticancer agent imatinib (IM) is a small molecular analog of ATP that inhibits tyrosine kinase activity of platelet derived growth factors (PDGFs) and stem cell factor (SCF) receptor in cancer cells. However these factors have a key role in regulating growth and development of normal Sertoli, Leydig and germ cells. Objective: The aim of this study was to determine cell viability, PDGF and SCF levels in mouse normal Sertoli cells exposed to IM. Materials and Methods: In this experimental study, the mouse TM4 Sertoli cells were treated with 0, 2.5, 5, 10 and 20 μM IM for 2, 4 or 6 days. The cell viability and growth factors levels were assessed by MTT and ELISA methods, respectively. For statistical analysis, One-Way ANOVA was performed. Results: IM showed significant decrease in Sertoli cell viability compared to control group (p=0.001). However, IM increased PDGF and SCF level insignificantly (p>0.05). Conclusion: Results suggested that IM treatment induced a dose dependent reduction of cell viability in Sertoli cells. It seems that treatment with this anticancer drug is involved in the fertility process. Further studies are needed to evaluate the role of PDGF and SCF in this cell. PMID:27738659

  19. Dynamical Allocation of Cellular Resources as an Optimal Control Problem: Novel Insights into Microbial Growth Strategies

    PubMed Central

    Giordano, Nils; Mairet, Francis; Gouzé, Jean-Luc

    2016-01-01

    Microbial physiology exhibits growth laws that relate the macromolecular composition of the cell to the growth rate. Recent work has shown that these empirical regularities can be derived from coarse-grained models of resource allocation. While these studies focus on steady-state growth, such conditions are rarely found in natural habitats, where microorganisms are continually challenged by environmental fluctuations. The aim of this paper is to extend the study of microbial growth strategies to dynamical environments, using a self-replicator model. We formulate dynamical growth maximization as an optimal control problem that can be solved using Pontryagin’s Maximum Principle. We compare this theoretical gold standard with different possible implementations of growth control in bacterial cells. We find that simple control strategies enabling growth-rate maximization at steady state are suboptimal for transitions from one growth regime to another, for example when shifting bacterial cells to a medium supporting a higher growth rate. A near-optimal control strategy in dynamical conditions is shown to require information on several, rather than a single physiological variable. Interestingly, this strategy has structural analogies with the regulation of ribosomal protein synthesis by ppGpp in the enterobacterium Escherichia coli. It involves sensing a mismatch between precursor and ribosome concentrations, as well as the adjustment of ribosome synthesis in a switch-like manner. Our results show how the capability of regulatory systems to integrate information about several physiological variables is critical for optimizing growth in a changing environment. PMID:26958858

  20. Long-term growth data of Escherichia coli at a single-cell level

    PubMed Central

    Tanouchi, Yu; Pai, Anand; Park, Heungwon; Huang, Shuqiang; Buchler, Nicolas E.; You, Lingchong

    2017-01-01

    Long-term, single-cell measurement of bacterial growth is extremely valuable information, particularly in the study of homeostatic aspects such as cell-size and growth rate control. Such measurement has recently become possible due to the development of microfluidic technology. Here we present data from single-cell measurements of Escherichia coli growth over 70 generations obtained for three different growth conditions. The data were recorded every minute, and contain time course data of cell length and fluorescent intensity of constitutively expressed yellow fluorescent protein. PMID:28350394

  1. Insulin-Like Growth Factor 1 Receptor and p38 Mitogen-Activated Protein Kinase Signals Inversely Regulate Signal Transducer and Activator of Transcription 3 Activity to Control Human Dental Pulp Stem Cell Quiescence, Propagation, and Differentiation

    PubMed Central

    Vandomme, Jerome; Touil, Yasmine; Ostyn, Pauline; Olejnik, Cecile; Flamenco, Pilar; El Machhour, Raja; Segard, Pascaline; Masselot, Bernadette; Bailliez, Yves; Formstecher, Pierre

    2014-01-01

    Dental pulp stem cells (DPSCs) remain quiescent until activated in response to severe dental pulp damage. Once activated, they exit quiescence and enter regenerative odontogenesis, producing reparative dentin. The factors and signaling molecules that control the quiescence/activation and commitment to differentiation of human DPSCs are not known. In this study, we determined that the inhibition of insulin-like growth factor 1 receptor (IGF-1R) and p38 mitogen-activated protein kinase (p38 MAPK) signaling commonly activates DPSCs and promotes their exit from the G0 phase of the cell cycle as well as from the pyronin Ylow stem cell compartment. The inhibition of these two pathways, however, inversely determines DPSC fate. In contrast to p38 MAPK inhibitors, IGF-1R inhibitors enhance dental pulp cell sphere-forming capacity and reduce the cells' colony-forming capacity without inducing cell death. The inverse cellular changes initiated by IGF-1R and p38 MAPK inhibitors were accompanied by inverse changes in the levels of active signal transducer and activator of transcription 3 (STAT3) factor, inactive glycogen synthase kinase 3, and matrix extracellular phosphoglycoprotein, a marker of early odontoblast differentiation. Our data suggest that there is cross talk between the IGF-1R and p38 MAPK signaling pathways in DPSCs and that the signals provided by these pathways converge at STAT3 and inversely regulate its activity to maintain quiescence or to promote self-renewal and differentiation of the cells. We propose a working model that explains the possible interactions between IGF-1R and p38 MAPK at the molecular level and describes the cellular consequences of these interactions. This model may inspire further fundamental study and stimulate research on the clinical applications of DPSC in cellular therapy and tissue regeneration. PMID:24266654

  2. Insulin-like growth factor 1 receptor and p38 mitogen-activated protein kinase signals inversely regulate signal transducer and activator of transcription 3 activity to control human dental pulp stem cell quiescence, propagation, and differentiation.

    PubMed

    Vandomme, Jerome; Touil, Yasmine; Ostyn, Pauline; Olejnik, Cecile; Flamenco, Pilar; El Machhour, Raja; Segard, Pascaline; Masselot, Bernadette; Bailliez, Yves; Formstecher, Pierre; Polakowska, Renata

    2014-04-15

    Dental pulp stem cells (DPSCs) remain quiescent until activated in response to severe dental pulp damage. Once activated, they exit quiescence and enter regenerative odontogenesis, producing reparative dentin. The factors and signaling molecules that control the quiescence/activation and commitment to differentiation of human DPSCs are not known. In this study, we determined that the inhibition of insulin-like growth factor 1 receptor (IGF-1R) and p38 mitogen-activated protein kinase (p38 MAPK) signaling commonly activates DPSCs and promotes their exit from the G0 phase of the cell cycle as well as from the pyronin Y(low) stem cell compartment. The inhibition of these two pathways, however, inversely determines DPSC fate. In contrast to p38 MAPK inhibitors, IGF-1R inhibitors enhance dental pulp cell sphere-forming capacity and reduce the cells' colony-forming capacity without inducing cell death. The inverse cellular changes initiated by IGF-1R and p38 MAPK inhibitors were accompanied by inverse changes in the levels of active signal transducer and activator of transcription 3 (STAT3) factor, inactive glycogen synthase kinase 3, and matrix extracellular phosphoglycoprotein, a marker of early odontoblast differentiation. Our data suggest that there is cross talk between the IGF-1R and p38 MAPK signaling pathways in DPSCs and that the signals provided by these pathways converge at STAT3 and inversely regulate its activity to maintain quiescence or to promote self-renewal and differentiation of the cells. We propose a working model that explains the possible interactions between IGF-1R and p38 MAPK at the molecular level and describes the cellular consequences of these interactions. This model may inspire further fundamental study and stimulate research on the clinical applications of DPSC in cellular therapy and tissue regeneration.

  3. TAK1 control of cell death

    PubMed Central

    Mihaly, S R; Ninomiya-Tsuji, J; Morioka, S

    2014-01-01

    Programmed cell death, a physiologic process for removing cells, is critically important in normal development and for elimination of damaged cells. Conversely, unattended cell death contributes to a variety of human disease pathogenesis. Thus, precise understanding of molecular mechanisms underlying control of cell death is important and relevant to public health. Recent studies emphasize that transforming growth factor-β-activated kinase 1 (TAK1) is a central regulator of cell death and is activated through a diverse set of intra- and extracellular stimuli. The physiologic importance of TAK1 and TAK1-binding proteins in cell survival and death has been demonstrated using a number of genetically engineered mice. These studies uncover an indispensable role of TAK1 and its binding proteins for maintenance of cell viability and tissue homeostasis in a variety of organs. TAK1 is known to control cell viability and inflammation through activating downstream effectors such as NF-κB and mitogen-activated protein kinases (MAPKs). It is also emerging that TAK1 regulates cell survival not solely through NF-κB but also through NF-κB-independent pathways such as oxidative stress and receptor-interacting protein kinase 1 (RIPK1) kinase activity-dependent pathway. Moreover, recent studies have identified TAK1's seemingly paradoxical role to induce programmed necrosis, also referred to as necroptosis. This review summarizes the consequences of TAK1 deficiency in different cell and tissue types from the perspective of cell death and also focuses on the mechanism by which TAK1 complex inhibits or promotes programmed cell death. This review serves to synthesize our current understanding of TAK1 in cell survival and death to identify promising directions for future research and TAK1's potential relevance to human disease pathogenesis. PMID:25146924

  4. Skeletal muscle–specific eukaryotic translation initiation factor 2α phosphorylation controls amino acid metabolism and fibroblast growth factor 21–mediated non–cell-autonomous energy metabolism

    PubMed Central

    Miyake, Masato; Nomura, Akitoshi; Ogura, Atsushi; Takehana, Kenji; Kitahara, Yoshihiro; Takahara, Kazuna; Tsugawa, Kazue; Miyamoto, Chinobu; Miura, Naoko; Sato, Ryosuke; Kurahashi, Kiyoe; Harding, Heather P.; Oyadomari, Miho; Ron, David; Oyadomari, Seiichi

    2016-01-01

    The eukaryotic translation initiation factor 2α (eIF2α) phosphorylation-dependent integrated stress response (ISR), a component of the unfolded protein response, has long been known to regulate intermediary metabolism, but the details are poorly worked out. We report that profiling of mRNAs of transgenic mice harboring a ligand-activated skeletal muscle–specific derivative of the eIF2α protein kinase R-like ER kinase revealed the expected up-regulation of genes involved in amino acid biosynthesis and transport but also uncovered the induced expression and secretion of a myokine, fibroblast growth factor 21 (FGF21), that stimulates energy consumption and prevents obesity. The link between the ISR and FGF21 expression was further reinforced by the identification of a small-molecule ISR activator that promoted Fgf21 expression in cell-based screens and by implication of the ISR-inducible activating transcription factor 4 in the process. Our findings establish that eIF2α phosphorylation regulates not only cell-autonomous proteostasis and amino acid metabolism, but also affects non–cell-autonomous metabolic regulation by induced expression of a potent myokine.—Miyake, M., Nomura, A., Ogura, A., Takehana, K., Kitahara, Y., Takahara, K., Tsugawa, K., Miyamoto, C., Miura, N., Sato, R., Kurahashi, K., Harding, H. P., Oyadomari, M., Ron, D., Oyadomari, S. Skeletal muscle–specific eukaryotic translation initiation factor 2α phosphorylation controls amino acid metabolism and fibroblast growth factor 21–mediated non–cell-autonomous energy metabolism. PMID:26487695

  5. Blockade of Programmed Death 1 Augments the Ability of Human T Cells Engineered to Target NY-ESO-1 to Control Tumor Growth after Adoptive Transfer.

    PubMed

    Moon, Edmund K; Ranganathan, Raghuveer; Eruslanov, Evgeniy; Kim, Soyeon; Newick, Kheng; O'Brien, Shaun; Lo, Albert; Liu, Xiaojun; Zhao, Yangbing; Albelda, Steven M

    2016-01-15

    Tumor-infiltrating lymphocytes (TILs) become hypofunctional, although the mechanisms are not clear. Our goal was to generate a model of human tumor-induced TIL hypofunction to study mechanisms and to test anti-human therapeutics. We transduced human T cells with a published, optimized T-cell receptor (TCR) that is directed to a peptide within the cancer testis antigen, NY-ESO-1. After demonstrating antigen-specific in vitro activity, these cells were used to target a human lung cancer line that expressed NY-ESO-1 in the appropriate HLA context growing in immunodeficient mice. The ability of anti-PD1 antibody to augment efficacy was tested. Injection of transgenic T cells had some antitumor activity, but did not eliminate the tumors. The injected T cells became profoundly hypofunctional accompanied by upregulation of PD1, Tim3, and Lag3 with coexpression of multiple inhibitory receptors in a high percentage of cells. This model allowed us to test reagents targeted specifically to human T cells. We found that injections of an anti-PD1 antibody in combination with T cells led to decreased TIL hypofunction and augmented the efficacy of the adoptively transferred T cells. This model offers a platform for preclinical testing of adjuvant immunotherapeutics targeted to human T cells prior to transition to the bedside. Because the model employs engineering of human T cells with a TCR clone instead of a CAR, it allows for study of the biology of tumor-reactive TILs that signal through an endogenous TCR. The lessons learned from TCR-engineered TILs can thus be applied to tumor-reactive TILs. ©2015 American Association for Cancer Research.

  6. [Stem cells and growth factors in wound healing].

    PubMed

    Pikuła, Michał; Langa, Paulina; Kosikowska, Paulina; Trzonkowski, Piotr

    2015-01-02

    Wound healing is a complex process which depends on the presence of various types of cells, growth factors, cytokines and the elements of extracellular matrix. A wound is a portal of entry for numerous pathogens, therefore during the evolution wound healing process has formed very early, being critical for the survival of every individual. Stem cells, which give rise to their early descendants progenitor cells and subsequently differentiated cells, play a specific role in the process of wound healing. Among the most important cells which take part in wound healing the following cells need to be distinguished: epidermal stem cells, dermal precursor of fibroblasts, adipose-derived stem cells as well as bone marrow cells. The activity of these cells is strictly regulated by various growth factors, inter alia epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), transforming growth factor (TGF), vascular endothelial growth factor (VEGF). Any disorders in functioning of stem cells and biological activity of growth factors may lead to the defects in wound healing, for instance delayed wound healing or creation of hypertrophic scars. Therefore, knowledge concerning the mechanisms of wound healing is extremely essential from clinical point of view. In this review the current state of the knowledge of the role of stem cells and growth factors in the process of wound healing has been presented. Moreover, some clinical aspects of wound healing as well as the possibility of the therapy based on stem cells and growth factors have included.

  7. Controlled Nucleation and Growth of Semiconducting Diamond

    DTIC Science & Technology

    1992-12-18

    analytical measurements of film growth have been coupled with novel precursor chemistry to study the effect of precursor chemical structure on the...efficiency of diamond film nucleation and growth. The goal is to optimize source gases and substrate surface preparation methods for both doped and...undoped diamond film nucleation and growth, enabling the use of diamond in field emission, semiconductor, and optoelectronic applications. "Surface

  8. Stochastic modeling of cell growth with symmetric or asymmetric division

    NASA Astrophysics Data System (ADS)

    Marantan, Andrew; Amir, Ariel

    2016-07-01

    We consider a class of biologically motivated stochastic processes in which a unicellular organism divides its resources (volume or damaged proteins, in particular) symmetrically or asymmetrically between its progeny. Assuming the final amount of the resource is controlled by a growth policy and subject to additive and multiplicative noise, we derive the recursive integral equation describing the evolution of the resource distribution over subsequent generations and use it to study the properties of stable resource distributions. We find conditions under which a unique stable resource distribution exists and calculate its moments for the class of affine linear growth policies. Moreover, we apply an asymptotic analysis to elucidate the conditions under which the stable distribution (when it exists) has a power-law tail. Finally, we use the results of this asymptotic analysis along with the moment equations to draw a stability phase diagram for the system that reveals the counterintuitive result that asymmetry serves to increase stability while at the same time widening the stable distribution. We also briefly discuss how cells can divide damaged proteins asymmetrically between their progeny as a form of damage control. In the appendixes, motivated by the asymmetric division of cell volume in Saccharomyces cerevisiae, we extend our results to the case wherein mother and daughter cells follow different growth policies.

  9. Controlled reflectance solar cell

    SciTech Connect

    Dill, H.G.; Lillington, D.R.

    1989-06-13

    A solar cell is described comprising: A semiconductor body having a front layer of a first conductivity type and an adjacent back layer of a second conductivity type opposite of the first conductivity type. The front and back layers form front and back major surfaces, respectively the semiconductor body further having openings through the back major surface and back layer which form recesses extending to the front layer. The recesses having walls which are doped to the first conductivity type; a first electrical contact disposed in the recesses making electrical contact the first conductivity type layer; and a second electrical contact disposed on the back major surface making electrical contact to the second conductivity type layer.

  10. Nutritional Control of Growth and Development in Yeast

    PubMed Central

    Broach, James R.

    2012-01-01

    Availability of key nutrients, such as sugars, amino acids, and nitrogen compounds, dictates the developmental programs and the growth rates of yeast cells. A number of overlapping signaling networks—those centered on Ras/protein kinase A, AMP-activated kinase, and target of rapamycin complex I, for instance—inform cells on nutrient availability and influence the cells’ transcriptional, translational, posttranslational, and metabolic profiles as well as their developmental decisions. Here I review our current understanding of the structures of the networks responsible for assessing the quantity and quality of carbon and nitrogen sources. I review how these signaling pathways impinge on transcriptional, metabolic, and developmental programs to optimize survival of cells under different environmental conditions. I highlight the profound knowledge we have gained on the structure of these signaling networks but also emphasize the limits of our current understanding of the dynamics of these signaling networks. Moreover, the conservation of these pathways has allowed us to extrapolate our finding with yeast to address issues of lifespan, cancer metabolism, and growth control in more complex organisms. PMID:22964838

  11. Using chemical genomics to study cell wall formation and cell growth in Arabidopsis thaliana and Penium margaritaceum.

    PubMed

    Worden, N; Esteve, V Esteva; Domozych, D S; Drakakaki, G

    2015-01-01

    The cell wall is directly involved in cell growth, and its ability to loosen and rearrange allows for cell expansion through the existing turgor pressure. Thus, information on cell wall deposition and rearrangement can provide insights into the overall plant growth. This chapter describes two methods that can be used to evaluate cell expansion (1) in the model plant Arabidopsis thaliana and (2) the model alga Penium margaritaceum. These methods are further used to screen for small molecules that induce cell growth phenotypic changes affecting cell wall. Identification of such small molecules is beneficial due to their posttranslational mechanism of action that can be controlled in a temporal and spatial manner. Chemical genomics has the ability to overcome issues of genetic redundancy and lethality, which can hinder traditional genetic methods. The identification of small molecules in these screens will provide useful information on plant cell wall biology and overall plant growth.

  12. Stoichiometric controls of mercury dilution by growth

    PubMed Central

    Karimi, Roxanne; Chen, Celia Y.; Pickhardt, Paul C.; Fisher, Nicholas S.; Folt, Carol L.

    2007-01-01

    Rapid growth could significantly reduce methylmercury (MeHg) concentrations in aquatic organisms by causing a greater than proportional gain in biomass relative to MeHg (somatic growth dilution). We hypothesized that rapid growth from the consumption of high-quality algae, defined by algal nutrient stoichiometry, reduces MeHg concentrations in zooplankton, a major source of MeHg for lake fish. Using a MeHg radiotracer, we measured changes in MeHg concentrations, growth and ingestion rates in juvenile Daphnia pulex fed either high (C:P = 139) or low-quality (C:P = 1317) algae (Ankistrodesmus falcatus) for 5 d. We estimated Daphnia steady-state MeHg concentrations, using a biokinetic model parameterized with experimental rates. Daphnia MeHg assimilation efficiencies (≈95%) and release rates (0.04 d−1) were unaffected by algal nutrient quality. However, Daphnia growth rate was 3.5 times greater when fed high-quality algae, resulting in pronounced somatic growth dilution. Steady-state MeHg concentrations in Daphnia that consumed high-quality algae were one-third those of Daphnia that consumed low-quality algae due to higher growth and slightly lower ingestion rates. Our findings show that rapid growth from high-quality food consumption can significantly reduce the accumulation and trophic transfer of MeHg in freshwater food webs. PMID:17456601

  13. Stoichiometric controls of mercury dilution by growth.

    PubMed

    Karimi, Roxanne; Chen, Celia Y; Pickhardt, Paul C; Fisher, Nicholas S; Folt, Carol L

    2007-05-01

    Rapid growth could significantly reduce methylmercury (MeHg) concentrations in aquatic organisms by causing a greater than proportional gain in biomass relative to MeHg (somatic growth dilution). We hypothesized that rapid growth from the consumption of high-quality algae, defined by algal nutrient stoichiometry, reduces MeHg concentrations in zooplankton, a major source of MeHg for lake fish. Using a MeHg radiotracer, we measured changes in MeHg concentrations, growth and ingestion rates in juvenile Daphnia pulex fed either high (C:P = 139) or low-quality (C:P = 1317) algae (Ankistrodesmus falcatus) for 5 d. We estimated Daphnia steady-state MeHg concentrations, using a biokinetic model parameterized with experimental rates. Daphnia MeHg assimilation efficiencies (approximately 95%) and release rates (0.04 d(-1)) were unaffected by algal nutrient quality. However, Daphnia growth rate was 3.5 times greater when fed high-quality algae, resulting in pronounced somatic growth dilution. Steady-state MeHg concentrations in Daphnia that consumed high-quality algae were one-third those of Daphnia that consumed low-quality algae due to higher growth and slightly lower ingestion rates. Our findings show that rapid growth from high-quality food consumption can significantly reduce the accumulation and trophic transfer of MeHg in freshwater food webs.

  14. Cell size control - a mechanism for maintaining fitness and function.

    PubMed

    Miettinen, Teemu P; Caldez, Matias J; Kaldis, Philipp; Björklund, Mikael

    2017-09-01

    The maintenance of cell size homeostasis has been studied for years in different cellular systems. With the focus on 'what regulates cell size', the question 'why cell size needs to be maintained' has been largely overlooked. Recent evidence indicates that animal cells exhibit nonlinear cell size dependent growth rates and mitochondrial metabolism, which are maximal in intermediate sized cells within each cell population. Increases in intracellular distances and changes in the relative cell surface area impose biophysical limitations on cells, which can explain why growth and metabolic rates are maximal in a specific cell size range. Consistently, aberrant increases in cell size, for example through polyploidy, are typically disadvantageous to cellular metabolism, fitness and functionality. Accordingly, cellular hypertrophy can potentially predispose to or worsen metabolic diseases. We propose that cell size control may have emerged as a guardian of cellular fitness and metabolic activity. © 2017 WILEY Periodicals, Inc.

  15. Nonlinear Growth Kinetics of Breast Cancer Stem Cells: Implications for Cancer Stem Cell Targeted Therapy

    NASA Astrophysics Data System (ADS)

    Liu, Xinfeng; Johnson, Sara; Liu, Shou; Kanojia, Deepak; Yue, Wei; Singn, Udai; Wang, Qian; Wang, Qi; Nie, Qing; Chen, Hexin

    2013-08-01

    Cancer stem cells (CSCs) have been identified in primary breast cancer tissues and cell lines. The CSC population varies widely among cancerous tissues and cell lines, and is often associated with aggressive breast cancers. Despite of intensive research, how the CSC population is regulated within a tumor is still not well understood so far. In this paper, we present a mathematical model to explore the growth kinetics of CSC population both in vitro and in vivo. Our mathematical models and supporting experiments suggest that there exist non-linear growth kinetics of CSCs and negative feedback mechanisms to control the balance between the population of CSCs and that of non-stem cancer cells. The model predictions can help us explain a few long-standing questions in the field of cancer stem cell research, and can be potentially used to predict the efficicacy of anti-cancer therapy.

  16. Rat Prolactinoma cell growth regulation by Epidermal Growth Factor receptor ligands

    PubMed Central

    Vlotides, George; Siegel, Emily; Donangelo, Ines; Gutman, Shiri; Ren, Song-Guang; Melmed, Shlomo

    2008-01-01

    Epidermal growth factor (EGF) regulates pituitary development, hormone synthesis and cell proliferation. Although ErbB receptor family members are expressed in pituitary tumors, effects of EGF signaling on pituitary tumors are not known. Immunoprecipitation and Western blot confirmed EGFR and p185c-neu protein expression in GH3 lacto-somatotroph but not in ACTH-secreting AtT20 pituitary tumor cells. EGF (5 nM) selectively enhanced baseline (~ 4-fold) and serum-induced (> 6-fold) PRL mRNA levels, while gefitinib, an EGFR antagonist, suppressed serum-induced cell proliferation and Pttg1 expression, blocked PRL gene expression, and reversed EGF-mediated somatotroph-lactotroph phenotype switching. Downstream EGFR signaling by ERK, but not PI3K or PKC, mediated the gefitinib-response. Tumors in athymic mice implanted sc with GH3 cells resulted in weight gain accompanied by increased serum PRL, GH and IGF-I levels. Gefitinib decreased tumor volumes and peripheral hormone levels by ~ 30% and restored normal mouse body weight patterns. Mice treated with gefitinib exhibited decreased tumor tissue ERK1/2 phosphorylation and downregulated tumor PRL and Pttg1 mRNA abundance. These results show that EGFR inhibition controls tumor growth and PRL secretion in experimental lacto-somatotroph tumors. EGFR inhibitors could therefore be useful for control of PRL secretion and tumor load in prolactinomas resistant to dopaminergic treatment, or for those prolactinomas undergoing rare malignant transformation. PMID:18676863

  17. Identification of a Soluble Factor that Induces Cell Death and Growth Inhibition in Prostate Carcinoma Cells

    DTIC Science & Technology

    2010-02-01

    person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number...investigation based upon their abundance, secretary potential and reported roles in cell growth control (these proteins are listed in Table 1 in this report...i.e., calcyclin, calvasculin, ubiquitin carboxyl-terminal hydrolase isozyme L1, transgelin-3, odorant -binding protein 2a precursor, tubulin-specific

  18. Control of Drosophila wing growth by the vestigial quadrant enhancer.

    PubMed

    Zecca, Myriam; Struhl, Gary

    2007-08-01

    Following segregation of the Drosophila wing imaginal disc into dorsal (D) and ventral (V) compartments, the wing primordium is specified by activity of the selector gene vestigial (vg). In the accompanying paper, we present evidence that vg expression is itself driven by three distinct inputs: (1) short-range DSL (Delta/Serrate/LAG-2)-Notch signaling across the D-V compartment boundary; (2) long-range Wg signaling from cells abutting the D-V compartment boundary; and (3) a short-range signal sent by vg-expressing cells that entrains neighboring cells to upregulate vg in response to Wg. Furthermore, we showed that these inputs define a feed-forward mechanism of vg autoregulation that initiates in D-V border cells and propagates from cell to cell by reiterative cycles of vg upregulation. Here, we provide evidence that this feed-forward mechanism is required for normal wing growth and is mediated by two distinct enhancers in the vg gene. The first is a newly defined ;priming' enhancer (PE), that provides cryptic, low levels of Vg in most or all cells of the wing disc. The second is the previously defined quadrant enhancer (QE), which we show is activated by the combined action of Wg and the short-range vg-dependent entraining signal, but only if the responding cells are already primed by low-level Vg activity. Thus, entrainment and priming constitute distinct signaling and responding events in the Wg-dependent feed-forward circuit of vg autoregulation mediated by the QE. We posit that Wg controls the expansion of the wing primordium following D-V segregation by fueling this autoregulatory mechanism.

  19. Milk stimulates growth of prostate cancer cells in culture.

    PubMed

    Tate, Patricia L; Bibb, Robert; Larcom, Lyndon L

    2011-11-01

    Concern has been expressed about the fact that cows' milk contains estrogens and could stimulate the growth of hormone-sensitive tumors. In this study, organic cows' milk and two commercial substitutes were digested in vitro and tested for their effects on the growth of cultures of prostate and breast cancer cells. Cows' milk stimulated the growth of LNCaP prostate cancer cells in each of 14 separate experiments, producing an average increase in growth rate of over 30%. In contrast, almond milk suppressed the growth of these cells by over 30%. Neither cows' milk nor almond milk affected the growth of MCF-7 breast cancer cells or AsPC-1 pancreatic cancer cells significantly. Soy milk increased the growth rate of the breast cancer cells. These data indicate that prostate and breast cancer patients should be cautioned about the possible promotional effects of commercial dairy products and their substitutes.

  20. Role of ovarian theca and granulosa cell interaction in hormone productionand cell growth during the bovine follicular maturation process.

    PubMed

    Yada, H; Hosokawa, K; Tajima, K; Hasegawa, Y; Kotsuji, F

    1999-12-01

    We have investigated the possible role of theca and granulosa cell interaction in the control of the hormone-producing activity and growth of granulosa and theca cells during bovine ovarian follicular development, using a coculture system in which granulosa and theca cells were grown on opposite sides of a collagen membrane. When follicular cells were isolated from small follicles (3-5 mm), theca cells reduced estradiol, progesterone, and inhibin production by granulosa cells to 14 +/- 5%, 64 +/- 6%, and 27 +/- 4%, respectively, of the production by granulosa cells cultured alone. On the other hand, when the cells were isolated from large follicles (15-18 mm), theca cells increased these levels to 253 +/- 34%, 156 +/- 24%, and 287 +/- 45%, respectively. Theca cells did not affect the growth of granulosa cells. Androstenedione production by theca cells was augmented by granulosa cells to 861 +/- 190% (in small follicles) and 1298 +/- 414% (in large follicles), respectively. The growth of theca cells was also augmented by granulosa cells (small follicle, 210 +/- 43%, and large follicle, 194 +/- 24%, respectively). These results indicate that theca cells secrete factor(s) inhibiting the differentiation of immature while promoting that of matured granulosa cells; they also suggest that granulosa cells secrete factor(s) promoting both the differentiation and growth of theca cells throughout the follicular maturation process.

  1. Optical measurement of cycle-dependent cell growth.

    PubMed

    Mir, Mustafa; Wang, Zhuo; Shen, Zhen; Bednarz, Michael; Bashir, Rashid; Golding, Ido; Prasanth, Supriya G; Popescu, Gabriel

    2011-08-09

    Determining the growth patterns of single cells offers answers to some of the most elusive questions in contemporary cell biology: how cell growth is regulated and how cell size distributions are maintained. For example, a linear growth in time implies that there is no regulation required to maintain homeostasis; an exponential pattern indicates the opposite. Recently, there has been great effort to measure single cells using microelectromechanical systems technology, and several important questions have been explored. However, a unified, easy-to-use methodology to measure the growth rate of individual adherent cells of various sizes has been lacking. Here we demonstrate that a newly developed optical interferometric technique, known as spatial light interference microscopy, can measure the cell dry mass of many individual adherent cells in various conditions, over spatial scales from micrometers to millimeters, temporal scales ranging from seconds to days, and cell types ranging from bacteria to mammalian cells. We found evidence of exponential growth in Escherichia coli, which agrees very well with other recent reports. Perhaps most importantly, combining spatial light interference microscopy with fluorescence imaging provides a unique method for studying cell cycle-dependent growth. Thus, by using a fluorescent reporter for the S phase, we measured single cell growth over each phase of the cell cycle in human osteosarcoma U2OS cells and found that the G2 phase exhibits the highest growth rate, which is mass-dependent and can be approximated by an exponential.

  2. Optical measurement of cycle-dependent cell growth

    PubMed Central

    Mir, Mustafa; Wang, Zhuo; Shen, Zhen; Bednarz, Michael; Bashir, Rashid; Golding, Ido; Prasanth, Supriya G.; Popescu, Gabriel

    2011-01-01

    Determining the growth patterns of single cells offers answers to some of the most elusive questions in contemporary cell biology: how cell growth is regulated and how cell size distributions are maintained. For example, a linear growth in time implies that there is no regulation required to maintain homeostasis; an exponential pattern indicates the opposite. Recently, there has been great effort to measure single cells using microelectromechanical systems technology, and several important questions have been explored. However, a unified, easy-to-use methodology to measure the growth rate of individual adherent cells of various sizes has been lacking. Here we demonstrate that a newly developed optical interferometric technique, known as spatial light interference microscopy, can measure the cell dry mass of many individual adherent cells in various conditions, over spatial scales from micrometers to millimeters, temporal scales ranging from seconds to days, and cell types ranging from bacteria to mammalian cells. We found evidence of exponential growth in Escherichia coli, which agrees very well with other recent reports. Perhaps most importantly, combining spatial light interference microscopy with fluorescence imaging provides a unique method for studying cell cycle-dependent growth. Thus, by using a fluorescent reporter for the S phase, we measured single cell growth over each phase of the cell cycle in human osteosarcoma U2OS cells and found that the G2 phase exhibits the highest growth rate, which is mass-dependent and can be approximated by an exponential. PMID:21788503

  3. Dissection of Ras-Dependent Signaling Pathways Controlling Aggressive Tumor Growth of Human Fibrosarcoma Cells: Evidence for a Potential Novel Pathway

    PubMed Central

    Gupta, Swati; Plattner, Rina; Der, Channing J.; Stanbridge, Eric J.

    2000-01-01

    Activation of multiple signaling pathways is required to trigger the full spectrum of in vitro and in vivo phenotypic traits associated with neoplastic transformation by oncogenic Ras. To determine which of these pathways are important for N-ras tumorigenesis in human cancer cells and also to investigate the possibility of cross talk among the pathways, we have utilized a human fibrosarcoma cell line (HT1080), which contains an endogenous mutated allele of the N-ras gene, and its derivative (MCH603c8), which lacks the mutant N-ras allele. We have stably transfected MCH603c8 and HT1080 cells with activating or dominant-negative mutant cDNAs, respectively, of various components of the Raf, Rac, and RhoA pathways. In previous studies with these cell lines we showed that loss of mutant Ras function results in dramatic changes in the in vitro phenotypic traits and conversion to a weakly tumorigenic phenotype in vivo. We report here that only overexpression of activated MEK contributed significantly to the conversion of MCH603c8 cells to an aggressive tumorigenic phenotype. Furthermore, we have demonstrated that blocking the constitutive activation of the Raf-MEK, Rac, or RhoA pathway alone is not sufficient to block the aggressive tumorigenic phenotype of HT1080, despite affecting a number of in vitro-transformed phenotypic traits. We have also demonstrated the possibility of bidirectional cross talk between the Raf-MEK-ERK pathway and the Rac-JNK or RhoA pathway. Finally, overexpression of activated MEK in MCH603c8 cells appears to result in the activation of an as-yet-unidentified target(s) that is critical for the aggressive tumorigenic phenotype. PMID:11094080

  4. Optimal control on bladder cancer growth model with BCG immunotherapy and chemotherapy

    NASA Astrophysics Data System (ADS)

    Dewi, C.; Trisilowati

    2015-03-01

    In this paper, an optimal control model of the growth of bladder cancer with BCG (Basil Calmate Guerin) immunotherapy and chemotherapy is discussed. The purpose of this optimal control is to determine the number of BCG vaccine and drug should be given during treatment such that the growth of bladder cancer cells can be suppressed. Optimal control is obtained by applying Pontryagin principle. Furthermore, the optimal control problem is solved numerically using Forward-Backward Sweep method. Numerical simulations show the effectiveness of the vaccine and drug in controlling the growth of cancer cells. Hence, it can reduce the number of cancer cells that is not infected with BCG as well as minimize the cost of the treatment.

  5. Growth of cells superinoculated onto irradiated and nonirradiated confluent monolayers

    SciTech Connect

    Matsuoka, H.; Ueo, H.; Sugimachi, K. )

    1990-01-01

    We prepared confluent monolayers of normal BALB/c 3T3 cells and compared differences in the growth of four types of cells superinoculated onto these nonirradiated and irradiated monolayers. The test cells were normal BALB/c 3T3 A31 cells, a squamous cell carcinoma from a human esophageal cancer (KSE-1), human fetal fibroblasts, and V-79 cells from Chinese hamster lung fibroblasts. Cell growth was checked by counting the cell number, determining (3H)thymidine incorporation and assessing colony formation. We found that on nonirradiated monolayers, colony formation of human fetal fibroblasts and normal BALB/c 3T3 cells was completely inhibited. On irradiated cells, test cells did exhibit some growth. KSE-1 cells, which had a low clonogenic efficiency on plastic surfaces, formed colonies on both irradiated and nonirradiated cells. On these monolayers, the clonogenic efficiency of V-79 cells was also higher than that on plastic surfaces. We conclude that the nonirradiated monolayer of BALB/c 3T3 cells completely inhibits the growth of superinoculated normal BALB/c 3T3 and human fetal fibroblasts, while on the other hand, they facilitate the growth of neoplastic KSE-1 and V-79 cells by providing a surface for cell adherence and growth, without affecting the presence of normal cells in co-cultures.

  6. BMP signaling regulates satellite cell-dependent postnatal muscle growth.

    PubMed

    Stantzou, Amalia; Schirwis, Elija; Swist, Sandra; Alonso-Martin, Sonia; Polydorou, Ioanna; Zarrouki, Faouzi; Mouisel, Etienne; Beley, Cyriaque; Julien, Anaïs; Le Grand, Fabien; Garcia, Luis; Colnot, Céline; Birchmeier, Carmen; Braun, Thomas; Schuelke, Markus; Relaix, Frédéric; Amthor, Helge

    2017-08-01

    Postnatal growth of skeletal muscle largely depends on the expansion and differentiation of resident stem cells, the so-called satellite cells. Here, we demonstrate that postnatal satellite cells express components of the bone morphogenetic protein (BMP) signaling machinery. Overexpression of noggin in postnatal mice (to antagonize BMP ligands), satellite cell-specific knockout of Alk3 (the gene encoding the BMP transmembrane receptor) or overexpression of inhibitory SMAD6 decreased satellite cell proliferation and accretion during myofiber growth, and ultimately retarded muscle growth. Moreover, reduced BMP signaling diminished the adult satellite cell pool. Abrogation of BMP signaling in satellite cell-derived primary myoblasts strongly diminished cell proliferation and upregulated the expression of cell cycle inhibitors p21 and p57 In conclusion, these results show that BMP signaling defines postnatal muscle development by regulating satellite cell-dependent myofiber growth and the generation of the adult muscle stem cell pool. © 2017. Published by The Company of Biologists Ltd.

  7. Post-transcriptional control of Amblyomin-X on secretion of vascular endothelial growth factor and expression of adhesion molecules in endothelial cells.

    PubMed

    Drewes, C C; Dias, R Y; Branco, V G; Cavalcante, M F; Souza, J G; Abdalla, D S P; Chudzinski-Tavassi, A M; Farsky, S H P

    2015-07-01

    Angiogenesis is a pivotal process of homeostasis and tissue repair, but it also favours neovascularisation syndromes and cancer nutrition. The chemical mediation of angiogenesis is complex, involving a balance between serine proteases and their inhibitors. We addressed the mechanisms of action of a Kunitz serine protease inhibitor (KPI) on spontaneous angiogenesis, using Amblyomin-X, a KPI designed from the cDNA library of the Amblyomma cajennense tick. Amblyomin-X treatment (10-1000 ng/10 μL; each 48 h; 3 times) reduced the number of vessels in the subcutaneous dorsal tissue of male Swiss mice, as measured by intravital microscopy, haematoxylin-eosin staining, and PECAM-1 immunofluorescence labeling. Incubation of Amblyomin-X with t-End endothelial cells, a murine endothelial microvascular lineage, did not alter cell proliferation, cell-cycle phases, necrosis and apoptosis, and the production of nitric oxide and prostaglandin E2. Nevertheless, Amblyomin-X treatment reduced t-End migration and adhesion to Matrigel(®), and inhibited the VEGF-A secretion and VCAM-1 and β3 integrin expressions by posttranscriptional pathways. Together, data herein outline novel posttranscriptional mechanisms of KPIs on endothelial cells during angiogenesis and point out the possible application of Amblyomin-X as a local inhibitor to undesired neovascularisation process.

  8. Lovastatin inhibited the growth of gastric cancer cells.

    PubMed

    Cheng-Qian, Yang; Xin-Jing, Wei; Wei-Xinbing; Zhuang-Lei, Gao; Hong-Peng, Zhao; Songde, Xu; Pei-Lin, Wang

    2014-01-01

    Gastric cancer cells required large amount of cholesterol to grow and proliferate. The objective of this study was to examine whether the growth of gastric cancer cells was inhibited in vivo by using lovastatin, an effective cholesterol-lowing drug. The mice models for gastric cancer cells MKN45 were divided into two groups, the control and experimental group. Lovastatin was administered orally to the experimental group, while saline given to the control group. We measured the volume and weight of tumors, and calculated RTV (relative tumor volume), T/C (relative added value of tumor) and the inhibition rate. Then the expression levels of PCNA in gastric cancer tissues were examined immunohistochemically. The volume of tumors in the control and experimental groups was 3.801 +/- 1.078 and 3.325 +/- 0.745, respectively (p > 0.05), while RTV was 49.684 +/- 12.250 and 42.506 +/- 10.515, respectively (p > 0.05). T/C, an indication of antitumor, was 85.55%. The weight of tumors of the mice in control and experimental group was 3.23 +/- 0.43 and 2.65 +/- 0.58, respectively (p < 0.05). The inhibition rate was 20.48%. The PCNA index in the lovastatin group was 32.35 +/- 6.43%, while in the control group was 91.24 +/- 6.59%. The PCNA index of lovastatin group was much lower (P < 0.01). Lovastatin inhibited the growth of gastric cancer cells.

  9. [Grape seed extract inhibits the growth of prostate cancer PC-3 cells].

    PubMed

    Huang, Ting-Ting; Shang, Xue-Jun; Yao, Gen-Hong; Ge, Jing-Ping; Teng, Wen-Hui; Sun, Yi; Huang, Yu-Feng

    2008-04-01

    To investigate the inhibitory effect of grape seed extract (GSE) on the growth of prostate cancer PC-3 cells. PC-3 cells were treated with GSE at the concentration of 100, 200 and 300 microg/ml for 24, 48 and 72 hours, respectively. The the inhibitory effect of GSE on the growth of the PC-3 cells and the kidney cells of SD rats was determined by MTT reduction assay, with primarily cultured kidney cells of 1-3 days old SD rats as the normal control. GSE significantly inhibited the growth of PC-3 cells in a concentration- and time-dependent manner, but had only a mild inhibitory effect on the kidney cells. GSE inhibits the growth of prostate cancer PC-3 cells and can be used as a new drug for the treatment of prostate cancer.

  10. IL-6 promotes growth and epithelial-mesenchymal transition of CD133+ cells of non-small cell lung cancer.

    PubMed

    Lee, Soo Ok; Yang, Xiaodong; Duan, Shanzhou; Tsai, Ying; Strojny, Laura R; Keng, Peter; Chen, Yuhchyau

    2016-02-09

    We examined IL-6 effects on growth, epithelial-mesenchymal transition (EMT) process, and metastatic ability of CD133+ and CD133- cell subpopulations isolated from three non-small cell lung cancer (NSCLC) cell lines: A549, H157, and H1299. We developed IL-6 knocked-down and scramble (sc) control cells of A549 and H157 cell lines by lentiviral infection system, isolated CD133+ and CD133- sub-populations, and investigated the IL-6 role in self-renewal/growth of these cells. IL-6 showed either an inhibitory or lack of effect in modulating growth of CD133- cells depending on intracellular IL-6 levels, but there was higher self-renewal ability of IL-6 expressing CD133+ cells than IL-6 knocked down cells, confirming the promoter role of IL-6 in CD133+ cells growth. We then examined tumor growth of xenografts developed from CD133+ cells of A549IL-6si vs. A549sc cell lines. Consistently, there was retarded growth of tumors developed from A549IL-6si, CD133+ cells compared to tumors originating from A549sc, CD133+ cells. The effect of IL-6 in promoting CD133+ self-renewal was due to hedgehog (Hhg) and Erk signaling pathway activation and higher Bcl-2/Bcl-xL expression. We also investigated whether IL-6 regulates the EMT process of CD133- and CD133+ cells differently. Expression of the EMT/metastasis-associated molecules in IL-6 expressing cells was higher than in IL-6 knocked down cells. Together, we demonstrated dual roles of IL-6 in regulating growth of CD133- and CD133+ subpopulations of lung cancer cells and significant regulation of IL-6 on EMT/metastasis increase in CD133+ cells, not in CD133- cells.

  11. Spontaneous Calcium Oscillations Regulate Human Cardiac Progenitor Cell Growth

    PubMed Central

    Ferreira-Martins, João; Rondon-Clavo, Carlos; Tugal, Derin; Korn, Justin A; Rizzi, Roberto; Padin-Iruegas, Maria Elena; Ottolenghi, Sergio; De Angelis, Antonella; Urbanek, Konrad; Iwata, Noriko; D’Amario, Domenico; Hosoda, Toru; Leri, Annarosa; Kajstura, Jan; Anversa, Piero; Rota, Marcello

    2009-01-01

    Rationale The adult heart possesses a pool of progenitor cells stored in myocardial niches but the mechanisms involved in the activation of this cell compartment are currently unknown. Objective Ca2+ promotes cell growth raising the possibility that changes in intracellular Ca2+ initiate division of c-kit-positive human cardiac progenitor cells (hCPCs) and determine their fate. Methods and Results Ca2+ oscillations were identified in hCPCs and these events occurred independently from coupling with cardiomyocytes or the presence of extracellular Ca2+. These findings were confirmed in the heart of transgenic mice in which EGFP was under the control of the c-kit-promoter. Ca2+ oscillations in hCPCs were regulated by the release of Ca2+ from the ER through activation of inositol 1,4,5-triphosphate receptors (IP3Rs) and the re-uptake of Ca2+ by the sarco/endoplasmic reticulum Ca2+ pump (SERCA). IP3Rs and SERCA were highly expressed in hCPCs while ryanodine receptors were not detected. Although Na+-Ca2+ exchanger, store-operated Ca2+-channels and plasma membrane Ca2+-pump were present and functional in hCPCs, they had no direct effects on Ca2+ oscillations. Conversely, Ca2+ oscillations and their frequency markedly increased with ATP and histamine which activated purinoceptors and histamine-1 receptors highly expressed in hCPCs. Importantly, Ca2+ oscillations in hCPCs were coupled with the entry of cells into the cell cycle and BrdUrd incorporation. Induction of Ca2+ oscillations in hCPCs prior to their intramyocardial delivery to infarcted hearts was associated with enhanced engraftment and expansion of these cells promoting the generation of a large myocyte progeny. Conclusion IP3R-mediated Ca2+ mobilization control hCPC growth and their regenerative potential. PMID:19745162

  12. Methyl-donor nutrients inhibit breast cancer cell growth.

    PubMed

    Park, Chung S; Cho, Kyongshin; Bae, Dong R; Joo, Nam E; Kim, Hyung H; Mabasa, Lawrence; Fowler, Andrea W

    2008-01-01

    Lipotropes (methyl group containing nutrients, including methionine, choline, folate, and vitamin B(12)) are dietary methyl donors and cofactors that are involved in one-carbon metabolism, which is important for genomic DNA methylation reactions and nucleic acid synthesis. One-carbon metabolism provides methyl groups for all biological methylation pathways and is highly dependent on dietary supplementation of methyl nutrients. Nutrition is an important determinant of breast cancer risk and tumor behavior, and dietary intervention may be an effective approach to prevent breast cancer. Apoptosis is important for the regulation of homeostasis and tumorigenesis. The anti-apoptotic protein Bcl-2 may be a regulatory target in cancer therapy; controlling or modulating its expression may be a therapeutic strategy against breast cancer. In this study, the effects of lipotrope supplementation on the growth and death of human breast cancer cell lines T47D and MCF-7 were examined and found to inhibit growth of both T47D and MCF-7 cells. Furthermore, the ratios of apoptotic cells to the total number of cells were approximately 44% and 34% higher in the lipotrope-supplemented treatments of T47D and MCF-7 cancer cells, respectively, compared with the control treatments. More importantly, Bcl-2 protein expression was decreased by approximately 25% from lipotrope supplementation in T47D cells, suggesting that lipotropes can induce breast cancer cell death by direct downregulation of Bcl-2 protein expression. Cancer treatment failure is often correlated with Bcl-2 protein upregulation. These data may be useful in the development of effective nutritional strategies to prevent and reduce breast cancer in humans.

  13. [Interference of phytohormones and synthetic growth regulator melafen in the control of Ca2+ translocation across the plasma membrane of potato (Solanum tuberosum L) tuber cells].

    PubMed

    Ladyzhenskaia, E P; Korableva, N P

    2010-01-01

    Interference of phytohormones (jasmonic, gibberellic, and abscisic acids) and synthetic growth regulator melafen on Ca2+ translocation across the membrane of plasma membrane vesicles prepared from dormant potato (Solanum tuberosum L.) tubers was studied. The activity of plasma membrane Ca2+, Mg(2+)-ATPase was stimulated by melafen and jasmonic and gibberellic acids and suppressed by abscisic acid. These agents did not change the passive membrane permeability for Ca2+. The pattern of the effect of melafen on the activity of Ca2+, Mg(2+)-ATPase depended on the presence of phytohormones in incubation medium. When melafen and each phytohormone were simultaneously added to incubation medium, their effects were not additive, which indicates that the effects of the tested compounds on the Ca2+ uptake into the plasma membrane vesicles are interdependent. Apparently, the interaction between the phytohormones and plasma membrane components modulates the response to melafen.

  14. Identification of new cell size control genes in S. cerevisiae

    PubMed Central

    2012-01-01

    Cell size homeostasis is a conserved attribute in many eukaryotic species involving a tight regulation between the processes of growth and proliferation. In budding yeast S. cerevisiae, growth to a “critical cell size” must be achieved before a cell can progress past START and commit to cell division. Numerous studies have shown that progression past START is actively regulated by cell size control genes, many of which have implications in cell cycle control and cancer. Two initial screens identified genes that strongly modulate cell size in yeast. Since a second generation yeast gene knockout collection has been generated, we screened an additional 779 yeast knockouts containing 435 new ORFs (~7% of the yeast genome) to supplement previous cell size screens. Upon completion, 10 new strong size mutants were identified: nine in log-phase cells and one in saturation-phase cells, and 97% of the yeast genome has now been screened for cell size mutations. The majority of the logarithmic phase size mutants have functions associated with translation further implicating the central role of growth control in the cell division process. Genetic analyses suggest ECM9 is directly associated with the START transition. Further, the small (whi) mutants mrpl49Δ and cbs1Δ are dependent on CLN3 for cell size effects. In depth analyses of new size mutants may facilitate a better understanding of the processes that govern cell size homeostasis. PMID:23234503

  15. Hyperbaric oxygen promotes malignant glioma cell growth and inhibits cell apoptosis

    PubMed Central

    WANG, YONG-GANG; ZHAN, YI-PING; PAN, SHU-YI; WANG, HAI-DONG; ZHANG, DUN-XIAO; GAO, KAI; QI, XUE-LING; YU, CHUN-JIANG

    2015-01-01

    Glioblastoma multiforme (GBM) is the most frequently diagnosed intracranial malignant tumor in adults. Clinical studies have indicated that hyperbaric oxygen may improve the prognosis and reduce complications in glioma patients; however, the specific mechanism by which this occurs remains unknown. The present study investigated the direct effects of hyperbaric oxygen stimulation on glioma by constructing an intracranial transplanted glioma model in congenic C57BL/6J mice. Bioluminescent imaging (BLI) was used to assess the growth of intracranial transplanted GL261-Luc glioma cells in vivo, while flow cytometric and immunohistochemical assays were used to detect and compare the expression of the biomarkers, Ki-67, CD34 and TUNEL, reflecting the cell cycle, apoptosis and angiogenesis. BLI demonstrated that hyperbaric oxygen promoted the growth of intracranially transplanted GL261-Luc glioma cells in vivo. Flow cytometric analysis indicated that hyperbaric oxygen promoted GL261-Luc glioma cell proliferation and also prevented cell cycle arrest. In addition, hyperbaric oxygen inhibited the apoptosis of the transplanted glioma cells. Immunohistochemical analysis also indicated that hyperbaric oxygen increased positive staining for Ki-67 and CD34, while reducing staining for TUNEL (a marker of apoptosis). The microvessel density was significantly increased in the hyperbaric oxygen treatment group compared with the control group. In conclusion, hyperbaric oxygen treatment promoted the growth of transplanted malignant glioma cells in vivo and also inhibited the apoptosis of these cells. PMID:26170997

  16. Hyperbaric oxygen promotes malignant glioma cell growth and inhibits cell apoptosis.

    PubMed

    Wang, Yong-Gang; Zhan, Yi-Ping; Pan, Shu-Yi; Wang, Hai-Dong; Zhang, Dun-Xiao; Gao, Kai; Qi, Xue-Ling; Yu, Chun-Jiang

    2015-07-01

    Glioblastoma multiforme (GBM) is the most frequently diagnosed intracranial malignant tumor in adults. Clinical studies have indicated that hyperbaric oxygen may improve the prognosis and reduce complications in glioma patients; however, the specific mechanism by which this occurs remains unknown. The present study investigated the direct effects of hyperbaric oxygen stimulation on glioma by constructing an intracranial transplanted glioma model in congenic C57BL/6J mice. Bioluminescent imaging (BLI) was used to assess the growth of intracranial transplanted GL261-Luc glioma cells in vivo, while flow cytometric and immunohistochemical assays were used to detect and compare the expression of the biomarkers, Ki-67, CD34 and TUNEL, reflecting the cell cycle, apoptosis and angiogenesis. BLI demonstrated that hyperbaric oxygen promoted the growth of intracranially transplanted GL261-Luc glioma cells in vivo. Flow cytometric analysis indicated that hyperbaric oxygen promoted GL261-Luc glioma cell proliferation and also prevented cell cycle arrest. In addition, hyperbaric oxygen inhibited the apoptosis of the transplanted glioma cells. Immunohistochemical analysis also indicated that hyperbaric oxygen increased positive staining for Ki-67 and CD34, while reducing staining for TUNEL (a marker of apoptosis). The microvessel density was significantly increased in the hyperbaric oxygen treatment group compared with the control group. In conclusion, hyperbaric oxygen treatment promoted the growth of transplanted malignant glioma cells in vivo and also inhibited the apoptosis of these cells.

  17. Controlled growth of CH3NH3PbI3 films towards efficient perovskite solar cells by varied-stoichiometric intermediate adduct

    NASA Astrophysics Data System (ADS)

    Tu, Yongguang; Wu, Jihuai; He, Xin; Guo, Panfeng; Luo, Hui; Liu, Quanzhen; Lin, Jianming; Huang, Miaoliang; Huang, Yunfang; Fan, Leqing; Lan, Zhang

    2017-05-01

    Lewis acid-base adduct approach with anti-solvent (diethyl ether) has been one of the efficient strategies to prepare high-quality perovskite films for top-performing perovskite solar cells. Conventionally, the molar ratio of CH3NH3I:PbI2:DMSO in the precursor solution is 1:1:1, however, DMSO will be volatile alongside the extraction of DMF due to its miscibility with DMF solvent during the process of anti-solvent washing, which introduces a non-stoichiometric intermediate adduct CH3NH3I·PbI2·xDMSO (x < 1). In this work, we increased the DMSO content in the Lewis acid-base adduct approach to enhance the conversion efficiency of perovskite solar cells. More complete intermediate adduct CH3NH3I·PbI2·DMSO and wider window period of washing process ensure high-quality perovskite films and high reproducibility with raised content of DMSO. Furthermore, the devices prepared by the precursor solution of CH3NH3I:PbI2:xDMSO (x = 2.0) exhibit high reproducibility and the best efficiency of perovskite solar cells is 17.84% under one-sun illumination.

  18. Insulin-like growth factor-binding protein-3 inhibits IGF-1-induced proliferation of human hepatocellular carcinoma cells by controlling bFGF and PDGF autocrine/paracrine loops.

    PubMed

    Ma, Yang; Han, Chen-Chen; Li, Yifan; Wang, Yang; Wei, Wei

    2016-09-16

    Basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) produced by hepatocellular carcinoma (HCC) cells are responsible for the growth of HCC cells. Accumulating evidence shows that insulin-like growth factor-binding protein-3 (IGFBP-3) suppresses HCC cell proliferation in both IGF-dependent and independent manners. It's unknown, however, whether treatment with exogenous IGFBP-3 inhibits bFGF and PDGF production in HCC cells. The present study demonstrates that IGFBP-3 suppressed IGF-1-induced bFGF and PDGF expression while it does not affect their expression in the absence of IGF-1. To delineate the underlying mechanism, western-blot and RT-PCR assays confirmed that the transcription factor early growth response protein 1 (EGR1) is involved in IGFBP-3 regulation of bFGF and PDGF. IGFBP-3 inhibition of type 1 insulin-like growth factor receptor (IGF1R), ERK and AKT activation is IGF-1-dependent. Furthermore, transient transfection with constitutively activated AKT or MEK partially blocks the IGFBP-3 inhibition of EGR1, bFGF and PDGF expression. In conclusion, these findings suggest that IGFBP-3 suppresses transcription of EGR1 and its target genes bFGF and PDGF through inhibiting IGF-1-dependent ERK and AKT activation. It demonstrates the importance of IGFBP-3 in the regulation of HCC cell proliferation, suggesting that IGFBP-3 could be a target for the treatment of HCC.

  19. S-Adenosylmethionine in cell growth, apoptosis and liver cancer.

    PubMed

    Lu, Shelly C; Mato, José M

    2008-03-01

    S-Adenosylmethionine (SAMe), the principal biological methyl donor, is synthesized from methionine and ATP in a reaction catalyzed by methionine adenosyltransferase (MAT). In mammals, two genes (MAT1A and MAT2A), encode for two homologous MAT catalytic subunits, while a third gene MAT2beta, encodes for the beta-subunit that regulates MAT2A-encoded isoenzyme. Normal liver expresses MAT1A, whereas extrahepatic tissues express MAT2A. MAT2A and MAT2 beta are induced in human hepatocellular carcinoma (HCC), which facilitate cancer cell growth. Patients with cirrhosis of various etiologies, including alcohol, have decreased hepatic MAT activity and SAMe biosynthesis. Consequences of hepatic SAMe deficiency as illustrated by the Mat1a knock-out mouse model include increased susceptibility to steatosis and oxidative liver injury, spontaneous development of steatohepatitis and HCC. Predisposition to HCC can be partly explained by the effect of SAMe on growth. Thus, SAMe inhibits the mitogenic effect of growth factors such as hepatocyte growth factor and, following partial hepatectomy, a fall in SAMe level is required for the liver to regenerate. During liver regeneration, the fall in hepatic SAMe is transient. If the fall were to persist, it would favor a proliferative phenotype and, ultimately, development of HCC. Not only does SAMe control liver growth, it also regulates apoptosis. Interestingly, SAMe is anti-apoptotic in normal hepatocytes but pro-apoptotic in liver cancer cells. In liver cancer cells but not in normal human hepatocytes, SAMe can selectively induce Bcl-x(S), an alternatively spliced isoform of Bcl-x(L) that promotes apoptosis. This should make SAMe an attractive agent for both chemoprevention and treatment of HCC.

  20. Predictors of Longitudinal Growth in Inhibitory Control in Early Childhood

    ERIC Educational Resources Information Center

    Moilanen, Kristin L.; Shaw, Daniel S.; Dishion, Thomas J.; Gardner, Frances; Wilson, Melvin

    2010-01-01

    In the current study, we examined latent growth in 731 young children's inhibitory control from the ages of two to four years, and whether demographic characteristics or parenting behaviors were related to initial levels and growth in inhibitory control. As part of an ongoing longitudinal evaluation of the family check-up, children's inhibitory…

  1. Cell biology. Metabolic control of cell death.

    PubMed

    Green, Douglas R; Galluzzi, Lorenzo; Kroemer, Guido

    2014-09-19

    Beyond their contribution to basic metabolism, the major cellular organelles, in particular mitochondria, can determine whether cells respond to stress in an adaptive or suicidal manner. Thus, mitochondria can continuously adapt their shape to changing bioenergetic demands as they are subjected to quality control by autophagy, or they can undergo a lethal permeabilization process that initiates apoptosis. Along similar lines, multiple proteins involved in metabolic circuitries, including oxidative phosphorylation and transport of metabolites across membranes, may participate in the regulated or catastrophic dismantling of organelles. Many factors that were initially characterized as cell death regulators are now known to physically or functionally interact with metabolic enzymes. Thus, several metabolic cues regulate the propensity of cells to activate self-destructive programs, in part by acting on nutrient sensors. This suggests the existence of "metabolic checkpoints" that dictate cell fate in response to metabolic fluctuations. Here, we discuss recent insights into the intersection between metabolism and cell death regulation that have major implications for the comprehension and manipulation of unwarranted cell loss.

  2. Controls of Fluid Chemistry on Fracture Growth

    SciTech Connect

    Bruton, C; Knauss, K; Viani, B; Bonner, B

    2007-02-26

    During this two year project (the original proposal requested 3 years funding) we developed and tested a new design for a mini-bending jig for the hydrothermal atomic force microscope (HAFM) and a modified design for the HAFM itself. These new capabilities now permit study of the connection between stress and mineral dissolution and growth, as well as sub-critical crack growth (SCG). We demonstrated the successful design by imaging SCG of glass in situ, in real time in the HAFM, as a function of changing solution pH. We generated a movie of the SCG process. We successfully accomplished our project objectives through year 2.

  3. Myc and cell cycle control.

    PubMed

    Bretones, Gabriel; Delgado, M Dolores; León, Javier

    2015-05-01

    Soon after the discovery of the Myc gene (c-Myc), it became clear that Myc expression levels tightly correlate to cell proliferation. The entry in cell cycle of quiescent cells upon Myc enforced expression has been described in many models. Also, the downregulation or inactivation of Myc results in the impairment of cell cycle progression. Given the frequent deregulation of Myc oncogene in human cancer it is important to dissect out the mechanisms underlying the role of Myc on cell cycle control. Several parallel mechanisms account for Myc-mediated stimulation of the cell cycle. First, most of the critical positive cell cycle regulators are encoded by genes induced by Myc. These Myc target genes include Cdks, cyclins and E2F transcription factors. Apart from its direct effects on the transcription, Myc is able to hyperactivate cyclin/Cdk complexes through the induction of Cdk activating kinase (CAK) and Cdc25 phosphatases. Moreover, Myc antagonizes the activity of cell cycle inhibitors as p21 and p27 through different mechanisms. Thus, Myc is able to block p21 transcription or to induce Skp2, a protein involved in p27 degradation. Finally, Myc induces DNA replication by binding to replication origins and by upregulating genes encoding proteins required for replication initiation. Myc also regulates genes involved in the mitotic control. A promising approach to treat tumors with deregulated Myc is the synthetic lethality based on the inhibition of Cdks. Thus, the knowledge of the Myc-dependent cell cycle regulatory mechanisms will help to discover new therapeutic approaches directed against malignancies with deregulated Myc. This article is part of a Special Issue entitled: Myc proteins in cell biology and pathology. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Effects of chocolate cyst fluid on endometrioma cell growth in culture.

    PubMed

    Badawy, S Z; Cuenca, V; Kumar, S; Holland, J

    1998-11-01

    To evaluate the effect of chocolate cyst fluid on the proliferation of cultured human endometrioma cells and to assay the concentration of transforming growth factor-B1 in this fluid. Controlled in vitro study. Department of Obstetrics and Gynecology, State University of New York Health Science Center. Five women with ovarian endometriomas. Endometrioma tissue and chocolate fluid from five different patients were entered in this study. Endometrioma cell proliferation in culture with and without chocolate cyst fluid. Chocolate cyst fluid increased the proliferation of endometrioma cells compared with controls. Also, high concentrations of transforming growth factor-B1 were found in cysts' fluid. Chocolate cyst fluid has a growth-enhancing effect on endometrioma cells. One promoting growth factor is transforming growth factor-B1.

  5. THE TOPOGRAPHY OF TIP GROWTH IN A PLANT CELL

    PubMed Central

    Castle, Edward S.

    1958-01-01

    Tips of young Phycomyces sporangiophores were dusted with starch grains, and growth photographically recorded. Rates of longitudinal displacement from the cell tip of individual markers were determined, also corresponding rates of change of cell diameter. From these the magnitude and spatial distribution of "relative elemental growth rates" along both longitudinal and circumferential axes of the cell were obtained. Growth rates in these two directions are functions of distance from the cell apex, and have different spatial distributions. In particular, rates of growth in cell circumference are complexly patterned. Relative elemental growth rates in length and in girth are approximately equal and maximal at the cell's apex, with a value of 2.4 mm. mm.–1 hr.–1. The characteristic shape of the tip is maintained constant in the face of its changing substance and position. This shape reflects a steady state of the cell's constituent growth patterns. At every point the growing membrane simultaneously expands in the two dimensions of its surface. The degree of polarization or directional preference of growth is measured by the ratio of longitudinal to circumferential relative elemental growth rate at any point. The ratio is not constant, but changes with position along the tip. This fact does not support the idea that membrane growth is based upon a quantal "growth event." Possible causal factors in oriented membrane growth are discussed. PMID:13525674

  6. Thoc1 inhibits cell growth via induction of cell cycle arrest and apoptosis in lung cancer cells.

    PubMed

    Wan, Jianmei; Zou, Shitao; Hu, Mengshang; Zhu, Ran; Xu, Jiaying; Jiao, Yang; Fan, Saijun

    2014-06-01

    THO complex 1 (Thoc1) is a human nuclear matrix protein that binds to the retinoblastoma tumor suppressor retinoblastoma protein (pRb). While some studies suggest that Thoc1 has characteristics of a tumor suppressor protein, whether Thoc1 can inhibit lung cancer cell growth is not clear. In the present study, we observed that Thoc1 is lowly expressed in the lung cancer cell lines SPC-A1 and NCI-H1975. Then, we investigated the potential effects of Thoc1 on lung cancer cell proliferation, cell cycle and apoptosis after stable transfection of these lines with a Thoc1 expression vector. We found that overexpression of Thoc1 can inhibit cell proliferation, induce G2/M cell cycle arrest and promote apoptosis. Further investigation indicated that overexpression of Thoc1 is involved in the inhibition of cell cycle-related proteins cyclin A1 and B1 and of pro-apoptotic factors Bax and caspase-3. In vivo experiments showed that tumors overexpressing Thoc1 display a slower growth rate than the control xenografts and show reduced expression of the protein Ki-67, which localized on the nuclear membrane. Taken together, our data show that in lung cancer cells, Thoc1 inhibits cell growth through induction of cell cycle arrest and apoptosis. These results indicate that Thoc1 may be used as a novel therapeutic target for human lung cancer treatment.

  7. Polyamines regulate cell growth and cellular methylglyoxal in high-glucose medium independently of intracellular glutathione.

    PubMed

    Kwak, Min-Kyu; Lee, Mun-Hyoung; Park, Seong-Jun; Shin, Sang-Min; Liu, Rui; Kang, Sa-Ouk

    2016-03-01

    Polyamines can presumably inhibit protein glycation, when associated with the methylglyoxal inevitably produced during glycolysis. Herein, we hypothesized a nonenzymatic interaction between putrescine and methylglyoxal in putrescine-deficient or -overexpressing Dictyostelium cells in high-glucose medium, which can control methylglyoxal production. Putrescine was essentially required for growth rescue accompanying methylglyoxal detoxification when cells underwent growth defect and cell cycle G1-arrest when supplemented with high glucose. Furthermore, methylglyoxal regulation by putrescine seemed to be a parallel pathway independent of the changes in cellular glutathione content in high-glucose medium. Consequently, we suggest that Dictyostelium cells need polyamines for normal growth and cellular methylglyoxal regulation.

  8. Growth of III-V films by control of MBE growth front stoichiometry

    NASA Technical Reports Server (NTRS)

    Grunthaner, Frank J. (Inventor); Liu, John K. (Inventor); Hancock, Bruce R. (Inventor)

    1992-01-01

    For the growth of strain-layer materials and high quality single and multiple quantum wells, the instantaneous control of growth front stoichiometry is critical. The process of the invention adjusts the offset or phase of molecular beam epitaxy (MBE) control shutters to program the instantaneous arrival or flux rate of In and As4 reactants to grow InAs. The interrupted growth of first In, then As4, is also a key feature.

  9. Density-dependent regulation of growth of BSC-1 cells in cell culture: growth inhibitors formed by the cells.

    PubMed Central

    Holley, R W; Armour, R; Baldwin, J H

    1978-01-01

    Inhibitors formed by a monkey epithelial cell line, BSC-1, play an important role in limiting growth at high cell densities. At least three inhibitors are formed: lactic acid, ammonia, and an unidentified inhibitor that may be an unstable protein. The unidentified inhibitor is destroyed by shaking the conditioned medium, by bubbling gas through the medium, or by heating or storing the medium in the absence of cells. The concentrations of lactic acid and ammonia that accumulate in conditioned medium inhibit growth when added to fresh medium. These results, together with earlier studies, indicate that density-dependent regulation of growth of BSC-1 cells results from the combined effects of (a) inhibitors formed by the cells, (b) decreased availability of receptor sites for serum growth factors as the cells become crowded, and (c) limiting concentrations of low molecular weight nutrients in the medium. In contrast, density-dependent regulation of growth in 3T3 mouse embryo fibroblasts results almost entirely from inactivation of serum factors. PMID:273914

  10. Thiazolidinediones enhance vascular endothelial growth factor expression and induce cell growth inhibition in non-small-cell lung cancer cells

    PubMed Central

    2010-01-01

    Background It is known that thiazolidinediones are involved in regulating the expression of various genes, including the vascular endothelial growth factor (VEGF) gene via peroxisome proliferator-activated receptor γ (PPARγ); VEGF is a prognostic biomarker for non-small-cell lung cancer (NSCLC). Methods In this study, we investigated the effects of troglitazone and ciglitazone on the mRNA expression of VEGF and its receptors in human NSCLC cell lines, RERF-LC-AI, SK-MES-1, PC-14, and A549. These mRNA expressions were evaluated by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis. We also studied the effect of Je-11, a VEGF inhibitor, on the growth of these cells. Results In NSCLC cells, thiazolidinediones increased the mRNA expression of VEGF and neuropilin-1, but not that of other receptors such as fms-like tyrosine kinase and kinase insert domain receptor-1. Furthermore, the PPARγ antagonist GW9662 completely reversed this thiazolidinedione-induced increase in VEGF expression. Furthermore, the addition of VEGF inhibitors into the culture medium resulted in the reversal of thiazolidinedione-induced growth inhibition. Conclusions Our results indicated that thiazolidinediones enhance VEGF and neuropilin-1 expression and induce the inhibition of cell growth. We propose the existence of a pathway for arresting cell growth that involves the interaction of thiazolidinedione-induced VEGF and neuropilin-1 in NSCLC. PMID:20214829

  11. Stromal interaction molecule 1 regulates growth, cell cycle, and apoptosis of human tongue squamous carcinoma cells.

    PubMed

    Cui, Xiaobo; Song, Laixiao; Bai, Yunfei; Wang, Yaping; Wang, Boqian; Wang, Wei

    2017-04-30

    Oral tongue squamous cell carcinoma (OTSCC) is the most common type of oral carcinomas. However, the molecular mechanism by which OTSCC developed is not fully identified. Stromal interaction molecule 1 (STIM1) is a transmembrane protein, mainly located in the endoplasmic reticulum (ER). STIM1 is involved in several types of cancers. Here, we report that STIM1 contributes to the development of human OTSCC. We knocked down STIM1 in OTSCC cell line Tca-8113 with lentivirus-mediated shRNA and found that STIM1 knockdown repressed the proliferation of Tca-8113 cells. In addition, we also showed that STIM1 deficiency reduced colony number of Tca-8113 cells. Knockdown of STIM1 repressed cells to enter M phase of cell cycle and induced cellular apoptosis. Furthermore, we performed microarray and bioinformatics analysis and found that STIM1 was associated with p53 and MAPK pathways, which may contribute to the effects of STIM1 on cell growth, cell cycle, and apoptosis. Finally, we confirmed that STIM1 controlled the expression of MDM2, cyclin-dependent kinase 4 (CDK4), and growth arrest and DNA damage inducible α (GADD45A) in OTSCC cells. In conclusion, we provide evidence that STIM1 contributes to the development of OTSCC partially through regulating p53 and MAPK pathways to promote cell cycle and survival.

  12. Alginate as a cell culture substrate for growth and differentiation of human retinal pigment epithelial cells.

    PubMed

    Heidari, Razeih; Soheili, Zahra-Soheila; Samiei, Shahram; Ahmadieh, Hamid; Davari, Maliheh; Nazemroaya, Fatemeh; Bagheri, Abouzar; Deezagi, Abdolkhalegh

    2015-03-01

    The purpose of this study was to evaluate retinal pigment epithelium (RPE) cells' behavior in alginate beads that establish 3D environment for cellular growth and mimic extracellular matrix versus the conventional 2D monolayer culture. RPE cells were encapsulated in alginate beads by dripping alginate cell suspension into CaCl2 solution. Beads were suspended in three different media including Dulbecco's modified Eagle's medium (DMEM)/F12 alone, DMEM/F12 supplemented with 10 % fetal bovine serum (FBS), and DMEM/F12 supplemented with 30 % human amniotic fluid (HAF). RPE cells were cultivated on polystyrene under the same conditions as controls. Cell phenotype, cell proliferation, cell death, and MTT assay, immunocytochemistry, and real-time RT-PCR were performed to evaluate the effect of alginate on RPE cells characteristics and integrity. RPE cells can survive and proliferate in alginate matrixes. Immunocytochemistry analysis exhibited Nestin, RPE65, and cytokeratin expressions in a reasonable number of cultured cells in alginate beads. Real-time PCR data demonstrated high levels of Nestin, CHX10, RPE65, and tyrosinase gene expressions in RPE cells immobilized in alginate when compared to 2D monolayer culture systems. The results suggest that alginate can be used as a reliable scaffold for maintenance of RPE cells' integrity and in vitro propagation of human retinal progenitor cells for cell replacement therapies in retinal diseases.

  13. Growth control by a moving morphogen gradient during Drosophila eye development.

    PubMed

    Wartlick, Ortrud; Jülicher, Frank; Gonzalez-Gaitan, Marcos

    2014-05-01

    During morphogenesis, organs grow to stereotyped sizes, but growth control mechanisms are poorly understood. Here, we measured the signaling dynamics of the morphogen Dpp, one of several Drosophila factors controlling morphogenetic growth, in the developing eye. In this tissue, the Dpp expression domain advances from the posterior to the anterior tissue edge. In front of this moving morphogen source, signaling inputs including Dpp activate the target gene hairy in a gradient that scales with tissue size. Proliferation, in turn, occurs in a mitotic wave in front of the source, whereas behind it, cells arrest and differentiate. We found that cells divide when their signaling levels have increased by around 60%. This simple mechanism quantitatively explains the proliferation and differentiation waves in wild type and mutants. Furthermore, this mechanism may be a common feature of different growth factors, because a Dpp-independent growth input also follows this growth rule.

  14. Controlling condensation and frost growth with chemical micropatterns

    SciTech Connect

    Boreyko, Jonathan B.; Hansen, Ryan R.; Murphy, Kevin R.; Nath, Saurabh; Retterer, Scott T.; Collier, C. Patrick

    2016-01-22

    Frost growth on chilled hydrophobic surfaces is an inter-droplet phenomenon, where frozen droplets harvest water from supercooled liquid droplets to grow ice bridges that propagate across the surface in a chain reaction. To date, no surface has been able to passively prevent the in-plane growth of frost across the population of supercooled condensate. Here, we demonstrate that when the nucleation sites for supercooled condensate are properly controlled with chemical micropatterns, the speed of frost growth can be slowed and even halted entirely. This stoppage of frost growth is attributed to the large interdroplet separation between condensate upon the onset of freezing, which was controlled by the pitch of the chemical patterns and by deliberately triggering an early freezing event. Lastly, these findings reveal that frost growth can be passively suppressed by designing surfaces to spatially control nucleation sites and/or temporally control the onset of freezing events.

  15. Controlling condensation and frost growth with chemical micropatterns

    DOE PAGES

    Boreyko, Jonathan B.; Hansen, Ryan R.; Murphy, Kevin R.; ...

    2016-01-22

    Frost growth on chilled hydrophobic surfaces is an inter-droplet phenomenon, where frozen droplets harvest water from supercooled liquid droplets to grow ice bridges that propagate across the surface in a chain reaction. To date, no surface has been able to passively prevent the in-plane growth of frost across the population of supercooled condensate. Here, we demonstrate that when the nucleation sites for supercooled condensate are properly controlled with chemical micropatterns, the speed of frost growth can be slowed and even halted entirely. This stoppage of frost growth is attributed to the large interdroplet separation between condensate upon the onset ofmore » freezing, which was controlled by the pitch of the chemical patterns and by deliberately triggering an early freezing event. Lastly, these findings reveal that frost growth can be passively suppressed by designing surfaces to spatially control nucleation sites and/or temporally control the onset of freezing events.« less