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Sample records for cgamma1 pathway regulates

  1. Overactivation of phospholipase C-gamma1 renders platelet-derived growth factor beta-receptor-expressing cells independent of the phosphatidylinositol 3-kinase pathway for chemotaxis

    DEFF Research Database (Denmark)

    Rönnstrand, L; Siegbahn, A; Rorsman, C;

    1999-01-01

    ., Siegbahn, A. , Rorsman, C., Engström, U., Wernstedt, C., Heldin, C.-H., and Rönnstrand, L. (1996) EMBO J. 15, 5299-5313). Here we show that the increased chemotaxis correlates with increased activation of phospholipase C-gamma1 (PLC-gamma1), measured as inositol-1,4, 5-trisphosphate release. By two......-dimensional phosphopeptide mapping, the increase in phosphorylation of PLC-gamma1 was shown not to be selective for any site, rather a general increase in phosphorylation of PLC-gamma1 was seen. Specific inhibitors of protein kinase C, bisindolylmaleimide (GF109203X), and phosphatidylinositol 3-kinase (PI3-kinase), LY294002......, did not affect the activation of PLC-gamma1. To assess whether increased activation of PLC-gamma1 is the cause of the hyperchemotactic behavior of the Y934F mutant cell line, we constructed cell lines expressing either wild-type or a catalytically compromised version of PLC-gamma1 under a tetracycline...

  2. Activation of H2O2-induced VSOR Cl- currents in HTC cells require phospholipase Cgamma1 phosphorylation and Ca2+ mobilisation

    DEFF Research Database (Denmark)

    Varela, Diego; Simon, Felipe; Olivero, Pablo

    2007-01-01

    Volume-sensitive outwardly rectifying (VSOR) Cl(-) channels participate in several physiological processes such as regulatory volume decrease, cell cycle regulation, proliferation and apoptosis. Recent evidence points to a significant role of hydrogen peroxide (H(2)O(2)) in VSOR Cl(-) channel...... activation. The aim of this study was to determine the signalling pathways responsible for H(2)O(2)-induced VSOR Cl(-) channel activation. In rat hepatoma (HTC) cells, H(2)O(2) elicited a transient increase in tyrosine phosphorylation of phospholipase Cgamma1 (PLCgamma1) that was blocked by PP2, a Src......)R) blocker 2-APB. In line with these results, manoeuvres that prevented PLCgamma1 activation and/or [Ca(2+)](i) rise, abolished H(2)O(2)-induced VSOR Cl(-) currents. Furthermore, in cells that overexpress a phosphorylation-defective dominant mutant of PLCgamma1, H(2)O(2) did not induce activation...

  3. Mutation of the phospholipase C-gamma1-binding site of LAT affects both positive and negative thymocyte selection.

    Science.gov (United States)

    Sommers, Connie L; Lee, Jan; Steiner, Kevin L; Gurson, Jordan M; Depersis, Corinne L; El-Khoury, Dalal; Fuller, Claudette L; Shores, Elizabeth W; Love, Paul E; Samelson, Lawrence E

    2005-04-01

    Linker for activation of T cells (LAT) is a scaffolding adaptor protein that is critical for T cell development and function. A mutation of LAT (Y136F) that disrupts phospholipase C-gamma1 activation and subsequent calcium influx causes a partial block in T cell development and leads to a severe lymphoproliferative disease in homozygous knock-in mice. One possible contribution to the fatal disease of LAT Y136F knock-in mice could be from autoreactive T cells generated in these mice because of altered thymocyte selection. To examine the impact of the LAT Y136F mutation on thymocyte positive and negative selection, we bred this mutation onto the HY T cell receptor (TCR) transgenic, recombination activating gene-2 knockout background. Female mice with this genotype showed a severe defect in positive selection, whereas male mice exhibited a phenotype resembling positive selection (i.e., development and survival of CD8(hi) HY TCR-specific T cells) instead of negative selection. These results support the hypothesis that in non-TCR transgenic, LAT Y136F knock-in mice, altered thymocyte selection leads to the survival and proliferation of autoreactive T cells that would otherwise be negatively selected in the thymus.

  4. Novel protein regulates ERK pathway

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ The ERK (extracellular signal-regulated kinase) pathway plays a critical role in the vital processes of living cells such as proliferation and differentiation.Recently, CAS scientists in Shanghai have discovered a novel mechanism of spatial regulation on ERK pathway. The result was published in the 4 September issue of the Proceedings of National Academy of Sciences(PNAS).

  5. Multiple pathways regulate shoot branching

    Directory of Open Access Journals (Sweden)

    Catherine eRameau

    2015-01-01

    Full Text Available Shoot branching patterns result from the spatio-temporal regulation of axillary bud outgrowth. Numerous endogenous, developmental and environmental factors are integrated at the bud and plant levels to determine numbers of growing shoots. Multiple pathways that converge to common integrators are most probably involved. We propose several pathways involving not only the classical hormones auxin, cytokinins and strigolactones, but also other signals with a strong influence on shoot branching such as gibberellins, sugars or molecular actors of plant phase transition. We also deal with recent findings about the molecular mechanisms and the pathway involved in the response to shade as an example of an environmental signal controlling branching. We propose the TCP transcription factor TB1/BRC1 and the polar auxin transport stream in the stem as possible integrators of these pathways. We finally discuss how modeling can help to represent this highly dynamic system by articulating knowledges and hypothesis and calculating the phenotype properties they imply.

  6. Phospholipase C-gamma1 is required for subculture-induced terminal differentiation of normal human oral keratinocytes.

    Science.gov (United States)

    Oh, Ju-Eun; Kook, Joong-Ki; Park, Kyung-Hee; Lee, Gene; Seo, Byoung-Moo; Min, Byung-Moo

    2003-04-01

    Serial subculture of primary normal human oral keratinocytes (NHOKs) to the post-mitotic stage induces terminal differentiation, which is in part linked to elevated levels of phospholipase C (PLC)-gamma1. Therefore, PLC-gamma1 may be involved in the signal transduction system that leads to the calcium regulation of subculture-induced keratinocyte differentiation. To test this hypothesis, the expression of PLC-gamma1 in primary NHOKs was blocked by transfecting cells with the antisense PLC-gamma1 cDNA construct. These cells demonstrated dramatic reductions in PLC-gamma1 protein and in the differentiation markers involucrin and transglutaminase following calcium exposure and an increase (15-20%) in in vitro life span versus empty vector-transfected cells. In addition, we established the ability of antisense PLC-gamma1 to block the serial subculture-induced rise in intracellular calcium. Similar observations were made following treatment with the specific PLC inhibitor U73122. These results indicate that the terminal differentiation of NHOKs by serial subculture is associated with PLC-gamma1, which mediates calcium regulation by mobilizing intracellular calcium.

  7. DMPD: Regulation of mitochondrial antiviral signaling pathways. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18549796 Regulation of mitochondrial antiviral signaling pathways. Moore CB, Ting J...P. Immunity. 2008 Jun;28(6):735-9. (.png) (.svg) (.html) (.csml) Show Regulation of mitochondrial antiviral ...signaling pathways. PubmedID 18549796 Title Regulation of mitochondrial antiviral signaling pathways. Author

  8. [Pathways of flowering regulation in plants].

    Science.gov (United States)

    Liu, Yongping; Yang, Jing; Yang, Mingfeng

    2015-11-01

    Flowering, the floral transition from vegetative growth to reproductive growth, is induced by diverse endogenous and exogenous cues, such as photoperiod, temperature, hormones and age. Precise flowering time is critical to plant growth and evolution of species. The numerous renewal molecular and genetic results have revealed five flowering time pathways, including classical photoperiod pathway, vernalization pathway, autonomous pathway, gibberellins (GA) pathway and newly identified age pathway. These pathways take on relatively independent role, and involve extensive crosstalks and feedback loops. This review describes the complicated regulatory network of this floral transition to understand the molecular mechanism of flowering and provide references for further research in more plants.

  9. Master regulators, regulatory networks, and pathways of glioblastoma subtypes.

    Science.gov (United States)

    Bozdag, Serdar; Li, Aiguo; Baysan, Mehmet; Fine, Howard A

    2014-01-01

    Glioblastoma multiforme (GBM) is the most common malignant brain tumor. GBM samples are classified into subtypes based on their transcriptomic and epigenetic profiles. Despite numerous studies to better characterize GBM biology, a comprehensive study to identify GBM subtype- specific master regulators, gene regulatory networks, and pathways is missing. Here, we used FastMEDUSA to compute master regulators and gene regulatory networks for each GBM subtype. We also ran Gene Set Enrichment Analysis and Ingenuity Pathway Analysis on GBM expression dataset from The Cancer Genome Atlas Project to compute GBM- and GBM subtype-specific pathways. Our analysis was able to recover some of the known master regulators and pathways in GBM as well as some putative novel regulators and pathways, which will aide in our understanding of the unique biology of GBM subtypes.

  10. Signaling pathways regulating murine pancreatic development

    DEFF Research Database (Denmark)

    Serup, Palle

    2012-01-01

    The recent decades have seen a huge expansion in our knowledge about pancreatic development. Numerous lineage-restricted transcription factor genes have been identified and much has been learned about their function. Similarly, numerous signaling pathways important for pancreas development have...

  11. BMP pathway regulation of and by macrophages.

    Directory of Open Access Journals (Sweden)

    Megha Talati

    Full Text Available Pulmonary arterial hypertension (PAH is a disease of progressively increasing pulmonary vascular resistance, associated with mutations of the type 2 receptor for the BMP pathway, BMPR2. The canonical signaling pathway for BMPR2 is through the SMAD family of transcription factors. BMPR2 is expressed in every cell type, but the impact of BMPR2 mutations affecting SMAD signaling, such as Bmpr2delx4+, had only previously been investigated in smooth muscle and endothelium. In the present study, we created a mouse with universal doxycycline-inducible expression of Bmpr2delx4+ in order to determine if broader expression had an impact relevant to the development of PAH. We found that the most obvious phenotype was a dramatic, but patchy, increase in pulmonary inflammation. We crossed these double transgenic mice onto an NF-κB reporter strain, and by luciferase assays on live mice, individual organs and isolated macrophages, we narrowed down the origin of the inflammatory phenotype to constitutive activation of tissue macrophages. Study of bone marrow-derived macrophages from mutant and wild-type mice suggested a baseline difference in differentiation state in Bmpr2 mutants. When activated with LPS, both mutant and wild-type macrophages secrete BMP pathway inhibitors sufficient to suppress BMP pathway activity in smooth muscle cells (SMC treated with conditioned media. Functionally, co-culture with macrophages results in a BMP signaling-dependent increase in scratch closure in cultured SMC. We conclude that SMAD signaling through BMP is responsible, in part, for preventing macrophage activation in both live animals and in cells in culture, and that activated macrophages secrete BMP inhibitors in sufficient quantity to cause paracrine effect on vascular smooth muscle.

  12. The Hippo pathway regulates hematopoiesis in Drosophila melanogaster.

    Science.gov (United States)

    Milton, Claire C; Grusche, Felix A; Degoutin, Joffrey L; Yu, Eefang; Dai, Qi; Lai, Eric C; Harvey, Kieran F

    2014-11-17

    The Salvador-Warts-Hippo (Hippo) pathway is an evolutionarily conserved regulator of organ growth and cell fate. It performs these functions in epithelial and neural tissues of both insects and mammals, as well as in mammalian organs such as the liver and heart. Despite rapid advances in Hippo pathway research, a definitive role for this pathway in hematopoiesis has remained enigmatic. The hematopoietic compartments of Drosophila melanogaster and mammals possess several conserved features. D. melanogaster possess three types of hematopoietic cells that most closely resemble mammalian myeloid cells: plasmatocytes (macrophage-like cells), crystal cells (involved in wound healing), and lamellocytes (which encapsulate parasites). The proteins that control differentiation of these cells also control important blood lineage decisions in mammals. Here, we define the Hippo pathway as a key mediator of hematopoiesis by showing that it controls differentiation and proliferation of the two major types of D. melanogaster blood cells, plasmatocytes and crystal cells. In animals lacking the downstream Hippo pathway kinase Warts, lymph gland cells overproliferated, differentiated prematurely, and often adopted a mixed lineage fate. The Hippo pathway regulated crystal cell numbers by both cell-autonomous and non-cell-autonomous mechanisms. Yorkie and its partner transcription factor Scalloped were found to regulate transcription of the Runx family transcription factor Lozenge, which is a key regulator of crystal cell fate. Further, Yorkie or Scalloped hyperactivation induced ectopic crystal cells in a non-cell-autonomous and Notch-pathway-dependent fashion.

  13. Physiological regulation of NEFA availability: lipolysis pathway.

    Science.gov (United States)

    Stich, V; Berlan, M

    2004-05-01

    Plasma NEFA are an important energy substrate and, furthermore, play a key role in the induction of insulin resistance in the body. The availability of NEFA is determined predominantly by their mobilization from adipose tissue triacylglycerol stores by the process of lipolysis. Adipose tissue lipolysis in man is regulated by a number of hormonal and paracrine and/or autocrine signals. The main hormonal signals may be represented by catecholamines, insulin, growth hormone, natriuretic peptides and some adipocytokines. The absolute levels and relative importance and contribution of these signals vary in different physiological situations, with diet and physical exercise being the main physiological variables that affect the hormonal signalling. Thus, modulations in hormonal signals induce an increase in NEFA mobilization in the post-absorptive state and during an acute bout of exercise, and suppress NEFA mobilization in the postprandial state. In addition, hormonal regulation is modified by long-term interventions in energy balance, such as dietary restriction and/or physical training, and is disturbed in some pathological states, such as obesity or diabetes. The question that remains is whether disturbances in lipolysis regulation in obese and diabetic subjects may be 'corrected' by the long-term interventions in diet and physical activity.

  14. Profiling of molecular pathways regulated by microRNA 601.

    Science.gov (United States)

    Ohdaira, Hiroaki; Nakagawa, Hiroki; Yoshida, Kenichi

    2009-12-01

    MicroRNAs (miRNAs) have been implicated in complex vertebrate developmental and pathological systems as a versatile class of molecules involved in the regulation of various biological processes and molecular pathways. To elucidate the role of miRNAs in human somatic cells, an understanding of the molecular framework regulated by individual miRNA is essential. In this study, we examined the effect of hsa-miR-601 on gene expression changes in human lung cancer cells A549. To achieve this, DNA microarray and global pathway analyses were performed on hsa-miR-601 introduced cells for two successive days. Gene ontology analysis revealed that the effect of hsa-miR-601 over-represented the negative regulation of translation/translational initiation, whereas GenMAPP analysis revealed that several characteristic pathways were changed in hsa-miR-601 introduced A549 cells compared to control short RNA introduced cells. Among them, up-regulation of actin cytoskeleton and down-regulation of Fas-induced apoptosis pathway occurred on two successive days after hsa-miR-601 introduction. Using a luciferase reporter assay, we also showed that hsa-miR-601 specifically repressed nuclear factor-kappaB (NF-kappaB) transcription factor-dependent reporter expression, a key component of the immune-oncogenesis pathway. These findings suggest that hsa-miR-601 could affect a variety of signaling pathways accompanying orchestrated gene expression changes. Our results argue that individual miRNAs affect complex regulation of cellular signaling pathways.

  15. Analyzing the regulation of metabolic pathways in human breast cancer

    Directory of Open Access Journals (Sweden)

    Schramm Gunnar

    2010-09-01

    Full Text Available Abstract Background Tumor therapy mainly attacks the metabolism to interfere the tumor's anabolism and signaling of proliferative second messengers. However, the metabolic demands of different cancers are very heterogeneous and depend on their origin of tissue, age, gender and other clinical parameters. We investigated tumor specific regulation in the metabolism of breast cancer. Methods For this, we mapped gene expression data from microarrays onto the corresponding enzymes and their metabolic reaction network. We used Haar Wavelet transforms on optimally arranged grid representations of metabolic pathways as a pattern recognition method to detect orchestrated regulation of neighboring enzymes in the network. Significant combined expression patterns were used to select metabolic pathways showing shifted regulation of the aggressive tumors. Results Besides up-regulation for energy production and nucleotide anabolism, we found an interesting cellular switch in the interplay of biosynthesis of steroids and bile acids. The biosynthesis of steroids was up-regulated for estrogen synthesis which is needed for proliferative signaling in breast cancer. In turn, the decomposition of steroid precursors was blocked by down-regulation of the bile acid pathway. Conclusion We applied an intelligent pattern recognition method for analyzing the regulation of metabolism and elucidated substantial regulation of human breast cancer at the interplay of cholesterol biosynthesis and bile acid metabolism pointing to specific breast cancer treatment.

  16. DMPD: The negative regulation of Toll-like receptor and associated pathways. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17621314 The negative regulation of Toll-like receptor and associated pathways. Lan...) Show The negative regulation of Toll-like receptor and associated pathways. PubmedID 17621314 Title The ne...gative regulation of Toll-like receptor and associated pathways. Authors Lang T,

  17. The Hippo-Salvador signaling pathway regulates renal tubulointerstitial fibrosis.

    Science.gov (United States)

    Seo, Eunjeong; Kim, Wan-Young; Hur, Jeongmi; Kim, Hanbyul; Nam, Sun Ah; Choi, Arum; Kim, Yu-Mi; Park, Sang Hee; Chung, Chaeuk; Kim, Jin; Min, Soohong; Myung, Seung-Jae; Lim, Dae-Sik; Kim, Yong Kyun

    2016-08-23

    Renal tubulointerstitial fibrosis (TIF) is the final pathway of various renal injuries that result in chronic kidney disease. The mammalian Hippo-Salvador signaling pathway has been implicated in the regulation of cell proliferation, cell death, tissue regeneration, and tumorigenesis. Here, we report that the Hippo-Salvador pathway plays a role in disease development in patients with TIF and in a mouse model of TIF. Mice with tubular epithelial cell (TEC)-specific deletions of Sav1 (Salvador homolog 1) exhibited aggravated renal TIF, enhanced epithelial-mesenchymal transition-like phenotypic changes, apoptosis, and proliferation after unilateral ureteral obstruction (UUO). Moreover, Sav1 depletion in TECs increased transforming growth factor (TGF)-β and activated β-catenin expression after UUO, which likely accounts for the abovementioned enhanced TEC fibrotic phenotype. In addition, TAZ (transcriptional coactivator with PDZ-binding motif), a major downstream effector of the Hippo pathway, was significantly activated in Sav1-knockout mice in vivo. An in vitro study showed that TAZ directly regulates TGF-β and TGF-β receptor II expression. Collectively, our data indicate that the Hippo-Salvador pathway plays a role in the pathogenesis of TIF and that regulating this pathway may be a therapeutic strategy for reducing TIF.

  18. The Hippo-Salvador signaling pathway regulates renal tubulointerstitial fibrosis

    Science.gov (United States)

    Seo, Eunjeong; Kim, Wan-Young; Hur, Jeongmi; Kim, Hanbyul; Nam, Sun Ah; Choi, Arum; Kim, Yu-Mi; Park, Sang Hee; Chung, Chaeuk; Kim, Jin; Min, Soohong; Myung, Seung-Jae; Lim, Dae-Sik; Kim, Yong Kyun

    2016-01-01

    Renal tubulointerstitial fibrosis (TIF) is the final pathway of various renal injuries that result in chronic kidney disease. The mammalian Hippo-Salvador signaling pathway has been implicated in the regulation of cell proliferation, cell death, tissue regeneration, and tumorigenesis. Here, we report that the Hippo-Salvador pathway plays a role in disease development in patients with TIF and in a mouse model of TIF. Mice with tubular epithelial cell (TEC)-specific deletions of Sav1 (Salvador homolog 1) exhibited aggravated renal TIF, enhanced epithelial-mesenchymal transition-like phenotypic changes, apoptosis, and proliferation after unilateral ureteral obstruction (UUO). Moreover, Sav1 depletion in TECs increased transforming growth factor (TGF)-β and activated β-catenin expression after UUO, which likely accounts for the abovementioned enhanced TEC fibrotic phenotype. In addition, TAZ (transcriptional coactivator with PDZ-binding motif), a major downstream effector of the Hippo pathway, was significantly activated in Sav1-knockout mice in vivo. An in vitro study showed that TAZ directly regulates TGF-β and TGF-β receptor II expression. Collectively, our data indicate that the Hippo-Salvador pathway plays a role in the pathogenesis of TIF and that regulating this pathway may be a therapeutic strategy for reducing TIF. PMID:27550469

  19. Signal Transduction Pathways that Regulate CAB Gene Expression

    Energy Technology Data Exchange (ETDEWEB)

    Chory, Joanne

    2006-01-16

    The process of chloroplast differentiation, involves the coordinate regulation of many nuclear and chloroplast genes. The cues for the initiation of this developmental program are both extrinsic (e.g., light) and intrinsic (cell-type and plastid signals). During this project period, we utilized a molecular genetic approach to select for Arabidopsis mutants that did not respond properly to environmental light conditions, as well as mutants that were unable to perceive plastid damage. These latter mutants, called gun mutants, define two retrograde signaling pathways that regulate nuclear gene expression in response to chloroplasts. A major finding was to identify a signal from chloroplasts that regulates nuclear gene transcription. This signal is the build-up of Mg-Protoporphyrin IX, a key intermediate of the chlorophyll biosynthetic pathway. The signaling pathways downstream of this signal are currently being studied. Completion of this project has provided an increased understanding of the input signals and retrograde signaling pathways that control nuclear gene expression in response to the functional state of chloroplasts. These studies should ultimately influence our abilities to manipulate plant growth and development, and will aid in the understanding of the developmental control of photosynthesis.

  20. Signal Transduction Pathways that Regulate CAB Gene Expression

    Energy Technology Data Exchange (ETDEWEB)

    Chory, Joanne

    2004-12-31

    The process of chloroplast differentiation, involves the coordinate regulation of many nuclear and chloroplast genes. The cues for the initiation of this developmental program are both extrinsic (e.g., light) and intrinsic (cell-type and plastid signals). During this project period, we utilized a molecular genetic approach to select for Arabidopsis mutants that did not respond properly to environmental light conditions, as well as mutants that were unable to perceive plastid damage. These latter mutants, called gun mutants, define two retrograde signaling pathways that regulate nuclear gene expression in response to chloroplasts. A major finding was to identify a signal from chloroplasts that regulates nuclear gene transcription. This signal is the build-up of Mg-Protoporphyrin IX, a key intermediate of the chlorophyll biosynthetic pathway. The signaling pathways downstream of this signal are currently being studied. Completion of this project has provided an increased understanding of the input signals and retrograde signaling pathways that control nuclear gene expression in response to the functional state of chloroplasts. These studies should ultimately influence our abilities to manipulate plant growth and development, and will aid in the understanding of the developmental control of photosynthesis.

  1. Estrogen receptors regulate innate immune cells and signaling pathways.

    Science.gov (United States)

    Kovats, Susan

    2015-04-01

    Humans show strong sex differences in immunity to infection and autoimmunity, suggesting sex hormones modulate immune responses. Indeed, receptors for estrogens (ERs) regulate cells and pathways in the innate and adaptive immune system, as well as immune cell development. ERs are ligand-dependent transcription factors that mediate long-range chromatin interactions and form complexes at gene regulatory elements, thus promoting epigenetic changes and transcription. ERs also participate in membrane-initiated steroid signaling to generate rapid responses. Estradiol and ER activity show profound dose- and context-dependent effects on innate immune signaling pathways and myeloid cell development. While estradiol most often promotes the production of type I interferon, innate pathways leading to pro-inflammatory cytokine production may be enhanced or dampened by ER activity. Regulation of innate immune cells and signaling by ERs may contribute to the reported sex differences in innate immune pathways. Here we review the recent literature and highlight several molecular mechanisms by which ERs regulate the development or functional responses of innate immune cells.

  2. DMPD: When signaling pathways collide: positive and negative regulation of toll-likereceptor signal transduction. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18631453 When signaling pathways collide: positive and negative regulation of toll-...l) Show When signaling pathways collide: positive and negative regulation of toll-likereceptor signal transd...uction. PubmedID 18631453 Title When signaling pathways collide: positive and neg

  3. YAP regulates neuronal differentiation through Sonic hedgehog signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yi-Ting; Ding, Jing-Ya [Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan (China); Li, Ming-Yang [Department of Life Science, National Taiwan Normal University, Taipei 116, Taiwan (China); Yeh, Tien-Shun [Department of Anatomy and Cell Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Wang, Tsu-Wei, E-mail: twwang@ntnu.edu.tw [Department of Life Science, National Taiwan Normal University, Taipei 116, Taiwan (China); Yu, Jenn-Yah, E-mail: jyyu@ym.edu.tw [Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan (China); Brain Research Center, National Yang-Ming University, Taipei 112, Taiwan (China)

    2012-09-10

    Tight regulation of cell numbers by controlling cell proliferation and apoptosis is important during development. Recently, the Hippo pathway has been shown to regulate tissue growth and organ size in Drosophila. In mammalian cells, it also affects cell proliferation and differentiation in various tissues, including the nervous system. Interplay of several signaling cascades, such as Notch, Wnt, and Sonic Hedgehog (Shh) pathways, control cell proliferation during neuronal differentiation. However, it remains unclear whether the Hippo pathway coordinates with other signaling cascades in regulating neuronal differentiation. Here, we used P19 cells, a mouse embryonic carcinoma cell line, as a model to study roles of YAP, a core component of the Hippo pathway, in neuronal differentiation. P19 cells can be induced to differentiate into neurons by expressing a neural bHLH transcription factor gene Ascl1. Our results showed that YAP promoted cell proliferation and inhibited neuronal differentiation. Expression of Yap activated Shh but not Wnt or Notch signaling activity during neuronal differentiation. Furthermore, expression of Yap increased the expression of Patched homolog 1 (Ptch1), a downstream target of the Shh signaling. Knockdown of Gli2, a transcription factor of the Shh pathway, promoted neuronal differentiation even when Yap was over-expressed. We further demonstrated that over-expression of Yap inhibited neuronal differentiation in primary mouse cortical progenitors and Gli2 knockdown rescued the differentiation defect in Yap over-expressing cells. In conclusion, our study reveals that Shh signaling acts downstream of YAP in regulating neuronal differentiation. -- Highlights: Black-Right-Pointing-Pointer YAP promotes cell proliferation and inhibits neuronal differentiation in P19 cells. Black-Right-Pointing-Pointer YAP promotes Sonic hedgehog signaling activity during neuronal differentiation. Black-Right-Pointing-Pointer Knockdown of Gli2 rescues the Yap

  4. Kinase/phosphatase overexpression reveals pathways regulating hippocampal neuron morphology.

    Science.gov (United States)

    Buchser, William J; Slepak, Tatiana I; Gutierrez-Arenas, Omar; Bixby, John L; Lemmon, Vance P

    2010-07-01

    Development and regeneration of the nervous system requires the precise formation of axons and dendrites. Kinases and phosphatases are pervasive regulators of cellular function and have been implicated in controlling axodendritic development and regeneration. We undertook a gain-of-function analysis to determine the functions of kinases and phosphatases in the regulation of neuron morphology. Over 300 kinases and 124 esterases and phosphatases were studied by high-content analysis of rat hippocampal neurons. Proteins previously implicated in neurite growth, such as ERK1, GSK3, EphA8, FGFR, PI3K, PKC, p38, and PP1a, were confirmed to have effects in our functional assays. We also identified novel positive and negative neurite growth regulators. These include neuronal-developmentally regulated kinases such as the activin receptor, interferon regulatory factor 6 (IRF6) and neural leucine-rich repeat 1 (LRRN1). The protein kinase N2 (PKN2) and choline kinase alpha (CHKA) kinases, and the phosphatases PPEF2 and SMPD1, have little or no established functions in neuronal function, but were sufficient to promote neurite growth. In addition, pathway analysis revealed that members of signaling pathways involved in cancer progression and axis formation enhanced neurite outgrowth, whereas cytokine-related pathways significantly inhibited neurite formation.

  5. Epigenetic regulator Lid maintains germline stem cells through regulating JAK-STAT signaling pathway activity

    Directory of Open Access Journals (Sweden)

    Lama Tarayrah

    2015-11-01

    Full Text Available Signaling pathways and epigenetic mechanisms have both been shown to play essential roles in regulating stem cell activity. While the role of either mechanism in this regulation is well established in multiple stem cell lineages, how the two mechanisms interact to regulate stem cell activity is not as well understood. Here we report that in the Drosophila testis, an H3K4me3-specific histone demethylase encoded by little imaginal discs (lid maintains germline stem cell (GSC mitotic index and prevents GSC premature differentiation. Lid is required in germ cells for proper expression of the Stat92E transcription factor, the downstream effector of the Janus kinase signal transducer and activator of transcription (JAK-STAT signaling pathway. Our findings support a germ cell autonomous role for the JAK-STAT pathway in maintaining GSCs and place Lid as an upstream regulator of this pathway. Our study provides new insights into the biological functions of a histone demethylase in vivo and sheds light on the interaction between epigenetic mechanisms and signaling pathways in regulating stem cell activities.

  6. New insights into transduction pathways that regulate boar sperm function.

    Science.gov (United States)

    Hurtado de Llera, A; Martin-Hidalgo, D; Gil, M C; Garcia-Marin, L J; Bragado, M J

    2016-01-01

    Detailed molecular mechanisms mediating signal transduction cascades that regulate boar sperm function involving Ser/Thr and tyrosine phosphorylation of proteins have been reviewed previously. Therefore, this review will focus in those kinase pathways identified recently (boar spermatozoa that regulate different functional spermatozoa processes. AMP-activated protein kinase (AMPK) is a cell energy sensor kinase that was first identified in mammalian spermatozoa in 2012, and since then it has emerged as an essential regulator of boar sperm function. Signaling pathways leading to AMPK activation in boar sperm are highlighted in this review (PKA, CaMKKα/β, and PKC as well as Ca(2+) and cAMP messengers as upstream regulators). Interestingly, stimuli considered as cell stress (hyperosmotic stress, inhibition of mitochondrial activity, absence of intracellular Ca(2+)) markedly activate AMPK in boar spermatozoa. Moreover, AMPK plays a remarkable and necessary regulatory role in mammalian sperm function, controlling essential boar sperm functional processes such as motility, viability, mitochondrial membrane potential, organization and fluidity of plasma membrane, and outer acrosome membrane integrity. These mentioned processes are all required under fluctuating environment of spermatozoa when transiting through the female reproductive tract to achieve fertilization. An applied role of AMPK in artificial insemination techniques is also suggested as during boar seminal doses preservation at 17 °C, physiological levels of AMPK activity markedly increase (maximum on Day 7) and result essential to maintain the aforementioned fundamental sperm processes. Moreover, regulation of sperm function exerted by the glycogen synthase kinase 3 and Src family kinase pathways is summarized.

  7. Copper as a key regulator of cell signalling pathways.

    Science.gov (United States)

    Grubman, Alexandra; White, Anthony R

    2014-05-22

    Copper is an essential element in many biological processes. The critical functions associated with copper have resulted from evolutionary harnessing of its potent redox activity. This same property also places copper in a unique role as a key modulator of cell signal transduction pathways. These pathways are the complex sequence of molecular interactions that drive all cellular mechanisms and are often associated with the interplay of key enzymes including kinases and phosphatases but also including intracellular changes in pools of smaller molecules. A growing body of evidence is beginning to delineate the how, when and where of copper-mediated control over cell signal transduction. This has been driven by research demonstrating critical changes to copper homeostasis in many disorders including cancer and neurodegeneration and therapeutic potential through control of disease-associated cell signalling changes by modulation of copper-protein interactions. This timely review brings together for the first time the diverse actions of copper as a key regulator of cell signalling pathways and discusses the potential strategies for controlling disease-associated signalling processes using copper modulators. It is hoped that this review will provide a valuable insight into copper as a key signal regulator and stimulate further research to promote our understanding of copper in disease and therapy.

  8. Regulation of the pentose phosphate pathway in cancer.

    Science.gov (United States)

    Jiang, Peng; Du, Wenjing; Wu, Mian

    2014-01-01

    Energy metabolism is significantly reprogrammed in many human cancers, and these alterations confer many advantages to cancer cells, including the promotion of biosynthesis, ATP generation, detoxification and support of rapid proliferation. The pentose phosphate pathway (PPP) is a major pathway for glucose catabolism. The PPP directs glucose flux to its oxidative branch and produces a reduced form of nicotinamide adenine dinucleotide phosphate (NADPH), an essential reductant in anabolic processes. It has become clear that the PPP plays a critical role in regulating cancer cell growth by supplying cells with not only ribose-5-phosphate but also NADPH for detoxification of intracellular reactive oxygen species, reductive biosynthesis and ribose biogenesis. Thus, alteration of the PPP contributes directly to cell proliferation, survival and senescence. Furthermore, recent studies have shown that the PPP is regulated oncogenically and/or metabolically by numerous factors, including tumor suppressors, oncoproteins and intracellular metabolites. Dysregulation of PPP flux dramatically impacts cancer growth and survival. Therefore, a better understanding of how the PPP is reprogrammed and the mechanism underlying the balance between glycolysis and PPP flux in cancer will be valuable in developing therapeutic strategies targeting this pathway.

  9. Planar cell polarity pathway regulates nephrin endocytosis in developing podocytes.

    Science.gov (United States)

    Babayeva, Sima; Rocque, Brittany; Aoudjit, Lamine; Zilber, Yulia; Li, Jane; Baldwin, Cindy; Kawachi, Hiroshi; Takano, Tomoko; Torban, Elena

    2013-08-16

    The noncanonical Wnt/planar cell polarity (PCP) pathway controls a variety of cell behaviors such as polarized protrusive cell activity, directional cell movement, and oriented cell division and is crucial for the normal development of many tissues. Mutations in the PCP genes cause malformation in multiple organs. Recently, the PCP pathway was shown to control endocytosis of PCP and non-PCP proteins necessary for cell shape remodeling and formation of specific junctional protein complexes. During formation of the renal glomerulus, the glomerular capillary becomes enveloped by highly specialized epithelial cells, podocytes, that display unique architecture and are connected via specialized cell-cell junctions (slit diaphragms) that restrict passage of protein into the urine; podocyte differentiation requires active remodeling of cytoskeleton and junctional protein complexes. We report here that in cultured human podocytes, activation of the PCP pathway significantly stimulates endocytosis of the core slit diaphragm protein, nephrin, via a clathrin/β-arrestin-dependent endocytic route. In contrast, depletion of the PCP protein Vangl2 leads to an increase of nephrin at the cell surface; loss of Vangl2 functions in Looptail mice results in disturbed glomerular maturation. We propose that the PCP pathway contributes to podocyte development by regulating nephrin turnover during junctional remodeling as the cells differentiate.

  10. Dicer-dependent pathways regulate chondrocyte proliferation and differentiation.

    Science.gov (United States)

    Kobayashi, Tatsuya; Lu, Jun; Cobb, Bradley S; Rodda, Stephen J; McMahon, Andrew P; Schipani, Ernestina; Merkenschlager, Matthias; Kronenberg, Henry M

    2008-02-12

    Small noncoding RNAs, microRNAs (miRNAs), bind to messenger RNAs through base pairing to suppress gene expression. Despite accumulating evidence that miRNAs play critical roles in various biological processes across diverse organisms, their roles in mammalian skeletal development have not been demonstrated. Here, we show that Dicer, an essential component for biogenesis of miRNAs, is essential for normal skeletal development. Dicer-null growth plates show a progressive reduction in the proliferating pool of chondrocytes, leading to severe skeletal growth defects and premature death of mice. The reduction of proliferating chondrocytes in Dicer-null growth plates is caused by two distinct mechanisms: decreased chondrocyte proliferation and accelerated differentiation into postmitotic hypertrophic chondrocytes. These defects appear to be caused by mechanisms downstream or independent of the Ihh-PTHrP signaling pathway, a pivotal signaling system that regulates chondrocyte proliferation and differentiation. Microarray analysis of Dicer-null chondrocytes showed limited expression changes in miRNA-target genes, suggesting that, in the majority of cases, chondrocytic miRNAs do not directly regulate target RNA abundance. Our results demonstrate the critical role of the Dicer-dependent pathway in the regulation of chondrocyte proliferation and differentiation during skeletal development.

  11. Regulation of ribosomal DNA amplification by the TOR pathway.

    Science.gov (United States)

    Jack, Carmen V; Cruz, Cristina; Hull, Ryan M; Keller, Markus A; Ralser, Markus; Houseley, Jonathan

    2015-08-01

    Repeated regions are widespread in eukaryotic genomes, and key functional elements such as the ribosomal DNA tend to be formed of high copy repeated sequences organized in tandem arrays. In general, high copy repeats are remarkably stable, but a number of organisms display rapid ribosomal DNA amplification at specific times or under specific conditions. Here we demonstrate that target of rapamycin (TOR) signaling stimulates ribosomal DNA amplification in budding yeast, linking external nutrient availability to ribosomal DNA copy number. We show that ribosomal DNA amplification is regulated by three histone deacetylases: Sir2, Hst3, and Hst4. These enzymes control homologous recombination-dependent and nonhomologous recombination-dependent amplification pathways that act in concert to mediate rapid, directional ribosomal DNA copy number change. Amplification is completely repressed by rapamycin, an inhibitor of the nutrient-responsive TOR pathway; this effect is separable from growth rate and is mediated directly through Sir2, Hst3, and Hst4. Caloric restriction is known to up-regulate expression of nicotinamidase Pnc1, an enzyme that enhances Sir2, Hst3, and Hst4 activity. In contrast, normal glucose concentrations stretch the ribosome synthesis capacity of cells with low ribosomal DNA copy number, and we find that these cells show a previously unrecognized transcriptional response to caloric excess by reducing PNC1 expression. PNC1 down-regulation forms a key element in the control of ribosomal DNA amplification as overexpression of PNC1 substantially reduces ribosomal DNA amplification rate. Our results reveal how a signaling pathway can orchestrate specific genome changes and demonstrate that the copy number of repetitive DNA can be altered to suit environmental conditions.

  12. Regulation of DNA double-strand break repair pathway choice

    Institute of Scientific and Technical Information of China (English)

    Meena Shrivastav; Leyma P De Haro; Jac A Nickoloff

    2008-01-01

    DNA double-strand breaks (DSBs) are critical lesions that can result in cell death or a wide variety of genetic alterations including large- or small-scale deletions, loss of heterozygosity, translocations, and chromosome loss. DSBs are repaired by non-homologous end-joining (NHEJ) and homologous recombination (HR), and defects in these pathways cause genome instability and promote tumorigenesis. DSBs arise from endogenous sources includ-ing reactive oxygen species generated during cellular metabolism, collapsed replication forks, and nucleases, and from exogenous sources including ionizing radiation and chemicals that directly or indirectly damage DNA and are commonly used in cancer therapy. The DSB repair pathways appear to compete for DSBs, but the balance between them differs widely among species, between different cell types of a single species, and during different cell cycle phases of a single cell type. Here we review the regulatory factors that regulate DSB repair by NHEJ and HR in yeast and higher eukaryotes. These factors include regulated expression and phosphorylation of repair proteins, chromatin modulation of repair factor accessibility, and the availability of homologous repair templates. While most DSB repair proteins appear to function exclusively in NHEJ or HR, a number of proteins influence both pathways, including the MRE11/RAD50/NBS1 (XRS2) complex, BRCA1, histone H2AX, PARP-1, RAD18, DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and ATM. DNA-PKcs plays a role in mammalian NHEJ, but it also influences HR through a complex regulatory network that may involve crosstalk with ATM, and the regulation of at least 12 proteins involved in HR that are phosphorylated by DNA-PKcs and/or ATM.

  13. The Pentose Phosphate Pathway Regulates the Circadian Clock.

    Science.gov (United States)

    Rey, Guillaume; Valekunja, Utham K; Feeney, Kevin A; Wulund, Lisa; Milev, Nikolay B; Stangherlin, Alessandra; Ansel-Bollepalli, Laura; Velagapudi, Vidya; O'Neill, John S; Reddy, Akhilesh B

    2016-09-13

    The circadian clock is a ubiquitous timekeeping system that organizes the behavior and physiology of organisms over the day and night. Current models rely on transcriptional networks that coordinate circadian gene expression of thousands of transcripts. However, recent studies have uncovered phylogenetically conserved redox rhythms that can occur independently of transcriptional cycles. Here we identify the pentose phosphate pathway (PPP), a critical source of the redox cofactor NADPH, as an important regulator of redox and transcriptional oscillations. Our results show that genetic and pharmacological inhibition of the PPP prolongs the period of circadian rhythms in human cells, mouse tissues, and fruit flies. These metabolic manipulations also cause a remodeling of circadian gene expression programs that involves the circadian transcription factors BMAL1 and CLOCK, and the redox-sensitive transcription factor NRF2. Thus, the PPP regulates circadian rhythms via NADPH metabolism, suggesting a pivotal role for NADPH availability in circadian timekeeping.

  14. Bioinformatic dissecting of TP53 regulation pathway underlying butyrate-induced histone modification in epigenetic regulation

    Science.gov (United States)

    Butyrate affects cell proliferation, differentiation and motility. Butyrate inhibits histone deacetylase (HDAC) activities and induces cell cycle arrest and apoptosis. TP53 is one of the most active upstream regulators discovered by IPA in our RNA sequencing data set. The TP53 signaling pathway pl...

  15. Regulation of the MAPK pathway by raf kinase inhibitory protein.

    Science.gov (United States)

    Vandamme, Drieke; Herrero, Ana; Al-Mulla, Fahd; Kolch, Walter

    2014-01-01

    The Raf kinase inhibitor protein 1 (RKIP-1) was the first reported endogenous inhibitor of Raf-1-MEK-ERK/MAPK cascade, by interfering with the phosphorylation of MEK by Raf-1. However, RKIP's functions related to the MAPK signaling are far more complex. Newer data indicate that by modulating different protein-protein interactions, RKIP is involved in fine-tuning cell signaling, modulating ERK dynamics, and regulating cross talk between different pathways. Here, we describe the molecular mechanisms by which RKIP controls MAPK signaling at different levels and vice versa and its regulation via feedback phosphorylation. We also focus on several discrepancies and questions that remain, such as the RKIP binding regulation by Raf-1 N-region phosphorylation, the possible B-Raf inhibition, and the effects of RKIP-lipid binding. We also describe how RKIP's role as key signaling modulator of many cell fate decisions leads to the fact that fine control of RKIP activity and regulation is crucial to avoid pathological processes, such as metastasis, pulmonary arterial hypertension, and heart failure.

  16. Integration of Shh and Wnt Signaling Pathways Regulating Hematopoiesis.

    Science.gov (United States)

    Zhou, Zhigang; Wan, Liping; Wang, Chun; Zhou, Kun

    2015-12-01

    To investigate the spatial and temporal programmed expression of Shh and Wnt members during key stages of definitive hematopoiesis and the possible mechanism of Shh and Wnt signaling pathways regulating the proliferation of hematopoietic progenitor cells (HPCs). Spatial and temporal programmed gene expression of Shh and Wnt signaling during hematopoiesis corresponded with c-kit(+)lin(-) HPCs proliferation. C-kit(+)Lin(-) populations derived from aorta-gonad-mesonephros (AGM) of Balb/c mice at E10.5 with increased expression of Shh and Wnt3a demonstrated a greater potential for proliferation. Additionally, supplementation with soluble Shh N-terminal peptide promoted the proliferation of c-kit(+)Lin(-) populations by activating the Wnt signaling pathway, an effect which was inhibited by blocking Shh signaling. A specific inhibitor of wnt signaling was capable of inhibiting Shh-induced proliferation in a similar manner to shh inhibitor. Our results provide valuable information on Shh and Wnt signaling involved in hematopoiesis and highlight the importance of interaction of Shh and Wnt signaling in regulating HPCs proliferation.

  17. The chromatin remodeler SPLAYED regulates specific stress signaling pathways.

    Directory of Open Access Journals (Sweden)

    Justin W Walley

    2008-12-01

    Full Text Available Organisms are continuously exposed to a myriad of environmental stresses. Central to an organism's survival is the ability to mount a robust transcriptional response to the imposed stress. An emerging mechanism of transcriptional control involves dynamic changes in chromatin structure. Alterations in chromatin structure are brought about by a number of different mechanisms, including chromatin modifications, which covalently modify histone proteins; incorporation of histone variants; and chromatin remodeling, which utilizes ATP hydrolysis to alter histone-DNA contacts. While considerable insight into the mechanisms of chromatin remodeling has been gained, the biological role of chromatin remodeling complexes beyond their function as regulators of cellular differentiation and development has remained poorly understood. Here, we provide genetic, biochemical, and biological evidence for the critical role of chromatin remodeling in mediating plant defense against specific biotic stresses. We found that the Arabidopsis SWI/SNF class chromatin remodeling ATPase SPLAYED (SYD is required for the expression of selected genes downstream of the jasmonate (JA and ethylene (ET signaling pathways. SYD is also directly recruited to the promoters of several of these genes. Furthermore, we show that SYD is required for resistance against the necrotrophic pathogen Botrytis cinerea but not the biotrophic pathogen Pseudomonas syringae. These findings demonstrate not only that chromatin remodeling is required for selective pathogen resistance, but also that chromatin remodelers such as SYD can regulate specific pathways within biotic stress signaling networks.

  18. SIRT1 regulates MAPK pathways in vitiligo skin: insight into the molecular pathways of cell survival.

    Science.gov (United States)

    Becatti, Matteo; Fiorillo, Claudia; Barygina, Victoria; Cecchi, Cristina; Lotti, Torello; Prignano, Francesca; Silvestro, Agrippino; Nassi, Paolo; Taddei, Niccolò

    2014-03-01

    Vitiligo is an acquired and progressive hypomelanotic disease that manifests as circumscribed depigmented patches on the skin. The aetiology of vitiligo remains unclear, but recent experimental data underline the interactions between melanocytes and other typical skin cells, particularly keratinocytes. Our previous results indicate that keratinocytes from perilesional skin show the features of damaged cells. Sirtuins (silent mating type information regulation 2 homolog) 1, well-known modulators of lifespan in many species, have a role in gene repression, metabolic control, apoptosis and cell survival, DNA repair, development, inflammation, neuroprotection and healthy ageing. In the literature there is no evidence for SIRT1 signalling in vitiligo and its possible involvement in disease progression. Here, biopsies were taken from the perilesional skin of 16 patients suffering from non-segmental vitiligo and SIRT1 signalling was investigated in these cells. For the first time, a new SIRT1/Akt, also known as Protein Kinase B (PKB)/mitogen-activated protein kinase (MAPK) signalling has been revealed in vitiligo. SIRT1 regulates MAPK pathway via Akt-apoptosis signal-regulating kinase-1 and down-regulates pro-apoptotic molecules, leading to decreased oxidative stress and apoptotic cell death in perilesional vitiligo keratinocytes. We therefore propose SIRT1 activation as a novel way of protecting perilesional vitiligo keratinocytes from damage.

  19. Cross-regulation of signaling pathways: An example of nuclear hormone receptors and the canonical Wnt pathway

    Energy Technology Data Exchange (ETDEWEB)

    Beildeck, Marcy E. [Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road, NW, Washington, DC 20057 (United States); Gelmann, Edward P. [Columbia University, Department of Medicine, New York, NY (United States); Byers, Stephen W., E-mail: byerss@georgetown.edu [Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Road, NW, Washington, DC 20057 (United States)

    2010-07-01

    Predicting the potential physiological outcome(s) of any given molecular pathway is complex because of cross-talk with other pathways. This is particularly evident in the case of the nuclear hormone receptor and canonical Wnt pathways, which regulate cell growth and proliferation, differentiation, apoptosis, and metastatic potential in numerous tissues. These pathways are known to intersect at many levels: in the intracellular space, at the membrane, in the cytoplasm, and within the nucleus. The outcomes of these interactions are important in the control of stem cell differentiation and maintenance, feedback loops, and regulating oncogenic potential. The aim of this review is to demonstrate the importance of considering pathway cross-talk when predicting functional outcomes of signaling, using nuclear hormone receptor/canonical Wnt pathway cross-talk as an example.

  20. Regulation of multiple carbon monoxide consumption pathways in anaerobic bacteria

    Directory of Open Access Journals (Sweden)

    Stephen M Techtmann

    2011-07-01

    Full Text Available Carbon monoxide (CO, well known as a toxic gas, is increasingly recognized as a key metabolite and signaling molecule. Microbial utilization of CO is quite common, evidenced by the rapid escalation in description of new species of CO-utilizing bacteria and archaea. Carbon monoxide dehydrogenase (CODH, the protein complex that enables anaerobic CO utilization has been well-characterized from an increasing number of microorganisms, however the regulation of multiple CO-related gene clusters in single isolates remains unexplored. Many species are extroraordinarily resistant to high CO concentrations, thiriving under pure CO at more than one atmosphere. We hypothesized that, in strains that can grow exclusively on CO, both carbon acquisition via the CODH/Acetyl CoA synthase complex and energy conservation via a CODH-linked hydrogenase must be differentially regulated in response to the availability of CO. The CO-sensing transcriptional activator, CooA is present in most CO-oxidizing bacteria. Here we present a genomic and phylogenetic survey of CODH operons and cooA genes found in CooA-containing bacteria. Two distinct groups of CooA homologs were found: One clade (CooA-1 is found in the majority of CooA containing bacteria, whereas the other clade (CooA-2 is found only in genomes that encode multiple CODH clusters, suggesting that the CooA-2 might be important for cross-regulation of competing CODH operons. Recombinant CooA-1 and CooA-2 regulators from the prototypical CO-utilizing bacterium Carboxydothermus hydrogenoformans were purified, and promoter binding analyses revealed that CooA-1 specifically regulates the hydrogenase-linked CODH, whereas CooA-2 is able to regulate both the hydrogenase-linked CODH and the CODH/ACS operons. These studies point to the ability of dual CooA homologs to partition CO into divergent CO-utilizing pathways resulting in efficient consumption of a single limiting growth substrate available across a wide range of

  1. Cinnamon polyphenols regulate multiple metabolic pathways involved in intestinal lipid metabolism of primary small intestinal enterocytes

    Science.gov (United States)

    Increasing evidence suggests that dietary factors may affect the expression of multiple genes and signaling pathways including those that regulate intestinal lipoprotein metabolism. The small intestine is actively involved in the regulation of dietary lipid absorption, intracellular transport and me...

  2. DMPD: Convergence of the NF-kappaB and IRF pathways in the regulation of the innateantiviral response. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17706453 Convergence of the NF-kappaB and IRF pathways in the regulation of the innateanti... (.png) (.svg) (.html) (.csml) Show Convergence of the NF-kappaB and IRF pathways in the regulation of the innateanti... IRF pathways in the regulation of the innateantiviral response. Authors Hiscott J. Publication Cytokine Gro

  3. Altered Pathway Analyzer: A gene expression dataset analysis tool for identification and prioritization of differentially regulated and network rewired pathways

    Science.gov (United States)

    Kaushik, Abhinav; Ali, Shakir; Gupta, Dinesh

    2017-01-01

    Gene connection rewiring is an essential feature of gene network dynamics. Apart from its normal functional role, it may also lead to dysregulated functional states by disturbing pathway homeostasis. Very few computational tools measure rewiring within gene co-expression and its corresponding regulatory networks in order to identify and prioritize altered pathways which may or may not be differentially regulated. We have developed Altered Pathway Analyzer (APA), a microarray dataset analysis tool for identification and prioritization of altered pathways, including those which are differentially regulated by TFs, by quantifying rewired sub-network topology. Moreover, APA also helps in re-prioritization of APA shortlisted altered pathways enriched with context-specific genes. We performed APA analysis of simulated datasets and p53 status NCI-60 cell line microarray data to demonstrate potential of APA for identification of several case-specific altered pathways. APA analysis reveals several altered pathways not detected by other tools evaluated by us. APA analysis of unrelated prostate cancer datasets identifies sample-specific as well as conserved altered biological processes, mainly associated with lipid metabolism, cellular differentiation and proliferation. APA is designed as a cross platform tool which may be transparently customized to perform pathway analysis in different gene expression datasets. APA is freely available at http://bioinfo.icgeb.res.in/APA. PMID:28084397

  4. Controlled sumoylation of the mevalonate pathway enzyme HMGS-1 regulates metabolism during aging

    NARCIS (Netherlands)

    Sapir, Amir; Tsur, Assaf; Koorman, Thijs; Ching, Kaitlin; Mishra, Prashant; Bardenheier, Annabelle; Podolsky, Lisa; Bening-Abu-Shach, Ulrike; Boxem, Mike; Chou, Tsui-Fen; Broday, Limor; Sternberg, Paul W

    2014-01-01

    Many metabolic pathways are critically regulated during development and aging but little is known about the molecular mechanisms underlying this regulation. One key metabolic cascade in eukaryotes is the mevalonate pathway. It catalyzes the synthesis of sterol and nonsterol isoprenoids, such as chol

  5. Nrf2-driven TERT regulates pentose phosphate pathway in glioblastoma.

    Science.gov (United States)

    Ahmad, F; Dixit, D; Sharma, V; Kumar, A; Joshi, S D; Sarkar, C; Sen, E

    2016-05-05

    Given the involvement of telomerase activation and dysregulated metabolism in glioma progression, the connection between these two critical players was investigated. Pharmacological inhibition of human Telomerase reverse transcriptase (hTERT) by Costunolide induced glioma cell apoptosis in a reactive oxygen species (ROS)-dependent manner. Costunolide induced an ROS-dependent increase in p53 abrogated telomerase activity. Costunolide decreased Nrf2 level; and ectopic Nrf2 expression decreased Costunolide-induced ROS generation. While TERT knock-down abrogated Nrf2 levels, overexpression of Nrf2 increased TERT expression. Inhibition of hTERT either by Costunolide, or by siRNA or dominant-negative hTERT (DN-hTERT) abrogated (i) expression of Glucose-6-phosphate dehydrogenase (G6PD) and Transketolase (TKT) - two major nodes in the pentose phosphate (PPP) pathway; and (ii) phosphorylation of glycogen synthase (GS). hTERT knock-down decreased TKT activity and increased glycogen accumulation. Interestingly, siRNA-mediated knock-down of TKT elevated glycogen accumulation. Coherent with the in vitro findings, Costunolide reduced tumor burden in heterotypic xenograft glioma mouse model. Costunolide-treated tumors exhibited diminished TKT activity, heightened glycogen accumulation, and increased senescence. Importantly, glioblastoma multiforme (GBM) patient tumors bearing TERT promoter mutations (C228T and C250T) known to be associated with increased telomerase activity; exhibited elevated Nrf2 and TKT expression and decreased glycogen accumulation. Taken together, our findings highlight the previously unknown (i) role of telomerase in the regulation of PPP and glycogen accumulation and (ii) the involvement of Nrf2-TERT loop in maintaining oxidative defense responses in glioma cells.

  6. Regulation of cellular metabolism by the Notch receptor signalling pathway

    OpenAIRE

    2012-01-01

    Seven genes involved in metabolism were tested as direct targets of the Notch signalling pathway. For each gene the occupancy of its enhancers by Su(H), its transcriptional response to Notch pathway and its biological functionality was verified in vitro and in vivo.

  7. PCNA Modifications for Regulation of Post-Replication Repair Pathways

    OpenAIRE

    2008-01-01

    Stalled DNA replication forks activate specific DNA repair mechanism called post-replication repair (PRR) pathways that simply bypass DNA damage. The bypassing of DNA damage by PRR prevents prolonged stalling of DNA replication that could result in double strand breaks (DSBs). Proliferating cell nuclear antigen (PCNA) functions to initiate and choose different bypassing pathways of PRR. In yeast, DNA replication forks stalled by DNA damage induces monoubiquitination of PCNA at K164, which is ...

  8. Logical Analysis of Regulation of Interleukin-12 Expression Pathway Regulation During HCV Infection.

    Science.gov (United States)

    Farooqi, Zia-Ur-Rehman; Tareen, Samar H K; Ahmed, Jamil; Zaidi, Najam-Us-Sahar S

    2016-01-01

    Hepatitis C virus (HCV) triggers coordinated innate and adaptive response in host cell. HCV genome and proteins of the replicating virus are recognized as non-self-antigens by host cell to activate Toll Like Receptors (TLRs). Activated TLRs ultimately express cytokines, which can clear virus either by activating interferon (IFN), protein kinase C (PKC) and RNA Lase system or through activation of cytotoxic T-lymphocytes. Interleukin-12 (IL-12) is a potent antiviral cytokine, capable of clearing HCV by bridging both innate and adaptive antiviral immune response. Activation of TLR-4 on macrophages surface induces expression of IL-12 via NF-κB and AP-1 transcriptional pathway. After expression, IL- 12 releases IFN-γ, which activates anti-HCV cytotoxic lymphocytes. Conversely, in chronic HCV infection downregulation of IL-12 has been reported instead of by number of studies. Keeping in view of the above mentioned facts, this study was designed to evaluate HCV-core mediated down-regulation of IL-12 transcriptional pathway by employing a logical modeling approach based on the Ren´e Thomas formalism. The logical parameters of entities were estimated by using SMBioNet. The Logical model represents all possible dynamics of protein expression involved during course of HCV pathology. Results demonstrated that at chronic stage of infection, though TLR-4 was constantly active but yet it failed to express the NF-κB, AP-1, IL-12 and IFN-γ. This mechanism was indicative of incorporation of core mediated changes in IL-12 regulatory pathway. Moreover, results also indicate that HCV adopts different trajectories to accomplish the persistence of chronic phase of infection. It also implicated that human immune system tries to clear HCV but core is capable of inducing system oscillations to evade the immunity.

  9. Transcriptional repressor PRR5 directly regulates clock-output pathways

    OpenAIRE

    Nakamichi, Norihito; Kiba, Takatoshi; Kamioka, Mari; Suzuki, Takamasa; Yamashino, Takafumi; Higashiyama, Tetsuya; Sakakibara, Hitoshi; Mizuno, Takeshi

    2012-01-01

    The circadian clock is an endogenous time-keeping mechanism that enables organisms to adapt to external daily cycles. The clock coordinates biological activities with these cycles, mainly through genome-wide gene expression. However, the exact mechanism underlying regulation of circadian gene expression is poorly understood. Here we demonstrated that an Arabidopsis PSEUDO-RESPONSE REGULATOR 5 (PRR5), which acts in the clock genetic circuit, directly regulates expression timing of key transcri...

  10. Sensors and signal transduction pathways in vertebrate cell volume regulation

    DEFF Research Database (Denmark)

    Hoffmann, Else K; Pedersen, Stine F

    2006-01-01

    will be discussed. In contrast to the simple pathway of osmosensing in yeast, cells from vertebrate organisms appear to exhibit multiple volume sensing systems, the specific mechanism(s) activated being cell type- and stimulus-dependent. Candidate sensors include integrins and growth factor receptors, while other...

  11. Integrated Regulation of Toll-like Receptor Responses by Notch and Interferon-γ Pathways

    OpenAIRE

    2008-01-01

    Toll-like receptor (TLR) responses are regulated to avoid toxicity and achieve coordinated responses appropriate for the cell environment. We found that Notch and TLR pathways cooperated to activate canonical Notch target genes, including transcriptional repressors Hes1 and Hey1, and to increase production of canonical TLR-induced cytokines TNF, IL-6 and IL-12. Cooperation by these pathways to increase target gene expression was mediated the Notch pathway component and transcription factor RB...

  12. Mathematical modelling of the diurnal regulation of the MEP pathway in Arabidopsis.

    Science.gov (United States)

    Pokhilko, Alexandra; Bou-Torrent, Jordi; Pulido, Pablo; Rodríguez-Concepción, Manuel; Ebenhöh, Oliver

    2015-05-01

    Isoprenoid molecules are essential elements of plant metabolism. Many important plant isoprenoids, such as chlorophylls, carotenoids, tocopherols, prenylated quinones and hormones are synthesised in chloroplasts via the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway. Here we develop a mathematical model of diurnal regulation of the MEP pathway in Arabidopsis thaliana. We used both experimental and theoretical approaches to integrate mechanisms potentially involved in the diurnal control of the pathway. Our data show that flux through the MEP pathway is accelerated in light due to the photosynthesis-dependent supply of metabolic substrates of the pathway and the transcriptional regulation of key biosynthetic genes by the circadian clock. We also demonstrate that feedback regulation of both the activity and the abundance of the first enzyme of the MEP pathway (1-deoxy-D-xylulose 5-phosphate synthase, DXS) by pathway products stabilizes the flux against changes in substrate supply and adjusts the flux according to product demand under normal growth conditions. These data illustrate the central relevance of photosynthesis, the circadian clock and feedback control of DXS for the diurnal regulation of the MEP pathway.

  13. The Hippo pathway regulates homeostatic growth of stem cell niche precursors in the Drosophila ovary.

    Science.gov (United States)

    Sarikaya, Didem P; Extavour, Cassandra G

    2015-02-01

    The Hippo pathway regulates organ size, stem cell proliferation and tumorigenesis in adult organs. Whether the Hippo pathway influences establishment of stem cell niche size to accommodate changes in organ size, however, has received little attention. Here, we ask whether Hippo signaling influences the number of stem cell niches that are established during development of the Drosophila larval ovary, and whether it interacts with the same or different effector signaling pathways in different cell types. We demonstrate that canonical Hippo signaling regulates autonomous proliferation of the soma, while a novel hippo-independent activity of Yorkie regulates autonomous proliferation of the germ line. Moreover, we demonstrate that Hippo signaling mediates non-autonomous proliferation signals between germ cells and somatic cells, and contributes to maintaining the correct proportion of these niche precursors. Finally, we show that the Hippo pathway interacts with different growth pathways in distinct somatic cell types, and interacts with EGFR and JAK/STAT pathways to regulate non-autonomous proliferation of germ cells. We thus provide evidence for novel roles of the Hippo pathway in establishing the precise balance of soma and germ line, the appropriate number of stem cell niches, and ultimately regulating adult female reproductive capacity.

  14. Regulation of the expression of the whole genome of Ustilago maydis by a MAPK pathway.

    Science.gov (United States)

    Martínez-Soto, Domingo; Ruiz-Herrera, José

    2015-05-01

    The operation of mitogen-activated protein kinase (MAPK) signal transduction pathways is one of the most important mechanisms for the transfer of extracellular information into the cell. These pathways are highly conserved in eukaryotic organisms. In fungi, MAPK pathways are involved in the regulation of a number of cellular processes such as metabolism, homeostasis, pathogenesis and cell differentiation and morphogenesis. Considering the importance of pathways, in the present work we proceeded to identify all the genes that are regulated by the signal transduction pathway involved in mating, pathogenesis and morphogenesis of Ustilago maydis. Accordingly we made a comparison between the transcriptomes from a wild-type strain and an Ubc2 mutant affected in the interacting protein of this pathway by use of microarrays. By this methodology, we identified 939 genes regulated directly or indirectly by the MAPK pathway. Of them, 432 were positively, and 507 were negatively found regulated. By functional grouping, genes encoding cyclin-dependent kinases, transcription factors, proteins involved in signal transduction, in synthesis of wall and cell membrane, and involved in dimorphism were identified as differentially regulated. These data reveal the importance of these global studies, and the large (and unsuspected) number of functions of the fungus under the control of this MAPK, providing clues to the possible mechanisms involved.

  15. The Retinoblastoma pathway regulates stem cell proliferation in freshwater planarians.

    Science.gov (United States)

    Zhu, Shu Jun; Pearson, Bret J

    2013-01-15

    Freshwater planarians are flatworms of the Lophotrochozoan superphylum and are well known for their regenerative abilities, which rely on a large population of pluripotent adult stem cells. However, the mechanisms by which planarians maintain a precise population of adult stem cells while balancing proliferation and cell death, remain to be elucidated. Here we have identified, characterized, and functionally tested the core Retinoblastoma (Rb) pathway components in planarian adult stem cell biology. The Rb pathway is an ancient and conserved mechanism of proliferation control from plants to animals and is composed of three core components: an Rb protein, and a transcription factor heterodimer of E2F and DP proteins. Although the planarian genome contains all components of the Rb pathway, we found that they have undergone gene loss from the ancestral state, similar to other species in their phylum. The single Rb homolog (Smed-Rb) was highly expressed in planarian stem cells and was required for stem cell maintenance, similar to the Rb-homologs p107 and p130 in vertebrates. We show that planarians and their phylum have undergone the most severe reduction in E2F genes observed thus far, and the single remaining E2F was predicted to be a repressive-type E2F (Smed-E2F4-1). Knockdown of either Smed-E2F4-1 or its dimerization partner Dp (Smed-Dp) by RNAi resulted in temporary hyper-proliferation. Finally, we showed that known Rb-interacting genes in other systems, histone deacetylase 1 and cyclinD (Smed-HDAC1; Smed-cycD), were similar to Rb in expression and phenotypes when knocked down by RNAi, suggesting that these established interactions with Rb may also be conserved in planarians. Together, these results showed that planarians use the conserved components of the Rb tumor suppressor pathway to control proliferation and cell survival.

  16. Regulation of the transforming growth factor β pathway by reversible ubiquitylation.

    Science.gov (United States)

    Al-Salihi, Mazin A; Herhaus, Lina; Sapkota, Gopal P

    2012-05-01

    The transforming growth factor β (TGFβ) signalling pathway plays a central role during embryonic development and in adult tissue homeostasis. It regulates gene transcription through a signalling cascade from cell surface receptors to intracellular SMAD transcription factors and their nuclear cofactors. The extent, duration and potency of signalling in response to TGFβ cytokines are intricately regulated by complex biochemical processes. The corruption of these regulatory processes results in aberrant TGFβ signalling and leads to numerous human diseases, including cancer. Reversible ubiquitylation of pathway components is a key regulatory process that plays a critical role in ensuring a balanced response to TGFβ signals. Many studies have investigated the mechanisms by which various E3 ubiquitin ligases regulate the turnover and activity of TGFβ pathway components by ubiquitylation. Moreover, recent studies have shed new light into their regulation by deubiquitylating enzymes. In this report, we provide an overview of current understanding of the regulation of TGFβ signalling by E3 ubiquitin ligases and deubiquitylases.

  17. Integration of Transcriptional and Posttranslational Regulation in a Glucose Signal Transduction Pathway in Saccharomyces cerevisiae

    OpenAIRE

    Kim, Jeong-Ho; Brachet, Valérie; Moriya, Hisao; Johnston, Mark

    2006-01-01

    Expression of the HXT genes encoding glucose transporters in the budding yeast Saccharomyces cerevisiae is regulated by two interconnected glucose-signaling pathways: the Snf3/Rgt2-Rgt1 glucose induction pathway and the Snf1-Mig1 glucose repression pathway. The Snf3 and Rgt2 glucose sensors in the membrane generate a signal in the presence of glucose that inhibits the functions of Std1 and Mth1, paralogous proteins that regulate the function of the Rgt1 transcription factor, which binds to th...

  18. Down-regulation of HIV-1 Infection by Inhibition of the MAPK Signaling Pathway

    Institute of Scientific and Technical Information of China (English)

    Jian Gong; Xi-hui Shen; Chao Chen; Hui Qiu; Rong-ge Yang

    2011-01-01

    The human immunodeficiency virus type 1(HIV-1)can interact with and exploit the host cellular machinery to replicate and propagate itself.Numerous studies have shown that the Mitogen-activated protein kinase(MAPK)signal pathway can positively regulate the replication of HIV-1,but exactly how each MAPK pathway affects HIV-1 infection and replication is not understood.In this study,we used the Extracellular signal-regulated kinase(ERK)pathway inhibitor,PD98059,the Jun N-terminal kinase(JNK)pathway inhibitor,SP600125,and the p38 pathway inhibitor,SB203580,to investigate the roles of these pathways in HIV-1replication.We found that application of PD98059 results in a strong VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus and HIV-1NL4-3 virus inhibition activity.In addition,SB203580 and SP600125 also elicited marked VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus inhibition activity but no HIV-1NL4-3 virus inhibition activity.We also found that SB203580 and SP600125 can enhance the HIV-1 inhibition activity of PD98059when cells were treated with all three MAPK pathway inhibitors in combination.Finally,we show that HIV-1virus inhibition activity of the MAPK pathway inhibitors was the result of the negative regulation of HIV-1 LTR promoter activity.

  19. Transcriptomic analysis in the developing zebrafish embryo after compound exposure: Individual gene expression and pathway regulation

    Energy Technology Data Exchange (ETDEWEB)

    Hermsen, Sanne A.B., E-mail: Sanne.Hermsen@rivm.nl [Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven (Netherlands); Department of Toxicogenomics, Maastricht University, P.O. Box 616, 6200 MD, Maastricht (Netherlands); Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.178, 3508 TD, Utrecht (Netherlands); Pronk, Tessa E. [Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven (Netherlands); Department of Toxicogenomics, Maastricht University, P.O. Box 616, 6200 MD, Maastricht (Netherlands); Brandhof, Evert-Jan van den [Centre for Environmental Quality, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven (Netherlands); Ven, Leo T.M. van der [Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven (Netherlands); Piersma, Aldert H. [Centre for Health Protection, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven (Netherlands); Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.178, 3508 TD, Utrecht (Netherlands)

    2013-10-01

    The zebrafish embryotoxicity test is a promising alternative assay for developmental toxicity. Classically, morphological assessment of the embryos is applied to evaluate the effects of compound exposure. However, by applying differential gene expression analysis the sensitivity and predictability of the test may be increased. For defining gene expression signatures of developmental toxicity, we explored the possibility of using gene expression signatures of compound exposures based on commonly expressed individual genes as well as based on regulated gene pathways. Four developmental toxic compounds were tested in concentration-response design, caffeine, carbamazepine, retinoic acid and valproic acid, and two non-embryotoxic compounds, D-mannitol and saccharin, were included. With transcriptomic analyses we were able to identify commonly expressed genes, which were mostly development related, after exposure to the embryotoxicants. We also identified gene pathways regulated by the embryotoxicants, suggestive of their modes of action. Furthermore, whereas pathways may be regulated by all compounds, individual gene expression within these pathways can differ for each compound. Overall, the present study suggests that the use of individual gene expression signatures as well as pathway regulation may be useful starting points for defining gene biomarkers for predicting embryotoxicity. - Highlights: • The zebrafish embryotoxicity test in combination with transcriptomics was used. • We explored two approaches of defining gene biomarkers for developmental toxicity. • Four compounds in concentration-response design were tested. • We identified commonly expressed individual genes as well as regulated gene pathways. • Both approaches seem suitable starting points for defining gene biomarkers.

  20. Protein Kinase Pathways That Regulate Neuronal Survival and Death

    Science.gov (United States)

    2004-08-01

    interneurons of the cerebellum, provide a good model for a maximal concentration of IGF-I (50 ng/ml). The phosphor- VOL. 20, 2000 REGULATION OF NEURONAL...Cell 6:233-244. 272:33271-33278. Lyons GE, Micales BK , Schwarz J, Martin JF, Olson EN (1995) Expres- Ornatsky 01, Cox DM, Tangirala P, Andreucci JJ

  1. MicroRNAs regulate mitochondrial apoptotic pathway in myocardial ischemia-reperfusion-injury.

    Science.gov (United States)

    Makhdoumi, Pouran; Roohbakhsh, Ali; Karimi, Gholamreza

    2016-12-01

    MicroRNAs (miRNAs) are small non-coding RNAs that act as post-transcriptional gene regulators. They are involved in the pathogenesis of different disorders including heart diseases. MiRNAs contribute to ischemia/reperfusion injury (I/RI) by altering numerous key signaling elements. Together with alterations in the various potential signaling pathways, modification in miRNA expression has been suggested as a part of the response network following ischemia/reperfusion (I/R). In addition, cardiac mitochondrial homeostasis is closely associated with cardiac function and impairment of mitochondrial activity occurred after ischemia/reperfusion injury. MiRNAs play a key role in the regulation of mitochondrial apoptotic pathway and signaling proteins. In this review, we summarize the knowledge currently available regarding the molecular mechanisms of miRNA-regulated mitochondrial functions during ischemia/reperfusion injury. This regulation occurs in different stages of mitochondrial apoptosis pathway.

  2. The ubiquitin–proteasome system and signal transduction pathways regulating Epithelial Mesenchymal transition of cancer

    Directory of Open Access Journals (Sweden)

    Voutsadakis Ioannis A

    2012-07-01

    Full Text Available Abstract Epithelial to Mesenchymal transition (EMT in cancer, a process permitting cancer cells to become mobile and metastatic, has a signaling hardwire forged from development. Multiple signaling pathways that regulate carcinogenesis enabling characteristics in neoplastic cells such as proliferation, resistance to apoptosis and angiogenesis are also the main players in EMT. These pathways, as almost all cellular processes, are in their turn regulated by ubiquitination and the Ubiquitin-Proteasome System (UPS. Ubiquitination is the covalent link of target proteins with the small protein ubiquitin and serves as a signal to target protein degradation by the proteasome or to other outcomes such as endocytosis, degradation by the lysosome or specification of cellular localization. This paper reviews signal transduction pathways regulating EMT and being regulated by ubiquitination.

  3. AMPK-independent pathways regulate skeletal muscle fatty acid oxidation

    DEFF Research Database (Denmark)

    Dzamko, Nicolas; Schertzer, Jonathan D.; Ryall, James G.;

    2008-01-01

    with rates of fatty acid oxidation. To address this issue we have investigated the requirement for skeletal muscle AMPK in controlling aminoimidazole-4-carboxymide-1-beta-d-ribofuranoside (AICAR) and contraction-stimulated fatty acid oxidation utilizing transgenic mice expressing a muscle-specific kinase......-based approach we identified 18 Ser/Thr protein kinases whose phosphorylation was increased by greater than 25% in contracted KD relative to WT muscle. Utilizing bioinformatics we predicted that extracellular regulated protein-serine kinase (ERK1/2), inhibitor of nuclear factor (NF)-kappaB protein-serine kinase...... beta (IKKbeta) and protein kinase D (PKD) may phosphorylate ACC2 at Ser-221 but during in vitro phosphorylation assays only AMPK phosphorylated ACC2. These data demonstrate that AMPK is not essential for the regulation of fatty acid oxidation by AICAR or muscle contraction....

  4. Protein Kinase D Regulates Cell Death Pathways in Experimental Pancreatitis

    OpenAIRE

    Yuan, Jingzhen; Liu, Yannan; Tan, Tanya; Guha, Sushovan; Gukovsky, Ilya; Gukovskaya, Anna; Pandol, Stephen J.

    2012-01-01

    Inflammation and acinar cell necrosis are two major pathological responses of acute pancreatitis, a serious disorder with no current therapies directed to its molecular pathogenesis. Serine/threonine protein kinase D family, which includes PKD/PKD1, PKD2, and PKD3, has been increasingly implicated in the regulation of multiple physiological and pathophysiological effects. We recently reported that PKD/PKD1, the predominant PKD isoform expressed in rat pancreatic acinar cells, mediates early e...

  5. MAPK signal pathways in the regulation of cell proliferation in mammalian cells

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    MAPK families play an important role in complex cellular programs like proliferation, differentiation,development, transformation, and apoptosis. At least three MAPK families have been characterized: extracellular signal-regulated kinase (ERK), Jun kinase (JNK/SAPK) and p38 MAPK. The above effects are fulfilled by regulation of cell cycle engine and other cell proliferation related proteins. In this paper we discussed their functions and cooperation with other signal pathways in regulation of cell proliferation.

  6. PDP-1 links the TGF-β and IIS pathways to regulate longevity, development, and metabolism.

    Directory of Open Access Journals (Sweden)

    Sri Devi Narasimhan

    2011-04-01

    Full Text Available The insulin/IGF-1 signaling (IIS pathway is a conserved regulator of longevity, development, and metabolism. In Caenorhabditis elegans IIS involves activation of DAF-2 (insulin/IGF-1 receptor tyrosine kinase, AGE-1 (PI 3-kinase, and additional downstream serine/threonine kinases that ultimately phosphorylate and negatively regulate the single FOXO transcription factor homolog DAF-16. Phosphatases help to maintain cellular signaling homeostasis by counterbalancing kinase activity. However, few phosphatases have been identified that negatively regulate the IIS pathway. Here we identify and characterize pdp-1 as a novel negative modulator of the IIS pathway. We show that PDP-1 regulates multiple outputs of IIS such as longevity, fat storage, and dauer diapause. In addition, PDP-1 promotes DAF-16 nuclear localization and transcriptional activity. Interestingly, genetic epistasis analyses place PDP-1 in the DAF-7/TGF-β signaling pathway, at the level of the R-SMAD proteins DAF-14 and DAF-8. Further investigation into how a component of TGF-β signaling affects multiple outputs of IIS/DAF-16, revealed extensive crosstalk between these two well-conserved signaling pathways. We find that PDP-1 modulates the expression of several insulin genes that are likely to feed into the IIS pathway to regulate DAF-16 activity. Importantly, dysregulation of IIS and TGF-β signaling has been implicated in diseases such as Type 2 Diabetes, obesity, and cancer. Our results may provide a new perspective in understanding of the regulation of these pathways under normal conditions and in the context of disease.

  7. Inhibitory neural pathway regulating gastric emptying in rats.

    Science.gov (United States)

    Ishiguchi, T; Nishioka, S; Takahashi, T

    2000-02-14

    The relaxation of the pylorus is one of the most important factors for promoting gastric emptying. However, the role of inhibitory neurotransmitters in the regulation of pyloric relaxation and gastric emptying remains unclear. In this study, we investigated the effects of NO biosynthesis inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), and calcium dependent potassium channel blocker, apamin, on vagal stimulation-induced pyloric relaxation and gastric emptying in rats. Sodium nitroprusside (SNP), adenosine 5'-triphosphate (ATP), vasoactive intestinal polypeptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP) caused pyloric relaxations in a dose dependent manner in vivo. Apamin (120 microg/kg) significantly reduced ATP and PACAP-induced pyloric relaxations without affecting SNP- or VIP-induced relaxations. Vagal stimulation (10 V, 1 ms, 1-20 Hz)-induced pyloric relaxation was significantly inhibited by L-NAME (10 mg/kg). The combined administration of L-NAME and apamin almost completely abolished vagal stimulation-induced pyloric relaxation. L-NAME and apamin significantly increased spontaneous contractions in the antrum, pylorus and duodenum. Increased motility index by L-NAME and apamin was significantly higher in the pylorus and duodenum, compared to that of antrum. L-NAME and apamin significantly delayed liquid gastric emptying. These results suggest that besides NO, probably ATP and PACAP, act as inhibitory neurotransmitters in the rat pylorus and regulate gastric emptying.

  8. dRYBP contributes to the negative regulation of the Drosophila Imd pathway.

    Directory of Open Access Journals (Sweden)

    Ricardo Aparicio

    Full Text Available The Drosophila humoral innate immune response fights infection by producing antimicrobial peptides (AMPs through the microbe-specific activation of the Toll or the Imd signaling pathway. Upon systemic infection, the production of AMPs is both positively and negatively regulated to reach a balanced immune response required for survival. Here, we report the function of the dRYBP (drosophila Ring and YY1 Binding Protein protein, which contains a ubiquitin-binding domain, in the Imd pathway. We have found that dRYBP contributes to the negative regulation of AMP production: upon systemic infection with Gram-negative bacteria, Diptericin expression is up-regulated in the absence of dRYBP and down-regulated in the presence of high levels of dRYBP. Epistatic analyses using gain and loss of function alleles of imd, Relish, or skpA and dRYBP suggest that dRYBP functions upstream or together with SKPA, a member of the SCF-E3-ubiquitin ligase complex, to repress the Imd signaling cascade. We propose that the role of dRYBP in the regulation of the Imd signaling pathway is to function as a ubiquitin adaptor protein together with SKPA to promote SCF-dependent proteasomal degradation of Relish. Beyond the identification of dRYBP as a novel component of Imd pathway regulation, our results also suggest that the evolutionarily conserved RYBP protein may be involved in the human innate immune response.

  9. Expression of brain-derived neurotrophic factor (BDNF) is regulated by the Wnt signaling pathway

    OpenAIRE

    Yi, Hyun; Hu, Jianfei; Qian, Jiang; Hackam, Abigail S.

    2012-01-01

    BDNF is a well-characterized neurotrophin that mediates a wide variety of activities in the central nervous system (CNS), including neuronal differentiation, neuroprotection and synaptic plasticity. The canonical Wnt signaling pathway is a critical regulator of embryonic development and homeostasis in adult tissues. Our group and others recently demonstrated that Wnt signaling induces BDNF expression in neurons and glia. However, the precise relationship between BDNF and Wnt signaling pathway...

  10. Role of bile acids in the regulation of the metabolic pathways

    Institute of Scientific and Technical Information of China (English)

    Hiroki; Taoka; Yoko; Yokoyama; Kohkichi; Morimoto; Naho; Kitamura; Tatsuya; Tanigaki; Yoko; Takashina; Kazuo; Tsubota; Mitsuhiro; Watanabe

    2016-01-01

    Recent studies have revealed that bile acids(BAs)are not only facilitators of dietary lipid absorption but also important signaling molecules exerting multiple physiological functions.Some major signaling pathways involving the nuclear BAs receptor farnesoid X receptor and the G protein-coupled BAs receptor TGR5/M-BAR have been identified to be the targets of BAs.BAs regulate their own homeostasis via signaling pathways.BAs also affect diverse metabolic pathways including glucose metabolism,lipid metabolism and energy expenditure.This paper suggests the mechanism of controlling metabolism via BA signaling and demonstrates that BA signaling is an attractive therapeutic target of the metabolic syndrome.

  11. Quercitrin attenuates osteoporosis in ovariectomized rats by regulating mitogen-activated protein kinase (MAPK) signaling pathways.

    Science.gov (United States)

    Xing, Li-Zhi; Ni, Huai-Jun; Wang, Yu-Ling

    2017-03-13

    MAPK signaling pathways are crucial in regulating osteogenesis, a genetic disorder affecting the bones. Quercitrin, a type of flavonoid, is widely distributed in nature and involved in many pharmacological activities. But its osteoprotective functions and mechanism in osteoporosis are far from being understood clearly. In this paper, the MAPK upregulation was observed in the ovariectomy-induced bone loss. Quercitrin was found to downregulate MAPK signaling pathways and prevent the ovariectomy-induced deterioration of bone mineral density (BMD), trabecular microstructure, and bone mechanical characteristics. In this study, quercitrin was seen to prevent the progression of the postmenopausal osteoporosis among the rats, which may be mediated by the downregulated MAPK signaling pathways.

  12. Regulation of apoptotic signal transduction pathways by the heat shock proteins

    Institute of Scientific and Technical Information of China (English)

    LI; Zhengyu; ZHAO; Xia; WEI; Yuquan

    2004-01-01

    The study about apoptotic signal transductions has become a project to reveal the molecular mechanisms of apoptosis. Heat shock proteins (hsps), which play an important role in cell growth and apoptosis, have attracted great attentions. A lot of researches have showed there is a hsps superfamily including hsp90, hsp70, hsp60 and hsp27, etc., which regulates the biological behaviors of cells, particularly apoptotic signal transduction in Fas pathway, JNK/SAPK pathway and caspases pathway at different levels, partly by the function of molecular chaperone.

  13. The maternal JAK/STAT pathway of Drosophila regulates embryonic dorsal-ventral patterning

    Directory of Open Access Journals (Sweden)

    Lopes E.S.S.

    2004-01-01

    Full Text Available Activation of NFkappaB plays a pivotal role in many cellular processes such as inflammation, proliferation and apoptosis. In Drosophila, nuclear translocation of the NFkappaB-related transcription factor Dorsal is spatially regulated in order to subdivide the embryo into three primary dorsal-ventral (DV domains: the ventral presumptive mesoderm, the lateral neuroectoderm and the dorsal ectoderm. Ventral activation of the Toll receptor induces degradation of the IkappaB-related inhibitor Cactus, liberating Dorsal for nuclear translocation. In addition, other pathways have been suggested to regulate Dorsal. Signaling through the maternal BMP member Decapentaplegic (Dpp inhibits Dorsal translocation along a pathway parallel to and independent of Toll. In the present study, we show for the first time that the maternal JAK/STAT pathway also regulates embryonic DV patterning. Null alleles of loci coding for elements of the JAK/STAT pathway, hopscotch (hop, marelle (mrl and zimp (zimp, modify zygotic expression along the DV axis. Genetic analysis suggests that the JAK kinase Hop, most similar to vertebrate JAK2, may modify signals downstream of Dpp. In addition, an activated form of Hop results in increased levels of Cactus and Dorsal proteins, modifying the Dorsal/Cactus ratio and consequently DV patterning. These results indicate that different maternal signals mediated by the Toll, BMP and JAK/STAT pathways may converge to regulate NFkappaB activity in Drosophila.

  14. Molecular Pathways: Regulation and Therapeutic Implications of Multidrug Resistance

    Science.gov (United States)

    Chen, Kevin G.; Sikic, Branimir I.

    2012-01-01

    Multidrug transporters constitute major mechanisms of multidrug resistance (MDR) in human cancers. The ABCB1 (MDR1) gene encodes a well-characterized transmembrane transporter, termed P-glycoprotein (P-gp), which is expressed in many normal human tissues and cancers. P-gp plays a major role in the distribution and excretion of drugs, and is involved in intrinsic and acquired drug resistance of cancers. The regulation of ABCB1 expression is complex, and has not been well studied in a clinical setting. In this review, we elucidate molecular signaling and epigenetic interactions that govern ABCB1 expression and the development of MDR in cancer. We focus on acquired expression of ABCB1 that is associated with genomic instability of cancer cells, including mutational events that alter chromatin structures, gene rearrangements, and mutations in tumor suppressor proteins (e.g., mutant p53) that guard the integrity of genome. In addition, epigenetic modifications of the ABCB1 proximal and far upstream promoters by either demethylation of DNA or acetylation of histone H3 play a pivotal role in inducing ABCB1 expression. We describe a molecular network that coordinates genetic and epigenetic events leading to the activation of ABCB1. These mechanistic insignts provide additional translational targets and potential strategies to deal with clinical MDR. PMID:22344233

  15. Inhibition of Notch pathway prevents osteosarcoma growth by cell cycle regulation.

    Science.gov (United States)

    Tanaka, M; Setoguchi, T; Hirotsu, M; Gao, H; Sasaki, H; Matsunoshita, Y; Komiya, S

    2009-06-16

    The study shows constitutive activation of the Notch pathway in various types of malignancies. However, it remains unclear how the Notch pathway is involved in the pathogenesis of osteosarcoma. We investigated the expression of the Notch pathway molecules in osteosarcoma biopsy specimens and examined the effect of Notch pathway inhibition. Real-time PCR revealed overexpression of Notch2, Jagged1, HEY1, and HEY2. On the other hand, Notch1 and DLL1 were downregulated in biopsy specimens. Notch pathway inhibition using gamma-secretase inhibitor and CBF1 siRNA slowed the growth of osteosarcomas in vitro. In addition, gamma-secretase inhibitor-treated xenograft models exhibited significantly slower osteosarcoma growth. Cell cycle analysis revealed that gamma-secretase inhibitor promoted G1 arrest. Real-time PCR and western blot revealed that gamma-secretase inhibitor reduced the expression of accelerators of the cell cycle, including cyclin D1, cyclin E1, E2, and SKP2. On the other hand, p21(cip1) protein, a cell cycle suppressor, was upregulated by gamma-secretase inhibitor treatment. These findings suggest that inhibition of Notch pathway suppresses osteosarcoma growth by regulation of cell cycle regulator expression and that the inactivation of the Notch pathway may be a useful approach to the treatment of patients with osteosarcoma.

  16. The flavonoid pathway regulates the petal colors of cotton flower.

    Directory of Open Access Journals (Sweden)

    Jiafu Tan

    Full Text Available Although biochemists and geneticists have studied the cotton flower for more than one century, little is known about the molecular mechanisms underlying the dramatic color change that occurs during its short developmental life following blooming. Through the analysis of world cotton germplasms, we found that all of the flowers underwent color changes post-anthesis, but there is a diverse array of petal colors among cotton species, with cream, yellow and red colors dominating the color scheme. Genetic and biochemical analyses indicated that both the original cream and red colors and the color changes post-anthesis were related to flavonoid content. The anthocyanin content and the expression of biosynthesis genes were both increased from blooming to one day post-anthesis (DPA when the flower was withering and undergoing abscission. Our results indicated that the color changes and flavonoid biosynthesis of cotton flowers were precisely controlled and genetically regulated. In addition, flavonol synthase (FLS genes involved in flavonol biosynthesis showed specific expression at 11 am when the flowers were fully opened. The anthocyanidin reductase (ANR genes, which are responsible for proanthocyanidins biosynthesis, showed the highest expression at 6 pm on 0 DPA, when the flowers were withered. Light showed primary, moderate and little effects on flavonol, anthocyanin and proanthocyanidin biosynthesis, respectively. Flavonol biosynthesis was in response to light exposure, while anthocyanin biosynthesis was involved in flower color changes. Further expression analysis of flavonoid genes in flowers of wild type and a flavanone 3-hydroxylase (F3H silenced line showed that the development of cotton flower color was controlled by a complex interaction between genes and light. These results present novel information regarding flavonoids metabolism and flower development.

  17. Tbx2 regulates anterior neural specification by repressing FGF signaling pathway.

    Science.gov (United States)

    Cho, Gun-Sik; Park, Dong-Seok; Choi, Sun-Cheol; Han, Jin-Kwan

    2017-01-15

    During early embryogenesis, FGF signals regulate the antero-posterior (AP) patterning of the neural plate by promoting posterior cell fates. In particular, BMP signal-mediated attenuation of FGF pathway plays a critical role in the determination of the anterior neural region. Here we show that Tbx2, a T-box transcriptional repressor regulates anterior neural specification by suppressing FGF8 signaling pathway in Xenopus embryo. Tbx2 is expressed in the anterior edge of the neural plate in early neurulae. Overexpression and knockdown of Tbx2 induce expansion and reduction in the expression of anterior neural markers, respectively. It also suppresses FGF8-induced ERK phosphorylation and neural caudalization. Tbx2, which is a target gene of BMP signal, down-regulates FGF8 signaling by inhibiting the expression of Flrt3, a positive regulator of this pathway. We found that Tbx2 binds directly to the T-box element located in the promoter region of Flrt3 gene, thereby interfering with the activity of the promoter. Consistently, Tbx2 augmentation of anterior neural formation is inhibited by co-expression of Flrt3. Furthermore, disruption of the anterior-most structures such as eyes in Tbx2-depleted embryos can be rescued by inhibition of Flrt3 function or FGF signaling. Taken together, our results suggest that Tbx2 mediates BMP signal to down-regulate FGF signaling pathway by repressing Flrt3 expression for anterior tissue formation.

  18. Interspecies Complementation of the LuxR Family Pathway-Specific Regulator Involved in Macrolide Biosynthesis.

    Science.gov (United States)

    Mo, SangJoon; Yoon, Yeo Joon

    2016-01-01

    PikD is a widely known pathway-specific regulator for controlling pikromycin production in Streptomyces venezuelae ATCC 15439, which is a representative of the large ATP-binding regulator of the LuxR family (LAL) in Streptomyces sp. RapH and FkbN also belong to the LAL family of transcriptional regulators, which show greatest homology with the ATP-binding motif and helix-turn-helix DNA-binding motif of PikD. Overexpression of pikD and heterologous expression of rapH and fkbN led to enhanced production of pikromycin by approximately 1.8-, 1.6-, and 1.6-fold in S. venezuelae, respectively. Cross-complementation of rapH and fkbN in the pikD deletion mutant (ΔpikD) restored pikromycin and derived macrolactone production. Overall, these results show that heterologous expression of rapH and fkbN leads to the overproduction of pikromycin and its congeners from the pikromycin biosynthetic pathway in S. venezuelae, and they have the same functionality as the pathwayspecific transcriptional activator for the pikromycin biosynthetic pathway in the ΔpikD strain. These results also show extensive "cross-communication" between pathway-specific regulators of streptomycetes and suggest revision of the current paradigm for pathwayspecific versus global regulation of secondary metabolism in Streptomyces species.

  19. Claudin-7 indirectly regulates the integrin/FAK signaling pathway in human colon cancer tissue.

    Science.gov (United States)

    Ding, Lei; Wang, Liyong; Sui, Leiming; Zhao, Huanying; Xu, Xiaoxue; Li, Tengyan; Wang, Xiaonan; Li, Wenjing; Zhou, Ping; Kong, Lu

    2016-08-01

    The claudin family of proteins is integral to the structure and function of tight junctions. The role of claudin-7 (Cldn-7, CLDN7) in regulating the integrin/focal adhesion kinase (FAK)/ERK signaling pathway remains poorly understood. Therefore, we investigated differences in gene expression, primarily focusing on CLDN7 and integrin/FAK/ERK signaling pathway genes, between colon cancer and adjacent normal tissues. Quantitative real-time reverse transcription-PCR and immunohistochemistry were utilized to verify the results of mRNA and protein expression, respectively. In silico analysis was used to predict co-regulation between Cldn-7 and integrin/FAK/ERK signaling pathway components, and the STRING database was used to analyze protein-protein interaction pairs among these proteins. Meta-analysis of expression microarrays in The Cancer Genome Atlas (TCGA) database was used to identify significant correlations between Cldn-7 and components of predicted genes in the integrin/FAK/ERK signaling pathway. Our results showed marked cancer stage-specific decreases in the protein expression of Cldn-7, Gelsolin, MAPK1 and MAPK3 in colon cancer samples, and the observed changes for all proteins except Cldn-7 were in agreement with changes in the corresponding mRNA levels. Cldn-7 might indirectly regulate MAPK3 via KRT8 due to KRT8 co-expression with MAPK3 or CLDN7. Our bioinformatics methods supported the hypothesis that Cldn-7 does not directly regulate any genes in the integrin/FAK/ERK signaling pathway. These factors may participate in a common network that regulates cancer progression in which the MAPK pathway serves as the central node.

  20. A constitutive active MAPK/ERK pathway due to BRAFV600E positively regulates AHR pathway in PTC.

    Science.gov (United States)

    Occhi, Gianluca; Barollo, Susi; Regazzo, Daniela; Bertazza, Loris; Galuppini, Francesca; Guzzardo, Vincenza; Jaffrain-Rea, Marie Lise; Vianello, Federica; Ciato, Denis; Ceccato, Filippo; Watutantrige-Fernando, Sara; Bisognin, Andrea; Bortoluzzi, Stefania; Pennelli, Gianmaria; Boscaro, Marco; Scaroni, Carla; Mian, Caterina

    2015-10-13

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor mediating the toxicity and tumor-promoting properties of dioxin. AHR has been reported to be overexpressed and constitutively active in a variety of solid tumors, but few data are currently available concerning its role in thyroid cancer. In this study we quantitatively explored a series of 51 paired-normal and papillary thyroid carcinoma (PTC) tissues for AHR-related genes. We identified an increased AHR expression/activity in PTC, independently from its nuclear dimerization partner and repressor but strictly related to a constitutive active MAPK/ERK pathway. The AHR up-regulation followed by an increased expression of AHR target genes was confirmed by a meta-analysis of published microarray data, suggesting a ligand-independent active AHR pathway in PTC. In-vitro studies using a PTC-derived cell line (BCPAP) and HEK293 cells showed that BRAFV600E may directly modulate AHR localization, induce AHR expression and activity in an exogenous ligand-independent manner. The AHR pathway might represent a potential novel therapeutic target for PTC in the clinical practice.

  1. A constitutive active MAPK/ERK pathway due to BRAFV600E positively regulates AHR pathway in PTC

    Science.gov (United States)

    Regazzo, Daniela; Bertazza, Loris; Galuppini, Francesca; Guzzardo, Vincenza; Jaffrain-Rea, Marie Lise; Vianello, Federica; Ciato, Denis; Ceccato, Filippo; Watutantrige-Fernando, Sara; Bisognin, Andrea; Bortoluzzi, Stefania; Pennelli, Gianmaria; Boscaro, Marco; Scaroni, Carla; Mian, Caterina

    2015-01-01

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor mediating the toxicity and tumor-promoting properties of dioxin. AHR has been reported to be overexpressed and constitutively active in a variety of solid tumors, but few data are currently available concerning its role in thyroid cancer. In this study we quantitatively explored a series of 51 paired-normal and papillary thyroid carcinoma (PTC) tissues for AHR-related genes. We identified an increased AHR expression/activity in PTC, independently from its nuclear dimerization partner and repressor but strictly related to a constitutive active MAPK/ERK pathway. The AHR up-regulation followed by an increased expression of AHR target genes was confirmed by a meta-analysis of published microarray data, suggesting a ligand-independent active AHR pathway in PTC. In-vitro studies using a PTC-derived cell line (BCPAP) and HEK293 cells showed that BRAFV600E may directly modulate AHR localization, induce AHR expression and activity in an exogenous ligand-independent manner. The AHR pathway might represent a potential novel therapeutic target for PTC in the clinical practice. PMID:26392334

  2. Recent Advances in the Regulation of Brassinosteroid Signaling and Biosynthesis Pathways

    Institute of Scientific and Technical Information of China (English)

    Huaxun Ye; Lei Li; Yanhai Yin

    2011-01-01

    Brassinosteroids (BRs) play important roles in plant growth, development and responses to environmental cues. BRs signal through plasma membrane receptor BRI1 and co-receptor BAK1, and several positive (BSK1, BSU1, PP2A) and negative (BKI1, BIN2 and 14-3-3) regulators to control the activities of BES1 and BZR1 family transcription factors,which regulate the expression of hundreds to thousands of genes for various BR responses. Recent studies identified novel signaling components in the BR pathways and started to establish the detailed mechanisms on the regulation of BR signaling. In addition, the molecular mechanism and transcriptional network through which BES1 and BZR1 control gene expression and various BR responses are beginning to be revealed. BES1 recruits histone demethylases ELF6 and REF6 as well as a transcription elongation factor IWS1 to regulate target gene expression. Identification of BES1 and BZR1 target genes established a transcriptional network for BR response and crosstalk with other signaling pathways. Recent studies also revealed regulatory mechanisms of BRs in many developmental processes and regulation of BR biosynthesis. Here we provide an overview and discuss some of the most recent progress in the regulation of BR signaling and biosynthesis pathways.

  3. Regulation of hematopoiesis and the hematopoietic stem cell niche by Wnt signaling pathways

    Institute of Scientific and Technical Information of China (English)

    Michael J Nemeth; David M Bodine

    2007-01-01

    Hematopoietic stem cells (HSCs) are a rare population of cells that are responsible for life-long generation of blood cells of all lineages. In order to maintain their numbers, HSCs must establish a balance between the opposing cell fates of self-renewal (in which the ability to function as HSCs is retained) and initiation of hematopoietic differentiation. Multiple signaling pathways have been implicated in the regulation of HSC cell fate. One such set of pathways are those activated by the Wnt family of ligands. Wnt signaling pathways play a crucial role during embryogenesis and deregulation of these pathways has been implicated in the formation of solid tumors. Wnt signaling also plays a role in the regulation of stem cells from multiple tissues, such as embryonic, epidermal, and intestinal stem cells. However, the function of Wnt signaling in HSC biology is still controversial. In this review, we will discuss the basic characteristics of the adult HSC and its regulatory microenvironment, the "niche", focusing on the regulation of the HSC and its niche by the Wnt signaling pathways.

  4. Is transcriptional regulation of metabolic pathways an optimal strategy for fitness?

    Directory of Open Access Journals (Sweden)

    Carl Troein

    Full Text Available BACKGROUND: Transcriptional regulation of the genes in metabolic pathways is a highly successful strategy, which is virtually universal in microorganisms. The lac operon of E. coli is but one example of how enzyme and transporter production can be made conditional on the presence of a nutrient to catabolize. METHODOLOGY: With a minimalist model of metabolism, cell growth and transcriptional regulation in a microorganism, we explore how the interaction between environmental conditions and gene regulation set the growth rate of cells in the phase of exponential growth. This in silico model, which is based on biochemical rate equations, does not describe a specific organism, but the magnitudes of its parameters are chosen to match realistic values. Optimizing the parameters of the regulatory system allows us to quantify the fitness benefit of regulation. When a second nutrient and its metabolic pathway are introduced, the system must further decide whether and how to activate both pathways. CONCLUSIONS: Even the crudest transcriptional network is shown to substantially increase the fitness of the organism, and this effect persists even when the range of nutrient levels is kept very narrow. We show that maximal growth is achieved when pathway activation is a more or less steeply graded function of the nutrient concentration. Furthermore, we predict that bistability of the system is a rare phenomenon in this context, but outline a situation where it may be selected for.

  5. Regulation of MAP kinase-dependent apoptotic pathway: implication of reactive oxygen and nitrogen species.

    Science.gov (United States)

    Sumbayev, Vadim V; Yasinska, Inna M

    2005-04-15

    Mitogen-activated protein (MAP) kinase signaling cascades are multi-functional signaling networks that influence cell growth, differentiation, apoptosis, and cellular responses to stress. Apoptosis signal-regulating kinase 1 (ASK1) is a MAP kinase kinase kinase that triggers apoptogenic kinase cascade leading to the phosphorylation/activation of c-Jun N-terminal kinases and p38-MAP kinase, which are responsible for inducing apoptotic cell death. This pathway plays a pivotal role in transduction of signals from different apoptotic stimuli. In the present review, we summarized the recent evidence concerning MAP kinase-dependent apoptotic pathway and its regulation in the mammalian cells and organism in vivo. We have shown that the key messengers of regulation of this pathway are the reactive oxygen and nitrogen species. The role of protein oxidation and S-nitrosation in induction of apoptotic cell death via ASK1 is discussed. Also we have outlined other recently discovered signal transduction processes involved in the regulation of ASK1 activity and downstream pathway.

  6. MicroRNAs Regulating Signaling Pathways: Potential Biomarkers in Systemic Sclerosis

    Directory of Open Access Journals (Sweden)

    Yisha Li

    2015-08-01

    Full Text Available Systemic sclerosis (SSc is a multisystem fibrotic and autoimmune disease. Both genetic and epigenetic elements mediate SSc pathophysiology. This review summarizes the role of one epigenetic element, known as microRNAs (miRNAs, involved in different signaling pathways of SSc pathogenesis. The expression of key components in transforming growth factor-β (TGF-β signaling pathway has been found to be regulated by miRNAs both upstream and downstream of TGF-β. We are specifically interested in the pathway components upstream of TGF-β, while miRNAs in other signaling pathways have not been extensively studied. The emerging role of miRNAs in vasculopathy of SSc suggests a promising new direction for future investigation. Elucidation of the regulatory role of miRNAs in the expression of signaling factors may facilitate the discovery of novel biomarkers in SSc and improve the understanding and treatment of this disease.

  7. MicroRNAs Regulating Signaling Pathways:Potential Biomarkers in Systemic Sclerosis

    Institute of Scientific and Technical Information of China (English)

    Yisha Li; Jing Huang; Muyao Guo; Xiaoxia Zuo

    2015-01-01

    Systemic sclerosis (SSc) is a multisystem fibrotic and autoimmune disease. Both genetic and epigenetic elements mediate SSc pathophysiology. This review summarizes the role of one epigenetic element, known as microRNAs (miRNAs), involved in different signaling pathways of SSc pathogenesis. The expression of key components in transforming growth factor-b (TGF-b) signaling pathway has been found to be regulated by miRNAs both upstream and downstream of TGF-b. We are specifically interested in the pathway components upstream of TGF-b, while miRNAs in other signaling pathways have not been extensively studied. The emerging role of miRNAs in vasculopathy of SSc suggests a promising new direction for future investigation. Elu-cidation of the regulatory role of miRNAs in the expression of signaling factors may facilitate the discovery of novel biomarkers in SSc and improve the understanding and treatment of this disease.

  8. PDK1-Akt pathway regulates radial neuronal migration and microtubules in the developing mouse neocortex.

    Science.gov (United States)

    Itoh, Yasuhiro; Higuchi, Maiko; Oishi, Koji; Kishi, Yusuke; Okazaki, Tomohiko; Sakai, Hiroshi; Miyata, Takaki; Nakajima, Kazunori; Gotoh, Yukiko

    2016-05-24

    Neurons migrate a long radial distance by a process known as locomotion in the developing mammalian neocortex. During locomotion, immature neurons undergo saltatory movement along radial glia fibers. The molecular mechanisms that regulate the speed of locomotion are largely unknown. We now show that the serine/threonine kinase Akt and its activator phosphoinositide-dependent protein kinase 1 (PDK1) regulate the speed of locomotion of mouse neocortical neurons through the cortical plate. Inactivation of the PDK1-Akt pathway impaired the coordinated movement of the nucleus and centrosome, a microtubule-dependent process, during neuronal migration. Moreover, the PDK1-Akt pathway was found to control microtubules, likely by regulating the binding of accessory proteins including the dynactin subunit p150(glued) Consistent with this notion, we found that PDK1 regulates the expression of cytoplasmic dynein intermediate chain and light intermediate chain at a posttranscriptional level in the developing neocortex. Our results thus reveal an essential role for the PDK1-Akt pathway in the regulation of a key step of neuronal migration.

  9. Time-course regulation of quercetin on cell survival/proliferation pathways in human hepatoma cells.

    Science.gov (United States)

    Granado-Serrano, Ana Belén; Angeles Martín, María; Bravo, Laura; Goya, Luis; Ramos, Sonia

    2008-04-01

    Quercetin, a dietary flavonoid, has been shown to possess anticarcinogenic properties, but the precise molecular mechanisms of action are not thoroughly elucidated. This study was aimed at investigating the time-course regulation effect of quercetin on survival/proliferation pathways in a human hepatoma cell line (HepG2). Quercetin induced a significant time-dependent inactivation of the major survival signaling proteins, i. e., phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B (AKT), extracellular regulated kinase (ERK), protein kinase C-alpha (PKC-alpha), in concert with a time-dependent activation of key death-related signals: c-jun amino-terminal kinase (JNK) and PKC-delta. These data suggest that quercetin exerts a tight regulation of survival/proliferation pathways that requires the integration of different signals and persists over time, being the balance of these regulatory signals what determines the fate of HepG2 cells.

  10. The STARS signaling pathway: a key regulator of skeletal muscle function.

    Science.gov (United States)

    Lamon, Séverine; Wallace, Marita A; Russell, Aaron P

    2014-09-01

    During the last decade, the striated muscle activator of Rho signaling (STARS), a muscle-specific protein, has been proposed to play an increasingly important role in skeletal muscle growth, metabolism, regeneration and stress adaptation. STARS influences actin dynamics and, as a consequence, regulates the myocardin-related transcription factor A/serum response factor (MRTF-A/SRF) transcriptional program, a well-known pathway controlling skeletal muscle development and function. Muscle-specific stress conditions, such as exercise, positively regulates, while disuse and degenerative muscle diseases are associated with a downregulation of STARS and its downstream partners, suggesting a pivotal role for STARS in skeletal muscle health. This review provides a comprehensive overview of the known role and regulation of STARS and the members of its signaling pathway, RhoA, MRTF-A and SRF, in skeletal muscle.

  11. The Atg1-Tor pathway regulates yolk catabolism in Drosophila embryos.

    Science.gov (United States)

    Kuhn, Hallie; Sopko, Richelle; Coughlin, Margaret; Perrimon, Norbert; Mitchison, Tim

    2015-11-15

    Yolk provides an important source of nutrients during the early development of oviparous organisms. It is composed mainly of vitellogenin proteins packed into membrane-bound compartments called yolk platelets. Catabolism of yolk is initiated by acidification of the yolk platelet, leading to the activation of Cathepsin-like proteinases, but it is unknown how this process is triggered. Yolk catabolism initiates at cellularization in Drosophila melanogaster embryos. Using maternal shRNA technology we found that yolk catabolism depends on the Tor pathway and on the autophagy-initiating kinase Atg1. Whereas Atg1 was required for a burst of spatially regulated autophagy during late cellularization, autophagy was not required for initiating yolk catabolism. We propose that the conserved Tor metabolic sensing pathway regulates yolk catabolism, similar to Tor-dependent metabolic regulation on the lysosome.

  12. A new pathway of glucocorticoid action for asthma treatment through the regulation of PTEN expression

    Directory of Open Access Journals (Sweden)

    Chen Qingge

    2011-04-01

    Full Text Available Abstract Background "Phosphatase and tensin homolog deleted on chromosome 10" (PTEN is mostly considered to be a cancer-related gene, and has been suggested to be a new pathway of pathogenesis of asthma. The purpose of this study was to investigate the effects of the glucocorticoid, dexamethasone, on PTEN regulation. Methods OVA-challenged mice were used as an asthma model to investigate the effect of dexamethasone on PTEN regulation. Immunohistochemistry was used to detect expression levels of PTEN protein in lung tissues. The human A549 cell line was used to explore the possible mechanism of action of dexamethasone on human PTEN regulation in vitro. A luciferase reporter construct under the control of PTEN promoter was used to confirm transcriptional regulation in response to dexamethasone. Results PTEN protein was found to be expressed at low levels in lung tissues in asthmatic mice; but the expression was restored after treatment with dexamethasone. In A549 cells, human PTEN was up-regulated by dexamethasone treatment. The promoter-reporter construct confirmed that dexamethasone could regulate human PTEN transcription. Treatment with the histone deacetylase inhibitor, TSA, could increase PTEN expression in A549 cells, while inhibition of histone acetylase (HAT by anacardic acid attenuated dexamethasone-induced PTEN expression. Conclusions Based on the data a new mechanism is proposed where glucocorticoids treat asthma partly through up-regulation of PTEN expression. The in vitro studies also suggest that the PTEN pathway may be involved in human asthma.

  13. Activation of the TOR Signalling Pathway by Glutamine Regulates Insect Fecundity.

    Science.gov (United States)

    Zhai, Yifan; Sun, Zhongxiang; Zhang, Jianqing; Kang, Kui; Chen, Jie; Zhang, Wenqing

    2015-05-29

    The target of rapamycin (TOR) positively controls cell growth in response to nutrients such as amino acids. However, research on the specific nutrients sensed by TOR is limited. Glutamine (Gln), a particularly important amino acid involved in metabolism in organisms, is synthesised and catalysed exclusively by glutamine synthetase (GS), and our previous studies have shown that Gln may regulate fecundity in vivo levels of the brown planthopper (BPH) Nilaparvata lugens. Until now, it has remained unclear whether Gln activates or inhibits the TOR signalling pathway. Here, we performed the combined analyses of iTRAQ (isobaric tags for relative and absolute quantification) and DGE (tag-based digital gene expression) data in N. lugens at the protein and transcript levels after GS RNAi, and we found that 52 pathways overlap, including the TOR pathway. We further experimentally demonstrate that Gln activates the TOR pathway by promoting the serine/threonine protein kinase AKT and inhibiting the 5'AMP-activated protein kinase AMPK phosphorylation activity in the pest. Furthermore, TOR regulates the fecundity of N. lugens probably by mediating vitellogenin (Vg) expression. This work is the first report that Gln activates the TOR pathway in vivo.

  14. The molecular choreography of protein synthesis: translational control, regulation, and pathways.

    Science.gov (United States)

    Chen, Jin; Choi, Junhong; O'Leary, Seán E; Prabhakar, Arjun; Petrov, Alexey; Grosely, Rosslyn; Puglisi, Elisabetta Viani; Puglisi, Joseph D

    2016-01-01

    Translation of proteins by the ribosome regulates gene expression, with recent results underscoring the importance of translational control. Misregulation of translation underlies many diseases, including cancer and many genetic diseases. Decades of biochemical and structural studies have delineated many of the mechanistic details in prokaryotic translation, and sketched the outlines of eukaryotic translation. However, translation may not proceed linearly through a single mechanistic pathway, but likely involves multiple pathways and branchpoints. The stochastic nature of biological processes would allow different pathways to occur during translation that are biased by the interaction of the ribosome with other translation factors, with many of the steps kinetically controlled. These multiple pathways and branchpoints are potential regulatory nexus, allowing gene expression to be tuned at the translational level. As research focus shifts toward eukaryotic translation, certain themes will be echoed from studies on prokaryotic translation. This review provides a general overview of the dynamic data related to prokaryotic and eukaryotic translation, in particular recent findings with single-molecule methods, complemented by biochemical, kinetic, and structural findings. We will underscore the importance of viewing the process through the viewpoints of regulation, translational control, and heterogeneous pathways.

  15. The SLIT-ROBO pathway: a regulator of cell function with implications for the reproductive system.

    Science.gov (United States)

    Dickinson, Rachel E; Duncan, W Colin

    2010-04-01

    The secreted SLIT glycoproteins and their Roundabout (ROBO) receptors were originally identified as important axon guidance molecules. They function as a repulsive cue with an evolutionarily conserved role in preventing axons from migrating to inappropriate locations during the assembly of the nervous system. In addition the SLIT-ROBO interaction is involved in the regulation of cell migration, cell death and angiogenesis and, as such, has a pivotal role during the development of other tissues such as the lung, kidney, liver and breast. The cellular functions that the SLIT/ROBO pathway controls during tissue morphogenesis are processes that are dysregulated during cancer development. Therefore inactivation of certain SLITs and ROBOs is associated with advanced tumour formation and progression in disparate tissues. Recent research has indicated that the SLIT/ROBO pathway could also have important functions in the reproductive system. The fetal ovary expresses most members of the SLIT and ROBO families. The SLITs and ROBOs also appear to be regulated by steroid hormones and regulate physiological cell functions in adult reproductive tissues such as the ovary and endometrium. Furthermore several SLITs and ROBOs are aberrantly expressed during the development of ovarian, endometrial, cervical and prostate cancer. This review will examine the roles this pathway could have in the development, physiology and pathology of the reproductive system and highlight areas for future research that could further dissect the influence of the SLIT/ROBO pathway in reproduction.

  16. Plasma membrane calcium ATPase proteins as novel regulators of signal transduction pathways

    Institute of Scientific and Technical Information of China (English)

    Mary; Louisa; Holton; Michael; Emerson; Ludwig; Neyses; Angel; L; Armesilla

    2010-01-01

    Emerging evidence suggests that plasma membrane calcium ATPases (PMCAs) play a key role as regulators of calcium-triggered signal transduction pathways via interaction with partner proteins. PMCAs regulate these pathways by targeting specific proteins to cellular sub-domains where the levels of intracellular freecalcium are kept low by the calcium ejection properties of PMCAs. According to this model, PMCAs have been shown to interact functionally with the calcium-sensitive proteins neuronal nitric oxide synthase, calmodulindependent serine protein kinase, calcineurin and endothelial nitric oxidase synthase. Transgenic animals with altered expression of PMCAs are being used to evaluate the physiological significance of these interactions. To date, PMCA interactions with calcium-dependent partner proteins have been demonstrated to play a crucial role in the pathophysiology of the cardiovascular system via regulation of the nitric oxide and calcineurin/nuclear factor of activated T cells pathways. This new evidence suggests that PMCAs play a more sophisticated role than the mere ejection of calcium from the cells, by acting as modulators of signaling transduction pathways.

  17. New insights into the regulation of plant immunity by amino acid metabolic pathways.

    Science.gov (United States)

    Zeier, Jürgen

    2013-12-01

    Besides defence pathways regulated by classical stress hormones, distinct amino acid metabolic pathways constitute integral parts of the plant immune system. Mutations in several genes involved in Asp-derived amino acid biosynthetic pathways can have profound impact on plant resistance to specific pathogen types. For instance, amino acid imbalances associated with homoserine or threonine accumulation elevate plant immunity to oomycete pathogens but not to pathogenic fungi or bacteria. The catabolism of Lys produces the immune signal pipecolic acid (Pip), a cyclic, non-protein amino acid. Pip amplifies plant defence responses and acts as a critical regulator of plant systemic acquired resistance, defence priming and local resistance to bacterial pathogens. Asp-derived pyridine nucleotides influence both pre- and post-invasion immunity, and the catabolism of branched chain amino acids appears to affect plant resistance to distinct pathogen classes by modulating crosstalk of salicylic acid- and jasmonic acid-regulated defence pathways. It also emerges that, besides polyamine oxidation and NADPH oxidase, Pro metabolism is involved in the oxidative burst and the hypersensitive response associated with avirulent pathogen recognition. Moreover, the acylation of amino acids can control plant resistance to pathogens and pests by the formation of protective plant metabolites or by the modulation of plant hormone activity.

  18. Regulation of hepatitis C virus replication and gene expression by the MAPK-ERK pathway.

    Science.gov (United States)

    Pei, Rongjuan; Zhang, Xiaoyong; Xu, Song; Meng, Zhongji; Roggendorf, Michael; Lu, Mengji; Chen, Xinwen

    2012-10-01

    The mitogen activated protein kinases-extracellular signal regulated kinases (MAPK-ERK) pathway is involved in regulation of multiple cellular processes including the cell cycle. In the present study using a Huh7 cell line Con1 with an HCV replicon, we have shown that the MAPK-ERK pathway plays a significant role in the modulation of HCV replication and protein expression and might influence IFN-α signalling. Epithelial growth factor (EGF) was able to stimulate ERK activation and decreased HCV RNA load while a MAPK-ERK pathway inhibitor U0126 led to an elevated HCV RNA load and higher NS5A protein amounts in Con1 cells. It could be further demonstrated that the inhibition of the MAPK-ERK pathway facilitated the translation directed by the HCV internal ribosome entry site. Consistently, a U0126 treatment enhanced activity of the HCV reporter replicon in transient transfection assays. Thus, the MAPK-ERK pathway plays an important role in the regulation of HCV gene expression and replication. In addition, cyclin-dependent kinases (CDKs) downstream of ERK may also be involved in the modulation of HCV replication since roscovitine, an inhibitor of CDKs had a similar effect to that of U0126. Modulation of the cell cycle progression by cell cycle inhibitor or RNAi resulted consistently in changes of HCV RNA levels. Further, the replication of HCV replicon in Con1 cells was inhibited by IFN-α. The inhibitory effect of IFN-α could be partly reversed by pre-incubation of Con-1 cells with inhibitors of the MAPK-ERK pathway and CDKs. It could be shown that the MAPK-ERK inhibitors are able to partially modulate the expression of interferon-stimulated genes.

  19. The neutral sphingomyelinase pathway regulates packaging of the prion protein into exosomes.

    Science.gov (United States)

    Guo, Belinda B; Bellingham, Shayne A; Hill, Andrew F

    2015-02-06

    Prion diseases are a group of transmissible, fatal neurodegenerative disorders associated with the misfolding of the host-encoded prion protein, PrP(C), into a disease-associated form, PrP(Sc). The transmissible prion agent is principally formed of PrP(Sc) itself and is associated with extracellular vesicles known as exosomes. Exosomes are released from cells both in vitro and in vivo, and have been proposed as a mechanism by which prions spread intercellularly. The biogenesis of exosomes occurs within the endosomal system, through formation of intraluminal vesicles (ILVs), which are subsequently released from cells as exosomes. ILV formation is known to be regulated by the endosomal sorting complexes required for transport (ESCRT) machinery, although an alternative neutral sphingomyelinase (nSMase) pathway has been suggested to also regulate this process. Here, we investigate a role for the nSMase pathway in exosome biogenesis and packaging of PrP into these vesicles. Inhibition of the nSMase pathway using GW4869 revealed a role for the nSMase pathway in both exosome formation and PrP packaging. In agreement, targeted knockdown of nSMase1 and nSMase2 in mouse neurons using lentivirus-mediated RNAi also decreases exosome release, demonstrating the nSMase pathway regulates the biogenesis and release of exosomes. We also demonstrate that PrP(C) packaging is dependent on nSMase2, whereas the packaging of disease-associated PrP(Sc) into exosomes occurs independently of nSMase2. These findings provide further insight into prion transmission and identify a pathway which directly assists exosome-mediated transmission of prions.

  20. Regulation of Hepatitis C Virus Replication and Gene Expression by the MAPK-ERK Pathway

    Institute of Scientific and Technical Information of China (English)

    Rongjuan Pei; Xiaoyong Zhang; Song Xu; Zhongji Meng; Michael Roggendorf; Mengji Lu; Xinwen Chen

    2012-01-01

    The mitogen activated protein kinases-extracellular signal regulated kinases (MAPK-ERK) pathway is involved in regulation of multiple cellular processes including the cell cycle.In the present study using a Huh7 cell line Con1 with an HCV replicon,we have shown that the MAPK-ERK pathway plays a significant role in the modulation of HCV replication and protein expression and might influence IFN-α signalling.Epithelial growth factor (EGF) was able to stimulate ERK activation and decreased HCV RNA load while a MAPK-ERK pathway inhibitor U0126 led to an elevated HCV RNA load and higher NS5A protein amounts in Con1 cells.It could be further demonstrated that the inhibition of the MAPK-ERK pathway facilitated the translation directed by the HCV internal ribosome entry site.Consistently,a U0126 treatment enhanced activity of the HCV reporter replicon in transient transfection assays.Thus,the MAPK-ERK pathway plays an important role in the regulation of HCV gene expression and replication.In addition,cyclin-dependent kinases (CDKs) downstream of ERK may also be involved in the modulation of HCV replication since roscovitine,an inhibitor of CDKs had a similar effect to that of U0126.Modulation of the cell cycle progression by cell cycle inhibitor or RNAi resulted consistently in changes of HCV RNA levels.Further,the replication of HCV replicon in Conl cells was inhibited by IFN-α.The inhibitory effect of IFN-α could be partly reversed by pre-incubation of Con-1 cells with inhibitors of the MAPK-ERK pathway and CDKs.It could be shown that the MAPK-ERK inhibitors are able to partially modulate the expression of interferon-stimulated genes.

  1. The TOR signaling pathway regulates vegetative development and virulence in Fusarium graminearum.

    Science.gov (United States)

    Yu, Fangwei; Gu, Qin; Yun, Yingzi; Yin, Yanni; Xu, Jin-Rong; Shim, Won-Bo; Ma, Zhonghua

    2014-07-01

    The target of rapamycin (TOR) signaling pathway plays critical roles in controlling cell growth in a variety of eukaryotes. However, the contribution of this pathway in regulating virulence of plant pathogenic fungi is unknown. We identified and characterized nine genes encoding components of the TOR pathway in Fusarium graminearum. Biological, genetic and biochemical functions of each component were investigated. The FgFkbp12-rapamycin complex binds to the FgTor kinase. The type 2A phosphatases FgPp2A, FgSit4 and FgPpg1 were found to interact with FgTap42, a downstream component of FgTor. Among these, we determined that FgPp2A is likely to be essential for F. graminearum survival, and FgSit4 and FgPpg1 play important roles in cell wall integrity by positively regulating the phosphorylation of FgMgv1, a key MAP kinase in the cell wall integrity pathway. In addition, the FgPpg1 interacting protein, FgTip41, is involved in regulating mycelial growth and virulence. Notably, FgTip41 does not interact with FgTap42 but with FgPpg1, suggesting the existence of FgTap42:FgPpg1:FgTip41 heterotrimer in F. graminearum, a complex not observed in the yeast model. Collectively, we defined a genetic regulatory framework that elucidates how the TOR pathway regulates virulence and vegetative development in F. graminearum.

  2. Hedgehog pathway regulators influence cervical cancer cell proliferation, survival and migration

    Energy Technology Data Exchange (ETDEWEB)

    Samarzija, Ivana [Ecole Polytechnique Federale Lausanne (EPFL), Department of Life Sciences, Swiss Institute for Experimental Cancer Research (ISREC), 1015 Lausanne (Switzerland); Beard, Peter, E-mail: peter.beard@epfl.ch [Ecole Polytechnique Federale Lausanne (EPFL), Department of Life Sciences, Swiss Institute for Experimental Cancer Research (ISREC), 1015 Lausanne (Switzerland)

    2012-08-17

    Highlights: Black-Right-Pointing-Pointer Unknown cellular mutations complement papillomavirus-induced carcinogenesis. Black-Right-Pointing-Pointer Hedgehog pathway components are expressed by cervical cancer cells. Black-Right-Pointing-Pointer Hedgehog pathway activators and inhibitors regulate cervical cancer cell biology. Black-Right-Pointing-Pointer Cell immortalization by papillomavirus and activation of Hedgehog are independent. -- Abstract: Human papillomavirus (HPV) infection is considered to be a primary hit that causes cervical cancer. However, infection with this agent, although needed, is not sufficient for a cancer to develop. Additional cellular changes are required to complement the action of HPV, but the precise nature of these changes is not clear. Here, we studied the function of the Hedgehog (Hh) signaling pathway in cervical cancer. The Hh pathway can have a role in a number of cancers, including those of liver, lung and digestive tract. We found that components of the Hh pathway are expressed in several cervical cancer cell lines, indicating that there could exists an autocrine Hh signaling loop in these cells. Inhibition of Hh signaling reduces proliferation and survival of the cervical cancer cells and induces their apoptosis as seen by the up-regulation of the pro-apoptotic protein cleaved caspase 3. Our results indicate that Hh signaling is not induced directly by HPV-encoded proteins but rather that Hh-activating mutations are selected in cells initially immortalized by HPV. Sonic Hedgehog (Shh) ligand induces proliferation and promotes migration of the cervical cancer cells studied. Together, these results indicate pro-survival and protective roles of an activated Hh signaling pathway in cervical cancer-derived cells, and suggest that inhibition of this pathway may be a therapeutic option in fighting cervical cancer.

  3. Utilization of economical substrate-derived carbohydrates by solventogenic clostridia: pathway dissection, regulation and engineering.

    Science.gov (United States)

    Gu, Yang; Jiang, Yu; Yang, Sheng; Jiang, Weihong

    2014-10-01

    Solventogenic clostridia can produce acetone, butanol and ethanol (ABE) by using different carbohydrates. For economical reasons, the utilization of cheap and renewable biomass in clostridia-based ABE fermentation has recently attracted increasing interests. With the study of molecular microbiology and development of genetic tools, the understanding of carbohydrate metabolism in clostridia has increased in recent years. Here, we review the pioneering work in this field, with a focus on dissecting the pathways and describing the regulation of the metabolism of economical substrate-derived carbohydrates by clostridia. Recent progress in the metabolic engineering of carbohydrate utilization pathways is also described.

  4. Nuclear mRNA degradation pathway(s are implicated in Xist regulation and X chromosome inactivation.

    Directory of Open Access Journals (Sweden)

    Constance Ciaudo

    2006-06-01

    Full Text Available A critical step in X-chromosome inactivation (XCI, which results in the dosage compensation of X-linked gene expression in mammals, is the coating of the presumptive inactive X chromosome by the large noncoding Xist RNA, which then leads to the recruitment of other factors essential for the heterochromatinisation of the inactive X and its transcriptional silencing. In an approach aimed at identifying genes implicated in the X-inactivation process by comparative transcriptional profiling of female and male mouse gastrula, we identified the Eif1 gene involved in translation initiation and RNA degradation. We show here that female embryonic stem cell lines, silenced by RNA interference for the Eif1 gene, are unable to form Xist RNA domains upon differentiation and fail to undergo X-inactivation. To probe further an effect involving RNA degradation pathways, the inhibition by RNA interference of Rent1, a factor essential for nonsense-mediated decay and Exosc10, a specific nuclear component of the exosome, was analysed and shown to similarly impair Xist upregulation and XCI. In Eif1-, Rent1-, and Exosc10-interfered clones, Xist spliced form(s are strongly downregulated, while the levels of unspliced form(s of Xist and the stability of Xist RNA remain comparable to that of the control cell lines. Our data suggests a role for mRNA nuclear degradation pathways in the critical regulation of spliced Xist mRNA levels and the onset of the X-inactivation process.

  5. Methionine sulfoxide reductase A regulates cell growth through the p53-p21 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seung Hee [Department of Biochemistry and Molecular Biology, Yeungnam University College of Medicine, Daegu 705-717 (Korea, Republic of); Kim, Hwa-Young, E-mail: hykim@ynu.ac.kr [Department of Biochemistry and Molecular Biology, Yeungnam University College of Medicine, Daegu 705-717 (Korea, Republic of)

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer Down-regulation of MsrA inhibits normal cell proliferation. Black-Right-Pointing-Pointer MsrA deficiency leads to an increase in p21 by enhanced p53 acetylation. Black-Right-Pointing-Pointer Down-regulation of MsrA causes cell cycle arrest at the G{sub 2}/M stage. Black-Right-Pointing-Pointer MsrA is a regulator of cell growth that mediates the p53-p21 pathway. -- Abstract: MsrA is an oxidoreductase that catalyzes the stereospecific reduction of methionine-S-sulfoxide to methionine. Although MsrA is well-characterized as an antioxidant and has been implicated in the aging process and cellular senescence, its roles in cell proliferation are poorly understood. Here, we report a critical role of MsrA in normal cell proliferation and describe the regulation mechanism of cell growth by this protein. Down-regulation of MsrA inhibited cell proliferation, but MsrA overexpression did not promote it. MsrA deficiency led to an increase in p21, a major cyclin-dependent kinase inhibitor, thereby causing cell cycle arrest at the G{sub 2}/M stage. While protein levels of p53 were not altered upon MsrA deficiency, its acetylation level was significantly elevated, which subsequently activated p21 transcription. The data suggest that MsrA is a regulator of cell growth that mediates the p53-p21 pathway.

  6. OTUB1 modulates c-IAP1 stability to regulate signalling pathways.

    Science.gov (United States)

    Goncharov, Tatiana; Niessen, Kyle; de Almagro, Maria Cristina; Izrael-Tomasevic, Anita; Fedorova, Anna V; Varfolomeev, Eugene; Arnott, David; Deshayes, Kurt; Kirkpatrick, Donald S; Vucic, Domagoj

    2013-04-17

    The cellular inhibitor of apoptosis (c-IAP) proteins are E3 ubiquitin ligases that are critical regulators of tumour necrosis factor (TNF) receptor (TNFR)-mediated signalling. Through their E3 ligase activity c-IAP proteins promote ubiquitination of receptor-interaction protein 1 (RIP1), NF-κB-inducing kinase (NIK) and themselves, and regulate the assembly of TNFR signalling complexes. Consequently, in the absence of c-IAP proteins, TNFR-mediated activation of NF-κB and MAPK pathways and the induction of gene expression are severely reduced. Here, we describe the identification of OTUB1 as a c-IAP-associated deubiquitinating enzyme that regulates c-IAP1 stability. OTUB1 disassembles K48-linked polyubiquitin chains from c-IAP1 in vitro and in vivo within the TWEAK receptor-signalling complex. Downregulation of OTUB1 promotes TWEAK- and IAP antagonist-stimulated caspase activation and cell death, and enhances c-IAP1 degradation. Furthermore, knockdown of OTUB1 reduces TWEAK-induced activation of canonical NF-κB and MAPK signalling pathways and modulates TWEAK-induced gene expression. Finally, suppression of OTUB1 expression in zebrafish destabilizes c-IAP (Birc2) protein levels and disrupts fish vasculature. These results suggest that OTUB1 regulates NF-κB and MAPK signalling pathways and TNF-dependent cell death by modulating c-IAP1 stability.

  7. The TOR signaling pathway regulates starvation-induced pseudouridylation of yeast U2 snRNA.

    Science.gov (United States)

    Wu, Guowei; Radwan, Mohamed K; Xiao, Mu; Adachi, Hironori; Fan, Jason; Yu, Yi-Tao

    2016-08-01

    Pseudouridine (Ψ) has been identified in various types of RNAs, including mRNA, rRNA, tRNA, snRNA, and many other noncoding RNAs. We have previously shown that RNA pseudouridylation, like DNA and protein modifications, can be induced by stress. For instance, growing yeast cells to saturation induces the formation of Ψ93 in U2 snRNA. Here, we further investigate this inducible RNA modification. We show that switching yeast cells from nutrient-rich medium to different nutrient-deprived media (including water) results in the formation of Ψ93 in U2 snRNA. Using gene deletion/conditional depletion as well as rapamycin treatment, we further show that the TOR signaling pathway, which controls cell entry into stationary phase, regulates Ψ93 formation. The RAS/cAMP signaling pathway, which parallels the TOR pathway, plays no role in this inducible modification.

  8. Agrin as a Mechanotransduction Signal Regulating YAP through the Hippo Pathway.

    Science.gov (United States)

    Chakraborty, Sayan; Njah, Kizito; Pobbati, Ajaybabu V; Lim, Ying Bena; Raju, Anandhkumar; Lakshmanan, Manikandan; Tergaonkar, Vinay; Lim, Chwee Teck; Hong, Wanjin

    2017-03-07

    The Hippo pathway effectors YAP and TAZ act as nuclear sensors of mechanical signals in response to extracellular matrix (ECM) cues. However, the identity and nature of regulators in the ECM and the precise pathways relaying mechanoresponsive signals into intracellular sensors remain unclear. Here, we uncover a functional link between the ECM proteoglycan Agrin and the transcriptional co-activator YAP. Importantly, Agrin transduces matrix and cellular rigidity signals that enhance stability and mechanoactivity of YAP through the integrin-focal adhesion- and Lrp4/MuSK receptor-mediated signaling pathways. Agrin antagonizes focal adhesion assembly of the core Hippo components by facilitating ILK-PAK1 signaling and negating the functions of Merlin and LATS1/2. We further show that Agrin promotes oncogenesis through YAP-dependent transcription and is clinically relevant in human liver cancer. We propose that Agrin acts as a mechanotransduction signal in the ECM.

  9. Agrin as a Mechanotransduction Signal Regulating YAP through the Hippo Pathway

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    Sayan Chakraborty

    2017-03-01

    Full Text Available The Hippo pathway effectors YAP and TAZ act as nuclear sensors of mechanical signals in response to extracellular matrix (ECM cues. However, the identity and nature of regulators in the ECM and the precise pathways relaying mechanoresponsive signals into intracellular sensors remain unclear. Here, we uncover a functional link between the ECM proteoglycan Agrin and the transcriptional co-activator YAP. Importantly, Agrin transduces matrix and cellular rigidity signals that enhance stability and mechanoactivity of YAP through the integrin-focal adhesion- and Lrp4/MuSK receptor-mediated signaling pathways. Agrin antagonizes focal adhesion assembly of the core Hippo components by facilitating ILK-PAK1 signaling and negating the functions of Merlin and LATS1/2. We further show that Agrin promotes oncogenesis through YAP-dependent transcription and is clinically relevant in human liver cancer. We propose that Agrin acts as a mechanotransduction signal in the ECM.

  10. Differential regulation of growth-promoting signalling pathways by E-cadherin.

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    Nikolaos T Georgopoulos

    Full Text Available BACKGROUND: Despite the well-documented association between loss of E-cadherin and carcinogenesis, as well as the link between restoration of its expression and suppression of proliferation in carcinoma cells, the ability of E-cadherin to modulate growth-promoting cell signalling in normal epithelial cells is less well understood and frequently contradictory. The potential for E-cadherin to co-ordinate different proliferation-associated signalling pathways has yet to be fully explored. METHODOLOGY/PRINCIPAL FINDINGS: Using a normal human urothelial (NHU cell culture system and following a calcium-switch approach, we demonstrate that the stability of NHU cell-cell contacts differentially regulates the Epidermal Growth Factor Receptor (EGFR/Extracellular Signal-Regulated Kinase (ERK and Phosphatidylinositol 3-Kinase (PI3-K/AKT pathways. We show that stable cell contacts down-modulate the EGFR/ERK pathway, whilst inducing PI3-K/AKT activity, which transiently enhances cell growth at low density. Functional inactivation of E-cadherin interferes with the capacity of NHU cells to form stable calcium-mediated contacts, attenuates E-cadherin-mediated PI3-K/AKT induction and enhances NHU cell proliferation by allowing de-repression of the EGFR/ERK pathway and constitutive activation of β-catenin-TCF signalling. CONCLUSIONS/SIGNIFICANCE: Our findings provide evidence that E-cadherin can differentially and concurrently regulate specific growth-related signalling pathways in a context-specific fashion, with direct, functional consequences for cell proliferation and population growth. Our observations not only reveal a novel, complex role for E-cadherin in normal epithelial cell homeostasis and tissue regeneration, but also provide the basis for a more complete understanding of the consequences of E-cadherin loss on malignant transformation.

  11. Zebrafish etv7 regulates red blood cell development through the cholesterol synthesis pathway

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    Anita M. Quintana

    2014-02-01

    Full Text Available ETV7 is a human oncoprotein that cooperates with Eμ-MYC to promote pre-B-cell leukemia in mice. It is normally expressed in the bone marrow and fetal liver and is upregulated in primary leukemia, suggesting that it is involved in proper hematopoiesis and leukemogenesis. ETV7 has been deleted in most rodents, but is conserved in all other vertebrates, including the zebrafish, Danio rerio. In this report, we characterize the function of the zebrafish etv7 gene during erythropoiesis. Our results demonstrate that etv7 regulates the expression of the zebrafish lanosterol synthase (lss gene, an essential gene in the cholesterol synthesis pathway. Furthermore, morpholino knockdown of etv7 leads to loss of hemoglobin-containing red blood cells, a phenotype that can be rescued by injection of exogenous cholesterol. We conclude that etv7 is essential for normal red blood cell development through regulation of the lss gene and the cholesterol synthesis pathway.

  12. Subcellular localization of frizzled receptors, mediated by their cytoplasmic tails, regulates signaling pathway specificity.

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    Jun Wu

    2004-07-01

    Full Text Available The Frizzled (Fz; called here Fz1 and Fz2 receptors have distinct signaling specificities activating either the canonical Wnt/beta-catenin pathway or Fz/planar cell polarity (PCP signaling in Drosophila. The regulation of signaling specificity remains largely obscure. We show that Fz1 and Fz2 have different subcellular localizations in imaginal disc epithelia, with Fz1 localizing preferentially to apical junctional complexes, and Fz2 being evenly distributed basolaterally. The subcellular localization difference directly contributes to the signaling specificity outcome. Whereas apical localization favors Fz/PCP signaling, it interferes with canonical Wnt/beta-catenin signaling. Receptor localization is mediated by sequences in the cytoplasmic tail of Fz2 that appear to block apical accumulation. Based on these data, we propose that subcellular Fz localization, through the association with other membrane proteins, is a critical aspect in regulating the signaling specificity within the Wnt/Fz signaling pathways.

  13. Essential role of TGF-beta/Smad pathway on statin dependent vascular smooth muscle cell regulation.

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    Juan Rodríguez-Vita

    Full Text Available BACKGROUND: The 3-hydroxy-3-methylglutaryl CoA reductase inhibitors (also called statins exert proven beneficial effects on cardiovascular diseases. Recent data suggest a protective role for Transforming Growth Factor-beta (TGF-beta in atherosclerosis by regulating the balance between inflammation and extracellular matrix accumulation. However, there are no studies about the effect of statins on TGF-beta/Smad pathway in atherosclerosis and vascular cells. METHODOLOGY: In cultured vascular smooth muscle cells (VSMCs statins enhanced Smad pathway activation caused by TGF-beta. In addition, statins upregulated TGF-beta receptor type II (TRII, and increased TGF-beta synthesis and TGF-beta/Smad-dependent actions. In this sense, statins, through Smad activation, render VSMCs more susceptible to TGF-beta induced apoptosis and increased TGF-beta-mediated ECM production. It is well documented that high doses of statins induce apoptosis in cultured VSMC in the presence of serum; however the precise mechanism of this effect remains to be elucidated. We have found that statins-induced apoptosis was mediated by TGF-beta/Smad pathway. Finally, we have described that RhoA inhibition is a common intracellular mechanisms involved in statins effects. The in vivo relevance of these findings was assessed in an experimental model of atherosclerosis in apolipoprotein E deficient mice: Treatment with Atorvastatin increased Smad3 phosphorylation and TRII overexpression, associated to elevated ECM deposition in the VSMCs within atheroma plaques, while apoptosis was not detected. CONCLUSIONS: Statins enhance TGF-beta/Smad pathway, regulating ligand levels, receptor, main signaling pathway and cellular responses of VSMC, including apoptosis and ECM accumulation. Our findings show that TGF-beta/Smad pathway is essential for statins-dependent actions in VSMCs.

  14. Deubiquitylating enzyme USP9x regulates hippo pathway activity by controlling angiomotin protein turnover

    DEFF Research Database (Denmark)

    Nguyen, Thanh Hung; Andrejeva, Diana; Gupta, Rajat;

    2016-01-01

    The Hippo pathway has been identified as a key barrier for tumorigenesis, acting through downregulation of YAP/TAZ activity. Elevated YAP/TAZ activity has been documented in many human cancers. Ubiquitylation has been shown to play a key role in regulating YAP/TAZ activity through downregulation....../TAZ activity. We demonstrate that USPx regulates ubiquitin-mediated turnover of the YAP inhibitor, Angiomotin. USP9x acts to deubiquitylate Angiomotin at lysine 496, resulting in stabilization of Angiomotin and lower YAP/TAZ activity. USP9x mRNA levels were reduced in several cancers. Clinically, USP9x m...

  15. Static compression regulates OPG expression in periodontal ligament cells via the CAMK II pathway

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    YI Jianru

    2015-12-01

    Full Text Available ABSTRACT Objective This study aimed to investigate the potential role of CAMK II pathway in the compression-regulated OPG expression in periodontal ligament cells (PDLCs. Material and Methods The PDL tissue model was developed by 3-D culturing human PDLCs in a thin sheet of poly lactic-co-glycolic acid (PLGA scaffolds, which was subjected to static compression of 25 g/cm2 for 3, 6 and 12 h, with or without treatment of KN-93. After that, the expression of OPG, RANKL and NFATC2 was investigated through real-time PCR and western blot analysis. Results After static compression, the NFATC2 and RANKL expression was significantly up-regulated, while partially suppressed by KN-93 for 6 and 12 h respectively. The OPG expression was significantly down-regulated by compression in 3 h, started to elevate in 6 h, and significantly up-regulated in 12 h. The up-regulation after 12 h was significantly suppressed by KN-93. Conclusions Long-term static compression increases OPG expression in PDLCs, at least partially, via the CAMK II pathway.

  16. A systematic screen reveals MicroRNA clusters that significantly regulate four major signaling pathways.

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    Lindsey E Becker

    Full Text Available MicroRNAs (miRNAs are encoded in the genome as individual miRNA genes or as gene clusters transcribed as polycistronic units. About 50% of all miRNAs are estimated to be co-expressed with neighboring miRNAs. Recent studies have begun to illuminate the importance of the clustering of miRNAs from an evolutionary, as well as a functional standpoint. Many miRNA clusters coordinately regulate multiple members of cellular signaling pathways or protein interaction networks. This cooperative method of targeting could produce effects on an overall process that are much more dramatic than the smaller effects often associated with regulation by an individual miRNA. In this study, we screened 366 human miRNA minigenes to determine their effects on the major signaling pathways culminating in AP-1, NF-κB, c-Myc, or p53 transcriptional activity. By stratifying these data into miRNA clusters, this systematic screen provides experimental evidence for the combined effects of clustered miRNAs on these signaling pathways. We also verify p53 as a direct target of miR-200a. This study is the first to provide a panoramic view of miRNA clusters' effects on cellular pathways.

  17. Regulation of GIRK channel deactivation by Galpha(q) and Galpha(i/o) pathways.

    Science.gov (United States)

    Mark, M D; Ruppersberg, J P; Herlitze, S

    2000-09-01

    G protein regulated inward rectifying potassium channels (GIRKs) are activated by G protein coupled receptors (GPCRs) via the G protein betagamma subunits. However, little is known about the effects of different GPCRs on the deactivation kinetics of transmitter-mediated GIRK currents. In the present study we investigated the influence of different GPCRs in the presence and absence of RGS proteins on the deactivation kinetics of GIRK channels by coexpressing the recombinant protein subunits in Xenopus oocytes. The stimulation of both G(i/o)- and G(q)-coupled pathways accelerated GIRK deactivation. GIRK currents deactivated faster upon stimulation of G(i/o)- and G(q)-coupled pathways by P(2)Y(2) receptors (P(2)Y(2)Rs) than upon activation of the G(i/o)-coupled pathway alone via muscarinic acetylcholine receptor M2 (M(2) mAChRs). This acceleration was found to be dependent on phospholipase C (PLC) and protein kinase C (PKC) activities and intracellular calcium. With the assumption that RGS2 has a higher affinity for Galpha(q) than Galpha(i/o), we demonstrated that the deactivation kinetics of GIRK channels can be differentially regulated by the relative amount of RGS proteins. These data indicate that transmitter-mediated deactivation of GIRK currents is modulated by crosstalk between G(i/o)- and G(q)-coupled pathways.

  18. Hypertensive stretch regulates endothelial exocytosis of Weibel-Palade bodies through VEGF receptor 2 signaling pathways.

    Science.gov (United States)

    Xiong, Yan; Hu, Zhenqian; Han, Xiaofan; Jiang, Beibei; Zhang, Rongli; Zhang, Xiaoyu; Lu, Yao; Geng, Chenyang; Li, Wei; He, Yulong; Huo, Yingqing; Shibuya, Masabumi; Luo, Jincai

    2013-06-01

    Regulated endothelial exocytosis of Weibel-Palade bodies (WPBs), the first stage in leukocyte trafficking, plays a pivotal role in inflammation and injury. Acute mechanical stretch has been closely associated with vascular inflammation, although the precise mechanism is unknown. Here, we show that hypertensive stretch regulates the exocytosis of WPBs of endothelial cells (ECs) through VEGF receptor 2 (VEGFR2) signaling pathways. Stretch triggers a rapid release (within minutes) of von Willebrand factor and interleukin-8 from WPBs in cultured human ECs, promoting the interaction between leukocytes and ECs through the translocation of P-selectin to the cell membrane. We further show that hypertensive stretch significantly induces P-selectin translocation of intact ECs and enhances leukocyte adhesion both ex vivo and in vivo. Stretch-induced endothelial exocytosis is mediated via a VEGFR2/PLCγ1/calcium pathway. Interestingly, stretch also induces a negative feedback via a VEGFR2/Akt/nitric oxide pathway. Such dual effects are confirmed using pharmacological and genetic approaches in carotid artery segments, as well as in acute hypertensive mouse models. These studies reveal mechanical stretch as a potent agonist for endothelial exocytosis, which is modulated by VEGFR2 signaling. Thus, VEGFR2 signaling pathways may represent novel therapeutic targets in limiting hypertensive stretch-related inflammation.

  19. Hedgehog signaling pathway regulated the target genes for adipogenesis in silkworm Bombyx mori.

    Science.gov (United States)

    Liang, Shuang; Chen, Rui-Ting; Zhang, Deng-Pan; Xin, Hu-Hu; Lu, Yan; Wang, Mei-Xian; Miao, Yun-Gen

    2015-10-01

    Hedgehog (Hh) signals regulate invertebrate and vertebrate development, yet the role of the pathway in adipose development remains poorly understood. In this report, we found that Hh pathway components are expressed in the fat body of silkworm larvae. Functional analysis of these components in a BmN cell line model revealed that activation of the Hh gene stimulated transcription of Hh pathway components, but inhibited the expression of the adipose marker gene AP2. Conversely, specific RNA interference-mediated knockdown of Hh resulted in increased AP2 expression. This further showed the regulation of Hh signal on the adipose marker gene. In silkworm larval models, enhanced adipocyte differentiation and an increase in adipocyte cell size were observed in silkworms that had been treated with a specific Hh signaling pathway antagonist, cyclopamine. The fat-body-specific Hh blockade tests were consistent with Hh signaling inhibiting silkworm adipogenesis. Our results indicate that the role of Hh signaling in inhibiting fat formation is conserved in vertebrates and invertebrates.

  20. Cdk9 T-loop phosphorylation is regulated by the calcium signaling pathway.

    Science.gov (United States)

    Ramakrishnan, Rajesh; Rice, Andrew P

    2012-02-01

    Eukaryotic RNA polymerase II transcriptional elongation is a tightly regulated process and is dependent upon positive transcription elongation factor-b (P-TEFb). The core P-TEFb complex is composed of Cdk9 and Cyclin T and is essential for the expression of most protein coding genes. Cdk9 kinase function is dependent upon phosphorylation of Thr186 in its T-loop. In this study, we examined kinases and signaling pathways that influence Cdk9 T-loop phosphorylation. Using an RNAi screen in HeLa cells, we found that Cdk9 T-loop phosphorylation is regulated by Ca(2+)/calmodulin-dependent kinase 1D (CaMK1D). Using small molecules inhibitors in HeLa cells and primary CD4(+) T lymphocytes, we found that the Ca(2+) signaling pathway is required for Cdk9 T-loop phosphorylation. Inhibition of Ca(2+) signaling led to dephosphorylation of Thr186 on Cdk9. In reporter plasmid assays, inhibition of the Ca(2+) signaling pathway repressed the PCNA promoter and HIV-1 Tat transactivation of the HIV-1 LTR, but not HTLV-1 Tax transactivation of the HTLV-1 LTR, suggesting that perturbation of the Ca(2+) pathway and reduction of Cdk9 T-loop phosphorylation inhibits transcription units that have a rigorous requirement for P-TEFb function.

  1. Genome-wide analysis of a Wnt1-regulated transcriptional network implicates neurodegenerative pathways.

    Science.gov (United States)

    Wexler, Eric M; Rosen, Ezra; Lu, Daning; Osborn, Gregory E; Martin, Elizabeth; Raybould, Helen; Geschwind, Daniel H

    2011-10-04

    Wnt proteins are critical to mammalian brain development and function. The canonical Wnt signaling pathway involves the stabilization and nuclear translocation of β-catenin; however, Wnt also signals through alternative, noncanonical pathways. To gain a systems-level, genome-wide view of Wnt signaling, we analyzed Wnt1-stimulated changes in gene expression by transcriptional microarray analysis in cultured human neural progenitor (hNP) cells at multiple time points over a 72-hour time course. We observed a widespread oscillatory-like pattern of changes in gene expression, involving components of both the canonical and the noncanonical Wnt signaling pathways. A higher-order, systems-level analysis that combined independent component analysis, waveform analysis, and mutual information-based network construction revealed effects on pathways related to cell death and neurodegenerative disease. Wnt effectors were tightly clustered with presenilin1 (PSEN1) and granulin (GRN), which cause dominantly inherited forms of Alzheimer's disease and frontotemporal dementia (FTD), respectively. We further explored a potential link between Wnt1 and GRN and found that Wnt1 decreased GRN expression by hNPs. Conversely, GRN knockdown increased WNT1 expression, demonstrating that Wnt and GRN reciprocally regulate each other. Finally, we provided in vivo validation of the in vitro findings by analyzing gene expression data from individuals with FTD. These unbiased and genome-wide analyses provide evidence for a connection between Wnt signaling and the transcriptional regulation of neurodegenerative disease genes.

  2. The hippo pathway promotes Notch signaling in regulation of cell differentiation, proliferation, and oocyte polarity.

    Directory of Open Access Journals (Sweden)

    Jianzhong Yu

    Full Text Available Specification of the anterior-posterior axis in Drosophila oocytes requires proper communication between the germ-line cells and the somatically derived follicular epithelial cells. Multiple signaling pathways, including Notch, contribute to oocyte polarity formation by controlling the temporal and spatial pattern of follicle cell differentiation and proliferation. Here we show that the newly identified Hippo tumor-suppressor pathway plays a crucial role in the posterior follicle cells in the regulation of oocyte polarity. Disruption of the Hippo pathway, including major components Hippo, Salvador, and Warts, results in aberrant follicle-cell differentiation and proliferation and dramatic disruption of the oocyte anterior-posterior axis. These phenotypes are related to defective Notch signaling in follicle cells, because misexpression of a constitutively active form of Notch alleviates the oocyte polarity defects. We also find that follicle cells defective in Hippo signaling accumulate the Notch receptor and display defects in endocytosis markers. Our findings suggest that the interaction between Hippo and classic developmental pathways such as Notch is critical to spatial and temporal regulation of differentiation and proliferation and is essential for development of the body axes in Drosophila.

  3. Hypertensive stretch regulates endothelial exocytosis of Weibel-Palade bodies through VEGF receptor 2 signaling pathways

    Institute of Scientific and Technical Information of China (English)

    Yan Xiong; Zhenqian Hu; Xiaofan Han; Beibei Jiang; Rongli Zhang; Xiaoyu Zhang; Yao Lu

    2013-01-01

    Regulated endothelial exocytosis of Weibel-Palade bodies (WPBs),the first stage in leukocyte trafficking,plays a pivotal role in inflammation and injury.Acute mechanical stretch has been closely associated with vascular inflammation,although the precise mechanism is unknown.Here,we show that hypertensive stretch regulates the exocytosis of WPBs of endothelial ceils (ECs) through VEGF receptor 2 (VEGFR2) signaling pathways.Stretch triggers a rapid release (within minutes) of von Willebrand factor and interleukin-8 from WPBs in cultured human ECs,promoting the interaction between leukocytes and ECs through the translocation of P-selectin to the cell membrane.We further show that hypertensive stretch significantly induces P-selectin translocation of intact ECs and enhances leukocyte adhesion both ex vivo and in vivo.Stretch-induced endothelial exocytosis is mediated via a VEGFR2/PLCy1/calcium pathway.Interestingly,stretch also induces a negative feedback via a VEGFR2/Akt/nitric oxide pathway.Such dual effects are confirmed using pharmacological and genetic approaches in carotid artery segments,as well as in acute hypertensive mouse models.These studies reveal mechanical stretch as a potent agonist for endothelial exocytosis,which is modulated by VEGFR2 signaling.Thus,VEGFR2 signaling pathways may represent novel therapeutic targets in limiting hypertensive stretch-related inflammation.

  4. ERK5 pathway regulates the phosphorylation of tumour suppressor hDlg during mitosis

    Energy Technology Data Exchange (ETDEWEB)

    Inesta-Vaquera, Francisco A. [Departamento de Inmunologia y Oncologia, Centro Nacional de Biotecnologia-CSIC, Campus de Cantoblanco-UAM, 28049 Madrid (Spain); Campbell, David G.; Arthur, J. Simon C. [MRC Protein Phosphorylation Unit, Sir James Black Building, School of Life Sciences, University of Dundee, Dundee DD1 5EH (United Kingdom); Cuenda, Ana, E-mail: acuenda@cnb.csic.es [Departamento de Inmunologia y Oncologia, Centro Nacional de Biotecnologia-CSIC, Campus de Cantoblanco-UAM, 28049 Madrid (Spain)

    2010-08-13

    Research highlights: {yields} hDlg is phosphorylated during mitosis in multiple residues. {yields} Prospho-hDlg is excluded from the midbody during mitosis. {yields} hDlg is not phosphorylated by p38{gamma} or JNK1/2 during mitosis. {yields} ERK5 pathway mediates hDlg phosphorylation in mitosis. -- Abstract: Human disc-large (hDlg) is a scaffold protein critical for the maintenance of cell polarity and adhesion. hDlg is thought to be a tumour suppressor that regulates the cell cycle and proliferation. However, the mechanism and pathways involved in hDlg regulation during these processes is still unclear. Here we report that hDlg is phosphorylated during mitosis, and we establish the identity of at least three residues phosphorylated in hDlg; some are previously unreported. Phosphorylation affects hDlg localisation excluding it from the contact point between the two daughter cells. Our results reveal a previously unreported pathway for hDlg phosphorylation in mitosis and show that ERK5 pathway mediates hDlg cell cycle dependent phosphorylation. This is likely to have important implications in the correct timely mitotic entry and mitosis progression.

  5. Mechanisms of JAK/STAT pathway negative regulation by the short coreceptor Eye Transformer/Latran.

    Science.gov (United States)

    Fisher, Katherine H; Stec, Wojciech; Brown, Stephen; Zeidler, Martin P

    2016-02-01

    Transmembrane receptors interact with extracellular ligands to transduce intracellular signaling cascades, modulate target gene expression, and regulate processes such as proliferation, apoptosis, differentiation, and homeostasis. As a consequence, aberrant signaling events often underlie human disease. Whereas the vertebrate JAK/STAT signaling cascade is transduced via multiple receptor combinations, the Drosophila pathway has only one full-length signaling receptor, Domeless (Dome), and a single negatively acting receptor, Eye Transformer/Latran (Et/Lat). Here we investigate the molecular mechanisms underlying Et/Lat activity. We demonstrate that Et/Lat negatively regulates the JAK/STAT pathway activity and can bind to Dome, thus reducing Dome:Dome homodimerization by creating signaling-incompetent Dome:Et/Lat heterodimers. Surprisingly, we find that Et/Lat is able to bind to both JAK and STAT92E but, despite the presence of putative cytokine-binding motifs, does not detectably interact with pathway ligands. We find that Et/Lat is trafficked through the endocytic machinery for lysosomal degradation but at a much slower rate than Dome, a difference that may enhance its ability to sequester Dome into signaling-incompetent complexes. Our data offer new insights into the molecular mechanism and regulation of Et/Lat in Drosophila that may inform our understanding of how short receptors function in other organisms.

  6. HIF-1α pathway: role, regulation and intervention for cancer therapy

    Directory of Open Access Journals (Sweden)

    Georgina N. Masoud

    2015-09-01

    Full Text Available Hypoxia-inducible factor-1 (HIF-1 has been recognized as an important cancer drug target. Many recent studies have provided convincing evidences of strong correlation between elevated levels of HIF-1 and tumor metastasis, angiogenesis, poor patient prognosis as well as tumor resistance therapy. It was found that hypoxia (low O2 levels is a common character in many types of solid tumors. As an adaptive response to hypoxic stress, hypoxic tumor cells activate several survival pathways to carry out their essential biological processes in different ways compared with normal cells. Recent advances in cancer biology at the cellular and molecular levels highlighted the HIF-1α pathway as a crucial survival pathway for which novel strategies of cancer therapy could be developed. However, targeting the HIF-1α pathway has been a challenging but promising progresses have been made in the past twenty years. This review summarizes the role and regulation of the HIF-1α in cancer, and recent therapeutic approaches targeting this important pathway.

  7. Transcriptional regulators in the Hippo signaling pathway control organ growth in Xenopus tadpole tail regeneration.

    Science.gov (United States)

    Hayashi, Shinichi; Ochi, Haruki; Ogino, Hajime; Kawasumi, Aiko; Kamei, Yasuhiro; Tamura, Koji; Yokoyama, Hitoshi

    2014-12-01

    The size and shape of tissues are tightly controlled by synchronized processes among cells and tissues to produce an integrated organ. The Hippo signaling pathway controls both cell proliferation and apoptosis by dual signal-transduction states regulated through a repressive kinase cascade. Yap1 and Tead, transcriptional regulators that act downstream of the Hippo signaling kinase cascade, have essential roles in regulating cell proliferation. In amphibian limb or tail regeneration, the local tissue outgrowth terminates when the correct size is reached, suggesting that organ size is strictly controlled during epimorphic organ-level regeneration. We recently demonstrated that Yap1 is required for the regeneration of Xenopus tadpole limb buds (Hayashi et al., 2014, Dev. Biol. 388, 57-67), but the molecular link between the Hippo pathway and organ size control in vertebrate epimorphic regeneration is not fully understood. To examine the requirement of Hippo pathway transcriptional regulators in epimorphic regeneration, including organ size control, we inhibited these regulators during Xenopus tadpole tail regeneration by overexpressing a dominant-negative form of Yap (dnYap) or Tead4 (dnTead4) under a heat-shock promoter in transgenic animal lines. Each inhibition resulted in regeneration defects accompanied by reduced cell mitosis and increased apoptosis. Single-cell gene manipulation experiments indicated that Tead4 cell-autonomously regulates the survival of neural progenitor cells in the regenerating tail. In amphibians, amputation at the proximal level of the tail (deep amputation) results in faster regeneration than that at the distal level (shallow amputation), to restore the original-sized tail with similar timing. However, dnTead4 overexpression abolished the position-dependent differential growth rate of tail regeneration. These results suggest that the transcriptional regulators in the Hippo pathway, Tead4 and Yap1, are required for general vertebrate

  8. Leptin differentially regulates NPY secretion in hypothalamic cell lines through distinct intracellular signal transduction pathways.

    Science.gov (United States)

    Dhillon, Sandeep S; Belsham, Denise D

    2011-04-11

    Leptin acts as a key peripheral hormone in distinct neurons in the hypothalamus to modulate both reproductive function and energy homeostasis. The control of neuropeptide Y (NPY) secretion is an example of a process that can be differentially regulated by leptin. In order to further understand these distinct modulatory effects, we have used immortalized, neuronal hypothalamic cell lines expressing NPY, mHypoE-38 and mHypoE-46. We found that these cell lines express the endogenous leptin receptor, ObRb, and secrete detectable levels of NPY. We exposed the neurons to 100nM leptin for 1h and determined that the basal levels of NPY in the cell lines were differentially regulated: NPY secretion was inhibited in mHypoE-46 neurons, whereas NPY secretion was induced in the mHypoE-38 neurons. In order to determine the mechanisms involved in the divergent regulation of NPY release, we analyzed the activity of a number of signaling components using phospho-specific antibodies directed towards specific proteins in the MAP kinase, PI3K, and AMPK pathways, among others. We found that leptin activated a different combination of second messengers in each cell line. Importantly, we could link the regulation of NPY secretion to different signaling pathways, AMPK in the mHypoE-46 and both MAPK and PI3K in the mHypoE-38 neurons. This is the first demonstration that leptin can specifically regulate individual NPY neuron secretory responses through distinct signaling pathways.

  9. Sugar Allocation to Metabolic Pathways is Tightly Regulated and Affects the Virulence of Streptococcus mutans

    Science.gov (United States)

    Kawada-Matsuo, Miki; Oogai, Yuichi; Komatsuzawa, Hitoshi

    2016-01-01

    Bacteria take up and metabolize sugar as a carbohydrate source for survival. Most bacteria can utilize many sugars, including glucose, sucrose, and galactose, as well as amino sugars, such as glucosamine and N-acetylglucosamine. After entering the cytoplasm, the sugars are mainly allocated to the glycolysis pathway (energy production) and to various bacterial component biosynthesis pathways, including the cell wall, nucleic acids and amino acids. Sugars are also utilized to produce several virulence factors, such as capsule and lipoteichoic acid. Glutamine-fructose-6-phosphate aminotransferase (GlmS) and glucosamine-6-phosphate deaminase (NagB) have crucial roles in sugar distribution to the glycolysis pathway and to cell wall biosynthesis. In Streptococcus mutans, a cariogenic pathogen, the expression levels of glmS and nagB are coordinately regulated in response to the presence or absence of amino sugars. In addition, the disruption of this regulation affects the virulence of S. mutans. The expression of nagB and glmS is regulated by NagR in S. mutans, but the precise mechanism underlying glmS regulation is not clear. In Staphylococcus aureus and Bacillus subtilis, the mRNA of glmS has ribozyme activity and undergoes self-degradation at the mRNA level. However, there is no ribozyme activity region on glmS mRNA in S. mutans. In this review article, we summarize the sugar distribution, particularly the coordinated regulation of GlmS and NagB expression, and its relationship with the virulence of S. mutans. PMID:28036052

  10. Stress-induced nuclear RNA degradation pathways regulate yeast bromodomain factor 2 to promote cell survival.

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    Kevin Roy

    2014-09-01

    Full Text Available Bromodomain proteins are key regulators of gene expression. How the levels of these factors are regulated in specific environmental conditions is unknown. Previous work has established that expression of yeast Bromodomain factor 2 (BDF2 is limited by spliceosome-mediated decay (SMD. Here we show that BDF2 is subject to an additional layer of post-transcriptional control through RNase III-mediated decay (RMD. We found that the yeast RNase III Rnt1p cleaves a stem-loop structure within the BDF2 mRNA to down-regulate its expression. However, these two nuclear RNA degradation pathways play distinct roles in the regulation of BDF2 expression, as we show that the RMD and SMD pathways of the BDF2 mRNA are differentially activated or repressed in specific environmental conditions. RMD is hyper-activated by salt stress and repressed by hydroxyurea-induced DNA damage while SMD is inactivated by salt stress and predominates during DNA damage. Mutations of cis-acting signals that control SMD and RMD rescue numerous growth defects of cells lacking Bdf1p, and show that SMD plays an important role in the DNA damage response. These results demonstrate that specific environmental conditions modulate nuclear RNA degradation pathways to control BDF2 expression and Bdf2p-mediated gene regulation. Moreover, these results show that precise dosage of Bromodomain factors is essential for cell survival in specific environmental conditions, emphasizing their importance for controlling chromatin structure and gene expression in response to environmental stress.

  11. Deubiquitinating enzyme regulation of the p53 pathway: A lesson from Otub1

    Institute of Scientific and Technical Information of China (English)

    Xiao-Xin; Sun; Mu-Shui; Dai

    2014-01-01

    Deubiquitination has emerged as an important mechanism of p53 regulation. A number of deubiquitinating enzymes(DUBs) from the ubiquitin-specific protease family have been shown to regulate the p53-MDM2-MDMX networks. We recently reported that Otub1, a DUB from the OTU-domain containing protease family, is a novel p53 regulator. Interestingly, Otub1 abrogates p53 ubiquitination and stabilizes and activates p53 in cells independently of its deubiquitinating enzyme activity. Instead, it does so by inhibiting the MDM2 cognate ubiquitin-conjugating enzyme(E2) UbcH5. Otub1 also regulates other biological signaling through this non-canonical mechanism, suppression of E2, including the inhibition of DNA-damage-induced chromatin ubiquitination. Thus, Otub1 evolves as a unique DUB that mainly suppresses E2 to regulate substrates. Here we review the current progress made towards the understanding of the complex regulation of the p53 tumor suppressor pathway by DUBs, the biological function of Otub1 including its positive regulation of p53, and the mechanistic insights into how Otub1 suppresses E2.

  12. The associated regulators and signal pathway in rILl-16/CD4 mediated growth regulation in Jurkat cells

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    IL-16 is a ligand and chemotactic factor for CD4+ T cells. IL-16 inhibits the CD3 mediated lymphocyteactivation and proliferation. The effects of IL-16 on the target cells are dependent on the cell type, thepresence of co-activators etc. To understand the regulation function and mechanism of IL-16 on targetcells, we used a 130 a.a. recombinant IL-16 to study its effects on the growth of Jurkat T leukemia cellsin vitro. We found that the rIL-16 stimulated the proliferation of Jurkat cells at low dose (10-9M), butinhibited the growth of the cells at higher concentration (10-5M). Results showed that 10-5 M of rIL-16treatment induced an enhanced apoptosis in Jurkat cells. The treatment blocked the expression of FasL, butup-regulated the c-myc and Bid expression in the cells. Pre-treatment of PKC inhibitor or MEK1 inhibitormarkedly increased or decreased the rIL-16 induced growth-inhibiting effects on Jurkat cells, respectively.The results suggested that the rIL-16 might be a regulator for the growth or apoptosis of Jurkat cells ata dose-dependent manner. The growth-inhibiting effects of rIL-16 might be Fas/FasL independent, but,associated with the activation of PKC, up-regulated expression of c-Myc and Bid, and the participation ofthe ERK signal pathway in Jurkat cells.

  13. WDR26 in Advanced Breast Cancer: A Novel Regulator of the P13K/AKT Pathway

    Science.gov (United States)

    2015-10-01

    AWARD NUMBER: W81XWH-14-1-0539 TITLE: WDR26 in Advanced Breast Cancer : A Novel Regulator of the P13K/AKT Pathway PRINCIPAL INVESTIGATOR...5a. CONTRACT NUMBER WDR26 in Advanced Breast Cancer : A Novel Regulator of the P13K/AKT Pathway 5b. GRANT NUMBER W81XWH-14-1-0539 5c. PROGRAM...SUPPLEMENTARY NOTES 14. ABSTRACT The PI3K/AKT pathway is one of the most deregulated pathways in breast cancers (>70%), and a major contributor to tumor

  14. The silent information regulator 1 (Sirt1) is a positive regulator of the Notch pathway in Drosophila.

    Science.gov (United States)

    Horvath, Matej; Mihajlovic, Zorana; Slaninova, Vera; Perez-Gomez, Raquel; Moshkin, Yuri; Krejci, Alena

    2016-11-15

    The silent information regulator 1 (Sirt1) has been shown to have negative effects on the Notch pathway in several contexts. We bring evidence that Sirt1 has a positive effect on Notch activation in Drosophila, in the context of sensory organ precursor specification and during wing development. The phenotype of Sirt1 mutant resembles weak Notch loss-of-function phenotypes, and genetic interactions of Sirt1 with the components of the Notch pathway also suggest a positive role for Sirt1 in Notch signalling. Sirt1 is necessary for the efficient activation of enhancer of split [E(spl)] genes by Notch in S2N cells. Additionally, the Notch-dependent response of several E(spl) genes is sensitive to metabolic stress caused by 2-deoxy-d-glucose treatment, in a Sirt1-dependent manner. We found Sirt1 associated with several proteins involved in Notch repression as well as activation, including the cofactor exchange factor Ebi (TBL1), the RLAF/LAF histone chaperone complex and the Tip60 acetylation complex. Moreover, Sirt1 participates in the deacetylation of the CSL transcription factor Suppressor of Hairless. The role of Sirt1 in Notch signalling is, therefore, more complex than previously recognized, and its diverse effects may be explained by a plethora of Sirt1 substrates involved in the regulation of Notch signalling.

  15. Time-course regulation of survival pathways by epicatechin on HepG2 cells.

    Science.gov (United States)

    Granado-Serrano, Ana Belén; Angeles Martín, María; Goya, Luis; Bravo, Laura; Ramos, Sonia

    2009-02-01

    Polyphenols, such as epicatechin, have been reported to exhibit a wide range of biological activities. The objective of the present study was to investigate the time-dependent regulation by epicatechin of survival/proliferation pathways in HepG2 cells. Treatment of HepG2 cells with 10 micromol/L epicatechin did not result in any cell damage up to 18 h, as evaluated by the lactate dehydrogenase assay. Moreover, the enhanced cell death evoked by an oxidative stress induced with tert-butyl hydroperoxide was prevented in the cells pretreated 4 or 18 h with epicatechin. Epicatechin-induced survival was a rapid event that was accompanied by early and sustained activation of major survival signaling proteins, such as AKT/phosphatidylinositol 3-kinase and extracellular-regulated kinase (activated from 5 min to 18 h), as well as protein kinase C (PKC)-alpha (30 min to 18 h), in concert with unaltered c-jun N-amino terminal kinase levels and early inactivation of key death-related signals like PKC-delta (5 min to 18 h). Additionally, reactive oxygen species generation was transiently reduced when cells were treated with 10 micromol/L epicatechin (15-240 min). These data suggest that epicatechin induces cellular survival through a tight regulation of survival/proliferation pathways that requires the integration of different signals and persists over time, the ultimate effect on HepG2 cells being regulated by the balance among these signals.

  16. Ubiquitin-Specific Peptidase USP22 Negatively Regulates the STAT Signaling Pathway by Deubiquitinating SIRT1

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    Ning Ao

    2014-06-01

    Full Text Available Background/Aims: The ubiquitin-specific peptidase USP22 mediates various cellular and organismal processes, such as cell growth, apoptosis, and tumor malignancy. However, the molecular mechanisms that regulate USP22 activity remain poorly understood. Here we identify STAT3 as a new USP22 interactor. Methods:· We used western blotting and RT-PCR to measure key protein, acetylated STAT3, and mRNA levels in HEK293 and colorectal cancer cell lines transfected with expression plasmids or specific siRNAs. Co-immunoprecipitation was used to demonstrate protein-protein interaction and protein complex composition. Results: USP22 overexpression down-regulated STAT3 acetylation by deubiquitinating SIRT1. The three proteins were found to be present in a single protein complex. SiRNA-mediated depletion of endogenous USP22 resulted in SIRT1 destabilization and elevated STAT3 acetylation. Consistent with this finding, USP22 also down-regulated the expression of two known STAT3 target genes, MMP9 and TWIST. Conclusion: We show that USP22 is a new regulator of the SIRT1-STAT3 signaling pathway and report a new mechanistic explanation for cross talk between USP22 and the SIRT1-STAT pathways.

  17. Rare genomic variants link bipolar disorder to CREB regulated intracellular signaling pathways

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    Berit eKerner

    2013-11-01

    Full Text Available Bipolar disorder is a common, complex, and severe psychiatric disorder with cyclical disturbances of mood and a high suicide rate. Here, we describe a family with four siblings, three affected females and one unaffected male. The disease course was characterized by early-onset bipolar disorder and co-morbid anxiety spectrum disorders that followed the onset of bipolar disorder. Genetic risk factors were suggested by the early onset of the disease, the severe disease course, including multiple suicide attempts, and lack of adverse prenatal or early life events. In particular, drug and alcohol abuse did not contribute to the disease onset. Exome sequencing identified very rare, heterozygous, and likely protein-damaging variants in eight brain-expressed genes: IQUB, JMJD1C, GADD45A, GOLGB1, PLSCR5, VRK2, MESDC2, and FGGY. The variants were shared among all three affected family members but absent in the unaffected sibling and in more than 200 controls. The genes encode proteins with significant regulatory roles in the ERK/MAPK and CREB-regulated intracellular signaling pathways. These pathways are central to neuronal and synaptic plasticity, cognition, affect regulation and response to chronic stress. In addition, proteins in these pathways are the target of commonly used mood stabilizing drugs, such as tricyclic antidepressants, lithium and valproic acid. The combination of multiple rare, damaging mutations in these central pathways could lead to reduced resilience and increased vulnerability to stressful life events. Our results support a new model for psychiatric disorders, in which multiple rare, damaging mutations in genes functionally related to a common signaling pathway contribute to the manifestation of bipolar disorder.

  18. Phosphatidylinositol 3-kinase pathway regulates sperm viability but not capacitation on boar spermatozoa.

    Science.gov (United States)

    Aparicio, I M; Bragado, M J; Gil, M C; Garcia-Herreros, M; Gonzalez-Fernandez, L; Tapia, J A; Garcia-Marin, L J

    2007-08-01

    Phosphatidylinositol 3-kinase (PI3-K) plays an important role in cell survival in somatic cells and recent data pointed out a role for this kinase in sperm capacitation and acrosome reaction (AR). This study was undertaken to evaluate the role of PI3-K pathway on porcine spermatozoa capacitation, AR, and viability using two unrelated PI3-K inhibitors, LY294002 and wortmannin. In boar spermatozoa, we have identified the presence of PDK1, PKB/Akt, and PTEN, three of the main key components of the PI3-K pathway. Incubation of boar sperm in a capacitating medium (TCM) caused a significant increase in the percentage of capacitated (25 +/- 2 to 34 +/- 1% P sperm in basal medium (TBM). Inhibition of PI3-K did affect neither the capacitation status nor AR nor protein p32 tyrosine phosphorylation of boar spermatozoa incubated in TBM or TCM. Boar sperm viability in TBM was significantly decreased by 40 and 20% after pretreatment with LY294002 or wortmannin, respectively. Similar results were observed after incubation of boar spermatozoa in TCM. Treatment of boar spermatozoa with the analog of cAMP, 8Br-cAMP significantly prevented the reduction on sperm viability. Our results provide evidence for an important role of the PI3-K pathway in the regulation of boar sperm viability and suggests that other signaling pathways different from PI3-K must be activated downstream of cAMP to contribute to regulation of sperm viability. Finally, in our conditions the PI3-K pathway seems not related with boar sperm capacitation or AR.

  19. Dishevelled genes mediate a conserved mammalian PCP pathway to regulate convergent extension during neurulation.

    Science.gov (United States)

    Wang, Jianbo; Hamblet, Natasha S; Mark, Sharayne; Dickinson, Mary E; Brinkman, Brendan C; Segil, Neil; Fraser, Scott E; Chen, Ping; Wallingford, John B; Wynshaw-Boris, Anthony

    2006-05-01

    The planar cell polarity (PCP) pathway is conserved throughout evolution, but it mediates distinct developmental processes. In Drosophila, members of the PCP pathway localize in a polarized fashion to specify the cellular polarity within the plane of the epithelium, perpendicular to the apicobasal axis of the cell. In Xenopus and zebrafish, several homologs of the components of the fly PCP pathway control convergent extension. We have shown previously that mammalian PCP homologs regulate both cell polarity and polarized extension in the cochlea in the mouse. Here we show, using mice with null mutations in two mammalian Dishevelled homologs, Dvl1 and Dvl2, that during neurulation a homologous mammalian PCP pathway regulates concomitant lengthening and narrowing of the neural plate, a morphogenetic process defined as convergent extension. Dvl2 genetically interacts with Loop-tail, a point mutation in the mammalian PCP gene Vangl2, during neurulation. By generating Dvl2 BAC (bacterial artificial chromosome) transgenes and introducing different domain deletions and a point mutation identical to the dsh1 allele in fly, we further demonstrated a high degree of conservation between Dvl function in mammalian convergent extension and the PCP pathway in fly. In the neuroepithelium of neurulating embryos, Dvl2 shows DEP domain-dependent membrane localization, a pre-requisite for its involvement in convergent extension. Intriguing, the Loop-tail mutation that disrupts both convergent extension in the neuroepithelium and PCP in the cochlea does not disrupt Dvl2 membrane distribution in the neuroepithelium, in contrast to its drastic effect on Dvl2 localization in the cochlea. These results are discussed in light of recent models on PCP and convergent extension.

  20. Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of apolipoprotein E deficient mice

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Hong-Bo, E-mail: xhbzhb@yahoo.com [College of Veterinary Medicine, Hunan Agricultural University, Changsha 410128 (China); Lu, Xiang-Yang; Sun, Zhi-Liang [Hunan Agricultural University, Changsha 410128 (China); Zhang, Heng-Bo [Furong District Red Cross Hospital, Changsha 410126 (China)

    2011-12-15

    Recent studies show that osteopontin (OPN) and its receptor cluster of differentiation 44 (CD44) are two pro-inflammatory cytokines contributing to the development of atherosclerosis. The objective of this study was to explore the inhibitory effect of kaempferol, a naturally occurring flavonoid compound, on atherogenesis and the mechanisms involved. The experiments were performed in aorta and plasma from C57BL/6J control and apolipoprotein E-deficient (ApoE{sup -/-}) mice treated or not with kaempferol (50 or 100 mg/kg, intragastrically) for 4 weeks. Kaempferol treatment decreased atherosclerotic lesion area, improved endothelium-dependent vasorelaxation, and increased the maximal relaxation value concomitantly with decrease in the half-maximum effective concentration, plasma OPN level, aortic OPN expression, and aortic CD44 expression in ApoE{sup -/-} mice. In addition, treatment with kaempferol also significantly decreased reactive oxygen species production in mice aorta. The present results suggest that kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. -- Graphical abstract: Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. Highlights: Black-Right-Pointing-Pointer OPN-CD44 pathway plays a critical role in the development of atherosclerosis. Black-Right-Pointing-Pointer We examine lesion area, OPN and CD44 changes after kaempferol treatment. Black-Right-Pointing-Pointer Kaempferol treatment decreased atherosclerotic lesion area in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol treatment decreased aortic OPN and CD44 expressions in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis.

  1. Pathway-specific regulation revisited: cross-regulation of multiple disparate gene clusters by PAS-LuxR transcriptional regulators.

    Science.gov (United States)

    Vicente, Cláudia M; Payero, Tamara D; Santos-Aberturas, Javier; Barreales, Eva G; de Pedro, Antonio; Aparicio, Jesús F

    2015-06-01

    PAS-LuxR regulators are highly conserved proteins devoted to the control of antifungal production by binding to operators located in given promoters of polyene biosynthetic genes. The canonical operator of PimM, archetype of this class of regulators, has been used here to search for putative targets of orthologous protein PteF in the genome of Streptomyces avermitilis, finding 97 putative operators outside the pentaene filipin gene cluster (pte). The processes putatively affected included genetic information processing; energy, carbohydrate, and lipid metabolism; DNA replication and repair; morphological differentiation; secondary metabolite biosynthesis; and transcriptional regulation, among others. Seventeen of these operators were selected, and their binding to PimM DNA-binding domain was assessed by electrophoretic mobility shift assays. Strikingly, the protein bound all predicted operators suggesting a direct control over targeted processes. As a proof of concept, we studied the biosynthesis of the ATP-synthase inhibitor oligomycin whose gene cluster included two operators. Regulator mutants showed a severe loss of oligomycin production, whereas gene complementation of the mutant restored phenotype, and gene duplication in the wild-type strain boosted oligomycin production. Comparative gene expression analyses in parental and mutant strains by reverse transcription-quantitative polymerase chain reaction of selected olm genes corroborated production results. These results demonstrate that PteF is able to cross-regulate the biosynthesis of two related secondary metabolites, filipin and oligomycin, but might be extended to all the processes indicated above. This study highlights the complexity of the network of interactions in which PAS-LuxR regulators are involved and opens new possibilities for the manipulation of metabolite production in Streptomycetes.

  2. LINGO-1 Regulates Oligodendrocyte Differentiation through the Cytoplasmic Gelsolin Signaling Pathway.

    Science.gov (United States)

    Shao, Zhaohui; Lee, Xinhua; Huang, Guanrong; Sheng, Guoqing; Henderson, Christopher E; Louvard, Daniel; Sohn, Jiho; Pepinsky, Blake; Mi, Sha

    2017-03-22

    Differentiation and maturation of oligodendrocyte progenitor cells (OPCs) involve the assembly and disassembly of actin microfilaments. However, how actin dynamics are regulated during this process remains poorly understood. Leucine-rich repeat and Ig-like domain-containing Nogo receptor interacting protein 1 (LINGO-1) is a negative regulator of OPC differentiation. We discovered that anti-LINGO-1 antibody-promoted OPC differentiation was accompanied by upregulation of cytoplasmic gelsolin (cGSN), an abundant actin-severing protein involved in the depolymerization of actin filaments. Treating rat OPCs with cGSN siRNA reduced OPC differentiation, whereas overexpression of cGSN promoted OPC differentiation in vitro and remyelination in vivo Furthermore, coexpression of cGSN and LINGO-1 blocked the inhibitory effect of LINGO-1. Our study demonstrates that cGSN works downstream of LINGO-1 signaling pathway, which enhances actin dynamics and is essential for OPC morphogenesis and differentiation. This finding may lead to novel therapeutic approaches for the treatment of demyelinating diseases such as multiple sclerosis (MS).SIGNIFICANCE STATEMENT Myelin loss and subsequent axon degeneration contributes to a variety of neurological diseases, such as multiple sclerosis (MS). Understanding the regulation of myelination by oligodendrocytes is therefore critical for developing therapies for the treatment of MS. We previously demonstrated that leucine-rich repeat and Ig-like domain-containing Nogo receptor interacting protein 1 (LINGO-1) is a negative regulator of oligodendrocyte differentiation and that anti-LINGO-1 promotes remyelination in preclinical animal models for MS and in a phase II acute optic neuritis clinical trial (RENEW). The mechanism by which LINGO-1 regulates oligodendrocyte differentiation is unknown. Here, we demonstrate that LINGO-1 regulates oligodendrocyte differentiation and maturation through the cytoplasmic gelsolin signaling pathway, providing new

  3. Identification of DreI as an antiviral factor regulated by RLR signaling pathway.

    Directory of Open Access Journals (Sweden)

    Shun Li

    Full Text Available BACKGROUND: Retinoic acid-inducible gene I (RIG-I-like receptors (RLRs had been demonstrated to prime interferon (IFN response against viral infection via the conserved RLR signaling in fish, and a novel fish-specific gene, the grass carp reovirus (GCRV-induced gene 2 (Gig2, had been suggested to play important role in host antiviral response. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we cloned and characterized zebrafish Gig2 homolog (named Danio rerio Gig2-I, DreI, and revealed its antiviral role and expressional regulation signaling pathway. RT-PCR, Western blot and promoter activity assay indicate that DreI can be induced by poly I:C, spring viremia of carp virus (SVCV and recombinant IFN (rIFN, showing that DreI is a typical ISG. Using the pivotal signaling molecules of RLR pathway, including RIG-I, MDA5 and IRF3 from crucian carp, it is found that DreI expression is regulated by RLR cascade and IRF3 plays an important role in this regulation. Furthermore, promoter mutation assay confirms that the IFN-stimulated regulatory elements (ISRE in the 5' flanking region of DreI is essential for its induction. Finally, overexpression of DreI leads to establish a strong antiviral state against SVCV and Rana grylio virus (RGV infection in EPC (Epithelioma papulosum cyprinid cells. CONCLUSIONS/SIGNIFICANCE: These data indicate that DreI is an antiviral protein, which is regulated by RLR signaling pathway.

  4. Antagonistic cross-regulation between Wnt and Hedgehog signalling pathways controls post-embryonic retinal proliferation.

    Science.gov (United States)

    Borday, Caroline; Cabochette, Pauline; Parain, Karine; Mazurier, Nicolas; Janssens, Sylvie; Tran, Hong Thi; Sekkali, Belaïd; Bronchain, Odile; Vleminckx, Kris; Locker, Morgane; Perron, Muriel

    2012-10-01

    Continuous neurogenesis in the adult nervous system requires a delicate balance between proliferation and differentiation. Although Wnt/β-catenin and Hedgehog signalling pathways are thought to share a mitogenic function in adult neural stem/progenitor cells, it remains unclear how they interact in this process. Adult amphibians produce retinal neurons from a pool of neural stem cells localised in the ciliary marginal zone (CMZ). Surprisingly, we found that perturbations of the Wnt and Hedgehog pathways result in opposite proliferative outcomes of neural stem/progenitor cells in the CMZ. Additionally, our study revealed that Wnt and Hedgehog morphogens are produced in mutually exclusive territories of the post-embryonic retina. Using genetic and pharmacological tools, we found that the Wnt and Hedgehog pathways exhibit reciprocal inhibition. Our data suggest that Sfrp-1 and Gli3 contribute to this negative cross-regulation. Altogether, our results reveal an unexpected antagonistic interplay of Wnt and Hedgehog signals that may tightly regulate the extent of neural stem/progenitor cell proliferation in the Xenopus retina.

  5. Regulation of Inflammatory Pathways in Cancer and Infectious Disease of the Cervix

    Directory of Open Access Journals (Sweden)

    Anthonio Adefuye

    2012-01-01

    Full Text Available Cervical cancer is one of the leading gynaecological malignancies worldwide. It is an infectious disease of the cervix, associated with human papillomavirus infection (HPV, infection with bacterial agents such as Chlamydia trachomatis and Neisseria gonorrhoea as well as human immunodeficiency virus (HIV. Furthermore, it is an AIDS-defining disease with an accelerated mortality in HIV-infected women with cervical cancer. With the introduction of robust vaccination strategies against HPV in the developed world, it is anticipated that the incidence of cervical cancer will decrease in the coming years. However, vaccination has limited benefit for women already infected with high-risk HPV, and alternative therapeutic intervention strategies are needed for these women. Many pathological disorders, including cervical cancer, are characterised by the exacerbated activation and maintenance of inflammatory pathways which are considered to be regulated by infectious agents. In cervical cancer, hyperactivation of these inflammatory pathways and regulation of immune infiltrate into tissues can potentially play a role not only in tumorigenesis but also in HIV infection. In this paper we will discuss the contribution of inflammatory pathways to cervical cancer progression and HIV infection and the role of HIV in cervical cancer progression.

  6. Interaction of PACAP with Sonic hedgehog reveals complex regulation of the hedgehog pathway by PKA.

    Science.gov (United States)

    Niewiadomski, Pawel; Zhujiang, Annie; Youssef, Mary; Waschek, James A

    2013-11-01

    Sonic hedgehog (Shh) signaling is essential for proliferation of cerebellar granule cell progenitors (cGCPs) and its aberrant activation causes a cerebellar cancer medulloblastoma. Pituitary adenylate cyclase activating polypeptide (PACAP) inhibits Shh-driven proliferation of cGCPs and acts as tumor suppressor in murine medulloblastoma. We show that PACAP blocks canonical Shh signaling by a mechanism that involves activation of protein kinase A (PKA) and inhibition of the translocation of the Shh-dependent transcription factor Gli2 into the primary cilium. PKA is shown to play an essential role in inhibiting gene transcription in the absence of Shh, but global PKA activity levels are found to be a poor predictor of the degree of Shh pathway activation. We propose that the core Shh pathway regulates a small compartmentalized pool of PKA in the vicinity of primary cilia. GPCRs that affect global PKA activity levels, such as the PACAP receptor, cooperate with the canonical Shh signal to regulate Gli protein phosphorylation by PKA. This interaction serves to fine-tune the transcriptional and physiological function of the Shh pathway.

  7. Regulation of the PI3K pathway through a p85α monomer–homodimer equilibrium

    KAUST Repository

    Cheung, Lydia W T

    2015-07-29

    The canonical action of the p85α regulatory subunit of phosphatidylinositol 3-kinase (PI3K) is to associate with the p110α catalytic subunit to allow stimuli-dependent activation of the PI3K pathway. We elucidate a p110α-independent role of homodimerized p85α in the positive regulation of PTEN stability and activity. p110α-free p85α homodimerizes via two intermolecular interactions (SH3:proline-rich region and BH:BH) to selectively bind unphosphorylated activated PTEN. As a consequence, homodimeric but not monomeric p85α suppresses the PI3K pathway by protecting PTEN from E3 ligase WWP2-mediated proteasomal degradation. Further, the p85α homodimer enhances the lipid phosphatase activity and membrane association of PTEN. Strikingly, we identified cancer patient-derived oncogenic p85α mutations that target the homodimerization or PTEN interaction surface. Collectively, our data suggest the equilibrium of p85α monomerdimers regulates the PI3K pathway and disrupting this equilibrium could lead to disease development. © Cheung et al.

  8. Molecular Pathways Regulating Macrovascular Pathology and Vascular Smooth Muscle Cells Phenotype in Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Sara Casella

    2015-10-01

    Full Text Available Type 2 diabetes mellitus (T2DM is a disease reaching a pandemic proportion in developed countries and a major risk factor for almost all cardiovascular diseases and their adverse clinical manifestations. T2DM leads to several macrovascular and microvascular alterations that influence the progression of cardiovascular diseases. Vascular smooth muscle cells (VSMCs are fundamental players in macrovascular alterations of T2DM patients. VSMCs display phenotypic and functional alterations that reflect an altered intracellular biomolecular scenario of great vessels of T2DM patients. Hyperglycemia itself and through intraparietal accumulation of advanced glycation-end products (AGEs activate different pathways, in particular nuclear factor-κB and MAPKs, while insulin and insulin growth-factor receptors (IGFR are implicated in the activation of Akt and extracellular-signal-regulated kinases (ERK 1/2. Nuclear factor-κB is also responsible of increased susceptibility of VSMCs to pro-apoptotic stimuli. Down-regulation of insulin growth-factor 1 receptors (IGFR-1R activity in diabetic vessels also influences negatively miR-133a levels, so increasing apoptotic susceptibility of VSMCs. Alterations of those bimolecular pathways and related genes associate to the prevalence of a synthetic phenotype of VSMCs induces extracellular matrix alterations of great vessels. A better knowledge of those biomolecular pathways and related genes in VSMCs will help to understand the mechanisms leading to macrovascular alterations in T2DM patients and to suggest new targeted therapies.

  9. Distinct amino acid-sensing mTOR pathways regulate skeletal myogenesis.

    Science.gov (United States)

    Yoon, Mee-Sup; Chen, Jie

    2013-12-01

    Signaling through the mammalian target of rapamycin (mTOR) in response to amino acid availability controls many cellular and developmental processes. mTOR is a master regulator of myogenic differentiation, but the pathways mediating amino acid signals in this process are not known. Here we examine the Rag GTPases and the class III phosphoinositide 3-kinase (PI3K) Vps34, two mediators of amino acid signals upstream of mTOR complex 1 (mTORC1) in cell growth regulation, for their potential involvement in myogenesis. We find that, although both Rag and Vps34 mediate amino acid activation of mTORC1 in C2C12 myoblasts, they have opposing functions in myogenic differentiation. Knockdown of RagA/B enhances, whereas overexpression of active RagB/C mutants impairs, differentiation, and this inhibitory function of Rag is mediated by mTORC1 suppression of the IRS1-PI3K-Akt pathway. On the other hand, Vps34 is required for myogenic differentiation. Amino acids activate a Vps34-phospholipase D1 (PLD1) pathway that controls the production of insulin-like growth factor II, an autocrine inducer of differentiation, through the Igf2 muscle enhancer. The product of PLD, phosphatidic acid, activates the enhancer in a rapamycin-sensitive but mTOR kinase-independent manner. Our results uncover amino acid-sensing mechanisms controlling the homeostasis of myogenesis and underline the versatility and context dependence of mTOR signaling.

  10. Neurofilament heavy polypeptide regulates the Akt-beta-catenin pathway in human esophageal squamous cell carcinoma.

    Directory of Open Access Journals (Sweden)

    Myoung Sook Kim

    Full Text Available Aerobic glycolysis and mitochondrial dysfunction are common features of aggressive cancer growth. We observed promoter methylation and loss of expression in neurofilament heavy polypeptide (NEFH in a significant proportion of primary esophageal squamous cell carcinoma (ESCC samples that were of a high tumor grade and advanced stage. RNA interference-mediated knockdown of NEFH accelerated ESCC cell growth in culture and increased tumorigenicity in vivo, whereas forced expression of NEFH significantly inhibited cell growth and colony formation. Loss of NEFH caused up-regulation of pyruvate kinase-M2 type and down-regulation of pyruvate dehydrogenase, via activation of the Akt/beta-catenin pathway, resulting in enhanced aerobic glycolysis and mitochondrial dysfunction. The acceleration of glycolysis and mitochondrial dysfunction in NEFH-knockdown cells was suppressed in the absence of beta-catenin expression, and was decreased by the treatment of 2-Deoxyglucose, a glycolytic inhibitor, or API-2, an Akt inhibitor. Loss of NEFH activates the Akt/beta-catenin pathway and increases glycolysis and mitochondrial dysfunction. Cancer cells with methylated NEFH can be targeted for destruction with specific inhibitors of deregulated downstream pathways.

  11. RICTOR involvement in the PI3K/AKT pathway regulation in melanocytes and melanoma.

    Science.gov (United States)

    Laugier, Florence; Finet-Benyair, Adeline; André, Jocelyne; Rachakonda, P Sivaramakrishna; Kumar, Rajiv; Bensussan, Armand; Dumaz, Nicolas

    2015-09-29

    Several studies have highlighted the importance of the PI3K pathway in melanocytes and its frequent over-activation in melanoma. However, little is known about regulation of the PI3K pathway in melanocytic cells. We showed that normal human melanocytes are less sensitive to selective PI3K or mTOR inhibitors than to dual PI3K/mTOR inhibitors. The resistance to PI3K inhibitor was due to a rapid AKT reactivation limiting the inhibitor effect on proliferation. Reactivation of AKT was linked to a feedback mechanism involving the mTORC2 complex and in particular its scaffold protein RICTOR. RICTOR overexpression in melanocytes disrupted the negative feedback, activated the AKT pathway and stimulated clonogenicity highlighting the importance of this feedback to restrict melanocyte proliferation. We found that the RICTOR locus is frequently amplified and overexpressed in melanoma and that RICTOR over-expression in NRAS-transformed melanocytes stimulates their clonogenicity, demonstrating that RICTOR amplification can cooperate with NRAS mutation to stimulate melanoma proliferation. These results show that RICTOR plays a central role in PI3K pathway negative feedback in melanocytes and that its deregulation could be involved in melanoma development.

  12. The role of phosphatidylinositol signaling pathway in regulating serotonin-induced oocyte maturation in Mercenaria mercenaria

    Institute of Scientific and Technical Information of China (English)

    WANG Qing; ZHANG Tao

    2011-01-01

    Serotonin (5-HT) has been found to stimulate meiotic maturation of oocytes in many molluscs. During maturation, several signaling pathways are involved, especially the phosphatidylinositol and cAMP pathways. In order to examine the possible role of the phosphatidylinositol signaling pathway in regulating oocyte maturation in Mercenaria mercenaria, the effects of the activator/inhibitor of phospholipase (PLC) and protein kinase C (PKC) on serotonin-induced maturation were studied. Results show that high-concentrations of neomycin (inhibitor of PLC) blocked oocyte maturation, while 9, 10-dimethyl- 1, 2-benzanthracene (DMBA, activator of PLC) promoted oocyte maturation in the presence of serotonin. It was also found that in the presence of serotonin, phorbol 12-myristate 13-acetate (PMA,activator of PKC) inhibited oocyte maturation, while sphingosine (inhibitor of PKC) stimulated oocyte maturation. These results indicate that serotonin-induced oocyte maturation requires the activation of the phosphatidylinositol pathway. Decrease of PLC inhibited serotonin-induced oocyte maturation, whereas a decrease of PKC stimulated the maturation. Thus, our study indicates that serotonin promotes maturation of M. mercenaria oocytes through PLC stimulated increase in calcium ion concentration via inositol-1,4, 5-trisphosphate (IP3) but not PKC.

  13. miR-24 regulates intrinsic apoptosis pathway in mouse cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Li Wang

    Full Text Available Numerous cardiac diseases, including myocardial infarction (MI and chronic heart failure, have been associated with cardiomyocyte apoptosis. Promoting cell survival by inhibiting apoptosis is one of the effective strategies to attenuate cardiac dysfunction caused by cardiomyocyte loss. miR-24 has been shown as an anti-apoptotic microRNA in various animal models. In vivo delivery of miR-24 into a mouse MI model suppressed cardiac cell death, attenuated infarct size, and rescued cardiac dysfunction. However, the molecular pathway by which miR-24 inhibits cardiomyocyte apoptosis is not known. Here we found that miR-24 negatively regulates mouse primary cadiomyocyte cell death through functioning in the intrinsic apoptotic pathways. In ER-mediated intrinsic pathway, miR-24 genetically interacts with the CEBP homologous gene CHOP as knocking down of CHOP partially attenuated the induced apoptosis by miR-24 inhibition. In mitochondria-involved intrinsic pathway, miR-24 inhibits the initiation of apoptosis through suppression of Cytochrome C release and Bax translocation from cytosol to mitochondria. These results provide mechanistic insights into the miR-24 mediated anti-apoptotic effects in murine cardiomyocytes.

  14. Berberine regulates neurite outgrowth through AMPK-dependent pathways by lowering energy status

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jiaqi; Cao, Yuanzhao; Cheng, Kuoyuan; Xu, Bo; Wang, Tianchang; Yang, Qi; Yang, Qin [State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing (China); Feng, Xudong, E-mail: xudong.feng@childrens.harvard.edu [Department of Medicine, Children' s Hospital Boston, Harvard Medical School, 300 Longwood Ave, Boston, MA 02115 (United States); Xia, Qing, E-mail: xqing@hsc.pku.edu.cn [State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing (China)

    2015-06-10

    As a widely used anti-bacterial agent and a metabolic inhibitor as well as AMP-activated protein kinase (AMPK) activator, berberine (BBR) has been shown to cross the blood–brain barrier. Its efficacy has been investigated in various disease models of the central nervous system. Neurite outgrowth is critical for nervous system development and is a highly energy-dependent process regulated by AMPK-related pathways. In the present study, we aimed to investigate the effects of BBR on AMPK activation and neurite outgrowth in neurons. The neurite outgrowth of primary rat cortical neurons at different stages of polarization was monitored after exposure of BBR. Intracellular energy level, AMPK activation and polarity-related pathways were also inspected. The results showed that BBR suppressed neurite outgrowth and affected cytoskeleton stability in the early stages of neuronal polarization, which was mediated by lowered energy status and AMPK activation. Liver kinase B1 and PI3K–Akt–GSK3β signaling pathways were also involved. In addition, mitochondrial dysfunction and endoplasmic reticulum stress contributed to the lowered energy status induced by BBR. This study highlighted the knowledge of the complex activities of BBR in neurons and corroborated the significance of energy status during the neuronal polarization. - Highlights: • BBR inhibited neurite outgrowth in early stages of neuronal development. • Lowered neuronal energy status was induced by BBR treatment. • Neuronal energy stress induced by BBR activated AMPK-related pathways. • BBR induced mitochondrial dysfunction and endoplasmic reticulum stress.

  15. Toll-like receptor 3 regulates neural stem cell proliferation by modulating the Sonic Hedgehog pathway.

    Directory of Open Access Journals (Sweden)

    Kavitha Yaddanapudi

    Full Text Available Toll-like receptor 3 (TLR3 signaling has been implicated in neural stem/precursor cell (NPC proliferation. However, the molecular mechanisms involved, and their relationship to classical TLR-mediated innate immune pathways, remain unknown. Here, we report investigation of the mechanics of TLR3 signaling in neurospheres comprised of epidermal growth factor (EGF-responsive NPC isolated from murine embryonic cerebral cortex of C57BL/6 (WT or TLR3 deficient (TLR3(-/- mice. Our data indicate that the TLR3 ligand polyinosinic-polycytidylic acid (PIC negatively regulates NPC proliferation by inhibiting Sonic Hedgehog (Shh signaling, that PIC induces apoptosis in association with inhibition of Ras-ERK signaling and elevated expression of Fas, and that these effects are TLR3-dependent, suggesting convergent signaling between the Shh and TLR3 pathways.

  16. Down regulation of gene related sex hormone synthesis pathway in mouse testes by miroestrol and deoxymiroestrol.

    Science.gov (United States)

    Udomsuk, Latiporn; Juengwatanatrakul, Thaweesak; Putalun, Waraporn; Jarukamjorn, Kanokwan

    2011-12-01

    Miroestrol and deoxymiroestrol are phytoestrogens isolated from tuberous root of Pueraria candollei var. mirifica. Modulatory effects of miroestrol and deoxymiroestrol on enzymes involved in sex-hormone synthesis pathway in male C57BL/6 mice were investigated using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Miroestrol and deoxymiroestrol suppressed the expressions of 3β-HSD, 17β-HSD1, and CYP17 while CYP19 mRNA expression was slightly decreased. In addition, the expression of 17β-HSD2 was induced in correlation with those did by estradiol. These observations supported that miroestrol and deoxymiroestrol could exhibit the same effect as estradiol regarding regulation of testicular gene related sex hormone synthesis pathway.

  17. A nuclear receptor-like pathway regulating multidrug resistance in fungi.

    Science.gov (United States)

    Thakur, Jitendra K; Arthanari, Haribabu; Yang, Fajun; Pan, Shih-Jung; Fan, Xiaochun; Breger, Julia; Frueh, Dominique P; Gulshan, Kailash; Li, Darrick K; Mylonakis, Eleftherios; Struhl, Kevin; Moye-Rowley, W Scott; Cormack, Brendan P; Wagner, Gerhard; Näär, Anders M

    2008-04-03

    Multidrug resistance (MDR) is a serious complication during treatment of opportunistic fungal infections that frequently afflict immunocompromised individuals, such as transplant recipients and cancer patients undergoing cytotoxic chemotherapy. Improved knowledge of the molecular pathways controlling MDR in pathogenic fungi should facilitate the development of novel therapies to combat these intransigent infections. MDR is often caused by upregulation of drug efflux pumps by members of the fungal zinc-cluster transcription-factor family (for example Pdr1p orthologues). However, the molecular mechanisms are poorly understood. Here we show that Pdr1p family members in Saccharomyces cerevisiae and the human pathogen Candida glabrata directly bind to structurally diverse drugs and xenobiotics, resulting in stimulated expression of drug efflux pumps and induction of MDR. Notably, this is mechanistically similar to regulation of MDR in vertebrates by the PXR nuclear receptor, revealing an unexpected functional analogy of fungal and metazoan regulators of MDR. We have also uncovered a critical and specific role of the Gal11p/MED15 subunit of the Mediator co-activator and its activator-targeted KIX domain in antifungal/xenobiotic-dependent regulation of MDR. This detailed mechanistic understanding of a fungal nuclear receptor-like gene regulatory pathway provides novel therapeutic targets for the treatment of multidrug-resistant fungal infections.

  18. Spatial Regulation of Root Growth: Placing the Plant TOR Pathway in a Developmental Perspective.

    Science.gov (United States)

    Barrada, Adam; Montané, Marie-Hélène; Robaglia, Christophe; Menand, Benoît

    2015-08-19

    Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate in the division zone of the meristem, and then increase in length in the elongation zone, reaching their final size and differentiation stage in the mature zone. Phytohormones, especially auxins and cytokinins, control the dynamic balance between cell division and differentiation and therefore organ size. Plant growth is also regulated by metabolites and nutrients, such as the sugars produced by photosynthesis or nitrate assimilated from the soil. Recent literature has shown that the conserved eukaryotic TOR (target of rapamycin) kinase pathway plays an important role in orchestrating plant growth. We will summarize how the regulation of cell proliferation and cell expansion by phytohormones are at the heart of root growth and then discuss recent data indicating that the TOR pathway integrates hormonal and nutritive signals to orchestrate root growth.

  19. The CRTC1-SIK1 pathway regulates entrainment of the circadian clock.

    Science.gov (United States)

    Jagannath, Aarti; Butler, Rachel; Godinho, Sofia I H; Couch, Yvonne; Brown, Laurence A; Vasudevan, Sridhar R; Flanagan, Kevin C; Anthony, Daniel; Churchill, Grant C; Wood, Matthew J A; Steiner, Guido; Ebeling, Martin; Hossbach, Markus; Wettstein, Joseph G; Duffield, Giles E; Gatti, Silvia; Hankins, Mark W; Foster, Russell G; Peirson, Stuart N

    2013-08-29

    Retinal photoreceptors entrain the circadian system to the solar day. This photic resetting involves cAMP response element binding protein (CREB)-mediated upregulation of Per genes within individual cells of the suprachiasmatic nuclei (SCN). Our detailed understanding of this pathway is poor, and it remains unclear why entrainment to a new time zone takes several days. By analyzing the light-regulated transcriptome of the SCN, we have identified a key role for salt inducible kinase 1 (SIK1) and CREB-regulated transcription coactivator 1 (CRTC1) in clock re-setting. An entrainment stimulus causes CRTC1 to coactivate CREB, inducing the expression of Per1 and Sik1. SIK1 then inhibits further shifts of the clock by phosphorylation and deactivation of CRTC1. Knockdown of Sik1 within the SCN results in increased behavioral phase shifts and rapid re-entrainment following experimental jet lag. Thus SIK1 provides negative feedback, acting to suppress the effects of light on the clock. This pathway provides a potential target for the regulation of circadian rhythms.

  20. Unraveling the Specific Regulation of the Central Pathway for Anaerobic Degradation of 3-Methylbenzoate*

    Science.gov (United States)

    Juárez, Javier F.; Liu, Huixiang; Zamarro, María T.; McMahon, Stephen; Liu, Huanting; Naismith, James H.; Eberlein, Christian; Boll, Matthias; Carmona, Manuel; Díaz, Eduardo

    2015-01-01

    The mbd cluster encodes the anaerobic degradation of 3-methylbenzoate in the β-proteobacterium Azoarcus sp. CIB. The specific transcriptional regulation circuit that controls the expression of the mbd genes was investigated. The PO, PB1, and P3R promoters responsible for the expression of the mbd genes, their cognate MbdR transcriptional repressor, as well as the MbdR operator regions (ATACN10GTAT) have been characterized. The three-dimensional structure of MbdR has been solved revealing a conformation similar to that of other TetR family transcriptional regulators. The first intermediate of the catabolic pathway, i.e. 3-methylbenzoyl-CoA, was shown to act as the inducer molecule. An additional MbdR-dependent promoter, PA, which contributes to the expression of the CoA ligase that activates 3-methylbenzoate to 3-methylbenzoyl-CoA, was shown to be necessary for an efficient induction of the mbd genes. Our results suggest that the mbd cluster recruited a regulatory system based on the MbdR regulator and its target promoters to evolve a distinct central catabolic pathway that is only expressed for the anaerobic degradation of aromatic compounds that generate 3-methylbenzoyl-CoA as the central metabolite. All these results highlight the importance of the regulatory systems in the evolution and adaptation of bacteria to the anaerobic degradation of aromatic compounds. PMID:25795774

  1. Regulated ADAM17-dependent EGF family ligand release by substrate-selecting signaling pathways.

    Science.gov (United States)

    Dang, Michelle; Armbruster, Nicole; Miller, Miles A; Cermeno, Efrain; Hartmann, Monika; Bell, George W; Root, David E; Lauffenburger, Douglas A; Lodish, Harvey F; Herrlich, Andreas

    2013-06-11

    Ectodomain cleavage of cell-surface proteins by A disintegrin and metalloproteinases (ADAMs) is highly regulated, and its dysregulation has been linked to many diseases. ADAM10 and ADAM17 cleave most disease-relevant substrates. Broad-spectrum metalloprotease inhibitors have failed clinically, and targeting the cleavage of a specific substrate has remained impossible. It is therefore necessary to identify signaling intermediates that determine substrate specificity of cleavage. We show here that phorbol ester or angiotensin II-induced proteolytic release of EGF family members may not require a significant increase in ADAM17 protease activity. Rather, inducers activate a signaling pathway using PKC-α and the PKC-regulated protein phosphatase 1 inhibitor 14D that is required for ADAM17 cleavage of TGF-α, heparin-binding EGF, and amphiregulin. A second pathway involving PKC-δ is required for neuregulin (NRG) cleavage, and, indeed, PKC-δ phosphorylation of serine 286 in the NRG cytosolic domain is essential for induced NRG cleavage. Thus, signaling-mediated substrate selection is clearly distinct from regulation of enzyme activity, an important mechanism that offers itself for application in disease.

  2. Crosstalk between the unfolded protein response and pathways that regulate pathogenic development in Ustilago maydis.

    Science.gov (United States)

    Heimel, Kai; Freitag, Johannes; Hampel, Martin; Ast, Julia; Bölker, Michael; Kämper, Jörg

    2013-10-01

    The unfolded protein response (UPR) is a conserved eukaryotic signaling pathway regulating endoplasmic reticulum (ER) homeostasis during ER stress, which results, for example, from an increased demand for protein secretion. Here, we characterize the homologs of the central UPR regulatory proteins Hac1 (for Homologous to ATF/CREB1) and Inositol Requiring Enzyme1 in the plant pathogenic fungus Ustilago maydis and demonstrate that the UPR is tightly interlinked with the b mating-type-dependent signaling pathway that regulates pathogenic development. Exact timing of UPR is required for virulence, since premature activation interferes with the b-dependent switch from budding to filamentous growth. In addition, we found crosstalk between UPR and the b target Clampless1 (Clp1), which is essential for cell cycle release and proliferation in planta. The unusual C-terminal extension of the U. maydis Hac1 homolog, Cib1 (for Clp1 interacting bZIP1), mediates direct interaction with Clp1. The interaction between Clp1 and Cib1 promotes stabilization of Clp1, resulting in enhanced ER stress tolerance that prevents deleterious UPR hyperactivation. Thus, the interaction between Cib1 and Clp1 constitutes a checkpoint to time developmental progression and increased secretion of effector proteins at the onset of biotrophic development. Crosstalk between UPR and the b mating-type regulated developmental program adapts ER homeostasis to the changing demands during biotrophy.

  3. Spatial Regulation of Root Growth: Placing the Plant TOR Pathway in a Developmental Perspective

    Directory of Open Access Journals (Sweden)

    Adam Barrada

    2015-08-01

    Full Text Available Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate in the division zone of the meristem, and then increase in length in the elongation zone, reaching their final size and differentiation stage in the mature zone. Phytohormones, especially auxins and cytokinins, control the dynamic balance between cell division and differentiation and therefore organ size. Plant growth is also regulated by metabolites and nutrients, such as the sugars produced by photosynthesis or nitrate assimilated from the soil. Recent literature has shown that the conserved eukaryotic TOR (target of rapamycin kinase pathway plays an important role in orchestrating plant growth. We will summarize how the regulation of cell proliferation and cell expansion by phytohormones are at the heart of root growth and then discuss recent data indicating that the TOR pathway integrates hormonal and nutritive signals to orchestrate root growth.

  4. Spatial Regulation of Root Growth: Placing the Plant TOR Pathway in a Developmental Perspective

    Science.gov (United States)

    Barrada, Adam; Montané, Marie-Hélène; Robaglia, Christophe; Menand, Benoît

    2015-01-01

    Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate in the division zone of the meristem, and then increase in length in the elongation zone, reaching their final size and differentiation stage in the mature zone. Phytohormones, especially auxins and cytokinins, control the dynamic balance between cell division and differentiation and therefore organ size. Plant growth is also regulated by metabolites and nutrients, such as the sugars produced by photosynthesis or nitrate assimilated from the soil. Recent literature has shown that the conserved eukaryotic TOR (target of rapamycin) kinase pathway plays an important role in orchestrating plant growth. We will summarize how the regulation of cell proliferation and cell expansion by phytohormones are at the heart of root growth and then discuss recent data indicating that the TOR pathway integrates hormonal and nutritive signals to orchestrate root growth. PMID:26295391

  5. Src promotes cutaneous wound healing by regulating MMP-2 through the ERK pathway.

    Science.gov (United States)

    Wu, Xue; Yang, Longlong; Zheng, Zhao; Li, Zhenzhen; Shi, Jihong; Li, Yan; Han, Shichao; Gao, Jianxin; Tang, Chaowu; Su, Linlin; Hu, Dahai

    2016-03-01

    Wound healing is a highly orchestrated, multistep process, and delayed wound healing is a significant symptomatic clinical problem. Keratinocyte migration and re-epithelialization play the most important roles in wound healing, as they determine the rate of wound healing. In our previous study, we found that Src, one of the oldest proto‑oncogenes encoding a membrane-associated, non-receptor protein tyrosine kinase, promotes keratinocyte migration. We therefore hypothesized that Src promotes wound healing through enhanced keratinocyte migration. In order to test this hypothesis, vectors for overexpressing Src and small interfering RNAs (siRNAs) for silencing of Src were used in the present study. We found that the overexpression of Src accelerated keratinocyte migration in vitro and promoted wound healing in vivo without exerting a marked effect on cell proliferation. The extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways play important roles in Src-accelerated keratinocyte migration. Further experiments demonstrated that Src induced the protein expression of matrix metalloproteinase-2 (MMP-2) and decreased the protein expression of E-cadherin. We suggest that ERK signaling is involved in the Src-mediated regulation of MMP-2 expression. The present study provided evidence that Src promotes keratinocyte migration and cutaneous wound healing, in which the regulation of MMP-2 through the ERK pathway plays an important role, and thus we also demonstrated a potential therapeutic role for Src in cutaneous wound healing.

  6. Cross talk of signaling pathways in the regulation of the glucocorticoid receptor function.

    Science.gov (United States)

    Davies, Laura; Karthikeyan, Nirupama; Lynch, James T; Sial, Elin-Alia; Gkourtsa, Areti; Demonacos, Constantinos; Krstic-Demonacos, Marija

    2008-06-01

    Several posttranslational modifications including phosphorylation have been detected on the glucocorticoid receptor (GR). However, the interdependence and combinatorial regulation of these modifications and their role in GR functions are poorly understood. We studied the effects of c-Jun N-terminal kinase (JNK)-dependent phosphorylation of GR on its sumoylation status and the impact that these modifications have on GR transcriptional activity. GR is targeted for phosphorylation at serine 246 (S246) by the JNK protein family in a rapid and transient manner. The levels of S246 phosphorylation of endogenous GR increased significantly in cells treated with UV radiation that activates JNK. S246 GR phosphorylation by JNK facilitated subsequent GR sumoylation at lysines 297 and 313. GR sumoylation increased with JNK activation and was inhibited in cells treated with JNK inhibitor. GR sumoylation in cells with activated JNK was mediated preferentially by small ubiquitin-like modifier (SUMO)2 rather than SUMO1. An increase in GR transcriptional activity was observed after inhibition of JNK or SUMO pathways and suppression of GR transcriptional activity after activation of both pathways in cells transfected with GR-responsive reporter genes. Endogenous GR transcriptional activity was inhibited on endogenous target genes IGF binding protein (IGFBP) and glucocorticoid-induced leucine zipper (GILZ) when JNK and SUMO pathways were induced individually or simultaneously. Activation of both of these signals inhibited GR-mediated regulation of human inhibitor of apoptosis gene (hIAP), whereas simultaneous activation had no effect. We conclude that phosphorylation aids GR sumoylation and that cross talk of JNK and SUMO pathways fine tune GR transcriptional activity in a target gene-specific manner, thereby modulating the hormonal response of cells exposed to stress.

  7. Oncogenic microRNA-4534 regulates PTEN pathway in prostate cancer.

    Science.gov (United States)

    Nip, Hannah; Dar, Altaf A; Saini, Sharanjot; Colden, Melissa; Varahram, Shahryari; Chowdhary, Harshika; Yamamura, Soichiro; Mitsui, Yozo; Tanaka, Yuichiro; Kato, Taku; Hashimoto, Yutaka; Shiina, Marisa; Kulkarni, Priyanka; Dasgupta, Pritha; Imai-Sumida, Mitsuho; Tabatabai, Z Laura; Greene, Kirsten; Deng, Guoren; Dahiya, Rajvir; Majid, Shahana

    2016-10-18

    Prostate carcinogenesis involves alterations in several signaling pathways, the most prominent being the PI3K/AKT pathway. This pathway is constitutively active and drives prostate cancer (PCa) progression to advanced metastatic disease. PTEN, a critical tumor and metastasis suppressor gene negatively regulates cell survival, proliferation, migration and angiogenesis via the PI3K/Akt pathway. PTEN is mutated, downregulated/dysfunctional in many cancers and its dysregulation correlates with poor prognosis in PCa. Here, we demonstrate that microRNA-4534 (miR-4534) is overexpressed in PCa and show that miR-4534 is hypermethylated in normal tissues and cell lines compared to PCa tissues/cells. miR-4534 exerts its oncogenic effects partly by downregulating the tumor suppressor PTEN gene. Knockdown of miR-4534 impaired cell proliferation, migration/invasion and induced G0/G1 cell cycle arrest and apoptosis in PCa. Suppression of miR-4534 and its effects on tumor growth was confirmed in a xenograft mouse model. We performed parallel experiments in non-cancer RWPE1 cells by overexpessing miR-4534 followed by functional assays. Overexpression of miR-4534 induced pro-cancerous characteristics in this non-cancer cell line. Statistical analyses revealed that miR-4534 has potential to independently distinguish malignant from normal tissues and positively correlated with poor overall and PSA recurrence free survival. Taken together, our results show that depletion of miR-4534 in PCa induces a tumor suppressor phenotype partly through induction of PTEN. These results have important implications for identifying and defining the role of new PTEN regulators such as microRNAs in prostate tumorigenesis. Understanding aberrantly overexpressed miR-4534 and its downregulation of PTEN will provide mechanistic insight and therapeutic targets for PCa therapy.

  8. Eight paths of ERK1/2 signalling pathway regulating hepatocyte proliferation in rat liver regeneration

    Indian Academy of Sciences (India)

    J. W. Li; G. P. Wang; J. Y. Fan; C. F. Chang; C. S. Xu

    2011-12-01

    Although it is known that hormones, growth factors and integrin promote hepatocyte proliferation in liver regeneration (LR) through ERK1/2 signalling pathway, reports about regulating processes of its intracellular paths in hepatocytes of LR are limited. This study aims at exploring which paths of ERK1/2 signalling pathway participate in the regulation of rat LR, especially in hepatocyte proliferation, and how they do so. In all, 14 paths and 165 genes are known to be involved in ERK1/2 signalling pathway. Of them, 161 genes are included in Rat Genome 230 2.0 Array. This array was used to detect expression changes of genes related to ERK1/2 signalling pathway in isolated hepatocytes of rat LR, showing that 60 genes were related to hepatocytes of LR. In addition, bioinformatics and systems biology methods were used to analyse the roles of 14 above paths in regenerating hepatocytes. We found that three paths, RTK → SHC → GRB2/SOS → RAS → RAF, Integrin → FAK → RAC → PAK → RAF and G → PI3K → RAC → PAK → RAF, promoted the G1 phase progression of hepatocytes by activating ERK1/2. A further four paths, Gq → PLC → PKC → SRC/PYK2 → GRB2/SOS → RAS → RAF, RTK → PLC → PKC → SRC/PYK2 → GRB2/SOS → RAS → RAF, Integrin → FAK/SRC → GRB2/SOS → RAS → RAF and Integrin → FAK → RAC → PAK → RAF, advanced the cell progression of S phase and G2/M checkpoint by activating ERK1/2, and so did PP1/2 → Mek1/2 by decreasing the negative influence on ERK1/2. At the late phase of LR, Gs → AC → EPAC → Rap1 → Raf blocked hepatocyte proliferation by decreasing the activity of ERK1/2 and so did PP1/2 → Mek1/2. In summary, 60 genes and 8 paths of ERK1/2 signalling pathway regulated hepatocyte proliferation in rat LR.

  9. Identification of cisplatin-regulated metabolic pathways in pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Louise von Stechow

    Full Text Available The chemotherapeutic compound, cisplatin causes various kinds of DNA lesions but also triggers other pertubations, such as ER and oxidative stress. We and others have shown that treatment of pluripotent stem cells with cisplatin causes a plethora of transcriptional and post-translational alterations that, to a major extent, point to DNA damage response (DDR signaling. The orchestrated DDR signaling network is important to arrest the cell cycle and repair the lesions or, in case of damage beyond repair, eliminate affected cells. Failure to properly balance the various aspects of the DDR in stem cells contributes to ageing and cancer. Here, we performed metabolic profiling by mass spectrometry of embryonic stem (ES cells treated for different time periods with cisplatin. We then integrated metabolomics with transcriptomics analyses and connected cisplatin-regulated metabolites with regulated metabolic enzymes to identify enriched metabolic pathways. These included nucleotide metabolism, urea cycle and arginine and proline metabolism. Silencing of identified proline metabolic and catabolic enzymes indicated that altered proline metabolism serves as an adaptive, rather than a toxic response. A group of enriched metabolic pathways clustered around the metabolite S-adenosylmethionine, which is a hub for methylation and transsulfuration reactions and polyamine metabolism. Enzymes and metabolites with pro- or anti-oxidant functions were also enriched but enhanced levels of reactive oxygen species were not measured in cisplatin-treated ES cells. Lastly, a number of the differentially regulated metabolic enzymes were identified as target genes of the transcription factor p53, pointing to p53-mediated alterations in metabolism in response to genotoxic stress. Altogether, our findings reveal interconnecting metabolic pathways that are responsive to cisplatin and may serve as signaling modules in the DDR in pluripotent stem cells.

  10. Salinity-induced regulation of the myo-inositol biosynthesis pathway in tilapia gill epithelium.

    Science.gov (United States)

    Sacchi, Romina; Li, Johnathon; Villarreal, Fernando; Gardell, Alison M; Kültz, Dietmar

    2013-12-15

    The myo-inositol biosynthesis (MIB) pathway converts glucose-6-phosphate to the compatible osmolyte myo-inositol that protects cells from osmotic stress. Using proteomics, the enzymes that constitute the MIB pathway, myo-inositol phosphate synthase (MIPS) and inositol monophosphatase 1 (IMPA1), are identified in tilapia (Oreochromis mossambicus) gill epithelium. Targeted, quantitative, label-free proteomics reveals that they are both upregulated during salinity stress. Upregulation is stronger when fish are exposed to severe (34 ppt acute and 90 ppt gradual) relative to moderate (70 ppt gradual) salinity stress. IMPA1 always responds more strongly than MIPS, suggesting that MIPS is more stable during salinity stress. MIPS is N-terminally acetylated and the corresponding peptide increases proportionally to MIPS protein, while non-acetylated N-terminal peptide is not detectable, indicating that MIPS acetylation is constitutive and may serve to stabilize the protein. Hyperosmotic induction of MIPS and IMPA1 is confirmed using western blot and real-time qPCR and is much higher at the mRNA than at the protein level. Two distinct MIPS mRNA variants are expressed in the gill, but one is more strongly regulated by salinity than the other. A single MIPS gene is encoded in the tilapia genome whereas the zebrafish genome lacks MIPS entirely. The genome of euryhaline tilapia contains four IMPA genes, two of which are expressed, but only one is salinity regulated in gill epithelium. The genome of stenohaline zebrafish contains a single IMPA gene. We conclude that the MIB pathway represents a major salinity stress coping mechanism that is regulated at multiple levels in euryhaline fish but absent in stenohaline zebrafish.

  11. Regulation of the STARS signaling pathway in response to endurance and resistance exercise and training.

    Science.gov (United States)

    Lamon, Séverine; Wallace, Marita A; Stefanetti, Renae J; Rahbek, Stine K; Vendelbo, Mikkel H; Russell, Aaron P; Vissing, Kristian

    2013-09-01

    The striated muscle activator of Rho signaling (STARS) protein and members of its downstream signaling pathway, including myocardin-related transcription factor-A (MRTF-A) and SRF, are increased in response to prolonged resistance exercise training but also following a single bout of endurance cycling. The aim of the present study was to measure and compare the regulation of STARS, MRTF-A and SRF mRNA and protein following 10 weeks of endurance training (ET) versus resistance training (RT), as well as before and following a single bout of endurance (EE) versus resistance exercise (RE). Following prolonged training, STARS, MRTF-A and SRF mRNA levels were all increased by similar magnitude, irrespective of training type. In the training-habituated state, STARS mRNA increased following a single-bout RE when measured 2.5 and 5 h post-exercise and had returned to resting level by 22 h following exercise. MRTF-A and SRF mRNA levels were decreased by 2.5, 5, and 22 h following a single bout of RE and EE exercise when compared to their respective basal levels, with no significant difference seen between the groups at any of the time points. No changes in protein levels were observed following the two modes of exercise training or a single bout of exercise. This study demonstrates that the stress signals elicited by ET and RT result in a comparable regulation of members of the STARS pathway. In contrast, a single bout of EE and RE, performed in the trained state, elicit different responses. These observations suggest that in the trained state, the acute regulation of the STARS pathway following EE or RE may be responsible for exercise-specific muscle adaptations.

  12. Early Diagnosis of Clear Cell Kidney Cancer via VHL/HIF Pathway Regulated-Circulating microRNA

    Science.gov (United States)

    2016-05-01

    Award Number: W81XWH-11-1-0715 TITLE: Early Diagnosis of Clear Cell Kidney Cancer via VHL/HIF Pathway -Regulated Circulating microRNA PRINCIPAL...TITLE AND SUBTITLE Sa. CONTRACT NUMBER Early Diagnosis of Clear Cell Kidney Cancer via VHL/HIF Pathway - Regulated Circulating microRNA Sb. GRANT NUMBER...panel of diagnostic miRNAs that are measurable in serum and will be able to identify kidney cancer in its earliest stages. We hypothesized that serum

  13. DMPD: Interferon gene regulation: not all roads lead to Tolls. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available ;11(9):403-11. Pathway - PNG File (.png) SVG File (.svg) HTML File (.html) CSML File (.csml) Open .csml file with CIOPlayer Open .csm...zgerald KA. Trends Mol Med. 2005 Sep;11(9):403-11. (.png) (.svg) (.html) (.csml) Show Interferon gene regula...l file with CIOPlayer - ※CIO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ...

  14. RNAseq analysis of the parasitic nematode Strongyloides stercoralis reveals divergent regulation of canonical dauer pathways.

    Science.gov (United States)

    Stoltzfus, Jonathan D; Minot, Samuel; Berriman, Matthew; Nolan, Thomas J; Lok, James B

    2012-01-01

    The infectious form of many parasitic nematodes, which afflict over one billion people globally, is a developmentally arrested third-stage larva (L3i). The parasitic nematode Strongyloides stercoralis differs from other nematode species that infect humans, in that its life cycle includes both parasitic and free-living forms, which can be leveraged to investigate the mechanisms of L3i arrest and activation. The free-living nematode Caenorhabditis elegans has a similar developmentally arrested larval form, the dauer, whose formation is controlled by four pathways: cyclic GMP (cGMP) signaling, insulin/IGF-1-like signaling (IIS), transforming growth factor β (TGFβ) signaling, and biosynthesis of dafachronic acid (DA) ligands that regulate a nuclear hormone receptor. We hypothesized that homologous pathways are present in S. stercoralis, have similar developmental regulation, and are involved in L3i arrest and activation. To test this, we undertook a deep-sequencing study of the polyadenylated transcriptome, generating over 2.3 billion paired-end reads from seven developmental stages. We constructed developmental expression profiles for S. stercoralis homologs of C. elegans dauer genes identified by BLAST searches of the S. stercoralis genome as well as de novo assembled transcripts. Intriguingly, genes encoding cGMP pathway components were coordinately up-regulated in L3i. In comparison to C. elegans, S. stercoralis has a paucity of genes encoding IIS ligands, several of which have abundance profiles suggesting involvement in L3i development. We also identified seven S. stercoralis genes encoding homologs of the single C. elegans dauer regulatory TGFβ ligand, three of which are only expressed in L3i. Putative DA biosynthetic genes did not appear to be coordinately regulated in L3i development. Our data suggest that while dauer pathway genes are present in S. stercoralis and may play a role in L3i development, there are significant differences between the two species

  15. The transcription factor AREB1 regulates primary metabolic pathways in tomato fruits.

    Science.gov (United States)

    Bastías, Adriana; Yañez, Mónica; Osorio, Sonia; Arbona, Vicent; Gómez-Cadenas, Aurelio; Fernie, Alisdair R; Casaretto, José A

    2014-06-01

    Tomato fruit development is regulated both by the action of plant hormones and by tight genetic control. Recent studies suggest that abscisic acid (ABA) signalling may affect different aspects of fruit maturation. Previously, it was shown that SlAREB1, an ABA-regulated transcription factor involved in stress-induced responses, is expressed in seeds and in fruit tissues in tomato. Here, the role of SlAREB1 in regulating the expression of genes relevant for primary metabolic pathways and affecting the metabolic profile of the fruit was investigated using transgenic tomato lines. Metabolite profiling using gas chromatography-time of flight mass spectrometry (GC-TOF-MS) and non-targeted liquid chromatography-mass spectrometry (LC-MS) was performed on pericarp tissue from fruits harvested at three stages of fruit development. Principal component analysis of the data could distinguish the metabolite profiles of non-transgenic fruits from those that overexpress and down-regulate SlAREB1. Overexpression of SlAREB1 resulted in increased content of organic acids, hexoses, hexose-phosphates, and amino acids in immature green, mature green, and red ripe fruits, and these modifications correlated with the up-regulation of enzyme-encoding genes involved in primary carbohydrate and amino acid metabolism. A non-targeted LC-MS analysis indicated that the composition of secondary metabolites is also affected in transgenic lines. In addition, gene expression data revealed that some genes associated with fruit ripening are also up-regulated in SlAREB1-overexpressing lines compared with wild-type and antisense lines. Taken together, the results suggest that SlAREB1 participates in the regulation of the metabolic programming that takes place during fruit ripening and that may explain part of the role of ABA in fruit development in tomato.

  16. Spatial regulation of the mTORC1 system in amino acids sensing pathway

    Institute of Scientific and Technical Information of China (English)

    Tsukasa Suzuki; Ken Inoki

    2011-01-01

    The mammalian target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine protein kinase that regulates numerous cellular processes including cell growth,proliferation,cell cycle,and autophagy,mTOR forms two different multi-protein complexes referred to as mTOR complex 1 (mTORC1) and mTORC2,and each complex exerts distinct functions exclusively,mTORC1 activity is sensitive to the selective inhibitor rapamycin,whereas mTORC2 is resistant,mTORC1 is regulated by many intra- and extra-cellular cues such as growth factors, nutrients, and energy-sensing signals,while mTORC2 senses ribosome maturation and growth factor signaling.This review focuses on current understandings by which mTORC1 pathway senses cellular nutrient availability for its activation.

  17. Identification of microRNAs regulating the developmental pathways of bone marrow derived mast cells.

    Directory of Open Access Journals (Sweden)

    Yang Xiang

    Full Text Available BACKGROUND: MicroRNAs (miRNAs play important roles in leukocyte differentiation, although those utilised for specific programs and key functions remain incompletely characterised. As a global approach to gain insights into the potential regulatory role of miRNA in mast cell differentiation we characterised expression in BM cultures from the initiation of differentiation. In cultures enriched in differentiating mast cells we characterised miRNA expression and identified miRNA targeting the mRNA of putative factors involved in differentiation pathways and cellular identity. Detailed pathway analysis identified a unique miRNA network that is intimately linked to the mast cell differentiation program. METHODOLOGY/PRINCIPAL FINDINGS: We identified 86 unique miRNAs with expression patterns that were up- or down- regulated at 5-fold or more during bone marrow derived mast cells (BMMC development. By employing TargetScan and MeSH databases, we identified 524 transcripts involved in 30 canonical pathways as potentially regulated by these specific 86 miRNAs. Furthermore, by applying miRanda and IPA analyses, we predict that 7 specific miRNAs of this group are directly associated with the expression of c-Kit and FcεRIα and likewise, that 18 miRNAs promote expression of Mitf, GATA1 and c/EBPα three core transcription factors that direct mast cell differentiation. Furthermore, we have identified 11 miRNAs that may regulate the expression of STATs-3, -5a/b, GATA2 and GATA3 during differentiation, along with 13 miRNAs that target transcripts encoding Ndst2, mMCP4 and mMCP6 and thus may regulate biosynthesis of mast cell secretory mediators. CONCLUSIONS/SIGNIFICANCE: This investigation characterises changes in miRNA expression in whole BM cultures during the differentiation of mast cells and predicts functional links between miRNAs and their target mRNAs for the regulation of development. This information provides an important resource for further

  18. A Myb transcription factor regulates genes of the phenylalanine pathway in maritime pine.

    Science.gov (United States)

    Craven-Bartle, Blanca; Pascual, M Belen; Cánovas, Francisco M; Avila, Concepción

    2013-06-01

    During the life cycles of conifer trees, such as maritime pine (Pinus pinaster Ait.), large quantities of carbon skeletons are irreversibly immobilized in the wood. In energetic terms this is an expensive process, in which carbon from photosynthesis is channelled through the shikimate pathway for the biosynthesis of phenylpropanoids. This crucial metabolic pathway is finely regulated, primarily through transcriptional control, and because phenylalanine is the precursor for phenylpropanoid biosynthesis, the precise regulation of phenylalanine synthesis and use should occur simultaneously. The promoters of three genes encoding the enzymes prephenate aminotransferase (PAT), phenylalanine ammonia lyase (PAL) and glutamine synthetase (GS1b) contain AC elements involved in the transcriptional activation mediated by R2R3-Myb factors. We have examined the capacity of the R2R3-Myb transcription factors Myb1, Myb4 and Myb8 to co-regulate the expression of PAT, PAL and GS1b. Only Myb8 was able to activate the transcription of the three genes. Moreover, the expression of this transcription factor is higher in lignified tissues, in which a high demand for phenylpropanoids exits. In a gain-of-function experiment, we have shown that Myb8 can specifically bind a well-conserved eight-nucleotide-long AC-II element in the promoter regions of PAT, PAL and GS1b, thereby activating their expression. Our results show that Myb8 regulates the expression of these genes involved in phenylalanine metabolism, which is required for channelling photosynthetic carbon to promote wood formation. The co-localization of PAT, PAL, GS1b and MYB8 transcripts in vascular cells further supports this conclusion.

  19. Chromatin landscaping in algae reveals novel regulation pathway for biofuels production

    Energy Technology Data Exchange (ETDEWEB)

    Ngan, Chew Yee; Wong, Chee-Hong; Choi, Cindy; Pratap, Abhishek; Han, James; Wei, Chia-Lin

    2013-02-19

    The diminishing reserve of fossil fuels calls for the development of biofuels. Biofuels are produced from renewable resources, including photosynthetic organisms, generating clean energy. Microalgae is one of the potential feedstock for biofuels production. It grows easily even in waste water, and poses no competition to agricultural crops for arable land. However, little is known about the algae lipid biosynthetic regulatory mechanisms. Most studies relied on the homology to other plant model organisms, in particular Arabidopsis or through low coverage expression analysis to identify key enzymes. This limits the discovery of new components in the biosynthetic pathways, particularly the genetic regulators and effort to maximize the production efficiency of algal biofuels. Here we report an unprecedented and de novo approach to dissect the algal lipid pathways through disclosing the temporal regulations of chromatin states during lipid biosynthesis. We have generated genome wide chromatin maps in chlamydomonas genome using ChIP-seq targeting 7 histone modifications and RNA polymerase II in a time-series manner throughout conditions activating lipid biosynthesis. To our surprise, the combinatory profiles of histone codes uncovered new regulatory mechanism in gene expression in algae. Coupled with matched RNA-seq data, chromatin changes revealed potential novel regulators and candidate genes involved in the activation of lipid accumulations. Genetic perturbation on these candidate regulators further demonstrated the potential to manipulate the regulatory cascade for lipid synthesis efficiency. Exploring epigenetic landscape in microalgae shown here provides powerful tools needed in improving biofuel production and new technology platform for renewable energy generation, global carbon management, and environmental survey.

  20. YBX1 regulates tumor growth via CDC25a pathway in human lung adenocarcinoma

    Science.gov (United States)

    Yu, Wendan; Li, Jinxiu; Tang, Zhipeng; Yu, Zhenlong; Zhao, Lei; Zhang, Yixiang; Wang, Ziyi; Wang, Peng; Li, Yechi; Li, Fengzhou; Sun, Zhe; Xuan, Yang; Tang, Ranran; Deng, Wu-guo; Guo, Wei; Gu, Chundong

    2016-01-01

    Y-box binding protein 1 (YBX1) is involved in the multi-tumor occurrence and development. However, the regulation of YBX1 in lung tumorigenesis and the underlying mechanisms, especially its relationship with CDC25a, was remains unclear. In this study, we analyzed the expression and clinical significance of YBX1 and CDC25a in lung adenocarcinoma and identified their roles in the regulation of lung cancer growth. The retrospective analysis of 116 patients with lung adenocarcinoma indicated that YBX1 was positively correlated with CDC25a expression. The Cox-regression analysis showed only high-ranking TNM stage and low CDC25a expression were an independent risk factor of prognosis in enrolled patients. High expression of YBX1 or CDC25a protein was also observed in lung adenocarcinoma cells compared with HLF cells. ChIP assay demonstrated the binding of endogenous YBX1 to the CDC25a promoter region. Overexpression of exogenous YBX1 up-regulated the expression of the CDC25a promoter-driven luciferase. By contrast, inhibition of YBX1 by siRNA markedly decreased the capability of YBX1 binding to CDC25a promoter in A549 and H322 cells. Inhibition of YBX1 expression also blocked cell cycle progression, suppressed cell proliferation and induced apoptosis via the CDC25a pathway in vitro. Moreover, inhibition of YBX1 by siRNA suppressed tumorigenesis in a xenograft mouse model and down-regulated the expression of YBX1, CDC25a, Ki67 and cleaved caspase 3 in the tumor tissues of mice. Collectively, these results demonstrate inhibition of YBX1 suppressed lung cancer growth partly via the CDC25a pathway and high expression of YBX1/CDC25a predicts poor prognosis in human lung adenocarcinoma. PMID:27384875

  1. Kaempferol Attenuates Cardiac Hypertrophy via Regulation of ASK1/MAPK Signaling Pathway and Oxidative Stress.

    Science.gov (United States)

    Feng, Hong; Cao, Jianlei; Zhang, Guangyu; Wang, Yanggan

    2017-02-20

    Kaempferol has been demonstrated to provide benefits for the treatment of atherosclerosis, coronary heart disease, hyperlipidemia, and diabetes through its antioxidant and anti-inflammatory properties. However, its role in cardiac hypertrophy remains to be elucidated. The aim of our study was to investigate the effects of kaempferol on cardiac hypertrophy and the underlying mechanism. Mice subjected to aorta banding were treated with or without kaempferol (100 mg/kg/d, p. o.) for 6 weeks. Echocardiography was performed to evaluate cardiac function. Mice hearts were collected for pathological observation and molecular mechanism investigation. H9c2 cardiomyocytes were stimulated with or without phenylephrine for in vitro study. Kaempferol significantly attenuated cardiac hypertrophy induced by aorta banding as evidenced by decreased cardiomyocyte areas and interstitial fibrosis, accompanied with improved cardiac functions and decreased apoptosis. The ASK1/MAPK signaling pathways (JNK1/2 and p38) were markedly activated in the aorta banding mouse heart but inhibited by kaempferol treatment. In in vitro experiments, kaempferol also inhibited the activity of ASK1/JNK1/2/p38 signaling pathway and the enlargement of H9c2 cardiomyocytes. Furthermore, our study revealed that kaempferol could protect the mouse heart and H9c2 cells from pathological oxidative stress. Our investigation indicated that treatment with kaempferol protects against cardiac hypertrophy, and its cardioprotection may be partially explained by the inhibition of the ASK1/MAPK signaling pathway and the regulation of oxidative stress.

  2. [Regulation of isoprenoid pathway for enhanced production of linalool in Saccharomyces cerevisiae].

    Science.gov (United States)

    Sun, Mingxue; Liu, Jidong; Du, Guocheng; Zhou, Jingwen; Chen, Jian

    2013-06-01

    Linalool is an important monoterpene, and widely used in food, pharmaceutical and cosmetic industry. The low concentration in plants and the difficulties in extraction restrict its large scale production. Saccharomyces cerevisiae can provide the monoterpene precursor, geranyl diphosphate (GPP) through its endogenous isoprenoid pathway. Therefore, it could be used as the host for monoterpene production. However, the weak metabolic flux through the isoprenoid pathway leads to the insufficient supply of GPP, and results in low monoterpene productivity. In order to increase the metabolic flux, we constructed the integrated expression plasmid pRS305-tHMG1 and free expression plasmid pYLIS-IDI1 to enhance the expression levels of isopentenyl diphosphate isomerase (IDI1) and a truncated 3-hydroxyl-3-methylglutaryl-CoA reductase gene (tHMG1). The two plasmids were separately transformed into S. cerevisiae CEN.PK2-1C, resulting in strains LS01 and LS02. The plasmid pYLIS-IDI1 was further transformed into strain LS01, resulting in strain LS03. GC-MS analysis showed that the linalool concentration was increased by 1.3 times and reached (127.71 +/- 7.68) microg/L. In conclusion, enhancement of the supply of GPP precursors through the regulation of isoprenoid pathway could increase the linalool production in S. cerevisiae.

  3. Flexible metabolic pathway construction using modular and divisible selection gene regulators.

    Science.gov (United States)

    Rugbjerg, Peter; Myling-Petersen, Nils; Sommer, Morten O A

    2015-09-01

    Genetic selections are important to biological engineering. Although selectable traits are limited, currently each trait only permits simultaneous introduction of a single DNA fragment. Complex pathway and strain construction however depends on rapid, combinatorial introduction of many genes that encode putative pathway candidates and homologs. To triple the utility of existing selection genes, we have developed divisible selection in Saccharomyces cerevisiae. Here, independent DNA fragments can be introduced and selected for simultaneously using a set of split hybrid transcription factors composed of parts from Escherichia coli LexA and Herpes simplex VP16 to regulate one single selectable phenotype of choice. Only when co-expressed, these split hybrid transcription factors promote transcription of a selection gene, causing tight selection of transformants containing all desired DNA fragments. Upon transformation, 94% of the selected colonies resulted strictly from transforming all three modules based on ARS/CEN plasmids. Similarly when used for chromosome integration, 95% of the transformants contained all three modules. The divisible selection system acts dominantly and thus expands selection gene utility from one to three without any genomic pre-modifications of the strain. We demonstrate the approach by introducing the fungal rubrofusarin polyketide pathway at a gene load of 11 kb distributed on three different plasmids, using a single selection trait and one yeast transformation step. By tripling the utility of existing selection genes, the employment of divisible selection improves flexibility and freedom in the strain engineering process.

  4. PORCN moonlights in a Wnt-independent pathway that regulates cancer cell proliferation.

    Directory of Open Access Journals (Sweden)

    Tracy M Covey

    Full Text Available Porcupine (PORCN is a membrane-bound O-acyl transferase that is required for the palmitoylation of Wnt proteins, and that is essential in diverse Wnt pathways for Wnt-Wntless (WLS binding, Wnt secretion, and Wnt signaling activity. We tested if PORCN was required for the proliferation of transformed cells. Knockdown of PORCN by multiple independent siRNAs results in a cell growth defect in a subset of epithelial cancer cell lines. The growth defect is transformation-dependent in human mammary epithelial (HMEC cells. Additionally, inducible PORCN knockdown by two independent shRNAs markedly reduces the growth of established MDA-MB-231 cancers in orthotopic xenografts in immunodeficient mice. Unexpectedly, the proliferation defect resulting from loss of PORCN occurs in a Wnt-independent manner, as it is rescued by re-expression of catalytically inactive PORCN, and is not seen after RNAi-mediated knockdown of the Wnt carrier protein WLS, nor after treatment with the PORCN inhibitor IWP. Consistent with a role in a Wnt-independent pathway, knockdown of PORCN regulates a distinct set of genes that are not altered by other inhibitors of Wnt signaling. PORCN protein thus appears to moonlight in a novel signaling pathway that is rate-limiting for cancer cell growth and tumorigenesis independent of its enzymatic function in Wnt biosynthesis and secretion.

  5. A Wnt-Frz/Ror-Dsh pathway regulates neurite outgrowth in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Song Song

    2010-08-01

    Full Text Available One of the challenges to understand the organization of the nervous system has been to determine how axon guidance molecules govern axon outgrowth. Through an unbiased genetic screen, we identified a conserved Wnt pathway which is crucial for anterior-posterior (A/P outgrowth of neurites from RME head motor neurons in Caenorhabditis elegans. The pathway is composed of the Wnt ligand CWN-2, the Frizzled receptors CFZ-2 and MIG-1, the co-receptor CAM-1/Ror, and the downstream component Dishevelled/DSH-1. Among these, CWN-2 acts as a local attractive cue for neurite outgrowth, and its activity can be partially substituted with other Wnts, suggesting that spatial distribution plays a role in the functional specificity of Wnts. As a co-receptor, CAM-1 functions cell-autonomously in neurons and, together with CFZ-2 and MIG-1, transmits the Wnt signal to downstream effectors. Yeast two-hybrid screening identified DSH-1 as a binding partner for CAM-1, indicating that CAM-1 could facilitate CWN-2/Wnt signaling by its physical association with DSH-1. Our study reveals an important role of a Wnt-Frz/Ror-Dsh pathway in regulating neurite A/P outgrowth.

  6. A SNX10/V-ATPase pathway regulates ciliogenesis in vitro and in vivo

    Institute of Scientific and Technical Information of China (English)

    Yanaun Chen; Shuo Lin; Xiaodong Shu; Duanqing Pei; Bin Wu; Liangliang Xu; Huapeng Li; Jianhong Xia; Wenguang Yin; Zhuo Li; Dawei Shi; Song Li

    2012-01-01

    Sorting nexins (SNXs) are phosphoinositide-binding proteins implicated in the sorting of various membrane proteins in vitro,but the in vivo functions of them remain largely unknown.We reported previously that SNX10 is a unique member of the SNX family genes in that it has vacuolation activity in cells.We investigate the biological function of SNX10 by loss-of-function assay in this study and demonstrate that SNX10 is required for the formation of primary cilia in cultured cells.In zebrafish,SNX10 is involved in ciliogenesis in the Kupffer's vesicle and essential for left-right patterning of visceral organs.Mechanistically,SNX10 interacts with V-ATPase complex and targets it to the centrosome where ciliogenesis is initiated.Like SNX10,V-ATPase regulates ciliogenesis in vitro and in vivo and does so synergistically with SNX10.We further discover that SNX10 and V-ATPase regulate the ciliary trafficking of Rab8a,which is a critical regulator of ciliary membrane extension.These results identify an SNX10/V-ATPaseregulated vesicular trafficking pathway that is crucial for ciliogenesis,and reveal that SNX10/V-ATPase,through the regulation of cilia formation in various organs,play an essential role during early embryonic development.

  7. The mitochondrial Ca2+ uniporter: regulation by auxiliary subunits and signal transduction pathways.

    Science.gov (United States)

    Jhun, Bong Sook; Mishra, Jyotsna; Monaco, Sarah; Fu, Deming; Jiang, Wenmin; Sheu, Shey-Shing; O-Uchi, Jin

    2016-07-01

    Mitochondrial Ca(2+) homeostasis, the Ca(2+) influx-efflux balance, is responsible for the control of numerous cellular functions, including energy metabolism, generation of reactive oxygen species, spatiotemporal dynamics of Ca(2+) signaling, and cell growth and death. Recent discovery of the molecular identity of the mitochondrial Ca(2+) uniporter (MCU) provides new possibilities for application of genetic approaches to study the mitochondrial Ca(2+) influx mechanism in various cell types and tissues. In addition, the subsequent discovery of various auxiliary subunits associated with MCU suggests that mitochondrial Ca(2+) uptake is not solely regulated by a single protein (MCU), but likely by a macromolecular protein complex, referred to as the MCU-protein complex (mtCUC). Moreover, recent reports have shown the potential role of MCU posttranslational modifications in the regulation of mitochondrial Ca(2+) uptake through mtCUC. These observations indicate that mtCUCs form a local signaling complex at the inner mitochondrial membrane that could significantly regulate mitochondrial Ca(2+) handling, as well as numerous mitochondrial and cellular functions. In this review we discuss the current literature on mitochondrial Ca(2+) uptake mechanisms, with a particular focus on the structure and function of mtCUC, as well as its regulation by signal transduction pathways, highlighting current controversies and discrepancies.

  8. Regulation of interferon pathway in 2-methoxyestradiol-treated osteosarcoma cells

    Directory of Open Access Journals (Sweden)

    Wimbauer Fritz

    2012-03-01

    Full Text Available Abstract Background Osteosarcoma is a bone tumor that often affects children and young adults. Although a combination of surgery and chemotherapy has improved the survival rate in the past decades, local recurrence and metastases still develop in 40% of patients. A definite therapy is yet to be determined for osteosarcoma. Anti- tumor compound and a metabolite of estrogen, 2-methoxyestradiol (2-ME induces cell death in osteosarcoma cells. In this report, we have investigated whether interferon (IFN pathway is involved in 2-ME-induced anti-tumor effects in osteosarcoma cells. Methods 2-ME effects on IFN mRNA levels were determined by Real time PCR analysis. Transient transfections followed by reporter assays were used for investigating 2-ME effects on IFN-pathway. Western blot analyses were used to measure protein and phosphorylation levels of IFN-regulated eukaryotic initiation factor-2 alpha (eIF-2α. Results 2-ME regulates IFN and IFN-mediated effects in osteosarcoma cells. 2 -ME induces IFN gene activity and expression in osteosarcoma cells. 2-ME treatment induced IFN-stimulated response element (ISRE sequence-dependent transcription and gamma-activated sequence (GAS-dependent transcription in several osteosarcoma cells. Whereas, 2-ME did not affect IFN gene and IFN pathways in normal primary human osteoblasts (HOB. 2-ME treatment increased the phosphorylation of eIF-2α in osteosarcoma cells. Furthermore, analysis of osteosarcoma tissues shows that the levels of phosphorylated form of eIF-2α are decreased in tumor compared to normal controls. Conclusions 2-ME treatment triggers the induction and activity of IFN and IFN pathway genes in 2-ME-sensitive osteosarcoma tumor cells but not in 2-ME-resistant normal osteoblasts. In addition, IFN-signaling is inhibited in osteosarcoma patients. Thus, IFN pathways play a role in osteosarcoma and in 2-ME-mediated anti-proliferative effects, and therefore targeted induction of IFN signaling could lead

  9. BMP signaling negatively regulates bone mass through sclerostin by inhibiting the canonical Wnt pathway.

    Science.gov (United States)

    Kamiya, Nobuhiro; Ye, Ling; Kobayashi, Tatsuya; Mochida, Yoshiyuki; Yamauchi, Mitsuo; Kronenberg, Henry M; Feng, Jian Q; Mishina, Yuji

    2008-11-01

    Bone morphogenetic proteins (BMPs) are known to induce ectopic bone. However, it is largely unknown how BMP signaling in osteoblasts directly regulates endogenous bone. This study investigated the mechanism by which BMP signaling through the type IA receptor (BMPR1A) regulates endogenous bone mass using an inducible Cre-loxP system. When BMPR1A in osteoblasts was conditionally disrupted during embryonic bone development, bone mass surprisingly was increased with upregulation of canonical Wnt signaling. Although levels of bone formation markers were modestly reduced, levels of resorption markers representing osteoclastogenesis were severely reduced, resulting in a net increase in bone mass. The reduction of osteoclastogenesis was primarily caused by Bmpr1a-deficiency in osteoblasts, at least through the RANKL-OPG pathway. Sclerostin (Sost) expression was downregulated by about 90% and SOST protein was undetectable in osteoblasts and osteocytes, whereas the Wnt signaling was upregulated. Treatment of Bmpr1a-deficient calvariae with sclerostin repressed the Wnt signaling and restored normal bone morphology. By gain of Smad-dependent BMPR1A signaling in mice, Sost expression was upregulated and osteoclastogenesis was increased. Finally, the Bmpr1a-deficient bone phenotype was rescued by enhancing BMPR1A signaling, with restoration of osteoclastogenesis. These findings demonstrate that BMPR1A signaling in osteoblasts restrain endogenous bone mass directly by upregulating osteoclastogenesis through the RANKL-OPG pathway, or indirectly by downregulating canonical Wnt signaling through sclerostin, a Wnt inhibitor and a bone mass mediator.

  10. Identification and Characterization of Multiple Intermediate Alleles of the Key Genes Regulating Brassinosteroid Biosynthesis Pathways

    Science.gov (United States)

    Du, Junbo; Zhao, Baolin; Sun, Xin; Sun, Mengyuan; Zhang, Dongzhi; Zhang, Shasha; Yang, Wenyu

    2017-01-01

    Most of the early identified brassinosteroid signaling and biosynthetic mutants are null mutants, exhibiting extremely dwarfed phenotypes and male sterility. These null mutants are usually unable to be directly transformed via a routinely used Agrobacterium-mediated gene transformation system and therefore are less useful for genetic characterization of the brassinosteroid (BR)-related pathways. Identification of intermediate signaling mutants such as bri1–5 and bri1–9 has contributed drastically to the elucidation of BR signaling pathway using both genetic and biochemical approaches. However, intermediate mutants of key genes regulating BR biosynthesis have seldom been reported. Here we report identification of several intermediate BR biosynthesis mutants mainly resulted from leaky transcriptions due to the insertions of T-DNAs in the introns. These mutants are semi-dwarfed and fertile and capable to be transformed. These intermediate mutants could be useful tools for future discovery and analyses of novel components regulating BR biosynthesis and catabolism via genetic modifier screen. PMID:28138331

  11. 3D culture broadly regulates tumor cell hypoxia response and angiogenesis via pro-inflammatory pathways.

    Science.gov (United States)

    DelNero, Peter; Lane, Maureen; Verbridge, Scott S; Kwee, Brian; Kermani, Pouneh; Hempstead, Barbara; Stroock, Abraham; Fischbach, Claudia

    2015-07-01

    Oxygen status and tissue dimensionality are critical determinants of tumor angiogenesis, a hallmark of cancer and an enduring target for therapeutic intervention. However, it is unclear how these microenvironmental conditions interact to promote neovascularization, due in part to a lack of comprehensive, unbiased data sets describing tumor cell gene expression as a function of oxygen levels within three-dimensional (3D) culture. Here, we utilized alginate-based, oxygen-controlled 3D tumor models to study the interdependence of culture context and the hypoxia response. Microarray gene expression analysis of tumor cells cultured in 2D versus 3D under ambient or hypoxic conditions revealed striking interdependence between culture dimensionality and hypoxia response, which was mediated in part by pro-inflammatory signaling pathways. In particular, interleukin-8 (IL-8) emerged as a major player in the microenvironmental regulation of the hypoxia program. Notably, this interaction between dimensionality and oxygen status via IL-8 increased angiogenic sprouting in a 3D endothelial invasion assay. Taken together, our data suggest that pro-inflammatory pathways are critical regulators of tumor hypoxia response within 3D environments that ultimately impact tumor angiogenesis, potentially providing important therapeutic targets. Furthermore, these results highlight the importance of pathologically relevant tissue culture models to study the complex physical and chemical processes by which the cancer microenvironment mediates new vessel formation.

  12. The Drosophila Perlecan gene trol regulates multiple signaling pathways in different developmental contexts

    Directory of Open Access Journals (Sweden)

    Perry Trinity L

    2007-11-01

    signaling contexts. These studies also highlight the fact that Trol function is not dedicated to a single molecular mechanism, but is capable of regulating different growth factor pathways depending on the cell-type and event underway.

  13. Mechanisms regulating neuronal excitability and seizure development following mTOR pathway hyperactivation

    Directory of Open Access Journals (Sweden)

    Candi L LaSarge

    2014-03-01

    Full Text Available The PI3K/PTEN-mTOR pathway regulates a variety of neuronal functions, including cell proliferation, survival, growth and plasticity. Dysregulation of the pathway is implicated in the development of both genetic and acquired epilepsies. Indeed, several causal mutations have been identified in patients with epilepsy, the most prominent of these being mutations in phosphatase and tensin homologue (PTEN and tuberal sclerosis complexes 1 and 2 (TSC1, TSC2. These genes act as negative regulators of mTOR signaling, and mutations lead to hyperactivation of the pathway. Animal models deleting PTEN, TSC1 and TSC2 consistently produce epilepsy phenotypes, demonstrating that increased mTOR signaling can provoke neuronal hyperexcitability. Given the broad range of changes induced by altered mTOR signaling, however, the mechanisms underlying seizure development in these animals remain uncertain. In transgenic mice, cell populations with hyperactive mTOR have many structural abnormalities that support recurrent circuit formation, including somatic and dendritic hypertrophy, aberrant basal dendrites, and enlargement of axon tracts. At the functional level, mTOR hyperactivation is commonly, but not always, associated with enhanced synaptic transmission and plasticity. Moreover, these populations of abnormal neurons can affect the larger network, inducing secondary changes that may explain paradoxical findings reported between cell and network functioning in different models or at different developmental time points. Here, we review the animal literature examining the link between mTOR hyperactivation and epileptogenesis, emphasizing the impact of enhanced mTOR signaling on neuronal form and function.

  14. The canonical Notch pathway effector RBP-J regulates neuronal plasticity and expression of GABA transporters in hippocampal networks.

    Science.gov (United States)

    Liu, Shuxi; Wang, Yue; Worley, Paul F; Mattson, Mark P; Gaiano, Nicholas

    2015-05-01

    Activation of the Notch pathway in neurons is essential for learning and memory in various species from invertebrates to mammals. However, it remains unclear how Notch signaling regulates neuronal plasticity, and whether the transcriptional regulator and canonical pathway effector RBP-J plays a role. Here, we report that conditional disruption of RBP-J in the postnatal hippocampus leads to defects in long-term potentiation, long-term depression, and in learning and memory. Using gene expression profiling and chromatin immunoprecipitation, we identified two GABA transporters, GAT2 and BGT1, as putative Notch/RBP-J pathway targets, which may function downstream of RBP-J to limit the accumulation of GABA in the Schaffer collateral pathway. Our results reveal an essential role for canonical Notch/RBP-J signaling in hippocampal synaptic plasticity and suggest that role, at least in part, is mediated by the regulation of GABAergic signaling.

  15. TRPM7 channels regulate glioma stem cell through STAT3 and Notch signaling pathways.

    Science.gov (United States)

    Liu, Mingli; Inoue, Koichi; Leng, Tiandong; Guo, Shanchun; Xiong, Zhi-gang

    2014-12-01

    Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in adults with median survival time of 14.6 months. A small fraction of cancer stem cells (CSC) initiate and maintain tumors thus driving glioma tumorigenesis and being responsible for resistance to classical chemo- and radio-therapies. It is desirable to identify signaling pathways related to CSC to develop novel therapies to selectively target them. Transient receptor potential cation channel, subfamily M, member 7, also known as TRPM7 is a ubiquitous, Ca(2+) and Mg(2+) permeable ion channels that are special in being both an ion channel and a serine/threonine kinase. In studies of glioma cells silenced for TRPM7, we demonstrated that Notch (Notch1, JAG1, Hey2, and Survivin) and STAT3 pathways are down regulated in glioma cells grown in monolayer. Furthermore, phospho-STAT3, Notch target genes and CSC markers (ALDH1 and CD133) were significantly higher in spheroid glioma CSCs when compared with monolayer cultures. The results further show that tyrosine-phosphorylated STAT3 binds and activates the ALDH1 promoters in glioma cells. We found that TRMP7-induced upregulation of ALDH1 expression is associated with increases in ALDH1 activity and is detectable in stem-like cells when expanded as spheroid CSCs. Finally, TRPM7 promotes proliferation, migration and invasion of glioma cells. These demonstrate that TRPM7 activates JAK2/STAT3 and/or Notch signaling pathways and leads to increased cell proliferation and migration. These findings for the first time demonstrates that TRPM7 (1) activates a previously unrecognized STAT3→ALDH1 pathway, and (2) promotes the induction of ALDH1 activity in glioma cells.

  16. The regulation of the oxidative phase of the pentose phosphate pathway: new answers to old problems.

    Science.gov (United States)

    Barcia-Vieitez, Ramiro; Ramos-Martínez, Juan Ignacio

    2014-11-01

    There is a paradox in the oxidizing phase of the phosphate pentose pathway that has not yet been solved. The flow through the pathway is reduced in basal conditions; however, it must rise notably when a NADPH supplement is required. The paradox consists of the strong inhibition that the NADPH exerts on the both dehydrogenases of the pathway, especially on the regulating enzyme glucose-6-phosphate dehydrogenase (G6PD). Theoretically, in anabolic situations, the increase of gene expression of G6PD and 6-phosphogluconate dehydrogenase can induce a rise in the production of NADPH, which would cause the immediate inhibition of the enzyme and a drastic flow reduction. However, increasing the flow through oxidative phase of the pentose phosphate pathway (OPPP) has been experimentally demonstrated in many physiological states. However, this situation will be resolved if the NADPH metabolized or otherwise sufficient NADPH is sequestered to relax the inhibition of the dehydrogenases of OPPP and to maintain high ratio of NADPH/NADP(+) needed to ensure the reducing environment of the cell cytoplasm and the contribution of NADPH for anabolic processes. In 1974, the presence of a protein capable of reversing the inhibition of G6PD by NADPH was detected; however, to date, this paradox remains undisclosed. This review deals with the possibility that such reverting action might be similar to the activity of a protein named HSCARG, which is responsible for the abduction of NADPH, thus keeping a portion of the coenzyme away from the catalytic action and, simultaneously, the immune response through the NF-κB (nuclear factor kappa light-chain enhancer of activated B cells) system. The model has many similarities with the hypothesis proposed some 40 years back on the reversion of G6PD inhibition by NADPH.

  17. The DAF-7/TGF-β signaling pathway regulates abundance of the Caenorhabditis elegans glutamate receptor GLR-1.

    Science.gov (United States)

    McGehee, Annette M; Moss, Benjamin J; Juo, Peter

    2015-07-01

    Transforming growth factor-β (TGF-β) family signaling pathways have roles in both neuronal development and the regulation of synaptic function. Here we identify a novel role for the Caenorhabditis elegans DAF-7/TGF-β signaling pathway in the regulation of the AMPA-type glutamate receptor GLR-1. We found that the abundance of GLR-1 increases at synapses in the ventral nerve cord (VNC) of animals with loss-of-function mutations in multiple DAF-7/TGF-β pathway components including the TGF-β ligand DAF-7, the type I receptor DAF-1, and the Smads DAF-8 and DAF-14. The GLR-1 defect can be rescued by expression of daf-8 specifically in glr-1-expressing interneurons. The effect on GLR-1 was specific for the DAF-7 pathway because mutations in the DBL-1/TGF-β family pathway did not increase GLR-1 levels in the VNC. Immunoblot analysis indicates that total levels of GLR-1 protein are increased in neurons of DAF-7/TGF-β pathway mutants. The increased abundance of GLR-1 in the VNC of daf-7 pathway mutants is dependent on the transcriptional regulator DAF-3/Smad suggesting that DAF-3-dependent transcription controls GLR-1 levels. Furthermore, we found that glr-1 transcription is increased in daf-7 mutants based on a glr-1 transcriptional reporter. Together these results suggest that the DAF-7/TGF-β signaling pathway functions in neurons and negatively regulates the abundance of GLR-1, in part, by controlling transcription of the receptor itself. Finally, DAF-7/TGF-β pathway mutants exhibit changes in spontaneous locomotion that are dependent on endogenous GLR-1 and consistent with increased glutamatergic signaling. These results reveal a novel mechanism by which TGF-β signaling functions in the nervous system to regulate behavior.

  18. The Che4 pathway of Myxococcus xanthus regulates type IV pilus-mediated motility.

    Science.gov (United States)

    Vlamakis, Hera C; Kirby, John R; Zusman, David R

    2004-06-01

    Myxococcus xanthus co-ordinates cell movement during its complex life cycle using multiple chemotaxis-like signal transduction pathways. These pathways regulate both type IV pilus-mediated social (S) motility and adventurous (A) motility. During a search for new chemoreceptors, we identified the che4 operon, which encodes homologues to a MCP (methyl-accepting chemotaxis protein), two CheWs, a hybrid CheA-CheY, a response regulator and a CheR. Deletion of the che4 operon did not cause swarming or developmental defects in either the wild-type (A(+)S(+)) strain or in a strain sustaining only A motility (A(+)S(-)). However, in a strain displaying only S motility (A(-)S(+)), deletion of the che4 operon or the gene encoding the response regulator, cheY4, caused enhanced vegetative swarming and prevented aggregation and sporulation. In contrast, deletion of mcp4 caused reduced vegetative swarming and enhanced development compared with the parent strain. Single-cell analysis of the motility of the A(-)S(+) parent strain revealed a previously unknown inverse correlation between velocity and reversal frequency. Thus, cells that moved at higher velocities showed a reduced reversal frequency. This co-ordination of reversal frequency and velocity was lost in the mcp4 and cheY4 mutants. The structural components of the S motility apparatus were unaffected in the che4 mutants, suggesting that the Che4 system affects reversal frequency of cells by modulating the function of the type IV pilus.

  19. LAPTM5 protein is a positive regulator of proinflammatory signaling pathways in macrophages.

    Science.gov (United States)

    Glowacka, Wioletta K; Alberts, Philipp; Ouchida, Rika; Wang, Ji-Yang; Rotin, Daniela

    2012-08-10

    LAPTM5 (lysosomal-associated protein transmembrane 5) is a protein that is preferentially expressed in immune cells, and it interacts with the Nedd4 family of ubiquitin ligases. Recent studies in T and B cells identified LAPTM5 as a negative regulator of T and B cell receptor levels at the plasma membrane. Here we investigated the function of LAPTM5 in macrophages. We demonstrate that expression of LAPTM5 is required for the secretion of proinflammatory cytokines in response to Toll-like receptor ligands. We also show that RAW264.7 cells knocked down for LAPTM5 or macrophages from LAPTM5(-/-) mice exhibit reduced activation of NF-κB and MAPK signaling pathways mediated by the TNF receptor, as well as multiple pattern recognition receptors in various cellular compartments. TNF stimulation of LAPTM5-deficient macrophages leads to reduced ubiquitination of RIP1 (receptor-interacting protein 1), suggesting a role for LAPTM5 at the receptor-proximate level. Interestingly, we find that macrophages from LAPTM5(-/-) mice display up-regulated levels of A20, a ubiquitin-editing enzyme responsible for deubiquitination of RIP1 and subsequent termination of NF-κB activation. Our studies thus indicate that, in contrast to its negative role in T and B cell activation, LAPTM5 acts as a positive modulator of inflammatory signaling pathways and hence cytokine secretion in macrophages. They also highlight a role for the endosomal/lysosomal system in regulating signaling via cytokine and pattern recognition receptors.

  20. The Strip-Hippo Pathway Regulates Synaptic Terminal Formation by Modulating Actin Organization at the Drosophila Neuromuscular Synapses

    Directory of Open Access Journals (Sweden)

    Chisako Sakuma

    2016-08-01

    Full Text Available Synapse formation requires the precise coordination of axon elongation, cytoskeletal stability, and diverse modes of cell signaling. The underlying mechanisms of this interplay, however, remain unclear. Here, we demonstrate that Strip, a component of the striatin-interacting phosphatase and kinase (STRIPAK complex that regulates these processes, is required to ensure the proper development of synaptic boutons at the Drosophila neuromuscular junction. In doing so, Strip negatively regulates the activity of the Hippo (Hpo pathway, an evolutionarily conserved regulator of organ size whose role in synapse formation is currently unappreciated. Strip functions genetically with Enabled, an actin assembly/elongation factor and the presumptive downstream target of Hpo signaling, to modulate local actin organization at synaptic termini. This regulation occurs independently of the transcriptional co-activator Yorkie, the canonical downstream target of the Hpo pathway. Our study identifies a previously unanticipated role of the Strip-Hippo pathway in synaptic development, linking cell signaling to actin organization.

  1. The yield of essential oils in Melaleuca alternifolia (Myrtaceae is regulated through transcript abundance of genes in the MEP pathway.

    Directory of Open Access Journals (Sweden)

    Hamish Webb

    Full Text Available Medicinal tea tree (Melaleuca alternifolia leaves contain large amounts of an essential oil, dominated by monoterpenes. Several enzymes of the chloroplastic methylerythritol phosphate (MEP pathway are hypothesised to act as bottlenecks to the production of monoterpenes. We investigated, whether transcript abundance of genes encoding for enzymes of the MEP pathway were correlated with foliar terpenes in M. alternifolia using a population of 48 individuals that ranged in their oil concentration from 39 -122 mg x g DM(-1. Our study shows that most genes in the MEP pathway are co-regulated and that the expression of multiple genes within the MEP pathway is correlated with oil yield. Using multiple regression analysis, variation in expression of MEP pathway genes explained 87% of variation in foliar monoterpene concentrations. The data also suggest that sesquiterpenes in M. alternifolia are synthesised, at least in part, from isopentenyl pyrophosphate originating from the plastid via the MEP pathway.

  2. The Ras/Raf/MEK/extracellular signal-regulated kinase pathway induces autocrine-paracrine growth inhibition via the leukemia inhibitory factor/JAK/STAT pathway.

    Science.gov (United States)

    Park, Jong-In; Strock, Christopher J; Ball, Douglas W; Nelkin, Barry D

    2003-01-01

    Sustained activation of the Ras/Raf/MEK/extracellular signal-regulated kinase (ERK) pathway can lead to cell cycle arrest in many cell types. We have found, with human medullary thyroid cancer (MTC) cells, that activated Ras or c-Raf-1 can induce growth arrest by producing and secreting an autocrine-paracrine factor. This protein was purified from cell culture medium conditioned by Raf-activated MTC cells and was identified by mass spectrometry as leukemia inhibitory factor (LIF). LIF expression upon Raf activation and subsequent activation of JAK-STAT3 was also observed in small cell lung carcinoma cells, suggesting that this autocrine-paracrine signaling may be a common response to Ras/Raf activation. LIF was sufficient to induce growth arrest and differentiation of MTC cells. This effect was mediated through the gp130/JAK/STAT3 pathway, since anti-gp130 blocking antibody or dominant-negative STAT3 blocked the effects of LIF. Thus, LIF expression provides a novel mechanism allowing Ras/Raf signaling to activate the JAK-STAT3 pathway. In addition to this cell-extrinsic growth inhibitory pathway, we find that the Ras/Raf/MEK/ERK pathway induces an intracellular growth inhibitory signal, independent of the LIF/JAK/STAT3 pathway. Therefore, activation of the Ras/Raf/MEK/ERK pathway can lead to growth arrest and differentiation via at least two different signaling pathways. This use of multiple pathways may be important for "fail-safe" induction and maintenance of cell cycle arrest.

  3. Pds5 regulators segregate cohesion and condensation pathways in Saccharomyces cerevisiae.

    Science.gov (United States)

    Tong, Kevin; Skibbens, Robert V

    2015-06-02

    Cohesins are required both for the tethering together of sister chromatids (termed cohesion) and subsequent condensation into discrete structures-processes fundamental for faithful chromosome segregation into daughter cells. Differentiating between cohesin roles in cohesion and condensation would provide an important advance in studying chromatin metabolism. Pds5 is a cohesin-associated factor that is essential for both cohesion maintenance and condensation. Recent studies revealed that ELG1 deletion suppresses the temperature sensitivity of pds5 mutant cells. However, the mechanisms through which Elg1 may regulate cohesion and condensation remain unknown. Here, we report that ELG1 deletion from pds5-1 mutant cells results in a significant rescue of cohesion, but not condensation, defects. Based on evidence that Elg1 unloads the DNA replication clamp PCNA from DNA, we tested whether PCNA overexpression would similarly rescue pds5-1 mutant cell cohesion defects. The results indeed reveal that elevated levels of PCNA rescue pds5-1 temperature sensitivity and cohesion defects, but do not rescue pds5-1 mutant cell condensation defects. In contrast, RAD61 deletion rescues the condensation defect, but importantly, neither the temperature sensitivity nor cohesion defects exhibited by pds5-1 mutant cells. In combination, these findings reveal that cohesion and condensation are separable pathways and regulated in nonredundant mechanisms. These results are discussed in terms of a new model through which cohesion and condensation are spatially regulated.

  4. hCLP46 regulates U937 cell proliferation via Notch signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Wenzhan; Du, Jie; Chu, Qiaoyun [College of Life Science, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Youxin [School of Public Health and Family Medicine, Capital Medical University, Beijing 100069 (China); Liu, Lixin [College of Life Science, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Song, Manshu [School of Public Health and Family Medicine, Capital Medical University, Beijing 100069 (China); Wang, Wei, E-mail: wei6014@yahoo.com [College of Life Science, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); School of Public Health and Family Medicine, Capital Medical University, Beijing 100069 (China)

    2011-04-29

    Highlights: {yields} Knock down of hCLP46 by RNAi impairs mammalian Notch signaling. {yields} hCLP46 affects neither cell surface Notch1 expression nor ligand-receptor binding. {yields} Knock down of hCLP46 inhibits U937 cell-growth by up-regulation of CDKN1B. -- Abstract: Human CAP10-like protein 46 kDa (hCLP46) is the homolog of Rumi, which is the first identified protein O-glucosyltransferase that modifies Notch receptor in Drosophila. Dysregulation of hCLP46 occurs in many hematologic diseases, but the role of hCLP46 remains unclear. Knockdown of hCLP46 by RNA interference resulted in decreased protein levels of endogenous Notch1, Notch intracellular domain (NICD) and Notch target gene Hes-1, suggesting the impairment of the Notch signaling. However, neither cell surface Notch expression nor ligand binding activities were affected. In addition, down-regulated expression of hCLP46 inhibited the proliferation of U937 cells, which was correlated with increased cyclin-dependent kinase inhibitor (CDKI) CDKN1B (p27) and decreased phosphorylation of retinoblastoma (RB) protein. We showed that lack of hCLP46 results in impaired ligand induced Notch activation in mammalian cell, and hCLP46 regulates the proliferation of U937 cell through CDKI-RB signaling pathway, which may be important for the pathogenesis of leukemia.

  5. Lxr regulates lipid metabolic and visual perception pathways during zebrafish development.

    Science.gov (United States)

    Pinto, Caroline Lucia; Kalasekar, Sharanya Maanasi; McCollum, Catherine W; Riu, Anne; Jonsson, Philip; Lopez, Justin; Swindell, Eric C; Bouhlatouf, Abdel; Balaguer, Patrick; Bondesson, Maria; Gustafsson, Jan-Åke

    2016-01-05

    The Liver X Receptors (LXRs) play important roles in multiple metabolic pathways, including fatty acid, cholesterol, carbohydrate and energy metabolism. To expand the knowledge of the functions of LXR signaling during embryonic development, we performed a whole-genome microarray analysis of Lxr target genes in zebrafish larvae treated with either one of the synthetic LXR ligands T0901317 or GW3965. Assessment of the biological processes enriched by differentially expressed genes revealed a prime role for Lxr in regulating lipid metabolic processes, similarly to the function of LXR in mammals. In addition, exposure to the Lxr ligands induced changes in expression of genes in the neural retina and lens of the zebrafish eye, including the photoreceptor guanylate cyclase activators and lens gamma crystallins, suggesting a potential novel role for Lxr in modulating the transcription of genes associated with visual function in zebrafish. The regulation of expression of metabolic genes was phenotypically reflected in an increased absorption of yolk in the zebrafish larvae, and changes in the expression of genes involved in visual perception were associated with morphological alterations in the retina and lens of the developing zebrafish eye. The regulation of expression of both lipid metabolic and eye specific genes was sustained in 1 month old fish. The transcriptional networks demonstrated several conserved effects of LXR activation between zebrafish and mammals, and also identified potential novel functions of Lxr, supporting zebrafish as a promising model for investigating the role of Lxr during development.

  6. Perturbation-based analysis and modeling of combinatorial regulation in the yeast sulfur assimilation pathway.

    Science.gov (United States)

    McIsaac, R Scott; Petti, Allegra A; Bussemaker, Harmen J; Botstein, David

    2012-08-01

    In yeast, the pathways of sulfur assimilation are combinatorially controlled by five transcriptional regulators (three DNA-binding proteins [Met31p, Met32p, and Cbf1p], an activator [Met4p], and a cofactor [Met28p]) and a ubiquitin ligase subunit (Met30p). This regulatory system exerts combinatorial control not only over sulfur assimilation and methionine biosynthesis, but also on many other physiological functions in the cell. Recently we characterized a gene induction system that, upon the addition of an inducer, results in near-immediate transcription of a gene of interest under physiological conditions. We used this to perturb levels of single transcription factors during steady-state growth in chemostats, which facilitated distinction of direct from indirect effects of individual factors dynamically through quantification of the subsequent changes in genome-wide patterns of gene expression. We were able to show directly that Cbf1p acts sometimes as a repressor and sometimes as an activator. We also found circumstances in which Met31p/Met32p function as repressors, as well as those in which they function as activators. We elucidated and numerically modeled feedback relationships among the regulators, notably feedforward regulation of Met32p (but not Met31p) by Met4p that generates dynamic differences in abundance that can account for the differences in function of these two proteins despite their identical binding sites.

  7. The regulated secretory pathway and human disease: insights from gene variants and single nucleotide polymorphisms

    Directory of Open Access Journals (Sweden)

    Stephen eSalton

    2013-08-01

    Full Text Available The regulated secretory pathway provides critical control of peptide, growth factor, and hormone release from neuroendocrine and endocrine cells, and neurons, maintaining physiological homeostasis. Propeptides and prohormones are packaged into dense core granules (DCGs, where they frequently undergo tissue-specific processing as the DCG matures. Proteins of the granin family are DCG components, and although their function is not fully understood, data suggest they are involved in DCG formation and regulated protein/peptide secretion, in addition to their role as precursors of bioactive peptides. Association of gene variation, including single nucleotide polymorphisms (SNPs, with neuropsychiatric, endocrine and metabolic diseases, has implicated specific secreted proteins and peptides in disease pathogenesis. For example, a SNP at position 196 (G/A of the human brain-derived neurotrophic factor (BDNF gene dysregulates protein processing and secretion and leads to cognitive impairment. This suggests more generally that variants identified in genes encoding secreted growth factors, peptides, hormones, and proteins involved in DCG biogenesis, protein processing, and the secretory apparatus, could provide insight into the process of regulated secretion as well as disorders that result when it is impaired.

  8. REGγ regulates ERα degradation via ubiquitin–proteasome pathway in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Fan; Liang, Yan [Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Bi, Jiong [Laboratory of General Surgery, First Affiliated Hospital, Sun Yet-sen University, Guangzhou 510080 (China); Chen, Li; Zhang, Fan [Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Cui, Youhong [Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Jiang, Jun, E-mail: jcbd@medmail.com.cn [Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China)

    2015-01-02

    Highlights: • High expression of REGγ is correlated with ERα status and poor clinical features. • Cell growth, mobility and invasion are significantly impaired by REGγ knockdown. • REGγ indirectly regulates ERα protein expression. - Abstract: REGγ is a proteasome coactivator which regulates proteolytic activity in eukaryotic cells. Abundant lines of evidence have showed that REGγ is over expressed in a number of human carcinomas. However, its precise role in the pathogenesis of cancer is still unclear. In this study, by examining 200 human breast cancer specimens, we demonstrated that REGγ was highly expressed in breast cancers, and the expression of REGγ was positively correlated with breast cancer patient estrogen receptor alpha (ERα) status. Moreover, the expression of REGγ was found positively associated with poor clinical features and low survival rates in ERα positive breast cancer patients. Further cell culture studies using MCF7 and BT474 breast cancer cell lines showed that cell proliferation, motility, and invasion capacities were decreased significantly by REGγ knockdown. Lastly, we demonstrated that REGγ indirectly regulates the degradation of ERα protein via ubiquitin–proteasome pathway. In conclusion, our findings provide the evidence that REGγ expression was positively correlated with ERα status and poor clinical prognosis in ERα positive breast cancer patients. As well, we disclose a new connection between the two molecules that are both highly expressed in most breast cancer cases.

  9. sli-3 negatively regulates the LET-23/epidermal growth factor receptor-mediated vulval induction pathway in Caenorhabditis elegans.

    Science.gov (United States)

    Gupta, Bhagwati P; Liu, Jing; Hwang, Byung J; Moghal, Nadeem; Sternberg, Paul W

    2006-11-01

    The LIN-3-LET-23-mediated inductive signaling pathway plays a major role during vulval development in C. elegans. Studies on the components of this pathway have revealed positive as well as negative regulators that function to modulate the strength and specificity of the signal transduction cascade. We have carried out genetic screens to identify new regulators of this pathway by screening for suppressors of lin-3 vulvaless phenotype. The screens recovered three loci including alleles of gap-1 and a new gene represented by sli-3. Our genetic epistasis experiments suggest that sli-3 functions either downstream or in parallel to nuclear factors lin-1 and sur-2. sli-3 synergistically interacts with the previously identified negative regulators of the let-23 signaling pathway and causes excessive cell proliferation. However, in the absence of any other mutation sli-3 mutant animals display wild-type vulval induction and morphology. We propose that sli-3 functions as a negative regulator of vulval induction and defines a branch of the inductive signaling pathway. We provide evidence that sli-3 interacts with the EGF signaling pathway components during vulval induction but not during viability and ovulation processes. Thus, sli-3 helps define specificity of the EGF signaling to induce the vulva.

  10. lgl Regulates the Hippo Pathway Independently of Fat/Dachs, Kibra/Expanded/Merlin and dRASSF/dSTRIPAK

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, Linda M., E-mail: parsonsl@unimelb.edu.au [Cell Cycle and Development Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria 3002 (Australia); Department of Genetics, University of Melbourne, Melbourne, Victoria 3010 (Australia); Grzeschik, Nicola A. [Cell Cycle and Development Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria 3002 (Australia); Richardson, Helena E., E-mail: n.a.grzeschik@umcg.nl [Cell Cycle and Development Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria 3002 (Australia); Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria 3010 (Australia); Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria 3010 (Australia); Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria 3010 (Australia); Present address: Department of Cell Biology, University Medical Centre Groningen, Groningen (Netherlands)

    2014-04-16

    In both Drosophila and mammalian systems, the Hippo (Hpo) signalling pathway controls tissue growth by inhibiting cell proliferation and promoting apoptosis. The core pathway consists of a protein kinase Hpo (MST1/2 in mammals) that is regulated by a number of upstream inputs including Drosophila Ras Association Factor, dRASSF. We have previously shown in the developing Drosophila eye epithelium that loss of the apico-basal cell polarity regulator lethal-(2)-giant-larvae (lgl), and the concomitant increase in aPKC activity, results in ectopic proliferation and suppression of developmental cell death by blocking Hpo pathway signalling. Here, we further explore how Lgl/aPKC interacts with the Hpo pathway. Deregulation of the Hpo pathway by Lgl depletion is associated with the mislocalization of Hpo and dRASSF. We demonstrate that Lgl/aPKC regulate the Hpo pathway independently of upstream inputs from Fat/Dachs and the Kibra/Expanded/Merlin complex. We show depletion of Lgl also results in accumulation and mislocalization of components of the dSTRIPAK complex, a major phosphatase complex that directly binds to dRASSF and represses Hpo activity. However, depleting dSTRIPAK components, or removal of dRASSF did not rescue the lgl{sup −/−} or aPKC overexpression phenotypes. Thus, Lgl/aPKC regulate Hpo activity by a novel mechanism, independently of dRASSF and dSTRIPAK. Surprisingly, removal of dRASSF in tissue with increased aPKC activity results in mild tissue overgrowth, indicating that in this context dRASSF acts as a tumor suppressor. This effect was independent of the Hpo and Ras Mitogen Activated Protein Kinase (MAPK) pathways, suggesting that dRASSF regulates a novel pathway to control tissue growth.

  11. Nontypeable Haemophilus influenzae-Induced MyD88 Short Expression Is Regulated by Positive IKKβ and CREB Pathways and Negative ERK1/2 Pathway

    Science.gov (United States)

    Andrews, Carla S.; Miyata, Masanori; Susuki-Miyata, Seiko; Lee, Byung-Cheol; Komatsu, Kensei; Li, Jian-Dong

    2015-01-01

    Airway diseases such as asthma and chronic obstructive pulmonary disease (COPD) are characterized by excessive inflammation and are exacerbated by nontypeable Haemophilus influenzae (NTHi). Airway epithelial cells mount the initial innate immune responses to invading pathogens and thus modulate inflammation. While inflammation is necessary to eliminate a pathogen, excessive inflammation can cause damage to the host tissue. Therefore, the inflammatory response must be tightly regulated and deciphering the signaling pathways involved in this response will enhance our understanding of the regulation of the host inflammatory response. NTHi binds to TLR2 and signal propagation requires the adaptor molecule myeloid differentiation factor 88 (MyD88). An alternative spliced form of MyD88 is called MyD88 short (MyD88s) and has been identified in macrophages and embryonic cell lines as a negative regulator of inflammation. However, the role of MyD88s in NTHi-induced inflammation in airway epithelial cells remains unknown. Here we show that NTHi induces MyD88s expression and MyD88s is a negative regulator of inflammation in airway epithelial cells. We further demonstrate that MyD88s is positively regulated by IKKβ and CREB and negatively regulated by ERK1/2 signaling pathways. Taken together these data indicate that airway inflammation is controlled in a negative feedback manner involving MyD88s and suggest that airway epithelial cells are essential to maintain immune homeostasis. PMID:26669856

  12. Nontypeable Haemophilus influenzae-Induced MyD88 Short Expression Is Regulated by Positive IKKβ and CREB Pathways and Negative ERK1/2 Pathway.

    Directory of Open Access Journals (Sweden)

    Carla S Andrews

    Full Text Available Airway diseases such as asthma and chronic obstructive pulmonary disease (COPD are characterized by excessive inflammation and are exacerbated by nontypeable Haemophilus influenzae (NTHi. Airway epithelial cells mount the initial innate immune responses to invading pathogens and thus modulate inflammation. While inflammation is necessary to eliminate a pathogen, excessive inflammation can cause damage to the host tissue. Therefore, the inflammatory response must be tightly regulated and deciphering the signaling pathways involved in this response will enhance our understanding of the regulation of the host inflammatory response. NTHi binds to TLR2 and signal propagation requires the adaptor molecule myeloid differentiation factor 88 (MyD88. An alternative spliced form of MyD88 is called MyD88 short (MyD88s and has been identified in macrophages and embryonic cell lines as a negative regulator of inflammation. However, the role of MyD88s in NTHi-induced inflammation in airway epithelial cells remains unknown. Here we show that NTHi induces MyD88s expression and MyD88s is a negative regulator of inflammation in airway epithelial cells. We further demonstrate that MyD88s is positively regulated by IKKβ and CREB and negatively regulated by ERK1/2 signaling pathways. Taken together these data indicate that airway inflammation is controlled in a negative feedback manner involving MyD88s and suggest that airway epithelial cells are essential to maintain immune homeostasis.

  13. Genome Engineering of the 2,3-Butanediol Biosynthetic Pathway for Tight Regulation in Cyanobacteria.

    Science.gov (United States)

    Nozzi, Nicole E; Atsumi, Shota

    2015-11-20

    Cyanobacteria have gained popularity among the metabolic engineering community as a tractable photosynthetic host for renewable chemical production. However, though a number of successfully engineered production systems have been reported, long-term genetic stability remains an issue for cyanobacterial systems. The genetic engineering toolbox for cyanobacteria is largely lacking inducible systems for expression control. The characterization of tight regulation systems for use in cyanobacteria may help to alleviate this problem. In this work we explore the function of the IPTG inducible promoter P(L)lacO1 in the model cyanobacterium Synechococcus elongatus PCC 7942 as well as the effect of gene order within an operon on pathway expression. According to our experiments, P(L)lacO1 functions well as an inducible promoter in S. elongatus. Additionally, we found that gene order within an operon can strongly influence control of expression of each gene.

  14. S-nitrosothiols regulate nitric oxide production and storage in plants through the nitrogen assimilation pathway.

    Science.gov (United States)

    Frungillo, Lucas; Skelly, Michael J; Loake, Gary J; Spoel, Steven H; Salgado, Ione

    2014-11-11

    Nitrogen assimilation plays a vital role in plant metabolism. Assimilation of nitrate, the primary source of nitrogen in soil, is linked to the generation of the redox signal nitric oxide (NO). An important mechanism by which NO regulates plant development and stress responses is through S-nitrosylation, that is, covalent attachment of NO to cysteine residues to form S-nitrosothiols (SNO). Despite the importance of nitrogen assimilation and NO signalling, it remains largely unknown how these pathways are interconnected. Here we show that SNO signalling suppresses both nitrate uptake and reduction by transporters and reductases, respectively, to fine tune nitrate homeostasis. Moreover, NO derived from nitrate assimilation suppresses the redox enzyme S-nitrosoglutathione Reductase 1 (GSNOR1) by S-nitrosylation, preventing scavenging of S-nitrosoglutathione, a major cellular bio-reservoir of NO. Hence, our data demonstrates that (S)NO controls its own generation and scavenging by modulating nitrate assimilation and GSNOR1 activity.

  15. Current advances in DNA repair: regulation of enzymes and pathways involved in maintaining genomic stability.

    Science.gov (United States)

    Neher, Tracy M; Turchi, John J

    2011-06-15

    Novel discoveries in the DNA repair field have lead to continuous and rapid advancement of our understanding of not only DNA repair but also DNA replication and recombination. Research in the field transcends numerous areas of biology, biochemistry, physiology, and medicine, making significant connections across these broad areas of study. From early studies conducted in bacterial systems to current analyses in eukaryotic systems and human disease, the innovative research into the mechanisms of repair machines and the consequences of ineffective DNA repair has impacted a wide scientific community. This Forum contains a select mix of primary research articles in addition to a number of timely reviews covering a subset of DNA repair pathways where recent advances and novel discoveries are improving our understanding of DNA repair, its regulation, and implications to human disease.

  16. β-Spectrin regulates the hippo signaling pathway and modulates the basal actin network.

    Science.gov (United States)

    Wong, Kenneth Kin Lam; Li, Wenyang; An, Yanru; Duan, Yangyang; Li, Zhuoheng; Kang, Yibin; Yan, Yan

    2015-03-01

    Emerging evidence suggests functional regulation of the Hippo pathway by the actin cytoskeleton, although the detailed molecular mechanism remains incomplete. In a genetic screen, we identified a requirement for β-Spectrin in the posterior follicle cells for the oocyte repolarization process during Drosophila mid-oogenesis. β-spectrin mutations lead to loss of Hippo signaling activity in the follicle cells. A similar reduction of Hippo signaling activity was observed after β-Spectrin knockdown in mammalian cells. We further demonstrated that β-spectrin mutations disrupt the basal actin network in follicle cells. The abnormal stress fiber-like actin structure on the basal side of follicle cells provides a likely link between the β-spectrin mutations and the loss of the Hippo signaling activity phenotype.

  17. Neurotrophins regulate bone marrow stromal cell IL-6 expression through the MAPK pathway.

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    Fariba Rezaee

    Full Text Available BACKGROUND: The host's response to infection is characterized by altered levels of neurotrophins and an influx of inflammatory cells to sites of injured tissue. Progenitor cells that give rise to the differentiated cellular mediators of inflammation are derived from bone marrow progenitor cells where their development is regulated, in part, by cues from bone marrow stromal cells (BMSC. As such, alteration of BMSC function in response to elevated systemic mediators has the potential to alter their function in biologically relevant ways, including downstream alteration of cytokine production that influences hematopoietic development. METHODOLOGY/PRINCIPAL FINDINGS: In the current study we investigated BMSC neurotrophin receptor expression by flow cytometric analysis to determine differences in expression as well as potential to respond to NGF or BDNF. Intracellular signaling subsequent to neurotrophin stimulation of BMSC was analyzed by western blot, microarray analysis, confocal microscopy and real-time PCR. Analysis of BMSC Interleukin-6 (IL-6 expression was completed using ELISA and real-time PCR. CONCLUSION: BMSC established from different individuals had distinct expression profiles of the neurotrophin receptors, TrkA, TrkB, TrkC, and p75(NTR. These receptors were functional, demonstrated by an increase in Akt-phosphorylation following BMSC exposure to recombinant NGF or BDNF. Neurotrophin stimulation of BMSC resulted in increased IL-6 gene and protein expression which required activation of ERK and p38 MAPK signaling, but was not mediated by the NFkappaB pathway. BMSC response to neurotrophins, including the up-regulation of IL-6, may alter their support of hematopoiesis and regulate the availability of inflammatory cells for migration to sites of injury or infection. As such, these studies are relevant to the growing appreciation of the interplay between neurotropic mediators and the regulation of hematopoiesis.

  18. Bmi1 regulates mitochondrial function and the DNA damage response pathway.

    Science.gov (United States)

    Liu, Jie; Cao, Liu; Chen, Jichun; Song, Shiwei; Lee, In Hye; Quijano, Celia; Liu, Hongjun; Keyvanfar, Keyvan; Chen, Haoqian; Cao, Long-Yue; Ahn, Bong-Hyun; Kumar, Neil G; Rovira, Ilsa I; Xu, Xiao-Ling; van Lohuizen, Maarten; Motoyama, Noboru; Deng, Chu-Xia; Finkel, Toren

    2009-05-21

    Mice deficient in the Polycomb repressor Bmi1 develop numerous abnormalities including a severe defect in stem cell self-renewal, alterations in thymocyte maturation and a shortened lifespan. Previous work has implicated de-repression of the Ink4a/Arf (also known as Cdkn2a) locus as mediating many of the aspects of the Bmi1(-/-) phenotype. Here we demonstrate that cells derived from Bmi1(-/-) mice also have impaired mitochondrial function, a marked increase in the intracellular levels of reactive oxygen species and subsequent engagement of the DNA damage response pathway. Furthermore, many of the deficiencies normally observed in Bmi1(-/-) mice improve after either pharmacological treatment with the antioxidant N-acetylcysteine or genetic disruption of the DNA damage response pathway by Chk2 (also known as Chek2) deletion. These results demonstrate that Bmi1 has an unexpected role in maintaining mitochondrial function and redox homeostasis and indicate that the Polycomb family of proteins can coordinately regulate cellular metabolism with stem and progenitor cell function.

  19. Differential Maturation of the Two Regulated Secretory Pathways in Human iPSC-Derived Neurons.

    Science.gov (United States)

    Emperador Melero, Javier; Nadadhur, Aishwarya G; Schut, Desiree; Weering, Jan V; Heine, Vivi M; Toonen, Ruud F; Verhage, Matthijs

    2017-03-14

    Neurons communicate by regulated secretion of chemical signals from synaptic vesicles (SVs) and dense-core vesicles (DCVs). Here, we investigated the maturation of these two secretory pathways in micro-networks of human iPSC-derived neurons. These micro-networks abundantly expressed endogenous SV and DCV markers, including neuropeptides. DCV transport was microtubule dependent, preferentially anterograde in axons, and 2-fold faster in axons than in dendrites. SV and DCV secretion were strictly Ca(2+) and SNARE dependent. DCV secretion capacity matured until day in vitro (DIV) 36, with intense stimulation releasing 6% of the total DCV pool, and then plateaued. This efficiency is comparable with mature mouse neurons. In contrast, SV secretion capacity continued to increase until DIV50, with substantial further increase in secretion efficiency and decrease in silent synapses. These data show that the two secretory pathways can be studied in human neurons and that they mature differentially, with DCV secretion reaching maximum efficiency when that of SVs is still low.

  20. Differential Maturation of the Two Regulated Secretory Pathways in Human iPSC-Derived Neurons

    Directory of Open Access Journals (Sweden)

    Javier Emperador Melero

    2017-03-01

    Full Text Available Neurons communicate by regulated secretion of chemical signals from synaptic vesicles (SVs and dense-core vesicles (DCVs. Here, we investigated the maturation of these two secretory pathways in micro-networks of human iPSC-derived neurons. These micro-networks abundantly expressed endogenous SV and DCV markers, including neuropeptides. DCV transport was microtubule dependent, preferentially anterograde in axons, and 2-fold faster in axons than in dendrites. SV and DCV secretion were strictly Ca2+ and SNARE dependent. DCV secretion capacity matured until day in vitro (DIV 36, with intense stimulation releasing 6% of the total DCV pool, and then plateaued. This efficiency is comparable with mature mouse neurons. In contrast, SV secretion capacity continued to increase until DIV50, with substantial further increase in secretion efficiency and decrease in silent synapses. These data show that the two secretory pathways can be studied in human neurons and that they mature differentially, with DCV secretion reaching maximum efficiency when that of SVs is still low.

  1. Genetic analysis of pathway regulation for enhancing branched-chain amino acid biosynthesis in plants

    KAUST Repository

    Chen, Hao

    2010-08-01

    The branched-chain amino acids (BCAAs) valine, leucine and isoleucine are essential amino acids that play critical roles in animal growth and development. Animals cannot synthesize these amino acids and must obtain them from their diet. Plants are the ultimate source of these essential nutrients, and they synthesize BCAAs through a conserved pathway that is inhibited by its end products. This feedback inhibition has prevented scientists from engineering plants that accumulate high levels of BCAAs by simply over-expressing the respective biosynthetic genes. To identify components critical for this feedback regulation, we performed a genetic screen for Arabidopsis mutants that exhibit enhanced resistance to BCAAs. Multiple dominant allelic mutations in the VALINE-TOLERANT 1 (VAT1) gene were identified that conferred plant resistance to valine inhibition. Map-based cloning revealed that VAT1 encodes a regulatory subunit of acetohydroxy acid synthase (AHAS), the first committed enzyme in the BCAA biosynthesis pathway. The VAT1 gene is highly expressed in young, rapidly growing tissues. When reconstituted with the catalytic subunit in vitro, the vat1 mutant-containing AHAS holoenzyme exhibits increased resistance to valine. Importantly, transgenic plants expressing the mutated vat1 gene exhibit valine tolerance and accumulate higher levels of BCAAs. Our studies not only uncovered regulatory characteristics of plant AHAS, but also identified a method to enhance BCAA accumulation in crop plants that will significantly enhance the nutritional value of food and feed. © 2010 Blackwell Publishing Ltd.

  2. miR-58 family and TGF-β pathways regulate each other in Caenorhabditis elegans.

    Science.gov (United States)

    de Lucas, María Pilar; Sáez, Alberto G; Lozano, Encarnación

    2015-11-16

    Despite the fact that microRNAs (miRNAs) modulate the expression of around 60% of protein-coding genes, it is often hard to elucidate their precise role and target genes. Studying miRNA families as opposed to single miRNAs alone increases our chances of observing not only mutant phenotypes but also changes in the expression of target genes. Here we ask whether the TGF-β signalling pathways, which control many animal processes, might be modulated by miRNAs in Caenorhabditis elegans. Using a mutant for four members of the mir-58 family, we show that both TGF-β Sma/Mab (controlling body size) and TGF-β Dauer (regulating dauer, a stress-resistant larval stage) are upregulated. Thus, mir-58 family directly inhibits the expression of dbl-1 (ligand), daf-1, daf-4 and sma-6 (receptors) of TGF-β pathways. Epistasis experiments reveal that whereas the small body phenotype of the mir-58 family mutant must invoke unknown targets independent from TGF-β Sma/Mab, its dauer defectiveness can be rescued by DAF-1 depletion. Additionally, we found a negative feedback loop between TGF-β Sma/Mab and mir-58 and the related mir-80. Our results suggest that the interaction between mir-58 family and TGF-β genes is key on decisions about animal growth and stress resistance in C. elegans and perhaps other organisms.

  3. Engineering of the glycerol decomposition pathway and cofactor regulation in an industrial yeast improves ethanol production.

    Science.gov (United States)

    Zhang, Liang; Tang, Yan; Guo, Zhongpeng; Shi, Guiyang

    2013-10-01

    Glycerol is a major by-product of industrial ethanol production and its formation consumes up to 4 % of the sugar substrate. This study modified the glycerol decomposition pathway of an industrial strain of Saccharomyces cerevisiae to optimize the consumption of substrate and yield of ethanol. This study is the first to couple glycerol degradation with ethanol formation, to the best of our knowledge. The recombinant strain overexpressing GCY1 and DAK1, encoding glycerol dehydrogenase and dihydroxyacetone kinase, respectively, in glycerol degradation pathway, exhibited a moderate increase in ethanol yield (2.9 %) and decrease in glycerol yield (24.9 %) compared to the wild type with the initial glucose concentration of 15 % under anaerobic conditions. However, when the mhpF gene, encoding acetylating NAD⁺-dependent acetaldehyde dehydrogenase from Escherichia coli, was co-expressed in the aforementioned recombinant strain, a further increase in ethanol yield by 5.5 % and decrease in glycerol yield by 48 % were observed for the resultant recombinant strain GDMS1 when acetic acid was added into the medium prior to inoculation compared to the wild type. The process outlined in this study which enhances glycerol consumption and cofactor regulation in an industrial yeast is a promising metabolic engineering strategy to increase ethanol production by reducing the formation of glycerol.

  4. The Akt1/IL-6/STAT3 pathway regulates growth of lung tumor initiating cells.

    Science.gov (United States)

    Malanga, Donatella; De Marco, Carmela; Guerriero, Ilaria; Colelli, Fabiana; Rinaldo, Nicola; Scrima, Marianna; Mirante, Teresa; De Vitis, Claudia; Zoppoli, Pietro; Ceccarelli, Michele; Riccardi, Miriam; Ravo, Maria; Weisz, Alessandro; Federico, Antonella; Franco, Renato; Rocco, Gaetano; Mancini, Rita; Rizzuto, Antonia; Gulletta, Elio; Ciliberto, Gennaro; Viglietto, Giuseppe

    2015-12-15

    Here we report that the PI3K/Akt1/IL-6/STAT3 signalling pathway regulates generation and stem cell-like properties of Non-Small Cell Lung Cancer (NSCLC) tumor initiating cells (TICs). Mutant Akt1, mutant PIK3CA or PTEN loss enhances formation of lung cancer spheroids (LCS), self-renewal, expression of stemness markers and tumorigenic potential of human immortalized bronchial cells (BEAS-2B) whereas Akt inhibition suppresses these activities in established (NCI-H460) and primary NSCLC cells. Matched microarray analysis of Akt1-interfered cells and LCSs identified IL-6 as a critical target of Akt signalling in NSCLC TICs. Accordingly, suppression of Akt in NSCLC cells decreases IL-6 levels, phosphorylation of IkK and IkB, NF-kB transcriptional activity, phosphorylation and transcriptional activity of STAT3 whereas active Akt1 up-regulates them. Exposure of LCSs isolated from NSCLC cells to blocking anti-IL-6 mAbs, shRNA to IL-6 receptor or to STAT3 markedly reduces the capability to generate LCSs, to self-renew and to form tumors, whereas administration of IL-6 to Akt-interfered cells restores the capability to generate LCSs. Finally, immunohistochemical studies in NSCLC patients demonstrated a positive correlative trend between activated Akt, IL-6 expression and STAT3 phosphorylation (n = 94; p < 0.05). In conclusion, our data indicate that aberrant Akt signalling contributes to maintaining stemness in lung cancer TICs through a NF-kB/IL-6/STAT3 pathway and provide novel potential therapeutic targets for eliminating these malignant cells in NSCLC.

  5. The Akt1/IL-6/STAT3 pathway regulates growth of lung tumor initiating cells

    Science.gov (United States)

    Malanga, Donatella; De Marco, Carmela; Guerriero, Ilaria; Colelli, Fabiana; Rinaldo, Nicola; Scrima, Marianna; Mirante, Teresa; De Vitis, Claudia; Zoppoli, Pietro; Ceccarelli, Michele; Riccardi, Miriam; Ravo, Maria; Weisz, Alessandro; Federico, Antonella; Franco, Renato; Rocco, Gaetano; Mancini, Rita; Rizzuto, Antonia; Gulletta, Elio; Ciliberto, Gennaro; Viglietto, Giuseppe

    2015-01-01

    Here we report that the PI3K/Akt1/IL-6/STAT3 signalling pathway regulates generation and stem cell-like properties of Non-Small Cell Lung Cancer (NSCLC) tumor initiating cells (TICs). Mutant Akt1, mutant PIK3CA or PTEN loss enhances formation of lung cancer spheroids (LCS), self-renewal, expression of stemness markers and tumorigenic potential of human immortalized bronchial cells (BEAS-2B) whereas Akt inhibition suppresses these activities in established (NCI-H460) and primary NSCLC cells. Matched microarray analysis of Akt1-interfered cells and LCSs identified IL-6 as a critical target of Akt signalling in NSCLC TICs. Accordingly, suppression of Akt in NSCLC cells decreases IL-6 levels, phosphorylation of IkK and IkB, NF-kB transcriptional activity, phosphorylation and transcriptional activity of STAT3 whereas active Akt1 up-regulates them. Exposure of LCSs isolated from NSCLC cells to blocking anti-IL-6 mAbs, shRNA to IL-6 receptor or to STAT3 markedly reduces the capability to generate LCSs, to self-renew and to form tumors, whereas administration of IL-6 to Akt-interfered cells restores the capability to generate LCSs. Finally, immunohistochemical studies in NSCLC patients demonstrated a positive correlative trend between activated Akt, IL-6 expression and STAT3 phosphorylation (n = 94; p < 0.05). In conclusion, our data indicate that aberrant Akt signalling contributes to maintaining stemness in lung cancer TICs through a NF-kB/IL-6/STAT3 pathway and provide novel potential therapeutic targets for eliminating these malignant cells in NSCLC. PMID:26486080

  6. Unfolded protein response and activated degradative pathways regulation in GNE myopathy.

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    Honghao Li

    Full Text Available Although intracellular beta amyloid (Aβ accumulation is known as an early upstream event in the degenerative course of UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE myopathy, the process by which Aβdeposits initiate various degradative pathways, and their relationship have not been fully clarified. We studied the possible secondary responses after amyloid beta precursor protein (AβPP deposition including unfolded protein response (UPR, ubiquitin proteasome system (UPS activation and its correlation with autophagy system. Eight GNE myopathy patients and five individuals with normal muscle morphology were included in this study. We performed immunofluorescence and immunoblotting to investigate the expression of AβPP, phosphorylated tau (p-tau and endoplasmic reticulum molecular chaperones. Proteasome activities were measured by cleavage of fluorogenic substrates. The expression of proteasome subunits and linkers between proteasomal and autophagy systems were also evaluated by immunoblotting and relative quantitative real-time RT-PCR. Four molecular chaperones, glucose-regulated protein 94 (GRP94, glucose-regulated protein 78 (GRP78, calreticulin and calnexin and valosin containing protein (VCP were highly expressed in GNE myopathy. 20S proteasome subunits, three main proteasome proteolytic activities, and the factors linking UPS and autophagy system were also increased. Our study suggests that AβPP deposition results in endoplasmic reticulum stress (ERS and highly expressed VCP deliver unfolded proteins from endoplasmic reticulum to proteosomal system which is activated in endoplasmic reticulum associated degradation (ERAD in GNE myopathy. Excessive ubiquitinated unfolded proteins are exported by proteins that connect UPS and autophagy to autophagy system, which is activated as an alternative pathway for degradation.

  7. Berberine regulates AMP-activated protein kinase signaling pathways and inhibits colon tumorigenesis in mice.

    Science.gov (United States)

    Li, Weidong; Hua, Baojin; Saud, Shakir M; Lin, Hongsheng; Hou, Wei; Matter, Matthias S; Jia, Libin; Colburn, Nancy H; Young, Matthew R

    2015-10-01

    Colorectal cancer, a leading cause of cancer death, has been linked to inflammation and obesity. Berberine, an isoquinoline alkaloid, possesses anti-inflammatory, anti-diabetes and anti-tumor properties. In the azoxymethane initiated and dextran sulfate sodium (AOM/DSS) promoted colorectal carcinogenesis mouse model, berberine treated mice showed a 60% reduction in tumor number (P = 0.009), a 48% reduction in tumors 4 mm (P = 0.02) compared to vehicle treated mice. Berberine also decreased AOM/DSS induced Ki-67 and COX-2 expression. In vitro analysis showed that in addition to its anti-proliferation activity, berberine also induced apoptosis in colorectal cancer cell lines. Berberine activated AMP-activated protein kinase (AMPK), a major regulator of metabolic pathways, and inhibited mammalian target of rapamycin (mTOR), a downstream target of AMPK. Furthermore, 4E-binding protein-1 and p70 ribosomal S6 kinases, downstream targets of mTOR, were down regulated by berberine treatment. Berberine did not affect Liver kinase B1 (LKB1) activity or the mitogen-activated protein kinase pathway. Berberine inhibited Nuclear Factor kappa-B (NF-κB) activity, reduced the expression of cyclin D1 and survivin, induced phosphorylation of p53 and increased caspase-3 cleavage in vitro. Berberine inhibition of mTOR activity and p53 phosphorylation was found to be AMPK dependent, while inhibition NF-κB was AMPK independent. In vivo, berberine also activated AMPK, inhibited mTOR and p65 phosphorylation and activated caspase-3 cleavage. Our data suggests that berberine suppresses colon epithelial proliferation and tumorigenesis via AMPK dependent inhibition of mTOR activity and AMPK independent inhibition of NF-κB.

  8. Differential regulation of the Hippo pathway by adherens junctions and apical-basal cell polarity modules.

    Science.gov (United States)

    Yang, Chih-Chao; Graves, Hillary K; Moya, Ivan M; Tao, Chunyao; Hamaratoglu, Fisun; Gladden, Andrew B; Halder, Georg

    2015-02-10

    Adherens junctions (AJs) and cell polarity complexes are key players in the establishment and maintenance of apical-basal cell polarity. Loss of AJs or basolateral polarity components promotes tumor formation and metastasis. Recent studies in vertebrate models show that loss of AJs or loss of the basolateral component Scribble (Scrib) cause deregulation of the Hippo tumor suppressor pathway and hyperactivation of its downstream effectors Yes-associated protein (YAP) and Transcriptional coactivator with PDZ-binding motif (TAZ). However, whether AJs and Scrib act through the same or independent mechanisms to regulate Hippo pathway activity is not known. Here, we dissect how disruption of AJs or loss of basolateral components affect the activity of the Drosophila YAP homolog Yorkie (Yki) during imaginal disc development. Surprisingly, disruption of AJs and loss of basolateral proteins produced very different effects on Yki activity. Yki activity was cell-autonomously decreased but non-cell-autonomously elevated in tissues where the AJ components E-cadherin (E-cad) or α-catenin (α-cat) were knocked down. In contrast, scrib knockdown caused a predominantly cell-autonomous activation of Yki. Moreover, disruption of AJs or basolateral proteins had different effects on cell polarity and tissue size. Simultaneous knockdown of α-cat and scrib induced both cell-autonomous and non-cell-autonomous Yki activity. In mammalian cells, knockdown of E-cad or α-cat caused nuclear accumulation and activation of YAP without overt effects on Scrib localization and vice versa. Therefore, our results indicate the existence of multiple, genetically separable inputs from AJs and cell polarity complexes into Yki/YAP regulation.

  9. The DC-HIL/syndecan-4 pathway regulates autoimmune responses through myeloid-derived suppressor cells.

    Science.gov (United States)

    Chung, Jin-Sung; Tamura, Kyoichi; Akiyoshi, Hideo; Cruz, Ponciano D; Ariizumi, Kiyoshi

    2014-03-15

    Having discovered that the dendritic cell (DC)-associated heparan sulfate proteoglycan-dependent integrin ligand (DC-HIL) receptor on APCs inhibits T cell activation by binding to syndecan-4 (SD-4) on T cells, we hypothesized that the DC-HIL/SD-4 pathway may regulate autoimmune responses. Using experimental autoimmune encephalomyelitis (EAE) as a disease model, we noted an increase in SD-4(+) T cells in lymphoid organs of wild-type (WT) mice immunized for EAE. The autoimmune disease was also more severely induced (clinically, histologically, and immunophenotypically) in mice knocked out for SD-4 compared with WT cohorts. Moreover, infusion of SD-4(-/-) naive T cells during EAE induction into Rag2(-/-) mice also led to increased severity of EAE in these animals. Similar to SD-4 on T cells, DC-HIL expression was upregulated on myeloid cells during EAE induction, with CD11b(+)Gr-1(+) myeloid-derived suppressor cells (MDSCs) as the most expanded population and most potent T cell suppressor among the myeloid cells examined. The critical role of DC-HIL was supported by DC-HIL gene deletion or anti-DC-HIL treatment, which abrogated T cell suppressor activity of MDSCs, and also by DC-HIL activation inducing MDSC expression of IFN-γ, NO, and reactive oxygen species. Akin to SD-4(-/-) mice, DC-HIL(-/-) mice manifested exacerbated EAE. Adoptive transfer of MDSCs from EAE-affected WT mice into DC-HIL(-/-) mice reduced EAE severity to the level of EAE-immunized WT mice, an outcome that was precluded by depleting DC-HIL(+) cells from the infused MDSC preparation. Our findings indicate that the DC-HIL/SD-4 pathway regulates autoimmune responses by mediating the T cell suppressor function of MDSCs.

  10. HTLV Tax: a fascinating multifunctional co-regulator of viral and cellular pathways

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    Robert eCurrer

    2012-11-01

    Full Text Available Human T cell lymphotropic virus type 1 (HTLV-1 has been identified as the causative agent of adult T cell leukemia (ATL and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP. The virus infects between 15 and 20 million people worldwide of which approximately 2 to 5% develop ATL. The past 35 years of research have yielded significant insight into the pathogenesis of HTLV-1, including the molecular characterization of Tax, the viral transactivator and oncoprotein. In spite of these efforts, the mechanisms of oncogenesis of this pleiotropic protein remain to be fully elucidated. In this review, we illustrate the multiple oncogenic roles of Tax by summarizing a recent body of literature that refines our understanding of cellular transformation. A focused range of topics are discussed in this review including Tax-mediated regulation of the viral promoter and other cellular pathways, particularly the connection of the NF-κB pathway to both post-translational modifications of Tax and sub-cellular localization. Specifically, recent research on polyubiquitination of Tax as it relates to the activation of the IkappaB kinase (IKK complex is highlighted. Regulation of the cell cycle and DNA damage responses due to Tax are also discussed, including Tax interaction with minichromosome maintenance proteins and the role of Tax in chromatin remodeling. The recent identification of HTLV-3 has amplified the importance of the characterization of emerging viral pathogens. The challenge of the molecular determination of pathogenicity and malignant disease of this virus lies in the comparison of the viral transactivators of HTLV-1, -2, and -3 in terms of transformation and immortalization. Consequently, differences between the three proteins are currently being studied to determine what factors are required for the differences in tumorogenesis.

  11. Marburgvirus Hijacks Nrf2-Dependent Pathway by Targeting Nrf2-Negative Regulator Keap1

    Directory of Open Access Journals (Sweden)

    Audrey Page

    2014-03-01

    Full Text Available Marburg virus (MARV has a high fatality rate in humans, causing hemorrhagic fever characterized by massive viral replication and dysregulated inflammation. Here, we demonstrate that VP24 of MARV binds Kelch-like ECH-associated protein 1 (Keap1, a negative regulator of nuclear transcription factor erythroid-derived 2 (Nrf2. Binding of VP24 to Keap1 Kelch domain releases Nrf2 from Keap1-mediated inhibition promoting persistent activation of a panoply of cytoprotective genes implicated in cellular responses to oxidative stress and regulation of inflammatory responses. Increased expression of Nrf2-dependent genes was demonstrated both during MARV infection and upon ectopic expression of MARV VP24. We also show that Nrf2-deficient mice can control MARV infection when compared to lethal infection in wild-type animals, indicating that Nrf2 is critical for MARV infection. We conclude that VP24-driven activation of the Nrf2-dependent pathway is likely to contribute to dysregulation of host antiviral inflammatory responses and that it ensures survival of MARV-infected cells despite these responses.

  12. Atypical PKC-iota Controls Stem Cell Expansion via Regulation of the Notch Pathway

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    In Kyoung Mah

    2015-11-01

    Full Text Available The number of stem/progenitor cells available can profoundly impact tissue homeostasis and the response to injury or disease. Here, we propose that an atypical PKC, Prkci, is a key player in regulating the switch from an expansion to a differentiation/maintenance phase via regulation of Notch, thus linking the polarity pathway with the control of stem cell self-renewal. Prkci is known to influence symmetric cell division in invertebrates; however a definitive role in mammals has not yet emerged. Using a genetic approach, we find that loss of Prkci results in a marked increase in the number of various stem/progenitor cells. The mechanism used likely involves inactivation and symmetric localization of NUMB, leading to the activation of NOTCH1 and its downstream effectors. Inhibition of atypical PKCs may be useful for boosting the production of pluripotent stem cells, multipotent stem cells, or possibly even primordial germ cells by promoting the stem cell/progenitor fate.

  13. The cytochrome P450 epoxygenase pathway regulates the hepatic inflammatory response in fatty liver disease.

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    Robert N Schuck

    Full Text Available Fatty liver disease is an emerging public health problem without effective therapies, and chronic hepatic inflammation is a key pathologic mediator in its progression. Cytochrome P450 (CYP epoxygenases metabolize arachidonic acid to biologically active epoxyeicosatrienoic acids (EETs, which have potent anti-inflammatory effects. Although promoting the effects of EETs elicits anti-inflammatory and protective effects in the cardiovascular system, the contribution of CYP-derived EETs to the regulation of fatty liver disease-associated inflammation and injury is unknown. Using the atherogenic diet model of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH, our studies demonstrated that induction of fatty liver disease significantly and preferentially suppresses hepatic CYP epoxygenase expression and activity, and both hepatic and circulating levels of EETs in mice. Furthermore, mice with targeted disruption of Ephx2 (the gene encoding soluble epoxide hydrolase exhibited restored hepatic and circulating EET levels and a significantly attenuated induction of hepatic inflammation and injury. Collectively, these data suggest that suppression of hepatic CYP-mediated EET biosynthesis is an important pathological consequence of fatty liver disease-associated inflammation, and that the CYP epoxygenase pathway is a central regulator of the hepatic inflammatory response in NAFLD/NASH. Future studies investigating the utility of therapeutic strategies that promote the effects of CYP-derived EETs in NAFLD/NASH are warranted.

  14. Prostaglandin E2 negatively regulates AMP-activated protein kinase via protein kinase A signaling pathway.

    Science.gov (United States)

    Funahashi, Koji; Cao, Xia; Yamauchi, Masako; Kozaki, Yasuko; Ishiguro, Naoki; Kambe, Fukushi

    2009-01-01

    We investigated possible involvement of prostaglandin (PG) E2 in regulation of AMP-activated protein kinase (AMPK). When osteoblastic MG63 cells were cultured in serum-deprived media, Thr-172 phosphorylation of AMPK alpha-subunit was markedly increased. Treatment of the cells with PGE2 significantly reduced the phosphorylation. Ser-79 phosphorylation of acetyl-CoA carboxylase, a direct target for AMPK, was also reduced by PGE2. On the other hand, PGE2 reciprocally increased Ser-485 phosphorylation of the alpha-subunit that could be associated with inhibition of AMPK activity. These effects of PGE2 were mimicked by PGE2 receptor EP2 and EP4 agonists and forskolin, but not by EP1 and EP3 agonists, and the effects were suppressed by an adenylate cyclase inhibitor SQ22536 and a protein kinase A inhibitor H89. Additionally, the PGE2 effects were duplicated in primary calvarial osteoblasts. Together, the present study demonstrates that PGE2 negatively regulates AMPK activity via activation of protein kinase A signaling pathway.

  15. Exosome proteomics reveals transcriptional regulator proteins with potential to mediate downstream pathways.

    Science.gov (United States)

    Ung, Timothy H; Madsen, Helen J; Hellwinkel, Justin E; Lencioni, Alex M; Graner, Michael W

    2014-11-01

    Exosomes are virus-sized, membrane-enclosed vesicles with origins in the cellular endosomal system, but are released extracellularly. As a population, these tiny vesicles carry relatively enormous amounts of information in their protein, lipid and nucleic acid content, and the vesicles can have profound impacts on recipient cells. This review employs publically-available data combined with gene ontology applications to propose a novel concept, that exosomes transport transcriptional and translational machinery that may have direct impacts on gene expression in recipient cells. Here, we examine the previously published proteomic contents of medulloblastoma-derived exosomes, focusing on transcriptional regulators; we found that there are numerous proteins that may have potential roles in transcriptional and translational regulation with putative influence on downstream, cancer-related pathways. We expanded this search to all of the proteins in the Vesiclepedia database; using gene ontology approaches, we see that these regulatory factors are implicated in many of the processes involved in cancer initiation and progression. This information suggests that some of the effects of exosomes on recipient cells may be due to the delivery of protein factors that can directly and fundamentally change the transcriptional landscape of the cells. Within a tumor environment, this has potential to tilt the advantage towards the cancer.

  16. The inherited blindness protein AIPL1 regulates the ubiquitin-like FAT10 pathway.

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    John S Bett

    Full Text Available Mutations in AIPL1 cause the inherited blindness Leber congenital amaurosis (LCA. AIPL1 has previously been shown to interact with NUB1, which facilitates the proteasomal degradation of proteins modified with the ubiquitin-like protein FAT10. Here we report that AIPL1 binds non-covalently to free FAT10 and FAT10ylated proteins and can form a ternary complex with FAT10 and NUB1. In addition, AIPL1 antagonised the NUB1-mediated degradation of the model FAT10 conjugate, FAT10-DHFR, and pathogenic mutations of AIPL1 were defective in inhibiting this degradation. While all AIPL1 mutants tested still bound FAT10-DHFR, there was a close correlation between the ability of the mutants to interact with NUB1 and their ability to prevent NUB1-mediated degradation. Interestingly, AIPL1 also co-immunoprecipitated the E1 activating enzyme for FAT10, UBA6, suggesting AIPL1 may have a role in directly regulating the FAT10 conjugation machinery. These studies are the first to implicate FAT10 in retinal cell biology and LCA pathogenesis, and reveal a new role of AIPL1 in regulating the FAT10 pathway.

  17. The Mammary Epithelial Cell Secretome and its Regulation by Signal Transduction Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Jon M.; Waters, Katrina M.; Kathmann, Loel E.; Camp, David G.; Wiley, H. S.; Smith, Richard D.; Thrall, Brian D.

    2008-02-01

    Extracellular proteins released by mammary epithelial cells are critical mediators of cell communication, proliferation and organization, yet the actual spectrum of proteins released by any given cell (the secretome) is poorly characterized. To define the set of proteins secreted by human mammary epithelial cells (HMEC), we combined analytical and computational approaches to define a secretome protein set based upon probable biological significance. Analysis of HMEC-conditioned medium by liquid chromatography-mass spectrometry resulted in identification of 889 unique proteins, of which 151 were found to be specifically enriched in the extracellular compartment when compared with a database of proteins expressed in whole HMEC lysates. Additional high mass accuracy analysis revealed 36 proteins whose extracellular abundance increased after treatment with phorbol ester (PMA), a protein kinase C agonist and general secretagogue. Many of the PMA stimulated proteins have been reported to be aberrantly expressed in human cancers and appear to be co-regulated as multigene clusters. By inhibiting PMA-mediated transactivation of the epidermal growth factor receptor (EGFR), a pathway critically required for normal HMEC function, we found that the secretion of specific matrix metalloproteases were also coordinately regulated through EGFR transactivation. This study demonstrates a tiered strategy by which extracellular proteins can be identified and progressively assigned to classes of increasing confidence and regulatory importance.

  18. Phytochrome and retrograde signalling pathways converge to antagonistically regulate a light-induced transcriptional network.

    Science.gov (United States)

    Martín, Guiomar; Leivar, Pablo; Ludevid, Dolores; Tepperman, James M; Quail, Peter H; Monte, Elena

    2016-05-06

    Plastid-to-nucleus retrograde signals emitted by dysfunctional chloroplasts impact photomorphogenic development, but the molecular link between retrograde- and photosensory-receptor signalling has remained unclear. Here, we show that the phytochrome and retrograde signalling (RS) pathways converge antagonistically to regulate the expression of the nuclear-encoded transcription factor GLK1, a key regulator of a light-induced transcriptional network central to photomorphogenesis. GLK1 gene transcription is directly repressed by PHYTOCHROME-INTERACTING FACTOR (PIF)-class bHLH transcription factors in darkness, but light-activated phytochrome reverses this activity, thereby inducing expression. Conversely, we show that retrograde signals repress this induction by a mechanism independent of PIF mediation. Collectively, our data indicate that light at moderate levels acts through the plant's nuclear-localized sensory-photoreceptor system to induce appropriate photomorphogenic development, but at excessive levels, sensed through the separate plastid-localized RS system, acts to suppress such development, thus providing a mechanism for protection against photo-oxidative damage by minimizing the tissue exposure to deleterious radiation.

  19. Osteoblastic regulation of B lymphopoiesis is mediated by Gs{alpha}-dependent signaling pathways.

    Science.gov (United States)

    Wu, Joy Y; Purton, Louise E; Rodda, Stephen J; Chen, Min; Weinstein, Lee S; McMahon, Andrew P; Scadden, David T; Kronenberg, Henry M

    2008-11-04

    Osteoblasts play an increasingly recognized role in supporting hematopoietic development and recently have been implicated in the regulation of B lymphopoiesis. Here we demonstrate that the heterotrimeric G protein alpha subunit G(s)alpha is required in cells of the osteoblast lineage for normal postnatal B lymphocyte production. Deletion of G(s)alpha early in the osteoblast lineage results in a 59% decrease in the percentage of B cell precursors in the bone marrow. Analysis of peripheral blood from mutant mice revealed a 67% decrease in the number of circulating B lymphocytes by 10 days of age. Strikingly, other mature hematopoietic lineages are not decreased significantly. Mice lacking G(s)alpha in cells of the osteoblast lineage exhibit a reduction in pro-B and pre-B cells. Furthermore, interleukin (IL)-7 expression is attenuated in G(s)alpha-deficient osteoblasts, and exogenous IL-7 is able to restore B cell precursor populations in the bone marrow of mutant mice. Finally, the defect in B lymphopoiesis can be rescued by transplantation into a WT microenvironment. These findings confirm that osteoblasts are an important component of the B lymphocyte niche and demonstrate in vivo that G(s)alpha-dependent signaling pathways in cells of the osteoblast lineage extrinsically regulate bone marrow B lymphopoiesis, at least partially in an IL-7-dependent manner.

  20. Osteoblastic regulation of B lymphopoiesis is mediated by Gsα-dependent signaling pathways

    Science.gov (United States)

    Wu, Joy Y.; Purton, Louise E.; Rodda, Stephen J.; Chen, Min; Weinstein, Lee S.; McMahon, Andrew P.; Scadden, David T.; Kronenberg, Henry M.

    2008-01-01

    Osteoblasts play an increasingly recognized role in supporting hematopoietic development and recently have been implicated in the regulation of B lymphopoiesis. Here we demonstrate that the heterotrimeric G protein α subunit Gsα is required in cells of the osteoblast lineage for normal postnatal B lymphocyte production. Deletion of Gsα early in the osteoblast lineage results in a 59% decrease in the percentage of B cell precursors in the bone marrow. Analysis of peripheral blood from mutant mice revealed a 67% decrease in the number of circulating B lymphocytes by 10 days of age. Strikingly, other mature hematopoietic lineages are not decreased significantly. Mice lacking Gsα in cells of the osteoblast lineage exhibit a reduction in pro-B and pre-B cells. Furthermore, interleukin (IL)-7 expression is attenuated in Gsα-deficient osteoblasts, and exogenous IL-7 is able to restore B cell precursor populations in the bone marrow of mutant mice. Finally, the defect in B lymphopoiesis can be rescued by transplantation into a WT microenvironment. These findings confirm that osteoblasts are an important component of the B lymphocyte niche and demonstrate in vivo that Gsα-dependent signaling pathways in cells of the osteoblast lineage extrinsically regulate bone marrow B lymphopoiesis, at least partially in an IL-7-dependent manner. PMID:18957542

  1. N-Myristoylation Regulates the SnRK1 Pathway in Arabidopsis[W

    Science.gov (United States)

    Pierre, Michèle; Traverso, José A.; Boisson, Bertrand; Domenichini, Séverine; Bouchez, David; Giglione, Carmela; Meinnel, Thierry

    2007-01-01

    Cotranslational and posttranslational modifications are increasingly recognized as important in the regulation of numerous essential cellular functions. N-myristoylation is a lipid modification ensuring the proper function and intracellular trafficking of proteins involved in many signaling pathways. Arabidopsis thaliana, like human, has two tightly regulated N-myristoyltransferase (NMT) genes, NMT1 and NMT2. Characterization of knockout mutants showed that NMT1 was strictly required for plant viability, whereas NMT2 accelerated flowering. NMT1 impairment induced extremely severe defects in the shoot apical meristem during embryonic development, causing growth arrest after germination. A transgenic plant line with an inducible NMT1 gene demonstrated that NMT1 expression had further effects at later stages. NMT2 did not compensate for NMT1 in the nmt1-1 mutant, but NMT2 overexpression resulted in shoot and root meristem abnormalities. Various data from complementation experiments in the nmt1-1 background, using either yeast or human NMTs, demonstrated a functional link between the developmental arrest of nmt1-1 mutants and the myristoylation state of an extremely small set of protein targets. We show here that protein N-myristoylation is systematically associated with shoot meristem development and that SnRK1 (for SNF1-related kinase) is one of its essential primary targets. PMID:17827350

  2. Recent developments on lipolysis regulation in humans and discovery of a new lipolytic pathway.

    Science.gov (United States)

    Lafontan, M; Sengenes, C; Galitzky, J; Berlan, M; De Glisezinski, I; Crampes, F; Stich, V; Langin, D; Barbe, P; Rivière, D

    2000-11-01

    In man, the major hormones controlling the lipolytic function are insulin (inhibition of lipolysis) and catecholamines (stimulation of lipolysis). Catecholamines are of major importance for the regulation of lipid mobilization in human adipose tissue and for the increase of non-esterified fatty acid supply to the working muscle. In vitro studies have shown that there are differences in the catecholaminergic control of fat cells from various fat deposits and a number of physiological and pathological alterations of catecholamine-induced lipolysis have been reported. Lipolytic resistance to catecholamines has been reported in subcutaneous adipose tissue, the major fat depot in obese subjects. Multiple alterations in catecholamine signal transduction pathways have been reported. In situ microdialysis allows a physiological exploration of adipose tissue biology. Recent data obtained on the catecholaminergic regulation of lipolysis and lipid mobilization, using microdialysis in humans, will be analysed. A potent lipolytic and lipomobilizing effect of atrial natriuretic peptide has recently been discovered; the mechanisms of action and physiological relevance will also be discussed.

  3. Notch1 regulates hippocampal plasticity through interaction with the Reelin pathway, glutamatergic transmission and CREB signaling

    Directory of Open Access Journals (Sweden)

    Emanuele eBrai

    2015-11-01

    Full Text Available Notch signaling plays a crucial role in adult brain function such as synaptic plasticity, memory and olfaction. Several reports suggest an involvement of this pathway in neurodegenerative dementia. Yet, to date, the mechanism underlying Notch activity in mature neurons remains unresolved. In this work, we investigate how Notch regulates synaptic potentiation and contributes to the establishment of memory in mice. We observe that Notch1 is a postsynaptic receptor with functional interactions with the Reelin receptor, ApoER2, and the ionotropic receptor, NMDAR. Targeted loss of Notch1 in the hippocampal CA fields affects Reelin signaling by influencing Dab1 expression and impairs the synaptic potentiation achieved through Reelin stimulation. Further analysis indicates that loss of Notch1 affects the expression and composition of the NMDAR but not AMPAR. Glutamatergic signaling is further compromised through downregulation of CamKII and its secondary and tertiary messengers resulting in reduced CREB signaling. Our results identify Notch1 as an important regulator of mechanisms involved in synaptic plasticity and memory formation. These findings emphasize the possible involvement of this signaling receptor in dementia.

  4. Rassf5 and Ndr kinases regulate neuronal polarity through Par3 phosphorylation in a novel pathway.

    Science.gov (United States)

    Yang, Rui; Kong, Eryan; Jin, Jing; Hergovich, Alexander; Püschel, Andreas W

    2014-08-15

    The morphology and polarized growth of cells depend on pathways that control the asymmetric distribution of regulatory factors. The evolutionarily conserved Ndr kinases play important roles in cell polarity and morphogenesis in yeast and invertebrates but it is unclear whether they perform a similar function in mammalian cells. Here, we analyze the function of mammalian Ndr1 and Ndr2 (also known as STK38 or STK38L, respectively) in the establishment of polarity in neurons. We show that they act downstream of the tumor suppressor Rassf5 and upstream of the polarity protein Par3 (also known as PARD3). Rassf5 and Ndr1 or Ndr2 are required during the polarization of hippocampal neurons to prevent the formation of supernumerary axons. Mechanistically, the Ndr kinases act by phosphorylating Par3 at Ser383 to inhibit its interaction with dynein, thereby polarizing the distribution of Par3 and reinforcing axon specification. Our results identify a novel Rassf5-Ndr-Par3 signaling cascade that regulates the transport of Par3 during the establishment of neuronal polarity. Their role in neuronal polarity suggests that Ndr kinases perform a conserved function as regulators of cell polarity.

  5. Gap Junctions in the Ventral Hippocampal-Medial Prefrontal Pathway Are Involved in Anxiety Regulation

    Science.gov (United States)

    Schoenfeld, Timothy J.; Kloth, Alexander D.; Hsueh, Brian; Runkle, Matthew B.; Kane, Gary A.; Wang, Samuel S.-H.

    2014-01-01

    Anxiety disorders are highly prevalent but little is known about their underlying mechanisms. Gap junctions exist in brain regions important for anxiety regulation, such as the ventral hippocampus (vHIP) and mPFC, but their functions in these areas have not been investigated. Using pharmacological blockade of neuronal gap junctions combined with electrophysiological recordings, we found that gap junctions play a role in theta rhythm in the vHIP and mPFC of adult mice. Bilateral infusion of neuronal gap junction blockers into the vHIP decreased anxiety-like behavior on the elevated plus maze and open field. Similar anxiolytic effects were observed with unilateral infusion of these drugs into the vHIP combined with contralateral infusion into the mPFC. No change in anxious behavior was observed with gap junction blockade in the unilateral vHIP alone or in the bilateral dorsal HIP. Since physical exercise is known to reduce anxiety, we examined the effects of long-term running on the expression of the neuronal gap junction protein connexin-36 among inhibitory interneurons and found a reduction in the vHIP. Despite this change, we observed no alteration in theta frequency or power in long-term runners. Collectively, these findings suggest that neuronal gap junctions in the vHIP–mPFC pathway are important for theta rhythm and anxiety regulation under sedentary conditions but that additional mechanisms are likely involved in running-induced reduction in anxiety. PMID:25411496

  6. Redox and trace metal regulation of ion channels in the pain pathway.

    Science.gov (United States)

    Evans, J Grayson; Todorovic, Slobodan M

    2015-09-15

    Given the clinical significance of pain disorders and the relative ineffectiveness of current therapeutics, it is important to identify alternative means of modulating nociception. The most obvious pharmacological targets are the ion channels that facilitate nervous transmission from pain sensors in the periphery to the processing regions within the brain and spinal cord. In order to design effective pharmacological tools for this purpose, however, it is first necessary to understand how these channels are regulated. A growing area of research involves the investigation of the role that trace metals and endogenous redox agents play in modulating the activity of a diverse group of ion channels within the pain pathway. In the present review, the most recent literature concerning trace metal and redox regulation of T-type calcium channels, NMDA (N-methyl-D-aspartate) receptors, GABAA (γ-aminobutyric acid A) receptors and TRP (transient receptor potential) channels are described to gain a comprehensive understanding of the current state of the field as well as to provide a basis for future thought and experimentation.

  7. Identification of metabolism pathways directly regulated by sigma54 factor in Bacillus thuringiensis

    Science.gov (United States)

    Peng, Qi; Wang, Guannan; Liu, Guiming; Zhang, Jie; Song, Fuping

    2015-01-01

    Sigma54 (σ54) regulates nitrogen and carbon utilization in bacteria. Promoters that are σ54-dependent are highly conserved and contain short sequences located at the −24 and −12 positions upstream of the transcription initiation site. σ54 requires regulatory proteins known as bacterial enhancer-binding proteins (bEBPs) to activate gene transcription. We show that σ54 regulates the capacity to grow on various nitrogen sources using a Bacillus thuringiensis HD73 mutant lacking the sigL gene encoding σ54 (ΔsigL). A 2-fold-change cutoff and a false discovery rate cutoff of P < 0.05 were used to analyze the DNA microarray data, which revealed 255 genes that were downregulated and 121 that were upregulated in the ΔsigL mutant relative to the wild-type HD73 strain. The σ54 regulon (stationary phase) was characterized by DNA microarray, bioinformatics, and functional assay; 16 operons containing 47 genes were identified whose promoter regions contain the conserved −12/−24 element and whose transcriptional activities were abolished or reduced in the ΔsigL mutant. Eight σ54-dependent transcriptional bEBPs were found in the Bt HD73 genome, and they regulated nine σ54-dependent promoters. The metabolic pathways activated by σ54 in this process have yet to be identified in Bacillus thuringiensis; nonetheless, the present analysis of the σ54 regulon provides a better understanding of the physiological roles of σ factors in bacteria. PMID:26029175

  8. Two-component signal transduction pathways regulating growth and cell cycle progression in a bacterium: a system-level analysis.

    Directory of Open Access Journals (Sweden)

    Jeffrey M Skerker

    2005-10-01

    Full Text Available Two-component signal transduction systems, comprised of histidine kinases and their response regulator substrates, are the predominant means by which bacteria sense and respond to extracellular signals. These systems allow cells to adapt to prevailing conditions by modifying cellular physiology, including initiating programs of gene expression, catalyzing reactions, or modifying protein-protein interactions. These signaling pathways have also been demonstrated to play a role in coordinating bacterial cell cycle progression and development. Here we report a system-level investigation of two-component pathways in the model organism Caulobacter crescentus. First, by a comprehensive deletion analysis we show that at least 39 of the 106 two-component genes are required for cell cycle progression, growth, or morphogenesis. These include nine genes essential for growth or viability of the organism. We then use a systematic biochemical approach, called phosphotransfer profiling, to map the connectivity of histidine kinases and response regulators. Combining these genetic and biochemical approaches, we identify a new, highly conserved essential signaling pathway from the histidine kinase CenK to the response regulator CenR, which plays a critical role in controlling cell envelope biogenesis and structure. Depletion of either cenK or cenR leads to an unusual, severe blebbing of cell envelope material, whereas constitutive activation of the pathway compromises cell envelope integrity, resulting in cell lysis and death. We propose that the CenK-CenR pathway may be a suitable target for new antibiotic development, given previous successes in targeting the bacterial cell wall. Finally, the ability of our in vitro phosphotransfer profiling method to identify signaling pathways that operate in vivo takes advantage of an observation that histidine kinases are endowed with a global kinetic preference for their cognate response regulators. We propose that this

  9. Nutrient-regulated antisense and intragenic RNAs modulate a signal transduction pathway in yeast.

    Directory of Open Access Journals (Sweden)

    Masafumi Nishizawa

    2008-12-01

    Full Text Available The budding yeast Saccharomyces cerevisiae alters its gene expression profile in response to a change in nutrient availability. The PHO system is a well-studied case in the transcriptional regulation responding to nutritional changes in which a set of genes (PHO genes is expressed to activate inorganic phosphate (Pi metabolism for adaptation to Pi starvation. Pi starvation triggers an inhibition of Pho85 kinase, leading to migration of unphosphorylated Pho4 transcriptional activator into the nucleus and enabling expression of PHO genes. When Pi is sufficient, the Pho85 kinase phosphorylates Pho4, thereby excluding it from the nucleus and resulting in repression (i.e., lack of transcription of PHO genes. The Pho85 kinase has a role in various cellular functions other than regulation of the PHO system in that Pho85 monitors whether environmental conditions are adequate for cell growth and represses inadequate (untimely responses in these cellular processes. In contrast, Pho4 appears to activate some genes involved in stress response and is required for G1 arrest caused by DNA damage. These facts suggest the antagonistic function of these two players on a more general scale when yeast cells must cope with stress conditions. To explore general involvement of Pho4 in stress response, we tried to identify Pho4-dependent genes by a genome-wide mapping of Pho4 and Rpo21 binding (Rpo21 being the largest subunit of RNA polymerase II using a yeast tiling array. In the course of this study, we found Pi- and Pho4-regulated intragenic and antisense RNAs that could modulate the Pi signal transduction pathway. Low-Pi signal is transmitted via certain inositol polyphosphate (IP species (IP7 that are synthesized by Vip1 IP6 kinase. We have shown that Pho4 activates the transcription of antisense and intragenic RNAs in the KCS1 locus to down-regulate the Kcs1 activity, another IP6 kinase, by producing truncated Kcs1 protein via hybrid formation with the KCS1 m

  10. Notch pathway regulates female germ cell meiosis progression and early oogenesis events in fetal mouse.

    Science.gov (United States)

    Feng, Yan-Min; Liang, Gui-Jin; Pan, Bo; Qin, Xun-Si; Zhang, Xi-Feng; Chen, Chun-Lei; Li, Lan; Cheng, Shun-Feng; De Felici, Massimo; Shen, Wei

    2014-01-01

    A critical process of early oogenesis is the entry of mitotic oogonia into meiosis, a cell cycle switch regulated by a complex gene regulatory network. Although Notch pathway is involved in numerous important aspects of oogenesis in invertebrate species, whether it plays roles in early oogenesis events in mammals is unknown. Therefore, the rationale of the present study was to investigate the roles of Notch signaling in crucial processes of early oogenesis, such as meiosis entry and early oocyte growth. Notch receptors and ligands were localized in mouse embryonic female gonads and 2 Notch inhibitors, namely DAPT and L-685,458, were used to attenuate its signaling in an in vitro culture system of ovarian tissues from 12.5 days post coitum (dpc) fetus. The results demonstrated that the expression of Stra8, a master gene for germ cell meiosis, and its stimulation by retinoic acid (RA) were reduced after suppression of Notch signaling, and the other meiotic genes, Dazl, Dmc1, and Rec8, were abolished or markedly decreased. Furthermore, RNAi of Notch1 also markedly inhibited the expression of Stra8 and SCP3 in cultured female germ cells. The increased methylation status of CpG islands within the Stra8 promoter of the oocytes was observed in the presence of DAPT, indicating that Notch signaling is probably necessary for maintaining the epigenetic state of this gene in a way suitable for RA stimulation. Furthermore, in the presence of Notch inhibitors, progression of oocytes through meiosis I was markedly delayed. At later culture periods, the rate of oocyte growth was decreased, which impaired subsequent primordial follicle assembly in cultured ovarian tissues. Taken together, these results suggested new roles of the Notch signaling pathway in female germ cell meiosis progression and early oogenesis events in mammals.

  11. Acute regulation of cardiac metabolism by the hexosamine biosynthesis pathway and protein O-GlcNAcylation.

    Directory of Open Access Journals (Sweden)

    Boglárka Laczy

    Full Text Available OBJECTIVE: The hexosamine biosynthesis pathway (HBP flux and protein O-linked N-acetyl-glucosamine (O-GlcNAc levels have been implicated in mediating the adverse effects of diabetes in the cardiovascular system. Activation of these pathways with glucosamine has been shown to mimic some of the diabetes-induced functional and structural changes in the heart; however, the effect on cardiac metabolism is not known. Therefore, the primary goal of this study was to determine the effects of glucosamine on cardiac substrate utilization. METHODS: Isolated rat hearts were perfused with glucosamine (0-10 mM to increase HBP flux under normoxic conditions. Metabolic fluxes were determined by (13C-NMR isotopomer analysis; UDP-GlcNAc a precursor of O-GlcNAc synthesis was assessed by HPLC and immunoblot analysis was used to determine O-GlcNAc levels, phospho- and total levels of AMPK and ACC, and membrane levels of FAT/CD36. RESULTS: Glucosamine caused a dose dependent increase in both UDP-GlcNAc and O-GlcNAc levels, which was associated with a significant increase in palmitate oxidation with a concomitant decrease in lactate and pyruvate oxidation. There was no effect of glucosamine on AMPK or ACC phosphorylation; however, membrane levels of the fatty acid transport protein FAT/CD36 were increased and preliminary studies suggest that FAT/CD36 is a potential target for O-GlcNAcylation. CONCLUSION/INTERPRETATION: These data demonstrate that acute modulation of HBP and protein O-GlcNAcylation in the heart stimulates fatty acid oxidation, possibly by increasing plasma membrane levels of FAT/CD36, raising the intriguing possibility that the HBP and O-GlcNAc turnover represent a novel, glucose dependent mechanism for regulating cardiac metabolism.

  12. Induction of mitochondrial alternative oxidase in response to a cell signal pathway down-regulating the cytochrome pathway prevents programmed cell death.

    Science.gov (United States)

    Vanlerberghe, Greg C; Robson, Christine A; Yip, Justine Y H

    2002-08-01

    Treatment of tobacco (Nicotiana tabacum L. cv Petit Havana SR1) cells with cysteine (Cys) triggers a signal pathway culminating in a large loss of mitochondrial cytochrome (cyt) pathway capacity. This down-regulation of the cyt path likely requires events outside the mitochondrion and is effectively blocked by cantharidin or endothall, indicating that protein dephosphorylation is one critical process involved. Generation of reactive oxygen species, cytosolic protein synthesis, and Ca(2+) flux from organelles also appear to be involved. Accompanying the loss of cyt path is a large induction of alternative oxidase (AOX) protein and capacity. Induction of AOX allows the cells to maintain high rates of respiration, indicating that the lesion triggered by Cys is in the cyt path downstream of ubiquinone. Consistent with this, transgenic (AS8) cells unable to induce AOX (due to the presence of an antisense transgene) lose all respiratory capacity upon Cys treatment. This initiates in AS8 a programmed cell death pathway, as evidenced by the accumulation of oligonucleosomal fragments of DNA as the culture dies. Alternatively, wild-type cells remain viable and eventually recover their cyt path. Induction of AOX in response to a chemical inhibition of the cyt path (by antimycin A) is also dependent upon protein dephosphorylation and the generation of reactive oxygen species. Common events required for both down-regulation of the cyt path and induction of AOX may represent a mechanism to coordinate the biogenesis of these two electron transport paths. Such coordinate regulation may be necessary, not only to satisfy metabolic demands, but also to modulate the initiation of a programmed cell death pathway responsive to mitochondrial respiratory status.

  13. mir-30d Regulates multiple genes in the autophagy pathway and impairs autophagy process in human cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaojun [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zhong, Xiaomin [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Tanyi, Janos L.; Shen, Jianfeng [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Xu, Congjian [Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Gao, Peng [Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zheng, Tim M. [Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); DeMichele, Angela [Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); Zhang, Lin, E-mail: linzhang@mail.med.upenn.edu [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)

    2013-02-15

    Highlights: ► Gene set enrichment analysis indicated mir-30d might regulate the autophagy pathway. ► mir-30d represses the expression of BECN1, BNIP3L, ATG12, ATG5 and ATG2. ► BECN1, BNIP3L, ATG12, ATG5 and ATG2 are direct targets of mir-30d. ► mir-30d inhibits autophagosome formation and LC3B-I conversion to LC3B-II. ► mir-30d regulates the autophagy process. -- Abstract: In human epithelial cancers, the microRNA (miRNA) mir-30d is amplified with high frequency and serves as a critical oncomir by regulating metastasis, apoptosis, proliferation, and differentiation. Autophagy, a degradation pathway for long-lived protein and organelles, regulates the survival and death of many cell types. Increasing evidence suggests that autophagy plays an important function in epithelial tumor initiation and progression. Using a combined bioinformatics approach, gene set enrichment analysis, and miRNA target prediction, we found that mir-30d might regulate multiple genes in the autophagy pathway including BECN1, BNIP3L, ATG12, ATG5, and ATG2. Our further functional experiments demonstrated that the expression of these core proteins in the autophagy pathway was directly suppressed by mir-30d in cancer cells. Finally, we showed that mir-30d regulated the autophagy process by inhibiting autophagosome formation and LC3B-I conversion to LC3B-II. Taken together, our results provide evidence that the oncomir mir-30d impairs the autophagy process by targeting multiple genes in the autophagy pathway. This result will contribute to understanding the molecular mechanism of mir-30d in tumorigenesis and developing novel cancer therapy strategy.

  14. The p53-p21-DREAM-CDE/CHR pathway regulates G2/M cell cycle genes.

    Science.gov (United States)

    Fischer, Martin; Quaas, Marianne; Steiner, Lydia; Engeland, Kurt

    2016-01-01

    The tumor suppressor p53 functions predominantly as a transcription factor by activating and downregulating gene expression, leading to cell cycle arrest or apoptosis. p53 was shown to indirectly repress transcription of the CCNB2, KIF23 and PLK4 cell cycle genes through the recently discovered p53-p21-DREAM-CDE/CHR pathway. However, it remained unclear whether this pathway is commonly used. Here, we identify genes regulated by p53 through this pathway in a genome-wide computational approach. The bioinformatic analysis is based on genome-wide DREAM complex binding data, p53-depedent mRNA expression data and a genome-wide definition of phylogenetically conserved CHR promoter elements. We find 210 target genes that are expected to be regulated by the p53-p21-DREAM-CDE/CHR pathway. The target gene list was verified by detailed analysis of p53-dependent repression of the cell cycle genes B-MYB (MYBL2), BUB1, CCNA2, CCNB1, CHEK2, MELK, POLD1, RAD18 and RAD54L. Most of the 210 target genes are essential regulators of G2 phase and mitosis. Thus, downregulation of these genes through the p53-p21-DREAM-CDE/CHR pathway appears to be a principal mechanism for G2/M cell cycle arrest by p53.

  15. Regulation of the Wnt/β-Catenin Signaling Pathway by Human Papillomavirus E6 and E7 Oncoproteins

    Directory of Open Access Journals (Sweden)

    Jesus Omar Muñoz Bello

    2015-08-01

    Full Text Available Cell signaling pathways are the mechanisms by which cells transduce external stimuli, which control the transcription of genes, to regulate diverse biological effects. In cancer, distinct signaling pathways, such as the Wnt/β-catenin pathway, have been implicated in the deregulation of critical molecular processes that affect cell proliferation and differentiation. For example, changes in β-catenin localization have been identified in Human Papillomavirus (HPV-related cancers as the lesion progresses. Specifically, β-catenin relocates from the membrane/cytoplasm to the nucleus, suggesting that this transcription regulator participates in cervical carcinogenesis. The E6 and E7 oncoproteins are responsible for the transforming activity of HPV, and some studies have implicated these viral oncoproteins in the regulation of the Wnt/β-catenin pathway. Nevertheless, new interactions of HPV oncoproteins with cellular proteins are emerging, and the study of the biological effects of such interactions will help to understand HPV-related carcinogenesis. Viruses 2015, 7 4735 This review addresses the accumulated evidence of the involvement of the HPV E6 and E7 oncoproteins in the activation of the Wnt/β-catenin pathway.

  16. The phosphoinositide 3-kinase signalling pathway in normal and malignant B cells: activation mechanisms, regulation and impact on cellular functions

    Directory of Open Access Journals (Sweden)

    Samantha D Pauls

    2012-08-01

    Full Text Available The phosphoinositide 3-kinase (PI3K pathway is a central signal transduction axis controlling normal B cell homeostasis and activation in humoral immunity. The p110δ PI3K catalytic subunit has emerged as a critical mediator of multiple B cell functions. The activity of this pathway is regulated at multiple levels, with inositol phosphatases PTEN and SHIP both playing critical roles. When deregulated, the PI3K pathway can contribute to B cell malignancies and autoantibody production. This review summarizes current knowledge on key mechanisms that activate and regulate the PI3K pathway and influence normal B cell functional responses including the development of B cell subsets, antigen presentation, immunogloblulin isotype switch, germinal center responses and maintenance of B cell anergy. We also discuss PI3K pathway alterations reported in select B cell malignancies and highlight studies indicating the functional significance of this pathway in malignant B cell survival and growth within tissue microenvironments. Finally, we comment on early clinical trial results, which support PI3K inhibition as a promising treatment of chronic lymphocytic leukemia.

  17. The phosphoinositide 3-kinase signaling pathway in normal and malignant B cells: activation mechanisms, regulation and impact on cellular functions.

    Science.gov (United States)

    Pauls, Samantha D; Lafarge, Sandrine T; Landego, Ivan; Zhang, Tingting; Marshall, Aaron J

    2012-01-01

    The phosphoinositide 3-kinase (PI3K) pathway is a central signal transduction axis controlling normal B cell homeostasis and activation in humoral immunity. The p110δ PI3K catalytic subunit has emerged as a critical mediator of multiple B cell functions. The activity of this pathway is regulated at multiple levels, with inositol phosphatases PTEN and SHIP both playing critical roles. When deregulated, the PI3K pathway can contribute to B cell malignancies and autoantibody production. This review summarizes current knowledge on key mechanisms that activate and regulate the PI3K pathway and influence normal B cell functional responses including the development of B cell subsets, antigen presentation, immunoglobulin isotype switch, germinal center responses, and maintenance of B cell anergy. We also discuss PI3K pathway alterations reported in select B cell malignancies and highlight studies indicating the functional significance of this pathway in malignant B cell survival and growth within tissue microenvironments. Finally, we comment on early clinical trial results, which support PI3K inhibition as a promising treatment of chronic lymphocytic leukemia.

  18. PKCa and PKCd regulate ADAM17-mediated ectodomain shedding of heparin binding-EGF through separate pathways

    DEFF Research Database (Denmark)

    Kveiborg, Marie; Instrell, Rachael; Rowlands, Christina;

    2011-01-01

    -EGF. We identified PKCa as the key participant in the activation of ADAM17 and suggest that it acts in parallel with a pathway linking PKCd and ERK activity. While PKCa specifically regulated PMA-induced shedding, PKCd and ERK influenced both constitutive and inducible shedding by apparently affecting...

  19. Role of cholinergic anti-inflammatory pathway in regulating host response and its interventional strategy for inflammatory diseases

    Institute of Scientific and Technical Information of China (English)

    WANG Da-wei; ZHOU Rong-bin; YAO Yong-ming

    2009-01-01

    @@ The cholinergic anti-inflammatory pathway (CAP) is a neurophysiological mechanism that regulates the immune system. The CAP inhibits inflammation by suppressing cytokine synthesis via release of acetylcholine in organs of the reticuloendothelial system, including the lungs, spleen, liver, kidneys and gastrointestinal tract.

  20. PI3K/mTOR-dependent signaling pathway as a possible regulator of processing bodies’ assembly

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    Filonenko V. V.

    2011-10-01

    Full Text Available Aim. To study the role of PI3K/mTOR signaling pathway in regulation of processing body (PB assembly. Methods. During this study we employed cell imaging technique and Western blot analysis. Results. It was shown that treatment of cells with the specific inhibitors of PI3K/mTOR pathway leads to changes of PBs’ number and size within cells as well as proteasomal degradation of their scaffold protein RCD-8. Conclusions. We speculate that mTOR/PI3K pathway may regulate in part the dynamic of PB formation in the cell by affecting the stability of RCD-8 protein and therefore controle mRNA metabolism

  1. Presenilin 1 regulates epidermal growth factor receptor turnover and signaling in the endosomal-lysosomal pathway.

    Science.gov (United States)

    Repetto, Emanuela; Yoon, Il-Sang; Zheng, Hui; Kang, David E

    2007-10-26

    Mutations in the gene encoding presenilin 1 (PS1) cause the most aggressive form of early-onset familial Alzheimer disease. In addition to its well established role in Abeta production and Notch proteolysis, PS1 has been shown to mediate other physiological activities, such as regulation of the Wnt/beta-catenin signaling pathway, modulation of phosphatidylinositol 3-kinase/Akt and MEK/ERK signaling, and trafficking of select membrane proteins and/or intracellular vesicles. In this study, we present evidence that PS1 is a critical regulator of a key signaling receptor tyrosine kinase, epidermal growth factor receptor (EGFR). Specifically, EGFR levels were robustly increased in fibroblasts deficient in both PS1 and PS2 (PS(-/-)) due to delayed turnover of EGFR protein. Stable transfection of wild-type PS1 but not PS2 corrected EGFR to levels comparable to PS(+/+) cells, while FAD PS1 mutations showed partial loss of activity. The C-terminal fragment of PS1 was sufficient to fully reduce EGFR levels. In addition, the rapid ligand-induced degradation of EGFR was markedly delayed in PS(-/-) cells, resulting in prolonged signal activation. Despite the defective turnover of EGFR, ligand-induced autophosphorylation, ubiquitination, and endocytosis of EGFR were not affected by the lack of PS1. Instead, the trafficking of EGFR from early endosomes to lysosomes was severely delayed by PS1 deficiency. Elevation of EGFR was also seen in brains of adult mice conditionally ablated in PS1 and in skin tumors associated with the loss of PS1. These findings demonstrate a critical role of PS1 in the trafficking and turnover of EGFR and suggest potential pathogenic effects of elevated EGFR as well as perturbed endosomal-lysosomal trafficking in cell cycle control and Alzheimer disease.

  2. Streptococcus pyogenes malate degradation pathway links pH regulation and virulence.

    Science.gov (United States)

    Paluscio, Elyse; Caparon, Michael G

    2015-03-01

    The ability of Streptococcus pyogenes to infect different niches within its human host most likely relies on its ability to utilize alternative carbon sources. In examining this question, we discovered that all sequenced S. pyogenes strains possess the genes for the malic enzyme (ME) pathway, which allows malate to be used as a supplemental carbon source for growth. ME is comprised of four genes in two adjacent operons, with the regulatory two-component MaeKR required for expression of genes encoding a malate permease (maeP) and malic enzyme (maeE). Analysis of transcription indicated that expression of maeP and maeE is induced by both malate and low pH, and induction in response to both cues is dependent on the MaeK sensor kinase. Furthermore, both maePE and maeKR are repressed by glucose, which occurs via a CcpA-independent mechanism. Additionally, malate utilization requires the PTS transporter EI enzyme (PtsI), as a PtsI(-) mutant fails to express the ME genes and is unable to utilize malate. Virulence of selected ME mutants was assessed in a murine model of soft tissue infection. MaeP(-), MaeK(-), and MaeR(-) mutants were attenuated for virulence, whereas a MaeE(-) mutant showed enhanced virulence compared to that of the wild type. Taken together, these data show that ME contributes to S. pyogenes' carbon source repertory, that malate utilization is a highly regulated process, and that a single regulator controls ME expression in response to diverse signals. Furthermore, malate uptake and utilization contribute to the adaptive pH response, and ME can influence the outcome of infection.

  3. Notch pathway modulation on bone marrow-derived vascular precursor cells regulates their angiogenic and wound healing potential.

    Science.gov (United States)

    Caiado, Francisco; Real, Carla; Carvalho, Tânia; Dias, Sérgio

    2008-01-01

    Bone marrow (BM) derived vascular precursor cells (BM-PC, endothelial progenitors) are involved in normal and malignant angiogenesis, in ischemia and in wound healing. However, the mechanisms by which BM-PC stimulate the pre-existing endothelial cells at sites of vascular remodelling/recovery, and their contribution towards the formation of new blood vessels are still undisclosed. In the present report, we exploited the possibility that members of the Notch signalling pathway, expressed by BM-PC during endothelial differentiation, might regulate their pro-angiogenic or pro-wound healing properties. We demonstrate that Notch pathway modulates the adhesion of BM-PC to extracellular matrix (ECM) in vitro via regulation of integrin alpha3beta1; and that Notch pathway inhibition on BM-PC impairs their capacity to stimulate endothelial cell tube formation on matrigel and to promote endothelial monolayer recovery following wounding in vitro. Moreover, we show that activation of Notch pathway on BM-PC improved wound healing in vivo through angiogenesis induction. Conversely, inoculation of BM-PC pre-treated with a gamma secretase inhibitor (GSI) into wounded mice failed to induce angiogenesis at the wound site and did not promote wound healing, presumably due to a lower frequency of BM-PC at the wound area. Our data suggests that Notch pathway regulates BM-PC adhesion to ECM at sites of vascular repair and that it also regulates the capacity of BM-PC to stimulate angiogenesis and to promote wound healing. Drug targeting of the Notch pathway on BM-PC may thus represent a novel strategy to modulate neo-angiogenesis and vessel repair.

  4. Notch pathway modulation on bone marrow-derived vascular precursor cells regulates their angiogenic and wound healing potential.

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    Francisco Caiado

    Full Text Available Bone marrow (BM derived vascular precursor cells (BM-PC, endothelial progenitors are involved in normal and malignant angiogenesis, in ischemia and in wound healing. However, the mechanisms by which BM-PC stimulate the pre-existing endothelial cells at sites of vascular remodelling/recovery, and their contribution towards the formation of new blood vessels are still undisclosed. In the present report, we exploited the possibility that members of the Notch signalling pathway, expressed by BM-PC during endothelial differentiation, might regulate their pro-angiogenic or pro-wound healing properties. We demonstrate that Notch pathway modulates the adhesion of BM-PC to extracellular matrix (ECM in vitro via regulation of integrin alpha3beta1; and that Notch pathway inhibition on BM-PC impairs their capacity to stimulate endothelial cell tube formation on matrigel and to promote endothelial monolayer recovery following wounding in vitro. Moreover, we show that activation of Notch pathway on BM-PC improved wound healing in vivo through angiogenesis induction. Conversely, inoculation of BM-PC pre-treated with a gamma secretase inhibitor (GSI into wounded mice failed to induce angiogenesis at the wound site and did not promote wound healing, presumably due to a lower frequency of BM-PC at the wound area. Our data suggests that Notch pathway regulates BM-PC adhesion to ECM at sites of vascular repair and that it also regulates the capacity of BM-PC to stimulate angiogenesis and to promote wound healing. Drug targeting of the Notch pathway on BM-PC may thus represent a novel strategy to modulate neo-angiogenesis and vessel repair.

  5. Arabidopsis CPR5 independently regulates seed germination and postgermination arrest of development through LOX pathway and ABA signaling.

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    Guilan Gao

    Full Text Available The phytohormone abscisic acid (ABA and the lipoxygenases (LOXs pathway play important roles in seed germination and seedling growth and development. Here, we reported on the functional characterization of Arabidopsis CPR5 in the ABA signaling and LOX pathways. The cpr5 mutant was hypersensitive to ABA in the seed germination, cotyledon greening and root growth, whereas transgenic plants overexpressing CPR5 were insensitive. Genetic analysis demonstrated that CPR5 gene may be located downstream of the ABI1 in the ABA signaling pathway. However, the cpr5 mutant showed an ABA independent drought-resistant phenotype. It was also found that the cpr5 mutant was hypersensitive to NDGA and NDGA treatment aggravated the ABA-induced delay in the seed germination and cotyledon greening. Taken together, these results suggest that the CPR5 plays a regulatory role in the regulation of seed germination and early seedling growth through ABA and LOX pathways independently.

  6. The Hippo Pathway Regulates Stem Cells During Homeostasis and Regeneration of the Flatworm Macrostomum Lignano

    NARCIS (Netherlands)

    Demircan, Turan; Berezikov, Eugene

    2013-01-01

    The Hippo pathway orchestrates activity of stem cells during development and tissue regeneration and is crucial for controlling organ size. However, roles of the Hippo pathway in highly regenerative organisms, such as flatworms, are unknown. Here we show that knockdown of the Hippo pathway core gene

  7. The Hippo pathway regulates stem cells during homeostasis and regeneration of the flatworm Macrostomum lignano

    NARCIS (Netherlands)

    Demircan, T.; Berezikov, E.

    2013-01-01

    The Hippo pathway orchestrates activity of stem cells during development and tissue regeneration and is crucial for controlling organ size. However, roles of the Hippo pathway in highly regenerative organisms, such as flatworms, are unknown. Here we show that knockdown of the Hippo pathway core gene

  8. Obestatin enhances in vitro generation of pancreatic islets through regulation of developmental pathways.

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    Alessandra Baragli

    Full Text Available Availability of large amounts of in vitro generated β-cells may support replacement therapy in diabetes. However, methods to obtain β-cells from stem/progenitor cells are limited by inefficient endocrine differentiation. We have recently shown that the ghrelin gene product obestatin displays beneficial effects on pancreatic β-cell survival and function. Obestatin prevents β-cell apoptosis, preserves β-cell mass and stimulates insulin secretion in vitro and in vivo, in both normal and diabetic conditions. In the present study, we investigated whether obestatin may promote in vitro β-cell generation from mouse pancreatic islet-derived precursor cells. Treatment of cultured islets of Langerhans with obestatin (i enriched cells expressing the mesenchymal/neuronal marker nestin, which is associated with pancreatic precursors; (ii increased cell survival and reduced apoptosis during precursor selection; (iii promoted the generation of islet-like cell clusters (ICCs with increased insulin gene expression and C-peptide secretion. Furthermore, obestatin modulated the expression of fibroblast growth factor receptors (FGFRs, Notch receptors and neurogenin 3 (Ngn3 during islet-derived precursor cell selection and endocrine differentiation. These results indicate that obestatin improves the generation of functional β-cells/ICCs in vitro, suggesting implications for cell-based replacement therapy in diabetes. Moreover, obestatin may play a role in regulating pathways involved in pancreas development and regeneration.

  9. Downregulation of CDK-8 inhibits colon cancer hepatic metastasis by regulating Wnt/β-catenin pathway.

    Science.gov (United States)

    Cai, Wen-Song; Shen, Fei; Feng, Zhe; Chen, Ji-Wei; Liu, Qi-Cai; Li, Er-Mao; Xu, Bo; Cao, Jie

    2015-08-01

    Liver metastasis is a major cause of mortality from colon cancer. To investigate the role of cyclin-dependent kinase 8 (CDK8) in the progression of colon cancer hepatic metastasis. In this present study, human colon cancer HCT116 or HCT116-LUC-GFP cells were transfected with Lentiviral vector-mediated knockdown of CDK-8. After transfection, metastasis and invasion potential of colon cancer cell was investigated by wound healing and transwell invasion assays, respectively. A mice model of colon cancer liver metastases was established and observed with bioluminescence imaging. The protein expression of CDK-8, β-catenin, E2F1, MMP-7 and E-cadherin in liver tissues were detected by Western Blot. Our results revealed that lentiviral vector-mediated knockdown of CDK-8 inhibited metastasis and invasion of colon cancer cells in vitro and in vivo, respectively. Protein expression of CDK-8, β-catenin, MMP-7 and E-cadherin were inhibited, but protein expression of E2F1 was enhanced. In sum, our data provided compelling evidence that CDK-8 played a significant role in colon cancer hepatic metastasis by regulating the Wnt/β-catenin signal pathway and might sever as a potential therapeutic target for colon cancer patients.

  10. Pycnogenol attenuates atherosclerosis by regulating lipid metabolism through the TLR4-NF-κB pathway.

    Science.gov (United States)

    Luo, Hong; Wang, Jing; Qiao, Chenhui; Ma, Ning; Liu, Donghai; Zhang, Weihua

    2015-10-23

    Atherosclerosis is a leading cause of death worldwide and is characterized by lipid-laden foam cell formation. Recently, pycnogenol (PYC) has drawn much attention because of its prominent effect on cardiovascular disease (CVD). However, its protective effect against atherosclerosis and the underlying mechanism remains undefined. Here PYC treatment reduced areas of plaque and lipid deposition in atherosclerotic mice, concomitant with decreases in total cholesterol and triglyceride levels and increases in HDL cholesterol levels, indicating a potential antiatherosclerotic effect of PYC through the regulation of lipid levels. Additionally, PYC preconditioning markedly decreased foam cell formation and lipid accumulation in lipopolysaccharide (LPS)-stimulated human THP-1 monocytes. A mechanistic analysis indicated that PYC decreased the lipid-related protein expression of adipose differentiation-related protein (ADRP) and adipocyte lipid-binding protein (ALBP/aP2) in a dose-dependent manner. Further analysis confirmed that PYC attenuated LPS-induced lipid droplet formation via ADRP and ALBP expression through the Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) pathway, because pretreatment with anti-TLR4 antibody or a specific inhibitor of NF-κB (PDTC) strikingly mitigated the LPS-induced increase in ADRP and ALBP. Together, our results provide insight into the ability of PYC to attenuate bacterial infection-triggered pathological processes associated with atherosclerosis. Thus PYC may be a potential lead compound for the future development of antiatherosclerotic CVD therapy.

  11. Circadian and Dopaminergic Regulation of Fatty Acid Oxidation Pathway Genes in Retina and Photoreceptor Cells

    Science.gov (United States)

    Vancura, Patrick; Wolloscheck, Tanja; Baba, Kenkichi; Tosini, Gianluca; Iuvone, P. Michael; Spessert, Rainer

    2016-01-01

    The energy metabolism of the retina might comply with daily changes in energy demand and is impaired in diabetic retinopathy—one of the most common causes of blindness in Europe and the USA. The aim of this study was to investigate putative adaptation of energy metabolism in healthy and diabetic retina. Hence expression analysis of metabolic pathway genes was performed using quantitative polymerase chain reaction, semi-quantitative western blot and immunohistochemistry. Transcriptional profiling of key enzymes of energy metabolism identified transcripts of mitochondrial fatty acid β-oxidation enzymes, i.e. carnitine palmitoyltransferase-1α (Cpt-1α) and medium chain acyl-CoA dehydrogenase (Acadm) to display daily rhythms with peak values during daytime in preparations of the whole retina and microdissected photoreceptors. The cycling of both enzymes persisted in constant darkness, was dampened in mice deficient for dopamine D4 (D4) receptors and was altered in db/db mice—a model of diabetic retinopathy. The data of the present study are consistent with circadian clock-dependent and dopaminergic regulation of fatty acid oxidation in retina and its putative disturbance in diabetic retina. PMID:27727308

  12. Reciprocal regulation of cilia and autophagy via the MTOR and proteasome pathways.

    Science.gov (United States)

    Wang, Shixuan; Livingston, Man J; Su, Yunchao; Dong, Zheng

    2015-04-01

    Primary cilium is an organelle that plays significant roles in a number of cellular functions ranging from cell mechanosensation, proliferation, and differentiation to apoptosis. Autophagy is an evolutionarily conserved cellular function in biology and indispensable for cellular homeostasis. Both cilia and autophagy have been linked to different types of genetic and acquired human diseases. Their interaction has been suggested very recently, but the underlying mechanisms are still not fully understood. We examined autophagy in cells with suppressed cilia and measured cilium length in autophagy-activated or -suppressed cells. It was found that autophagy was repressed in cells with short cilia. Further investigation showed that MTOR activation was enhanced in cilia-suppressed cells and the MTOR inhibitor rapamycin could largely reverse autophagy suppression. In human kidney proximal tubular cells (HK2), autophagy induction was associated with cilium elongation. Conversely, autophagy inhibition by 3-methyladenine (3-MA) and chloroquine (CQ) as well as bafilomycin A1 (Baf) led to short cilia. Cilia were also shorter in cultured atg5-knockout (KO) cells and in atg7-KO kidney proximal tubular cells in mice. MG132, an inhibitor of the proteasome, could significantly restore cilium length in atg5-KO cells, being concomitant with the proteasome activity. Together, the results suggest that cilia and autophagy regulate reciprocally through the MTOR signaling pathway and ubiquitin-proteasome system.

  13. A TIGAR-regulated metabolic pathway is critical for protection of brain ischemia.

    Science.gov (United States)

    Li, Mei; Sun, Meiling; Cao, Lijuan; Gu, Jin-hua; Ge, Jianbin; Chen, Jieyu; Han, Rong; Qin, Yuan-Yuan; Zhou, Zhi-Peng; Ding, Yuqiang; Qin, Zheng-Hong

    2014-05-28

    TP53-induced glycolysis and apoptosis regulator (TIGAR) inhibits glycolysis and increases the flow of pentose phosphate pathway (PPP), which generates NADPH and pentose. We hypothesized that TIGAR plays a neuroprotective role in brain ischemia as neurons do not rely on glycolysis but are vulnerable to oxidative stress. We found that TIGAR was highly expressed in brain neurons and was rapidly upregulated in response to ischemia/reperfusion insult in a TP53-independent manner. Overexpression of TIGAR in normal mice with lentivirus reduced ischemic neuronal injury, whereas lentivirus-mediated TIGAR knockdown aggravated it. In cultured primary neurons, increasing TIGAR expression reduced oxygen and glucose deprivation (OGD)/reoxygenation-induced injury, whereas decreasing its expression worsened the injury. The glucose 6-phosphate dehydrogenase was upregulated in mouse and cellular models of stroke, and its upregulation was further enhanced by overexpression of TIGAR. Supplementation of NADPH also reduced ischemia/reperfusion brain injury and alleviated TIGAR knockdown-induced aggravation of ischemic injury. In animal and cellular stroke models, ischemia/reperfusion increased mitochondrial localization of TIGAR. OGD/reoxygenation-induced elevation of ROS, reduction of GSH, dysfunction of mitochondria, and activation of caspase-3 were rescued by overexpression of TIGAR or supplementation of NADPH, while knockdown of TIGAR aggravated these changes. Together, our results show that TIGAR protects ischemic brain injury via enhancing PPP flux and preserving mitochondria function, and thus may be a valuable therapeutic target for ischemic brain injury.

  14. Rare Copy Number Variants Identified Suggest the Regulating Pathways in Hypertension-Related Left Ventricular Hypertrophy.

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    Hoh Boon-Peng

    Full Text Available Left ventricular hypertrophy (LVH is an independent risk factor for cardiovascular morbidity and mortality, and a powerful predictor of adverse cardiovascular outcomes in the hypertensive patients. It has complex multifactorial and polygenic basis for its pathogenesis. We hypothesized that rare copy number variants (CNVs contribute to the LVH pathogenesis in hypertensive patients. Copy number variants (CNV were identified in 258 hypertensive patients, 95 of whom had LVH, after genotyping with a high resolution SNP array. Following stringent filtering criteria, we identified 208 rare, or private CNVs that were only present in our patients with hypertension related LVH. Preliminary findings from Gene Ontology and pathway analysis of this study confirmed the involvement of the genes known to be functionally involved in cardiac development and phenotypes, in line with previously reported transcriptomic studies. Network enrichment analyses suggested that the gene-set was, directly or indirectly, involved in the transcription factors regulating the "foetal cardiac gene programme" which triggered the hypertrophic cascade, confirming previous reports. These findings suggest that multiple, individually rare copy number variants altering genes may contribute to the pathogenesis of hypertension-related LVH. In summary, we have provided further supporting evidence that rare CNV could potentially impact this common and complex disease susceptibility with lower heritability.

  15. Negative regulation of TLR-signaling pathways by activating transcription factor-3.

    Science.gov (United States)

    Whitmore, Mark M; Iparraguirre, Amaya; Kubelka, Lindsey; Weninger, Wolfgang; Hai, Tsonwin; Williams, Bryan R G

    2007-09-15

    Activating transcription factor-3 (ATF3) is rapidly induced by LPS in mouse macrophages and regulates TLR4 responses. We show that ATF3 is rapidly induced by various TLRs in mouse macrophages and plasmacytoid dendritic cells (DCs), as well as plasmacytoid and myeloid subsets of human DCs. In primary macrophages from mice with a targeted deletion of the atf3 gene (ATF3-knockout (KO)), TLR-stimulated levels of IL-12 and IL-6 were elevated relative to responses in wild-type macrophages. Similarly, targeted deletion of atf3 correlated with enhanced responsiveness of myeloid DCs to TLR activation as measured by IL-12 secretion. Ectopic expression of ATF3 antagonized TLR-stimulated IL-12p40 activation in a reporter assay. In vivo, CpG-oligodeoxynucleotide, a TLR9 agonist, given i.p. to ATF3-KO mice resulted in enhanced cytokine production from splenocytes. Furthermore, while ATF3-KO mice challenged with a sublethal dose of PR8 influenza virus were delayed in body weight recovery in comparison to wild type, the ATF3-KO mice showed higher titers of serum neutralizing Ab against PR8 5 mo postinfection. Thus, ATF3 behaves as a negative regulatory transcription factor in TLR pathways and, accordingly, deficiency in atf3 alters responses to immunological challenges in vivo. ATF3 dysregulation merits further exploration in diseases such as type I diabetes and cancer, where altered innate immunity has been implicated in their pathogenesis.

  16. A karyopherin alpha2 nuclear transport pathway is regulated by glucose in hepatic and pancreatic cells.

    Science.gov (United States)

    Cassany, Aurélia; Guillemain, Ghislaine; Klein, Christophe; Dalet, Véronique; Brot-Laroche, Edith; Leturque, Armelle

    2004-01-01

    We studied the role of the karyopherin alpha2 nuclear import carrier (also known as importin alpha2) in glucose signaling. In mhAT3F hepatoma cells, GFP-karyopherin alpha2 accumulated massively in the cytoplasm within minutes of glucose extracellular addition and returned to the nucleus after glucose removal. In contrast, GFP-karyopherin alpha1 distribution was unaffected regardless of glucose concentration. Glucose increased GFP-karyopherin alpha2 nuclear efflux by a factor 80 and its shuttling by a factor 4. These glucose-induced movements were not due to glycolytic ATP production. The mechanism involved was leptomycin B-insensitive, but phosphatase- and energy-dependent. HepG2 and COS-7 cells displayed no glucose-induced GFP-karyopherin alpha2 movements. In pancreatic MIN-6 cells, the glucose-induced movements of karyopherin alpha2 and the stimulation of glucose-induced gene transcription were simultaneously lost between passages 28 and 33. Thus, extracellular glucose regulates a nuclear transport pathway by increasing the nuclear efflux and shuttling of karyopherin alpha2 in cells in which glucose can stimulate the transcription of sugar-responsive genes.

  17. NERP-2 regulates gastric acid secretion and gastric emptying via the orexin pathway.

    Science.gov (United States)

    Namkoong, Cherl; Toshinai, Koji; Waise, T M Zaved; Sakoda, Hideyuki; Sasaki, Kazuki; Ueta, Yoichi; Kim, Min-Seon; Minamino, Naoto; Nakazato, Masamitsu

    2017-02-16

    Neuroendocrine regulatory peptide (NERP)-2 is derived from a distinct region of VGF, a neurosecretory protein originally identified as a product of a nerve growth factor-responsive gene in rat PC12 cells. Colocalization of NERP-2 with orexin-A in the lateral hypothalamus increases orexin-A-induced feeding and energy expenditure in both rats and mice. Orexigenic and anorectic peptides in the hypothalamus modulate gastric function. In this study, we investigated the effect of NERP-2 on gastric function in rats. Intracerebroventricular administration of NERP-2 to rats increased gastric acid secretion and gastric emptying, whereas peripheral administration did not affect gastric function. NERP-2-induced gastric acid secretion and gastric emptying were blocked by an orexin 1 receptor antagonist, SB334867. NERP-2 also induced Fos expression in the lateral hypothalamus and the dorsomotor nucleus of the vagus X, which are key sites in the central nervous system for regulation of gastric function. Atropine, a blocker of vagal efferent signal transduction, completely blocked NERP-2-induced gastric acid secretion. These results demonstrate that central administration of NERP-2 activates the orexin pathway, resulting in elevated gastric acid secretion and gastric emptying.

  18. Abiotic Stresses: Insight into Gene Regulation and Protein Expression in Photosynthetic Pathways of Plants

    Directory of Open Access Journals (Sweden)

    Mohammad-Zaman Nouri

    2015-08-01

    Full Text Available Global warming and climate change intensified the occurrence and severity of abiotic stresses that seriously affect the growth and development of plants,especially, plant photosynthesis. The direct impact of abiotic stress on the activity of photosynthesis is disruption of all photosynthesis components such as photosystem I and II, electron transport, carbon fixation, ATP generating system and stomatal conductance. The photosynthetic system of plants reacts to the stress differently, according to the plant type, photosynthetic systems (C3 or C4, type of the stress, time and duration of the occurrence and several other factors. The plant responds to the stresses by a coordinate chloroplast and nuclear gene expression. Chloroplast, thylakoid membrane, and nucleus are the main targets of regulated proteins and metabolites associated with photosynthetic pathways. Rapid responses of plant cell metabolism and adaptation to photosynthetic machinery are key factors for survival of plants in a fluctuating environment. This review gives a comprehensive view of photosynthesis-related alterations at the gene and protein levels for plant adaptation or reaction in response to abiotic stress.

  19. Drosophila MOF regulates DIAP1 and induces apoptosis in a JNK dependent pathway.

    Science.gov (United States)

    Pushpavalli, Sreerangam N C V L; Sarkar, Arpita; Ramaiah, M Janaki; Koteswara Rao, G; Bag, Indira; Bhadra, Utpal; Pal-Bhadra, Manika

    2016-03-01

    Histone modulations have been implicated in various cellular and developmental processes where in Drosophila Mof is involved in acetylation of H4K16. Reduction in the size of larval imaginal discs is observed in the null mutants of mof with increased apoptosis. Deficiency involving Hid, Reaper and Grim [H99] alleviated mof (RNAi) induced apoptosis in the eye discs. mof (RNAi) induced apoptosis leads to activation of caspases which is suppressed by over expression of caspase inhibitors like P35 and Diap1 clearly depicting the role of caspases in programmed cell death. Also apoptosis induced by knockdown of mof is rescued by JNK mutants of bsk and tak1 indicating the role of JNK in mof (RNAi) induced apoptosis. The adult eye ablation phenotype produced by ectopic expression of Hid, Rpr and Grim, was restored by over expression of Mof. Accumulation of Mof at the Diap1 promoter 800 bp upstream of the transcription start site in wild type larvae is significantly higher (up to twofolds) compared to mof (1) mutants. This enrichment coincides with modification of histone H4K16Ac indicating an induction of direct transcriptional up regulation of Diap1 by Mof. Based on these results we propose that apoptosis triggered by mof (RNAi) proceeds through a caspase-dependent and JNK mediated pathway.

  20. Octopamine Neuromodulation Regulates Gr32a-Linked Aggression and Courtship Pathways in Drosophila Males

    Science.gov (United States)

    Andrews, Jonathan C.; Fernández, María Paz; Yu, Qin; Leary, Greg P.; Leung, Adelaine K. W.; Kavanaugh, Michael P.; Kravitz, Edward A.; Certel, Sarah J.

    2014-01-01

    Chemosensory pheromonal information regulates aggression and reproduction in many species, but how pheromonal signals are transduced to reliably produce behavior is not well understood. Here we demonstrate that the pheromonal signals detected by Gr32a-expressing chemosensory neurons to enhance male aggression are filtered through octopamine (OA, invertebrate equivalent of norepinephrine) neurons. Using behavioral assays, we find males lacking both octopamine and Gr32a gustatory receptors exhibit parallel delays in the onset of aggression and reductions in aggression. Physiological and anatomical experiments identify Gr32a to octopamine neuron synaptic and functional connections in the suboesophageal ganglion. Refining the Gr32a-expressing population indicates that mouth Gr32a neurons promote male aggression and form synaptic contacts with OA neurons. By restricting the monoamine neuron target population, we show that three previously identified OA-FruM neurons involved in behavioral choice are among the Gr32a-OA connections. Our findings demonstrate that octopaminergic neuromodulatory neurons function as early as a second-order step in this chemosensory-driven male social behavior pathway. PMID:24852170

  1. Octopamine neuromodulation regulates Gr32a-linked aggression and courtship pathways in Drosophila males.

    Directory of Open Access Journals (Sweden)

    Jonathan C Andrews

    2014-05-01

    Full Text Available Chemosensory pheromonal information regulates aggression and reproduction in many species, but how pheromonal signals are transduced to reliably produce behavior is not well understood. Here we demonstrate that the pheromonal signals detected by Gr32a-expressing chemosensory neurons to enhance male aggression are filtered through octopamine (OA, invertebrate equivalent of norepinephrine neurons. Using behavioral assays, we find males lacking both octopamine and Gr32a gustatory receptors exhibit parallel delays in the onset of aggression and reductions in aggression. Physiological and anatomical experiments identify Gr32a to octopamine neuron synaptic and functional connections in the suboesophageal ganglion. Refining the Gr32a-expressing population indicates that mouth Gr32a neurons promote male aggression and form synaptic contacts with OA neurons. By restricting the monoamine neuron target population, we show that three previously identified OA-Fru(M neurons involved in behavioral choice are among the Gr32a-OA connections. Our findings demonstrate that octopaminergic neuromodulatory neurons function as early as a second-order step in this chemosensory-driven male social behavior pathway.

  2. Apigenin induces the apoptosis and regulates MAPK signaling pathways in mouse macrophage ANA-1 cells.

    Science.gov (United States)

    Liao, Yuexia; Shen, Weigan; Kong, Guimei; Lv, Houning; Tao, Wenhua; Bo, Ping

    2014-01-01

    Apigenin is a naturally occurring plant flavonoid that possesses antioxidant, anti-cancer and anti-inflammatory properties. However, there are few reports has been done on the ability of apigenin to induce apoptosis in macrophages. In this study, mouse macrophage ANA-1 cells were incubated with different concentrations of apigenin. The cell viability was determined by an MTT assay. The cell apoptosis were analyzed by flow cytometric analysis. Apoptosis were also analyzed using a TUNEL assay and a DNA ladder. The level of intracellular ROS was detected using a dichlorofluorescein -diacetate probe. The expression levels of apoptosis-related proteins were detected by western blot analysis. The results showed that apigenin decreased the viability of ANA-1 cells and induced apoptosis in a dose- and time-dependent manner. Apigenin increased the level of intracellular ROS, downregulated the expression of Bcl-2 and upregulated the expression of caspase-3 and caspase-8 in ANA-1 cells. Furthermore, apigenin downregulated the expression of phospho-ERK and phospho-JNK, upregulated the expression of phospho-p38 and had no significant effect on the expression of Bax, ERK, JNK and p38. The results suggested that apigenin induced cell apoptosis in mouse macrophage ANA-1 cells may via increasing intracellular ROS, regulating the MAPK pathway, and then inhibiting Bcl-2 expression.

  3. RNA sequencing analysis of human podocytes reveals glucocorticoid regulated gene networks targeting non-immune pathways

    Science.gov (United States)

    Jiang, Lulu; Hindmarch, Charles C. T.; Rogers, Mark; Campbell, Colin; Waterfall, Christy; Coghill, Jane; Mathieson, Peter W.; Welsh, Gavin I.

    2016-01-01

    Glucocorticoids are steroids that reduce inflammation and are used as immunosuppressive drugs for many diseases. They are also the mainstay for the treatment of minimal change nephropathy (MCN), which is characterised by an absence of inflammation. Their mechanisms of action remain elusive. Evidence suggests that immunomodulatory drugs can directly act on glomerular epithelial cells or ‘podocytes’, the cell type which is the main target of injury in MCN. To understand the nature of glucocorticoid effects on non-immune cell functions, we generated RNA sequencing data from human podocyte cell lines and identified the genes that are significantly regulated in dexamethasone-treated podocytes compared to vehicle-treated cells. The upregulated genes are of functional relevance to cytoskeleton-related processes, whereas the downregulated genes mostly encode pro-inflammatory cytokines and growth factors. We observed a tendency for dexamethasone-upregulated genes to be downregulated in MCN patients. Integrative analysis revealed gene networks composed of critical signaling pathways that are likely targeted by dexamethasone in podocytes. PMID:27774996

  4. The M-type receptor PLA2R regulates senescence through the p53 pathway.

    Science.gov (United States)

    Augert, Arnaud; Payré, Christine; de Launoit, Yvan; Gil, Jesus; Lambeau, Gérard; Bernard, David

    2009-03-01

    Senescence is a stable proliferative arrest induced by various stresses such as telomere erosion, oncogenic or oxidative stress. Compelling evidence suggests that it acts as a barrier against tumour development. Describing new mechanisms that favour an escape from senescence can thus reveal new insights into tumorigenesis. To identify new genes controlling the senescence programme, we performed a loss-of-function genetic screen in primary human fibroblasts. We report that knockdown of the M-type receptor PLA2R (phospholipase A2 receptor) prevents the onset of replicative senescence and diminishes stress-induced senescence. Interestingly, expression of PLA2R increases during replicative senescence, and its ectopic expression results in premature senescence. We show that PLA2R regulates senescence in a reactive oxygen species-DNA damage-p53-dependent manner. Taken together, our study identifies PLA2R as a potential new tumour suppressor gene crucial in the induction of cellular senescence through the activation of the p53 pathway.

  5. The Parkinson's disease-associated genes ATP13A2 and SYT11 regulate autophagy via a common pathway.

    Science.gov (United States)

    Bento, Carla F; Ashkenazi, Avraham; Jimenez-Sanchez, Maria; Rubinsztein, David C

    2016-06-09

    Forms of Parkinson's disease (PD) are associated with lysosomal and autophagic dysfunction. ATP13A2, which is mutated in some types of early-onset Parkinsonism, has been suggested as a regulator of the autophagy-lysosome pathway. However, little is known about the ATP13A2 effectors and how they regulate this pathway. Here we show that ATP13A2 depletion negatively regulates another PD-associated gene (SYT11) at both transcriptional and post-translational levels. Decreased SYT11 transcription is controlled by a mechanism dependent on MYCBP2-induced ubiquitination of TSC2, which leads to mTORC1 activation and decreased TFEB-mediated transcription of SYT11, while increased protein turnover is regulated by SYT11 ubiquitination and degradation. Both mechanisms account for a decrease in the levels of SYT11, which, in turn, induces lysosomal dysfunction and impaired degradation of autophagosomes. Thus, we propose that ATP13A2 and SYT11 form a new functional network in the regulation of the autophagy-lysosome pathway, which is likely to contribute to forms of PD-associated neurodegeneration.

  6. Urothelial endocytic vesicle recycling and lysosomal degradative pathway regulated by lipid membrane composition.

    Science.gov (United States)

    Grasso, E J; Calderón, R O

    2013-02-01

    The urothelium, a specialized epithelium that covers the mucosa cell surface of the urinary bladder, undergoes dramatic morphological changes during the micturition cycle that involve a membrane apical traffic. This traffic was first described as a lysosomal pathway, in addition to the known endocytosis/exocytosis membrane recycling. In an attempt to understand the role of membrane lipid composition in those effects, we previously described the lipid-dependent leakage of the endocytosed vesicle content. In this work, we demonstrated clear differences in the traffic of both the fluid probe and the membrane-bound probe in urothelial umbrella cells by using spectrofluorometry and/or confocal and epifluorescence microscopy. Different membrane lipid compositions were established by using three diet formulae enriched in oleic acid, linoleic acid and a commercial formula. Between three and five animals for each dietary treatment were used for each analysis. The decreased endocytosis of both fluid and membrane-bound probes (approximately 32 and 49 % lower, respectively) in oleic acid-derived umbrella cells was concomitant with an increased recycling (approximately 4.0 and 3.7 times, respectively) and diminished sorting to the lysosome (approximately 23 and 37 %, respectively) when compared with the control umbrella cells. The higher intravesicular pH and the impairment of the lysosomal pathway of oleic acid diet-derived vesicles compared to linoleic acid diet-derived vesicles and control diet-derived vesicles correlate with our findings of a lower V-ATPase activity previously reported. We integrated the results obtained in the present and previous work to determine the sorting of endocytosed material (fluid and membrane-bound probes) into the different cell compartments. Finally, the weighted average effect of the individual alterations on the intracellular distribution was evaluated. The results shown in this work add evidences for the modulatory role of the membrane

  7. Actin-Capping Protein and the Hippo pathway regulate F-actin and tissue growth in Drosophila.

    Science.gov (United States)

    Fernández, Beatriz García; Gaspar, Pedro; Brás-Pereira, Catarina; Jezowska, Barbara; Rebelo, Sofia Raquel; Janody, Florence

    2011-06-01

    The conserved Hippo tumor suppressor pathway is a key kinase cascade that controls tissue growth by regulating the nuclear import and activity of the transcription co-activator Yorkie. Here, we report that the actin-Capping Protein αβ heterodimer, which regulates actin polymerization, also functions to suppress inappropriate tissue growth by inhibiting Yorkie activity. Loss of Capping Protein activity results in abnormal accumulation of apical F-actin, reduced Hippo pathway activity and the ectopic expression of several Yorkie target genes that promote cell survival and proliferation. Reduction of two other actin-regulatory proteins, Cofilin and the cyclase-associated protein Capulet, cause abnormal F-actin accumulation, but only the loss of Capulet, like that of Capping Protein, induces ectopic Yorkie activity. Interestingly, F-actin also accumulates abnormally when Hippo pathway activity is reduced or abolished, independently of Yorkie activity, whereas overexpression of the Hippo pathway component expanded can partially reverse the abnormal accumulation of F-actin in cells depleted for Capping Protein. Taken together, these findings indicate a novel interplay between Hippo pathway activity and actin filament dynamics that is essential for normal growth control.

  8. Mechanism for regulation of the putrescine utilization pathway by the transcription factor PuuR in Escherichia coli K-12.

    Science.gov (United States)

    Nemoto, Naoki; Kurihara, Shin; Kitahara, Yuzuru; Asada, Kei; Kato, Kenji; Suzuki, Hideyuki

    2012-07-01

    In Escherichia coli, putrescine is metabolized to succinate for use as a carbon and nitrogen source by the putrescine utilization pathway (Puu pathway). One gene in the puu gene cluster encodes a transcription factor, PuuR, which has a helix-turn-helix DNA-binding motif. DNA microarray analysis of an E. coli puuR mutant, in which three amino acid residues in the helix-turn-helix DNA binding motif of PuuR were mutated to alanine to eliminate DNA binding of PuuR, suggested that PuuR is a negative regulator of puu genes. Results of gel shift and DNase I footprint analyses suggested that PuuR binds to the promoter regions of puuA and puuD. The binding of wild-type PuuR to a DNA probe containing PuuR recognition sites was diminished with increasing putrescine concentrations in vitro. These results suggest that PuuR regulates the intracellular putrescine concentration by the transcriptional regulation of genes in the Puu pathway, including puuR itself. The puu gene cluster is found in E. coli and closely related enterobacteria, but this gene cluster is uncommon in other bacterial groups. E. coli and related enterobacteria may have gained the Puu pathway as an adaptation for survival in the mammalian intestine, an environment in which polyamines exist at relatively high concentrations.

  9. TOR Pathway-Mediated Juvenile Hormone Synthesis Regulates Nutrient-Dependent Female Reproduction in Nilaparvata lugens (Stål).

    Science.gov (United States)

    Lu, Kai; Chen, Xia; Liu, Wen-Ting; Zhou, Qiang

    2016-03-28

    The "target of rapamycin" (TOR) nutritional signaling pathway and juvenile hormone (JH) regulation of vitellogenesis has been known for a long time. However, the interplay between these two pathways regulating vitellogenin (Vg) expression remains obscure. Here, we first demonstrated the key role of amino acids (AAs) in activation of Vg synthesis and egg development in Nilaparvata lugens using chemically defined artificial diets. AAs induced the expression of TOR and S6K (S6 kinase), whereas RNAi-mediated silencing of these two TOR pathway genes and rapamycin application strongly inhibited the AAs-induced Vg synthesis. Furthermore, knockdown of Rheb (Ras homologue enriched in brain), TOR, S6K and application of rapamycin resulted in a dramatic reduction in the mRNA levels of jmtN (juvenile hormone acid methyltransferase, JHAMT). Application of JH III on the RNAi (Rheb and TOR) and rapamycin-treated females partially rescued the Vg expression. Conversely, knockdown of either jmtN or met (methoprene-tolerant, JH receptor) and application of JH III had no effects on mRNA levels of Rheb, TOR and S6K and phosphorylation of S6K. In summary, our results demonstrate that the TOR pathway induces JH biosynthesis that in turn regulates AAs-mediated Vg synthesis in N. lugens.

  10. The Ras/Raf/MEK/Extracellular Signal-Regulated Kinase Pathway Induces Autocrine-Paracrine Growth Inhibition via the Leukemia Inhibitory Factor/JAK/STAT Pathway

    OpenAIRE

    Park, Jong-In; Strock, Christopher J.; Ball, Douglas W.; Nelkin, Barry D.

    2003-01-01

    Sustained activation of the Ras/Raf/MEK/extracellular signal-regulated kinase (ERK) pathway can lead to cell cycle arrest in many cell types. We have found, with human medullary thyroid cancer (MTC) cells, that activated Ras or c-Raf-1 can induce growth arrest by producing and secreting an autocrine-paracrine factor. This protein was purified from cell culture medium conditioned by Raf-activated MTC cells and was identified by mass spectrometry as leukemia inhibitory factor (LIF). LIF express...

  11. Angelica polymorpha Maxim Induces Apoptosis of Human SH-SY5Y Neuroblastoma Cells by Regulating an Intrinsic Caspase Pathway.

    Science.gov (United States)

    Rahman, Md Ataur; Bishayee, Kausik; Huh, Sung-Oh

    2016-02-01

    Angelica polymorpha Maxim root extract (APRE) is a popular herbal medicine used for treating stomachache, abdominal pain, stomach ulcers, and rheumatism; however the effect of APRE on cancer cells has not yet been explored. Here, we examined APRE cytotoxicity seen on target neuroblastoma cells (NB) using cell viability assays, DAPI visualization of fragmented DNA, and Western blotting analysis of candidate signaling pathways involved in proliferation and apoptosis. We demonstrated that APRE reduced cell viability in NB to a greater extent than in fibroblast cells. In addition, we found that APRE could inhibit the three classes of MAPK proteins and could also down-regulate the PI3K/AKT/GSK-3β activity all being relevant for proliferation and survival. APRE could also up-regulate Bax expression and down-regulate Bcl-2 and Mcl-1. With APRE treatment, depolarization of mitochondria membrane potential and activation of caspase-3 was demonstrated in the SH-SY5Y cells. We could not found increased activity of death receptor and caspase-8 as markers of the extrinsic apoptosis pathway for the APRE treated cells. In presence of a caspase-3 siRNA and a pan-caspase inhibitor, APRE could not reduce the viability of NB cells to a significant degree. So we predicted that with APRE, the intrinsic pathway was solely responsible for inducing apoptosis as we also showed that the non-caspase autophagy pathway or ER stress-ROS mediated pathways were not involved. These findings demonstrate that an intrinsic mitochondria-mediated apoptosis pathway mediates the apoptotic effects of APRE on SH-SY5Y cells, and that APRE shows promise as a novel agent for neuroblastoma therapy.

  12. Tyrosine Phosphorylation Based Homo-dimerization of Arabidopsis RACK1A Proteins Regulates Oxidative Stress Signaling Pathways in Yeast.

    Science.gov (United States)

    Sabila, Mercy; Kundu, Nabanita; Smalls, Deana; Ullah, Hemayet

    2016-01-01

    Scaffold proteins are known as important cellular regulators that can interact with multiple proteins to modulate diverse signal transduction pathways. RACK1 (Receptor for Activated C Kinase 1) is a WD-40 type scaffold protein, conserved in eukaryotes, from Chlamydymonas to plants and humans, plays regulatory roles in diverse signal transduction and stress response pathways. RACK1 in humans has been implicated in myriads of neuropathological diseases including Alzheimer and alcohol addictions. Model plant Arabidopsis thaliana genome maintains three different RACK1 genes termed RACK1A, RACK1B, and RACK1C with a very high (85-93%) sequence identity among them. Loss of function mutation in Arabidopsis indicates that RACK1 proteins regulate diverse environmental stress signaling pathways including drought and salt stress resistance pathway. Recently deduced crystal structure of Arabidopsis RACK1A- very first among all of the RACK1 proteins, indicates that it can potentially be regulated by post-translational modifications, like tyrosine phosphorylations and sumoylation at key residues. Here we show evidence that RACK1A proteins, depending on diverse environmental stresses, are tyrosine phosphorylated. Utilizing site-directed mutagenesis of key tyrosine residues, it is found that tyrosine phosphorylation can potentially dictate the homo-dimerization of RACK1A proteins. The homo-dimerized RACK1A proteins play a role in providing UV-B induced oxidative stress resistance. It is proposed that RACK1A proteins ability to function as scaffold protein may potentially be regulated by the homo-dimerized RACK1A proteins to mediate diverse stress signaling pathways.

  13. The regulation of p53 up-regulated modulator of apoptosis by JNK/c-Jun pathway in β-amyloid-induced neuron death.

    Science.gov (United States)

    Akhter, Rumana; Sanphui, Priyankar; Das, Hrishita; Saha, Pampa; Biswas, Subhas Chandra

    2015-09-01

    Neuronal loss in selective areas of brain underlies the pathology of Alzheimer's disease (AD). Recent evidences place oligomeric β-amyloid (Aβ) central to the disease. However, mechanism of neuron death in response to Aβ remains elusive. Activation of the c-Jun N-terminal kinase (JNK) pathway and induction of the AP-1 transcription factor c-Jun are reported in AD. However, targets of JNK/c-Jun in Aβ-induced neuron death are mostly unknown. Our study shows that pro-apoptotic proteins, Bim (Bcl-2 interacting mediator of cell death) and Puma (p53 up-regulated modulator of apoptosis) are targets of c-Jun in Aβ-treated neurons. We demonstrate that the JNK/c-Jun pathway is activated, in cultures of cortical neurons following treatment with oligomeric Aβ and in AD transgenic mice, and that inhibition of this pathway by selective inhibitor blocks induction of Puma by Aβ. We also find that both JNK and p53 pathways co-operatively regulate Puma expression in Aβ-treated neurons. Moreover, we identified a novel AP1-binding site on rat puma gene which is necessary for direct binding of c-Jun with Puma promoter. Finally, we find that knocking down of c-Jun by siRNA provides significant protection from Aβ toxicity and that induction of Bim and Puma by Aβ in neurons requires c-Jun. Taken together, our results suggest that both Bim and Puma are target of c-Jun and elucidate the intricate regulation of Puma expression by JNK/c-Jun and p53 pathways in neurons upon Aβ toxicity. JNK/c-Jun pathway is shown to be activated in neurons of the Alzheimer's disease (AD) brain and plays a vital role in neuron death in AD models. However, downstream targets of c-Jun in this disease have not been thoroughly elucidated. Our study shows that two important pro-apoptotic proteins, Bim (Bcl-2 interacting mediator of cell death) and Puma (p53 up-regulated modulator of apoptosis) are targets of c-Jun in Aβ-treated neurons. We demonstrate that the JNK/c-jun pathway is activated, in cultures

  14. Pathway-level acceleration of glycogen catabolism by a response regulator in the cyanobacterium Synechocystis species PCC 6803.

    Science.gov (United States)

    Osanai, Takashi; Oikawa, Akira; Numata, Keiji; Kuwahara, Ayuko; Iijima, Hiroko; Doi, Yoshiharu; Saito, Kazuki; Hirai, Masami Yokota

    2014-04-01

    Response regulators of two-component systems play pivotal roles in the transcriptional regulation of responses to environmental signals in bacteria. Rre37, an OmpR-type response regulator, is induced by nitrogen depletion in the unicellular cyanobacterium Synechocystis species PCC 6803. Microarray and quantitative real-time polymerase chain reaction analyses revealed that genes related to sugar catabolism and nitrogen metabolism were up-regulated by rre37 overexpression. Protein levels of GlgP(slr1367), one of the two glycogen phosphorylases, in the rre37-overexpressing strain were higher than those of the parental wild-type strain under both nitrogen-replete and nitrogen-depleted conditions. Glycogen amounts decreased to less than one-tenth by rre37 overexpression under nitrogen-replete conditions. Metabolome analysis revealed that metabolites of the sugar catabolic pathway and amino acids were altered in the rre37-overexpressing strain after nitrogen depletion. These results demonstrate that Rre37 is a pathway-level regulator that activates the metabolic flow from glycogen to polyhydroxybutyrate and the hybrid tricarboxylic acid and ornithine cycle, unraveling the mechanism of the transcriptional regulation of primary metabolism in this unicellular cyanobacterium.

  15. Autoimmune Regulator Expression in DC2.4 Cells Regulates the NF-κB Signaling and Cytokine Expression of the Toll-Like Receptor 3 Pathway

    Directory of Open Access Journals (Sweden)

    Jitong Sun

    2016-12-01

    Full Text Available Autoimmune regulator (Aire mutations result in autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED, which manifests as multi-organ autoimmunity and chronic mucocutaneous candidiasis (CMC. Indendritic cells (DCs, pattern recognition receptors (PRR, such as Toll-like receptors (TLRs, are closely involved in the recognition of various pathogens, activating the intercellular signaling pathway, followed by the activation of transcription factors and the expression of downstream genes, which take part in mediating the immune response and maintaining immune tolerance. In this study, we found that Aire up-regulated TLR3 expression and modulated the downstream cytokine expression and nuclear factor-κB (NF-κB of the TLR3 signaling pathway.

  16. Minimal and inducible regulation of tissue factor pathway inhibitor-2 in human gliomas.

    Science.gov (United States)

    Konduri, Santhi D; Osman, Francis Ali; Rao, Chilukuri N; Srinivas, Harish; Yanamandra, Niranjan; Tasiou, Anastasia; Dinh, Dzung H; Olivero, William C; Gujrati, Meena; Foster, Donald C; Kisiel, Walter; Kouraklis, Gregory; Rao, Jasti S

    2002-01-31

    Tissue factor pathway inhibitor-2 (TFPI-2), a serine protease inhibitor abundant in the extra cellular matrix, is highly expressed in non-invasive cells but undetectable levels in highly invasive human glioma cells. The mechanisms responsible for its transcriptional regulation are not well elucidated. In this study, we made several deletion constructs from a 3.6 kb genomic fragment from Hs683 cells containing the 5'-flanking region of the TFPI-2 gene, transiently transfected with these constructs into non-invasive (Hs683) and highly invasive (SNB19) human glioma cells, and assessed their expression by using a luciferase reporter gene. Three constructs showed high promoter activity (pTF5, -670 to +1; pTF6, -312 to +1; pTF2, -1511 to +1). Another construct, pTF8 (-81 to +1), showed no activity. PTF9, a variant of pTF5 in which a further 231 bp fragment (-312 to -81) was deleted, from the [-670 to +1] pTF5 region, also showed no promoter activity. Hence, (-312 to -81) this region is essential for the transcription of TFPI-2 in glioma cells. Sequencing of this promoter region revealed that it has a high G+C content, contains potential SP1 and AP1 binding motifs, and lacks canonical TATA and CAAT boxes immediately upstream of the major transcriptional initiation site, although CAAT boxes were found about -3000 bp upstream of the transcription start site. We also found a strong repressor in the region between -927 to -1181, upstream of the major transcriptional initiation site, followed by positive elements or enhancers between -1511 to -1181. These positive elements masked the silencer effect. Finally TFPI-2 was induced in Hs683 cells transfected with the pTF6 construct (-312 to +1) and stimulated with phorbol-12-myristate-13-acetate (PMA). We conclude that the -312 to +1 region is critical for the minimal and inducible regulation of TFPI-2 in non-invasive (Hs683) and highly invasive (SNB19) human glioma cell lines.

  17. A G-protein β subunit, AGB1, negatively regulates the ABA response and drought tolerance by down-regulating AtMPK6-related pathway in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Dong-bei Xu

    Full Text Available Heterotrimeric G-proteins are versatile regulators involved in diverse cellular processes in eukaryotes. In plants, the function of G-proteins is primarily associated with ABA signaling. However, the downstream effectors and the molecular mechanisms in the ABA pathway remain largely unknown. In this study, an AGB1 mutant (agb1-2 was found to show enhanced drought tolerance, indicating that AGB1 might negatively regulate drought tolerance in Arabidopsis. Data showed that AGB1 interacted with protein kinase AtMPK6 that was previously shown to phosphorylate AtVIP1, a transcription factor responding to ABA signaling. Our study found that transcript levels of three ABA responsive genes, AtMPK6, AtVIP1 and AtMYB44 (downstream gene of AtVIP1, were significantly up-regulated in agb1-2 lines after ABA or drought treatments. Other ABA-responsive and drought-inducible genes, such as RD29A (downstream gene of AtMYB44, were also up-regulated in agb1-2 lines. Furthermore, overexpression of AtVIP1 resulted in hypersensitivity to ABA at seed germination and seedling stages, and significantly enhanced drought tolerance in transgenic plants. These results suggest that AGB1 was involved in the ABA signaling pathway and drought tolerance in Arabidopsis through down-regulating the AtMPK6, AtVIP1 and AtMYB44 cascade.

  18. A G-protein β subunit, AGB1, negatively regulates the ABA response and drought tolerance by down-regulating AtMPK6-related pathway in Arabidopsis.

    Science.gov (United States)

    Xu, Dong-bei; Chen, Ming; Ma, Ya-nan; Xu, Zhao-shi; Li, Lian-cheng; Chen, Yao-feng; Ma, You-zhi

    2015-01-01

    Heterotrimeric G-proteins are versatile regulators involved in diverse cellular processes in eukaryotes. In plants, the function of G-proteins is primarily associated with ABA signaling. However, the downstream effectors and the molecular mechanisms in the ABA pathway remain largely unknown. In this study, an AGB1 mutant (agb1-2) was found to show enhanced drought tolerance, indicating that AGB1 might negatively regulate drought tolerance in Arabidopsis. Data showed that AGB1 interacted with protein kinase AtMPK6 that was previously shown to phosphorylate AtVIP1, a transcription factor responding to ABA signaling. Our study found that transcript levels of three ABA responsive genes, AtMPK6, AtVIP1 and AtMYB44 (downstream gene of AtVIP1), were significantly up-regulated in agb1-2 lines after ABA or drought treatments. Other ABA-responsive and drought-inducible genes, such as RD29A (downstream gene of AtMYB44), were also up-regulated in agb1-2 lines. Furthermore, overexpression of AtVIP1 resulted in hypersensitivity to ABA at seed germination and seedling stages, and significantly enhanced drought tolerance in transgenic plants. These results suggest that AGB1 was involved in the ABA signaling pathway and drought tolerance in Arabidopsis through down-regulating the AtMPK6, AtVIP1 and AtMYB44 cascade.

  19. The Heparan and Heparin Metabolism Pathway is Involved in Regulation of Fatty Acid Composition

    Directory of Open Access Journals (Sweden)

    Zhihua Jiang, Jennifer J. Michal, Xiao-Lin Wu, Zengxiang Pan, Michael D. MacNeil

    2011-01-01

    Full Text Available Six genes involved in the heparan sulfate and heparin metabolism pathway, DSEL (dermatan sulfate epimerase-like, EXTL1 (exostoses (multiple-like 1, HS6ST1 (heparan sulfate 6-O-sulfotransferase 1, HS6ST3 (heparan sulfate 6-O-sulfotransferase 3, NDST3 (N-deacetylase/N-sulfotransferase (heparan glucosaminyl 3, and SULT1A1 (sulfotransferase family, cytosolic, 1A, phenol-preferring, member 1, were investigated for their associations with muscle lipid composition using cattle as a model organism. Nineteen single nucleotide polymorphisms (SNPs/multiple nucleotide length polymorphisms (MNLPs were identified in five of these six genes. Six of these mutations were then genotyped on 246 Wagyu x Limousin F2 animals, which were measured for 5 carcass, 6 eating quality and 8 fatty acid composition traits. Association analysis revealed that DSEL, EXTL1 and HS6ST1 significantly affected two stearoyl-CoA desaturase activity indices, the amount of conjugated linoleic acid (CLA, and the relative amount of saturated fatty acids (SFA and monounsaturated fatty acids (MUFA in skeletal muscle (P<0.05. In particular, HS6ST1 joined our previously reported SCD1 and UQCRC1 genes to form a three gene network for one of the stearoyl-CoA desaturase activity indices. These results provide evidence that genes involved in heparan sulfate and heparin metabolism are also involved in regulation of lipid metabolism in bovine muscle. Whether the SNPs affected heparan sulfate proteoglycan structure is unknown and warrants further investigation.

  20. Signal transduction pathways regulating cyclooxygenase-2 expression: potential molecular targets for chemoprevention.

    Science.gov (United States)

    Chun, Kyung-Soo; Surh, Young-Joon

    2004-09-15

    Expression of cyclooxygenase-2 (COX-2) has been reported to be elevated in human colorectal adenocarcinoma and other tumors, including those of breast, cervical, prostate, and lung. Genetic knock-out or pharmacological inhibition of COX-2 has been shown to protect against experimentally-induced carcinogenesis. Results from epidemiological and laboratory studies indicate that regular intake of selective COX-2 inhibitors reduces the risk of several forms of human malignancies. Thus, it is conceivable that targeted inhibition of abnormally or improperly elevated COX-2 provides one of the most effective and promising strategies for cancer chemoprevention. The COX-2 promoter contains a TATA box and binding sites for several transcription factors including nuclear factor-kappaB (NF-kappaB), nuclear factor for interleukin-6/CCAAT enhancer-binding protein (NF-IL6/C/EBP) and cyclic AMP response element (CRE) binding protein. Upregulation of COX-2 is mediated by a variety of stimuli including tumor promoters, oncogenes, and growth factors. Stimulation of either protein kinase C (PKC) or Ras signaling enhances mitogen-activated protein kinase (MAPK) activity, which, in turn, activates transcription of cox-2. Celecoxib, the first US FDA approved selective COX-2 inhibitor, initially developed for the treatment of adult rheumatoid arthritis and osteoarthritis, has been reported to reduce the formation of polyps in patients with familial adenomatous polyposis. This COX-2 specific inhibitor also protects against experimentally-induced carcinogenesis, but the underlying molecular mechanisms are poorly understood. The present review covers the signal transduction pathways responsible for regulating COX-2 expression as novel molecular targets of chemopreventive agents with celecoxib as a specific example.

  1. Caveolin interacts with Trk A and p75(NTR) and regulates neurotrophin signaling pathways.

    Science.gov (United States)

    Bilderback, T R; Gazula, V R; Lisanti, M P; Dobrowsky, R T

    1999-01-01

    Neurotrophins signal through Trk tyrosine kinase receptors and the low-affinity neurotrophin receptor p75(NTR). We have shown previously that activation of Trk A tyrosine kinase activity can inhibit p75(NTR)-dependent sphingomyelin hydrolysis, that caveolae are a localized site for p75(NTR) signaling, and that caveolin can directly interact with p75(NTR). The ability of caveolin to also interact with tyrosine kinase receptors and inhibit their activity led us to hypothesize that caveolin expression may modulate interactions between neurotrophin signaling pathways. PC12 cells were transfected with caveolin that was expressed efficiently and targeted to the appropriate membrane domains. Upon exposure to nerve growth factor (NGF), caveolin-PC12 cells were unable to develop extensive neuritic processes. Caveolin expression in PC12 cells was found to diminish the magnitude and duration of Trk A activation in vivo. This inhibition may be due to a direct interaction of caveolin with Trk A, because Trk A co-immunoprecipitated with caveolin from Cav-Trk A-PC12 cells, and a glutathione S-transferase-caveolin fusion protein bound to Trk A and inhibited NGF-induced autophosphorylation in vitro. Furthermore, the in vivo kinetics of the inhibition of Trk A tyrosine kinase activity by caveolin expression correlated with an increased ability of NGF to induce sphingomyelin hydrolysis through p75(NTR). In summary, our results suggest that the interaction of caveolin with neurotrophin receptors may have functional consequences in regulating signaling through p75(NTR) and Trk A in neuronal and glial cell populations.

  2. PARM-1 promotes cardiomyogenic differentiation through regulating the BMP/Smad signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Naohiko [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Takahashi, Tomosaburo, E-mail: ttaka@koto.kpu-m.ac.jp [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Ogata, Takehiro; Adachi, Atsuo; Imoto-Tsubakimoto, Hiroko [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Ueyama, Tomomi, E-mail: toueyama-circ@umin.ac.jp [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Matsubara, Hiroaki [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer PARM-1 expression is induced during cardiomyogenesis. Black-Right-Pointing-Pointer PARM-1 expression precedes Nkx2.5 and Tbx5 during cardiomyogenesis. Black-Right-Pointing-Pointer PARM-1 activates BMP/Smad signaling. Black-Right-Pointing-Pointer PARM-1 enhances cardiac specification, resulting in promoted cardiomyogenesis. -- Abstract: PARM-1, prostatic androgen repressed message-1, is an endoplasmic reticulum (ER) molecule that is involved in ER stress-induced apoptosis in cardiomyocytes. In this study, we assessed whether PARM-1 plays a role in the differentiation of stem cells into cardiomyocytes. While PARM-1 was not expressed in undifferentiated P19CL6 embryonic carcinoma cells, PARM-1 expression was induced during cardiomyogenic differentiation. This expression followed expression of mesodermal markers, and preceded expression of cardiac transcription factors. PARM-1 overexpression did not alter the expression of undifferentiated markers and the proliferative property in undifferentiated P19CL6 cells. Expression of cardiac transcription factors during cardiomyogenesis was markedly enhanced by overexpression of PARM-1, while expression of mesodermal markers was not altered, suggesting that PARM-1 is involved in the differentiation from the mesodermal lineage to cardiomyocytes. Furthermore, overexpression of PARM-1 induced BMP2 mRNA expression in undifferentiated P19CL6 cells and enhanced both BMP2 and BMP4 mRNA expression in the early phase of cardiomyogenesis. PARM-1 overexpression also enhanced phosphorylation of Smads1/5/8. Thus, PARM-1 plays an important role in the cardiomyogenic differentiation of P19CL6 cells through regulating BMP/Smad signaling pathways, demonstrating a novel role of PARM-1 in the cardiomyogenic differentiation of stem cells.

  3. An amphipathic alpha-helix in the prodomain of cocaine and amphetamine regulated transcript peptide precursor serves as its sorting signal to the regulated secretory pathway.

    Directory of Open Access Journals (Sweden)

    Elías H Blanco

    Full Text Available Cocaine and Amphetamine Regulated Transcript (CART peptides are anorexigenic neuropeptides. The L34F mutation in human CART peptide precursor (proCART has been linked to obesity (Yanik et al. Endocrinology 147: 39, 2006. Decrease in CART peptide levels in individuals carrying the L34F mutation was attributed to proCART subcellular missorting. We studied proCART features required to enter the regulated secretory pathway. The subcellular localization and the secretion mode of monomeric EGFP fused to the full-length or truncated forms of human proCART transiently transfected in PC12 cells were analyzed. Our results showed that the N-terminal 1-41 fragment of proCART was necessary and sufficient to sort proCART to the regulated secretory pathway. In silico modeling predicted an alpha-helix structure located between residues 24-37 of proCART. Helical wheel projection of proCART alpha-helix showed an amphipathic configuration. The L34F mutation does not modify the amphipathicity of proCART alpha-helix and consistently proCARTL34F was efficiently sorted to the regulated secretory pathway. However, four additional mutations to proCARTL34F that reduced its alpha-helix amphipathicity resulted in the missorting of the mutated proCART toward the constitutive secretory pathway. These findings show that an amphipathic alpha-helix is a key cis-structure for the proCART sorting mechanism. In addition, our results indicate that the association between L34F mutation and obesity is not explained by proCART missorting.

  4. A Lexical Framework for Semantic Annotation of Positive and Negative Regulation Relations in Biomedical Pathways

    DEFF Research Database (Denmark)

    Zambach, Sine; Lassen, Tine

    presented here, we analyze 6 frequently used verbs denoting the regulation relations regulates, positively regulates and negatively regulates through corpus analysis, and propose a formal representation of the acquired knowledge as domain speci¯c semantic frames. The acquired knowledge patterns can thus...

  5. Brain-derived neurotrophic factor activation of extracellular signal-regulated kinase is autonomous from the dominant extrasynaptic NMDA receptor extracellular signal-regulated kinase shutoff pathway.

    Science.gov (United States)

    Mulholland, P J; Luong, N T; Woodward, J J; Chandler, L J

    2008-01-24

    NMDA receptors bidirectionally modulate extracellular signal-regulated kinase (ERK) through the coupling of synaptic NMDA receptors to an ERK activation pathway that is opposed by a dominant ERK shutoff pathway thought to be coupled to extrasynaptic NMDA receptors. In the present study, synaptic NMDA receptor activation of ERK in rat cortical cultures was partially inhibited by the highly selective NR2B antagonist Ro25-6981 (Ro) and the less selective NR2A antagonist NVP-AAM077 (NVP). When Ro and NVP were added together, inhibition appeared additive and equal to that observed with the NMDA open-channel blocker MK-801. Consistent with a selective coupling of extrasynaptic NMDA receptors to the dominant ERK shutoff pathway, pre-block of synaptic NMDA receptors with MK-801 did not alter the inhibitory effect of bath-applied NMDA on ERK activity. Lastly, in contrast to a complete block of synaptic NMDA receptor activation of ERK by extrasynaptic NMDA receptors, activation of extrasynaptic NMDA receptors had no effect upon ERK activation by brain-derived neurotrophic factor. These results suggest that the synaptic NMDA receptor ERK activation pathway is coupled to both NR2A and NR2B containing receptors, and that the extrasynaptic NMDA receptor ERK inhibitory pathway is not a non-selective global ERK shutoff.

  6. Regulation of aromatics biodegradation by rhl quorum sensing system through induction of catechol meta-cleavage pathway.

    Science.gov (United States)

    Yong, Yang-Chun; Zhong, Jian-Jiang

    2013-05-01

    The mechanism for quorum sensing (QS) regulation on aromatics degradation was investigated. Deletion of rhl QS system resulted in a significant decrease in aromatics biodegradation as well as the activity of catechol 2,3-dioxygenase (C23O, key enzyme for catechol meta-cleavage pathway) in Pseudomonas aeruginosa CGMCC1.860. Interestingly, this repression could be relieved by N-butyryl homoserine lactone (the signaling molecule of rhl QS system) addition. In accordance, the transcription level of nahH (the gene encoding C23O) and nahR (transcriptional activator) also responded to rhl perturbation in a similar way. The results indicated that rhl QS system positively controlled the catechol meta-cleavage pathway, and hence improved aromatics biodegradation. It suggested manipulation of QS system could be a promising strategy to tune the catechol cleavage pathway and to control aromatics biodegradation.

  7. Alpha-2-glycoprotein 1(AZGP1 regulates biological behaviors of LoVo cells by down-regulating mTOR signaling pathway and endogenous fatty acid synthesis.

    Directory of Open Access Journals (Sweden)

    Ligong Chang

    Full Text Available AZGP1 is a multifaceted protein associated with lipid mobilization, a process that is regulated by FASN and other metabolic pathways such as mTOR signaling. The active mTOR signaling pathway has been found to be involved in a variety of tumors. However, it remains unclear whether it is involved in the regulation of AZGP1 and FASN. An AZGP1-expressing plasmid was transfected into a human colorectal cancer cell line (LoVo with a low expression of AZGP1. The expression of AZGP1, FASN, eIF4E, p-mTOR, p-S6,and S6K1 were measured by Western blot analysis, and target genes were detected by RT-PCR. Cell proliferation was studied using the MTT and colony formation assays. The analysis of apoptosis and the cell cycle phase were assessed by flow cytometry. The capacity of cell migration was investigated using the transwell migration assay. We found that the expression of AZGP1 was up-regulated while the expression of FASN, eIF4E, p-mTOR, p-S6, and S6K1 were down-regulated in LoVo cells after AZGP1 was expressed. The proliferation of malignant cells was reduced in AZGP1-overexpression cells, which is consistent with an increased in the G2-arrest and apoptosis rate. Furthermore, the migration of AZGP1-overexpression cells was decreased. The overexpression of AZGP1 suppressed the activation of the mTOR pathway and endogenous FASN-regulated fatty acid synthesis, mitigating the malignant phenotype of LoVo cells. Herein, we provide evidence that AZGP1 may constitute a novel tumor suppressor for LoVo colorectal cancer cells.

  8. Alpha-2-glycoprotein 1(AZGP1) regulates biological behaviors of LoVo cells by down-regulating mTOR signaling pathway and endogenous fatty acid synthesis.

    Science.gov (United States)

    Chang, Ligong; Tian, Xiaoqiang; Lu, Yinghui; Jia, Min; Wu, Peng; Huang, Peilin

    2014-01-01

    AZGP1 is a multifaceted protein associated with lipid mobilization, a process that is regulated by FASN and other metabolic pathways such as mTOR signaling. The active mTOR signaling pathway has been found to be involved in a variety of tumors. However, it remains unclear whether it is involved in the regulation of AZGP1 and FASN. An AZGP1-expressing plasmid was transfected into a human colorectal cancer cell line (LoVo) with a low expression of AZGP1. The expression of AZGP1, FASN, eIF4E, p-mTOR, p-S6,and S6K1 were measured by Western blot analysis, and target genes were detected by RT-PCR. Cell proliferation was studied using the MTT and colony formation assays. The analysis of apoptosis and the cell cycle phase were assessed by flow cytometry. The capacity of cell migration was investigated using the transwell migration assay. We found that the expression of AZGP1 was up-regulated while the expression of FASN, eIF4E, p-mTOR, p-S6, and S6K1 were down-regulated in LoVo cells after AZGP1 was expressed. The proliferation of malignant cells was reduced in AZGP1-overexpression cells, which is consistent with an increased in the G2-arrest and apoptosis rate. Furthermore, the migration of AZGP1-overexpression cells was decreased. The overexpression of AZGP1 suppressed the activation of the mTOR pathway and endogenous FASN-regulated fatty acid synthesis, mitigating the malignant phenotype of LoVo cells. Herein, we provide evidence that AZGP1 may constitute a novel tumor suppressor for LoVo colorectal cancer cells.

  9. The putrescine biosynthesis pathway in Lactococcus lactis is transcriptionally regulated by carbon catabolic repression, mediated by CcpA.

    Science.gov (United States)

    Linares, Daniel M; del Río, Beatriz; Ladero, Victor; Redruello, Begoña; Martín, María Cruz; Fernández, María; Alvarez, Miguel A

    2013-07-01

    Lactococcus lactis is the lactic acid bacterium most widely used by the dairy industry as a starter for the manufacture of fermented products such as cheese and buttermilk. However, some strains produce putrescine from agmatine via the agmatine deiminase (AGDI) pathway. The proteins involved in this pathway, including those necessary for agmatine uptake and conversion into putrescine, are encoded by the aguB, aguD, aguA and aguC genes, which together form an operon. This paper reports the mechanism of regulation of putrescine biosynthesis in L. lactis. It is shown that the aguBDAC operon, which contains a cre site at the promoter of aguB (the first gene of the operon), is transcriptionally regulated by carbon catabolic repression (CCR) mediated by the catabolite control protein CcpA.

  10. Tyrosine pathway regulation is host-mediated in the pea aphid symbiosis during late embryonic and early larval development

    DEFF Research Database (Denmark)

    Rabatel, Andréane; Febvay, Gérard; Gaget, Karen;

    2013-01-01

    embryonic and the early larval stages of the pea aphid, characterizing, for the first time, the transcriptional profiles in these developmental phases. Our analyses allowed us to identify key genes in the phenylalanine, tyrosine and dopamine pathways and we identified ACYPI004243, one of the four genes...... encoding for the aspartate transaminase (E.C. 2.6.1.1), as specifically regulated during development. Indeed, the tyrosine biosynthetic pathway is crucial for the symbiotic metabolism as it is shared between the two partners, all the precursors being produced by B. aphidicola. Our microarray data...... are supported by HPLC amino acid analyses demonstrating an accumulation of tyrosine at the same developmental stages, with an up-regulation of the tyrosine biosynthetic genes. Tyrosine is also essential for the synthesis of cuticular proteins and it is an important precursor for cuticle maturation: together...

  11. Changes in the regulation of the Notch signaling pathway are temporally correlated with regenerative failure in the mouse cochlea

    Directory of Open Access Journals (Sweden)

    Juan Cristobal Maass

    2015-03-01

    Full Text Available Sensorineural hearing loss is most commonly caused by the death of hair cells in the organ of Corti, and once lost, mammalian hair cells do not regenerate. In contrast, other vertebrates such as birds can regenerate hair cells by stimulating division and differentiation of neighboring supporting cells. We currently know little of the genetic networks which become active in supporting cells when hair cells die and that are activated in experimental models of hair cell regeneration.. Several studies have shown that neonatal mammalian cochlear supporting cells are able to trans-differentiate into hair cells when cultured in conditions in which the Notch signaling pathway is blocked. We now show that the ability of cochlear supporting cells to trans-differentiate declines precipitously after birth, such that supporting cells from six-day-old mouse cochlea are entirely unresponsive to a blockade of the Notch pathway. We show that this trend is seen regardless of whether the Notch pathway is blocked with gamma secretase inhibitors, or by antibodies against the Notch1 receptor, suggesting that the action of gamma secretase inhibitors on neonatal supporting cells is likely to be by inhibiting Notch receptor cleavage. The loss of responsiveness to inhibition of the Notch pathway in the first postnatal week is due in part to a down-regulation of Notch receptors and ligands, and we show that this down-regulation persists in the adult animal, even under conditions of noise damage. Our data suggest that the Notch pathway is used to establish the repeating pattern of hair cells and supporting cells in the organ of Corti, but is not required to maintain this cellular mosaic once the production of hair cells and supporting cells is completed. Our results have implications for the proposed used of Notch pathway inhibitors in hearing restoration therapies.

  12. Insulin/IGF-I regulation of necdin and brown adipocyte differentiation via CREB- and FoxO1-associated pathways

    DEFF Research Database (Denmark)

    Cypess, Aaron M; Zhang, Hongbin; Schulz, Tim J

    2011-01-01

    Brown adipose tissue plays an important role in obesity, insulin resistance, and diabetes. We have previously shown that the transition from brown preadipocytes to mature adipocytes is mediated in part by insulin receptor substrate (IRS)-1 and the cell cycle regulator protein necdin. In this study...... is regulated by the phosphoinositide 3 kinase-Akt pathway, increased necdin promoter activity. Based on reporter gene assays using truncations of the necdin promoter and chromatin immunoprecipitation studies, we demonstrated that CREB and FoxO1 are recruited to the necdin promoter, likely interacting...

  13. MAPK Signal Transduction Pathway Regulation: A Novel Mechanism of Rat HSC-T6 Cell Apoptosis Induced by FUZHENGHUAYU Tablet

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2013-01-01

    Full Text Available FUZHENGHUAYU Tablets have been widely used in the treatment of liver fibrosis in China. Here, we investigate the apoptotic effect of FUZHENGHUAYU Tablet in rat liver stellate cell line HSC-T6. HSC-T6 cells were incubated with control serum or drug serum from rats fed with 0.9% NaCl or FUZHENGHUAYU Tablet, respectively. Cells exposed to drug serum showed higher proportions of early and late apoptotic cells than controls. The mRNA levels of collagens I and III, TGF-β1 and α-SMA were reduced by drug serum compared to control serum. Differentially expressed mRNAs and miRNAs were analyzed by microarray and sequencing, respectively. We identified 334 differentially expressed mRNAs and also 60 GOs and two pathways related to the mRNAs. Seventy-five differentially expressed miRNAs were down-regulated by drug serum and 1963 target genes were predicted. 134 GOs up-regulated in drug serum group were linked to miRNA targets, and drug serum also regulated 43 miRNA signal transduction pathways. Protein levels were evaluated by Western blot. Drug serum down-regulated (phospho-SAPK/JNK/(SAPK/JNK and up-regulated phospho-p38/p38 ratios. The study showed that FUZHENGHUAYU Tablet induced apoptosis in rat HSC-T6 cells possibly in part by activating p38 and inhibiting SAPK/JNK.

  14. Redox regulation of genome stability by effects on gene expression, epigenetic pathways and DNA damage/repair

    Directory of Open Access Journals (Sweden)

    Yuliya Mikhed

    2015-08-01

    Full Text Available Reactive oxygen and nitrogen species (e.g. H2O2, nitric oxide confer redox regulation of essential cellular signaling pathways such as cell differentiation, proliferation, migration and apoptosis. In addition, classical regulation of gene expression or activity, including gene transcription to RNA followed by translation to the protein level, by transcription factors (e.g. NF-κB, HIF-1α and mRNA binding proteins (e.g. GAPDH, HuR is subject to redox regulation. This review will give an update of recent discoveries in this field, and specifically highlight the impact of reactive oxygen and nitrogen species on DNA repair systems that contribute to genomic stability. Emphasis will be placed on the emerging role of redox mechanisms regulating epigenetic pathways (e.g. miRNA, DNA methylation and histone modifications. By providing clinical correlations we discuss how oxidative stress can impact on gene regulation/activity and vise versa, how epigenetic processes, other gene regulatory mechanisms and DNA repair can influence the cellular redox state and contribute or prevent development or progression of disease.

  15. Redox regulation of genome stability by effects on gene expression, epigenetic pathways and DNA damage/repair.

    Science.gov (United States)

    Mikhed, Yuliya; Görlach, Agnes; Knaus, Ulla G; Daiber, Andreas

    2015-08-01

    Reactive oxygen and nitrogen species (e.g. H2O2, nitric oxide) confer redox regulation of essential cellular signaling pathways such as cell differentiation, proliferation, migration and apoptosis. In addition, classical regulation of gene expression or activity, including gene transcription to RNA followed by translation to the protein level, by transcription factors (e.g. NF-κB, HIF-1α) and mRNA binding proteins (e.g. GAPDH, HuR) is subject to redox regulation. This review will give an update of recent discoveries in this field, and specifically highlight the impact of reactive oxygen and nitrogen species on DNA repair systems that contribute to genomic stability. Emphasis will be placed on the emerging role of redox mechanisms regulating epigenetic pathways (e.g. miRNA, DNA methylation and histone modifications). By providing clinical correlations we discuss how oxidative stress can impact on gene regulation/activity and vise versa, how epigenetic processes, other gene regulatory mechanisms and DNA repair can influence the cellular redox state and contribute or prevent development or progression of disease.

  16. Ethylene responses in rice roots and coleoptiles are differentially regulated by a carotenoid isomerase-mediated abscisic acid pathway.

    Science.gov (United States)

    Yin, Cui-Cui; Ma, Biao; Collinge, Derek Phillip; Pogson, Barry James; He, Si-Jie; Xiong, Qing; Duan, Kai-Xuan; Chen, Hui; Yang, Chao; Lu, Xiang; Wang, Yi-Qin; Zhang, Wan-Ke; Chu, Cheng-Cai; Sun, Xiao-Hong; Fang, Shuang; Chu, Jin-Fang; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2015-04-01

    Ethylene and abscisic acid (ABA) act synergistically or antagonistically to regulate plant growth and development. ABA is derived from the carotenoid biosynthesis pathway. Here, we analyzed the interplay among ethylene, carotenoid biogenesis, and ABA in rice (Oryza sativa) using the rice ethylene response mutant mhz5, which displays a reduced ethylene response in roots but an enhanced ethylene response in coleoptiles. We found that MHZ5 encodes a carotenoid isomerase and that the mutation in mhz5 blocks carotenoid biosynthesis, reduces ABA accumulation, and promotes ethylene production in etiolated seedlings. ABA can largely rescue the ethylene response of the mhz5 mutant. Ethylene induces MHZ5 expression, the production of neoxanthin, an ABA biosynthesis precursor, and ABA accumulation in roots. MHZ5 overexpression results in enhanced ethylene sensitivity in roots and reduced ethylene sensitivity in coleoptiles. Mutation or overexpression of MHZ5 also alters the expression of ethylene-responsive genes. Genetic studies revealed that the MHZ5-mediated ABA pathway acts downstream of ethylene signaling to inhibit root growth. The MHZ5-mediated ABA pathway likely acts upstream but negatively regulates ethylene signaling to control coleoptile growth. Our study reveals novel interactions among ethylene, carotenogenesis, and ABA and provides insight into improvements in agronomic traits and adaptive growth through the manipulation of these pathways in rice.

  17. The IMD innate immunity pathway of Drosophila influences somatic sex determination via regulation of the Doa locus.

    Science.gov (United States)

    Zhao, Yunpo; Cocco, Claudia; Domenichini, Severine; Samson, Marie-Laure; Rabinow, Leonard

    2015-11-15

    The IMD pathway induces the innate immune response to infection by gram-negative bacteria. We demonstrate strong female-to-male sex transformations in double mutants of the IMD pathway in combination with Doa alleles. Doa encodes a protein kinase playing a central role in somatic sex determination through its regulation of alternative splicing of dsx transcripts. Transcripts encoding two specific Doa isoforms are reduced in Rel null mutant females, supporting our genetic observations. A role for the IMD pathway in somatic sex determination is further supported by the induction of female-to-male sex transformations by Dredd mutations in sensitized genetic backgrounds. In contrast, mutations in either dorsal or Dif, the two other NF-κB paralogues of Drosophila, display no effects on sex determination, demonstrating the specificity of IMD signaling. Our results reveal a novel role for the innate immune IMD signaling pathway in the regulation of somatic sex determination in addition to its role in response to microbial infection, demonstrating its effects on alternative splicing through induction of a crucial protein kinase.

  18. The cross-pathway control system regulates production of the secondary metabolite toxin, sirodesmin PL, in the ascomycete, Leptosphaeria maculans

    Directory of Open Access Journals (Sweden)

    Fox Ellen M

    2011-07-01

    Full Text Available Abstract Background Sirodesmin PL is a secondary metabolite toxin made by the ascomycetous plant pathogen, Leptosphaeria maculans. The sirodesmin biosynthetic genes are clustered in the genome. The key genes are a non-ribosomal peptide synthetase, sirP, and a pathway-specific transcription factor, sirZ. Little is known about regulation of sirodesmin production. Results Genes involved in regulation of sirodesmin PL in L. maculans have been identified. Two hundred random insertional T-DNA mutants were screened with an antibacterial assay for ones producing low levels of sirodesmin PL. Three such mutants were isolated and each transcribed sirZ at very low levels. One of the affected genes had high sequence similarity to Aspergillus fumigatus cpcA, which regulates the cross-pathway control system in response to amino acid availability. This gene was silenced in L. maculans and the resultant mutant characterised. When amino acid starvation was artificially-induced by addition of 3-aminotriazole for 5 h, transcript levels of sirP and sirZ did not change in the wild type. In contrast, levels of sirP and sirZ transcripts increased in the silenced cpcA mutant. After prolonged amino acid starvation the silenced cpcA mutant produced much higher amounts of sirodesmin PL than the wild type. Conclusions Production of sirodesmin PL in L. maculans is regulated by the cross pathway control gene, cpcA, either directly or indirectly via the pathway-specific transcription factor, sirZ.

  19. Differential regulation of BDNF, synaptic plasticity and sprouting in the hippocampal mossy fiber pathway of male and female rats

    OpenAIRE

    SCHARFMAN, HELEN E.; MacLusky, Neil J.

    2013-01-01

    Many studies have described potent effects of BDNF, 17β-estradiol or androgen on hippocampal synapses and their plasticity. Far less information is available about the interactions between 17β-estradiol and BDNF in hippocampus, or interactions between androgen and BDNF in hippocampus. Here we review the regulation of BDNF in the mossy fiber pathway, a critical part of hippocampal circuitry. We discuss the emerging view that 17β-estradiol upregulates mossy fiber BDNF synthesis in the adult fem...

  20. Granulocyte colony-stimulating factor regulates JNK pathway to alleviate damage after cerebral ischemia reperfusion

    Institute of Scientific and Technical Information of China (English)

    LI Ya-guo; LIU Xiao-li; ZHENG Chao-bo

    2013-01-01

    cerebral ischemia reperfusion-damaged cortex and hippocampus was significantly decreased in all G-CSF-treated rats (P <0.05).However,between the long-acting and short-acting G-CSF sets,there were no significant differences found in the activity of P-JNK and P-c-jun in the cortex,hippocampus and striate body (P >0.05).Conclusions Hypodermic injection of 50 μg/kg G-CSF attenuated the damage caused by cerebral ischemia reperfusion in rats,which might be associated with down-regulated activation of the P-JNK and P-c-jun pathway after cerebral ischemia reperfusion.Long-acting G-CSF may be a novel choice for both clinical and basic research in treating cerebral ischemia.

  1. GAIP interacting protein C-terminus regulates autophagy and exosome biogenesis of pancreatic cancer through metabolic pathways.

    Directory of Open Access Journals (Sweden)

    Santanu Bhattacharya

    Full Text Available GAIP interacting protein C terminus (GIPC is known to play an important role in a variety of physiological and disease states. In the present study, we have identified a novel role for GIPC as a master regulator of autophagy and the exocytotic pathways in cancer. We show that depletion of GIPC-induced autophagy in pancreatic cancer cells, as evident from the upregulation of the autophagy marker LC3II. We further report that GIPC regulates cellular trafficking pathways by modulating the secretion, biogenesis, and molecular composition of exosomes. We also identified the involvement of GIPC on metabolic stress pathways regulating autophagy and microvesicular shedding, and observed that GIPC status determines the loading of cellular cargo in the exosome. Furthermore, we have shown the overexpression of the drug resistance gene ABCG2 in exosomes from GIPC-depleted pancreatic cancer cells. We also demonstrated that depletion of GIPC from cancer cells sensitized them to gemcitabine treatment, an avenue that can be explored as a potential therapeutic strategy to overcome drug resistance in cancer.

  2. Fructose-1,6-bisphosphatase is a novel regulator of Wnt/β-Catenin pathway in breast cancer.

    Science.gov (United States)

    Li, Kaichun; Ying, Mingzhen; Feng, Dan; Du, Jie; Chen, Shiyu; Dan, Bing; Wang, Cuihua; Wang, Yajie

    2016-12-01

    Fructose-1,6-bisphosphatase (FBP1), the rate-limiting enzyme in gluconeogenesis, is a tumor suppressor that frequently down-regulated in cancers, especially breast cancer. Here, we provide both supporting and contradicting evidences about the expression pattern and function of FBP1 in breast cancer. Data mining of Oncomine database showed that FBP1 is commonly up-regulated in tumor tissues compared with non-tumor tissues regardless of histological type. Analysis of a large-scale cohort derived from Kaplan-Meier Plotter showed that lower FBP1 expression associated with poor clinical outcome. Genetic silencing of FBP1 reduced aerobic glycolysis and the malignant potential of breast cancer cells. Gene set enrichment analysis (GSEA) of the expression profiles of breast cancer cells (n=59) revealed that cells exhibiting high expression of FBP1 had a lower activity of Wnt/β-Catenin pathway. FBP1 down-regulation enhanced the activity of Wnt/β-Catenin pathway and increased the level of its downstream targets, including c-Myc and MMP7. Collectively, our findings indicate that elevated FBP1 is a critical modulator in breast cancer progression by altering glucose metabolism and the activity of Wnt/β-Catenin pathway.

  3. Chronic up-regulation of the SHH pathway normalizes some developmental effects of trisomy in Ts65Dn mice.

    Science.gov (United States)

    Dutka, Tara; Hallberg, Dorothy; Reeves, Roger H

    2015-02-01

    Down Syndrome (DS) is a highly complex developmental genetic disorder caused by trisomy for human chromosome 21 (Hsa21). All individuals with DS exhibit some degree of brain structural changes and cognitive impairment; mouse models such as Ts65Dn have been instrumental in understanding the underlying mechanisms. Several phenotypes of DS might arise from a reduced response of trisomic cells to the Sonic Hedgehog (SHH) growth factor. If all trisomic cells show a similar reduced response to SHH, then up-regulation of the pathway in trisomic cells might ameliorate multiple DS phenotypes. We crossed Ptch1tm1Mps/+ mice, in which the canonical SHH pathway is expected to be up-regulated in every SHH-responsive cell due to the loss of function of one allele of the pathway suppressor, Ptch1, to the Ts65Dn DS model and assessed the progeny for possible rescue of multiple DS-related phenotypes. Down-regulation of Ptch produced several previously unreported effects on development by itself, complicating interpretation of some phenotypes, and a number of structural or behavioral effects of trisomy were not compensated by SHH signaling. However, a deficit in a nest-building task was partially restored in Ts;Ptch+/- mice, as were the structural anomalies of the cerebellum seen in Ts65Dn mice. These results extend the body of evidence indicating that reduced response to SHH in trisomic cells and tissues contributes to various aspects of the trisomic phenotype.

  4. Role of the ANKMY2-FKBP38 axis in regulation of the Sonic hedgehog (Shh) signaling pathway.

    Science.gov (United States)

    Saita, Shotaro; Shirane, Michiko; Ishitani, Tohru; Shimizu, Nobuyuki; Nakayama, Keiichi I

    2014-09-12

    Sonic hedgehog (Shh) is a secreted morphogen that controls the patterning and growth of various tissues in the developing vertebrate embryo, including the central nervous system. Ablation of the FK506-binding protein 38 (FKBP38) gene results in activation of the Shh signaling pathway in mouse embryos, but the molecular mechanism by which FKBP38 suppresses Shh signaling has remained unclear. With the use of a proteomics approach, we have now identified ANKMY2, a protein with three ankyrin repeats and a MYND (myeloid, Nervy, and DEAF-1)-type Zn(2+) finger domain, as a molecule that interacts with FKBP38. Co-immunoprecipitation analysis confirmed that endogenous FKBP38 and ANKMY2 interact in the mouse brain. Depletion or overexpression of ANKMY2 resulted in down- and up-regulation of Shh signaling, respectively, in mouse embryonic fibroblasts. Furthermore, combined depletion of both FKBP38 and ANKMY2 attenuated Shh signaling in these cells, suggesting that ANKMY2 acts downstream of FKBP38 to activate the Shh signaling pathway. Targeting of the zebrafish ortholog of mouse Ankmy2 (ankmy2a) in fish embryos with an antisense morpholino oligonucleotide conferred a phenotype reflecting loss of function of the Shh pathway, suggesting that the regulation of Shh signaling by ANKMY2 is conserved between mammals and fish. Our findings thus indicate that the FKBP38-ANKMY2 axis plays a key role in regulation of Shh signaling in vivo.

  5. Two distinct signaling pathways regulate peroxynitrite-induced apoptosis in PC12 cells.

    Science.gov (United States)

    Shacka, J J; Sahawneh, M A; Gonzalez, J D; Ye, Y-Z; D'Alessandro, T L; Estévez, A G

    2006-09-01

    The mechanisms of peroxynitrite-induced apoptosis are not fully understood. We report here that peroxynitrite-induced apoptosis of PC12 cells requires the simultaneous activation of p38 and JNK MAP kinase, which in turn activates the intrinsic apoptotic pathway, as evidenced by Bax translocation to the mitochondria, cytochrome c release to the cytoplasm and activation of caspases, leading to cell death. Peroxynitrite induces inactivation of the Akt pathway. Furthermore, overexpression of constitutively active Akt inhibits both peroxynitrite-induced Bax translocation and cell death. Peroxynitrite-induced death was prevented by overexpression of Bcl-2 and by cyclosporin A, implicating the involvement of the intrinsic apoptotic pathway. Selective inhibition of mixed lineage kinase (MLK), p38 or JNK does not attenuate the decrease in Akt phosphorylation showing that inactivation of the Akt pathway occurs independently of the MLK/MAPK pathway. Together, these results reveal that peroxynitrite-induced activation of the intrinsic apoptotic pathway involves interactions with the MLK/MAPK and Akt signaling pathways.

  6. Pathway analysis of Pichia pastoris to elucidate methanol metabolism and its regulation for production of recombinant proteins.

    Science.gov (United States)

    Unrean, Pornkamol

    2014-01-01

    This research rationally analyzes metabolic pathways of Pichia pastoris to study the metabolic flux responses of this yeast under methanol metabolism. A metabolic model of P. pastoris was constructed and analyzed by elementary mode analysis (EMA). EMA was used to comprehensively identify the cell's metabolic flux profiles and its underlying regulation mechanisms for the production of recombinant proteins from methanol. Change in phenotypes and flux profiles during methanol adaptation with varying feed mixture of glycerol and methanol was examined. EMA identified increasing and decreasing fluxes during the glycerol-methanol metabolic shift, which well agreed with experimental observations supporting the validity of the metabolic network model. Analysis of all the identified pathways also led to the determination of the metabolic capacities as well as the optimum metabolic pathways for recombinant protein synthesis during methanol induction. The network sensitivity analysis revealed that the production of proteins can be improved by manipulating the flux ratios at the pyruvate branch point. In addition, EMA suggested that protein synthesis is optimum under hypoxic culture conditions. The metabolic modeling and analysis presented in this study could potentially form a valuable knowledge base for future research on rational design and optimization of P. pastoris by determining target genes, pathways, and culture conditions for enhanced recombinant protein synthesis. The metabolic pathway analysis is also of considerable value for production of therapeutic proteins by P. pastoris in biopharmaceutical applications.

  7. Gene expression analysis of canonical Wnt pathway transcriptional regulators during early morphogenesis of the facial region in the mouse embryo.

    Science.gov (United States)

    Vendrell, Victor; Summerhurst, Kristen; Sharpe, James; Davidson, Duncan; Murphy, Paula

    2009-06-01

    Structures and features of the face, throat and neck are formed from a series of branchial arches that grow out along the ventrolateral aspect of the embryonic head. Multiple signalling pathways have been implicated in patterning interactions that lead to species-specific growth and differentiation within the branchial region that sculpt these features. A direct role for Wnt signalling in particular has been shown. The spatial and temporal distribution of Wnt pathway components contributes to the operation of the signalling system. We present the precise distribution of gene expression of canonical Wnt pathway transcriptional regulators, Tcf1, Lef1, Tcf3, Tcf4 and beta-catenin between embryonic day (E) 9.5 and 11.5. In situ hybridization combined with Optical Projection Tomography was used to record and compare distribution of transcripts in 3D within the developing branchial arches. This shows widespread yet very specific expression of the gene set indicating that all genes contribute to proper patterning of the region. Tcf1 and Lef1 are more prominent in rostral arches, particularly at later ages, and Tcf3 and Tcf4 are in general expressed more deeply (medial/endodermal aspect) in the arches than Tcf1 and Lef1. Comparison with Wnt canonical pathway readout patterns shows that the relationship between the expression of individual transcription factors and activation of the pathway is not simple, indicating complexity and flexibility in the signalling system.

  8. Mechanism of Notch Pathway Activation and Its Role in the Regulation of Olfactory Plasticity in Drosophila melanogaster.

    Science.gov (United States)

    Kidd, Simon; Lieber, Toby

    2016-01-01

    The neural plasticity of sensory systems is being increasingly recognized as playing a role in learning and memory. We have previously shown that Notch, part of an evolutionarily conserved intercellular signaling pathway, is required in adult Drosophila melanogaster olfactory receptor neurons (ORNs) for the structural and functional plasticity of olfactory glomeruli that is induced by chronic odor exposure. In this paper we address how long-term exposure to odor activates Notch and how Notch in conjunction with chronic odor mediates olfactory plasticity. We show that upon chronic odor exposure a non-canonical Notch pathway mediates an increase in the volume of glomeruli by a mechanism that is autonomous to ORNs. In addition to activating a pathway that is autonomous to ORNs, chronic odor exposure also activates the Notch ligand Delta in second order projection neurons (PNs), but this does not appear to require acetylcholine receptor activation in PNs. Delta on PNs then feeds back to activate canonical Notch signaling in ORNs, which restricts the extent of the odor induced increase in glomerular volume. Surprisingly, even though the pathway that mediates the increase in glomerular volume is autonomous to ORNs, nonproductive transsynaptic Delta/Notch interactions that do not activate the canonical pathway can block the increase in volume. In conjunction with chronic odor, the canonical Notch pathway also enhances cholinergic activation of PNs. We present evidence suggesting that this is due to increased acetylcholine release from ORNs. In regulating physiological plasticity, Notch functions solely by the canonical pathway, suggesting that there is no direct connection between morphological and physiological plasticity.

  9. Mechanism of Notch Pathway Activation and Its Role in the Regulation of Olfactory Plasticity in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Simon Kidd

    Full Text Available The neural plasticity of sensory systems is being increasingly recognized as playing a role in learning and memory. We have previously shown that Notch, part of an evolutionarily conserved intercellular signaling pathway, is required in adult Drosophila melanogaster olfactory receptor neurons (ORNs for the structural and functional plasticity of olfactory glomeruli that is induced by chronic odor exposure. In this paper we address how long-term exposure to odor activates Notch and how Notch in conjunction with chronic odor mediates olfactory plasticity. We show that upon chronic odor exposure a non-canonical Notch pathway mediates an increase in the volume of glomeruli by a mechanism that is autonomous to ORNs. In addition to activating a pathway that is autonomous to ORNs, chronic odor exposure also activates the Notch ligand Delta in second order projection neurons (PNs, but this does not appear to require acetylcholine receptor activation in PNs. Delta on PNs then feeds back to activate canonical Notch signaling in ORNs, which restricts the extent of the odor induced increase in glomerular volume. Surprisingly, even though the pathway that mediates the increase in glomerular volume is autonomous to ORNs, nonproductive transsynaptic Delta/Notch interactions that do not activate the canonical pathway can block the increase in volume. In conjunction with chronic odor, the canonical Notch pathway also enhances cholinergic activation of PNs. We present evidence suggesting that this is due to increased acetylcholine release from ORNs. In regulating physiological plasticity, Notch functions solely by the canonical pathway, suggesting that there is no direct connection between morphological and physiological plasticity.

  10. DMPD: Regulation of endogenous apolipoprotein E secretion by macrophages. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18388328 Regulation of endogenous apolipoprotein E secretion by macrophages. Kockx M, Jessup...328 Title Regulation of endogenous apolipoprotein E secretion by macrophages. Authors Kockx M, Jessup

  11. DMPD: Toll-like receptors regulation of viral infection and disease. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18280610 Toll-like receptors regulation of viral infection and disease. Thompson JM...how Toll-like receptors regulation of viral infection and disease. PubmedID 18280610 Title Toll-like recepto...rs regulation of viral infection and disease. Authors Thompson JM, Iwasaki A. Pub

  12. DMPD: The Lps locus: genetic regulation of host responses to bacteriallipopolysaccharide. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 10669111 The Lps locus: genetic regulation of host responses to bacteriallipopolysa...w The Lps locus: genetic regulation of host responses to bacteriallipopolysaccharide. PubmedID 10669111 Titl...e The Lps locus: genetic regulation of host responses to bacteriallipopolysacchar

  13. DMPD: The SAP family of adaptors in immune regulation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15541655 The SAP family of adaptors in immune regulation. Latour S, Veillette A. Se...min Immunol. 2004 Dec;16(6):409-19. (.png) (.svg) (.html) (.csml) Show The SAP family of adaptors in immune ...regulation. PubmedID 15541655 Title The SAP family of adaptors in immune regulation. Authors Latour S, Veill

  14. DMPD: Regulation of cytokine signaling by SOCS family molecules. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 14644140 Regulation of cytokine signaling by SOCS family molecules. Fujimoto M, Nak...a T. Trends Immunol. 2003 Dec;24(12):659-66. (.png) (.svg) (.html) (.csml) Show Regulation of cytokine signaling by SOCS family... molecules. PubmedID 14644140 Title Regulation of cytokine signaling by SOCS family molec

  15. DMPD: Negative regulation of cytoplasmic RNA-mediated antiviral signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18703349 Negative regulation of cytoplasmic RNA-mediated antiviral signaling. Komur...Show Negative regulation of cytoplasmic RNA-mediated antiviral signaling. PubmedID 18703349 Title Negative r...egulation of cytoplasmic RNA-mediated antiviral signaling. Authors Komuro A, Bamm

  16. DMPD: Innate immune responses: crosstalk of signaling and regulation of genetranscription. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16753195 Innate immune responses: crosstalk of signaling and regulation of genetran...l) (.csml) Show Innate immune responses: crosstalk of signaling and regulation of genetranscription. PubmedI...D 16753195 Title Innate immune responses: crosstalk of signaling and regulation o

  17. DMPD: Iron regulation of hepatic macrophage TNFalpha expression. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 11841920 Iron regulation of hepatic macrophage TNFalpha expression. Tsukamoto H. Fr...ee Radic Biol Med. 2002 Feb 15;32(4):309-13. (.png) (.svg) (.html) (.csml) Show Iron regulation of hepatic m...acrophage TNFalpha expression. PubmedID 11841920 Title Iron regulation of hepatic macrophage TNFalpha expres

  18. DMPD: Receptor tyrosine kinases and the regulation of macrophage activation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 14726496 Receptor tyrosine kinases and the regulation of macrophage activation. Cor...(.csml) Show Receptor tyrosine kinases and the regulation of macrophage activation. PubmedID 14726496 Title ...Receptor tyrosine kinases and the regulation of macrophage activation. Authors Co

  19. Opposing activities of the Ras and Hippo pathways converge on regulation of YAP protein turnover

    DEFF Research Database (Denmark)

    Hong, Xin; Nguyen, Thanh Hung; Chen, Qingfeng;

    2014-01-01

    Cancer genomes accumulate numerous genetic and epigenetic modifications. Yet, human cellular transformation can be accomplished by a few genetically defined elements. These elements activate key pathways required to support replicative immortality and anchorage independent growth, a predictor of ...

  20. The Cell Death Pathway Regulates Synapse Elimination through Cleavage of Gelsolin in Caenorhabditis elegans Neurons

    Directory of Open Access Journals (Sweden)

    Lingfeng Meng

    2015-06-01

    Full Text Available Synapse elimination occurs in development, plasticity, and disease. Although the importance of synapse elimination has been documented in many studies, the molecular mechanisms underlying this process are unclear. Here, using the development of C. elegans RME neurons as a model, we have uncovered a function for the apoptosis pathway in synapse elimination. We find that the conserved apoptotic cell death (CED pathway and axonal mitochondria are required for the elimination of transiently formed clusters of presynaptic components in RME neurons. This function of the CED pathway involves the activation of the actin-filament-severing protein, GSNL-1. Furthermore, we show that caspase CED-3 cleaves GSNL-1 at a conserved C-terminal region and that the cleaved active form of GSNL-1 promotes its actin-severing ability. Our data suggest that activation of the CED pathway contributes to selective elimination of synapses through disassembly of the actin filament network.

  1. Phytochrome and retrograde signalling pathways coverage to antogonistically regulate a light-induced transcription network

    Science.gov (United States)

    Plastid-to-nucleus retrograde signals emitted by dysfunctional chloroplasts impact photomorphogenic development, but the molecular link between retrograde and photosensory-receptor signaling has remained undefined. Here, we show that the phytochrome (phy) and retrograde signaling pathways converge a...

  2. Regulation of polarized extension and planar cell polarity in the cochlea by the vertebrate PCP pathway.

    Science.gov (United States)

    Wang, Jianbo; Mark, Sharayne; Zhang, Xiaohui; Qian, Dong; Yoo, Seung-Jong; Radde-Gallwitz, Kristen; Zhang, Yanping; Lin, Xi; Collazo, Andres; Wynshaw-Boris, Anthony; Chen, Ping

    2005-09-01

    The mammalian auditory sensory organ, the organ of Corti, consists of sensory hair cells with uniformly oriented stereocilia on the apical surfaces and has a distinct planar cell polarity (PCP) parallel to the sensory epithelium. It is not certain how this polarity is achieved during differentiation. Here we show that the organ of Corti is formed from a thicker and shorter postmitotic primordium through unidirectional extension, characteristic of cellular intercalation known as convergent extension. Mutations in the PCP pathway interfere with this extension, resulting a shorter and wider cochlea as well as misorientation of stereocilia. Furthermore, parallel to the homologous pathway in Drosophila melanogaster, a mammalian PCP component Dishevelled2 shows PCP-dependent polarized subcellular localization across the organ of Corti. Taken together, these data suggest that there is a conserved molecular mechanism for PCP pathways in invertebrates and vertebrates and indicate that the mammalian PCP pathway might directly couple cellular intercalations to PCP establishment in the cochlea.

  3. Neuronal development in Caenorhabditis elegans is regulated by inhibition of an MLK MAP kinase pathway.

    Science.gov (United States)

    Baker, Scott T; Turgeon, Shane M; Tulgren, Erik D; Wigant, Jeanne; Rahimi, Omeed; Opperman, Karla J; Grill, Brock

    2015-01-01

    We show that loss-of-function mutations in kinases of the MLK-1 pathway (mlk-1, mek-1, and kgb-1/jnk) function cell-autonomously in neurons to suppress defects in synapse formation and axon termination caused by rpm-1 loss of function. Our genetic analysis also suggests that the phosphatase PPM-1, like RPM-1, is a potential inhibitor of kinases in the MLK-1 pathway.

  4. 植物MEP途径的代谢调控机制%Multiple Regulation Mechanisms of MEP Pathway in Plant

    Institute of Scientific and Technical Information of China (English)

    张松涛; 陈红丽; 崔红; 杨惠娟; 刘国顺

    2012-01-01

    Terpenoids metabolism is one of the most important pathways of secondary metabolism in plant. The regulatory mechanisms that modulate this metabolic route will determine plant growth and development, resistance, quality and other aspects. The terpene precursors are synthesized by the 2-C-Methyl-D-E-rythritol-4-Phosphate (MEP) pathway in plant plastids. Recent studies have shown that, many genes involved in MEP pathway are not only regulated by multiple genes encoding and the transcript level,but also by post-transcriptional mechanism. Post-transcriptional regulation is a novel regulation mechanism described recently for this way and the mechanism is not clear. We review here various regulatory mechanisms of MEP pathway in plant, especially the mechanism and signal molecular that may be involved in post-transcriptional regulation,which may provide the theory basis for the research of regulation in this pathway.%萜类代谢途径是植物中最重要的次生代谢途径之一,对其有效的调控决定着植物的生长发育、抗性及品质等各个方面.植物中类萜合成的前体物在质体中是由2-C-甲基-D-赤藓糖醇-4-磷酸(2-C-Methyl-D-Erythritol-4-Phosphate,MEP)途径合成的,MEP途径中的许多基因除了受到多基因编码和转录水平的调节外,还受到转录后调节机制的调节,而转录后调节是一种新发现的调节方式,其机制还不是很清楚.该文重点对近年来国内外有关植物MEP途径的多种调节方式,尤其是转录后调节的调节机制及其可能参与的信号分子方面的研究进展进行综述,为植物的MEP途径的代谢调控提供参考.

  5. miR-339-5p regulates the p53 tumor-suppressor pathway by targeting MDM2

    DEFF Research Database (Denmark)

    Jansson, M D; Djodji Damas, Nkerorema; Lees, M

    2014-01-01

    MicroRNAs (miRNAs) regulate many key cancer-relevant pathways and may themselves possess oncogenic or tumor-suppressor functions. Consequently, miRNA dysregulation has been shown to be a prominent feature in many human cancers. The p53 tumor suppressor acts as a negative regulator of cell...... proliferation in response to stress and represents the most commonly lost and mutated gene in human cancers. The function of p53 is inhibited by the MDM2 oncoprotein. Using a high-throughput screening approach, we identified miR-339-5p as a regulator of the p53 pathway. We demonstrate that this regulation...... inhibition of miR-339-5p function perturbs the p53 response in cancer cells, allowing an increased proliferation rate. In addition, miR-339-5p expression is downregulated in tumors harboring wild-type TP53, suggesting that reduction of miR-339-5p level helps to suppress the p53 response in p53-competent...

  6. Target regulation of PI3K/Akt/mTOR pathway by cannabidiol in treatment of experimental multiple sclerosis.

    Science.gov (United States)

    Giacoppo, Sabrina; Pollastro, Federica; Grassi, Gianpaolo; Bramanti, Placido; Mazzon, Emanuela

    2017-01-01

    This study was aimed to investigate whether treatment with purified cannabidiol (CBD) may counteract the development of experimental multiple sclerosis (MS), by targeting the PI3K/Akt/mTOR pathway. Although the PI3K/Akt/mTOR pathway was found to be activated by cannabinoids in several immune and non-immune cells, currently, there is no data about the effects of CBD in the PI3K/Akt/mTOR activity in MS. Experimental Autoimmune Encephalomyelitis (EAE), the most common model of MS, was induced in C57BL/6 mice by immunization with myelin oligodendroglial glycoprotein peptide (MOG)35-55. After EAE onset, which occurs approximately 14days after disease induction, mice were daily intraperitoneally treated with CBD (10mg/kg mouse) and observed for clinical signs of EAE. At 28days from EAE-induction, mice were euthanized and spinal cord tissues were sampled to perform immunohistochemical evaluations and western blot analysis. Our results showed a clear downregulation of the PI3K/Akt/mTOR pathway following EAE induction. CBD treatment was able to restore it, increasing significantly the phosphorylation of PI3K, Akt and mTOR. Also, an increased level of BNDF in CBD-treated mice seems to be involved in the activation of PI3K/Akt/mTOR pathway. In addition, our data demonstrated that therapeutic efficacy of CBD treatment is due to reduction of pro-inflammatory cytokines, like IFN-γ and IL-17 together with an up-regulation of PPARγ. Finally, CBD was found to promote neuronal survival by inhibiting JNK and p38 MAP kinases. These results provide an interesting discovery about the regulation of the PI3K/Akt/mTOR pathway by cannabidiol administration, that could be a new potential therapeutic target for MS management.

  7. Late activation of the 9-oxylipin pathway during arbuscular mycorrhiza formation in tomato and its regulation by jasmonate signalling

    Science.gov (United States)

    León-Morcillo, Rafael Jorge; Ángel, José; Martín-Rodríguez; Vierheilig, Horst; Ocampo, Juan Antonio; García-Garrido, José Manuel

    2012-01-01

    The establishment of an arbuscular mycorrhizal (AM) symbiotic interaction is a successful strategy for the promotion of substantial plant growth, development, and fitness. Numerous studies have supported the hypothesis that plant hormones play an important role in the establishment of functional AM symbiosis. Particular attention has been devoted to jasmonic acid (JA) and its derivates, which are believed to play a major role in AM symbiosis. Jasmonates belong to a diverse class of lipid metabolites known as oxylipins that include other biologically active molecules. Recent transcriptional analyses revealed up-regulation of the oxylipin pathway during AM symbiosis in mycorrhizal tomato roots and indicate a key regulatory role for oxylipins during AM symbiosis in tomato, particularly those derived from the action of 9-lipoxygenases (9-LOXs). Continuing with the tomato as a model, the spatial and temporal expression pattern of genes involved in the 9-LOX pathway during the different stages of AM formation in tomato was analysed. The effects of JA signalling pathway changes on AM fungal colonization were assessed and correlated with the modifications in the transcriptional profiles of 9-LOX genes. The up-regulation of the 9-LOX oxylipin pathway in mycorrhizal wild-type roots seems to depend on a particular degree of AM fungal colonization and is restricted to the colonized part of the roots, suggesting that these genes could play a role in controlling fungal spread in roots. In addition, the results suggest that this strategy of the plant to control AM fungi development within the roots is at least partly dependent on JA pathway activation. PMID:22442425

  8. Regulation of skeletal muscle energy/nutrient-sensing pathways during metabolic adaptation to fasting in healthy humans.

    Science.gov (United States)

    Wijngaarden, Marjolein A; Bakker, Leontine E H; van der Zon, Gerard C; 't Hoen, Peter A C; van Dijk, Ko Willems; Jazet, Ingrid M; Pijl, Hanno; Guigas, Bruno

    2014-11-15

    During fasting, rapid metabolic adaptations are required to maintain energy homeostasis. This occurs by a coordinated regulation of energy/nutrient-sensing pathways leading to transcriptional activation and repression of specific sets of genes. The aim of the study was to investigate how short-term fasting affects whole body energy homeostasis and skeletal muscle energy/nutrient-sensing pathways and transcriptome in humans. For this purpose, 12 young healthy men were studied during a 24-h fast. Whole body glucose/lipid oxidation rates were determined by indirect calorimetry, and blood and skeletal muscle biopsies were collected and analyzed at baseline and after 10 and 24 h of fasting. As expected, fasting induced a time-dependent decrease in plasma insulin and leptin levels, whereas levels of ketone bodies and free fatty acids increased. This was associated with a metabolic shift from glucose toward lipid oxidation. At the molecular level, activation of the protein kinase B (PKB/Akt) and mammalian target of rapamycin pathways was time-dependently reduced in skeletal muscle during fasting, whereas the AMP-activated protein kinase activity remained unaffected. Furthermore, we report some changes in the phosphorylation and/or content of forkhead protein 1, sirtuin 1, and class IIa histone deacetylase 4, suggesting that these pathways might be involved in the transcriptional adaptation to fasting. Finally, transcriptome profiling identified genes that were significantly regulated by fasting in skeletal muscle at both early and late time points. Collectively, our study provides a comprehensive map of the main energy/nutrient-sensing pathways and transcriptomic changes during short-term adaptation to fasting in human skeletal muscle.

  9. Rapamycin (Sirolimus) alters mechanistic target of rapamycin pathway regulation and microRNA expression in mouse meiotic spermatocytes.

    Science.gov (United States)

    Mukherjee, A; Koli, S; Reddy, K V R

    2015-09-01

    Mechanistic target of rapamycin (mTOR) is a signal transduction pathway that modulates translation initiation in several animals including mammals. Rapamaycin, an allosteric inhibitor of mTOR pathway, is often used as an immunosuppressive drug following kidney transplantation and causes gonadal dysfunction and defects in spermatogenesis. The molecular mechanism behind rapamycin-mediated testicular dysfunction is not known. We have therefore explored the contribution of rapamycin in mTOR regulation and microRNA (miRNA) expression in mouse spermatocytes, the intermediate stage of spermatogenesis, where meiosis takes place. In the present study, we optimized the isolation of highly pure and viable spermatocytes by flow sorting, treated them with rapamycin, and investigated the expression of mTOR and downstream effector molecules. Western blot and immunocytochemical analysis confirm that rapamycin treatment suppresses mTOR and phopsphorylated P70S6 kinase activities in spermatocytes, but not that of phosphorylated 4E-binding protein 1. Also, rapamycin treatment modulates the expression of several spermatocyte-specific miRNAs. To complement these finding an in vivo study was also performed. In silico prediction of target genes of these miRNAs and their functional pathway analysis revealed that, several of them are involved in crucial biological process, cellular process and catalytic activities. miRNA-transcription factor (TF) network analysis enlisted different TFs propelling the transcription machineries of these miRNAs. In silico prediction followed by quatitative real-time PCR revealed two of these TFs namely, PU.1 and CCCTC binding factor (CTCF) are down and upregulated, respectively, which may be the reason of the altered expression of miRNAs following rapamycin treatment. In conclusion, for the first time, the present study provides insight into how rapamycin regulates mTOR pathway and spermatocyte-specific miRNA expression which in turn, regulate expression of

  10. Ganoderma atrum polysaccharide evokes antitumor activity via cAMP-PKA mediated apoptotic pathway and down-regulation of Ca(2+)/PKC signal pathway.

    Science.gov (United States)

    Zhang, Shenshen; Nie, Shaoping; Huang, Danfei; Huang, Jianqin; Feng, Yanling; Xie, Mingyong

    2014-06-01

    Ganoderma atrum polysaccharide (PSG-1) has been commonly suggested as a candidate for prevention and therapy of cancer. We investigated the antitumor effect and the underlying molecular mechanisms of PSG-1. The results showed that PSG-1 inhibited tumor growth and resulted in tumor cell apoptosis in vivo. Here, the data revealed that PSG-1 caused a markedly increase in cAMP and PKA activities, rather than cGMP and PKC. Moreover, the treatment of PSG-1 induced a dramatic increase in the protein level of PKA. In contrast, the expression of PKC and intracellular [Ca(2+)]i were inhibited. Our study also revealed that treatment with PSG-1 increased the spleen and thymus weights, lymphocyte proliferation and macrophage phagocytic activity in tumor-bearing mice. Taken together, we conclude that PSG-1 could inhibit the tumor growth, possibly in part by enhancing the induction of apoptosis through cAMP-PKA signaling pathway and down-regulation of Ca(2+)/PKC signal pathway, activating host immune function in S180-bearing mice.

  11. SREBP-1c, regulated by the insulin and AMPK signaling pathways, plays a role in nonalcoholic fatty liver disease.

    Science.gov (United States)

    Kohjima, Motoyuki; Higuchi, Nobito; Kato, Masaki; Kotoh, Kazuhiro; Yoshimoto, Tsuyoshi; Fujino, Tatsuya; Yada, Masayoshi; Yada, Ryoko; Harada, Naohiko; Enjoji, Munechika; Takayanagi, Ryoichi; Nakamuta, Makoto

    2008-04-01

    Nonalcoholic fatty liver disease (NAFLD) is a common liver disease whose prevalence has increased markedly. We reported previously that fatty acid synthesis was enhanced in NAFLD with the accumulation of fatty acids. To clarify the disorder, we evaluated the expression of genes regulating fatty acid synthesis by real-time PCR using samples from NAFLD (n=22) and normal liver (control; n=10). A major regulator of fatty acids synthesis is sterol regulatory element-binding protein-1c (SREBP-1c). Its expression was significantly higher in NAFLD, nearly 5-fold greater than the controls. SREBP-1c is positively regulated by insulin signaling pathways, including insulin receptor substrate (IRS)-1 and -2. In NAFLD, IRS-1 expression was enhanced and correlated positively with SREBP-1c expression. In contrast, IRS-2 expression decreased by 50% and was not correlated with SREBP-1c. Forkhead box protein A2 (Foxa2) is a positive regulator of fatty acid oxidation and is itself negatively regulated by IRSs. Foxa2 expression increased in NAFLD and showed a negative correlation with IRS-2, but not with IRS-1, expression. It is known that SREBP-1c is negatively regulated by AMP-activated protein kinase (AMPK) but expression levels of AMPK in NAFLD were almost equal to those of the controls. These data indicate that, in NAFLD, insulin signaling via IRS-1 causes the up-regulation of SREBP1-c, leading to the increased synthesis of fatty acids by the hepatocytes; negative feedback regulation via AMPK does not occur and the activation of Foxa2, following a decrease of IRS-2, up-regulates fatty acid oxidation.

  12. bHLH142 regulates various metabolic pathway-related genes to affect pollen development and anther dehiscence in rice

    Science.gov (United States)

    Ranjan, Rajeev; Khurana, Reema; Malik, Naveen; Badoni, Saurabh; Parida, Swarup K.; Kapoor, Sanjay; Tyagi, Akhilesh K.

    2017-01-01

    Apposite development of anther and its dehiscence are important for the reproductive success of the flowering plants. Recently, bHLH142, a bHLH transcription factor encoding gene of rice has been found to show anther-specific expression and mutant analyses suggest its functions in regulating tapetum differentiation and degeneration during anther development. However, our study on protein level expression and gain-of-function phenotype revealed novel aspects of its regulation and function during anther development. Temporally dissimilar pattern of bHLH142 transcript and polypeptide accumulation suggested regulation of its expression beyond transcriptional level. Overexpression of bHLH142 in transgenic rice resulted in indehiscent anthers and aborted pollen grains. Defects in septum and stomium rupture caused anther indehiscence while pollen abortion phenotype attributed to abnormal degeneration of the tapetum. Furthermore, RNA-Seq-based transcriptome analysis of tetrad and mature pollen stage anthers of wild type and bHLH142OEplants suggested that it might regulate carbohydrate and lipid metabolism, cell wall modification, reactive oxygen species (ROS) homeostasis and cell death-related genes during rice anther development. Thus, bHLH142 is an anther-specific gene whose expression is regulated at transcriptional and post-transcriptional/translational levels. It plays a role in pollen maturation and anther dehiscence by regulating expression of various metabolic pathways-related genes. PMID:28262713

  13. Mammalian target of rapamycin complex 2 signaling pathway regulates transient receptor potential cation channel 6 in podocytes.

    Directory of Open Access Journals (Sweden)

    Fangrui Ding

    Full Text Available Transient receptor potential cation channel 6 (TRPC6 is a nonselective cation channel, and abnormal expression and gain of function of TRPC6 are involved in the pathogenesis of hereditary and nonhereditary forms of renal disease. Although the molecular mechanisms underlying these diseases remain poorly understood, recent investigations revealed that many signaling pathways are involved in regulating TRPC6. We aimed to examine the effect of the mammalian target of rapamycin (mTOR complex (mTOR complex 1 [mTORC1] or mTOR complex 2 [mTORC2] signaling pathways on TRPC6 in podocytes, which are highly terminally differentiated renal epithelial cells that are critically required for the maintenance of the glomerular filtration barrier. We applied both pharmacological inhibitors of mTOR and specific siRNAs against mTOR components to explore which mTOR signaling pathway is involved in the regulation of TRPC6 in podocytes. The podocytes were exposed to rapamycin, an inhibitor of mTORC1, and ku0063794, a dual inhibitor of mTORC1 and mTORC2. In addition, specific siRNA-mediated knockdown of the mTORC1 component raptor and the mTORC2 component rictor was employed. The TRPC6 mRNA and protein expression levels were examined via real-time quantitative PCR and Western blot, respectively. Additionally, fluorescence calcium imaging was performed to evaluate the function of TRPC6 in podocytes. Rapamycin displayed no effect on the TRPC6 mRNA or protein expression levels or TRPC6-dependent calcium influx in podocytes. However, ku0063794 down-regulated the TRPC6 mRNA and protein levels and suppressed TRPC6-dependent calcium influx in podocytes. Furthermore, knockdown of raptor did not affect TRPC6 expression or function, whereas rictor knockdown suppressed TRPC6 protein expression and TRPC6-dependent calcium influx in podocytes. These findings indicate that the mTORC2 signaling pathway regulates TRPC6 in podocytes but that the mTORC1 signaling pathway does not appear

  14. Characterization of the Arabidopsis clb6 mutant illustrates the importance of posttranscriptional regulation of the methyl-D-erythritol 4-phosphate pathway.

    Science.gov (United States)

    Guevara-García, Arturo; San Román, Carolina; Arroyo, Analilia; Cortés, María Elena; de la Luz Gutiérrez-Nava, María; León, Patricia

    2005-02-01

    The biosynthesis of isopentenyl diphosphate and dimethylallyl diphosphate, the two building blocks for isoprenoid biosynthesis, occurs by two independent pathways in plants. The mevalonic pathway operates in the cytoplasm, and the methyl-d-erythritol 4-phosphate (MEP) pathway operates in plastids. Plastidic isoprenoids play essential roles in plant growth and development. Plants must regulate the biosynthesis of isoprenoids to fulfill metabolic requirements in specific tissues and developmental conditions. The regulatory events that modulate the plant MEP pathway are not well understood. In this article, we demonstrate that the CHLOROPLAST BIOGENESIS6 (CLB6) gene, previously shown to be required for chloroplast development, encodes 1-hydroxy-2-methyl-butenyl 4-diphosphate reductase, the last-acting enzyme of the MEP pathway. Comparative analysis of the expression levels of all MEP pathway gene transcripts and proteins in the clb6-1 mutant background revealed that posttranscriptional control modulates the levels of different proteins in this central pathway. Posttranscriptional regulation was also found during seedling development and during fosmidomycin inhibition of the pathway. Our results show that the first enzyme of the pathway, 1-deoxy-d-xylulose 5-phosphate synthase, is feedback regulated in response to the interruption of the flow of metabolites through the MEP pathway.

  15. Traditional Chinese medicine suppresses left ventricular hypertrophy by targeting extracellular signal-regulated kinases signaling pathway in spontaneously hypertensive rats

    Science.gov (United States)

    Xiong, Xingjiang; Yang, Xiaochen; Duan, Lian; Liu, Wei; Zhang, Yun; Liu, Yongmei; Wang, Pengqian; Li, Shengjie; Li, Xiaoke

    2017-01-01

    Chinese herbal medicine Bu-Shen-Jiang-Ya decoction (BSJYD) is reported to be beneficial for hypertension. Over expression of extracellular signal regulated kinases (ERK) pathway plays an important role in left ventricular hypertrophy (LVH). This study aimed to observe effects of BSJYD on LVH in spontaneously hypertensive rats (SHRs) and explore its possible mechanism on regulation of ERK pathway. Sixty 12-week-old SHRs were randomly allocated into 5 groups: BSJYD high dose group, middle dose group, low dose group, captopril group, and control group. Besides, a control group of Wistar-Kyoto rats was established. All rats were treated for 8 weeks. Systolic blood pressure (SBP), heart rate (HR), pathology, and left ventricular mass index (LVMI) were measured. Western blotting and Real-time PCR were used to assess the expressions of BDNF, Ras, ERK1/2, and c-fox levels. SBP and HR were significantly decreased compared with the control group and LVMI was markedly improved by BSJYD treatment in a dose-dependent manner. BSJYD inhibited the expression of BDNF, Ras, ERK1/2, and c-fox mRNA in LVH. In conclusion, BSJYD suppressed hypertension-induced cardiac hypertrophy by inhibiting the expression of ERK pathway. These changes in gene expression may be a possible mechanism by which BSJYD provides myocardial protection from hypertension. PMID:28225023

  16. Ets Factors Regulate Neural Stem Cell Depletion and Gliogenesis in Ras Pathway Glioma.

    Science.gov (United States)

    Breunig, Joshua J; Levy, Rachelle; Antonuk, C Danielle; Molina, Jessica; Dutra-Clarke, Marina; Park, Hannah; Akhtar, Aslam Abbasi; Kim, Gi Bum; Hu, Xin; Bannykh, Serguei I; Verhaak, Roel G W; Danielpour, Moise

    2015-07-14

    As the list of putative driver mutations in glioma grows, we are just beginning to elucidate the effects of dysregulated developmental signaling pathways on the transformation of neural cells. We have employed a postnatal, mosaic, autochthonous glioma model that captures the first hours and days of gliomagenesis in more resolution than conventional genetically engineered mouse models of cancer. We provide evidence that disruption of the Nf1-Ras pathway in the ventricular zone at multiple signaling nodes uniformly results in rapid neural stem cell depletion, progenitor hyperproliferation, and gliogenic lineage restriction. Abolishing Ets subfamily activity, which is upregulated downstream of Ras, rescues these phenotypes and blocks glioma initiation. Thus, the Nf1-Ras-Ets axis might be one of the select molecular pathways that are perturbed for initiation and maintenance in glioma.

  17. Structure, function and regulation of the enzymes in the starch biosynthetic pathway.

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, Jim

    2013-11-30

    Starch is the major reserve polysaccharide in nature and accounts for the majority of the caloric intact of humans. It is also gaining importance as a renewable and biodegradable industrial material. There is burgeoning interest in increasing the amount and altering the properties of the plant starches by plant genetic modification. A rational approach to this effort will require a detailed, atomic-level understanding of the enzymatic processes that produce the starch granule. The starch granule is a complex particle made up of alternating layers of crystalline and amorphous lamellae. It consists of two types of polymer, amylose, a polymer of relatively long chains of α-1,4-linked glucans that contain virtually no branches, and amylopectin, which is highly branched and contains much shorter chains. This complex structure is synthesized by the coordinate activities of the starch synthases (SS), which elongate the polysaccharide chain by addition of glucose units via α-1,4 linkages using ADP- glucose as a donor, and branching enzymes (BE), which branch the polysaccharide chain by cleavage of α₋1,4 linkages and subsequent re-attachment via α₋1,6 linkages. Several isoforms of both starch synthase (SS) and branching enzyme (BE) are found in plants, including SSI, SSII, SSIII and granule- bound SS (GBSS), and SBEI, SBEIIa and SBEIIb. These isoforms have different activities and substrate and product specificities and play different roles in creating the granule and determining the properties of the resulting starch. The overarching goal of this proposal is to begin to understand the regulation and specificities of these enzymes at the atomic level. High-resolution X-ray structures of these enzymes bound to substrates and products will be determined to visualize the molecular interactions responsible for the properties of the enzymes. Hypotheses regarding these issues will then be tested using mutagenesis and enzyme assays. To date, we have determined the

  18. miRNA expression analysis in cortical dysplasia: regulation of mTOR and LIS1 pathway.

    Science.gov (United States)

    Lee, Ji Yeoun; Park, Ae-Kyung; Lee, Eun-Sun; Park, Woong-Yang; Park, Sung-Hye; Choi, Jung Won; Phi, Ji Hoon; Wang, Kyu-Chang; Kim, Seung-Ki

    2014-03-01

    Cortical dysplasia (CD) is a common cause of epilepsy in children and is characterized by focal regions of malformed cerebral cortex. The pathogenesis and epileptogenesis of CD have not been fully elucidated, and in particular, the potential role of epigenetics has not been examined. miRNA microarray was performed on surgical specimens from CD (n=8) and normal control (n=2) children. A total of 10 differentially expressed miRNAs (DEmiRs) that were up-regulated in CD were identified including hsa-miR-21 and hsa-miR-155. The microarray results were validated using quantitative real-time PCR. After searching for the putative target genes of the DEmiRs, their biological significance was further evaluated by exploring the pathways in which the genes were enriched. The mammalian target of rapamycin (mTOR) signaling pathway was the most significantly associated, and the pathway of lissencephaly gene in neuronal migration and development was also noted. This study suggests a possible role for miRNAs in the pathogenesis of CD, especially in relation to the mTOR signaling pathway. Future studies on the epigenetic mechanisms underlying CD pathogenesis and epileptogenesis are needed.

  19. Pathways for Epidermal Cell Differentiation via the Homeobox Gene GLABRA2: Update on the Roles of the Classic Regulator

    Institute of Scientific and Technical Information of China (English)

    Lin Qing; Takashi Aoyama

    2012-01-01

    Recent plant development studies have identified regulatory pathways for epidermal cell differentiation in Arabidopsis thaliana.Interestingly,some of such pathways contain transcriptional networks with a common structure in which the homeobox gene GLABLA2 (GL2) is downstream of the transactivation complex consisting of MYB,bHLH,and WD40 proteins.Here,we review the role of GL2 as an output device of the conserved network,and update the knowledge of epidermal cell differentiation pathways downstream of GL2.Despite the consistent position of GL2 within the network,its role in epidermal tissues varies; in the root epidermis,GL2 promotes non-hair cell differentiation after cell pattern formation,whereas in the leaf epidermis,it is likely to be involved in both pattern formation and differentiation of trichomes.GL2 expression levels act as quantitative factors for initiation of cell differentiation in the root and leaf epidermis; the quantity of hairless cells in non-root hair cell files is reduced by g/2 mutations in a semi-dominant manner,and entopically additive expression of GL2 and a heterozygous g/2 mutation increase and decrease the number of trichomes,respectively.Although few direct target genes have been identified,evidence from genetic and expression analyses suggests that GL2 directly regulates genes with various hierarchies in epidermal cell differentiation pathways.

  20. Deep sequencing and in silico analyses identify MYB-regulated gene networks and signaling pathways in pancreatic cancer.

    Science.gov (United States)

    Azim, Shafquat; Zubair, Haseeb; Srivastava, Sanjeev K; Bhardwaj, Arun; Zubair, Asif; Ahmad, Aamir; Singh, Seema; Khushman, Moh'd; Singh, Ajay P

    2016-06-29

    We have recently demonstrated that the transcription factor MYB can modulate several cancer-associated phenotypes in pancreatic cancer. In order to understand the molecular basis of these MYB-associated changes, we conducted deep-sequencing of transcriptome of MYB-overexpressing and -silenced pancreatic cancer cells, followed by in silico pathway analysis. We identified significant modulation of 774 genes upon MYB-silencing (p networks by in silico analysis. Further analyses placed genes in our RNA sequencing-generated dataset to several canonical signalling pathways, such as cell-cycle control, DNA-damage and -repair responses, p53 and HIF1α. Importantly, we observed downregulation of the pancreatic adenocarcinoma signaling pathway in MYB-silenced pancreatic cancer cells exhibiting suppression of EGFR and NF-κB. Decreased expression of EGFR and RELA was validated by both qPCR and immunoblotting and they were both shown to be under direct transcriptional control of MYB. These observations were further confirmed in a converse approach wherein MYB was overexpressed ectopically in a MYB-null pancreatic cancer cell line. Our findings thus suggest that MYB potentially regulates growth and genomic stability of pancreatic cancer cells via targeting complex gene networks and signaling pathways. Further in-depth functional studies are warranted to fully understand MYB signaling in pancreatic cancer.

  1. A single transcription factor regulates evolutionarily diverse but functionally linked metabolic pathways in response to nutrient availability.

    Science.gov (United States)

    Schmid, Amy K; Reiss, David J; Pan, Min; Koide, Tie; Baliga, Nitin S

    2009-01-01

    During evolution, enzyme-coding genes are acquired and/or replaced through lateral gene transfer and compiled into metabolic pathways. Gene regulatory networks evolve to fine tune biochemical fluxes through such metabolic pathways, enabling organisms to acclimate to nutrient fluctuations in a competitive environment. Here, we demonstrate that a single TrmB family transcription factor in Halobacterium salinarum NRC-1 globally coordinates functionally linked enzymes of diverse phylogeny in response to changes in carbon source availability. Specifically, during nutritional limitation, TrmB binds a cis-regulatory element to activate or repress 113 promoters of genes encoding enzymes in diverse metabolic pathways. By this mechanism, TrmB coordinates the expression of glycolysis, TCA cycle, and amino-acid biosynthesis pathways with the biosynthesis of their cognate cofactors (e.g. purine and thiamine). Notably, the TrmB-regulated metabolic network includes enzyme-coding genes that are uniquely archaeal as well as those that are conserved across all three domains of life. Simultaneous analysis of metabolic and gene regulatory network architectures suggests an ongoing process of co-evolution in which TrmB integrates the expression of metabolic enzyme-coding genes of diverse origins.

  2. Curcumin suppresses NTHi-induced CXCL5 expression via inhibition of positive IKKβ pathway and up-regulation of negative MKP-1 pathway

    Science.gov (United States)

    Konduru, Anuhya S.; Lee, Byung-Cheol; Li, Jian-Dong

    2016-01-01

    Otitis media (OM) is the most common childhood bacterial infection, and leading cause of conductive hearing loss. Nontypeable Haemophilus influenzae (NTHi) is a major bacterial pathogen for OM. OM characterized by the presence of overactive inflammatory responses is due to the aberrant production of inflammatory mediators including C-X-C motif chemokine ligand 5 (CXCL5). The molecular mechanism underlying induction of CXCL5 by NTHi is unknown. Here we show that NTHi up-regulates CXCL5 expression by activating IKKβ-IκBα and p38 MAPK pathways via NF-κB nuclear translocation-dependent and -independent mechanism in middle ear epithelial cells. Current therapies for OM are ineffective due to the emergence of antibiotic-resistant NTHi strains and risk of side effects with prolonged use of immunosuppressant drugs. In this study, we show that curcumin, derived from Curcuma longa plant, long known for its medicinal properties, inhibited NTHi-induced CXCL5 expression in vitro and in vivo. Curcumin suppressed CXCL5 expression by direct inhibition of IKKβ phosphorylation, and inhibition of p38 MAPK via induction of negative regulator MKP-1. Thus, identification of curcumin as a potential therapeutic for treating OM is of particular translational significance due to the attractiveness of targeting overactive inflammation without significant adverse effects. PMID:27538525

  3. DMPD: Post-transcriptional regulation of proinflammatory proteins. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15075353 Post-transcriptional regulation of proinflammatory proteins. Anderson P, P...hillips K, Stoecklin G, Kedersha N. J Leukoc Biol. 2004 Jul;76(1):42-7. Epub 2004 Apr 1. (.png) (.svg) (.html) (.csml) Show Post...-transcriptional regulation of proinflammatory proteins. PubmedID 15075353 Title Post-tr

  4. GalX regulates the d-galactose oxido-reductive pathway in Aspergillus niger

    NARCIS (Netherlands)

    Gruben, B.S.; Zhou, M.; de Vries, R.P.

    2012-01-01

    Galactose catabolism in Aspergillus nidulans is regulated by at least two regulators, GalR and GalX. In Aspergillus niger only GalX is present, and its role in d-galactose catabolism in this fungus was investigated. Phenotypic and gene expression analysis of a wild type and a galX disruptant reveale

  5. A pathway from neuroticism to depression: examining the role of emotion regulation.

    Science.gov (United States)

    Yoon, Kathleen Lira; Maltby, John; Joormann, Jutta

    2013-09-01

    We examined whether the relation between neuroticism and the severity of depressive symptoms is mediated by emotion regulation. At the same time, we examined whether the type of emotion regulation strategy (maladaptive vs. adaptive) moderates the effects of neuroticism on depression severity. Community participants (N=533; 235 women and 298 men) completed a set of questionnaires over the Internet. We used structural equation modeling to examine the mediational role of emotion regulation in linking neuroticism and the levels of depressive symptoms. The well-documented relation between neuroticism and depression is mediated by individual differences in the use of different emotion regulation strategies. More specifically, the use of maladaptive forms of emotion regulation, but not reappraisal, fully mediated the association between neuroticism and the severity of depressive symptoms.

  6. Quercetin induces apoptosis by activating caspase-3 and regulating Bcl-2 and cyclooxygenase-2 pathways in human HL-60 cells

    Institute of Scientific and Technical Information of China (English)

    Guomin Niu; Songmei Yin; Shuangfeng Xie; Yiqing Li; Danian Nie; Liping Ma; Xiuju Wang; Yudan Wu

    2011-01-01

    Quercetin is one of the naturally occurring dietary flavo-nol compounds. It is present abundantly in plants and has chemopreventive and anticancer effects. To investigate its anticancer mechanism, we examined the activity of quercetin against acute leukemia cell line, HL-60. Our results showed that quercetin inhibited cell proliferation and induced apoptosis in a time- and dose-dependent manner. Furthermore, quercetin down-regulated the expression of anti-apoptosis protein Bcl-2 and up-regulated the expression of pro-apoptosis protein Bax. Caspase-3 was also activated by quercetin, which started a caspase-3-depended mitochodrial pathway to induce apoptosis. It was also found that quercetin inhibited the expression of the cycloocygenase-2 (Cox-2) mRNA and Cox-2 protein. Taken together, these findings suggested that quercetin induces apoptosis in a caspase-3-dependent pathway by inhibiting Cox-2 expression and regulates the expression of downstream apoptotic components, including Bcl-2 and Bax. Quercetin can be a potent and promising medicine which might be safely used in leukemia therapy.

  7. Regulation of the V-ATPase along the endocytic pathway occurs through reversible subunit association and membrane localization.

    Directory of Open Access Journals (Sweden)

    Céline Lafourcade

    Full Text Available The lumen of endosomal organelles becomes increasingly acidic when going from the cell surface to lysosomes. Luminal pH thereby regulates important processes such as the release of internalized ligands from their receptor or the activation of lysosomal enzymes. The main player in endosomal acidification is the vacuolar ATPase (V-ATPase, a multi-subunit transmembrane complex that pumps protons from the cytoplasm to the lumen of organelles, or to the outside of the cell. The active V-ATPase is composed of two multi-subunit domains, the transmembrane V(0 and the cytoplasmic V(1. Here we found that the ratio of membrane associated V(1/Vo varies along the endocytic pathway, the relative abundance of V(1 being higher on late endosomes than on early endosomes, providing an explanation for the higher acidity of late endosomes. We also found that all membrane-bound V-ATPase subunits were associated with detergent resistant membranes (DRM isolated from late endosomes, raising the possibility that association with lipid-raft like domains also plays a role in regulating the activity of the proton pump. In support of this, we found that treatment of cells with U18666A, a drug that leads to the accumulation of cholesterol in late endosomes, affected acidification of late endosome. Altogether our findings indicate that the activity of the vATPase in the endocytic pathway is regulated both by reversible association/dissociation and the interaction with specific lipid environments.

  8. CCR7 pathway induces epithelial-mesenchymal transition through up-regulation of Snail signaling in gastric cancer.

    Science.gov (United States)

    Zhang, Jianping; Zhou, Yunzhe; Yang, Yonggang

    2015-02-01

    The chemokine receptor 7 (CCR7) and Snail signaling have been linked to various types of cancers. The associations between these signalings and the epithelial-mesenchymal transition (EMT) are not clear in gastric cancer. Here, the expression of CCR7 and Snail was detected in gastric cancer by immunohistochemistry and Western blot. Meanwhile, gastric cancer cells were subjected to CCL19, si-control, and si-Snail treatment. Cell cycle, migration, and invasion were also analyzed. The expression patterns of CCR7 and Snail were similar in either gastric cancer tissues or cells. The increased expression of CCR7 was closely associated with the increased Snail expression, which both were closely correlated with metastasis, stage and differentiation, and poor prognosis. The increased p-ERK, p-AKT, Snail, and MMP9 expression and the decreased E-cadherin were confirmed in MGC803 cells in a dose-dependent manner in response to CCL19 treatment. However, the blockade of Snail abrogated the up-regulation of MMP9 and down-regulation of E-cadherin. CCR7-induced ERK and PI3K pathway regulated Snail signaling. Besides si-Snail treatment led to MGC803 cell cycle arrest and affected the migration and invasion. In conclusion, our study suggested that CCR7 promotes Snail expression to induce the EMT, resulting in cell cycle progression, migration, and invasion in gastric cancer. CCR7-Snail pathway provided more potential regimens for cancer therapy.

  9. Regulation of the small regulatory RNA MicA by ribonuclease III: a target-dependent pathway.

    Science.gov (United States)

    Viegas, Sandra C; Silva, Inês J; Saramago, Margarida; Domingues, Susana; Arraiano, Cecília M

    2011-04-01

    MicA is a trans-encoded small non-coding RNA, which downregulates porin-expression in stationary-phase. In this work, we focus on the role of endoribonucleases III and E on Salmonella typhimurium sRNA MicA regulation. RNase III is shown to regulate MicA in a target-coupled way, while RNase E is responsible for the control of free MicA levels in the cell. We purified both Salmonella enzymes and demonstrated that in vitro RNase III is only active over MicA when in complex with its targets (whether ompA or lamB mRNAs). In vivo, MicA is demonstrated to be cleaved by RNase III in a coupled way with ompA mRNA. On the other hand, RNase E is able to cleave unpaired MicA and does not show a marked dependence on its 5' phosphorylation state. The main conclusion of this work is the existence of two independent pathways for MicA turnover. Each pathway involves a distinct endoribonuclease, having a different role in the context of the fine-tuned regulation of porin levels. Cleavage of MicA by RNase III in a target-dependent fashion, with the concomitant decay of the mRNA target, strongly resembles the eukaryotic RNAi system, where RNase III-like enzymes play a pivotal role.

  10. MicroRNA-181b suppresses TAG via target IRS2 and regulating multiple genes in the Hippo pathway.

    Science.gov (United States)

    Chen, Zhi; Shi, HuaiPing; Sun, Shuang; Xu, HuiFen; Cao, DuoYao; Luo, Jun

    2016-10-15

    Milk fat metabolism is a complex procedure controlled by several factors. MiRNAs (microRNAs) regulate expression of genes and influence a series of biological procedures, such as fatty acid metabolism. Here we screened expression of goat mammary gland's miRNA during peak-lactation and late-lactation, and found that miR-181b expresses remarkably. Moreover, we illustrated that the over-expression of miR-181b impaired fat metabolism while the knockdown of miR-181b promoted fat metabolism in GMEC. These findings extend the discovery of miR-181b functioning in mediating adipocyte differentiation, by suggesting its role in impairing fat metabolism, which develops our cognition on the importance of miRNAs in milk fat metabolism and synthesis. In this study, we find that over expressed miR-181b impaired adipogenesis and inhibited miR-181b promoted adipogenesis in GMEC. Using Luciferase reporter assay and Western Blot, IRS2 was illustrated to be a miR-181b's potential target gene. What is interesting is that miR-181b regulates multiple key components in the Hippo pathway, such as LATS1 and YAP1 in GMECs. In conclusion, our findings indicated that miR-181b suppress fat metabolism by means of regulating multiple genes in the Hippo pathway and target IRS2, which promotes further study on the function of miRNAs in milk fat metabolism and synthesis.

  11. The Heparan and Heparin Metabolism Pathway is Involved in Regulation of Fatty Acid Composition

    Science.gov (United States)

    Six genes involved in the heparan sulfate and heparin metabolism pathway, DSEL (dermatan sulfate epimerase-like), EXTL1 (exostoses (multiple)-like 1), HS6ST1 (heparan sulfate 6-O-sulfotransferase 1), HS6ST3 (heparan sulfate 6-O-sulfotransferase 3), NDST3 (N-deacetylase/N-sulfotransferase (heparan gl...

  12. Inflammation-associated activation of coagulation and immune regulation by the protein C pathway.

    Science.gov (United States)

    Weiler, Hartmut

    2014-05-01

    The inflammation-induced activation of the protein C pathway provides negative feedback inhibition of coagulation and exerts coagulation-independent anti-inflammatory and cytoprotective effects. The balance between these activities of aPC modulates the outcome of diverse inflammatory diseases such as encephalitis, diabetes, and sepsis; and is affected by naturally occurring aPC-resistance of coagulation factor V Leiden.

  13. Regulation of Arginine-Ornithine Exchange and the Arginine Deiminase Pathway in Streptococcus lactis

    NARCIS (Netherlands)

    POOLMAN, B; DRIESSEN, AJM; KONINGS, WN

    1987-01-01

    Streptococcus lactis metabolizes arginine by the argiqine deiminase (ADI) pathway. Resting cells of S. lactis grown in the presence of galactose and arginine maintain a high intracellular ornithine pool in the absence of arginine and other exogenous energy sources. Addition of arginine results in a

  14. Yeast glucose pathways converge on the transcriptional regulation of trehalose biosynthesis

    Directory of Open Access Journals (Sweden)

    Apweiler Eva

    2012-06-01

    Full Text Available Abstract Background Cellular glucose availability is crucial for the functioning of most biological processes. Our understanding of the glucose regulatory system has been greatly advanced by studying the model organism Saccharomyces cerevisiae, but many aspects of this system remain elusive. To understand the organisation of the glucose regulatory system, we analysed 91 deletion mutants of the different glucose signalling and metabolic pathways in Saccharomyces cerevisiae using DNA microarrays. Results In general, the mutations do not induce pathway-specific transcriptional responses. Instead, one main transcriptional response is discerned, which varies in direction to mimic either a high or a low glucose response. Detailed analysis uncovers established and new relationships within and between individual pathways and their members. In contrast to signalling components, metabolic components of the glucose regulatory system are transcriptionally more frequently affected. A new network approach is applied that exposes the hierarchical organisation of the glucose regulatory system. Conclusions The tight interconnection between the different pathways of the glucose regulatory system is reflected by the main transcriptional response observed. Tps2 and Tsl1, two enzymes involved in the biosynthesis of the storage carbohydrate trehalose, are predicted to be the most downstream transcriptional components. Epistasis analysis of tps2Δ double mutants supports this prediction. Although based on transcriptional changes only, these results suggest that all changes in perceived glucose levels ultimately lead to a shift in trehalose biosynthesis.

  15. PIP2 in pancreatic β-cells regulates voltage-gated calcium channels by a voltage-independent pathway.

    Science.gov (United States)

    de la Cruz, Lizbeth; Puente, Erika I; Reyes-Vaca, Arturo; Arenas, Isabel; Garduño, Julieta; Bravo-Martínez, Jorge; Garcia, David E

    2016-10-01

    Phosphatidylinositol-4,5-bisphosphate (PIP2) is a membrane phosphoinositide that regulates the activity of many ion channels. Influx of calcium primarily through voltage-gated calcium (CaV) channels promotes insulin secretion in pancreatic β-cells. However, whether CaV channels are regulated by PIP2, as is the case for some non-insulin-secreting cells, is unknown. The purpose of this study was to investigate whether CaV channels are regulated by PIP2 depletion in pancreatic β-cells through activation of a muscarinic pathway induced by oxotremorine methiodide (Oxo-M). CaV channel currents were recorded by the patch-clamp technique. The CaV current amplitude was reduced by activation of the muscarinic receptor 1 (M1R) in the absence of kinetic changes. The Oxo-M-induced inhibition exhibited the hallmarks of voltage-independent regulation and did not involve PKC activation. A small fraction of the Oxo-M-induced CaV inhibition was diminished by a high concentration of Ca(2+) chelator, whereas ≥50% of this inhibition was prevented by diC8-PIP2 dialysis. Localization of PIP2 in the plasma membrane was examined by transfecting INS-1 cells with PH-PLCδ1, which revealed a close temporal association between PIP2 hydrolysis and CaV channel inhibition. Furthermore, the depletion of PIP2 by a voltage-sensitive phosphatase reduced CaV currents in a way similar to that observed following M1R activation. These results indicate that activation of the M1R pathway inhibits the CaV channel via PIP2 depletion by a Ca(2+)-dependent mechanism in pancreatic β- and INS-1 cells and thereby support the hypothesis that membrane phospholipids regulate ion channel activity by interacting with ion channels.

  16. GRK2 negatively regulates IGF-1R signaling pathway and cyclins' expression in HepG2 cells.

    Science.gov (United States)

    Wei, Zhengyu; Hurtt, Reginald; Gu, Tina; Bodzin, Adam S; Koch, Walter J; Doria, Cataldo

    2013-09-01

    G protein coupled receptor kinase 2 (GRK2) plays a central role in the regulation of a variety of important signaling pathways. Alternation of GRK2 protein level and activity casts profound effects on cell physiological functions and causes diseases such as heart failure, rheumatoid arthritis, and obesity. We have previously reported that overexpression of GRK2 has an inhibitory role in cancer cell growth. To further examine the role of GRK2 in cancer, in this study, we investigated the effects of reduced protein level of GRK2 on insulin-like growth factor 1 receptor (IGF-1R) signaling pathway in human hepatocellular carcinoma (HCC) HepG2 cells. We created a GRK2 knockdown cell line using a lentiviral vector mediated expression of GRK2 specific short hairpin RNA (shRNA). Under IGF-1 stimulation, HepG2 cells with reduced level of GRK2 showed elevated total IGF-1R protein expression as well as tyrosine phosphorylation of receptor. In addition, HepG2 cells with reduced level of GRK2 also demonstrated increased tyrosine phosphorylation of IRS1 at the residue 612 and increased phosphorylation of Akt, indicating a stronger activation of IGF-1R signaling pathway. However, HepG2 cells with reduced level of GRK2 did not display any growth advantage in culture as compared with the scramble control cells. We further detected that reduced level of GRK2 induced a small cell cycle arrest at G2/M phase by enhancing the expression of cyclin A, B1, and E. Our results indicate that GRK2 has contrasting roles on HepG2 cell growth by negatively regulating the IGF-1R signaling pathway and cyclins' expression.

  17. Wound induced tanscriptional regulation of benzylisoquinoline pathway and characterization of wound inducible PsWRKY transcription factor from Papaver somniferum.

    Directory of Open Access Journals (Sweden)

    Sonal Mishra

    Full Text Available Wounding is required to be made in the walls of the green seed pod of Opium poppy prior exudation of latex. To withstand this kind of trauma plants regulate expression of some metabolites through an induced transcript level. 167 unique wound-inducible ESTs were identified by a repetitive round of cDNA subtraction after 5 hours of wounding in Papaver somniferum seedlings. Further repetitive reverse northern analysis of these ESTs revealed 80 transcripts showing more than two fold induction, validated through semi-quantitative RT-PCR & real time expression analysis. One of the major classified categories among identified ESTs belonged to benzylisoquinoline transcripts. Tissue specific metabolite analysis of benzylisoquinoline alkaloids (BIAs in response to wounding revealed increased accumulation of narcotine and papaverine. Promoter analysis of seven transcripts of BIAs pathway showed the presence of W-box cis-element with the consensus sequence of TGAC, which is the proposed binding site for WRKY type transcription factors. One of the Wound inducible 'WRKY' EST isolated from our subtracted library was made full-length and named as 'PsWRKY'. Bacterially expressed PsWRKY interacted with the W-box element having consensus sequence TTGACT/C present in the promoter region of BIAs biosynthetic pathway genes. PsWRKY further activated the TYDC promoter in yeast and transiently in tobacco BY2 cells. Preferential expression of PsWRKY in straw and capsule and its interaction with consensus W-box element present in BIAs pathway gene transcripts suggest its possible involvement in the wound induced regulation of BIAs pathway.

  18. Inhibin alpha gene expression in human trophoblasts is regulated by interactions between TFAP2 and cAMP signaling pathways.

    Science.gov (United States)

    Depoix, Christophe L; Debiève, Frédéric; Hubinont, Corinne

    2014-11-01

    Inhibin α (Inha) gene expression is regulated, in rat granulosa cells, via a cyclic 3',5'-adenosine monophosphate (AMP)-response element (CRE) found in a region of the promoter that is homologous to the human INHA promoter. We previously found that during in vitro cytotrophoblast differentiation, human INHA gene expression was regulated by TFAP2A via association with an AP-2 site located upstream of this CRE. The aim of this study was to evaluate if the human INHA gene was also regulated by cAMP in trophoblasts, and to investigate the possible crosstalk between TFAP2 and cAMP signaling pathways in the regulation of INHA gene expression. Treatment with cAMP or forskolin increased INHA mRNA expression by 7- and 2-fold in primary cytotrophoblasts and choriocarcinoma-derived BeWo cells, respectively. Treatment with the protein kinase A inhibitor H-89 reduced forskolin-induced luciferase activity by ∼40% in BeWo cells transfected with an INHA promoter-driven luciferase reporter vector. TFAP2 overexpression increased basal luciferase activity, whereas the dominant repressor KCREB abolished it. Surprisingly, mutation of the CRE also eliminated the TFAP2-induced transcription, although TFAP2 overexpression was still able to increase forskolin-induced luciferase activity when the AP-2 binding site, but not the CRE site, was mutated. Thus, INHA gene expression is upregulated by cAMP via CRE in human trophoblasts, and TFAP2 regulates this expression by interacting with CRE.

  19. The transcriptional activators AraR and XlnR from Aspergillus niger regulate expression of pentose catabolic and pentose phosphate pathway genes

    NARCIS (Netherlands)

    Battaglia, Evy; Zhou, M.; de Vries, Ronald P; van den Brink, J.

    2014-01-01

    The pentose catabolic pathway (PCP) and the pentose phosphate pathway (PPP) are required for the conversion of pentose sugars in fungi and are linked via d-xylulose-5-phosphate. Previously, it was shown that the PCP is regulated by the transcriptional activators XlnR and AraR in Aspergillus niger. H

  20. Regulation of the CDP-choline pathway by sterol regulatory element binding proteins involves transcriptional and post-transcriptional mechanisms.

    Science.gov (United States)

    Ridgway, Neale D; Lagace, Thomas A

    2003-06-15

    The synthesis of phosphatidylcholine (PtdCho) by the CDP-choline pathway is under the control of the rate-limiting enzyme CTP:phosphocholine cytidylyltransferase (CCT). Sterol regulatory element binding proteins (SREBPs) have been proposed to regulate CCT at the transcriptional level, or via the synthesis of lipid activators or substrates of the CDP-choline pathway. To assess the contributions of these two mechanisms, we examined CCTalpha expression and PtdCho synthesis by the CDP-choline pathway in cholesterol and fatty acid auxotrophic CHO M19 cells inducibly expressing constitutively active nuclear forms of SREBP1a or SREBP2. Induction of either SREBP resulted in increased expression of mRNAs for sterol-regulated genes, elevated fatty acid and cholesterol synthesis (>10-50-fold) and increased PtdCho synthesis (2-fold). CCTalpha mRNA was increased 2-fold by enforced expression of SREBP1a or SREBP2. The resultant increase in CCTalpha protein and activity (2-fold) was restricted primarily to the soluble fraction of cells, and increased CCTalpha activity in vivo was not detected. Inhibition of the synthesis of fatty acids or their CoA esters by cerulenin or triacsin C respectively following SREBP induction effectively blocked the accompanying elevation in PtdCho synthesis. Thus PtdCho synthesis was driven by increased synthesis of fatty acids or a product thereof. These data show that transcriptional activation of CCTalpha is modest relative to that of other SREBP-regulated genes, and that stimulation of PtdCho synthesis by SREBPs in CHO cells is due primarily to increased fatty acid synthesis.

  1. Osmotic regulation and tissue localization of the myo-inositol biosynthesis pathway in tilapia (Oreochromis mossambicus) larvae.

    Science.gov (United States)

    Sacchi, Romina; Gardell, Alison M; Chang, Nicole; Kültz, Dietmar

    2014-10-01

    The myo-inositol biosynthesis (MIB) pathway converts glucose-6-phosphate to the compatible osmolyte myo-inositol, which protects cells from salinity stress. We exposed tilapia larvae just after yolk sac resorption to various hypersaline environments and recorded robust induction of the enzymes that constitute the MIB pathway, myo-inositol-phosphate synthase (MIPS), and inositol monophosphatase 1 (IMPA1). Strong up-regulation of these enzymes is evident at both mRNA (quantitative real-time PCR) and protein (densitometric analysis of Western blots) levels. The highest level of induction of these enzymes occurs at the highest salinity that larvae were exposed to (90 ppt). Less severe salinity stress causes a proportionately reduced induction of the MIB pathway. Two distinct MIPS mRNA variants are present in tilapia larvae and both are induced at comparable levels for all the salinity challenges tested (34, 70, and 90 ppt). Immunohistochemical localization of IMPA1 protein in sagittal sections of salinity stressed and control larvae identified tissues that are particularly potent in inducing the MIB pathway. These tissues include the skin (epidermis), gills, eye (ciliary epithelium) and heart. In particular, the epidermis directly facing the external milieu showed a very strong induction of IMPA1 immunoreactivity. IMPA1 induction in response to salinity stress was not observed in other tissues suggesting that tilapia larvae may also utilize compatible organic osmolytes other than solely myo-inositol for osmoprotection. We conclude that the MIB pathway plays an important role in protecting multiple (but not all) tissues of tilapia larvae from hyperosmotic salinity stress.

  2. Naringin promotes fracture healing through stimulation of angiogenesis by regulating the VEGF/VEGFR-2 signaling pathway in osteoporotic rats.

    Science.gov (United States)

    Song, Nan; Zhao, Zhihu; Ma, Xinlong; Sun, Xiaolei; Ma, Jianxiong; Li, Fengbo; Sun, Lei; Lv, Jianwei

    2017-01-05

    Postmenopausal osteoporosis is characterized by a reduction in the number of sinusoidal and arterial capillaries in the bone marrow and reduced bone perfusion. Thus, osteogenesis and angiogenesis are coupled in the process of osteoporosis formation and fracture healing. Naringin is the main ingredient of the root Rhizoma Drynariae, a traditional Chinese medicine, and it has potential effects on promoting fracture healing. However, whether naringin stimulates angiogenesis in the process of bone healing is unclear. Here, we show that naringin promotes fracture healing through stimulating angiogenesis by regulating the VEGF/VEGFR-2 signaling pathway in osteoporotic rats.

  3. Optogenetic signaling-pathway regulation through scattering skull using wavefront shaping

    CERN Document Server

    Yoon, Jonghee; Lee, KyeoReh; Kim, Nury; Kim, Jin Man; Park, Jongchan; Choi, Chulhee; Heo, Won Do; Park, YongKeun

    2015-01-01

    We introduce a non-invasive approach for optogenetic regulation in biological cells through highly scattering skull tissue using wavefront shaping. The wavefront of the incident light was systematically controlled using a spatial light modulator in order to overcome multiple light-scattering in a mouse skull layer and to focus light on the target cells. We demonstrate that illumination with shaped waves enables spatiotemporal regulation of intracellular Ca2+ level at the individual-cell level.

  4. Activation of Nrf2-Regulated Glutathione Pathway Genes by Ischemic Preconditioning

    Directory of Open Access Journals (Sweden)

    Karen F. S. Bell

    2011-01-01

    Full Text Available Prophylactic pharmacological activation of astrocytic gene expression driven by the transcription factor Nrf2 boosts antioxidant defences and protects against neuronal loss in ischemia and other disease models. However, the role of Nrf2 in mediating endogenous neuroprotective responses is less clear. We recently showed that Nrf2 is activated by mild oxidative stress in both rodent and human astrocytes. Moreover, brief exposure to ischemic conditions was found to activate Nrf2 both in vivo and in vitro, and this was found to contribute to neuroprotective ischemic preconditioning. Here we show that transient ischemic conditions in vitro and in vivo cause an increase in the expression of Nrf2 target genes associated with the glutathione pathway, including those involved in glutathione biosynthesis and cystine uptake. Taken together, these studies indicate that astrocytic Nrf2 may represent an important mediator of endogenous neuroprotective preconditioning pathways.

  5. MAPK signaling pathways regulate mitochondrial-mediated apoptosis induced by isoorientin in human hepatoblastoma cancer cells.

    Science.gov (United States)

    Yuan, Li; Wang, Jing; Xiao, Haifang; Wu, Wanqiang; Wang, Yutang; Liu, Xuebo

    2013-03-01

    Isoorientin (ISO) (CAS RN: 4261-42-1) is a flavonoid compound that can be extracted from several plant species, such as Phyllostachys pubescens, Patrinia, and Drosophyllum lusitanicum. ISO is able to induce apoptosis through mitochondrial dysfunction and inhibition of PI3K/Akt signaling pathway in HepG2 cells, however, the effects of ISO on MAPK signaling pathways remain unknown. The present study investigated the effects of ISO on this pathway, and the roles of MAPK kinases on mitochondrial-mediated apoptosis in HepG2 cells. The results showed that ISO induced cell death in a dose- and time-dependent manner, and induction apoptosis is main cause for ISO-induced cytotoxicity in HepG2 cells. ISO significantly inhibited the levels of ERK1/2 kinase and increased the expression of JNK and p38 kinases. Furthermore, U0126 (an ERK1/2 inhibitor) significantly enhanced the ISO-induced the Bax/Bcl-2 ratio, the release of cytochrome c to the cytosol fraction, and the levels of cleaved caspase-3. While SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor) markedly prevented the expression of these proteins induced by ISO. Furthermore, the ROS inhibitor (NAC) notably promoted the inhibited effect of ISO on the ERK1/2 kinase. NAC also suppressed the p-JNK and p-p38, but failed to reverse the effects of ISO. These results demonstrated for the first time that ISO induces apoptosis in HepG2 cells through inactivating ERK1/2 kinase and activating JNK and p38 kinases, and ROS stimulated by ISO is able to activate the MAPK singaling pathway as the upstream signaling molecules. Initiating event of the mitochondrial-mediated apoptosis induced by ISO is MAPK signals.

  6. Bacterial degradation of benzoate: cross-regulation between aerobic and anaerobic pathways

    OpenAIRE

    2012-01-01

    We have studied for the first time the transcriptional regulatory circuit that controls the expression of the box genes encoding the aerobic hybrid pathway used to assimilate benzoate via coenzyme A (CoA) derivatives in bacteria. The promoters responsible for the expression of the box cluster in the β-proteobacterium Azoarcus sp., their cognate transcriptional repressor, the BoxR protein, and the inducer molecule (benzoyl-CoA) have been characterized. The BoxR protein shows a significant sequ...

  7. Regulation of Metastasis and DNA Damage Resistance Pathways by Transposable Elements

    Science.gov (United States)

    2014-10-01

    Discovery Conference in Philadelphia. Philadelphia, PA. Sept. 2012 Interplay Between Chromatin Responses to DNA Double Strand Breaks and Transcription ...pathways. We have recently reported the phenomenon of Double Strand Break Induced Silencing in Cis (DISC), a process that relies on ATM and histone H2A... double - strand breaks (DSBs). Similar mechanisms of DSB silencing were involved in suppression of TEs following DNA damage, inspiring the hypothesis

  8. An Epigenetic Pathway Regulates Sensitivity of Breast Cancer Cells to HER2 Inhibition via FOXO/c-Myc Axis

    Science.gov (United States)

    Matkar, Smita; Sharma, Paras; Gao, Shubin; Gurung, Buddha; Katona, Bryson W; Liao, Jennifer; Muhammad, Abdul Bari; Kong, Xiang-Cheng; Wang, Lei; Jin, Guanghui; Dang, Chi; Hua, Xianxin

    2016-01-01

    SUMMARY Human epidermal growth factor receptor 2 (HER2) is upregulated in a subset of human breast cancers. However, the cancer cells often quickly develop an adaptive response to HER2 kinase inhibitors. We found that an epigenetic pathway involving MLL2 is crucial for growth of HER2+ cells and MLL2 reduces sensitivity of the cancer cells to a HER2 inhibitor, Lapatinib. Lapatinib-induced FOXO transcription factors, normally tumor-suppressing, paradoxically upregulate c-Myc epigenetically, in concert with a cascade of MLL2-associating epigenetic regulators, to dampen sensitivity of the cancer cells to Lapatinib. An epigenetic inhibitor suppressing c-Myc synergizes with Lapatinib to suppress cancer growth in vivo, partly by repressing the FOXO/c-Myc axis, unraveling an epigenetically regulated FOXO/c-Myc axis as a potential target to improve therapy. PMID:26461093

  9. Structural pathways of cytokines may illuminate their roles in regulation of cancer development and immunotherapy.

    Science.gov (United States)

    Guven-Maiorov, Emine; Acuner-Ozbabacan, Saliha Ece; Keskin, Ozlem; Gursoy, Attila; Nussinov, Ruth

    2014-03-25

    Cytokines are messengers between tissues and the immune system. They play essential roles in cancer initiation, promotion, metastasis, and immunotherapy. Structural pathways of cytokine signaling which contain their interactions can help understand their action in the tumor microenvironment. Here, our aim is to provide an overview of the role of cytokines in tumor development from a structural perspective. Atomic details of protein-protein interactions can help in understanding how an upstream signal is transduced; how higher-order oligomerization modes of proteins can influence their function; how mutations, inhibitors or antagonists can change cellular consequences; why the same protein can lead to distinct outcomes, and which alternative parallel pathways can take over. They also help to design drugs/inhibitors against proteins de novo or by mimicking natural antagonists as in the case of interferon-γ. Since the structural database (PDB) is limited, structural pathways are largely built from a series of predicted binary protein-protein interactions. Below, to illustrate how protein-protein interactions can help illuminate roles played by cytokines, we model some cytokine interaction complexes exploiting a powerful algorithm (PRotein Interactions by Structural Matching-PRISM).

  10. Structural Pathways of Cytokines May Illuminate Their Roles in Regulation of Cancer Development and Immunotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Guven-Maiorov, Emine; Acuner-Ozbabacan, Saliha Ece; Keskin, Ozlem; Gursoy, Attila [Center for Computational Biology and Bioinformatics and College of Engineering, Koc University, Rumelifeneri Yolu, 34450 Sariyer Istanbul (Turkey); Nussinov, Ruth, E-mail: nussinor@helix.nih.gov [Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, MD 21702 (United States); Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978 (Israel)

    2014-03-25

    Cytokines are messengers between tissues and the immune system. They play essential roles in cancer initiation, promotion, metastasis, and immunotherapy. Structural pathways of cytokine signaling which contain their interactions can help understand their action in the tumor microenvironment. Here, our aim is to provide an overview of the role of cytokines in tumor development from a structural perspective. Atomic details of protein-protein interactions can help in understanding how an upstream signal is transduced; how higher-order oligomerization modes of proteins can influence their function; how mutations, inhibitors or antagonists can change cellular consequences; why the same protein can lead to distinct outcomes, and which alternative parallel pathways can take over. They also help to design drugs/inhibitors against proteins de novo or by mimicking natural antagonists as in the case of interferon-γ. Since the structural database (PDB) is limited, structural pathways are largely built from a series of predicted binary protein-protein interactions. Below, to illustrate how protein-protein interactions can help illuminate roles played by cytokines, we model some cytokine interaction complexes exploiting a powerful algorithm (PRotein Interactions by Structural Matching—PRISM)

  11. Lafora disease proteins laforin and malin negatively regulate the HIPK2-p53 cell death pathway.

    Science.gov (United States)

    Upadhyay, Mamta; Gupta, Smriti; Bhadauriya, Pratibha; Ganesh, Subramaniam

    2015-08-14

    Lafora disease (LD) is an autosomal recessive, progressive, and fatal form of a neurodegenerative disorder characterized by the presence of Lafora polyglucosan bodies. LD is caused by defects in either the laforin protein phosphatase or the malin E3 ubiquitin ligase. Laforin and malin were shown play key roles in proteolytic processes, unfolded stress response, and glycogen metabolism. Therefore, the LD proteins laforin and malin are thought to function as pro-survival factors and their loss thus could result in neurodegeneration. To understand the molecular pathway leading to the cell death in LD, in the present study, we investigated the possible role of LD proteins in the p53-mediated cell death pathway. We show that loss of laforin or malin results in the increased level and activity of p53, both in cellular and animal models of LD, and that this is primarily due to the increased levels of Hipk2, a proapoptotic activator of p53. Overexpression of laforin or malin confers protection against Hipk2-mediated cell death by targeting the Hipk2 to the cytoplasmic compartment. Taken together, our study strengthens the notion that laforin and malin are pro-survival factors, and that the activation of Hipk2-p53 cell death pathway might underlie neurodegeneration in LD.

  12. Hippo pathway/Yap regulates primary enamel knot and dental cusp patterning in tooth morphogenesis.

    Science.gov (United States)

    Kwon, Hyuk-Jae Edward; Li, Liwen; Jung, Han-Sung

    2015-11-01

    The shape of an individual tooth crown is primarily determined by the number and arrangement of its cusps, i.e., cusp patterning. Enamel knots that appear in the enamel organ during tooth morphogenesis have been suggested to play important roles in cusp patterning. Animal model studies have shown that the Hippo pathway effector Yap has a critical function in tooth morphogenesis. However, the role of the Hippo pathway/Yap in cusp patterning has not been well documented and its specific roles in tooth morphogenesis remain unclear. Here, we provide evidence that Yap is a key mediator in tooth cusp patterning. We demonstrate a correlation between Yap localization and cell proliferation in developing tooth germs. We also show that, between the cap stage and bell stage, Yap is crucial for the suppression of the primary enamel knot and for the patterning of secondary enamel knots, which are the future cusp regions. When Yap expression is stage-specifically knocked down during the cap stage, the activity of the primary enamel knot persists into the bell-stage tooth germ, leading to ectopic cusp formation. Our data reveal the importance of the Hippo pathway/Yap in enamel knots and in the proper patterning of tooth cusps.

  13. TRIM-9 functions in the UNC-6/UNC-40 pathway to regulate ventral guidance

    Institute of Scientific and Technical Information of China (English)

    Song Song; Qinglan Ge; Jinbo Wang; Haiyang Chen; Sanyuan Tang; Junfeng Bi; Xia Li; Qi Xie; Xun Huang

    2011-01-01

    TRIpartite Motif (TRIM) family proteins are ring finger domain-containing, multi-domain proteins implicated in many biological processes.Members of the TRIM-9/C-I subfamily of TRIM proteins, including TRIM-9, MIDI and MID2, have neuronal functions and are associated with neurological diseases. To explore whether the functions of C-I TRIM proteins are conserved in invertebrates, we analyzed Caenorhabditis elegans and Drosophila trim-9 mutants. C. elegans trim-9 mutants exhibit defects in the ventral guidance of hermaphrodite specific neuron (HSN) and the touch neuron AVM. Further genetic analyses indicate that TRIM-9 participates in the UNC-6-UNC-40 attraction pathway.Asymmetric distribution of UNC-40 during HSN development is normal in trim-9 mutants. However, the asymmetric localization of MIG-10,a downstream effector of UNC-40, is abolished in trim-9 mutants. These results suggest that TRIM-9 functions upstream of MIG-1 0 in the UNC40 pathway. Moreover, we showed that TRIM-9 exhibits E3 ubiquitin ligase activity in vitro and this activity is important for TRIM-9 function in vivo. Additionally, we found that Drosophila trim-9 is required for the midline attraction of a group of sensory neuron axons. Over-expression of the Netrin/UNC-6 receptor Frazzled suppresses the guidance defects in trim-9 mutants. Our study reveals an evolutionarily conserved function of TRIM-9 in the UNC-40/Frazzled-mediated UNC-6/Netrin attraction pathway.

  14. Convergent Signaling Pathways Regulate Parathyroid Hormone and Fibroblast Growth Factor-23 Action on NPT2A-mediated Phosphate Transport.

    Science.gov (United States)

    Sneddon, W Bruce; Ruiz, Giovanni W; Gallo, Luciana I; Xiao, Kunhong; Zhang, Qiangmin; Rbaibi, Youssef; Weisz, Ora A; Apodaca, Gerard L; Friedman, Peter A

    2016-09-02

    Parathyroid hormone (PTH) and FGF23 are the primary hormones regulating acute phosphate homeostasis. Human renal proximal tubule cells (RPTECs) were used to characterize the mechanism and signaling pathways of PTH and FGF23 on phosphate transport and the role of the PDZ protein NHERF1 in mediating PTH and FGF23 effects. RPTECs express the NPT2A phosphate transporter, αKlotho, FGFR1, FGFR3, FGFR4, and the PTH receptor. FGFR1 isoforms are formed from alternate splicing of exon 3 and of exon 8 or 9 in Ir-like loop 3. Exon 3 was absent, but mRNA containing both exons 8 and 9 is present in cytoplasm. Using an FGFR1c-specific antibody together with mass spectrometry analysis, we show that RPTECs express FGFR-β1C. The data are consistent with regulated FGFR1 splicing involving a novel cytoplasmic mechanism. PTH and FGF23 inhibited phosphate transport in a concentration-dependent manner. At maximally effective concentrations, PTH and FGF23 equivalently decreased phosphate uptake and were not additive, suggesting a shared mechanism of action. Protein kinase A or C blockade prevented PTH but not FGF23 actions. Conversely, inhibiting SGK1, blocking FGFR dimerization, or knocking down Klotho expression disrupted FGF23 actions but did not interfere with PTH effects. C-terminal FGF23(180-251) competitively and selectively blocked FGF23 action without disrupting PTH effects. However, both PTH and FGF23-sensitive phosphate transport were abolished by NHERF1 shRNA knockdown. Extended treatment with PTH or FGF23 down-regulated NPT2A without affecting NHERF1. We conclude that FGFR1c and PTHR signaling pathways converge on NHERF1 to inhibit PTH- and FGF23-sensitive phosphate transport and down-regulate NPT2A.

  15. Regulation of the ERK pathway in the dentate gyrus by in vivo dopamine D1 receptor stimulation requires glutamatergic transmission.

    Science.gov (United States)

    Gangarossa, Giuseppe; Valjent, Emmanuel

    2012-11-01

    Acute systemic administration of the dopamine D1/D5 receptors (D1Rs) agonist, SKF81297, activates the extracellular signal-regulated protein kinases (ERK) pathway selectively in the granule cells of the dentate gyrus. In this study, we examined the mechanisms involved in this regulation and investigated the molecular components that could promote ERK-dependent transcription and translation. SKF81297 induced phosphorylation of ERK and histone H3 required intact glutamatergic transmission. Blockade of glutamate release achieved by the mGluR2/3 agonist, LY354740 or the selective adenosine A1R agonist, CCPA as well as neurotoxic lesions of lateral entorhinal cortex reduced the ability of SKF81297 to induce ERK activation in the dentate gyrus. This activation required the combined stimulation of NR2B-containing NMDARs, mGluR1 and mGluR5. SKF81297 evoked phosphorylation of the ribosomal protein S6 (rpS6) selectively at the Ser235/236 site while the Ser240/244 site remains unchanged. The SKF81297 induced increased phosphorylation of rpS6 was dependent on PKC and ERK/p90RSK activation. Surprisingly, administration of D1Rs agonist suppressed mTORC1/p70S6K pathway suggesting an mTOR-independent regulation of rpS6 phosphorylation. Taken together, our results show that intact glutamatergic transmission plays a major role in the regulation of ERK-dependent phosphorylation of histone H3 and rpS6 observed in the mouse dentate gyrus after systemic administration of SKF81297.

  16. Hepatitis C virus core protein induces energy metabolism disorders of hepatocytes by down-regulation of silent mating type information regulation 2 homolog-1 and adenosine monophosphate-acti vated protein kinase signaling pathway

    Institute of Scientific and Technical Information of China (English)

    于建武

    2013-01-01

    Objective To study the role of silent mating type information regulation2homotog-1(SIRT1)-adenosine monophosphate(AMP)-activated protein kinase(AMPK) signaling pathway in hepatitis C virus core protein(HCV-core)induced energy metabolism disorders

  17. Nitric oxide modulates hypoxic pulmonary smooth muscle cell proliferation and apoptosis by regulating carbon monoxide pathway

    Institute of Scientific and Technical Information of China (English)

    Yan-fei WANG; Hong TIAN; Chao-shu TANG; Hong-fang JIN; Jun-bao DU

    2007-01-01

    Aim: To explore the role of carbon monoxide (CO) in the regulation of hypoxic pulmonary artery smooth muscle cell (PASMC) proliferation and apoptosis by nitric oxide (NO). Methods: PASMC of Wistar rats was cultured in vitro in the presence of a NO donor, sodium nitroprusside, or an inhibitor of heme oxygenase (HO), zinc protoporphyrin-IX, or under both normoxic and hypoxic conditions.Nitrite and carboxyhemoglobin in PASMC medium were detected with spectrophotometry. The proliferating and apoptotic percentage of PASMC was measured by flow cytometry. The expression of HO-1 mRNA in PASMC was analyzed by fluorescent real-time quantitative PCR, and the proliferating cell nuclear antigen and caspase-3 were examined by immunocytochemical analysis. Results: The results showed that hypoxia suppressed NO generation from PASMC, which promoted hypoxic PASMC proliferation and induced apoptosis. Meanwhile, hy-poxia induced HO-1 expression in PASMC and promoted CO production from PASMC, which inhibited PASMC proliferation and regulated PASMC apoptosis. NO upregulated the expression of HO-1 mRNA in hypoxic PASMC; NO also inhib-ited proliferation and promoted apoptosis of hypoxic PASMC, possibly by regu-lating the production of CO. Conclusion: The results indicated that CO could inhibit proliferation and regulate apoptosis of PASMC, and NO inhibited prolifera-tion and promoted apoptosis of hypoxic PASMC, possibly by regulating the pro-duction of CO.

  18. Dietary Regulation of Keap1/Nrf2/ARE Pathway: Focus on Plant-Derived Compounds and Trace Minerals

    Directory of Open Access Journals (Sweden)

    Amanda L. Stefanson

    2014-09-01

    Full Text Available It has become increasingly evident that chronic inflammation underpins the development of many chronic diseases including cancer, cardiovascular disease and type 2 diabetes. Oxidative stress is inherently a biochemical dysregulation of the redox status of the intracellular environment, which under homeostatic conditions is a reducing environment, whereas inflammation is the biological response to oxidative stress in that the cell initiates the production of proteins, enzymes, and other compounds to restore homeostasis. At the center of the day-to-day biological response to oxidative stress is the Keap1/Nrf2/ARE pathway, which regulates the transcription of many antioxidant genes that preserve cellular homeostasis and detoxification genes that process and eliminate carcinogens and toxins before they can cause damage. The Keap1/Nrf2/ARE pathway plays a major role in health resilience and can be made more robust and responsive by certain dietary factors. Transient activation of Nrf2 by dietary electrophilic phytochemicals can upregulate antioxidant and chemopreventive enzymes in the absence of actual oxidative stress inducers. Priming the Keap1/Nrf2/ARE pathway by upregulating these enzymes prior to oxidative stress or xenobiotic encounter increases cellular fitness to respond more robustly to oxidative assaults without activating more intense inflammatory NFκB-mediated responses.

  19. Interactions between the inositol 1,4,5-trisphosphate and cyclic AMP signaling pathways regulate larval molting in Drosophila.

    Science.gov (United States)

    Venkatesh, K; Siddhartha, G; Joshi, R; Patel, S; Hasan, G

    2001-05-01

    Larval molting in Drosophila, as in other insects, is initiated by the coordinated release of the steroid hormone ecdysone, in response to neural signals, at precise stages during development. In this study we have analyzed, using genetic and molecular methods, the roles played by two major signaling pathways in the regulation of larval molting in Drosophila. Previous studies have shown that mutants for the inositol 1,4,5-trisphosphate receptor gene (itpr) are larval lethals. In addition they exhibit delays in molting that can be rescued by exogenous feeding of 20-hydroxyecdysone. Here we show that mutants for adenylate cyclase (rut) synergize, during larval molting, with itpr mutant alleles, indicating that both cAMP and InsP(3) signaling pathways function in this process. The two pathways act in parallel to affect molting, as judged by phenotypes obtained through expression of dominant negative and dominant active forms of protein kinase A (PKA) in tissues that normally express the InsP(3) receptor. Furthermore, our studies predict the existence of feedback inhibition through protein kinase A on the InsP(3) receptor by increased levels of 20-hydroxyecdysone.

  20. A genome-wide RNAi screen reveals MAP kinase phosphatases as key ERK pathway regulators during embryonic stem cell differentiation.

    Directory of Open Access Journals (Sweden)

    Shen-Hsi Yang

    Full Text Available Embryonic stem cells and induced pluripotent stem cells represent potentially important therapeutic agents in regenerative medicine. Complex interlinked transcriptional and signaling networks control the fate of these cells towards maintenance of pluripotency or differentiation. In this study we have focused on how mouse embryonic stem cells begin to differentiate and lose pluripotency and, in particular, the role that the ERK MAP kinase and GSK3 signaling pathways play in this process. Through a genome-wide siRNA screen we have identified more than 400 genes involved in loss of pluripotency and promoting the onset of differentiation. These genes were functionally associated with the ERK and/or GSK3 pathways, providing an important resource for studying the roles of these pathways in controlling escape from the pluripotent ground state. More detailed analysis identified MAP kinase phosphatases as a focal point of regulation and demonstrated an important role for these enzymes in controlling ERK activation kinetics and subsequently determining early embryonic stem cell fate decisions.

  1. Formin-like2 regulates Rho/ROCK pathway to promote actin assembly and cell invasion of colorectal cancer.

    Science.gov (United States)

    Zeng, Yuanfeng; Xie, Huijun; Qiao, Yudan; Wang, Jianmei; Zhu, Xiling; He, Guoyang; Li, Yuling; Ren, Xiaoli; Wang, Feifei; Liang, Li; Ding, Yanqing

    2015-10-01

    Formin-like2 (FMNL2) is a member of the diaphanous-related formins family, which act as effectors and upstream modulators of Rho GTPases signaling and control the actin-dependent processes, such as cell motility or invasion. FMNL2 has been identified as promoting the motility and metastasis in colorectal carcinoma (CRC). However, whether FMNL2 regulates Rho signaling to promote cancer cell invasion remains unclear. In this study, we demonstrated an essential role for FMNL2 in the activations of Rho/ROCK pathway, SRF transcription or actin assembly, and subsequent CRC cell invasion. FMNL2 could activate Rho/ROCK pathway, and required ROCK to promote CRC cell invasion. Moreover, FMNL2 promoted the formation of filopodia and stress fiber, and activated the SRF transcription in a Rho-dependent manner. We also demonstrated that FMNL2 was necessary for LPA-induced invasion, RhoA/ROCK activation, actin assembly and SRF activation. FMNL2 was an essential component of LPA signal transduction toward RhoA by directly interacting with LARG. LARG silence inhibited RhoA/ROCK pathway and CRC cell invasion. Collectively, these data indicate that FMNL2, acting as upstream of RhoA by interacting with LARG, can promote actin assembly and CRC cell invasion through a Rho/ROCK-dependent mechanism.

  2. The PAF complex and Prf1/Rtf1 delineate distinct Cdk9-dependent pathways regulating transcription elongation in fission yeast.

    Directory of Open Access Journals (Sweden)

    Jean Mbogning

    Full Text Available Cyclin-dependent kinase 9 (Cdk9 promotes elongation by RNA polymerase II (RNAPII, mRNA processing, and co-transcriptional histone modification. Cdk9 phosphorylates multiple targets, including the conserved RNAPII elongation factor Spt5 and RNAPII itself, but how these different modifications mediate Cdk9 functions is not known. Here we describe two Cdk9-dependent pathways in the fission yeast Schizosaccharomyces pombe that involve distinct targets and elicit distinct biological outcomes. Phosphorylation of Spt5 by Cdk9 creates a direct binding site for Prf1/Rtf1, a transcription regulator with functional and physical links to the Polymerase Associated Factor (PAF complex. PAF association with chromatin is also dependent on Cdk9 but involves alternate phosphoacceptor targets. Prf1 and PAF are biochemically separate in cell extracts, and genetic analyses show that Prf1 and PAF are functionally distinct and exert opposing effects on the RNAPII elongation complex. We propose that this opposition constitutes a Cdk9 auto-regulatory mechanism, such that a positive effect on elongation, driven by the PAF pathway, is kept in check by a negative effect of Prf1/Rtf1 and downstream mono-ubiquitylation of histone H2B. Thus, optimal RNAPII elongation may require balanced action of functionally distinct Cdk9 pathways.

  3. Leptin regulates proliferation and apoptosis of colorectal carcinoma through PI3K/Akt/mTOR signalling pathway

    Indian Academy of Sciences (India)

    Di Wang; Jian Chen; Hui Chen; Zhi Duan; Qimei Xu; Meiyan Wei; Lianghua Wang; Meizuo Zhong

    2012-03-01

    Epidemiological studies have indicated that obesity is associated with colorectal cancer. The obesity hormone leptin is considered as a key mediator for cancer development and progression. The present study aims to investigate regulatory effects of leptin on colorectal carcinoma. The expression of leptin and its receptor Ob-R was examined by immunohistochemistry in 108 Chinese patients with colorectal carcinoma. The results showed that leptin/Ob-R expression was significantly associated with T stage, TNM stage, lymph node metastasis, distant metastasis, differentiation and expression of p-mTOR, p-70S6 kinase, and p-Akt. Furthermore, the effects of leptin on proliferation and apoptosis of HCT-116 colon carcinoma cells were determined. The results showed that leptin could stimulate the proliferation and inhibit the apoptosis of HCT-116 colon cells through the PI3K/Akt/mTOR pathway. Ly294002 (a PI3K inhibitor) and rapamycin (an mTOR inhibitor) could prevent the regulatory effects of leptin on the proliferation and apoptosis of HCT-116 cells via abrogating leptin-mediated PI3K/Akt/mTOR pathway. All these results indicated that leptin could regulate proliferation and apoptosis of colorectal carcinoma through the PI3K/Akt/mTOR signalling pathway.

  4. The Tpr protein regulates export of mRNAs with retained introns that traffic through the Nxf1 pathway.

    Science.gov (United States)

    Coyle, John H; Bor, Yeou-Cherng; Rekosh, David; Hammarskjold, Marie-Louise

    2011-07-01

    Post-transcriptional regulation of mRNA includes restriction mechanisms to prevent export and expression of mRNAs that are incompletely spliced. Here we present evidence that the mammalian protein Tpr is involved in this restriction. To study the role of Tpr in export of mRNA with retained introns, we used reporters in which the mRNA was exported either via the Nxf1/Nxt1 pathway using a CTE or via the Crm1 pathway using Rev/RRE. Our data show that even modest knockdown of Tpr using RNAi leads to a significant increase in export and translation from the mRNA containing the CTE. In contrast, Tpr perturbation has no effect on export of mRNA containing the RRE, either in the absence or presence of Rev. Also, no effects were observed on export of a completely spliced mRNA. Taken together, our results indicate that Tpr plays an important role in quality control of mRNA trafficked on the Nxf1 pathway.

  5. Overexpression of LRIG1 regulates PTEN via MAPK/MEK signaling pathway in esophageal squamous cell carcinoma

    Science.gov (United States)

    Jiang, Xiaofang; Li, Huiwu

    2016-01-01

    The present study aimed to evaluate the role of leucine-rich repeats and immunoglobulin-like domain protein 1 (LRIG1) in the regulation of phosphatase and tensin homolog (PTEN) expression in esophageal carcinogenesis. LRIG1 was overexpressed in esophageal squamous cell carcinoma (ESCC) cell lines, and the effect of LRIG1 overexpression on the mRNA and protein expression levels of PTEN was evaluated by reverse transcription-quantitative polymerase chain reaction and western blotting. Furthermore, the effects of LRIG1 overexpression on the cell cycle distribution and apoptosis of ESCC cells were examined by flow cytometry. Various cell signaling pathway inhibitors were used to assess the effects of LRIG1 on downstream signaling in ESCC cell lines. In addition, the association between LRIG1 and PTEN expression was examined in 48 samples from patients with ESCC. LRIG1 overexpression was demonstrated to downregulate PTEN expression in ESCC cell lines, and promote their proliferation and inhibit apoptosis. In addition, LRIG1-mediated suppression of PTEN expression was inhibited by the U0126 inhibitor, which suggests that LRIG1 may inhibit the activation of PTEN signaling molecules by triggering the mitogen-activated protein kinase (MAPK)/MAPK kinase 1 (MEK) signaling pathway. In conclusion, the present study demonstrated that overexpression of LRIG1 significantly and adversely affected the survival of ESCC cells, and that the MAPK/MEK signaling pathway may be responsible for the repression of PTEN expression and function. PMID:27698691

  6. Combinatorial control of diverse metabolic and physiological functions by transcriptional regulators of the yeast sulfur assimilation pathway.

    Science.gov (United States)

    Petti, Allegra A; McIsaac, R Scott; Ho-Shing, Olivia; Bussemaker, Harmen J; Botstein, David

    2012-08-01

    Methionine abundance affects diverse cellular functions, including cell division, redox homeostasis, survival under starvation, and oxidative stress response. Regulation of the methionine biosynthetic pathway involves three DNA-binding proteins-Met31p, Met32p, and Cbf1p. We hypothesized that there exists a "division of labor" among these proteins that facilitates coordination of methionine biosynthesis with diverse biological processes. To explore combinatorial control in this regulatory circuit, we deleted CBF1, MET31, and MET32 individually and in combination in a strain lacking methionine synthase. We followed genome-wide gene expression as these strains were starved for methionine. Using a combination of bioinformatic methods, we found that these regulators control genes involved in biological processes downstream of sulfur assimilation; many of these processes had not previously been documented as methionine dependent. We also found that the different factors have overlapping but distinct functions. In particular, Met31p and Met32p are important in regulating methionine metabolism, whereas p functions as a "generalist" transcription factor that is not specific to methionine metabolism. In addition, Met31p and Met32p appear to regulate iron-sulfur cluster biogenesis through direct and indirect mechanisms and have distinguishable target specificities. Finally, CBF1 deletion sometimes has the opposite effect on gene expression from MET31 and MET32 deletion.

  7. Multiple motifs regulate the trafficking of GABA(B) receptors at distinct checkpoints within the secretory pathway.

    Science.gov (United States)

    Restituito, Sophie; Couve, Andrés; Bawagan, Hinayana; Jourdain, Sabine; Pangalos, Menelas N; Calver, Andrew R; Freeman, Katie B; Moss, Stephen J

    2005-04-01

    gamma-Aminobutyric acid type B receptors (GABA(B)) are G-protein-coupled receptors that mediate GABAergic inhibition in the brain. Their functional expression is dependent upon the formation of heterodimers between GABA(B)R1 and GABA(B)R2 subunits, a process that occurs within the endoplasmic reticulum (ER). However, the mechanisms that regulate receptor surface expression remain largely unknown. Here, we demonstrate that access to the cell surface for GABA(B)R1 is sequentially controlled by an RSR(R) motif and a LL motif within its cytoplasmic domain. In addition, we reveal that msec7-1, a guanine-nucleotide-exchange factor (GEF) for the ADP-ribosylation factor (ARF) family of GTPases, critical regulators of vesicular membrane trafficking, interacts with GABA(B)R1 via the LL motif in this subunit. Finally, we establish that msec7-1 modulates the cell surface expression of GABA(B) receptors, a process that is dependent upon the integrity of the LL motif in GABA(B)R1. Together, our results demonstrate that the cell surface expression of the GABA(B)R1 subunit is regulated by multiple motifs, which act at distinct checkpoints in the secretory pathway, and also suggest a novel role for msec7-1 in regulating the membrane trafficking of GABA(B)R1 subunits.

  8. ins-7 Gene expression is partially regulated by the DAF-16/IIS signaling pathway in Caenorhabditis elegans under celecoxib intervention.

    Science.gov (United States)

    Zheng, Shanqing; Liao, Sentai; Zou, Yuxiao; Qu, Zhi; Liu, Fan

    2014-01-01

    DAF-16 target genes are employed as reporters of the insulin/IGF-1 like signal pathway (IIS), and this is notably true when Caenorhabditis elegans (C. elegans) is used to study the action of anti-aging compounds on IIS activity. However, some of these genes may not be specific to DAF-16, even if their expression levels are altered when DAF-16 is activated. Celecoxib was reported to extend the lifespan of C. elegans through activation of DAF-16. Our results confirmed the function of celecoxib on aging; however, we found that the expression of ins-7, a DAF-16 target gene, was abnormally regulated by celecoxib. ins-7 plays an important role in regulating aging, and its expression is suppressed in C. elegans when DAF-16 is activated. However, we found that celecoxib upregulated the expression of ins-7 in contrast to its role in DAF-16 activation. Our subsequent analysis indicated that the expression level of ins-7 in C. elegans was negatively regulated by DAF-16 activity. Additionally, its expression was also positively regulated by DAF-16-independent mechanisms, at least following external pharmacological intervention. Our study suggests that ins-7 is not a specific target gene of DAF-16, and should not be chosen as a reporter for IIS activity. This conclusion is important in the study of INSs on aging in C. elegans, especially under the circumstance of drug intervention.

  9. A Potassium-Dependent Oxygen Sensing Pathway Regulates Plant Root Hydraulics.

    Science.gov (United States)

    Shahzad, Zaigham; Canut, Matthieu; Tournaire-Roux, Colette; Martinière, Alexandre; Boursiac, Yann; Loudet, Olivier; Maurel, Christophe

    2016-09-22

    Aerobic organisms survive low oxygen (O2) through activation of diverse molecular, metabolic, and physiological responses. In most plants, root water permeability (in other words, hydraulic conductivity, Lpr) is downregulated under O2 deficiency. Here, we used a quantitative genetics approach in Arabidopsis to clone Hydraulic Conductivity of Root 1 (HCR1), a Raf-like MAPKKK that negatively controls Lpr. HCR1 accumulates and is functional under combined O2 limitation and potassium (K(+)) sufficiency. HCR1 regulates Lpr and hypoxia responsive genes, through the control of RAP2.12, a key transcriptional regulator of the core anaerobic response. A substantial variation of HCR1 in regulating Lpr is observed at the Arabidopsis species level. Thus, by combinatorially integrating two soil signals, K(+) and O2 availability, HCR1 modulates the resilience of plants to multiple flooding scenarios.

  10. Pathways to social anxiety: the role of reinforcement sensitivities and emotion regulation.

    Science.gov (United States)

    O'Connor, Elodie J; Staiger, Petra K; Kambouropoulos, Nicolas; Smillie, Luke D

    2014-12-30

    Past research has demonstrated a strong relationship between threat sensitivity and social anxiety; however, the relationship between reward sensitivity and social anxiety is less clear. Further, the role that emotion regulation (ER) may play in the expression of social anxiety disorder (SAD) is rarely considered. The current study tested whether two emotion regulation strategies (emotional suppression and cognitive reappraisal) mediated associations between threat sensitivity and reward sensitivity and social anxiety in a community sample (402 adults, 78% female; Mage=32.49, S.D.age=11.53). Path analyses indicated that low reappraisal mediated the relationship between high threat sensitivity and high social anxiety; and both low reappraisal and high suppression mediated the relationship between low reward sensitivity and high social anxiety. These results highlight the potential role that emotion regulation plays in the relationship between trait motivation and social anxiety.

  11. Transforming growth factor alpha (TGFα regulates granulosa cell tumor (GCT cell proliferation and migration through activation of multiple pathways.

    Directory of Open Access Journals (Sweden)

    Cheng Wang

    Full Text Available Granulosa cell tumors (GCTs are the most common ovarian estrogen producing tumors, leading to symptoms of excessive estrogen such as endometrial hyperplasia and endometrial adenocarcinoma. These tumors have malignant potential and often recur. The etiology of GCT is unknown. TGFα is a potent mitogen for many different cells. However, its function in GCT initiation, progression and metastasis has not been determined. The present study aims to determine whether TGFα plays a role in the growth of GCT cells. KGN cells, which are derived from an invasive GCT and have many features of normal granulosa cells, were used as the cellular model. Immunohistochemistry, Western blot and RT-PCR results showed that the ErbB family of receptors is expressed in human GCT tissues and GCT cell lines. RT-PCR results also indicated that TGFα and EGF are expressed in the human granulosa cells and the GCT cell lines, suggesting that TGFα might regulate GCT cell function in an autocrine/paracrine manner. TGFα stimulated KGN cell DNA synthesis, cell proliferation, cell viability, cell cycle progression, and cell migration. TGFα rapidly activated EGFR/PI3K/Akt and mTOR pathways, as indicated by rapid phosphorylation of Akt, TSC2, Rictor, mTOR, P70S6K and S6 proteins following TGFα treatment. TGFα also rapidly activated the EGFR/MEK/ERK pathway, and P38 MAPK pathways, as indicated by the rapid phosphorylation of EGFR, MEK, ERK1/2, P38, and CREB after TGFα treatment. Whereas TGFα triggered a transient activation of Akt, it induced a sustained activation of ERK1/2 in KGN cells. Long-term treatment of KGN cells with TGFα resulted in a significant increase in cyclin D2 and a decrease in p27/Kip1, two critical regulators of granulosa cell proliferation and granulosa cell tumorigenesis. In conclusion, TGFα, via multiple signaling pathways, regulates KGN cell proliferation and migration and may play an important role in the growth and metastasis of GCTs.

  12. The Effect of NF-κB Signalling Pathway on Expression and Regulation of Nacrein in Pearl Oyster, Pinctada fucata.

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    Juan Sun

    Full Text Available Nacrein is the first identified and widely investigated molluscan matrix protein and is considered to play an important role in the shell formation of the pearl oyster, Pinctada fucata. Here, we investigate the effect of the NF-κB signalling pathway on Nacrein gene expression in P. fucata to elucidate the mechanisms involved in shell formation. Inhibition of NF-κB signalling decreased Nacrein promoter-dependent luciferase activity. However, co-transfection of the Nacrein promoter vector with Pf-IKK or Pf-Rel expression plasmids could enhance luciferase activity, thus proving NF-κB signalling could regulate the transcriptional activity of the Nacrein promoter. Gene silencing by RNA interference and subsequent observation of the inner surface of the nacreous layer of oyster shells by SEM, showed that suppression of the gene Pf-Rel lead to a partial inhibition of Nacrein expression, not only at the mRNA level but also at the protein level. The inner surface of the shells became abnormal. Electrophoretic mobility shift assays (EMSAs revealed that Pf-Rel could directly bind to the relative sites of the Nacrein promoter. These results confirm that an important component of the NF-κB signalling pathway, Pf-Rel, can directly bind the Nacrein promoter in P. fucata, and regulate its transcription and shell formation.

  13. The Notch pathway regulates both the proliferation and differentiation of follicular cells in the panoistic ovary of Blattella germanica.

    Science.gov (United States)

    Irles, Paula; Elshaer, Nashwa; Piulachs, Maria-Dolors

    2016-01-01

    The Notch pathway is an essential regulator of cell proliferation and differentiation during development. Its involvement in insect oogenesis has been examined in insect species with meroistic ovaries, and it is known to play a fundamental role in cell fate decisions and the induction of the mitosis-to-endocycle switch in follicular cells (FCs). This work reports the functions of the main components of the Notch pathway (Notch and its ligands Delta and Serrate) during oogenesis in Blattella germanica, a phylogenetically basal species with panoistic ovary. As is revealed by RNAi-based analyses, Notch and Delta were found to contribute towards maintaining the FCs in an immature, non-apoptotic state. This ancestral function of Notch appears in opposition to the induction of transition from mitosis to endocycle that Notch exerts in Drosophila melanogaster, a change in the Notch function that might be in agreement with the evolution of the insect ovary types. Notch was also shown to play an active role in inducing ovarian follicle elongation via the regulation of the cytoskeleton. In addition, Delta and Notch interactions were seen to determine the differentiation of the posterior population of FCs. Serrate levels were found to be Notch-dependent and are involved in the control of the FC programme, although they would appear to play no crucial role in panoistic ovary oogenesis.

  14. Differential regulation of BDNF, synaptic plasticity and sprouting in the hippocampal mossy fiber pathway of male and female rats.

    Science.gov (United States)

    Scharfman, Helen E; MacLusky, Neil J

    2014-01-01

    Many studies have described potent effects of BDNF, 17β-estradiol or androgen on hippocampal synapses and their plasticity. Far less information is available about the interactions between 17β-estradiol and BDNF in hippocampus, or interactions between androgen and BDNF in hippocampus. Here we review the regulation of BDNF in the mossy fiber pathway, a critical part of hippocampal circuitry. We discuss the emerging view that 17β-estradiol upregulates mossy fiber BDNF synthesis in the adult female rat, while testosterone exerts a tonic suppression of mossy fiber BDNF levels in the adult male rat. The consequences are interesting to consider: in females, increased excitability associated with high levels of BDNF in mossy fibers could improve normal functions of area CA3, such as the ability to perform pattern completion. However, memory retrieval may lead to anxiety if stressful events are recalled. Therefore, the actions of 17β-estradiol on the mossy fiber pathway in females may provide a potential explanation for the greater incidence of anxiety-related disorders and post-traumatic stress syndrome (PTSD) in women relative to men. In males, suppression of BDNF-dependent plasticity in the mossy fibers may be protective, but at the 'price' of reduced synaptic plasticity in CA3. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.

  15. Phytochromes Regulate SA and JA Signaling Pathways in Rice and Are Required for Developmentally Controlled Resistance to Magnaporthe grisea

    Institute of Scientific and Technical Information of China (English)

    Xian-Zhi Xie; Yan-Jiu Xue; Jin-Jun Zhoua; Bin Zhang; Hong Chang; Makoto Takano

    2011-01-01

    Old leaves of wild-type rice plants (Oryza sativa L. Cv. Nipponbare)are more resistant to blast fungus (Mag-naporthe grisea)than new leaves. In contrast, both old and new leaves of the rice phytochrome triple mutant (phyAphyB-phyC)are susceptible to blast fungus. We demonstrate that pathogenesis-related class 1 (PR1)proteins are rapidly and strongly induced during M. Grisea infection and following exogenous jasmonate (JA)or salicylic acid (SA)exposure in the old leaves, but not in the new leaves of the wild-type. In contrast, the accumulation of PR1 proteins was significantly attenuated in old and new leaves of the phyAphyBphyC mutant. These results suggest that phytochromes are required for the induction of PR1 proteins in rice. Basal transcription levels of Prla and PRlb were substantially higher in the wild-type as compared to the phyAphyBphyC mutant, suggesting that phytochromes also are required for basal expression of PR1 genes. Moreover, the transcript levels of genes known to function in SA-or JA-dependent defense pathways were regulated by leaf age and functional phytochromes. Taken together, our findings demonstrate that phytochromes are required in rice for age-related resistance to M, grisea and may indirectly increase PR1 gene expression by regulating SA-and JA-dependent defense pathways.

  16. N-Acetylcysteine Prevents Hypertension via Regulation of the ADMA-DDAH Pathway in Young Spontaneously Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Nai-Chia Fan

    2013-01-01

    Full Text Available Asymmetric dimethylarginine (ADMA reduces nitric oxide (NO, thus causing hypertension. ADMA is metabolized by dimethylarginine dimethylaminohydrolase (DDAH, which can be inhibited by oxidative stress. N-Acetylcysteine (NAC, an antioxidant, can facilitate glutathione (GSH synthesis. We aimed to determine whether NAC can prevent hypertension by regulating the ADMA-DDAH pathway in spontaneously hypertensive rats (SHR. Rats aged 4 weeks were assigned into 3 groups (n=8/group: control Wistar Kyoto rats (WKY, SHR, and SHR receiving 2% NAC in drinking water. All rats were sacrificed at 12 weeks of age. SHR had higher blood pressure than WKY, whereas NAC-treated animals did not. SHR had elevated plasma ADMA levels, which was prevented by NAC therapy. SHR had lower renal DDAH activity than WKY, whereas NAC-treated animals did not. Renal superoxide production was higher in SHR than in WKY, whereas NAC therapy prevented it. NAC therapy was also associated with higher GSH-to-oxidized GSH ratio in SHR kidneys. Moreover, NAC reduced oxidative stress damage in SHR. The observed antihypertensive effects of NAC in young SHR might be due to restoration of DDAH activity to reduce ADMA, leading to attenuation of oxidative stress. Our findings highlight the impact of NAC on the development of hypertension by regulating ADMA-DDAH pathway.

  17. The gastric CB1 receptor modulates ghrelin production through the mTOR pathway to regulate food intake.

    Directory of Open Access Journals (Sweden)

    Lucia L Senin

    Full Text Available Over the years, the knowledge regarding the relevance of the cannabinoid system to the regulation of metabolism has grown steadily. A central interaction between the cannabinoid system and ghrelin has been suggested to regulate food intake. Although the stomach is the main source of ghrelin and CB1 receptor expression in the stomach has been described, little information is available regarding the possible interaction between the gastric cannabinoid and ghrelin systems in the integrated control of energy homeostasis. The main objective of the present work was to assess the functional interaction between these two systems in terms of food intake using a combination of in vivo and in vitro approaches. The present work demonstrates that the peripheral blockade of the CB1 receptor by rimonabant treatment decreased food intake but only in food-deprived animals. This anorexigenic effect is likely a consequence of decreases in gastric ghrelin secretion induced by the activation of the mTOR/S6K1 intracellular pathway in the stomach following treatment with rimonabant. In support of this supposition, animals in which the mTOR/S6K1 intracellular pathway was blocked by chronic rapamycin treatment, rimonabant had no effect on ghrelin secretion. Vagal communication may also be involved because rimonabant treatment was no longer effective when administered to animals that had undergone surgical vagotomy. In conclusion, to the best of our knowledge, the present work is the first to describe a CB1 receptor-mediated mechanism that influences gastric ghrelin secretion and food intake through the mTOR pathway.

  18. Cardiac glycoside-induced cell death and Rho/Rho kinase pathway: Implication of different regulation in cancer cell lines.

    Science.gov (United States)

    Özdemir, Aysun; Şimay, Yaprak Dilber; İbişoğlu, Burçin; Yaren, Biljana; Bülbül, Döne; Ark, Mustafa

    2016-05-01

    Previously, we demonstrated that the Rho/ROCK pathway is involved in ouabain-induced apoptosis in HUVEC. In the current work, we investigated whether the Rho/ROCK pathway is functional during cardiac glycosides-induced cytotoxic effects in cancer cell lines, as well as in non-tumor cells. For that purpose, we evaluated the role of ROCK activation in bleb formation and cell migration over upstream and downstream effectors in addition to ROCK cleavage after cardiac glycosides treatment. All three cardiac glycosides (ouabain, digoxin and bufalin) induced cell death in HeLa and HepG2 cells and increased the formation of blebbing in HeLa cells. In contrast to our previous study, ROCK inhibitor Y27632 did not prevent bleb formation. Observation of ROCK II cleavage after ouabain, digoxin and oxaliplatin treatments in HeLa and/or HepG2 cells suggested that cleavage is independent of cell type and cell death induction. While inhibiting cleavage of ROCK II by the caspase inhibitors z-VAD-fmk, z-VDVAD-fmk and z-DEVD-fmk, evaluation of caspase 2 siRNA ineffectiveness on this truncation indicated that caspase-dependent ROCK II cleavage is differentially regulated in cancer cell lines. In HeLa cells, ouabain induced the activation of ROCK, although it did not induce phosphorylation of ERM, an upstream effector. While Y27632 inhibited the migration of HeLa cells, 10nM ouabain had no effect on cell migration. In conclusion, these findings indicate that the Rho/ROCK pathway is regulated differently in cancer cell lines compared to normal cells during cardiac glycosides-induced cell death.

  19. Rho A and the Rho kinase pathway regulate fibroblast contraction: Enhanced contraction in constitutively active Rho A fibroblast cells

    Energy Technology Data Exchange (ETDEWEB)

    Nobe, Koji, E-mail: kojinobe@pharm.showa-u.ac.jp [Department of Pharmacology, School of Pharmaceutical Sciences, Showa University, Tokyo (Japan); Nobe, Hiromi [Department of Pharmacology, School of Pharmaceutical Sciences, Showa University, Tokyo (Japan); Department of Physical Therapy, Bunkyo-Gakuin University (Japan); Yoshida, Hiroko [Department of Pharmacology, School of Pharmaceutical Sciences, Showa University, Tokyo (Japan); Kolodney, Michael S. [Dermatology Division, Department of Medicine, UCLA, Los Angeles, CA (United States); Paul, Richard J. [Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH (United States); Honda, Kazuo [Department of Pharmacology, School of Pharmaceutical Sciences, Showa University, Tokyo (Japan)

    2010-08-20

    Research highlights: {yields} Mechanisms of fibroblast cell contraction in collagen matrix. {yields} Assessed an isometric force development using 3D-reconstituted-fibroblast fiber. {yields} Constitutively active Rho A induced the over-contraction of fibroblast cells. {yields} Rho A and Rho kinase pathway has a central role in fibroblast cell contraction. -- Abstract: Fibroblast cells play a central role in the proliferation phase of wound healing processes, contributing to force development. The intracellular signaling pathways regulating this non-muscle contraction are only partially understood. To study the relations between Rho A and contractile responses, constitutively active Rho A (CA-Rho A) fibroblast cells were reconstituted into fibers and the effects of calf serum (CS) on isometric force were studied. CS-induced force in CA-Rho A fibroblast fibers was twice as large as that in wild type (NIH 3T3) fibroblast fibers. During this response, the translocation of Rho A from the cytosol to the membrane was detected by Rho A activity assays and Western blot analysis. Pre-treatment with a Rho specific inhibitor (C3-exoenzyme) suppressed translocation as well as contraction. These results indicate that Rho A activation is essential for fibroblast contraction. The Rho kinase inhibitor ( (Y27632)) inhibited both NIH 3T3 and CA-Rho A fibroblast fiber contractions. Activation of Rho A is thus directly coupled with Rho kinase activity. We conclude that the translocation of Rho A from the cytosol to the membrane and the Rho kinase pathway can regulate wound healing processes mediated by fibroblast contraction.

  20. Improving the osteogenic efficacy of BMP2 with mechano growth factor by regulating the signaling events in BMP pathway.

    Science.gov (United States)

    Deng, Moyuan; Liu, Peng; Xiao, Hualiang; Zhang, Yuanyuan; Wang, Yuanliang; Zhao, Jianhua; Xu, Jianzhong

    2015-09-01

    Local application of bone morphogenetic protein 2 (BMP2) is known to promote large bone defect healing and BMP2-initiated bone regeneration could be enhanced by an additional mechanical stimulation. The C-terminal 24-a.a. peptide of mechano growth factor (MGF24E), a mechanical-sensitive molecule, has been demonstrated to promote bone healing. Here, we propose a hypothesis that MGF24E could also improve the osteogenic efficacy of BMP2 by regulating the signaling events in the BMP pathway. To confirm the hypothesis, the potentials of MGF24E, BMP2 and BMP2/MGF24E combination treatments on the phosphorylation of Smad 1/5/8, the downstream osteogenesis-related gene expression and osteoblasts mineralization, are investigated with or without the blocking of Smad 5 siRNA. Furthermore, 15-mm rabbit radial bone defects were healed with the cytokine treatments and then evaluated by radiographic examination, histological assessment and immunohistochemical analysis. MGF24E could enhance the BMP2-induced Smad signaling pathway by upregulating the p-Smad protein expression and the downstream osteogenic gene expression. An amount of 5 nM BMP2 in a sub-25 nM concentration of MGF24E medium achieved a higher expression for ALP mRNA and a greater calcium mineral content compared with BMP2 alone. Nevertheless, the inhibition of the MGF24E-regulated BMP pathway could block osteogenesis induced by the dual treatment. In vivo, MGF24E treatment upregulated the endogenous BMP2 expression and the addition of MGF24E into the BMP2 treatment remarkably enhanced the bone mineral density (BMD), the radiographic scores and the histological restoration of the regenerated tissue against BMP2 treatment, suggesting a new strategy for BMP2 in bone defect healing.

  1. DMPD: HIV-1 infection and regulation of Tat function in macrophages. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available ication Int J Biochem Cell Biol. 2004 Sep;36(9):1767-75. Pathway - PNG File (.png) SVG File (.svg) HTML File (.html) CSML File (.csm...rrmann CH, Rice AP. Int J Biochem Cell Biol. 2004 Sep;36(9):1767-75. (.png) (.svg) (.html) (.csml) Show HIV-...l) Open .csml file with CIOPlayer Open .csml file with CIOPlayer - ※CIO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ...

  2. DMPD: New insights into NF-kappaB regulation and function. [Dynamic Macrophage Pathway CSML Database

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    Full Text Available 2008 Sep 3. Pathway - PNG File (.png) SVG File (.svg) HTML File (.html) CSML File (.csml) Open .csml file with CIOPlayer Open .csm...s Immunol. 2008 Oct;29(10):469-78. Epub 2008 Sep 3. (.png) (.svg) (.html) (.csml) Show New insights into NF-...l file with CIOPlayer - ※CIO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ...

  3. DMPD: New insights into the regulation of TLR signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available pub 2006 May 12. Pathway - PNG File (.png) SVG File (.svg) HTML File (.html) CSML File (.csml) Open .csml fi...J Leukoc Biol. 2006 Aug;80(2):220-6. Epub 2006 May 12. (.png) (.svg) (.html) (.csml) Show New insights into ...le with CIOPlayer Open .csml file with CIOPlayer - ※CIO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ...

  4. Peroxiredoxins in Regulation of MAPK Signalling Pathways; Sensors and Barriers to Signal Transduction

    Science.gov (United States)

    Latimer, Heather R.; Veal, Elizabeth A.

    2016-01-01

    Peroxiredoxins are highly conserved and abundant peroxidases. Although the thioredoxin peroxidase activity of peroxiredoxin (Prx) is important to maintain low levels of endogenous hydrogen peroxide, Prx have also been shown to promote hydrogen peroxide-mediated signalling. Mitogen activated protein kinase (MAPK) signalling pathways mediate cellular responses to a variety of stimuli, including reactive oxygen species (ROS). Here we review the evidence that Prx can act as both sensors and barriers to the activation of MAPK and discuss the underlying mechanisms involved, focusing in particular on the relationship with thioredoxin. PMID:26813660

  5. Epigenetic Regulation of the ERβ Gene on the Estrogen Signal Transfection Pathway in Colon Cancer Cells

    Institute of Scientific and Technical Information of China (English)

    翟荣林; 王国斌; 蔡开琳; 陶凯雄; 许飞; 张万里; 王智勇

    2010-01-01

    We studied the regulatory effects of the estragen receptorβ(ERβ)gene on the downstream estrogen signal transfection pathway in colon cancer cells and the possible mechanisms involved.A human ERβ gene recombinant expression plasmid,pEGFP-C1-ERβ,was constructed and transfected into the Caco-2 colon cancer cell line,a line with low ERβ gene expression.The expression of ERβ mRNA and protein was detected 72h after transfection.RT-PCR was used to examine the expression levels of the progesterone recepror(PR)gene ...

  6. Livin abrogates apoptosis of SPC-A1 cell by regulating JNKI signaling pathway.

    Science.gov (United States)

    Chen, Yu-Sheng; Li, Hong-Ru; Lin, Ming; Chen, Gang; Xie, Bao-Song; Xu, Neng-Luan; Lin, Li-Fang

    2010-06-01

    Livin, a novel member of inhibitors of apoptosis protein, is highly expressed in tumor tissues. It is a potential target in tumor therapy. Silencing its gene expression has been found to promote tumor cell apoptosis or increase tumor sensitivity to therapies. This paper studied the effect of livin anti-apoptotic activity and examined its molecular mechanisms. In the study, higher levels of cell apoptosis were measured by FACS in the experiment group with livin expression silenced than that in controls (P SPC-A1 by activating JNK1 signaling pathway and inhibiting caspase-3 activation.

  7. A control study to evaluate a computer-based microarray experiment design recommendation system for gene-regulation pathways discovery.

    Science.gov (United States)

    Yoo, Changwon; Cooper, Gregory F; Schmidt, Martin

    2006-04-01

    The main topic of this paper is evaluating a system that uses the expected value of experimentation for discovering causal pathways in gene expression data. By experimentation we mean both interventions (e.g., a gene knock-out experiment) and observations (e.g., passively observing the expression level of a "wild-type" gene). We introduce a system called GEEVE (causal discovery in Gene Expression data using Expected Value of Experimentation), which implements expected value of experimentation in discovering causal pathways using gene expression data. GEEVE provides the following assistance, which is intended to help biologists in their quest to discover gene-regulation pathways: Recommending which experiments to perform (with a focus on "knock-out" experiments) using an expected value of experimentation (EVE) method. Recommending the number of measurements (observational and experimental) to include in the experimental design, again using an EVE method. Providing a Bayesian analysis that combines prior knowledge with the results of recent microarray experimental results to derive posterior probabilities of gene regulation relationships. In recommending which experiments to perform (and how many times to repeat them) the EVE approach considers the biologist's preferences for which genes to focus the discovery process. Also, since exact EVE calculations are exponential in time, GEEVE incorporates approximation methods. GEEVE is able to combine data from knock-out experiments with data from wild-type experiments to suggest additional experiments to perform and then to analyze the results of those microarray experimental results. It models the possibility that unmeasured (latent) variables may be responsible for some of the statistical associations among the expression levels of the genes under study. To evaluate the GEEVE system, we used a gene expression simulator to generate data from specified models of gene regulation. Using the simulator, we evaluated the GEEVE

  8. Defense mechanisms against herbivory in Picea: sequence evolution and expression regulation of gene family members in the phenylpropanoid pathway

    Directory of Open Access Journals (Sweden)

    Porth Ilga

    2011-12-01

    Full Text Available Abstract Background In trees, a substantial amount of carbon is directed towards production of phenolics for development and defense. This metabolic pathway is also a major factor in resistance to insect pathogens in spruce. In such gene families, environmental stimuli may have an important effect on the evolutionary fate of duplicated genes, and different expression patterns may indicate functional diversification. Results Gene families in spruce (Picea have expanded to superfamilies, including O-methyltransferases, cytochrome-P450, and dirigents/classIII-peroxidases. Neo-functionalization of superfamily members from different clades is reflected in expression diversification. Genetical genomics can provide new insights into the genetic basis and evolution of insect resistance in plants. Adopting this approach, we merged genotype data (252 SNPs in a segregating pedigree, gene expression levels (for 428 phenylpropanoid-related genes and measures of susceptibility to Pissodes stobi, using a partial-diallel crossing-design with white spruce (Picea glauca. Thirty-eight expressed phenylpropanoid-related genes co-segregated with weevil susceptibility, indicating either causative or reactive effects of these genes to weevil resistance. We identified eight regulatory genomic regions with extensive overlap of quantitative trait loci from susceptibility and growth phenotypes (pQTLs and expression QTL (eQTL hotspots. In particular, SNPs within two different CCoAOMT loci regulate phenotypic variation from a common set of 24 genes and three resistance traits. Conclusions Pest resistance was associated with individual candidate genes as well as with trans-regulatory hotspots along the spruce genome. Our results showed that specific genes within the phenylpropanoid pathway have been duplicated and diversified in the conifer in a process fundamentally different from short-lived angiosperm species. These findings add to the information about the role of the

  9. Differential regulation of atrial natriuretic peptide- and adrenergic receptor-dependent lipolytic pathways in human adipose tissue.

    Science.gov (United States)

    Moro, Cédric; Polak, Jan; Richterova, Blanka; Sengenès, Coralie; Pelikanova, Terezie; Galitzky, Jean; Stich, Vladimir; Lafontan, Max; Berlan, Michel

    2005-01-01

    The aim of the study was to investigate the regulation affecting the recently described atrial natriuretic peptide (ANP)-dependent lipolytic pathway in comparison with the adrenergic lipolytic cascade. We studied in vivo the effect of a euglycemic-hyperinsulinemic clamp on the changes occurring in the extracellular glycerol concentration (EGC) of subcutaneous adipose tissue (SCAT) during ANP or epinephrine perfusion in a microdialysis probe. Homologous desensitization and the incidence of hyperinsulinemia on the ANP- and catecholaminergic-dependent control of lipolysis were also investigated in vitro on fat cells from SCAT. When perfused in SCAT, epinephrine and ANP promoted an increase in EGC; the EGC increase was significantly lower during the clamp. The reduction of epinephrine-induced lipolysis was limited (18%) when phentolamine (an alpha(2)-adrenergic receptor [AR] antagonist) was perfused together with epinephrine. Unlike the effect of epinephrine, the response to ANP observed during the second perfusion was reduced by 32%. The increase in extracellular guanosine 3',5' -cyclic monophosphate concentration, which reflects ANP activity, was also reduced during the second perfusion. Desensitization of the lipolytic effects of ANP was observed in vitro after a 2-hour period of recovery, while the effects of alpha(2)-AR agonist or of epinephrine were unchanged. Insulin was without any effect on ANP-induced lipolysis and alpha(2)-AR-mediated antilipolysis, while it reduced beta-AR-induced lipolysis. The ANP-dependent lipolytic pathway undergoes desensitization in vitro and in situ. Insulin had no inhibitory effect on either ANP- or alpha(2)-AR-dependent pathways, while it counteracted the beta-AR pathway.

  10. PHLDA1 Promotes Lung Contusion by Regulating the Toll-Like Receptor 2 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Shaohua Wang

    2016-12-01

    Full Text Available Background/Aims: Lung contusion is a potentially lethal injury. Pleckstrin homology-like domain family A, member-1 (PHLDA1 is known to play crucial roles in cell proliferation and apoptosis. In this study, we investigated the biological role of PHLDA1 in lung contusion. Methods: The expression levels of PHLDA1 and TLR2 were detected by real time PCR and western. The cytokines were determined by ELISA. The inflammatory factors were detected by flow cytometry. The lung injury was determined by HE staining. Results: PHLDA1 gene and protein expression levels were up-regulated in a mouse lung-contusion model, together with increased neutrophil and macrophage contents. Down-regulation of PHLDA1 by interfering RNA (siPHLDA1 mice decreased lung injury and neutrophil infiltration. Inflammatory factors, including interleukin (IL-1β, IL-6, mouse homolog of human growth-regulated oncogene-α (KC, tumor necrosis factor-α, CC chemokine ligand (CCL 2, and CCL12 were also decreased in siPHLDA1 mice. Expression levels of Toll-like receptor 2 (TLR2 were increased in the lung-contusion mouse model, but were decreased when PHLDA1 was down-regulated. Conclusion: These results demonstrate that PHLDA1 plays a critical role in the development of progressive lung contusion and subsequent inflammation. This information furthers our understanding of the pathogenesis of lung contusion, and suggests that PHLDA1 blockade may represent a potential therapeutic strategy for the treatment of this injury.

  11. Multiple pathways for steel regulation suggested by genomic and sequence analysis of the murine Steel gene

    Energy Technology Data Exchange (ETDEWEB)

    Bedell, M.A.; Copeland, N.G.; Jenkins, N.A. [NCI-Frederick Cancer Research and Development Center, Frederick, MD (United States)

    1996-03-01

    The Steel (Sl) locus encodes mast cell growth factor (Mgf) that is required for the development of germ cells, hematopoietic cells and melanocytes. Although the expression patterns of the Mgf gene are well characterized, little is known of the factors which regulate its expression. Here, we describe the cloning and sequence of the full-length transcription unit and the 5{prime} flanking region of the murine Mgf gene. The full-length Mgf mRNA consists of a short 5{prime} untranslated region (UTR), a 0.8-kb ORF and a long 3{prime} UTR. A single transcription initiation site is used in a number of mouse tissues and is located just downstream of binding sites for several known transcription factors. In the 5{prime} UTR, two ATGs were found upstream of the initiator methionine and are conserved among different species, suggesting that Mgf may be translationally regulated. At least two Mgf mRNAs are produced by alternative use of polyadenylation sites, but numerous other potential polyadenylation sites were found in the 3{prime} UTR. In addition, the 3{prime} UTR contains numerous sequence motifs that may regulate Mgf mRNA stability. These studies suggest multiple ways in which expression of Mgf may be regulated. 39 refs., 4 figs.

  12. Trefoil factor 3 peptide regulates migration via a Twist-dependent pathway in gastric cell.

    Science.gov (United States)

    Zheng, Qianqian; Gao, Jian; Li, Honglin; Guo, Wendong; Mao, Qi; Gao, Enhui; Zhu, Ya-qin

    2013-08-16

    Trefoil factor 3 (TFF3) is a member of the TFF-domain peptide family and essential in regulating cell migration and maintaining mucosal integrity in gastrointestinal tract. However, the role of TFF3 and its downstream regulating mechanisms in cancer cell migration remain unclear. We previously reported that TFF3 prolonged the up-regulation of Twist protein to modulate IL-8 secretion in intestinal epithelial cells. In this study, we investigated the role of Twist protein in TFF3-induced migration of SGC7901 cells. While Twist was activated by TFF3, siRNA-mediated knockdown of Twist abolished TFF3-induced cell migration. Furthermore, the migration related marker CK-8 as well as ZO-1 and MMP-9 was also regulated by TFF3 via a Twist-dependent mechanism. Our study suggests that Twist, as an important potential downstream effector, plays a key role in TFF3-modulated metastasis in gastric cancer and can be a promising therapeutic target against intestinal-type gastric cancer.

  13. SIRT1 regulates accumulation of oxidized LDL in HUVEC via the autophagy-lysosomal pathway.

    Science.gov (United States)

    Zhang, Yanlin; Sun, Juanjuan; Yu, Xiaoyan; Shi, Luyao; Du, Wenxiu; Hu, Lifang; Liu, Chunfeng; Cao, Yongjun

    2016-01-01

    Autophagy is involved in the degradation of oxidized low-density lipoprotein (ox-LDL) in human umbilical vein endothelial cells (HUVECs). Sirtuin1 (SIRT1), a new anti-atherosclerotic factor, can induce autophagy in cardiac myocytes. In the present study, we observed the effect of SIRT1 on the accumulation of ox-LDL in HUVECs, and elucidated whether its effect is relative with the autophagy-lysosomal pathway. The results showed that treatment with either SIRT1 siRNA or SIRT1 inhibitor nicotinamide (NAM) increased Dil-labelled-ox-LDL (Dil-ox-LDL) accumulation in HUVECs, and the SIRT1 inducer resveratrol (RSV) decreased it. Knockdown of autophagy-related protein 5 or inhibit the lysosomal degradation by chloroquine (CQ) decreased the effect of RSV. In HUVECs with ox-LDL, expression of LC3II and LC3 puncta was decreased by treatment with SIRT1 siRNA or NAM, but increased by RSV treatment; sequestosome 1 p62 expression showed the opposite effects. Moreover, Dil-ox-LDL combined with SIRT1 siRNA or NAM showed a much smaller degree of overlap of Lamp1 or Cathepsin D with Dil-ox-LDL than in cells with Dil-ox-LDL alone, and RSV treatment resulted in a greater degree of overlap. These results suggest that SIRT1 can decrease the accumulation of ox-LDL in HUVECs, and this effect is related to the autophagy-lysosomal pathway.

  14. Nuclear magnetic resonance studies of the regulation of the pentose phosphate pathway

    Energy Technology Data Exchange (ETDEWEB)

    Bolo, N.R.

    1991-11-01

    The goal of this work is to investigate the potential for and limitations of in vivo nuclear magnetic resonance (NMR) spectroscopy for quantitation of glucose flux through the pentose phosphate pathway (shunt). Interest in the shunt is motivated by the possibility that its activity may be greatly increased in cancer and in the pathological states of cardiac and cerebral ischemia. The ability to dynamically monitor flux through the pentose shunt can give new knowledge about metabolism in pathological states. {sup 13}C NMR spectroscopy was used to monitor shunt activity by determination of the ratios of ({sup 13}C-4) to ({sup 13}C-5)-glutamate, ({sup 13}C-3) to ({sup 13}C-2)-alanine or ({sup 13}C-3) to ({sup 13}C-2)-lactate produced when ({sup 13}C-2)-glucose is infused. These methods provide measures of the effect of oxidative stresses on shunt activity in systems ranging from cell free enzyme-substrate preparations to cell suspensions and whole animals. In anaerobic cell free preparations, the fraction of glucose flux through the shunt was monitored with a time resolution of 3 minutes. This work predicts the potential for in vivo human studies of pentose phosphate pathway activity based on the mathematical simulation of the {sup 13}C fractional enrichments of C4 and C5-glutamate as a function of shunt activity and on the signal-to- noise ratio acquired in {sup 13}C NMR human studies from the current literature.

  15. Nuclear magnetic resonance studies of the regulation of the pentose phosphate pathway

    Energy Technology Data Exchange (ETDEWEB)

    Bolo, N.R.

    1991-11-01

    The goal of this work is to investigate the potential for and limitations of in vivo nuclear magnetic resonance (NMR) spectroscopy for quantitation of glucose flux through the pentose phosphate pathway (shunt). Interest in the shunt is motivated by the possibility that its activity may be greatly increased in cancer and in the pathological states of cardiac and cerebral ischemia. The ability to dynamically monitor flux through the pentose shunt can give new knowledge about metabolism in pathological states. {sup 13}C NMR spectroscopy was used to monitor shunt activity by determination of the ratios of [{sup 13}C-4] to [{sup 13}C-5]-glutamate, [{sup 13}C-3] to [{sup 13}C-2]-alanine or [{sup 13}C-3] to [{sup 13}C-2]-lactate produced when [{sup 13}C-2]-glucose is infused. These methods provide measures of the effect of oxidative stresses on shunt activity in systems ranging from cell free enzyme-substrate preparations to cell suspensions and whole animals. In anaerobic cell free preparations, the fraction of glucose flux through the shunt was monitored with a time resolution of 3 minutes. This work predicts the potential for in vivo human studies of pentose phosphate pathway activity based on the mathematical simulation of the {sup 13}C fractional enrichments of C4 and C5-glutamate as a function of shunt activity and on the signal-to- noise ratio acquired in {sup 13}C NMR human studies from the current literature.

  16. Study of chromosome 9q gain, Notch pathway regulators and Tenascin-C in ependymomas.

    Science.gov (United States)

    Gupta, Rakesh Kumar; Sharma, Mehar C; Suri, Vaishali; Kakkar, Aanchal; Singh, Manmohan; Sarkar, Chitra

    2014-01-01

    Ependymomas are relatively uncommon tumours of the central nervous system which arise from the ependymal lining of the ventricles and spinal canal. The molecular changes leading to ependymal oncogenesis are not completely understood. We examined chromosome 9q33-34 locus for gain, potential oncogenes at this locus (Notch-1 and Tenascin-C) and Notch pathway target genes (Hes-1, Hey-2 & C-myc) in ependymomas by fluorescent in situ hybridization (FISH) and immunohistochemistry (IHC), respectively, to assess if they have any correlation with clinical characteristics. We analyzed 50 cases of ependymomas by FISH for 9q gain and by IHC for Notch-1 and its target gene proteins (Hes-1, Hey-2 and C-myc) expression. We also performed IHC for Tenascin-C to rule out any correlation with aggressiveness/grade of tumour. FISH study revealed significant chromosome 9q gain in ependymomas of adult onset (age > 18 years) and spinal cord origin. Notch-1 showed significantly more frequent immunohistochemical expression in supratentorial and anaplastic ependymomas. Tenascin-C (TN-C) expression was significant in intracranial, childhood (age ≤ 18 years) and anaplastic ependymomas. Of the three Notch pathway target gene proteins (Hes-1, Hey-2 and C-myc), Hes-1 and C-myc expression showed significant correlation with anaplastic and adult onset ependymomas, respectively. Genetic alterations are independent prognostic markers in ependymomas. A clinicopathological correlation with various molecular signatures may be helpful in the development of new therapeutic targets.

  17. Neurobeachin Regulates Glutamate- and GABA-Receptor Targeting to Synapses via Distinct Pathways.

    Science.gov (United States)

    Farzana, F; Zalm, R; Chen, N; Li, K W; Grant, Seth G N; Smit, A B; Toonen, R F; Verhage, M

    2016-05-01

    Neurotransmission and synaptic strength depend on expression of post-synaptic receptors on the cell surface. Post-translational modification of receptors, trafficking to the synapse through the secretory pathway, and subsequent insertion into the synapse involves interaction of the receptor with A-kinase anchor proteins (AKAPs) and scaffolding proteins. Neurobeachin (Nbea), a brain specific AKAP, is required for synaptic surface expression of both glutamate and GABA receptors. Here, we investigated the role of Nbea-dependent targeting of postsynaptic receptors by studying Nbea interaction with synapse-associated protein 102 (SAP102/Dlg3) and protein kinase A subunit II (PKA II). A Nbea mutant lacking the PKA binding domain showed a similar distribution as wild-type Nbea in Nbea null neurons and partially restored GABA receptor surface expression. To understand the relevance of Nbea interaction with SAP102, we analysed SAP102 null mutant mice. Nbea levels were reduced by ~80% in SAP102 null mice, but glutamatergic receptor expression was normal. A single-point mutation in the pleckstrin homology domain of Nbea (E2218R) resulted in loss of binding with SAP102. When expressed in Nbea null neurons, this mutant fully restored GABA receptor surface expression, but not glutamate receptor expression. Our results suggest that the PKA-binding domain is not essential for Nbea's role in receptor targeting and that Nbea targets glutamate and GABA receptors to the synapse via distinct molecular pathways by interacting with specific effector proteins.

  18. KAP regulates ROCK2 and Cdk2 in an RNA-activated glioblastoma invasion pathway.

    Science.gov (United States)

    Li, H; Jiang, X; Yu, Y; Huang, W; Xing, H; Agar, N Y; Yang, H W; Yang, B; Carroll, R S; Johnson, M D

    2015-03-12

    Aberrant splicing of the cyclin-dependent kinase-associated phosphatase, KAP, promotes glioblastoma invasion in a Cdc2-dependent manner. However, the mechanism by which this occurs is unknown. Here we show that miR-26a, which is often amplified in glioblastoma, promotes invasion in phosphatase and tensin homolog (PTEN)-competent and PTEN-deficient glioblastoma cells by directly downregulating KAP expression. Mechanistically, we find that KAP binds and activates ROCK2. Thus, RNA-mediated downregulation of KAP leads to decreased ROCK2 activity and this, in turn, increases Rac1-mediated invasion. In addition, the decrease in KAP expression activates the cyclin-dependent kinase, Cdk2, and this directly promotes invasion by increasing retinoblastoma phosphorylation, E2F-dependent Cdc2 expression and Cdc2-mediated inactivation of the actomyosin inhibitor, caldesmon. Importantly, glioblastoma cell invasion mediated by this pathway can be antagonized by Cdk2/Cdc2 inhibitors in vitro and in vivo. Thus, two distinct RNA-based mechanisms activate this novel KAP/ROCK2/Cdk2-dependent invasion pathway in glioblastoma.

  19. The balance of powers: Redox regulation of fibrogenic pathways in kidney injury.

    Science.gov (United States)

    Okamura, Daryl M; Pennathur, Subramaniam

    2015-12-01

    Oxidative stress plays a central role in the pathogenesis of diverse chronic inflammatory disorders including diabetic complications, cardiovascular disease, aging, and chronic kidney disease (CKD). Patients with moderate to advanced CKD have markedly increased levels of oxidative stress and inflammation that likely contribute to the unacceptable high rates of morbidity and mortality in this patient population. Oxidative stress is defined as an imbalance of the generation of reactive oxygen species (ROS) in excess of the capacity of cells/tissues to detoxify or scavenge them. Such a state of oxidative stress may alter the structure/function of cellular macromolecules and tissues that eventually leads to organ dysfunction. The harmful effects of ROS have been largely attributed to its indiscriminate, stochastic effects on the oxidation of protein, lipids, or DNA but in many instances the oxidants target particular amino acid residues or lipid moieties. Oxidant mechanisms are intimately involved in cell signaling and are linked to several key redox-sensitive signaling pathways in fibrogenesis. Dysregulation of antioxidant mechanisms and overproduction of ROS not only promotes a fibrotic milieu but leads to mitochondrial dysfunction and further exacerbates kidney injury. Our studies support the hypothesis that unique reactive intermediates generated in localized microenvironments of vulnerable tissues such as the kidney activate fibrogenic pathways and promote end-organ damage. The ability to quantify these changes and assess response to therapies will be pivotal in understanding disease mechanisms and monitoring efficacy of therapy.

  20. Regulation of airway inflammation and remodeling in asthmatic mice by TLR3/TRIF signal pathway.

    Science.gov (United States)

    Yang, Mei; Wang, Hao-Ying; Chen, Jian-Chang; Zhao, Jing

    2017-03-23

    This paper aims to investigate the effect of Toll-like receptors 3 (TLR3)/TIR-domain-containing adapter-inducing interferon-β (TRIF) signal pathway on the airway inflammation and remodeling in asthmatic mice. C57BL/6 and TLR3(-/-) mice were randomly divided into three groups (10 mice per group), including Control group (mice inhaled phosphate buffer saline (PBS)), Asthma group (mice inhaled ovalbumin (OVA)) and polyriboinosinic-ribocytidylic acid (poly (I: C)) group (asthmatic mice were injected intraperitoneally with TLR3 agonist poly (I: C)). Hematoxylin-eosin (HE) staining, Wright-Giemsa staining, Enzyme-linked immunosorbent assay (ELISA), Immunohistochemistry, Hydroxyproline assay, quantitative real time polymerase chain reaction (qRT-PCR) and Western blot were used to assess for the indices of airway inflammation and remodeling. In terms of WT mice, all asthma groups with or without the addition of poly (I: C) showed exaggerated inflammation and remodeling in the airways as compared to Control group, which were more seriously in poly (I: C) group than Asthma group. Furthermore, we observed the significant inhibition of airway inflammation and remodeling in the TLR3(-/-) mice in both Asthma no matter with or without addition of poly (I: C) than the WT mice. TLR3 knockout could obviously relieve the airway inflammation and remodeling in asthma through inhibiting TLR3/TRIF signaling pathway.

  1. Metabolite and light regulation of metabolism in plants: lessons from the study of a single biochemical pathway

    Directory of Open Access Journals (Sweden)

    I.C. Oliveira

    2001-05-01

    Full Text Available We are using molecular, biochemical, and genetic approaches to study the structural and regulatory genes controlling the assimilation of inorganic nitrogen into the amino acids glutamine, glutamate, aspartate and asparagine. These amino acids serve as the principal nitrogen-transport amino acids in most crop and higher plants including Arabidopsis thaliana. We have begun to investigate the regulatory mechanisms controlling nitrogen assimilation into these amino acids in plants using molecular and genetic approaches in Arabidopsis. The synthesis of the amide amino acids glutamine and asparagine is subject to tight regulation in response to environmental factors such as light and to metabolic factors such as sucrose and amino acids. For instance, light induces the expression of glutamine synthetase (GLN2 and represses expression of asparagine synthetase (ASN1 genes. This reciprocal regulation of GLN2 and ASN1 genes by light is reflected at the level of transcription and at the level of glutamine and asparagine biosynthesis. Moreover, we have shown that the regulation of these genes is also reciprocally controlled by both organic nitrogen and carbon metabolites. We have recently used a reverse genetic approach to study putative components of such metabolic sensing mechanisms in plants that may be conserved in evolution. These components include an Arabidopsis homolog for a glutamate receptor gene originally found in animal systems and a plant PII gene, which is a homolog of a component of the bacterial Ntr system. Based on our observations on the biology of both structural and regulatory genes of the nitrogen assimilatory pathway, we have developed a model for metabolic control of the genes involved in the nitrogen assimilatory pathway in plants.

  2. The ERECTA, CLAVATA and class III HD-ZIP Pathways Display Synergistic Interactions in Regulating Floral Meristem Activities.

    Directory of Open Access Journals (Sweden)

    Udi Landau

    Full Text Available In angiosperms, the production of flowers marks the beginning of the reproductive phase. At the emergence of flower primordia on the flanks of the inflorescence meristem, the WUSCHEL (WUS gene, which encodes a homeodomain transcription factor starts to be expressed and establishes de novo stem cell population, founder of the floral meristem (FM. Similarly to the shoot apical meristem a precise spatial and temporal expression pattern of WUS is required and maintained through strict regulation by multiple regulatory inputs to maintain stem cell homeostasis. However, following the formation of a genetically determined fixed number of floral organs, this homeostasis is shifted towards organogenesis and the FM is terminated. In here we performed a genetic study to test how a reduction in ERECTA, CLAVATA and class III HD-ZIP pathways affects floral meristem activity and flower development. We revealed strong synergistic phenotypes of extra flower number, supernumerary whorls, total loss of determinacy and extreme enlargement of the meristem as compared to any double mutant combination indicating that the three pathways, CLV3, ER and HD-ZIPIII distinctively regulate meristem activity and that they act in parallel. Our findings yield several new insights into stem cell-driven development. We demonstrate the crucial requirement for coupling floral meristem termination with carpel formation to ensure successful reproduction in plants. We also show how regulation of meristem size and alternation in spatial structure of the meristem serve as a mechanism to determine flower organogenesis. We propose that the loss of FM determinacy due to the reduction in CLV3, ER and HD-ZIPIII activity is genetically separable from the AGAMOUS core mechanism of meristem termination.

  3. Saikosaponin D acts against corticosterone-induced apoptosis via regulation of mitochondrial GR translocation and a GR-dependent pathway.

    Science.gov (United States)

    Li, Zong-Yang; Jiang, Yu-Mao; Liu, Ya-Min; Guo, Zhi; Shen, Sheng-Nan; Liu, Xin-Min; Pan, Rui-Le

    2014-08-04

    Saikosaponin D is an agonist of the glucocorticoid receptor (GR), and our preliminary study showed that it possesses neuroprotective effects in corticosterone-treated PC12 cells. However, further proof is required, and the molecular mechanisms of this neuroprotection remain unclear. This study sought to further examine the cytoprotective efficiency and potential mechanisms of action of Saikosaponin D in corticosterone-treated PC12 cells. The cells were treated with 250 μM corticosterone in the absence or presence of Saikosaponin D for 24 h; cell viability was then determined, and Hoechst 33342/propidium iodide (PI) and annexin/PI double staining, and TUNEL staining were performed. Next, mPTP, MMP, [Ca(2+)]i, translocation of the GR to the nucleus and Western blot analyses for caspase-3, caspase-9, cytochrome C, GR, GILZ, SGK-1, NF-Κb (P65), IκB-α, Bad, Akt, Hsp90 and HDAC-6 were investigated. The neuroprotective effects of Saikosaponin D were further confirmed by Hoechst 33342/PI, annexin/PI and TUNEL staining assays. These additional data suggested that Saikosaponin D partially reversed the physiological changes induced by corticosterone by inhibiting the translocation of the GR to the mitochondria, restoring mitochondrial function, down-regulating the expression of pro-apoptotic-related signalling events and up-regulating anti-apoptotic-related signalling events. These findings suggest that SSD exhibited its anti-apoptotic effects via differential regulation of mitochondrial and nuclear GR translocation, partial reversal of mitochondrial dysfunction, inhibition of the mitochondrial apoptotic pathway, and selective activation of the GR-dependent survival pathway.

  4. The ERECTA, CLAVATA and class III HD-ZIP Pathways Display Synergistic Interactions in Regulating Floral Meristem Activities

    Science.gov (United States)

    Landau, Udi; Asis, Lior; Eshed Williams, Leor

    2015-01-01

    In angiosperms, the production of flowers marks the beginning of the reproductive phase. At the emergence of flower primordia on the flanks of the inflorescence meristem, the WUSCHEL (WUS) gene, which encodes a homeodomain transcription factor starts to be expressed and establishes de novo stem cell population, founder of the floral meristem (FM). Similarly to the shoot apical meristem a precise spatial and temporal expression pattern of WUS is required and maintained through strict regulation by multiple regulatory inputs to maintain stem cell homeostasis. However, following the formation of a genetically determined fixed number of floral organs, this homeostasis is shifted towards organogenesis and the FM is terminated. In here we performed a genetic study to test how a reduction in ERECTA, CLAVATA and class III HD-ZIP pathways affects floral meristem activity and flower development. We revealed strong synergistic phenotypes of extra flower number, supernumerary whorls, total loss of determinacy and extreme enlargement of the meristem as compared to any double mutant combination indicating that the three pathways, CLV3, ER and HD-ZIPIII distinctively regulate meristem activity and that they act in parallel. Our findings yield several new insights into stem cell-driven development. We demonstrate the crucial requirement for coupling floral meristem termination with carpel formation to ensure successful reproduction in plants. We also show how regulation of meristem size and alternation in spatial structure of the meristem serve as a mechanism to determine flower organogenesis. We propose that the loss of FM determinacy due to the reduction in CLV3, ER and HD-ZIPIII activity is genetically separable from the AGAMOUS core mechanism of meristem termination. PMID:25946150

  5. Regulation of HTLV-1 tax stability, cellular trafficking and NF-κB activation by the ubiquitin-proteasome pathway.

    Science.gov (United States)

    Lavorgna, Alfonso; Harhaj, Edward William

    2014-10-23

    Human T-cell leukemia virus type 1 (HTLV-1) is a complex retrovirus that infects CD4+ T cells and causes adult T-cell leukemia/lymphoma (ATLL) in 3%-5% of infected individuals after a long latent period. HTLV-1 Tax is a trans-activating protein that regulates viral gene expression and also modulates cellular signaling pathways to enhance T-cell proliferation and cell survival. The Tax oncoprotein promotes T-cell transformation, in part via constitutive activation of the NF-κB transcription factor; however, the underlying mechanisms remain unknown. Ubiquitination is a type of post-translational modification that occurs in a three-step enzymatic cascade mediated by E1, E2 and E3 enzymes and regulates protein stability as well as signal transduction, protein trafficking and the DNA damage response. Emerging studies indicate that Tax hijacks the ubiquitin machinery to activate ubiquitin-dependent kinases and downstream NF-κB signaling. Tax interacts with the E2 conjugating enzyme Ubc13 and is conjugated on C-terminal lysine residues with lysine 63-linked polyubiquitin chains. Tax K63-linked polyubiquitination may serve as a platform for signaling complexes since this modification is critical for interactions with NEMO and IKK. In addition to NF-κB signaling, mono- and polyubiquitination of Tax also regulate its subcellular trafficking and stability. Here, we review recent advances in the diverse roles of ubiquitin in Tax function and how Tax usurps the ubiquitin-proteasome pathway to promote oncogenesis.

  6. Sulforaphane reverses glucocorticoid-induced apoptosis in osteoblastic cells through regulation of the Nrf2 pathway

    Directory of Open Access Journals (Sweden)

    Lin H

    2014-07-01

    Full Text Available Hao Lin,1,* Bo Wei,1,* Guangsheng Li,1 Jinchang Zheng,1 Jiecong Sun,1 Jiaqi Chu,2 Rong Zeng,1 Yanru Niu21Department of Spinal Surgery, Affiliated Hospital of Guangdong Medical College, Zhanjiang, People’s Republic of China; 2Laboratory Institute of Minimally Invasive Orthopedic Surgery, Affiliated Hospital of Guangdong Medical College, Zhanjiang, People’s Republic of China *These authors contributed equally to this work Abstract: Apoptosis of osteoblasts triggered by high-dose glucocorticoids (GCs has been identified as a major cause of osteoporosis. However, the underlying molecular mechanisms accounting for this action remain elusive, which has impeded the prevention and cure of this side effect. Sulforaphane (SFP is a naturally occurring isothiocyanate that has huge health benefits for humans. In this study, by using osteoblastic MC3T3-E1 cells as a model, we demonstrate the protective effects of SFP against dexamethasone (Dex-induced apoptosis and elucidate the underlying molecular mechanisms. The results show that SFP could effectively inhibit the Dex-induced growth inhibition and release of lactate dehydrogenase in MC3T3-E1 cells. Treatment with Dex induced caspase-dependent apoptosis in MC3T3-E1 cells, as evidenced by an increase in the Sub-G1 phase, chromatin condensation, and deoxyribonucleic acid fragmentation, which were significantly suppressed by coincubation with SFP. Mitochondria-mediated apoptosis pathway contributed importantly to Dex-induced apoptosis, as revealed by the activation of caspase-3/-9 and subsequent cleavage of poly adenosine diphosphate ribose polymerase, which was also effectively blocked by SFP. Moreover, treatments of Dex strongly induced overproduction of reactive oxygen species and inhibited the expression of nuclear factor erythroid 2-related factor 2 (Nrf2 and the downstream effectors HO1 and NQO1. However, cotreatment with SFP effectively reversed this action of Dex. Furthermore, silencing of Nrf2 by

  7. The RB/E2F pathway and regulation of RNA processing

    Energy Technology Data Exchange (ETDEWEB)

    Ahlander, Joseph [Department of Molecular and Cellular Biology, 1007 East Lowell Street, University of Arizona, Tucson, AZ 85721 (United States); Bosco, Giovanni, E-mail: gbosco@email.arizona.edu [Department of Molecular and Cellular Biology, 1007 East Lowell Street, University of Arizona, Tucson, AZ 85721 (United States)

    2009-07-03

    The retinoblastoma tumor suppressor protein (RB) is inactivated in a majority of cancers. RB restricts cell proliferation by inhibiting the E2F family of transcription factors. The current model for RB/E2F function describes its role in regulating transcription at gene promoters. Whether the RB or E2F proteins might play a role in gene expression beyond transcription initiation is not well known. This review describes evidence that points to a novel role for the RB/E2F network in the regulation of RNA processing, and we propose a model as a framework for future research. The elucidation of a novel role of RB in RNA processing will have a profound impact on our understanding of the role of this tumor suppressor family in cell and developmental biology.

  8. A computer-based microarray experiment design-system for gene-regulation pathway discovery.

    Science.gov (United States)

    Yoo, Changwon; Cooper, Gregory F

    2003-01-01

    This paper reports the methods and evaluation of a computer-based system that recommends microarray experimental design for biologists - causal discovery in Gene Expression data using Expected Value of Experimentation (GEEVE). The GEEVE system uses causal Bayesian networks and generates a decision tree for recommendations. To evaluate the GEEVE system, we first built an expression simulation model based on a gene regulation model assessed by an expert biologist. Using the simulation model, we conducted a controlled study that involved 10 biologists, some of whom used GEEVE and some of whom did not. The results show that biologists who used GEEVE reached correct causal assessments about gene regulation more often than did those biologists who did not use GEEVE.

  9. Leptin stimulates pituitary prolactin release through an extracellular signal-regulated kinase-dependent pathway

    DEFF Research Database (Denmark)

    Tipsmark, Christian K; Strom, Christina N; Bailey, Sean T

    2008-01-01

    Leptin was initially identified as a regulator of appetite and weight control centers in the hypothalamus, but appears to be involved in a number of physiological processes. This study was carried out to examine the possible role of leptin in regulating prolactin (PRL) release using the teleost...... pituitary model system. This advantageous system allows isolation of a nearly pure population of lactotropes in their natural, in situ aggregated state. The rostral pars distalis were dissected from tilapia pituitaries and exposed to varying concentrations of leptin (0, 1, 10, 100 nM) for 1 h. Release...... of PRL was stimulated by leptin in a potent and concentration-dependent manner. A time-course experiment showed that the strongest response in PRL release with leptin occurs within the first hour (approximately sixfold), and stimulation was sustained after 16 h (approximately twofold). Many...

  10. DMPD: PI3K and negative regulation of TLR signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available (.svg) HTML File (.html) CSML File (.csml) Open .csml file with CIOPlayer Open .csml file with CIOPlayer - ※...mmunol. 2003 Jul;24(7):358-63. (.png) (.svg) (.html) (.csml) Show PI3K and negative regulation of TLR signal...CIO Playerのご利用上の注意 Open .csml file with CIO Open .csml file with CIO - ※CIOのご利用上の注意 ...

  11. Arabidopsis TCP20 links regulation of growth and cell division control pathways

    OpenAIRE

    2005-01-01

    During postembryonic plant development, cell division is coupled to cell growth. There is a stringent requirement to couple these processes in shoot and root meristems. As cells pass through meristems, they transit through zones with high rates of cell growth and proliferation during organogenesis. This transition implies a need for coordinate regulation of genes underpinning these two fundamental cell functions. Here, we report a mechanism for coregulation of cell division control genes and ...

  12. Discrete redox signaling pathways regulate photosynthetic light-harvesting and chloroplast gene transcription.

    Directory of Open Access Journals (Sweden)

    John F Allen

    Full Text Available In photosynthesis in chloroplasts, two related regulatory processes balance the actions of photosystems I and II. These processes are short-term, post-translational redistribution of light-harvesting capacity, and long-term adjustment of photosystem stoichiometry initiated by control of chloroplast DNA transcription. Both responses are initiated by changes in the redox state of the electron carrier, plastoquinone, which connects the two photosystems. Chloroplast Sensor Kinase (CSK is a regulator of transcription of chloroplast genes for reaction centres of the two photosystems, and a sensor of plastoquinone redox state. We asked whether CSK is also involved in regulation of absorbed light energy distribution by phosphorylation of light-harvesting complex II (LHC II. Chloroplast thylakoid membranes isolated from a CSK T-DNA insertion mutant and from wild-type Arabidopsis thaliana exhibit similar light- and redox-induced (32P-labelling of LHC II and changes in 77 K chlorophyll fluorescence emission spectra, while room-temperature chlorophyll fluorescence emission transients from Arabidopsis leaves are perturbed by inactivation of CSK. The results indicate indirect, pleiotropic effects of reaction centre gene transcription on regulation of photosynthetic light-harvesting in vivo. A single, direct redox signal is transmitted separately to discrete transcriptional and post-translational branches of an integrated cytoplasmic regulatory system.

  13. Baicalein, a Bioflavonoid, Prevents Cisplatin-Induced Acute Kidney Injury by Up-Regulating Antioxidant Defenses and Down-Regulating the MAPKs and NF-κB Pathways.

    Directory of Open Access Journals (Sweden)

    Bidya Dhar Sahu

    Full Text Available Acute renal failure is a serious complication of the anticancer drug cisplatin. The potential role of baicalein, a naturally occurring bioflavonoid on cisplatin-induced renal injury is unknown. Here, we assessed the effect of baicalein against a murine model of cisplatin-induced acute renal failure and investigated the underlying possible mechanisms. Renal function, kidney histology, inflammation, oxidative stress, renal mitochondrial function, proteins involved in apoptosis, nuclear translocation of Nrf2 and effects on intracellular signaling pathways such as MAPKs, and NF-κB were assessed. Pretreatment with baicalein ameliorated the cisplatin-induced renal oxidative stress, apoptosis and inflammation and improved kidney injury and function. Baicalein inhibited the cisplatin-induced expression of iNOS, TNF-α, IL-6 and mononuclear cell infiltration and concealed redox-sensitive transcription factor NF-κB activation via reduced DNA-binding activity, IκBα phosphorylation and p65 nuclear translocation in kidneys. Further studies demonstrated baicalein markedly attenuated cisplatin-induced p38 MAPK, ERK1/2 and JNK phosphorylation in kidneys. Baicalein also restored the renal antioxidants and increased the amount of total and nuclear accumulation of Nrf2 and downstream target protein, HO-1 in kidneys. Moreover, baicalein preserved mitochondrial respiratory enzyme activities and inhibited cisplatin-induced apoptosis by suppressing p53 expression, Bax/Bcl-2 imbalance, cytochrome c release and activation of caspase-9, caspase-3 and PARP. Our findings suggest that baicalein ameliorates cisplatin-induced renal damage through up-regulation of antioxidant defense mechanisms and down regulation of the MAPKs and NF-κB signaling pathways.

  14. Baicalein, a Bioflavonoid, Prevents Cisplatin-Induced Acute Kidney Injury by Up-Regulating Antioxidant Defenses and Down-Regulating the MAPKs and NF-κB Pathways.

    Science.gov (United States)

    Sahu, Bidya Dhar; Mahesh Kumar, Jerald; Sistla, Ramakrishna

    2015-01-01

    Acute renal failure is a serious complication of the anticancer drug cisplatin. The potential role of baicalein, a naturally occurring bioflavonoid on cisplatin-induced renal injury is unknown. Here, we assessed the effect of baicalein against a murine model of cisplatin-induced acute renal failure and investigated the underlying possible mechanisms. Renal function, kidney histology, inflammation, oxidative stress, renal mitochondrial function, proteins involved in apoptosis, nuclear translocation of Nrf2 and effects on intracellular signaling pathways such as MAPKs, and NF-κB were assessed. Pretreatment with baicalein ameliorated the cisplatin-induced renal oxidative stress, apoptosis and inflammation and improved kidney injury and function. Baicalein inhibited the cisplatin-induced expression of iNOS, TNF-α, IL-6 and mononuclear cell infiltration and concealed redox-sensitive transcription factor NF-κB activation via reduced DNA-binding activity, IκBα phosphorylation and p65 nuclear translocation in kidneys. Further studies demonstrated baicalein markedly attenuated cisplatin-induced p38 MAPK, ERK1/2 and JNK phosphorylation in kidneys. Baicalein also restored the renal antioxidants and increased the amount of total and nuclear accumulation of Nrf2 and downstream target protein, HO-1 in kidneys. Moreover, baicalein preserved mitochondrial respiratory enzyme activities and inhibited cisplatin-induced apoptosis by suppressing p53 expression, Bax/Bcl-2 imbalance, cytochrome c release and activation of caspase-9, caspase-3 and PARP. Our findings suggest that baicalein ameliorates cisplatin-induced renal damage through up-regulation of antioxidant defense mechanisms and down regulation of the MAPKs and NF-κB signaling pathways.

  15. Active β-catenin is regulated by the PTEN/PI3 kinase pathway: a role for protein phosphatase PP2A

    Science.gov (United States)

    Persad, Amit; Venkateswaran, Geetha; Hao, Li; Garcia, Maria E.; Yoon, Jenny; Sidhu, Jaskiran; Persad, Sujata

    2016-01-01

    Dysregulation of Wnt/β-catenin signaling has been associated with the development and progression of many cancers. The stability and subcellular localization of β-catenin, a dual functional protein that plays a role in intracellular adhesion and in regulating gene expression, is tightly regulated. However, little is known about the transcriptionally active form of β-catenin, Active Beta Catenin (ABC), that is unphosphorylated at serine 37 (Ser37) and threonine 41 (Thr41). Elucidating the mechanism by which β-catenin is activated to generate ABC is vital to the development of therapeutic strategies to block β-catenin signaling for cancer treatment. Using melanoma, breast and prostate cancer cell lines, we show that while cellular β-catenin levels are regulated by the Wnt pathway, cellular ABC levels are mainly regulated by the PI3K pathway and are dependent on the phosphatase activity of the protein phosphatase PP2A. Furthermore, we demonstrate that although the PI3K/PTEN pathway does not regulate total β-catenin protein levels within the cell, it plays a role in regulating the subcellular localization of β-catenin. Our results support a novel functional interaction/cross-talk between the PTEN/PI3K and Wnt pathways in the regulation of the subcellular/nuclear levels of ABC, which is crucially important for the protein's activity as a transcription factor and its biological effects in health and disease.

  16. The DET1-COP1-HY5 Pathway Constitutes a Multipurpose Signaling Module Regulating Plant Photomorphogenesis and Thermomorphogenesis

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    Carolin Delker

    2014-12-01

    Full Text Available Developmental plasticity enables plants to respond to elevated ambient temperatures by adapting their shoot architecture. On the cellular level, the basic-helix-loop-helix (bHLH transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4 coordinates this response by activating hormonal modules that in turn regulate growth. In addition to an unknown temperature-sensing mechanism, it is currently not understood how temperature regulates PIF4 activity. Using a forward genetic approach in Arabidopsis thaliana, we present extensive genetic evidence demonstrating that the DE-ETIOLATED 1 (DET1-CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1-ELONGATED HYPOCOTYL 5 (HY5-dependent photomorphogenesis pathway transcriptionally regulates PIF4 to coordinate seedling growth in response to elevated temperature. Our findings demonstrate that two of the most prevalent environmental cues, light and temperature, share a much larger set of signaling components than previously assumed. Similar to the toolbox concept in animal embryonic patterning, multipurpose signaling modules might have evolved in plants to translate various environmental stimuli into adaptational growth processes.

  17. A Novel Role for Matrix Metalloproteinases In Regulating Mammary Stem Cell Function via the Wnt Signaling Pathway

    Science.gov (United States)

    Kessenbrock, Kai; Dijkgraaf, Gerrit J. P.; Lawson, Devon A.; Littlepage, Laurie E.; Shahi, Payam; Pieper, Ursula; Werb, Zena

    2013-01-01

    SUMMARY The microenvironment provides cues that control the behavior of epithelial stem and progenitor cells. Here, we identify matrix metalloproteinase-3 (MMP3) as a novel regulator of Wnt signaling and mammary stem cell (MaSC) activity. We show that MMP3 overexpression promotes hyperplastic epithelial growth, surprisingly, in a non-proteolytic manner via its hemopexin (HPX) domain. We demonstrate that MMP3-HPX specifically binds and inactivates Wnt5b, a non-canonical Wnt ligand that inhibits canonical Wnt signaling and mammary epithelial outgrowth in vivo. Indeed, transplants overexpressing MMP3 display increased canonical Wnt signaling, demonstrating that MMP3 is an extracellular regulator of the Wnt signaling pathway. MMP3-deficient mice exhibit decreased MaSC populations and diminished mammary reconstituting activity, while MMP3 overexpression elevates MaSC function indicating that MMP3 is necessary for the maintenance of MaSCs. Our study reveals a novel mechanism by a microenvironmental protease that regulates Wnt signaling and impacts adult epithelial stem cell function. PMID:23871604

  18. Childhood Maltreatment Exposure and Disruptions in Emotion Regulation: A Transdiagnostic Pathway to Adolescent Internalizing and Externalizing Psychopathology.

    Science.gov (United States)

    Heleniak, Charlotte; Jenness, Jessica L; Stoep, Ann Vander; McCauley, Elizabeth; McLaughlin, Katie A

    2016-06-01

    Child maltreatment is a robust risk factor for internalizing and externalizing psychopathology in children and adolescents. We examined the role of disruptions in emotion regulation processes as a developmental mechanism linking child maltreatment to the onset of multiple forms of psychopathology in adolescents. Specifically, we examined whether child maltreatment was associated with emotional reactivity and maladaptive cognitive and behavioral responses to distress, including rumination and impulsive behaviors, in two separate samples. We additionally investigated whether each of these components of emotion regulation were associated with internalizing and externalizing psychopathology and mediated the association between child maltreatment and psychopathology. Study 1 included a sample of 167 adolescents recruited based on exposure to physical, sexual, or emotional abuse. Study 2 included a sample of 439 adolescents in a community-based cohort study followed prospectively for 5 years. In both samples, child maltreatment was associated with higher levels of internalizing psychopathology, elevated emotional reactivity, and greater habitual engagement in rumination and impulsive responses to distress. In Study 2, emotional reactivity and maladaptive responses to distress mediated the association between child maltreatment and both internalizing and externalizing psychopathology. These findings provide converging evidence for the role of emotion regulation deficits as a transdiagnostic developmental pathway linking child maltreatment with multiple forms of psychopathology.

  19. Ndrg3 gene regulates DSB repair during meiosis through modulation the ERK signal pathway in the male germ cells.

    Science.gov (United States)

    Pan, Hongjie; Zhang, Xuan; Jiang, Hanwei; Jiang, Xiaohua; Wang, Liu; Qi, Qi; Bi, Yuan; Wang, Jian; Shi, Qinghua; Li, Runsheng

    2017-03-14

    The N-myc downstream regulated gene (NDRG) family consists of 4 members, NDRG-1, -2, -3, -4. Physiologically, we found Ndrg3, a critical gene which led to homologous lethality in the early embryo development, regulated the male meiosis in mouse. The expression of Ndrg3 was enhanced specifically in germ cells, and reached its peak level in the pachytene stage spermatocyte. Haplo-insufficiency of Ndrg3 gene led to sub-infertility during the male early maturation. In the Ndrg3(+/-) germ cells, some meiosis events such as DSB repair and synaptonemal complex formation were impaired. Disturbances on meiotic prophase progression and spermatogenesis were observed. In mechanism, the attenuation of pERK1/2 signaling was detected in the heterozygous testis. With our primary spermatocyte culture system, we found that lactate promoted DSB repair via ERK1/2 signaling in the male mouse germ cells in vitro. Deficiency of Ndrg3 gene attenuated the activation of ERK which further led to the aberrancy of DSB repair in the male germ cells in mouse. Taken together, we reported that Ndrg3 gene modulated the lactate induced ERK pathway to facilitate DSB repair in male germ cells, which further regulated meiosis and subsequently fertility in male mouse.

  20. Pleiotrophin promotes microglia proliferation and secretion of neurotrophic factors by activating extracellular signal-regulated kinase 1/2 pathway.

    Science.gov (United States)

    Miao, Jiayin; Ding, Minghui; Zhang, Aiwu; Xiao, Zijian; Qi, Weiwei; Luo, Ning; Di, Wei; Tao, Yuqian; Fang, Yannan

    2012-12-01

    Pleiotrophin (PTN) is an effective neuroprotective factor and its expression is strikingly increased in microglia after ischemia/reperfusion injury. However, whether PTN could provide neurotrophic support to neurons by regulating microglia function is not clear. In this study, we demonstrated that the expression of PTN was induced in microglia after oxygen-glucose deprivation/reperfusion. PTN promoted the proliferation of microglia by enhancing the G1 to S phase transition. PTN also stimulated the secretion of brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF) and nerve growth factor (NGF) in microglia, but did not upregulate the expression of proinflammatory factors such as TNF-α, IL-1β and iNOS. Mechanistically, we found that PTN increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 in microglia in both concentration-dependent and time-dependent manners. In addition, ERK1/2 inhibitor U0126 abolished the proliferation and G1 to S phase transition of microglia stimulated by PTN, and inhibited the production of BDNF, CNTF and NGF induced by PTN. In conclusion, our results demonstrated that PTN-ERK1/2 pathway plays important role in regulating microglia growth and secretion of neurotrophic factors. These findings provide new insight into the neuroprotective role of PTN and suggest that PTN is a new target for therapeutic intervention of stroke.

  1. Ndrg3 gene regulates DSB repair during meiosis through modulation the ERK signal pathway in the male germ cells

    Science.gov (United States)

    Pan, Hongjie; Zhang, Xuan; Jiang, Hanwei; Jiang, Xiaohua; Wang, Liu; Qi, Qi; Bi, Yuan; Wang, Jian; Shi, Qinghua; Li, Runsheng

    2017-01-01

    The N-myc downstream regulated gene (NDRG) family consists of 4 members, NDRG-1, -2, -3, -4. Physiologically, we found Ndrg3, a critical gene which led to homologous lethality in the early embryo development, regulated the male meiosis in mouse. The expression of Ndrg3 was enhanced specifically in germ cells, and reached its peak level in the pachytene stage spermatocyte. Haplo-insufficiency of Ndrg3 gene led to sub-infertility during the male early maturation. In the Ndrg3+/− germ cells, some meiosis events such as DSB repair and synaptonemal complex formation were impaired. Disturbances on meiotic prophase progression and spermatogenesis were observed. In mechanism, the attenuation of pERK1/2 signaling was detected in the heterozygous testis. With our primary spermatocyte culture system, we found that lactate promoted DSB repair via ERK1/2 signaling in the male mouse germ cells in vitro. Deficiency of Ndrg3 gene attenuated the activation of ERK which further led to the aberrancy of DSB repair in the male germ cells in mouse. Taken together, we reported that Ndrg3 gene modulated the lactate induced ERK pathway to facilitate DSB repair in male germ cells, which further regulated meiosis and subsequently fertility in male mouse. PMID:28290521

  2. Beta-adrenergic signals regulate cardiac differentiation of mouse embryonic stem cells via mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Yan, Lihui; Jia, Zhuqing; Cui, Jingjing; Yang, Hongtao; Yang, Huangtian; Zhang, Yongzhen; Zhou, Chunyan

    2011-08-01

    As embryonic stem cell-derived cardiomyocytes (ESC-CMs) have the potential to be used in cell replacement therapy, an understanding of the signaling mechanisms that regulate their terminal differentiation is imperative. In previous studies, we discovered the presence of adrenergic and muscarinic receptors in mouse embryonic stem cells (ESCs). However, little is known about the role of these receptors in cardiac differentiation and development, which is critically important in cardiac physiology and pharmacology. Here, we demonstrated that a β-adrenergic receptor (β-AR) agonist significantly enhanced cardiac differentiation as indicated by a higher percentage of beating embryoid bodies and a higher expression level of cardiac markers. Application of β1-AR and β2-AR antagonists partly abolished the effect of the β-AR agonist. In addition, by administering selective inhibitors we found that the effect of β-AR was driven via p38 mitogen-activated protein kinase and extracellular-signal regulated kinase pathway. These findings suggest that ESCs are also a target for β-adrenergic regulation and β-adrenergic signaling plays a role in ESC cardiac differentiation.

  3. Alternative oxidase pathway optimizes photosynthesis during osmotic and temperature stress by regulating cellular ROS, malate valve and antioxidative systems

    Directory of Open Access Journals (Sweden)

    DINAKAR eCHALLABATHULA

    2016-02-01

    results indicated the importance of AOX pathway in optimizing photosynthesis under both hyper-osmotic stress and sub-optimal temperatures. Regulation of ROS through redox couples related to malate valve and antioxidant system by AOX pathway to optimize photosynthesis under these stresses are discussed.

  4. Quantitative trait loci mapping reveals candidate pathways regulating cell cycle duration in Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Siwo Geoffrey

    2010-10-01

    Full Text Available Abstract Background Elevated parasite biomass in the human red blood cells can lead to increased malaria morbidity. The genes and mechanisms regulating growth and development of Plasmodium falciparum through its erythrocytic cycle are not well understood. We previously showed that strains HB3 and Dd2 diverge in their proliferation rates, and here use quantitative trait loci mapping in 34 progeny from a cross between these parent clones along with integrative bioinformatics to identify genetic loci and candidate genes that control divergences in cell cycle duration. Results Genetic mapping of cell cycle duration revealed a four-locus genetic model, including a major genetic effect on chromosome 12, which accounts for 75% of the inherited phenotype variation. These QTL span 165 genes, the majority of which have no predicted function based on homology. We present a method to systematically prioritize candidate genes using the extensive sequence and transcriptional information available for the parent lines. Putative functions were assigned to the prioritized genes based on protein interaction networks and expression eQTL from our earlier study. DNA metabolism or antigenic variation functional categories were enriched among our prioritized candidate genes. Genes were then analyzed to determine if they interact with cyclins or other proteins known to be involved in the regulation of cell cycle. Conclusions We show that the divergent proliferation rate between a drug resistant and drug sensitive parent clone is under genetic regulation and is segregating as a complex trait in 34 progeny. We map a major locus along with additional secondary effects, and use the wealth of genome data to identify key candidate genes. Of particular interest are a nucleosome assembly protein (PFL0185c, a Zinc finger transcription factor (PFL0465c both on chromosome 12 and a ribosomal protein L7Ae-related on chromosome 4 (PFD0960c.

  5. Sirtuin 3 regulates Foxo3a-mediated antioxidant pathway in microglia.

    Science.gov (United States)

    Rangarajan, P; Karthikeyan, A; Lu, J; Ling, E-A; Dheen, S T

    2015-12-17

    Microglia are the prime cellular sources of reactive oxygen species (ROS) in the central nervous system (CNS). Chronic activation of microglia has been linked to aging-associated neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD) since they produce excessive amounts of ROS for a prolonged duration leading to oxidative stress. The present study was aimed at investigating the expression and role of Sirtuin 3 (Sirt3), a protein deacetylase which is implicated in regulating cellular ROS levels. It has been shown that Sirt3 reduces cellular ROS levels by deacetylating forkhead box O 3a (Foxo3a), a transcription factor which transactivates antioxidant genes, catalase (Cat) and manganese superoxide dismutase (mnSod). In the present study, Sirt3 immunoreactivity was localized in the ameboid microglial cells distributed in the corpus callosum (CC) of the early postnatal rat brain and diminished in the ramified microglial cells in the CC of the adult rat brain. A marked induction of Sirt3 expression was seen in lipopolysaccharide (LPS)-activated microglia in vivo and in vitro as well as in adult rat brains subjected to traumatic brain injury (TBI). Knockdown of Sirt3 in microglia led to an increase in the cellular and mitochondrial ROS and decrease in the expression of antioxidant, mnSod which is indicative of the function of Sirt3 in ROS regulation in microglia. Conversely, Sirt3 overexpression led to increase in the expression of antioxidants Cat and mnSod. Further, increase in the expression and nuclear translocation of Foxo3a was observed following Sirt3 overexpression, suggesting that Sirt3 regulates ROS by inducing the expression of antioxidants via activation of Foxo3a. The above results point to an antioxidant defense mechanism presented by Sirt3 through the activation of Foxo3a, in microglia.

  6. Environmental control of the Pom1-dependent cell-size regulation pathway in fission yeast

    OpenAIRE

    Kelkar, M.

    2015-01-01

    Cells couple their growth and division rate in response to nutrient availability to maintain a constant size. This co-ordination happens either at the G1-S or the G2-M transition of the cell cycle. In the rod-shaped fission yeast, size regulation happens at the G2-M transition prior to mitotic commitment. Recent studies have focused on the role of the DYRK-family protein kinase Pom1, which forms gradients emanating from cell poles and inhibits the mitotic activator kinase Cdr2, present at the...

  7. GABA metabolism pathway genes, UGA1 and GAD1, regulate replicative lifespan in Saccharomycescerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, Yuka; Tamura, Takayuki [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan); Yoshida, Ryo [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Ohta, Shinji [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan); Fukusaki, Eiichiro [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mukai, Yukio, E-mail: y_mukai@nagahama-i-bio.ac.jp [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan)

    2011-04-01

    Highlights: {yields}We demonstrate that two genes in the yeast GABA metabolism pathway affect aging. {yields} Deletion of the UGA1 or GAD1 genes extends replicative lifespan. {yields} Addition of GABA to wild-type cultures has no effect on lifespan. {yields} Intracellular GABA levels do not differ in longevity mutants and wild-type cells. {yields} Levels of tricarboxylic acid cycle intermediates positively correlate with lifespan. -- Abstract: Many of the genes involved in aging have been identified in organisms ranging from yeast to human. Our previous study showed that deletion of the UGA3 gene-which encodes a zinc-finger transcription factor necessary for {gamma}-aminobutyric acid (GABA)-dependent induction of the UGA1 (GABA aminotransferase), UGA2 (succinate semialdehyde dehydrogenase), and UGA4 (GABA permease) genes-extends replicative lifespan in the budding yeast Saccharomycescerevisiae. Here, we found that deletion of UGA1 lengthened the lifespan, as did deletion of UGA3; in contrast, strains with UGA2 or UGA4 deletions exhibited no lifespan extension. The {Delta}uga1 strain cannot deaminate GABA to succinate semialdehyde. Deletion of GAD1, which encodes the glutamate decarboxylase that converts glutamate into GABA, also increased lifespan. Therefore, two genes in the GABA metabolism pathway, UGA1 and GAD1, were identified as aging genes. Unexpectedly, intracellular GABA levels in mutant cells (except for {Delta}uga2 cells) did not differ from those in wild-type cells. Addition of GABA to culture media, which induces transcription of the UGA structural genes, had no effect on replicative lifespan of wild-type cells. Multivariate analysis of {sup 1}H nuclear magnetic resonance spectra for the whole-cell metabolite levels demonstrated a separation between long-lived and normal-lived strains. Gas chromatography-mass spectrometry analysis of identified metabolites showed that levels of tricarboxylic acid cycle intermediates positively correlated with lifespan

  8. Regulation of enhanced cerebrovascular expression of proinflammatory mediators in experimental subarachnoid hemorrhage via the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase pathway

    Directory of Open Access Journals (Sweden)

    Maddahi Aida

    2012-12-01

    Full Text Available Abstract Background Subarachnoid hemorrhage (SAH is associated with high morbidity and mortality. It is suggested that the associated inflammation is mediated through activation of the mitogen-activated protein kinase (MAPK pathway which plays a crucial role in the pathogenesis of delayed cerebral ischemia after SAH. The aim of this study was first to investigate the timecourse of altered expression of proinflammatory cytokines and matrix metalloproteinase in the cerebral arteries walls following SAH. Secondly, we investigated whether administration of a specific mitogen-activated protein kinase kinase (MEK1/2 inhibitor, U0126, given at 6 h after SAH prevents activation of the MEK/extracellular signal-regulated kinase 1/2 pathway and the upregulation of cerebrovascular inflammatory mediators and improves neurological function. Methods SAH was induced in rats by injection of 250 μl of autologous blood into basal cisterns. U0126 was given intracisternally using two treatment regimens: (A treatments at 6, 12, 24 and 36 h after SAH and experiments terminated at 48 h after SAH, or (B treatments at 6, 12, and 24 h after SAH and terminated at 72 h after SAH. Cerebral arteries were harvested and interleukin (IL-6, IL-1β, tumor necrosis factor α (TNFα, matrix metalloproteinase (MMP-9 and phosphorylated ERK1/2 (pERK1/2 levels investigated by immunohistochemistry. Early activation of pERK1/2 was measured by western blot. Functional neurological outcome after SAH was also analyzed. Results Expression levels of IL-1β, IL-6, MMP-9 and pERK1/2 proteins were elevated over time with an early increase at around 6 h and a late peak at 48 to 72 h post-SAH in cerebral arteries. Enhanced expression of TNFα in cerebral arteries started at 24 h and increased until 96 h. In addition, SAH induced sensorimotor and spontaneous behavior deficits in the animals. Treatment with U0126 starting at 6 h after SAH prevented activation of MEK-ERK1/2 signaling. Further, U0126

  9. NF-κB signaling pathways regulated by CARMA family of scaffold proteins

    Institute of Scientific and Technical Information of China (English)

    Marzenna Blonska; Xin Lin

    2011-01-01

    The NF-κB family of transcription factors plays a crucial role in cell activation,survival and proliferation.Its aberrant activity results in cancer,immunodeficiency or autoimmune disorders.Over the past two decades,tremendous progress has been made in our understanding of the signals that regulate NF-κB activation,especially how scaffold proteins link different receptors to the NF-κB-activating complex,the IκB kinase complex.The growing number of these scaffolds underscores the complexity of the signaling networks in different cell types.In this review,we discuss the role of scaffold molecules in signaling cascades induced by stimulation of antigen receptors,G-protein-coupled receptors and C-type Lectin receptors,resulting in NF-κB activation.Especially,we focus on the family of Caspase recruitment domain(CARD)-con