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Sample records for replication stress signal

  1. Replication stress and oxidative damage contribute to aberrant constitutive activation of DNA damage signalling in human gliomas

    DEFF Research Database (Denmark)

    Bartkova, J; Hamerlik, P; Stockhausen, Marie

    2010-01-01

    brain and grade II astrocytomas, despite the degree of DDR activation was higher in grade II tumors. Markers indicative of ongoing DNA replication stress (Chk1 activation, Rad17 phosphorylation, replication protein A foci and single-stranded DNA) were present in GBM cells under high- or low...... and indicate that replication stress, rather than oxidative stress, fuels the DNA damage signalling in early stages of astrocytoma development.......Malignant gliomas, the deadliest of brain neoplasms, show rampant genetic instability and resistance to genotoxic therapies, implicating potentially aberrant DNA damage response (DDR) in glioma pathogenesis and treatment failure. Here, we report on gross, aberrant constitutive activation of DNA...

  2. The leukemia-associated Rho guanine nucleotide exchange factor LARG is required for efficient replication stress signaling.

    Science.gov (United States)

    Beveridge, Ryan D; Staples, Christopher J; Patil, Abhijit A; Myers, Katie N; Maslen, Sarah; Skehel, J Mark; Boulton, Simon J; Collis, Spencer J

    2014-01-01

    We previously identified and characterized TELO2 as a human protein that facilitates efficient DNA damage response (DDR) signaling. A subsequent yeast 2-hybrid screen identified LARG; Leukemia-Associated Rho Guanine Nucleotide Exchange Factor (also known as Arhgef12), as a potential novel TELO2 interactor. LARG was previously shown to interact with Pericentrin (PCNT), which, like TELO2, is required for efficient replication stress signaling. Here we confirm interactions between LARG, TELO2 and PCNT and show that a sub-set of LARG co-localizes with PCNT at the centrosome. LARG-deficient cells exhibit replication stress signaling defects as evidenced by; supernumerary centrosomes, reduced replication stress-induced γH2AX and RPA nuclear foci formation, and reduced activation of the replication stress signaling effector kinase Chk1 in response to hydroxyurea. As such, LARG-deficient cells are sensitive to replication stress-inducing agents such as hydroxyurea and mitomycin C. Conversely we also show that depletion of TELO2 and the replication stress signaling kinase ATR leads to RhoA signaling defects. These data therefore reveal a level of crosstalk between the RhoA and DDR signaling pathways. Given that mutations in both ATR and PCNT can give rise to the related primordial dwarfism disorders of Seckel Syndrome and Microcephalic osteodysplastic primordial dwarfism type II (MOPDII) respectively, which both exhibit defects in ATR-dependent checkpoint signaling, these data also raise the possibility that mutations in LARG or disruption to RhoA signaling may be contributory factors to the etiology of a sub-set of primordial dwarfism disorders.

  3. p38 (MAPK) stress signalling in replicative senescence in fibroblasts from progeroid and genomic instability syndromes.

    Science.gov (United States)

    Tivey, Hannah S E; Brook, Amy J C; Rokicki, Michal J; Kipling, David; Davis, Terence

    2013-02-01

    Werner Syndrome (WS) is a human segmental progeria resulting from mutations in a DNA helicase. WS fibroblasts have a shortened replicative capacity, an aged appearance, and activated p38 MAPK, features that can be modulated by inhibition of the p38 pathway. Loss of the WRNp RecQ helicase has been shown to result in replicative stress, suggesting that a link between faulty DNA repair and stress-induced premature cellular senescence may lead to premature ageing in WS. Other progeroid syndromes that share overlapping pathophysiological features with WS also show defects in DNA processing, raising the possibility that faulty DNA repair, leading to replicative stress and premature cellular senescence, might be a more widespread feature of premature ageing syndromes. We therefore analysed replicative capacity, cellular morphology and p38 activation, and the effects of p38 inhibition, in fibroblasts from a range of progeroid syndromes. In general, populations of young fibroblasts from non-WS progeroid syndromes do not have a high level of cells with an enlarged morphology and F-actin stress fibres, unlike young WS cells, although this varies between strains. p38 activation and phosphorylated HSP27 levels generally correlate well with cellular morphology, and treatment with the p38 inhibitor SB203580 effects cellular morphology only in strains with enlarged cells and phosphorylated HSP27. For some syndromes fibroblast replicative capacity was within the normal range, whereas for others it was significantly shorter (e.g. HGPS and DKC). However, although in most cases SB203580 extended replicative capacity, with the exception of WS and DKC the magnitude of the effect was not significantly different from normal dermal fibroblasts. This suggests that stress-induced premature cellular senescence via p38 activation is restricted to a small subset of progeroid syndromes.

  4. Replication stress and oxidative damage contribute to aberrant constitutive activation of DNA damage signalling in human gliomas

    DEFF Research Database (Denmark)

    Bartkova, J; Hamerlik, P; Stockhausen, Marie;

    2010-01-01

    damage signalling in low- and high-grade human gliomas, and analyze the sources of such endogenous genotoxic stress. Based on analyses of human glioblastoma multiforme (GBM) cell lines, normal astrocytes and clinical specimens from grade II astrocytomas (n=41) and grade IV GBM (n=60), we conclude......, initially limiting cell proliferation (low Ki-67 index) and selecting for mutations of p53 and likely other genes that allow escape (higher Ki-67 index) from the checkpoint and facilitate tumor progression. Overall, these results support the potential role of the DDR machinery as a barrier to gliomagenesis...... and indicate that replication stress, rather than oxidative stress, fuels the DNA damage signalling in early stages of astrocytoma development....

  5. Exploiting replicative stress to treat cancer

    DEFF Research Database (Denmark)

    Dobbelstein, Matthias; Sørensen, Claus Storgaard

    2015-01-01

    DNA replication in cancer cells is accompanied by stalling and collapse of the replication fork and signalling in response to DNA damage and/or premature mitosis; these processes are collectively known as 'replicative stress'. Progress is being made to increase our understanding of the mechanisms...

  6. DNA replication stress: causes, resolution and disease.

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    Mazouzi, Abdelghani; Velimezi, Georgia; Loizou, Joanna I

    2014-11-15

    DNA replication is a fundamental process of the cell that ensures accurate duplication of the genetic information and subsequent transfer to daughter cells. Various pertubations, originating from endogenous or exogenous sources, can interfere with proper progression and completion of the replication process, thus threatening genome integrity. Coordinated regulation of replication and the DNA damage response is therefore fundamental to counteract these challenges and ensure accurate synthesis of the genetic material under conditions of replication stress. In this review, we summarize the main sources of replication stress and the DNA damage signaling pathways that are activated in order to preserve genome integrity during DNA replication. We also discuss the association of replication stress and DNA damage in human disease and future perspectives in the field. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  7. A whole genome RNAi screen identifies replication stress response genes.

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    Kavanaugh, Gina; Ye, Fei; Mohni, Kareem N; Luzwick, Jessica W; Glick, Gloria; Cortez, David

    2015-11-01

    Proper DNA replication is critical to maintain genome stability. When the DNA replication machinery encounters obstacles to replication, replication forks stall and the replication stress response is activated. This response includes activation of cell cycle checkpoints, stabilization of the replication fork, and DNA damage repair and tolerance mechanisms. Defects in the replication stress response can result in alterations to the DNA sequence causing changes in protein function and expression, ultimately leading to disease states such as cancer. To identify additional genes that control the replication stress response, we performed a three-parameter, high content, whole genome siRNA screen measuring DNA replication before and after a challenge with replication stress as well as a marker of checkpoint kinase signalling. We identified over 200 replication stress response genes and subsequently analyzed how they influence cellular viability in response to replication stress. These data will serve as a useful resource for understanding the replication stress response.

  8. Assembly of Slx4 signaling complexes behind DNA replication forks.

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    Balint, Attila; Kim, TaeHyung; Gallo, David; Cussiol, Jose Renato; Bastos de Oliveira, Francisco M; Yimit, Askar; Ou, Jiongwen; Nakato, Ryuichiro; Gurevich, Alexey; Shirahige, Katsuhiko; Smolka, Marcus B; Zhang, Zhaolei; Brown, Grant W

    2015-08-13

    Obstructions to replication fork progression, referred to collectively as DNA replication stress, challenge genome stability. In Saccharomyces cerevisiae, cells lacking RTT107 or SLX4 show genome instability and sensitivity to DNA replication stress and are defective in the completion of DNA replication during recovery from replication stress. We demonstrate that Slx4 is recruited to chromatin behind stressed replication forks, in a region that is spatially distinct from that occupied by the replication machinery. Slx4 complex formation is nucleated by Mec1 phosphorylation of histone H2A, which is recognized by the constitutive Slx4 binding partner Rtt107. Slx4 is essential for recruiting the Mec1 activator Dpb11 behind stressed replication forks, and Slx4 complexes are important for full activity of Mec1. We propose that Slx4 complexes promote robust checkpoint signaling by Mec1 by stably recruiting Dpb11 within a discrete domain behind the replication fork, during DNA replication stress.

  9. Targeting DNA Replication Stress for Cancer Therapy

    Science.gov (United States)

    Zhang, Jun; Dai, Qun; Park, Dongkyoo; Deng, Xingming

    2016-01-01

    The human cellular genome is under constant stress from extrinsic and intrinsic factors, which can lead to DNA damage and defective replication. In normal cells, DNA damage response (DDR) mediated by various checkpoints will either activate the DNA repair system or induce cellular apoptosis/senescence, therefore maintaining overall genomic integrity. Cancer cells, however, due to constitutive growth signaling and defective DDR, may exhibit “replication stress” —a phenomenon unique to cancer cells that is described as the perturbation of error-free DNA replication and slow-down of DNA synthesis. Although replication stress has been proven to induce genomic instability and tumorigenesis, recent studies have counterintuitively shown that enhancing replicative stress through further loosening of the remaining checkpoints in cancer cells to induce their catastrophic failure of proliferation may provide an alternative therapeutic approach. In this review, we discuss the rationale to enhance replicative stress in cancer cells, past approaches using traditional radiation and chemotherapy, and emerging approaches targeting the signaling cascades induced by DNA damage. We also summarize current clinical trials exploring these strategies and propose future research directions including the use of combination therapies, and the identification of potential new targets and biomarkers to track and predict treatment responses to targeting DNA replication stress. PMID:27548226

  10. Targeting DNA Replication Stress for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2016-08-01

    Full Text Available The human cellular genome is under constant stress from extrinsic and intrinsic factors, which can lead to DNA damage and defective replication. In normal cells, DNA damage response (DDR mediated by various checkpoints will either activate the DNA repair system or induce cellular apoptosis/senescence, therefore maintaining overall genomic integrity. Cancer cells, however, due to constitutive growth signaling and defective DDR, may exhibit “replication stress” —a phenomenon unique to cancer cells that is described as the perturbation of error-free DNA replication and slow-down of DNA synthesis. Although replication stress has been proven to induce genomic instability and tumorigenesis, recent studies have counterintuitively shown that enhancing replicative stress through further loosening of the remaining checkpoints in cancer cells to induce their catastrophic failure of proliferation may provide an alternative therapeutic approach. In this review, we discuss the rationale to enhance replicative stress in cancer cells, past approaches using traditional radiation and chemotherapy, and emerging approaches targeting the signaling cascades induced by DNA damage. We also summarize current clinical trials exploring these strategies and propose future research directions including the use of combination therapies, and the identification of potential new targets and biomarkers to track and predict treatment responses to targeting DNA replication stress.

  11. RPA mediates recombination repair during replication stress and is displaced from DNA by checkpoint signalling in human cells

    DEFF Research Database (Denmark)

    Sleeth, Kate M; Sørensen, Claus Storgaard; Issaeva, Natalia

    2007-01-01

    The replication protein A (RPA) is involved in most, if not all, nuclear metabolism involving single-stranded DNA. Here, we show that RPA is involved in genome maintenance at stalled replication forks by the homologous recombination repair system in humans. Depletion of the RPA protein inhibited...... the formation of RAD51 nuclear foci after hydroxyurea-induced replication stalling leading to persistent unrepaired DNA double-strand breaks (DSBs). We demonstrate a direct role of RPA in homology directed recombination repair. We find that RPA is dispensable for checkpoint kinase 1 (Chk1) activation...... and that RPA directly binds RAD52 upon replication stress, suggesting a direct role in recombination repair. In addition we show that inhibition of Chk1 with UCN-01 decreases dissociation of RPA from the chromatin and inhibits association of RAD51 and RAD52 with DNA. Altogether, our data suggest a direct role...

  12. Replication Stress: A Lifetime of Epigenetic Change

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    Simran Khurana

    2015-09-01

    Full Text Available DNA replication is essential for cell division. Challenges to the progression of DNA polymerase can result in replication stress, promoting the stalling and ultimately collapse of replication forks. The latter involves the formation of DNA double-strand breaks (DSBs and has been linked to both genome instability and irreversible cell cycle arrest (senescence. Recent technological advances have elucidated many of the factors that contribute to the sensing and repair of stalled or broken replication forks. In addition to bona fide repair factors, these efforts highlight a range of chromatin-associated changes at and near sites of replication stress, suggesting defects in epigenome maintenance as a potential outcome of aberrant DNA replication. Here, we will summarize recent insight into replication stress-induced chromatin-reorganization and will speculate on possible adverse effects for gene expression, nuclear integrity and, ultimately, cell function.

  13. Rescue from replication stress during mitosis.

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    Fragkos, Michalis; Naim, Valeria

    2017-04-03

    Genomic instability is a hallmark of cancer and a common feature of human disorders, characterized by growth defects, neurodegeneration, cancer predisposition, and aging. Recent evidence has shown that DNA replication stress is a major driver of genomic instability and tumorigenesis. Cells can undergo mitosis with under-replicated DNA or unresolved DNA structures, and specific pathways are dedicated to resolving these structures during mitosis, suggesting that mitotic rescue from replication stress (MRRS) is a key process influencing genome stability and cellular homeostasis. Deregulation of MRRS following oncogene activation or loss-of-function of caretaker genes may be the cause of chromosomal aberrations that promote cancer initiation and progression. In this review, we discuss the causes and consequences of replication stress, focusing on its persistence in mitosis as well as the mechanisms and factors involved in its resolution, and the potential impact of incomplete replication or aberrant MRRS on tumorigenesis, aging and disease.

  14. More forks on the road to replication stress recovery

    Institute of Scientific and Technical Information of China (English)

    Chris Allen; Amanda K. Ashley; Robert Hromas; Jac A. Nickoloff

    2011-01-01

    High-fidelity replication of DNA, and its accurate segregation to daughter cells, is critical for maintaining genome stability and suppressing cancer. DNA replication forks are stalled by many DNA lesions, activating checkpoint proteins that stabilize stalled forks.Stalled forks may eventually collapse, producing a broken DNA end. Fork restart is typically mediated by proteins initially identified by their rotes in homologous recombination repair of DNA double-strand breaks (DSBs). In recent years, several proteins involved in DSB repair by non-homologous end joining (NHEJ) have been implicated in the replication stress response, including DNA-PKcs, Ku,DNA Ligase IV-XRCC4, Artemis, XLF and Metnase. It is currently unclear whether NHEJ proteins are involved in the replication stress response through indirect (signaling) roles, and/or direct roles involving DNA end joining. Additional complexity in the replication stress response centers around RPA, which undergoes significant post-translational modification after stress, and RAD52, a conserved HR protein whose role in DSB repair may have shifted to another protein in higher eukaryotes, such as BRCA2, but retained its rote in fork restart. Most cancer therapeutic strategies create DNA reputation stress. Thus, it is imperative to gain a better understanding of replication stress response proteins and pathways to improve cancer therapy.

  15. Are renal ciliopathies (replication) stressed out?

    NARCIS (Netherlands)

    Slaats, Gisela G; Giles, R

    2015-01-01

    Juvenile renal failure is commonly caused by the ciliopathy nephronophthisis (NPHP). Since all NPHP genes regulate cilia function, it has been assumed that NPHP onset is due to cilia loss. However, recent data suggest that DNA damage caused by replication stress, possibly concomitant with or upstrea

  16. The DNA damage checkpoint response to replication stress: A Game of Forks.

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    Rachel eJossen

    2013-03-01

    Full Text Available Conditions challenging replication fork progression, collectively referred to as replication stress, represent a major source of genomic instability and are associated to cancer onset. The replication checkpoint, a specialized branch of the DNA damage checkpoint, monitors fork problems and triggers a cellular response aimed at preserving genome integrity. Here, we review the mechanisms by which the replication checkpoint monitors and responds to replication stress, focusing on the checkpoint-mediated pathways contributing to protect replication fork integrity. We discuss how cells achieve checkpoint signaling inactivation once replication stress is overcome and how a failure to timely revert checkpoint-mediated changes in cellular physiology might impact on replication dynamics and genome integrity. We also highlight the checkpoint function as an anti-cancer barrier preventing cells malignant transformation following oncogene-induced replication stress.

  17. The Role of the Transcriptional Response to DNA Replication Stress.

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    Herlihy, Anna E; de Bruin, Robertus A M

    2017-03-02

    During DNA replication many factors can result in DNA replication stress. The DNA replication stress checkpoint prevents the accumulation of replication stress-induced DNA damage and the potential ensuing genome instability. A critical role for post-translational modifications, such as phosphorylation, in the replication stress checkpoint response has been well established. However, recent work has revealed an important role for transcription in the cellular response to DNA replication stress. In this review, we will provide an overview of current knowledge of the cellular response to DNA replication stress with a specific focus on the DNA replication stress checkpoint transcriptional response and its role in the prevention of replication stress-induced DNA damage.

  18. TRAIP is a PCNA-binding ubiquitin ligase that protects genome stability after replication stress

    DEFF Research Database (Denmark)

    Hoffmann, Saskia; Smedegaard, Stine; Nakamura, Kyosuke;

    2016-01-01

    , allowing cells to mitigate the threats to genome stability posed by replication stress. We identify the E3 ubiquitin ligase TRAIP as a new factor at active and stressed replication forks that directly interacts with PCNA via a conserved PCNA-interacting peptide (PIP) box motif. We show that TRAIP promotes......Cellular genomes are highly vulnerable to perturbations to chromosomal DNA replication. Proliferating cell nuclear antigen (PCNA), the processivity factor for DNA replication, plays a central role as a platform for recruitment of genome surveillance and DNA repair factors to replication forks...... ATR-dependent checkpoint signaling in human cells by facilitating the generation of RPA-bound single-stranded DNA regions upon replication stress in a manner that critically requires its E3 ligase activity and is potentiated by the PIP box. Consequently, loss of TRAIP function leads to enhanced...

  19. A Comprehensive Analysis of the Dynamic Response to Aphidicolin-Mediated Replication Stress Uncovers Targets for ATM and ATMIN.

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    Mazouzi, Abdelghani; Stukalov, Alexey; Müller, André C; Chen, Doris; Wiedner, Marc; Prochazkova, Jana; Chiang, Shih-Chieh; Schuster, Michael; Breitwieser, Florian P; Pichlmair, Andreas; El-Khamisy, Sherif F; Bock, Christoph; Kralovics, Robert; Colinge, Jacques; Bennett, Keiryn L; Loizou, Joanna I

    2016-04-14

    The cellular response to replication stress requires the DNA-damage-responsive kinase ATM and its cofactor ATMIN; however, the roles of this signaling pathway following replication stress are unclear. To identify the functions of ATM and ATMIN in response to replication stress, we utilized both transcriptomics and quantitative mass-spectrometry-based phosphoproteomics. We found that replication stress induced by aphidicolin triggered widespread changes in both gene expression and protein phosphorylation patterns. These changes gave rise to distinct early and late replication stress responses. Furthermore, our analysis revealed previously unknown targets of ATM and ATMIN downstream of replication stress. We demonstrate ATMIN-dependent phosphorylation of H2AX and of CRMP2, a protein previously implicated in Alzheimer's disease but not in the DNA damage response. Overall, our dataset provides a comprehensive resource for discovering the cellular responses to replication stress and, potentially, associated pathologies. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  20. A Comprehensive Analysis of the Dynamic Response to Aphidicolin-Mediated Replication Stress Uncovers Targets for ATM and ATMIN

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    Abdelghani Mazouzi

    2016-04-01

    Full Text Available The cellular response to replication stress requires the DNA-damage-responsive kinase ATM and its cofactor ATMIN; however, the roles of this signaling pathway following replication stress are unclear. To identify the functions of ATM and ATMIN in response to replication stress, we utilized both transcriptomics and quantitative mass-spectrometry-based phosphoproteomics. We found that replication stress induced by aphidicolin triggered widespread changes in both gene expression and protein phosphorylation patterns. These changes gave rise to distinct early and late replication stress responses. Furthermore, our analysis revealed previously unknown targets of ATM and ATMIN downstream of replication stress. We demonstrate ATMIN-dependent phosphorylation of H2AX and of CRMP2, a protein previously implicated in Alzheimer’s disease but not in the DNA damage response. Overall, our dataset provides a comprehensive resource for discovering the cellular responses to replication stress and, potentially, associated pathologies.

  1. TRAIP is a PCNA-binding ubiquitin ligase that protects genome stability after replication stress

    DEFF Research Database (Denmark)

    Hoffmann, Saskia; Smedegaard, Stine; Nakamura, Kyosuke

    2016-01-01

    , allowing cells to mitigate the threats to genome stability posed by replication stress. We identify the E3 ubiquitin ligase TRAIP as a new factor at active and stressed replication forks that directly interacts with PCNA via a conserved PCNA-interacting peptide (PIP) box motif. We show that TRAIP promotes...... ATR-dependent checkpoint signaling in human cells by facilitating the generation of RPA-bound single-stranded DNA regions upon replication stress in a manner that critically requires its E3 ligase activity and is potentiated by the PIP box. Consequently, loss of TRAIP function leads to enhanced...... chromosomal instability and decreased cell survival after replication stress. These findings establish TRAIP as a PCNA-binding ubiquitin ligase with an important role in protecting genome integrity after obstacles to DNA replication....

  2. RAD52 Facilitates Mitotic DNA Synthesis Following Replication Stress

    DEFF Research Database (Denmark)

    Bhowmick, Rahul; Minocherhomji, Sheroy; Hickson, Ian D

    2016-01-01

    Homologous recombination (HR) is necessary to counteract DNA replication stress. Common fragile site (CFS) loci are particularly sensitive to replication stress and undergo pathological rearrangements in tumors. At these loci, replication stress frequently activates DNA repair synthesis in mitosis....... This mitotic DNA synthesis, termed MiDAS, requires the MUS81-EME1 endonuclease and a non-catalytic subunit of the Pol-delta complex, POLD3. Here, we examine the contribution of HR factors in promoting MiDAS in human cells. We report that RAD51 and BRCA2 are dispensable for MiDAS but are required to counteract...

  3. Replication forks reverse at high frequency upon replication stress in Physarum polycephalum.

    Science.gov (United States)

    Maric, Chrystelle; Bénard, Marianne

    2014-12-01

    The addition of hydroxyurea after the onset of S phase allows replication to start and permits the successive detecting of replication-dependent joint DNA molecules and chicken foot structures in the synchronous nuclei of Physarum polycephalum. We find evidence for a very high frequency of reversed replication forks upon replication stress. The formation of these reversed forks is dependent on the presence of joint DNA molecules, the impediment of the replication fork progression by hydroxyurea, and likely on the propensity of some replication origins to reinitiate replication to counteract the action of this compound. As hydroxyurea treatment enables us to successively detect the appearance of joint DNA molecules and then of reversed replication forks, we propose that chicken foot structures are formed both from the regression of hydroxyurea-frozen joint DNA molecules and from hydroxyurea-stalled replication forks. These experiments underscore the transient nature of replication fork regression, which becomes detectable due to the hydroxyurea-induced slowing down of replication fork progression.

  4. Replication stress activates DNA repair synthesis in mitosis

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    Minocherhomji, Sheroy; Ying, Songmin; Bjerregaard, Victoria A

    2015-01-01

    mitosis serves as the trigger for completion of DNA replication at CFS loci in human cells. Given that this POLD3-dependent mitotic DNA synthesis is enhanced in aneuploid cancer cells that exhibit intrinsically high levels of chromosomal instability (CIN(+)) and replicative stress, we suggest...

  5. ATM Couples Replication Stress and Metabolic Reprogramming during Cellular Senescence

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    Katherine M. Aird

    2015-05-01

    Full Text Available Replication stress induced by nucleotide deficiency plays an important role in cancer initiation. Replication stress in primary cells typically activates the cellular senescence tumor-suppression mechanism. Senescence bypass correlates with development of cancer, a disease characterized by metabolic reprogramming. However, the role of metabolic reprogramming in the cellular response to replication stress has been little explored. Here, we report that ataxia telangiectasia mutated (ATM plays a central role in regulating the cellular response to replication stress by shifting cellular metabolism. ATM inactivation bypasses senescence induced by replication stress triggered by nucleotide deficiency. This was due to restoration of deoxyribonucleotide triphosphate (dNTP levels through both upregulation of the pentose phosphate pathway via increased glucose-6-phosphate dehydrogenase (G6PD activity and enhanced glucose and glutamine consumption. These phenotypes were mediated by a coordinated suppression of p53 and upregulation of c-MYC downstream of ATM inactivation. Our data indicate that ATM status couples replication stress and metabolic reprogramming during senescence.

  6. DNA replication stress restricts ribosomal DNA copy number.

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    Salim, Devika; Bradford, William D; Freeland, Amy; Cady, Gillian; Wang, Jianmin; Pruitt, Steven C; Gerton, Jennifer L

    2017-09-15

    Ribosomal RNAs (rRNAs) in budding yeast are encoded by ~100-200 repeats of a 9.1kb sequence arranged in tandem on chromosome XII, the ribosomal DNA (rDNA) locus. Copy number of rDNA repeat units in eukaryotic cells is maintained far in excess of the requirement for ribosome biogenesis. Despite the importance of the repeats for both ribosomal and non-ribosomal functions, it is currently not known how "normal" copy number is determined or maintained. To identify essential genes involved in the maintenance of rDNA copy number, we developed a droplet digital PCR based assay to measure rDNA copy number in yeast and used it to screen the yeast conditional temperature-sensitive mutant collection of essential genes. Our screen revealed that low rDNA copy number is associated with compromised DNA replication. Further, subculturing yeast under two separate conditions of DNA replication stress selected for a contraction of the rDNA array independent of the replication fork blocking protein, Fob1. Interestingly, cells with a contracted array grew better than their counterparts with normal copy number under conditions of DNA replication stress. Our data indicate that DNA replication stresses select for a smaller rDNA array. We speculate that this liberates scarce replication factors for use by the rest of the genome, which in turn helps cells complete DNA replication and continue to propagate. Interestingly, tumors from mini chromosome maintenance 2 (MCM2)-deficient mice also show a loss of rDNA repeats. Our data suggest that a reduction in rDNA copy number may indicate a history of DNA replication stress, and that rDNA array size could serve as a diagnostic marker for replication stress. Taken together, these data begin to suggest the selective pressures that combine to yield a "normal" rDNA copy number.

  7. Managing Single-Stranded DNA during Replication Stress in Fission Yeast

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    Sarah A. Sabatinos

    2015-09-01

    Full Text Available Replication fork stalling generates a variety of responses, most of which cause an increase in single-stranded DNA. ssDNA is a primary signal of replication distress that activates cellular checkpoints. It is also a potential source of genome instability and a substrate for mutation and recombination. Therefore, managing ssDNA levels is crucial to chromosome integrity. Limited ssDNA accumulation occurs in wild-type cells under stress. In contrast, cells lacking the replication checkpoint cannot arrest forks properly and accumulate large amounts of ssDNA. This likely occurs when the replication fork polymerase and helicase units are uncoupled. Some cells with mutations in the replication helicase (mcm-ts mimic checkpoint-deficient cells, and accumulate extensive areas of ssDNA to trigger the G2-checkpoint. Another category of helicase mutant (mcm4-degron causes fork stalling in early S-phase due to immediate loss of helicase function. Intriguingly, cells realize that ssDNA is present, but fail to detect that they accumulate ssDNA, and continue to divide. Thus, the cellular response to replication stalling depends on checkpoint activity and the time that replication stress occurs in S-phase. In this review we describe the signs, signals, and symptoms of replication arrest from an ssDNA perspective. We explore the possible mechanisms for these effects. We also advise the need for caution when detecting and interpreting data related to the accumulation of ssDNA.

  8. The DNA Replication Stress Hypothesis of Alzheimer’s Disease

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    Yuri B. Yurov

    2011-01-01

    Full Text Available A well-recognized theory of Alzheimer’s disease (AD pathogenesis suggests ectopic cell cycle events to mediate neurodegeneration. Vulnerable neurons of the AD brain exhibit biomarkers of cell cycle progression and DNA replication suggesting a reentry into the cell cycle. Chromosome reduplication without proper cell cycle completion and mitotic division probably causes neuronal cell dysfunction and death. However, this theory seems to require some inputs in accordance with the generally recognized amyloid cascade theory as well as to explain causes and consequences of genomic instability (aneuploidy in the AD brain. We propose that unscheduled and incomplete DNA replication (replication stress destabilizes (epigenomic landscape in the brain and leads to DNA replication “catastrophe” causing cell death during the S phase (replicative cell death. DNA replication stress can be a key element of the pathogenetic cascade explaining the interplay between ectopic cell cycle events and genetic instabilities in the AD brain. Abnormal cell cycle reentry and somatic genome variations can be used for updating the cell cycle theory introducing replication stress as a missing link between cell genetics and neurobiology of AD.

  9. Stress responses and replication of plasmids in bacterial cells

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    Wegrzyn Alicja

    2002-05-01

    Full Text Available Abstract Plasmids, DNA (or rarely RNA molecules which replicate in cells autonomously (independently of chromosomes as non-essential genetic elements, play important roles for microbes grown under specific environmental conditions as well as in scientific laboratories and in biotechnology. For example, bacterial plasmids are excellent models in studies on regulation of DNA replication, and their derivatives are the most commonly used vectors in genetic engineering. Detailed mechanisms of replication initiation, which is the crucial process for efficient maintenance of plasmids in cells, have been elucidated for several plasmids. However, to understand plasmid biology, it is necessary to understand regulation of plasmid DNA replication in response to different environmental conditions in which host cells exist. Knowledge of such regulatory processes is also very important for those who use plasmids as expression vectors to produce large amounts of recombinant proteins. Variable conditions in large-scale fermentations must influence replication of plasmid DNA in cells, thus affecting the efficiency of recombinant gene expression significantly. Contrary to extensively investigated biochemistry of plasmid replication, molecular mechanisms of regulation of plasmid DNA replication in response to various environmental stress conditions are relatively poorly understood. There are, however, recently published studies that add significant data to our knowledge on relations between cellular stress responses and control of plasmid DNA replication. In this review we focus on plasmids derived from bacteriophage λ that are among the best investigated replicons. Nevertheless, recent results of studies on other plasmids are also discussed shortly.

  10. The mammalian INO80 chromatin remodeling complex is required for replication stress recovery

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    Vassileva, Ivelina; Yanakieva, Iskra; Peycheva, Michaela; Gospodinov, Anastas; Anachkova, Boyka

    2014-01-01

    A number of studies have implicated the yeast INO80 chromatin remodeling complex in DNA replication, but the function of the human INO80 complex during S phase remains poorly understood. Here, we have systematically investigated the involvement of the catalytic subunit of the human INO80 complex during unchallenged replication and under replication stress by following the effects of its depletion on cell survival, S-phase checkpoint activation, the fate of individual replication forks, and the consequences of fork collapse. We report that INO80 was specifically needed for efficient replication elongation, while it was not required for initiation of replication. In the absence of the Ino80 protein, cells became hypersensitive to hydroxyurea and displayed hyperactive ATR-Chk1 signaling. Using bulk and fiber labeling of DNA, we found that cells deficient for Ino80 and Arp8 had impaired replication restart after treatment with replication inhibitors and accumulated double-strand breaks as evidenced by the formation of γ-H2AX and Rad51 foci. These data indicate that under conditions of replication stress mammalian INO80 protects stalled forks from collapsing and allows their subsequent restart. PMID:25016522

  11. Replication stress activates DNA repair synthesis in mitosis.

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    Minocherhomji, Sheroy; Ying, Songmin; Bjerregaard, Victoria A; Bursomanno, Sara; Aleliunaite, Aiste; Wu, Wei; Mankouri, Hocine W; Shen, Huahao; Liu, Ying; Hickson, Ian D

    2015-12-10

    Oncogene-induced DNA replication stress has been implicated as a driver of tumorigenesis. Many chromosomal rearrangements characteristic of human cancers originate from specific regions of the genome called common fragile sites (CFSs). CFSs are difficult-to-replicate loci that manifest as gaps or breaks on metaphase chromosomes (termed CFS 'expression'), particularly when cells have been exposed to replicative stress. The MUS81-EME1 structure-specific endonuclease promotes the appearance of chromosome gaps or breaks at CFSs following replicative stress. Here we show that entry of cells into mitotic prophase triggers the recruitment of MUS81 to CFSs. The nuclease activity of MUS81 then promotes POLD3-dependent DNA synthesis at CFSs, which serves to minimize chromosome mis-segregation and non-disjunction. We propose that the attempted condensation of incompletely duplicated loci in early mitosis serves as the trigger for completion of DNA replication at CFS loci in human cells. Given that this POLD3-dependent mitotic DNA synthesis is enhanced in aneuploid cancer cells that exhibit intrinsically high levels of chromosomal instability (CIN(+)) and replicative stress, we suggest that targeting this pathway could represent a new therapeutic approach.

  12. Replication stress, a source of epigenetic aberrations in cancer?

    DEFF Research Database (Denmark)

    Jasencakova, Zusana; Groth, Anja

    2010-01-01

    . Chromatin organization is transiently disrupted during DNA replication and maintenance of epigenetic information thus relies on faithful restoration of chromatin on the new daughter strands. Acute replication stress challenges proper chromatin restoration by deregulating histone H3 lysine 9 mono......-methylation on new histones and impairing parental histone recycling. This could facilitate stochastic epigenetic silencing by laying down repressive histone marks at sites of fork stalling. Deregulation of replication in response to oncogenes and other tumor-promoting insults is recognized as a significant source...... of genome instability in cancer. We propose that replication stress not only presents a threat to genome stability, but also jeopardizes chromatin integrity and increases epigenetic plasticity during tumorigenesis....

  13. A Blm-Recql5 partnership in replication stress response

    Institute of Scientific and Technical Information of China (English)

    Xincheng Lu; Hua Lou; Guangbin Luo

    2011-01-01

    Deficiencies in DNA damage response and repair not only can result in genome instability and cancer predisposition, but also can render the cancer cells intrinsically more vulnerable to certain types of DNA damage insults. Particularly, replication stress is both a hallmark of human cancers and a common instigator for genome instability and cell death. Here, we review our work based on the genetic knockout studies on Blm and Recql5, two members of the mammalian RecQ helicase family. These studies have uncovered a unique partnership between these two helicases in the implementation of proper mitigation strategies under different circumstances to promote DNA replication and cell survival and suppress genome instability and cancer. In particular, current studies have revealed the presence of a novel Recql5/RECQL5-dependent mechanism for suppressing replication fork collapse in response to global replication fork stalling following exposure to camptothecin (CPT), a topoisomerase I inhibitor, and a potent inhibitor of DNA replication. The unique partnership between Blm and Recql5 in coping with the challenge imposed by replication stress is discussed. In addition, given that irinotecan and topotecan, two CPT derivatives, are currently used in clinic for treating human cancer patients with very promising results, the potential implication of the new findings from these studies in anticancer treatments is also discussed.

  14. Potential biomarkers of DNA replication stress in cancer

    DEFF Research Database (Denmark)

    Ren, Liqun; Chen, Long; Wu, Wei

    2017-01-01

    Oncogene activation is an established driver of tumorigenesis. An apparently inevitable consequence of oncogene activation is the generation of DNA replication stress (RS), a feature common to most cancer cells. RS, in turn, is a causal factor in the development of chromosome instability (CIN), a...

  15. Phosphoproteomics Reveals Distinct Modes of Mec1/ATR Signaling During DNA Replication

    Science.gov (United States)

    de Oliveira, Francisco Meirelles Bastos; Kim, Dongsung; Cussiol, Jose Renato; Das, Jishnu; Jeong, Min Cheol; Doerfler, Lillian; Schmidt, Kristina Hildegard; Yu, Haiyuan; Smolka, Marcus Bustamante

    2015-01-01

    SUMMARY The Mec1/Tel1 kinases (human ATR/ATM) play numerous roles in the DNA replication stress response. Despite the multi-functionality of these kinases, studies of their in vivo action have mostly relied on a few well-established substrates. Here we employed a combined genetic-phosphoproteomic approach to monitor Mec1/Tel1 signaling in a systematic, unbiased and quantitative manner. Unexpectedly, we find that Mec1 is highly active during normal DNA replication, at levels comparable or higher than Mec1’s activation state induced by replication stress. This “replication-correlated” mode of Mec1 action requires the 9-1-1 clamp and the Dna2 lagging-strand factor, and is distinguishable from Mec1’s action in activating the downstream kinase Rad53. We propose that Mec1/ATR performs key functions during ongoing DNA synthesis that are distinct from their canonical checkpoint role during replication stress. PMID:25752575

  16. Mcm2 phosphorylation and the response to replicative stress

    Directory of Open Access Journals (Sweden)

    Stead Brent E

    2012-05-01

    Full Text Available Abstract Background The replicative helicase in eukaryotic cells is comprised of minichromosome maintenance (Mcm proteins 2 through 7 (Mcm2-7 and is a key target for regulation of cell proliferation. In addition, it is regulated in response to replicative stress. One of the protein kinases that targets Mcm2-7 is the Dbf4-dependent kinase Cdc7 (DDK. In a previous study, we showed that alanine mutations of the DDK phosphorylation sites at S164 and S170 in Saccharomyces cerevisiae Mcm2 result in sensitivity to caffeine and methyl methanesulfonate (MMS leading us to suggest that DDK phosphorylation of Mcm2 is required in response to replicative stress. Results We show here that a strain with the mcm2 allele lacking DDK phosphorylation sites (mcm2AA is also sensitive to the ribonucleotide reductase inhibitor, hydroxyurea (HU and to the base analogue 5-fluorouracil (5-FU but not the radiomimetic drug, phleomycin. We screened the budding yeast non-essential deletion collection for synthetic lethal interactions with mcm2AA and isolated deletions that include genes involved in the control of genome integrity and oxidative stress. In addition, the spontaneous mutation rate, as measured by mutations in CAN1, was increased in the mcm2AA strain compared to wild type, whereas with a phosphomimetic allele (mcm2EE the mutation rate was decreased. These results led to the idea that the mcm2AA strain is unable to respond properly to DNA damage. We examined this by screening the deletion collection for suppressors of the caffeine sensitivity of mcm2AA. Deletions that decrease spontaneous DNA damage, increase homologous recombination or slow replication forks were isolated. Many of the suppressors of caffeine sensitivity suppressed other phenotypes of mcm2AA including sensitivity to genotoxic drugs, the increased frequency of cells with RPA foci and the increased mutation rate. Conclusions Together these observations point to a role for DDK-mediated phosphorylation

  17. Enhancer of Rudimentary Homolog Affects the Replication Stress Response through Regulation of RNA Processing

    Science.gov (United States)

    Kavanaugh, Gina; Zhao, Runxiang; Guo, Yan; Mohni, Kareem N.; Glick, Gloria; Lacy, Monica E.; Hutson, M. Shane; Ascano, Manuel

    2015-01-01

    Accurate replication of DNA is imperative for the maintenance of genomic integrity. We identified Enhancer of Rudimentary Homolog (ERH) using a whole-genome RNA interference (RNAi) screen to discover novel proteins that function in the replication stress response. Here we report that ERH is important for DNA replication and recovery from replication stress. ATR pathway activity is diminished in ERH-deficient cells. The reduction in ATR signaling corresponds to a decrease in the expression of multiple ATR pathway genes, including ATR itself. ERH interacts with multiple RNA processing complexes, including splicing regulators. Furthermore, splicing of ATR transcripts is deficient in ERH-depleted cells. Transcriptome-wide analysis indicates that ERH depletion affects the levels of ∼1,500 transcripts, with DNA replication and repair genes being highly enriched among those with reduced expression. Splicing defects were evident in ∼750 protein-coding genes, which again were enriched for DNA metabolism genes. Thus, ERH regulation of RNA processing is needed to ensure faithful DNA replication and repair. PMID:26100022

  18. IL1- and TGFβ-Nox4 signaling, oxidative stress and DNA damage response are shared features of replicative, oncogene-induced, and drug-induced paracrine ‘Bystander senescence’

    Science.gov (United States)

    Hubackova, Sona; Krejcikova, Katerina; Bartek, Jiri; Hodny, Zdenek

    2012-01-01

    Many cancers arise at sites of infection and inflammation. Cellular senescence, a permanent state of cell cycle arrest that provides a barrier against tumorigenesis, is accompanied by elevated proinflammatory cytokines such as IL1, IL6, IL8 and TNFα. Here we demonstrate that media conditioned by cells undergoing any of the three main forms of senescence, i.e. replicative, oncogene- and drug-induced, contain high levels of IL1, IL6, and TGFb capable of inducing reactive oxygen species (ROS)-mediated DNA damage response (DDR). Persistent cytokine signaling and activated DDR evoke senescence in normal bystander cells, accompanied by activation of the JAK/STAT, TGFβ/SMAD and IL1/NFκB signaling pathways. Whereas inhibition of IL6/STAT signaling had no effect on DDR induction in bystander cells, inhibition of either TGFβ/SMAD or IL1/NFκB pathway resulted in decreased ROS production and reduced DDR in bystander cells. Simultaneous inhibition of both TGFβ/SMAD and IL1/NFκB pathways completely suppressed DDR indicating that IL1 and TGFβ cooperate to induce and/or maintain bystander senescence. Furthermore, the observed IL1- and TGFβ-induced expression of NAPDH oxidase Nox4 indicates a mechanistic link between the senescence-associated secretory phenotype (SASP) and DNA damage signaling as a feature shared by development of all major forms of paracrine bystander senescence. PMID:23385065

  19. Telomere Replication Stress Induced by POT1 Inactivation Accelerates Tumorigenesis.

    Science.gov (United States)

    Pinzaru, Alexandra M; Hom, Robert A; Beal, Angela; Phillips, Aaron F; Ni, Eric; Cardozo, Timothy; Nair, Nidhi; Choi, Jaehyuk; Wuttke, Deborah S; Sfeir, Agnel; Denchi, Eros Lazzerini

    2016-06-01

    Genome sequencing studies have revealed a number of cancer-associated mutations in the telomere-binding factor POT1. Here, we show that when combined with p53 deficiency, depletion of murine POT1a in common lymphoid progenitor cells fosters genetic instability, accelerates the onset, and increases the severity of T cell lymphomas. In parallel, we examined human and mouse cells carrying POT1 mutations found in cutaneous T cell lymphoma (CTCL) patients. Inhibition of POT1 activates ATR-dependent DNA damage signaling and induces telomere fragility, replication fork stalling, and telomere elongation. Our data suggest that these phenotypes are linked to impaired CST (CTC1-STN1-TEN1) function at telomeres. Lastly, we show that proliferation of cancer cells lacking POT1 is enabled by the attenuation of the ATR kinase pathway. These results uncover a role for defective telomere replication during tumorigenesis.

  20. Telomere Replication Stress Induced by POT1 Inactivation Accelerates Tumorigenesis

    Directory of Open Access Journals (Sweden)

    Alexandra M. Pinzaru

    2016-06-01

    Full Text Available Genome sequencing studies have revealed a number of cancer-associated mutations in the telomere-binding factor POT1. Here, we show that when combined with p53 deficiency, depletion of murine POT1a in common lymphoid progenitor cells fosters genetic instability, accelerates the onset, and increases the severity of T cell lymphomas. In parallel, we examined human and mouse cells carrying POT1 mutations found in cutaneous T cell lymphoma (CTCL patients. Inhibition of POT1 activates ATR-dependent DNA damage signaling and induces telomere fragility, replication fork stalling, and telomere elongation. Our data suggest that these phenotypes are linked to impaired CST (CTC1-STN1-TEN1 function at telomeres. Lastly, we show that proliferation of cancer cells lacking POT1 is enabled by the attenuation of the ATR kinase pathway. These results uncover a role for defective telomere replication during tumorigenesis.

  1. Receptor tyrosine kinase signaling regulates replication of the peste des petits ruminants virus.

    Science.gov (United States)

    Chaudhary, K; Chaubey, K K; Singh, S V; Kumar, N

    2015-03-01

    In this study, we found out that blocking the receptor tyrosine kinase (RTK) signaling in Vero cells by tryphostin AG879 impairs the in vitro replication of the peste des petits ruminants virus (PPRV). A reduced virus replication in Trk1-knockdown (siRNA) Vero cells confirmed the essential role of RTK in the virus replication, in particular a specific regulation of viral RNA synthesis. These data represent the first evidence that the RTK signaling regulates replication of a morbillivirus.

  2. Identification of 30 protein species involved in replicative senescence and stress-induced premature senescence

    DEFF Research Database (Denmark)

    Dierick, Jean François; Kalume, Dário E; Wenders, Frédéric

    2002-01-01

    Exposure of human proliferative cells to subcytotoxic stress triggers stress-induced premature senescence (SIPS) which is characterized by many biomarkers of replicative senescence. Proteomic comparison of replicative senescence and stress-induced premature senescence indicates that, at the level....... These changes affect different cell functions, including energy metabolism, defense systems, maintenance of the redox potential, cell morphology and transduction pathways.......Exposure of human proliferative cells to subcytotoxic stress triggers stress-induced premature senescence (SIPS) which is characterized by many biomarkers of replicative senescence. Proteomic comparison of replicative senescence and stress-induced premature senescence indicates that, at the level...... of protein expression, stress-induced premature senescence and replicative senescence are different phenotypes sharing however similarities. In this study, we identified 30 proteins showing changes of expression level specific or common to replicative senescence and/or stress-induced premature senescence...

  3. The stress-activated protein kinases p38α/β and JNK1/2 cooperate with Chk1 to inhibit mitotic entry upon DNA replication arrest.

    Science.gov (United States)

    Llopis, Alba; Salvador, Noelia; Ercilla, Amaia; Guaita-Esteruelas, Sandra; Barrantes, Ivan del Barco; Gupta, Jalaj; Gaestel, Matthias; Davis, Roger J; Nebreda, Angel R; Agell, Neus

    2012-10-01

    Accurate DNA replication is crucial for the maintenance of genome integrity. To this aim, cells have evolved complex surveillance mechanisms to prevent mitotic entry in the presence of partially replicated DNA. ATR and Chk1 are key elements in the signal transduction pathways of DNA replication checkpoint; however, other kinases also make significant contributions. We show here that the stress kinases p38 and JNK are activated when DNA replication is blocked, and that their activity allows S/M, but not G 2/M, checkpoint maintenance when Chk1 is inhibited. Activation of both kinases by DNA replication inhibition is not mediated by the caffeine-sensitive kinases ATR or ATM. Phosphorylation of MKK3/6 and MKK4, p38 and JNK upstream kinases was also observed upon DNA replication inhibition. Using a genetic approach, we dissected the p38 pathway and showed that both p38α and p38β isoforms collaborate to inhibit mitotic entry. We further defined MKK3/6 and MK2/3 as the key upstream and downstream elements in the p38 signaling cascade after replication arrest. Accordingly, we found that the stress signaling pathways collaborate with Chk1 to keep cyclin B1/Cdk1 complexes inactive when DNA replication is inhibited, thereby preventing cell cycle progression when DNA replication is stalled. Our results show a complex response to replication stress, where multiple pathways are activated and fulfill overlapping roles to prevent mitotic entry with unreplicated DNA.

  4. The transcription elongation factor Bur1-Bur2 interacts with replication protein A and maintains genome stability during replication stress

    DEFF Research Database (Denmark)

    Clausing, Emanuel; Mayer, Andreas; Chanarat, Sittinan

    2010-01-01

    foci. Interestingly, the DNA damage sensitivity of an rfa1 mutant was suppressed by bur1 mutation, further underscoring a functional link between these two protein complexes. The transcription elongation factor Bur1-Bur2 interacts with RPA and maintains genome integrity during DNA replication stress....

  5. Slow Replication Fork Velocity of Homologous Recombination-Defective Cells Results from Endogenous Oxidative Stress.

    Science.gov (United States)

    Wilhelm, Therese; Ragu, Sandrine; Magdalou, Indiana; Machon, Christelle; Dardillac, Elodie; Técher, Hervé; Guitton, Jérôme; Debatisse, Michelle; Lopez, Bernard S

    2016-05-01

    Replications forks are routinely hindered by different endogenous stresses. Because homologous recombination plays a pivotal role in the reactivation of arrested replication forks, defects in homologous recombination reveal the initial endogenous stress(es). Homologous recombination-defective cells consistently exhibit a spontaneously reduced replication speed, leading to mitotic extra centrosomes. Here, we identify oxidative stress as a major endogenous source of replication speed deceleration in homologous recombination-defective cells. The treatment of homologous recombination-defective cells with the antioxidant N-acetyl-cysteine or the maintenance of the cells at low O2 levels (3%) rescues both the replication fork speed, as monitored by single-molecule analysis (molecular combing), and the associated mitotic extra centrosome frequency. Reciprocally, the exposure of wild-type cells to H2O2 reduces the replication fork speed and generates mitotic extra centrosomes. Supplying deoxynucleotide precursors to H2O2-exposed cells rescued the replication speed. Remarkably, treatment with N-acetyl-cysteine strongly expanded the nucleotide pool, accounting for the replication speed rescue. Remarkably, homologous recombination-defective cells exhibit a high level of endogenous reactive oxygen species. Consistently, homologous recombination-defective cells accumulate spontaneous γH2AX or XRCC1 foci that are abolished by treatment with N-acetyl-cysteine or maintenance at 3% O2. Finally, oxidative stress stimulated homologous recombination, which is suppressed by supplying deoxynucleotide precursors. Therefore, the cellular redox status strongly impacts genome duplication and transmission. Oxidative stress should generate replication stress through different mechanisms, including DNA damage and nucleotide pool imbalance. These data highlight the intricacy of endogenous replication and oxidative stresses, which are both evoked during tumorigenesis and senescence initiation

  6. Targeting radioresistant breast cancer cells by single agent CHK1 inhibitor via enhancing replication stress

    Science.gov (United States)

    Du, Zhanwen; Gao, Jinnan; Yang, Shuming; Gorityala, Shashank; Xiong, Xiahui; Deng, Ou; Ma, Zhefu; Yan, Chunhong; Susana, Gonzalo; Xu, Yan; Zhang, Junran

    2016-01-01

    Radiotherapy (RT) remains a standard therapeutic modality for breast cancer patients. However, intrinsic or acquired resistance limits the efficacy of RT. Here, we demonstrate that CHK1 inhibitor AZD7762 alone significantly inhibited the growth of radioresistant breast cancer cells (RBCC). Given the critical role of ATR/CHK1 signaling in suppressing oncogene-induced replication stress (RS), we hypothesize that CHK1 inhibition leads to the specific killing for RBCC due to its abrogation in the suppression of RS induced by oncogenes. In agreement, the expression of oncogenes c-Myc/CDC25A/c-Src/H-ras/E2F1 and DNA damage response (DDR) proteins ATR/CHK1/BRCA1/CtIP were elevated in RBCC. AZD7762 exposure led to significantly higher levels of RS in RBCC, compared to the parental cells. The mechanisms by which CHK1 inhibition led to specific increase of RS in RBCC were related to the interruptions in the replication fork dynamics and the homologous recombination (HR). In summary, RBCC activate oncogenic pathways and thus depend upon mechanisms controlled by CHK1 signaling to maintain RS under control for survival. Our study provided the first example where upregulating RS by CHK1 inhibitor contributes to the specific killing of RBCC, and highlight the importance of the CHK1 as a potential target for treatment of radioresistant cancer cells. PMID:27167194

  7. IL1- and TGFβ-Nox4 signaling, oxidative stress and DNA damage response are shared features of replicative, oncogene-induced, and drug-induced paracrine 'bystander senescence'

    National Research Council Canada - National Science Library

    Hubackova, Sona; Krejcikova, Katerina; Bartek, Jiri; Hodny, Zdenek

    2012-01-01

    ...)-mediated DNA damage response (DDR). Persistent cytokine signaling and activated DDR evoke senescence in normal bystander cells, accompanied by activation of the JAK/STAT, TGFβ/SMAD and IL1/NFκ...

  8. Environmental stress speeds up DNA replication in Pseudomonas putida in chemostat cultivations.

    Science.gov (United States)

    Lieder, Sarah; Jahn, Michael; Koepff, Joachim; Müller, Susann; Takors, Ralf

    2016-01-01

    Cellular response to different types of stress is the hallmark of the cell's strategy for survival. How organisms adjust their cell cycle dynamics to compensate for changes in environmental conditions is an important unanswered question in bacterial physiology. A cell using binary fission for reproduction passes through three stages during its cell cycle: a stage from cell birth to initiation of replication, a DNA replication phase and a period of cell division. We present a detailed analysis of durations of cell cycle phases, investigating their dynamics under environmental stress conditions. Applying continuous steady state cultivations (chemostats), the DNA content of a Pseudomonas putida KT2440 population was quantified with flow cytometry at distinct growth rates. Data-driven modeling revealed that under stress conditions, such as oxygen deprivation, solvent exposure and decreased iron availability, DNA replication was accelerated correlated to the severity of the imposed stress (up to 1.9-fold). Cells maintained constant growth rates by balancing the shortened replication phase with extended cell cycle phases before and after replication. Transcriptome data underpin the transcriptional upregulation of crucial genes of the replication machinery. Hence adaption of DNA replication speed appears to be an important strategy to withstand environmental stress.

  9. Deubiquitinases as a Signaling Target of Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Xiomaris M. Cotto-Rios

    2012-12-01

    Full Text Available Deubiquitinating enzymes (DUBs constitute a large family of cysteine proteases that have a broad impact on numerous biological and pathological processes, including the regulation of genomic stability. DUBs are often assembled onto multiprotein complexes to assist in their localization and substrate selection, yet it remains unclear how the enzymatic activity of DUBs is modulated by intracellular signals. Herein, we show that bursts of reactive oxygen species (ROS reversibly inactivate DUBs through the oxidation of the catalytic cysteine residue. Importantly, USP1, a key regulator of genomic stability, is reversibly inactivated upon oxidative stress. This, in part, explains the rapid nature of PCNA monoubiquitination-dependent DNA damage tolerance in response to oxidative DNA damage in replicating cells. We propose that DUBs of the cysteine protease family act as ROS sensors in human cells and that ROS-mediated DUB inactivation is a critical mechanism for fine-tuning stress-activated signaling pathways.

  10. Dengue-induced autophagy, virus replication and protection from cell death require ER stress (PERK) pathway activation.

    Science.gov (United States)

    Datan, E; Roy, S G; Germain, G; Zali, N; McLean, J E; Golshan, G; Harbajan, S; Lockshin, R A; Zakeri, Z

    2016-03-03

    A virus that reproduces in a host without killing cells can easily establish a successful infection. Previously, we showed that dengue-2, a virus that threatens 40% of the world, induces autophagy, enabling dengue to reproduce in cells without triggering cell death. Autophagy further protects the virus-laden cells from further insults. In this study, we evaluate how it does so; we show that dengue upregulates host pathways that increase autophagy, namely endoplasmic reticulum (ER) stress and ataxia telangiectasia mutated (ATM) signaling followed by production of reactive oxygen species (ROS). Inhibition of ER stress or ATM signaling abrogates the dengue-conferred protection against other cell stressors. Direct inhibition of ER stress response in infected cells decreases autophagosome turnover, reduces ROS production and limits reproduction of dengue virus. Blocking ATM activation, which is an early response to infection, decreases transcription of ER stress response proteins, but ATM has limited impact on production of ROS and virus titers. Production of ROS determines only late-onset autophagy in infected cells and is not necessary for dengue-induced protection from stressors. Collectively, these results demonstrate that among the multiple autophagy-inducing pathways during infection, ER stress signaling is more important to viral replication and protection of cells than either ATM or ROS-mediated signaling. To limit virus production and survival of dengue-infected cells, one must address the earliest phase of autophagy, induced by ER stress.

  11. Myc and Ras oncogenes engage different energy metabolism programs and evoke distinct patterns of oxidative and DNA replication stress.

    Science.gov (United States)

    Maya-Mendoza, Apolinar; Ostrakova, Jitka; Kosar, Martin; Hall, Arnaldur; Duskova, Pavlina; Mistrik, Martin; Merchut-Maya, Joanna Maria; Hodny, Zdenek; Bartkova, Jirina; Christensen, Claus; Bartek, Jiri

    2015-03-01

    Both Myc and Ras oncogenes impact cellular metabolism, deregulate redox homeostasis and trigger DNA replication stress (RS) that compromises genomic integrity. However, how are such oncogene-induced effects evoked and temporally related, to what extent are these kinetic parameters shared by Myc and Ras, and how are these cellular changes linked with oncogene-induced cellular senescence in different cell context(s) remain poorly understood. Here, we addressed the above-mentioned open questions by multifaceted comparative analyses of human cellular models with inducible expression of c-Myc and H-RasV12 (Ras), two commonly deregulated oncoproteins operating in a functionally connected signaling network. Our study of DNA replication parameters using the DNA fiber approach and time-course assessment of perturbations in glycolytic flux, oxygen consumption and production of reactive oxygen species (ROS) revealed the following results. First, overabundance of nuclear Myc triggered RS promptly, already after one day of Myc induction, causing slow replication fork progression and fork asymmetry, even before any metabolic changes occurred. In contrast, Ras overexpression initially induced a burst of cell proliferation and increased the speed of replication fork progression. However, after several days of induction Ras caused bioenergetic metabolic changes that correlated with slower DNA replication fork progression and the ensuing cell cycle arrest, gradually leading to senescence. Second, the observed oncogene-induced RS and metabolic alterations were cell-type/context dependent, as shown by comparative analyses of normal human BJ fibroblasts versus U2-OS sarcoma cells. Third, the energy metabolic reprogramming triggered by Ras was more robust compared to impact of Myc. Fourth, the detected oncogene-induced oxidative stress was due to ROS (superoxide) of non-mitochondrial origin and mitochondrial OXPHOS was reduced (Crabtree effect). Overall, our study provides novel

  12. Analysis of replication profiles reveals key role of RFC-Ctf18 in yeast replication stress response.

    Science.gov (United States)

    Crabbé, Laure; Thomas, Aubin; Pantesco, Véronique; De Vos, John; Pasero, Philippe; Lengronne, Armelle

    2010-11-01

    Maintenance of genome integrity relies on surveillance mechanisms that detect and signal arrested replication forks. Although evidence from budding yeast indicates that the DNA replication checkpoint (DRC) is primarily activated by single-stranded DNA (ssDNA), studies in higher eukaryotes have implicated primer ends in this process. To identify factors that signal primed ssDNA in Saccharomyces cerevisiae, we have screened a collection of checkpoint mutants for their ability to activate the DRC, using the repression of late origins as readout for checkpoint activity. This quantitative analysis reveals that neither RFC(Rad24) and the 9-1-1 clamp nor the alternative clamp loader RFC(Elg1) is required to signal paused forks. In contrast, we found that RFC(Ctf18) is essential for the Mrc1-dependent activation of Rad53 and for the maintenance of paused forks. These data identify RFC(Ctf18) as a key DRC mediator, potentially bridging Mrc1 and primed ssDNA to signal paused forks.

  13. Stress Sensors and Signal Transducers in Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Sergey Kryazhov

    2010-03-01

    Full Text Available In living cells, the perception of environmental stress and the subsequent transduction of stress signals are primary events in the acclimation to changes in the environment. Some molecular sensors and transducers of environmental stress cannot be identified by traditional and conventional methods. Based on genomic information, a systematic approach has been applied to the solution of this problem in cyanobacteria, involving mutagenesis of potential sensors and signal transducers in combination with DNA microarray analyses for the genome-wide expression of genes. Forty-five genes for the histidine kinases (Hiks, 12 genes for serine-threonine protein kinases (Spks, 42 genes for response regulators (Rres, seven genes for RNA polymerase sigma factors, and nearly 70 genes for transcription factors have been successfully inactivated by targeted mutagenesis in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Screening of mutant libraries by genome-wide DNA microarray analysis under various stress and non-stress conditions has allowed identification of proteins that perceive and transduce signals of environmental stress. Here we summarize recent progress in the identification of sensory and regulatory systems, including Hiks, Rres, Spks, sigma factors, transcription factors, and the role of genomic DNA supercoiling in the regulation of the responses of cyanobacterial cells to various types of stress.

  14. Replication stress interferes with histone recycling and predeposition marking of new histones.

    Science.gov (United States)

    Jasencakova, Zuzana; Scharf, Annette N D; Ask, Katrine; Corpet, Armelle; Imhof, Axel; Almouzni, Geneviève; Groth, Anja

    2010-03-12

    To restore chromatin on new DNA during replication, recycling of histones evicted ahead of the fork is combined with new histone deposition. The Asf1 histone chaperone, which buffers excess histones under stress, is a key player in this process. Yet how histones handled by human Asf1 are modified remains unclear. Here we identify marks on histones H3-H4 bound to Asf1 and changes induced upon replication stress. In S phase, distinct cytosolic and nuclear Asf1b complexes show ubiquitous H4K5K12diAc and heterogeneous H3 marks, including K9me1, K14ac, K18ac, and K56ac. Upon acute replication arrest, the predeposition mark H3K9me1 and modifications typical of chromatin accumulate in Asf1 complexes. In parallel, ssDNA is generated at replication sites, consistent with evicted histones being trapped with Asf1. During recovery, histones stored with Asf1 are rapidly used as replication resumes. This shows that replication stress interferes with predeposition marking and histone recycling with potential impact on epigenetic stability.

  15. Control of hepatitis B virus replication by interferons and Toll-like receptor signaling pathways.

    Science.gov (United States)

    Pei, Rong-Juan; Chen, Xin-Wen; Lu, Meng-Ji

    2014-09-07

    Hepatitis B virus (HBV) infection is one of the major causes of liver diseases, affecting more than 350 million people worldwide. The interferon (IFN)-mediated innate immune responses could restrict HBV replication at the different steps of viral life cycle. Indeed, IFN-α has been successfully used for treatment of patients with chronic hepatitis B. However, the role of the innate immune response in HBV replication and the mechanism of the anti-HBV effect of IFN-α are not completely explored. In this review, we summarized the currently available knowledge about the IFN-mediated anti-HBV effect in the HBV life cycle and the possible effectors downstream the IFN signaling pathway. The antiviral effect of Toll-like receptors (TLRs) in HBV replication is briefly discussed. The strategies exploited by HBV to evade the IFN- and TLR-mediated antiviral actions are summarized.

  16. BRCA1-regulated RRM2 expression protects glioblastoma cells from endogenous replication stress and promotes tumorigenicity

    DEFF Research Database (Denmark)

    Rasmussen, Rikke D.; Gajjar, Madhavsai K.; Tuckova, Lucie;

    2016-01-01

    Oncogene-evoked replication stress (RS) fuels genomic instability in diverse cancer types. Here we report that BRCA1, traditionally regarded a tumour suppressor, plays an unexpected tumour-promoting role in glioblastoma (GBM), safeguarding a protective response to supraphysiological RS levels. Hi...

  17. Replication stress interferes with histone recycling and predeposition marking of new histones

    DEFF Research Database (Denmark)

    Jasencakova, Zuzana; Scharf, Annette N D; Ask, Katrine

    2010-01-01

    To restore chromatin on new DNA during replication, recycling of histones evicted ahead of the fork is combined with new histone deposition. The Asf1 histone chaperone, which buffers excess histones under stress, is a key player in this process. Yet how histones handled by human Asf1 are modified...

  18. Bid protects the mouse hematopoietic system following hydroxyurea-induced replicative stress.

    Science.gov (United States)

    Liu, Y; Aiello, A; Zinkel, S S

    2012-10-01

    Hematopoietic stem cells (HSCs) possess long-term self-renewal capacity and multipotent differentiative capacity, to maintain the hematopoietic system. Long-term hematopoietic homeostasis requires effective control of genotoxic damage to maintain HSC function and prevent propagation of deleterious mutations. Here we investigate the role of the BH3-only Bcl-2 family member Bid in the response of murine hematopoietic cells to long-term replicative stress induced by hydroxyurea (HU). The PI3-like serine/threonine kinase, ATR, initiates the DNA damage response (DDR) to replicative stress. The pro-apoptotic Bcl-2 family member, Bid, facilitates this response to replicative stress in hematopoietic cells, but the in vivo role of this DDR function of Bid has not been defined. Surprisingly, we demonstrate that long-term HU treatment expands wild-type myeloid progenitor cells (MPCs) and HSC-enriched Lin(-)Sca1(+)Kit(+) (LSK) cells to maintain bone marrow function as measured by long-term competitive repopulating ability. Bid-/- MPCs demonstrate increased sensitivity to HU and are depleted. Bid-/- LSK cells demonstrate increased mobilization manifest by increased Bromodeoxyuridine (BrdU) incorporation. Bid-/- MPCs and LSK cells are relatively depleted, however, and bone marrow from Bid-/- mice demonstrates decreased long-term competitive repopulating ability in both primary and secondary transplants. We thus describe a survival function of Bid in hematopoiesis in the setting of chronic replicative stress.

  19. BRCA1-regulated RRM2 expression protects glioblastoma cells from endogenous replication stress and promotes tumorigenicity

    DEFF Research Database (Denmark)

    Rasmussen, Rikke D.; Gajjar, Madhavsai K.; Tuckova, Lucie

    2016-01-01

    Oncogene-evoked replication stress (RS) fuels genomic instability in diverse cancer types. Here we report that BRCA1, traditionally regarded a tumour suppressor, plays an unexpected tumour-promoting role in glioblastoma (GBM), safeguarding a protective response to supraphysiological RS levels...

  20. HERP Binds TBK1 To Activate Innate Immunity and Repress Virus Replication in Response to Endoplasmic Reticulum Stress.

    Science.gov (United States)

    Ge, Maolin; Luo, Zhen; Qiao, Zhi; Zhou, Yao; Cheng, Xin; Geng, Qibin; Cai, Yanyan; Wan, Pin; Xiong, Ying; Liu, Fang; Wu, Kailang; Liu, Yingle; Wu, Jianguo

    2017-09-27

    Host innate immunity is crucial for cellular responses against viral infection sensed by distinct pattern recognition receptors and endoplasmic reticulum (ER) stress. Enterovirus 71 (EV71) is a causative agent of hand, foot, and mouth disease and neurological diseases. However, the exact mechanism underlying the link between ER stress induced by EV71 infection and host innate immunity is largely unknown. In this study, we demonstrated that EV71 infection induces the homocysteine-induced ER protein (HERP), a modulator of the ER stress response which is dependent on the participation of MAVS. Virus-induced HERP subsequently stimulates host innate immunity to repress viral replication by promoting type-I IFNs (IFN-α and IFN-β) and type-III IFN (IFN-λ1) expression. Through interacting with TANK-binding kinase 1, HERP amplifies the MAVS signaling and facilitates the phosphorylation and nuclear translocation of IFN regulatory factor 3 and NF-κB to enhance the expression of IFNs, which leads to a broad inhibition of the replication of RNA viruses, including EV71, Sendai virus, influenza A virus, and vesicular stomatitis virus. Therefore, we demonstrated that HERP plays an important role in the regulation of host innate immunity in response to ER stress during the infection of RNA viruses. These findings provide new insights into the mechanism underlying the replication of RNA viruses and the production of IFNs, and also demonstrate a new role of HERP in the regulation of host innate immunity in response to viral infection. Copyright © 2017 by The American Association of Immunologists, Inc.

  1. Signaling from Mus81-Eme2-Dependent DNA Damage Elicited by Chk1 Deficiency Modulates Replication Fork Speed and Origin Usage

    Directory of Open Access Journals (Sweden)

    Hervé Técher

    2016-02-01

    Full Text Available Mammalian cells deficient in ATR or Chk1 display moderate replication fork slowing and increased initiation density, but the underlying mechanisms have remained unclear. We show that exogenous deoxyribonucleosides suppress both replication phenotypes in Chk1-deficient, but not ATR-deficient, cells. Thus, in the absence of exogenous stress, depletion of either protein impacts the replication dynamics through different mechanisms. In addition, Chk1 deficiency, but not ATR deficiency, triggers nuclease-dependent DNA damage. Avoiding damage formation through invalidation of Mus81-Eme2 and Mre11, or preventing damage signaling by turning off the ATM pathway, suppresses the replication phenotypes of Chk1-deficient cells. Damage and resulting DDR activation are therefore the cause, not the consequence, of replication dynamics modulation in these cells. Together, we identify moderate reduction of precursors available for replication as an additional outcome of DDR activation. We propose that resulting fork slowing, and subsequent firing of backup origins, helps replication to proceed along damaged templates.

  2. The MMS22L-TONSL complex mediates recovery from replication stress and homologous recombination.

    Science.gov (United States)

    O'Donnell, Lara; Panier, Stephanie; Wildenhain, Jan; Tkach, Johnny M; Al-Hakim, Abdallah; Landry, Marie-Claude; Escribano-Diaz, Cristina; Szilard, Rachel K; Young, Jordan T F; Munro, Meagan; Canny, Marella D; Kolas, Nadine K; Zhang, Wei; Harding, Shane M; Ylanko, Jarkko; Mendez, Megan; Mullin, Michael; Sun, Thomas; Habermann, Bianca; Datti, Alessandro; Bristow, Robert G; Gingras, Anne-Claude; Tyers, Michael D; Brown, Grant W; Durocher, Daniel

    2010-11-24

    Genome integrity is jeopardized each time DNA replication forks stall or collapse. Here we report the identification of a complex composed of MMS22L (C6ORF167) and TONSL (NFKBIL2) that participates in the recovery from replication stress. MMS22L and TONSL are homologous to yeast Mms22 and plant Tonsoku/Brushy1, respectively. MMS22L-TONSL accumulates at regions of ssDNA associated with distressed replication forks or at processed DNA breaks, and its depletion results in high levels of endogenous DNA double-strand breaks caused by an inability to complete DNA synthesis after replication fork collapse. Moreover, cells depleted of MMS22L are highly sensitive to camptothecin, a topoisomerase I poison that impairs DNA replication progression. Finally, MMS22L and TONSL are necessary for the efficient formation of RAD51 foci after DNA damage, and their depletion impairs homologous recombination. These results indicate that MMS22L and TONSL are genome caretakers that stimulate the recombination-dependent repair of stalled or collapsed replication forks. Copyright © 2010 Elsevier Inc. All rights reserved.

  3. Persistent Amplification of DNA Damage Signal Involved in Replicative Senescence of Normal Human Diploid Fibroblasts

    Directory of Open Access Journals (Sweden)

    Masatoshi Suzuki

    2012-01-01

    Full Text Available Foci of phosphorylated histone H2AX and ATM are the surrogate markers of DNA double strand breaks. We previously reported that the residual foci increased their size after irradiation, which amplifies DNA damage signals. Here, we addressed whether amplification of DNA damage signal is involved in replicative senescence of normal human diploid fibroblasts. Large phosphorylated H2AX foci (>1.5 μm diameter were specifically detected in presenescent cells. The frequency of cells with large foci was well correlated with that of cells positive for senescence-associated β-galactosidase staining. Hypoxic cell culture condition extended replicative life span of normal human fibroblast, and we found that the formation of large foci delayed in those cells. Our immuno-FISH analysis revealed that large foci partially localized at telomeres in senescent cells. Importantly, large foci of phosphorylated H2AX were always colocalized with phosphorylated ATM foci. Furthermore, Ser15-phosphorylated p53 showed colocalization with the large foci. Since the treatment of senescent cells with phosphoinositide 3-kinase inhibitor, wortmannin, suppressed p53 phosphorylation, it is suggested that amplification of DNA damage signaling sustains persistent activation of ATM-p53 pathway, which is essential for replicative senescence.

  4. Oxidative stress and stress signaling: menace of diabetic cardiomyopathy

    Institute of Scientific and Technical Information of China (English)

    Loren E WOLD; Asli F CEYLAN-ISIK; Jun REN

    2005-01-01

    Cardiovascular disease is the most common cause of death in the diabetic population and is currently one of the leading causes of death in the United States and other industrialized countries. The health care expenses associated with cardiovascular disease are staggering, reaching more than US$350 billion in 2003. The risk factors for cardiovascular disease include high fat/cholesterol levels,alcoholism, smoking, genetics, environmental factors and hypertension, which are commonly used to gauge an individual's risk of cardiovascular disease and to track their progress during therapy. Most recently, these factors have become important in the early prevention of cardiovascular diseases. Oxidative stress, the imbalance between reactive oxygen species production and breakdown by endogenous antioxidants, has been implicated in the onset and progression of cardiovascular diseases such as congestive heart failure and diabetes-associated heart dysfunction (diabetic cardiomyopathy). Antioxidant therapy has shown promise in preventing the development of diabetic heart complications. This review focuses on recent advances in oxidative stress theory and antioxidant therapy in diabetic cardiomyopathy, with an emphasis on the stress signaling pathways hypothesized to be involved. Many of these stress signaling pathways lead to activation of reactive oxygen species, major players in the development and progression of diabetic cardiomyopathy.

  5. Human PIF1 helicase supports DNA replication and cell growth under oncogenic-stress

    OpenAIRE

    2014-01-01

    Unwinding duplex DNA is a critical processing step during replication, repair and transcription. Pif1 are highly conserved non-processive 5′->3′ DNA helicases with well-established roles in maintenance of yeast genome stability. However, the function of the sole member of Pif1 family in humans remains unclear. Human PIF1 is essential for tumour cell viability, particularly during replication stress, but is dispensable in non-cancerous cells and Pif1 deficient mice. Here we report that suppres...

  6. Dynamic Association of the Replication Initiator and Transcription Factor DnaA with the Bacillus subtilis Chromosome during Replication Stress

    OpenAIRE

    2008-01-01

    DnaA functions as both a transcription factor and the replication initiator in bacteria. We characterized the DNA binding dynamics of DnaA on a genomic level. Based on cross-linking and chromatin immunoprecipitation data, DnaA binds at least 17 loci, 15 of which are regulated transcriptionally in response to inhibition of replication (replication stress). Six loci, each of which has a cluster of at least nine potential DnaA binding sites, had significant increases in binding by DnaA when repl...

  7. Are Luxury Brand Labels and "Green" Labels Costly Signals of Social Status? An Extended Replication.

    Science.gov (United States)

    Berger, Joël

    2017-01-01

    Costly signaling theory provides an explanation for why humans are willing to a pay a premium for conspicuous products such as luxury brand-labeled clothing or conspicuous environmentally friendly cars. According to the theory, the extra cost of such products is a signal of social status and wealth and leads to advantages in social interactions for the signaler. A previous study found positive evidence for the case of luxury brand labels. However, an issue of this study was that some of the experiments were not conducted in a perfectly double-blind manner. I resolved this by replicating variations of the original design in a double-blind procedure. Additionally, besides the luxury label condition, I introduced a "green" label condition. Thus, the hypothesis that signaling theory is able to explain pro-environmental behavior was tested for the first time in a natural field setting. Further, I conducted experiments in both average and below-average socioeconomic neighborhoods, where, according to signaling theory, the effects of luxury signals should be even stronger. In contrast to the original study, I did not find positive effects of the luxury brand label in any of the five experiments. Nor did I find evidence for a green-signaling effect. Moreover, in poor neighborhoods a negative tendency of the luxury label actually became evident. This suggests that a signaling theory explanation of costly labels must take into account the characteristics of the observers, e.g. their social status.

  8. Utilizing ras signaling pathway to direct selective replication of herpes simplex virus-1.

    Directory of Open Access Journals (Sweden)

    Weihong Pan

    Full Text Available Re-engineering the tropism of viruses is an attractive translational strategy for targeting cancer cells. The Ras signal transduction pathway is a central hub for a variety of pro-oncogenic events with a fundamental role in normal and neoplastic physiology. In this work we were interested in linking Ras activation to HSV-1 replication in a direct manner in order to generate a novel oncolytic herpes virus which can target cancer cells. To establish such link, we developed a mutant HSV-1 in which the expression of ICP4 (infected cell protein-4, a viral protein necessary for replication is controlled by activation of ELK, a transcription factor down-stream of the Ras pathway and mainly activated by ERK (extracellular signal-regulated kinase, an important Ras effector pathway. This mutant HSV-1 was named as Signal-Smart 1 (SS1. A series of prostate cells were infected with the SS1 virus. Cells with elevated levels of ELK activation were preferentially infected by the SS1 virus, as demonstrated by increased levels of viral progeny, herpetic glycoprotein C and overall SS1 viral protein production. Upon exposure to SS1, the proliferation, invasiveness and colony formation capabilities of prostate cancer cells with increased ELK activation were significantly decreased (p<0.05, while the rate of apoptosis/necrosis in these cells was increased. Additionally, high Ras signaling cells infected with SS1 showed a prominent arrest in the G1 phase of the cell cycle as compared to cells exposed to parental HSV-1. The results of this study reveal the potential for re-modeling the host-herpes interaction to specifically interfere with the life of cancer cells with increased Ras signaling. SS1 also serves as a "prototype" for development of a family of signal-smart viruses which can target cancer cells on the basis of their signaling portfolio.

  9. Oncogenic Herpesvirus Utilizes Stress-Induced Cell Cycle Checkpoints for Efficient Lytic Replication.

    Directory of Open Access Journals (Sweden)

    Giuseppe Balistreri

    2016-02-01

    Full Text Available Kaposi's sarcoma herpesvirus (KSHV causes Kaposi's sarcoma and certain lymphoproliferative malignancies. Latent infection is established in the majority of tumor cells, whereas lytic replication is reactivated in a small fraction of cells, which is important for both virus spread and disease progression. A siRNA screen for novel regulators of KSHV reactivation identified the E3 ubiquitin ligase MDM2 as a negative regulator of viral reactivation. Depletion of MDM2, a repressor of p53, favored efficient activation of the viral lytic transcription program and viral reactivation. During lytic replication cells activated a p53 response, accumulated DNA damage and arrested at G2-phase. Depletion of p21, a p53 target gene, restored cell cycle progression and thereby impaired the virus reactivation cascade delaying the onset of virus replication induced cytopathic effect. Herpesviruses are known to reactivate in response to different kinds of stress, and our study now highlights the molecular events in the stressed host cell that KSHV has evolved to utilize to ensure efficient viral lytic replication.

  10. Oncogenic Herpesvirus Utilizes Stress-Induced Cell Cycle Checkpoints for Efficient Lytic Replication.

    Science.gov (United States)

    Balistreri, Giuseppe; Viiliäinen, Johanna; Turunen, Mikko; Diaz, Raquel; Lyly, Lauri; Pekkonen, Pirita; Rantala, Juha; Ojala, Krista; Sarek, Grzegorz; Teesalu, Mari; Denisova, Oxana; Peltonen, Karita; Julkunen, Ilkka; Varjosalo, Markku; Kainov, Denis; Kallioniemi, Olli; Laiho, Marikki; Taipale, Jussi; Hautaniemi, Sampsa; Ojala, Päivi M

    2016-02-01

    Kaposi's sarcoma herpesvirus (KSHV) causes Kaposi's sarcoma and certain lymphoproliferative malignancies. Latent infection is established in the majority of tumor cells, whereas lytic replication is reactivated in a small fraction of cells, which is important for both virus spread and disease progression. A siRNA screen for novel regulators of KSHV reactivation identified the E3 ubiquitin ligase MDM2 as a negative regulator of viral reactivation. Depletion of MDM2, a repressor of p53, favored efficient activation of the viral lytic transcription program and viral reactivation. During lytic replication cells activated a p53 response, accumulated DNA damage and arrested at G2-phase. Depletion of p21, a p53 target gene, restored cell cycle progression and thereby impaired the virus reactivation cascade delaying the onset of virus replication induced cytopathic effect. Herpesviruses are known to reactivate in response to different kinds of stress, and our study now highlights the molecular events in the stressed host cell that KSHV has evolved to utilize to ensure efficient viral lytic replication.

  11. DNA Lesions Induced by Replication Stress Trigger Mitotic Aberration and Tetraploidy Development

    Science.gov (United States)

    Ichijima, Yosuke; Yoshioka, Ken-ichi; Yoshioka, Yoshiko; Shinohe, Keitaro; Fujimori, Hiroaki; Unno, Junya; Takagi, Masatoshi; Goto, Hidemasa; Inagaki, Masaki; Mizutani, Shuki; Teraoka, Hirobumi

    2010-01-01

    During tumorigenesis, cells acquire immortality in association with the development of genomic instability. However, it is still elusive how genomic instability spontaneously generates during the process of tumorigenesis. Here, we show that precancerous DNA lesions induced by oncogene acceleration, which induce situations identical to the initial stages of cancer development, trigger tetraploidy/aneuploidy generation in association with mitotic aberration. Although oncogene acceleration primarily induces DNA replication stress and the resulting lesions in the S phase, these lesions are carried over into the M phase and cause cytokinesis failure and genomic instability. Unlike directly induced DNA double-strand breaks, DNA replication stress-associated lesions are cryptogenic and pass through cell-cycle checkpoints due to limited and ineffective activation of checkpoint factors. Furthermore, since damaged M-phase cells still progress in mitotic steps, these cells result in chromosomal mis-segregation, cytokinesis failure and the resulting tetraploidy generation. Thus, our results reveal a process of genomic instability generation triggered by precancerous DNA replication stress. PMID:20098673

  12. DNA lesions induced by replication stress trigger mitotic aberration and tetraploidy development.

    Directory of Open Access Journals (Sweden)

    Yosuke Ichijima

    Full Text Available During tumorigenesis, cells acquire immortality in association with the development of genomic instability. However, it is still elusive how genomic instability spontaneously generates during the process of tumorigenesis. Here, we show that precancerous DNA lesions induced by oncogene acceleration, which induce situations identical to the initial stages of cancer development, trigger tetraploidy/aneuploidy generation in association with mitotic aberration. Although oncogene acceleration primarily induces DNA replication stress and the resulting lesions in the S phase, these lesions are carried over into the M phase and cause cytokinesis failure and genomic instability. Unlike directly induced DNA double-strand breaks, DNA replication stress-associated lesions are cryptogenic and pass through cell-cycle checkpoints due to limited and ineffective activation of checkpoint factors. Furthermore, since damaged M-phase cells still progress in mitotic steps, these cells result in chromosomal mis-segregation, cytokinesis failure and the resulting tetraploidy generation. Thus, our results reveal a process of genomic instability generation triggered by precancerous DNA replication stress.

  13. Slx5/Slx8 Promotes Replication Stress Tolerance by Facilitating Mitotic Progression

    Directory of Open Access Journals (Sweden)

    Yee Mon Thu

    2016-05-01

    Full Text Available Loss of minichromosome maintenance protein 10 (Mcm10 causes replication stress. We uncovered that S. cerevisiae mcm10-1 mutants rely on the E3 SUMO ligase Mms21 and the SUMO-targeted ubiquitin ligase complex Slx5/8 for survival. Using quantitative mass spectrometry, we identified changes in the SUMO proteome of mcm10-1 mutants and revealed candidates regulated by Slx5/8. Such candidates included subunits of the chromosome passenger complex (CPC, Bir1 and Sli15, known to facilitate spindle assembly checkpoint (SAC activation. We show here that Slx5 counteracts SAC activation in mcm10-1 mutants under conditions of moderate replication stress. This coincides with the proteasomal degradation of sumoylated Bir1. Importantly, Slx5-dependent mitotic relief was triggered not only by Mcm10 deficiency but also by treatment with low doses of the alkylating drug methyl methanesulfonate. Based on these findings, we propose a model in which Slx5/8 allows for passage through mitosis when replication stress is tolerable.

  14. p53 induces formation of NEAT1 lncRNA-containing paraspeckles that modulate replication stress response and chemosensitivity.

    Science.gov (United States)

    Adriaens, Carmen; Standaert, Laura; Barra, Jasmine; Latil, Mathilde; Verfaillie, Annelien; Kalev, Peter; Boeckx, Bram; Wijnhoven, Paul W G; Radaelli, Enrico; Vermi, William; Leucci, Eleonora; Lapouge, Gaëlle; Beck, Benjamin; van den Oord, Joost; Nakagawa, Shinichi; Hirose, Tetsuro; Sablina, Anna A; Lambrechts, Diether; Aerts, Stein; Blanpain, Cédric; Marine, Jean-Christophe

    2016-08-01

    In a search for mediators of the p53 tumor suppressor pathway, which induces pleiotropic and often antagonistic cellular responses, we identified the long noncoding RNA (lncRNA) NEAT1. NEAT1 is an essential architectural component of paraspeckle nuclear bodies, whose pathophysiological relevance remains unclear. Activation of p53, pharmacologically or by oncogene-induced replication stress, stimulated the formation of paraspeckles in mouse and human cells. Silencing Neat1 expression in mice, which prevents paraspeckle formation, sensitized preneoplastic cells to DNA-damage-induced cell death and impaired skin tumorigenesis. We provide mechanistic evidence that NEAT1 promotes ATR signaling in response to replication stress and is thereby engaged in a negative feedback loop that attenuates oncogene-dependent activation of p53. NEAT1 targeting in established human cancer cell lines induced synthetic lethality with genotoxic chemotherapeutics, including PARP inhibitors, and nongenotoxic activation of p53. This study establishes a key genetic link between NEAT1 paraspeckles, p53 biology and tumorigenesis and identifies NEAT1 as a promising target to enhance sensitivity of cancer cells to both chemotherapy and p53 reactivation therapy.

  15. Relationship between DNA damage response, initiated by camptothecin or oxidative stress, and DNA replication, analyzed by quantitative 3D image analysis.

    Science.gov (United States)

    Berniak, K; Rybak, P; Bernas, T; Zarębski, M; Biela, E; Zhao, H; Darzynkiewicz, Z; Dobrucki, J W

    2013-10-01

    A method of quantitative analysis of spatial (3D) relationship between discrete nuclear events detected by confocal microscopy is described and applied in analysis of a dependence between sites of DNA damage signaling (γH2AX foci) and DNA replication (EdU incorporation) in cells subjected to treatments with camptothecin (Cpt) or hydrogen peroxide (H2O2). Cpt induces γH2AX foci, likely reporting formation of DNA double-strand breaks (DSBs), almost exclusively at sites of DNA replication. This finding is consistent with the known mechanism of induction of DSBs by DNA topoisomerase I (topo1) inhibitors at the sites of collisions of the moving replication forks with topo1-DNA "cleavable complexes" stabilized by Cpt. Whereas an increased level of H2AX histone phosphorylation is seen in S-phase of cells subjected to H2O2, only a minor proportion of γH2AX foci coincide with DNA replication sites. Thus, the increased level of H2AX phosphorylation induced by H2O2 is not a direct consequence of formation of DNA lesions at the sites of moving DNA replication forks. These data suggest that oxidative stress induced by H2O2 and formation of the primary H2O2-induced lesions (8-oxo-7,8-dihydroguanosine) inhibits replication globally and triggers formation of γH2AX at various distances from replication forks. Quantitative analysis of a frequency of DNA replication sites and γH2AX foci suggests also that stalling of replicating forks by Cpt leads to activation of new DNA replication origins. © 2013 International Society for Advancement of Cytometry.

  16. Subversion of Host Responses to Energy Insufficiency by Us3 Supports Herpes Simplex Virus 1 Replication during Stress.

    Science.gov (United States)

    Vink, Elizabeth I; Smiley, James R; Mohr, Ian

    2017-07-15

    Cellular stress responses to energy insufficiency can impact virus reproduction. In particular, activation of the host AMP-activated protein kinase (AMPK) by low energy could limit protein synthesis by inhibiting mTORC1. Although many herpesviruses, including herpes simplex virus 1 (HSV-1), stimulate mTORC1, how HSV-1-infected cells respond to energy availability, a physiological indicator regulating mTORC1, has not been investigated. In addition, the impact of low-energy stress on productive HSV-1 growth and viral genetic determinants potentially enabling replication under physiological stress remains undefined. Here, we demonstrate that mTORC1 activity in HSV-1-infected cells is largely insensitive to stress induced by simulated energy insufficiency. Furthermore, resistance of mTORC1 activity to low-energy-induced stress, while not significantly influenced by the HSV-1 UL46-encoded phosphatidylinositol 3-kinase (PI3K)-Akt activator, was dependent upon the Ser/Thr kinase activity of Us3. A Us3-deficient virus was hypersensitive to low-energy-induced stress as infected cell protein synthesis and productive replication were reduced compared to levels in cells infected with a Us3-expressing virus. Although Us3 did not detectably prevent energy stress-induced AMPK activation, it enforced mTORC1 activation despite the presence of activated AMPK. In the absence of applied low-energy stress, AMPK activity in infected cells was restricted in a Us3-dependent manner. This establishes that the Us3 kinase not only activated mTORC1 but also enabled sustained mTORC1 signaling during simulated energy insufficiency that would otherwise restrict protein synthesis and virus replication. Moreover, it identifies the alphaherpesvirus-specific Us3 kinase as an mTORC1 activator that subverts the host cell energy-sensing program to support viral productive growth irrespective of physiological stress.IMPORTANCE Like all viruses, herpes simplex virus type 1 (HSV-1) reproduction relies upon

  17. A SELEX-screened aptamer of human hepatitis B virus RNA encapsidation signal suppresses viral replication.

    Directory of Open Access Journals (Sweden)

    Hui Feng

    Full Text Available BACKGROUND: The specific interaction between hepatitis B virus (HBV polymerase (P protein and the ε RNA stem-loop on pregenomic (pg RNA is crucial for viral replication. It triggers both pgRNA packaging and reverse transcription and thus represents an attractive antiviral target. RNA decoys mimicking ε in P protein binding but not supporting replication might represent novel HBV inhibitors. However, because generation of recombinant enzymatically active HBV polymerase is notoriously difficult, such decoys have as yet not been identified. METHODOLOGY/PRINCIPAL FINDINGS: Here we used a SELEX approach, based on a new in vitro reconstitution system exploiting a recombinant truncated HBV P protein (miniP, to identify potential ε decoys in two large ε RNA pools with randomized upper stem. Selection of strongly P protein binding RNAs correlated with an unexpected strong enrichment of A residues. Two aptamers, S6 and S9, displayed particularly high affinity and specificity for miniP in vitro, yet did not support viral replication when part of a complete HBV genome. Introducing S9 RNA into transiently HBV producing HepG2 cells strongly suppressed pgRNA packaging and DNA synthesis, indicating the S9 RNA can indeed act as an ε decoy that competitively inhibits P protein binding to the authentic ε signal on pgRNA. CONCLUSIONS/SIGNIFICANCE: This study demonstrates the first successful identification of human HBV ε aptamers by an in vitro SELEX approach. Effective suppression of HBV replication by the S9 aptamer provides proof-of-principle for the ability of ε decoy RNAs to interfere with viral P-ε complex formation and suggests that S9-like RNAs may further be developed into useful therapeutics against chronic hepatitis B.

  18. Emodin inhibits coxsackievirus B3 replication via multiple signalling cascades leading to suppression of translation.

    Science.gov (United States)

    Zhang, Huifang M; Wang, Fengping; Qiu, Ye; Ye, Xin; Hanson, Paul; Shen, Hongxing; Yang, Decheng

    2016-02-15

    CVB3 (coxsackievirus 3) is a primary causal agent of viral myocarditis. Emodin is a natural compound isolated from certain plant roots. In the present study, we found that emodin inhibited CVB3 replication in vitro and in mice, and now we report an unrecognized mechanism by which emodin inhibits CVB3 replication through suppression of viral protein translation via multiple pathways. On one hand, emodin treatment inhibited Akt/mTOR (mammalian target of rapamycin) signalling and activated 4EBP1 (eukaryotic initiation factor 4R-binding protein 1), leading to suppression of translation initiation of ribosomal protein L32 encoded by a 5'-TOP (terminal oligopyrimidine) mRNA. On the other hand, emodin treatment differentially regulated multiple signal cascades, including Akt/mTORC1/p70(S6K) (p70 S6 kinase), ERK1/2 (extracellular-signal-regulated kinase 1/2)/p90(RSK) (p90 ribosomal S6 kinase) and Ca(2+)/calmodulin, leading to activation of eEF2K (eukaryotic elongation factor 2 kinase) and subsequent inactivation of eEF2 (eukaryotic elongation factor 2), resulting in inhibition of CVB3 VP1 (viral protein 1) synthesis. These data imply that eEF2K is a major factor mediating cross-talk of different arms of signalling cascades in this signal network. This notion was verified by either overexpressing eEF2K or treating the cells with siRNAs or eEF2K inhibitor A484954. We showed further that the emodin-induced decrease in p70(S6K) phosphorylation plays a dominant positive role in activation of eEF2K and in turn in conferring the antiviral effect of emodin. This finding was further solidified by expressing constitutively active and dominant-negative Akt. Collectively, our data reveal that emodin inhibits viral replication through impairing translational machinery and suppression of viral translation elongation. © 2016 Authors; published by Portland Press Limited.

  19. The MluI cell cycle box (MCB) motifs, but not damage-responsive elements (DREs), are responsible for the transcriptional induction of the rhp51+ gene in response to DNA replication stress.

    Science.gov (United States)

    Sartagul, Wugangerile; Zhou, Xin; Yamada, Yuki; Ma, Ning; Tanaka, Katsunori; Furuyashiki, Tomoyuki; Ma, Yan

    2014-01-01

    DNA replication stress induces the transcriptional activation of rhp51+, a fission yeast recA homolog required for repair of DNA double strand breaks. However, the mechanism by which DNA replication stress activates rhp51+ transcription is not understood. The promoter region of rhp51+ contains two damage-responsive elements (DREs) and two MluI cell cycle box (MCB) motifs. Using luciferase reporter assays, we examined the role of these elements in rhp51+ transcription. The full-length rhp51+ promoter and a promoter fragment containing MCB motifs only, but not a fragment containing DREs, mediated transcriptional activation upon DNA replication stress. Removal of the MCB motifs from the rhp51+ promoter abolished the induction of rhp51+ transcription by DNA replication stress. Consistent with a role for MCB motifs in rhp51+ transcription activation, deletion of the MBF (MCB-binding factor) co-repressors Nrm1 and Yox1 precluded rhp51+ transcriptional induction in response to DNA replication stress. Using cells deficient in checkpoint signaling molecules, we found that the Rad3-Cds1/Chk1 pathway partially mediated rhp51+ transcription in response to DNA replication stress, suggesting the involvement of unidentified checkpoint signaling pathways. Because MBF is critical for G1/S transcription, we examined how the cell cycle affected rhp51+ transcription. The transcription of rhp51+ and cdc18+, an MBF-dependent G1/S gene, peaked simultaneously in synchronized cdc25-22 cells. Furthermore, DNA replication stress maintained transcription of rhp51+ similarly to cdc18+. Collectively, these results suggest that MBF and its regulators mediate rhp51+ transcription in response to DNA replication stress, and underlie rhp51+ transcription at the G1/S transition.

  20. Dormant origins licensed by excess Mcm2-7 are required for human cells to survive replicative stress.

    Science.gov (United States)

    Ge, Xin Quan; Jackson, Dean A; Blow, J Julian

    2007-12-15

    In late mitosis and early G1, Mcm2-7 complexes are loaded onto DNA to license replication origins for use in the upcoming S phase. However, the amount of Mcm2-7 loaded is in significant excess over the number of origins normally used. We show here that in human cells, excess chromatin-bound Mcm2-7 license dormant replication origins that do not fire during normal DNA replication, in part due to checkpoint activity. Dormant origins were activated within active replicon clusters if replication fork progression was inhibited, despite the activation of S-phase checkpoints. After lowering levels of chromatin-bound Mcm2-7 in human cells by RNA interference (RNAi), the use of dormant origins was suppressed in response to replicative stress. Although cells with lowered chromatin-bound Mcm2-7 replicated at normal rates, when challenged with replication inhibitors they had dramatically reduced rates of DNA synthesis and reduced viability. These results suggest that the use of dormant origins licensed by excess Mcm2-7 is a new and physiologically important mechanism that cells utilize to maintain DNA replication rates under conditions of replicative stress. We propose that checkpoint kinase activity can preferentially suppress initiation within inactive replicon clusters, thereby directing new initiation events toward active clusters that are experiencing replication problems.

  1. HIV-1 Nef control of cell signalling molecules: multiple strategies to promote virus replication

    Indian Academy of Sciences (India)

    Alison L Greenway; Gavan Holloway; Dale A McPhee; Phoebe Ellis; Alyssa Cornall; Michael Lidman

    2003-04-01

    HIV-1 has at its disposal numerous proteins encoded by its genome which provide the required arsenal to establish and maintain infection in its host for a considerable number of years. One of the most important and enigmatic of these proteins is Nef. The Nef protein of HIV-1 plays a fundamental role in the virus life cycle. This small protein of approximately 27 kDa is required for maximal virus replication and disease progression. The mechanisms by which it is able to act as a positive factor during virus replication is an area of intense research and although some controversy surrounds Nef much has been gauged as to how it functions. Its ability to modulate the expression of key cellular receptors important for cell activation and control signal transduction elements and events by interacting with numerous cellular kinases and signalling molecules, including members of the Src family kinases, leading to an effect on host cell function is likely to explain at least in part its role during infection and represents a finely tuned mechanism where this protein assists HIV-1 to control its host.

  2. Proteome-wide analysis of SUMO2 targets in response to pathological DNA replication stress in human cells

    DEFF Research Database (Denmark)

    Bursomanno, Sara; Beli, Petra; Khan, Asif M;

    2015-01-01

    SUMOylation is a form of post-translational modification involving covalent attachment of SUMO (Small Ubiquitin-like Modifier) polypeptides to specific lysine residues in the target protein. In human cells, there are four SUMO proteins, SUMO1-4, with SUMO2 and SUMO3 forming a closely related...... subfamily. SUMO2/3, in contrast to SUMO1, are predominantly involved in the cellular response to certain stresses, including heat shock. Substantial evidence from studies in yeast has shown that SUMOylation plays an important role in the regulation of DNA replication and repair. Here, we report a proteomic...... repair. We have also shown that deficiency of POLD3 leads to an increase in RPA-bound ssDNA when cells are under replication stress, suggesting that POLD3 plays a role in the cellular response to DNA replication stress. Considering that DNA replication stress is a source of genome instability...

  3. Chronic DNA Replication Stress Reduces Replicative Lifespan of Cells by TRP53-Dependent, microRNA-Assisted MCM2-7 Downregulation.

    Directory of Open Access Journals (Sweden)

    Gongshi Bai

    2016-01-01

    Full Text Available Circumstances that compromise efficient DNA replication, such as disruptions to replication fork progression, cause a state known as DNA replication stress (RS. Whereas normally proliferating cells experience low levels of RS, excessive RS from intrinsic or extrinsic sources can trigger cell cycle arrest and senescence. Here, we report that a key driver of RS-induced senescence is active downregulation of the Minichromosome Maintenance 2-7 (MCM2-7 factors that are essential for replication origin licensing and which constitute the replicative helicase core. Proliferating cells produce high levels of MCM2-7 that enable formation of dormant origins that can be activated in response to acute, experimentally-induced RS. However, little is known about how physiological RS levels impact MCM2-7 regulation. We found that chronic exposure of primary mouse embryonic fibroblasts (MEFs to either genetically-encoded or environmentally-induced RS triggered gradual MCM2-7 repression, followed by inhibition of replication and senescence that could be accelerated by MCM hemizygosity. The MCM2-7 reduction in response to RS is TRP53-dependent, and involves a group of Trp53-dependent miRNAs, including the miR-34 family, that repress MCM expression in replication-stressed cells before they undergo terminal cell cycle arrest. miR-34 ablation partially rescued MCM2-7 downregulation and genomic instability in mice with endogenous RS. Together, these data demonstrate that active MCM2-7 repression is a physiologically important mechanism for RS-induced cell cycle arrest and genome maintenance on an organismal level.

  4. Alpha thalassemia/mental retardation syndrome X-linked gene product ATRX is required for proper replication restart and cellular resistance to replication stress.

    Science.gov (United States)

    Leung, Justin Wai-Chung; Ghosal, Gargi; Wang, Wenqi; Shen, Xi; Wang, Jiadong; Li, Lei; Chen, Junjie

    2013-03-01

    Alpha thalassemia/mental retardation syndrome X-linked (ATRX) is a member of the SWI/SNF protein family of DNA-dependent ATPases. It functions as a chromatin remodeler and is classified as an SNF2-like helicase. Here, we showed somatic knock-out of ATRX displayed perturbed S-phase progression as well as hypersensitivity to replication stress. ATRX is recruited to sites of DNA damage, required for efficient checkpoint activation and faithful replication restart. In addition, we identified ATRX as a binding partner of MRE11-RAD50-NBS1 (MRN) complex. Together, these results suggest a non-canonical function of ATRX in guarding genomic stability.

  5. Proteome-wide analysis of SUMO2 targets in response to pathological DNA replication stress in human cells.

    Science.gov (United States)

    Bursomanno, Sara; Beli, Petra; Khan, Asif M; Minocherhomji, Sheroy; Wagner, Sebastian A; Bekker-Jensen, Simon; Mailand, Niels; Choudhary, Chunaram; Hickson, Ian D; Liu, Ying

    2015-01-01

    SUMOylation is a form of post-translational modification involving covalent attachment of SUMO (Small Ubiquitin-like Modifier) polypeptides to specific lysine residues in the target protein. In human cells, there are four SUMO proteins, SUMO1-4, with SUMO2 and SUMO3 forming a closely related subfamily. SUMO2/3, in contrast to SUMO1, are predominantly involved in the cellular response to certain stresses, including heat shock. Substantial evidence from studies in yeast has shown that SUMOylation plays an important role in the regulation of DNA replication and repair. Here, we report a proteomic analysis of proteins modified by SUMO2 in response to DNA replication stress in S phase in human cells. We have identified a panel of 22 SUMO2 targets with increased SUMOylation during DNA replication stress, many of which play key functions within the DNA replication machinery and/or in the cellular response to DNA damage. Interestingly, POLD3 was found modified most significantly in response to a low dose aphidicolin treatment protocol that promotes common fragile site (CFS) breakage. POLD3 is the human ortholog of POL32 in budding yeast, and has been shown to act during break-induced recombinational repair. We have also shown that deficiency of POLD3 leads to an increase in RPA-bound ssDNA when cells are under replication stress, suggesting that POLD3 plays a role in the cellular response to DNA replication stress. Considering that DNA replication stress is a source of genome instability, and that excessive replication stress is a hallmark of pre-neoplastic and tumor cells, our characterization of SUMO2 targets during a perturbed S-phase should provide a valuable resource for future functional studies in the fields of DNA metabolism and cancer biology.

  6. Visualization of mitochondrial DNA replication in individual cells by EdU signal amplification.

    Science.gov (United States)

    Haines, Kristine M; Feldman, Eva L; Lentz, Stephen I

    2010-11-15

    Mitochondria are key regulators of cellular energy and mitochondrial biogenesis is an essential component of regulating mitochondria numbers in healthy cells. One approach for monitoring mitochondrial biogenesis is to measure the rate of mitochondrial DNA (mtDNA) replication. We developed a sensitive technique to label newly synthesized mtDNA in individual cells in order to study mtDNA biogenesis. The technique combines the incorporation of 5-ethynyl-2'-deoxyuridine (EdU) with a tyramide signal amplification (TSA) protocol to visualize mtDNA replication within subcellular compartments of neurons. EdU is superior to other thymidine analogs, such as 5-bromo-2-deoxyuridine (BrdU), because the initial click reaction to label EdU does not require the harsh acid treatments or enzyme digests that are required for exposing the BrdU epitope. The milder labeling of EdU allows for direct comparison of its incorporation with other cellular markers. The ability to visualize and quantify mtDNA biogenesis provides an essential tool for investigating the mechanisms used to regulate mitochondrial biogenesis and would provide insight into the pathogenesis associated with drug toxicity, aging, cancer and neurodegenerative diseases. Our technique is applicable to sensory neurons as well as other cell types. The use of this technique to measure mtDNA biogenesis has significant implications in furthering the understanding of both normal cellular physiology as well as impaired disease states.

  7. XRN2 Links Transcription Termination to DNA Damage and Replication Stress.

    Directory of Open Access Journals (Sweden)

    Julio C Morales

    2016-07-01

    Full Text Available XRN2 is a 5'-3' exoribonuclease implicated in transcription termination. Here we demonstrate an unexpected role for XRN2 in the DNA damage response involving resolution of R-loop structures and prevention of DNA double-strand breaks (DSBs. We show that XRN2 undergoes DNA damage-inducible nuclear re-localization, co-localizing with 53BP1 and R loops, in a transcription and R-loop-dependent process. XRN2 loss leads to increased R loops, genomic instability, replication stress, DSBs and hypersensitivity of cells to various DNA damaging agents. We demonstrate that the DSBs that arise with XRN2 loss occur at transcriptional pause sites. XRN2-deficient cells also exhibited an R-loop- and transcription-dependent delay in DSB repair after ionizing radiation, suggesting a novel role for XRN2 in R-loop resolution, suppression of replication stress, and maintenance of genomic stability. Our study highlights the importance of regulating transcription-related activities as a critical component in maintaining genetic stability.

  8. XRN2 Links Transcription Termination to DNA Damage and Replication Stress.

    Science.gov (United States)

    Morales, Julio C; Richard, Patricia; Patidar, Praveen L; Motea, Edward A; Dang, Tuyen T; Manley, James L; Boothman, David A

    2016-07-01

    XRN2 is a 5'-3' exoribonuclease implicated in transcription termination. Here we demonstrate an unexpected role for XRN2 in the DNA damage response involving resolution of R-loop structures and prevention of DNA double-strand breaks (DSBs). We show that XRN2 undergoes DNA damage-inducible nuclear re-localization, co-localizing with 53BP1 and R loops, in a transcription and R-loop-dependent process. XRN2 loss leads to increased R loops, genomic instability, replication stress, DSBs and hypersensitivity of cells to various DNA damaging agents. We demonstrate that the DSBs that arise with XRN2 loss occur at transcriptional pause sites. XRN2-deficient cells also exhibited an R-loop- and transcription-dependent delay in DSB repair after ionizing radiation, suggesting a novel role for XRN2 in R-loop resolution, suppression of replication stress, and maintenance of genomic stability. Our study highlights the importance of regulating transcription-related activities as a critical component in maintaining genetic stability.

  9. Replication stress and mitotic dysfunction in cells expressing simian virus 40 large T antigen.

    Science.gov (United States)

    Hu, Liang; Filippakis, Harilaos; Huang, Haomin; Yen, Timothy J; Gjoerup, Ole V

    2013-12-01

    We previously demonstrated that simian virus 40 (SV40) large T antigen (LT) binds to the Bub1 kinase, a key regulator of the spindle checkpoint and chromosome segregation. Bub1 mutations or altered expression patterns are linked to chromosome missegregation and are considered to be a driving force in some human cancers. Here we report that LT, dependent on Bub1 binding, causes micronuclei, lagging chromatin, and anaphase bridges, which are hallmarks of chromosomal instability (CIN) and Bub1 insufficiency. Using time-lapse microscopy, we demonstrate that LT imposes a Bub1 binding-dependent delay in the metaphase-to-anaphase transition. Kinetochore fibers reveal that LT, via Bub1 binding, causes aberrant kinetochore (KT)-microtubule (MT) attachments and a shortened interkinetochore distance, consistent with a lack of tension. Previously, we showed that LT also induces the DNA damage response (DDR) via Bub1 binding. Using inducible LT cell lines, we show that an activated DDR was observed before the appearance of anaphase bridges and micronuclei. Furthermore, LT induction in serum-starved cells demonstrated γ-H2AX accumulation in cells that had not yet entered mitosis. Thus, DDR activation can occur independently of chromosome segregation defects. Replication stress pathways may be responsible, because signatures of replication stress were observed, which were attenuated by exogenous supplementation with nucleosides. Our observations allow us to propose a model that explains and integrates the diverse manifestations of genomic instability induced by LT.

  10. Analysis of spatial correlations between patterns of DNA damage response and DNA replication in nuclei of cells subjected to replication stress or oxidative damage.

    Science.gov (United States)

    Bernas, Tytus; Berniak, Krzysztof; Rybak, Paulina; Zarębski, Mirosław; Zhao, Hong; Darzynkiewicz, Zbigniew; Dobrucki, Jerzy W

    2013-10-01

    Sites of DNA replication (EdU incorporation) and DNA damage signaling (γH2AX) induced by camptothecin (Cpt) or hydrogen peroxide (H2O2) form characteristic patterns of foci in cell nuclei. The overlap between these patterns is a function of the number of DNA double strand breaks (DSBs) formed in replication sites. The goal of this study was to optimize a method of quantitative assessment of a degree of correlation between these two patterns. Such a correlation can be used to estimate a probability of inducing damage in sections of replicating DNA. The damage and replication foci are imaged in 3D with confocal microscopy and their respective positions within nuclei are determined with adaptive image segmentation. Using correlation functions spatial proximity of the resultant point patterns is quantified over the range of distances in cells in early-, mid- and late S-phase. As the numbers (and nuclear densities) of γH2AX and replication foci differ significantly in the subsequent substages of S phase, the detected association values were corrected for the expected random overlap between both classes of foci. Thus, the probability of their nonrandom association was estimated. Moreover, self association (clustering) of DNA replication sites in different stages of S-phase of the cell cycle was detected and accounted for. While the analysis revealed a strong correlation between the γH2AX foci and the sites of DNA replication in cells treated with Cpt, only a low correlation was apparent in cells exposed to H2O2. © 2013 International Society for Advancement of Cytometry.

  11. Adapting the Stress Response: Viral Subversion of the mTOR Signaling Pathway.

    Science.gov (United States)

    Le Sage, Valerie; Cinti, Alessandro; Amorim, Raquel; Mouland, Andrew J

    2016-05-24

    The mammalian target of rapamycin (mTOR) is a central regulator of gene expression, translation and various metabolic processes. Multiple extracellular (growth factors) and intracellular (energy status) molecular signals as well as a variety of stressors are integrated into the mTOR pathway. Viral infection is a significant stress that can activate, reduce or even suppress the mTOR signaling pathway. Consequently, viruses have evolved a plethora of different mechanisms to attack and co-opt the mTOR pathway in order to make the host cell a hospitable environment for replication. A more comprehensive knowledge of different viral interactions may provide fruitful targets for new antiviral drugs.

  12. Stress regulates endocannabinoid-CB1 receptor signaling.

    Science.gov (United States)

    Hillard, Cecilia J

    2014-10-01

    The CB1 cannabinoid receptor is a G protein coupled receptor that is widely expressed throughout the brain. The endogenous ligands for the CB1 receptor (endocannabinoids) are N-arachidonylethanolamine and 2-arachidonoylglycerol; together the endocannabinoids and CB1R subserve activity dependent, retrograde inhibition of neurotransmitter release in the brain. Deficiency of CB1 receptor signaling is associated with anhedonia, anxiety, and persistence of negative memories. CB1 receptor-endocannabinoid signaling is activated by stress and functions to buffer or dampen the behavioral and endocrine effects of acute stress. Its role in regulation of neuronal responses is more complex. Chronic variable stress exposure reduces endocannabinoid-CB1 receptor signaling and it is hypothesized that the resultant deficiency in endocannabinoid signaling contributes to the negative consequences of chronic stress. On the other hand, repeated exposure to the same stress can sensitize CB1 receptor signaling, resulting in dampening of the stress response. Data are reviewed that support the hypothesis that CB1 receptor signaling is stress responsive and that maintaining robust endocannabinoid/CB1 receptor signaling provides resilience against the development of stress-related pathologies.

  13. Pharmacological manipulation of the akt signaling pathway regulates myxoma virus replication and tropism in human cancer cells.

    Science.gov (United States)

    Werden, Steven J; McFadden, Grant

    2010-04-01

    Viruses have evolved an assortment of mechanisms for regulating the Akt signaling pathway to establish a cellular environment more favorable for viral replication. Myxoma virus (MYXV) is a rabbit-specific poxvirus that encodes many immunomodulatory factors, including an ankyrin repeat-containing host range protein termed M-T5 that functions to regulate tropism of MYXV for rabbit lymphocytes and certain human cancer cells. MYXV permissiveness in these human cancer cells is dependent upon the direct interaction between M-T5 and Akt, which has been shown to induce the kinase activity of Akt. In this study, an array of compounds that selectively manipulate Akt signaling was screened and we show that only a subset of Akt inhibitors significantly decreased the ability of MYXV to replicate in previously permissive human cancer cells. Furthermore, reduced viral replication efficiency was correlated with lower levels of phosphorylated Akt. In contrast, the PP2A-specific phosphatase inhibitor okadaic acid promoted increased Akt kinase activation and rescued MYXV replication in human cancer cells that did not previously support viral replication. Finally, phosphorylation of Akt at residue Thr308 was shown to dictate the physical interaction between Akt and M-T5, which then leads to phosphorylation of Ser473 and permits productive MYXV replication in these human cancer cells. The results of this study further characterize the mechanism by which M-T5 exploits the Akt signaling cascade and affirms this interaction as a major tropism determinant that regulates the replication efficiency of MYXV in human cancer cells.

  14. Dynamic neural activity during stress signals resilient coping

    OpenAIRE

    Sinha, Rajita; Lacadie, Cheryl M; Constable, R. Todd; Seo, Dongju

    2016-01-01

    We live in a time of increasing terror, stress, and trauma, and yet humans show a remarkable ability to cope under high stress states. How the brain supports such active resilient coping is not well-understood. Findings showed high stress levels are accompanied by dynamic brain signals in circuits representing the stress reaction, adaptation, and behavioral control responses. In addition, a ventromedial prefrontal cortical region showed initial decreases in brain activation, but then mobilize...

  15. Resveratrol sequentially induces replication and oxidative stresses to drive p53-CXCR2 mediated cellular senescence in cancer cells.

    Science.gov (United States)

    Li, Boxuan; Hou, Dong; Guo, Haiyang; Zhou, Haibin; Zhang, Shouji; Xu, Xiuhua; Liu, Qiao; Zhang, Xiyu; Zou, Yongxin; Gong, Yaoqin; Shao, Changshun

    2017-03-16

    Resveratrol (RSV) acts either as an antioxidant or a pro-oxidant depending on contexts. RSV-treated cancer cells may experience replication stress that can lead to cellular senescence or apoptosis. While both oxidative and replication stresses may mediate the anti-proliferation effect of RSV, to what extent each contributes to the impaired proliferation in response to RSV remains uncharacterized. We here report the study of the roles of replication and oxidative stresses in mediating cellular senescence in cancer cells treated with RSV. RSV induced S-phase arrest and cellular senescence in a dose-dependent manner in U2OS and A549 cancer cells as well as in normal human fibroblasts. We observed that nucleosides significantly alleviated RSV-induced replication stress and DNA damage response, and consequently attenuating cellular senescence. While the elevation of reactive oxygen species (ROS) also mediated the pro-senescent effect of RSV, it occurred after S-phase arrest. However, the induction of ROS by RSV was independent of S-phase arrest and actually reinforced the latter. We also demonstrated a critical role of the p53-CXCR2 axis in mediating RSV-induced senescence. Interestingly, CXCR2 also functioned as a barrier to apoptosis. Together, our results provided more insights into the biology of RSV-induced stress and its cellular consequences.

  16. New origin firing is inhibited by APC/CCdh1 activation in S-phase after severe replication stress.

    Science.gov (United States)

    Ercilla, Amaia; Llopis, Alba; Feu, Sonia; Aranda, Sergi; Ernfors, Patrik; Freire, Raimundo; Agell, Neus

    2016-06-01

    Defects in DNA replication and repair are known to promote genomic instability, a hallmark of cancer cells. Thus, eukaryotic cells have developed complex mechanisms to ensure accurate duplication of their genomes. While DNA damage response has been extensively studied in tumour cells, the pathways implicated in the response to replication stress are less well understood especially in non-transformed cells. Here we show that in non-transformed cells, APC/C(Cdh1) is activated upon severe replication stress. Activation of APC/C(Cdh1) prevents new origin firing and induces permanent arrest in S-phase. Moreover, Rad51-mediated homologous recombination is also impaired under these conditions. APC/C(Cdh1) activation in S-phase occurs after replication forks have been processed into double strand breaks. Remarkably, this activation, which correlates with decreased Emi1 levels, is not prevented by ATR/ATM inhibition, but it is abrogated in cells depleted of p53 or p21. Importantly, we found that the lack of APC/C(Cdh1) activity correlated with an increase in genomic instability. Taken together, our results define a new APC/C(Cdh1) function that prevents cell cycle resumption after prolonged replication stress by inhibiting origin firing, which may act as an additional mechanism in safeguarding genome integrity.

  17. ROS as key players in plant stress signalling.

    Science.gov (United States)

    Baxter, Aaron; Mittler, Ron; Suzuki, Nobuhiro

    2014-03-01

    Reactive oxygen species (ROS) play an integral role as signalling molecules in the regulation of numerous biological processes such as growth, development, and responses to biotic and/or abiotic stimuli in plants. To some extent, various functions of ROS signalling are attributed to differences in the regulatory mechanisms of respiratory burst oxidase homologues (RBOHs) that are involved in a multitude of different signal transduction pathways activated in assorted tissue and cell types under fluctuating environmental conditions. Recent findings revealed that stress responses in plants are mediated by a temporal-spatial coordination between ROS and other signals that rely on production of stress-specific chemicals, compounds, and hormones. In this review we will provide an update of recent findings related to the integration of ROS signals with an array of signalling pathways aimed at regulating different responses in plants. In particular, we will address signals that confer systemic acquired resistance (SAR) or systemic acquired acclimation (SAA) in plants.

  18. DNA replication checkpoint signaling depends on a Rad53-Dbf4 N-terminal interaction in Saccharomyces cerevisiae.

    Science.gov (United States)

    Chen, Ying-Chou; Kenworthy, Jessica; Gabrielse, Carrie; Hänni, Christine; Zegerman, Philip; Weinreich, Michael

    2013-06-01

    Dbf4-dependent kinase (DDK) and cyclin-dependent kinase (CDK) are essential to initiate DNA replication at individual origins. During replication stress, the S-phase checkpoint inhibits the DDK- and CDK-dependent activation of late replication origins. Rad53 kinase is a central effector of the replication checkpoint and both binds to and phosphorylates Dbf4 to prevent late-origin firing. The molecular basis for the Rad53-Dbf4 physical interaction is not clear but occurs through the Dbf4 N terminus. Here we found that both Rad53 FHA1 and FHA2 domains, which specifically recognize phospho-threonine (pT), interacted with Dbf4 through an N-terminal sequence and an adjacent BRCT domain. Purified Rad53 FHA1 domain (but not FHA2) bound to a pT Dbf4 peptide in vitro, suggesting a possible phospho-threonine-dependent interaction between FHA1 and Dbf4. The Dbf4-Rad53 interaction is governed by multiple contacts that are separable from the Cdc5- and Msa1-binding sites in the Dbf4 N terminus. Importantly, abrogation of the Rad53-Dbf4 physical interaction blocked Dbf4 phosphorylation and allowed late-origin firing during replication checkpoint activation. This indicated that Rad53 must stably bind to Dbf4 to regulate its activity.

  19. The profile of lysosomal exoglycosidases in replicative and stress-induced senescence in early passage human fibroblasts

    Directory of Open Access Journals (Sweden)

    Małgorzata Knaś

    2012-07-01

    Full Text Available The aim of the present study was to assess the profiles of the exoglycosidases: N-acetyl-β-hexosoaminidase, β glucuronidase and β galactosidase, α mannosidase and α fucosidase in fibroblast culture undergoing replicative and stress-induced senescence. Half of the cell culture was grown in normal conditions, without the stressor, and the other half of the cell was treated with 0.15 mM tert-butylhydroperoxide. The activities of total N-acetyl-β-hexosoaminidase as well as β glucuronidase in the cell lysate were determined in duplicates using the method of Marciniak et al. The activities of β galactosidase, α mannosidase and α fucosidase in the cell lysate were determined in duplicates using the method of Chatteriee et al. with the modification by Zwierz et al. The activities of the exoglycosidases examined, with the exception of β glucuronidase, showed a significant increase between individual days of the experiment in both non-stressed and stressed fibroblast cell culture. On each day of the experiment, in the cell lysate of stressed fibroblasts, the activities of exoglycosidases were significantly higher compared to the non-stressed cells. There were very strong correlations between SA-β-GAL staining and b galactosidase activity on individual days of the experiment in both non-stressed and stressed fibroblast cell culture. Replicative and stress-induced senescence results in significant changes to the level of lysosomal exoglycosidases, and results in enhanced lysosomal degradative capacity.

  20. Involvement of Differential Relationship between HCV Replication and Hepatic PRR Signaling Gene Expression in Responsiveness to IFN-Based Therapy.

    Science.gov (United States)

    Yuki, Nobukazu; Matsumoto, Shinji; Kato, Michio; Yamaguchi, Toshikazu

    2013-01-01

    Aim. To gain an insight into the effect of HCV replication-associated interference with the IFN system on hepatic mRNA expression involved in IFN production. Methods. Relative mRNA expression of TLR3/RIG-I signaling genes involved in IFN- β production was correlated with positive- and negative-strand HCV RNAs in pretreatment liver tissues responsive and nonresponsive to peginterferon and ribavirin for chronic hepatitis C genotype 1. Treatment response was analyzed for per protocol population at weeks 12 (n = 45) and 24 (n = 40) and at 24 weeks aftertreatment (n = 38). Results. HCV replication had no relation to the expression of TLR3, RIG-I, TRIF, IPS-1, IRF3, and IFN- β mRNAs in responders. In striking contrast, positive- and/or negative-strand HCV showed positive correlations with TLR3, RIG-I, TRIF, IPS-1, and IRF3 mRNAs in week-12 nonresponders; with RIG-I, TRIF, IPS-1, and IRF3 mRNAs in week-24 nonresponders; and with TLR3, RIG-I, and IRF3 mRNAs in posttreatment nonresponders. Thus mRNA expression of TLR3/RIG-I signaling genes was increased in relation to viral replication in nonresponders. Conclusions. The findings in IFN nonresponders may imply a host feedback response to severe impairment of the IFN system associated with HCV replication.

  1. Targeting the replisome with transduced monoclonal antibodies triggers lethal DNA replication stress in cancer cells.

    Science.gov (United States)

    Desplancq, Dominique; Freund, Guillaume; Conic, Sascha; Sibler, Annie-Paule; Didier, Pascal; Stoessel, Audrey; Oulad-Abdelghani, Mustapha; Vigneron, Marc; Wagner, Jérôme; Mély, Yves; Chatton, Bruno; Tora, Laszlo; Weiss, Etienne

    2016-03-15

    Although chemical inhibition of the DNA damage response (DDR) in cancer cells triggers cell death, it is not clear if the fork blockade achieved with inhibitors that neutralise proteins of the replisome is sufficient on its own to overcome the DDR. Monoclonal antibodies to PCNA, which block the DNA elongation process in vitro, have been developed. When these antibodies were transduced into cancer cells, they are able to inhibit the incorporation of nucleoside analogues. When co-delivered with anti-PCNA siRNA, the cells were flattened and the size of their nuclei increased by up to 3-fold, prior to cell death. Analysis of these nuclei by super-resolution microscopy revealed the presence of large numbers of phosphorylated histone H2AX foci. A senescence-like phenotype of the transduced cells was also observed upon delivery of the corresponding Fab molecules or following PCNA gene disruption or when the Fab fragment of an antibody that neutralises DNA polymerase alpha was used. Primary melanoma cells and leukaemia cells that are resistant to chemical inhibitors were similarly affected by these antibody treatments. These results demonstrate that transduced antibodies can trigger a lethal DNA replication stress, which kills cancer cells by abolishing the biological activity of several constituents of the replisome.

  2. Jnk2 effects on tumor development, genetic instability and replicative stress in an oncogene-driven mouse mammary tumor model.

    Directory of Open Access Journals (Sweden)

    Peila Chen

    Full Text Available Oncogenes induce cell proliferation leading to replicative stress, DNA damage and genomic instability. A wide variety of cellular stresses activate c-Jun N-terminal kinase (JNK proteins, but few studies have directly addressed the roles of JNK isoforms in tumor development. Herein, we show that jnk2 knockout mice expressing the Polyoma Middle T Antigen transgene developed mammary tumors earlier and experienced higher tumor multiplicity compared to jnk2 wildtype mice. Lack of jnk2 expression was associated with higher tumor aneuploidy and reduced DNA damage response, as marked by fewer pH2AX and 53BP1 nuclear foci. Comparative genomic hybridization further confirmed increased genomic instability in PyV MT/jnk2-/- tumors. In vitro, PyV MT/jnk2-/- cells underwent replicative stress and cell death as evidenced by lower BrdU incorporation, and sustained chromatin licensing and DNA replication factor 1 (CDT1 and p21(Waf1 protein expression, and phosphorylation of Chk1 after serum stimulation, but this response was not associated with phosphorylation of p53 Ser15. Adenoviral overexpression of CDT1 led to similar differences between jnk2 wildtype and knockout cells. In normal mammary cells undergoing UV induced single stranded DNA breaks, JNK2 localized to RPA (Replication Protein A coated strands indicating that JNK2 responds early to single stranded DNA damage and is critical for subsequent recruitment of DNA repair proteins. Together, these data support that JNK2 prevents replicative stress by coordinating cell cycle progression and DNA damage repair mechanisms.

  3. Measuring stress variation with depth using Barkhausen signals

    Science.gov (United States)

    Kypris, O.; Nlebedim, I. C.; Jiles, D. C.

    2016-06-01

    Magnetic Barkhausen noise analysis (BNA) is an established technique for the characterization of stress in ferromagnetic materials. An important application is the evaluation of residual stress in aerospace components, where shot-peening is used to strengthen the part by inducing compressive residual stresses on its surface. However, the evaluation of the resulting stress-depth gradients cannot be achieved by conventional BNA methods, where signals are interpreted in the time domain. The immediate alternative of using x-ray diffraction stress analysis is less than ideal, as the use of electropolishing to remove surface layers renders the part useless after inspection. Thus, a need for advancing the current BNA techniques prevails. In this work, it is shown how a parametric model for the frequency spectrum of Barkhausen emissions can be used to detect variations of stress along depth in ferromagnetic materials. Proof of concept is demonstrated by inducing linear stress-depth gradients using four-point bending, and fitting the model to the frequency spectra of measured Barkhausen signals, using a simulated annealing algorithm to extract the model parameters. Validation of our model suggests that in bulk samples the Barkhausen frequency spectrum can be expressed by a multi-exponential function with a dependence on stress and depth. One practical application of this spectroscopy method is the non-destructive evaluation of residual stress-depth profiles in aerospace components, thus helping to prevent catastrophic failures.

  4. PCNA-Dependent Cleavage and Degradation of SDE2 Regulates Response to Replication Stress

    OpenAIRE

    Jo, Ukhyun; Cai, Winson; Wang, Jingming; Kwon,Yoojin; D’Andrea, Alan D.; Kim, Hyungjin

    2016-01-01

    Maintaining genomic integrity during DNA replication is essential for cellular survival and for preventing tumorigenesis. Proliferating cell nuclear antigen (PCNA) functions as a processivity factor for DNA replication, and posttranslational modification of PCNA plays a key role in coordinating DNA repair against replication-blocking lesions by providing a platform to recruit factors required for DNA repair and cell cycle control. Here, we identify human SDE2 as a new genome surveillance fact...

  5. Brucella suis Vaccine Strain 2 Induces Endoplasmic Reticulum Stress that Affects Intracellular Replication in Goat Trophoblast Cells In vitro.

    Science.gov (United States)

    Wang, Xiangguo; Lin, Pengfei; Li, Yang; Xiang, Caixia; Yin, Yanlong; Chen, Zhi; Du, Yue; Zhou, Dong; Jin, Yaping; Wang, Aihua

    2016-01-01

    Brucella has been reported to impair placental trophoblasts, a cellular target where Brucella efficiently replicates in association with the endoplasmic reticulum (ER), and ultimately trigger abortion in pregnant animals. However, the precise effects of Brucella on trophoblast cells remain unclear. Here, we describe the infection and replication of Brucella suis vaccine strain 2 (B.suis.S2) in goat trophoblast cells (GTCs) and the cellular and molecular responses induced in vitro. Our studies demonstrated that B.suis.S2 was able to infect and proliferate to high titers, hamper the proliferation of GTCs and induce apoptosis due to ER stress. Tunicamycin (Tm), a pharmacological chaperone that strongly mounts ER stress-induced apoptosis, inhibited B.suis.S2 replication in GTCs. In addition, 4 phenyl butyric acid (4-PBA), a pharmacological chaperone that alleviates ER stress-induced apoptosis, significantly enhanced B.suis.S2 replication in GTCs. The Unfolded Protein Response (UPR) chaperone molecule GRP78 also promoted B.suis.S2 proliferation in GTCs by inhibiting ER stress-induced apoptosis. We also discovered that the IRE1 pathway, but not the PERK or ATF6 pathway, was activated in the process. However, decreasing the expression of phosphoIRE1α and IRE1α proteins with Irestatin 9389 (IRE1 antagonist) in GTCs did not affect the proliferation of B.suis.S2. Although GTC implantation was not affected upon B.suis.S2 infection, progesterone secretion was suppressed, and prolactin and estrogen secretion increased; these effects were accompanied by changes in the expression of genes encoding key steroidogenic enzymes. This study systematically explored the mechanisms of abortion in Brucella infection from the viewpoint of pathogen invasion, ER stress and reproductive endocrinology. Our findings may provide new insight for understanding the mechanisms involved in goat abortions caused by Brucella infection.

  6. Brucella suis vaccine strain 2 induces endoplasmic reticulum stress that affects intracellular replication in goat trophoblast cells in vitro

    Directory of Open Access Journals (Sweden)

    Xiangguo eWang

    2016-02-01

    Full Text Available Brucella has been reported to impair placental trophoblasts, a cellular target where Brucella efficiently replicates in association with the endoplasmic reticulum (ER, and ultimately trigger abortion in pregnant animals. However, the precise effects of Brucella on trophoblast cells remain unclear. Here, we describe the infection and replication of Brucella suis vaccine strain 2 (B.suis.S2 in goat trophoblast cells (GTCs and the cellular and molecular responses induced in vitro. Our studies demonstrated that B.suis.S2 was able to infect and proliferate to high titers, hamper the proliferation of GTCs and induce apoptosis due to ER stress. Tunicamycin (Tm, a pharmacological chaperone that strongly mounts ER stress-induced apoptosis, inhibited B.suis.S2 replication in GTCs. In addition, 4 phenyl butyric acid (4-PBA, a pharmacological chaperone that alleviates ER stress-induced apoptosis, significantly enhanced B.suis.S2 replication in GTCs. The Unfolded Protein Response (UPR chaperone molecule GRP78 also promoted B.suis.S2 proliferation in GTCs by inhibiting ER stress-induced apoptosis. We also discovered that the IRE1 pathway, but not the PERK or ATF6 pathway, was activated in the process. However, decreasing the expression of phosphoIRE1α and IRE1α proteins with Irestatin 9389 (IRE1 antagonist in GTCs did not affect the proliferation of B.suis.S2. Although GTC implantation was not affected upon B.suis.S2 infection, progesterone secretion was suppressed, and prolactin and estrogen secretion increased; these effects were accompanied by changes in the expression of genes encoding key steroidogenic enzymes. This study systematically explored the mechanisms of abortion in Brucella infection from the viewpoint of pathogen invasion, ER stress and reproductive endocrinology. Our findings may provide new insight for understanding the mechanisms involved in goat abortions caused by Brucella infection.

  7. Telomerase is essential to alleviate pif1-induced replication stress at telomeres

    NARCIS (Netherlands)

    Chang, Michael; Luke, Brian; Kraft, Claudine; Li, Zhijian; Peter, Matthias; Lingner, Joachim; Rothstein, Rodney

    2009-01-01

    Pif1, an evolutionarily conserved helicase, negatively regulates telomere length by removing telomerase from chromosome ends. Pif1 has also been implicated in DNA replication processes such as Okazaki fragment maturation and replication fork pausing. We find that overexpression of Saccharomyces cerv

  8. Endocannabinoid signalling modulates susceptibility to traumatic stress exposure

    Science.gov (United States)

    Bluett, Rebecca J.; Báldi, Rita; Haymer, Andre; Gaulden, Andrew D.; Hartley, Nolan D.; Parrish, Walker P.; Baechle, Jordan; Marcus, David J.; Mardam-Bey, Ramzi; Shonesy, Brian C.; Uddin, Md. Jashim; Marnett, Lawrence J.; Mackie, Ken; Colbran, Roger J.; Winder, Danny G.; Patel, Sachin

    2017-01-01

    Stress is a ubiquitous risk factor for the exacerbation and development of affective disorders including major depression and posttraumatic stress disorder. Understanding the neurobiological mechanisms conferring resilience to the adverse consequences of stress could have broad implications for the treatment and prevention of mood and anxiety disorders. We utilize laboratory mice and their innate inter-individual differences in stress-susceptibility to demonstrate a critical role for the endogenous cannabinoid 2-arachidonoylglycerol (2-AG) in stress-resilience. Specifically, systemic 2-AG augmentation is associated with a stress-resilient phenotype and enhances resilience in previously susceptible mice, while systemic 2-AG depletion or CB1 receptor blockade increases susceptibility in previously resilient mice. Moreover, stress-resilience is associated with increased phasic 2-AG-mediated synaptic suppression at ventral hippocampal-amygdala glutamatergic synapses and amygdala-specific 2-AG depletion impairs successful adaptation to repeated stress. These data indicate amygdala 2-AG signalling mechanisms promote resilience to adverse effects of acute traumatic stress and facilitate adaptation to repeated stress exposure. PMID:28348378

  9. Are Luxury Brand Labels and “Green” Labels Costly Signals of Social Status? An Extended Replication

    Science.gov (United States)

    2017-01-01

    Costly signaling theory provides an explanation for why humans are willing to a pay a premium for conspicuous products such as luxury brand-labeled clothing or conspicuous environmentally friendly cars. According to the theory, the extra cost of such products is a signal of social status and wealth and leads to advantages in social interactions for the signaler. A previous study found positive evidence for the case of luxury brand labels. However, an issue of this study was that some of the experiments were not conducted in a perfectly double-blind manner. I resolved this by replicating variations of the original design in a double-blind procedure. Additionally, besides the luxury label condition, I introduced a “green” label condition. Thus, the hypothesis that signaling theory is able to explain pro-environmental behavior was tested for the first time in a natural field setting. Further, I conducted experiments in both average and below-average socioeconomic neighborhoods, where, according to signaling theory, the effects of luxury signals should be even stronger. In contrast to the original study, I did not find positive effects of the luxury brand label in any of the five experiments. Nor did I find evidence for a green-signaling effect. Moreover, in poor neighborhoods a negative tendency of the luxury label actually became evident. This suggests that a signaling theory explanation of costly labels must take into account the characteristics of the observers, e.g. their social status. PMID:28170399

  10. Signaling Pathways and Molecular Mechanisms of Oxidative Stress in Skeletal Muscle

    Institute of Scientific and Technical Information of China (English)

    Haibing HU; Wenjing LI; Zhi FANG; Bo XUE; Longzhou LIU; Ye YANG

    2015-01-01

    Oxidative stress is a major factor affecting animal health and production performance. This paper briefly introduced the signaling pathways(i.e. NF-κB signal-ing pathway, MAPK, AP-1 and PGC-1α) of oxidative stress and the main genes regulating the signals of oxidative stress in skeletal muscle, providing a theoretical basis for reducing oxidative stress damage.

  11. Predicting financial stress events: A signal extraction approach

    OpenAIRE

    Christensen, Ian; Li, Fuchun

    2014-01-01

    The objective of this paper is to propose an early warning system that can predict the likelihood of the occurrence of financial stress events within a given period of time. To achieve this goal, the signal extraction approach proposed by Kaminsky, Lizondo and Reinhart (1998) is used to monitor the evolution of a number of economic indicators that tend to exhibit an unusual behaviour in the periods preceding a financial stress event. Based on the individual indicators, we propose three differ...

  12. Attenuation of replication stress-induced premature cellular senescence to assess anti-aging modalities.

    Science.gov (United States)

    Zhao, Hong; Darzynkiewicz, Zbigniew

    2014-01-01

    Described is an in vitro model of premature senescence in pulmonary adenocarcinoma A549 cells induced by persistent DNA replication stress in response to treatment with the DNA damaging drug mitoxantrone (Mxt). The degree of cellular senescence, based on characteristic changes in cell morphology, is measured by laser scanning cytometry. Specifically, the flattening of cells grown on slides (considered the hallmark of cellular senescence) is measured as the decline in local intensity of DNA-associated DAPI fluorescence (represented by maximal pixels). This change is paralleled by an increase in nuclear area. Thus, the ratio of mean intensity of maximal pixels to nuclear area provides a very sensitive morphometric biomarker for the degree of senescence. This analysis is combined with immunocytochemical detection of senescence markers, such as overexpression of cyclin kinase inhibitors (e.g., p21(WAF1) ) and phosphorylation of ribosomal protein S6 (rpS6), a key marker associated with aging/senescence that is detected using a phospho-specific antibody. These biomarker indices are presented in quantitative terms defined as a senescence index (SI), which is the fraction of the marker in test cultures relative to the same marker in exponentially growing control cultures. This system can be used to evaluate the anti-aging potential of test agents by assessing attenuation of maximal senescence. As an example, the inclusion of berberine, a natural alkaloid with reported anti-aging properties and a long history of use in traditional Chinese medicine, is shown to markedly attenuate the Mxt-induced SI and phosphorylation of rpS6. The multivariate analysis of senescence markers by laser scanning cytometry offers a promising tool to explore the potential anti-aging properties of a variety agents.

  13. Signalling crosstalk in light stress and immune reactions in plants.

    Science.gov (United States)

    Trotta, Andrea; Rahikainen, Moona; Konert, Grzegorz; Finazzi, Giovanni; Kangasjärvi, Saijaliisa

    2014-04-19

    The evolutionary history of plants is tightly connected with the evolution of microbial pathogens and herbivores, which use photosynthetic end products as a source of life. In these interactions, plants, as the stationary party, have evolved sophisticated mechanisms to sense, signal and respond to the presence of external stress agents. Chloroplasts are metabolically versatile organelles that carry out fundamental functions in determining appropriate immune reactions in plants. Besides photosynthesis, chloroplasts host key steps in the biosynthesis of amino acids, stress hormones and secondary metabolites, which have a great impact on resistance against pathogens and insect herbivores. Changes in chloroplast redox signalling pathways and reactive oxygen species metabolism also mediate local and systemic signals, which modulate plant resistance to light stress and disease. Moreover, interplay among chloroplastic signalling networks and plasma membrane receptor kinases is emerging as a key mechanism that modulates stress responses in plants. This review highlights the central role of chloroplasts in the signalling crosstalk that essentially determines the outcome of plant-pathogen interactions in plants.

  14. Proteomic Analysis of Rice Leaves Shows the Different Regulations to Osmotic Stress and Stress Signals

    Institute of Scientific and Technical Information of China (English)

    Lie-Bo Shu; Wei Ding; Jin-Hong Wu; Fang-Jun Feng; Li-Jun Luo; Han-Wei Mei

    2010-01-01

    Following the idea of partial root-zone drying(PRD)in crop cultivation,the morphological and physiological responses to partial root osmotic stress(PROS)and whole root osmotic stress(WROS)were investigated in rice.WROS caused stress symptoms like leaf rolling and membrane leakage.PROS stimulated stress signals,but did not cause severe leaf damage.By proteomic analysis,a total of 58 proteins showed differential expression after one or both treatments,and functional classification of these proteins suggests that stress signals regulate photosynthesis,carbohydrate and energy metabolism.Two other proteins(anthranilate synthase and submergence-induced nickel-binding protein)were upregulated only in the PROS plants,indicating their important roles in stress resistance.Additionally,more enzymes were involved in stress defense,redox homeostasis,lignin and ethylene synthesis in WROS leaves,suggesting a more comprehensive regulatory mechanism induced by osmotic stress.This study provides new insights into the complex molecular networks within plant leaves involved in the adaptation to osmotic stress and stress signals.

  15. Physiological Stress Mediates the Honesty of Social Signals

    OpenAIRE

    2009-01-01

    BACKGROUND: Extravagant ornaments used as social signals evolved to advertise their bearers' quality. The Immunocompetence Handicap Hypothesis proposes that testosterone-dependent ornaments reliably signal health and parasite resistance; however, empirical studies have shown mixed support. Alternatively, immune function and parasite resistance may be indirectly or directly related to glucocorticoid stress hormones. We propose that an understanding of the interplay between the individual and i...

  16. Biochemical mechanisms of signaling: perspectives in plants under arsenic stress.

    Science.gov (United States)

    Islam, Ejazul; Khan, Muhammad Tahir; Irem, Samra

    2015-04-01

    Plants are the ultimate food source for humans, either directly or indirectly. Being sessile in nature, they are exposed to various biotic and abiotic stresses because of changing climate that adversely effects their growth and development. Contamination of heavy metals is one of the major abiotic stresses because of anthropogenic as well as natural factors which lead to increased toxicity and accumulation in plants. Arsenic is a naturally occurring metalloid toxin present in the earth crust. Due to its presence in terrestrial and aquatic environments, it effects the growth of plants. Plants can tolerate arsenic using several mechanisms like phytochelation, vacuole sequestration and activation of antioxidant defense systems. Several signaling mechanisms have evolved in plants that involve the use of proteins, calcium ions, hormones, reactive oxygen species and nitric oxide as signaling molecules to cope with arsenic toxicity. These mechanisms facilitate plants to survive under metal stress by activating their defense systems. The pathways by which these stress signals are perceived and responded is an unexplored area of research and there are lots of gaps still to be filled. A good understanding of these signaling pathways can help in raising the plants which can perform better in arsenic contaminated soil and water. In order to increase the survival of plants in contaminated areas there is a strong need to identify suitable gene targets that can be modified according to needs of the stakeholders using various biotechnological techniques. This review focuses on the signaling mechanisms of plants grown under arsenic stress and will give an insight of the different sensory systems in plants. Furthermore, it provides the knowledge about several pathways that can be exploited to develop plant cultivars which are resistant to arsenic stress or can reduce its uptake to minimize the risk of arsenic toxicity through food chain thus ensuring food security.

  17. Bridges between mitochondrial oxidative stress, ER stress and mTOR signaling in pancreatic β cells.

    Science.gov (United States)

    Wang, Jing; Yang, Xin; Zhang, Jingjing

    2016-08-01

    Pancreatic β cell dysfunction, i.e., failure to provide insulin in concentrations sufficient to control blood sugar, is central to the etiology of all types of diabetes. Current evidence implicates mitochondrial oxidative stress and endoplasmic reticulum (ER) stress in pancreatic β cell loss and impaired insulin secretion. Oxidative and ER stress are interconnected so that misfolded proteins induce reactive oxygen species (ROS) production; likewise, oxidative stress disturbs the ER redox state thereby disrupting correct disulfide bond formation and proper protein folding. mTOR signaling regulates many metabolic processes including protein synthesis, cell growth, survival and proliferation. Oxidative stress inhibits mTORC1, which is considered an important suppressor of mitochondrial oxidative stress in β cells, and ultimately, controls cell survival. The interplay between ER stress and mTORC1 is complicated, since the unfolded protein response (UPR) activation can occur upstream or downstream of mTORC1. Persistent activation of mTORC1 initiates protein synthesis and UPR activation, while in the later phase induces ER stress. Chronic activation of ER stress inhibits Akt/mTORC1 pathway, while under particular settings, acute activation of UPR activates Akt-mTOR signaling. Thus, modulating mitochondrial oxidative stress and ER stress via mTOR signaling may be an approach that will effectively suppress obesity- or glucolipotoxicity-induced metabolic disorders such as insulin resistance and type 2 diabetes mellitus (T2DM). In this review, we focus on the regulations between mTOR signaling and mitochondrial oxidative or ER stress in pancreatic β cells.

  18. Adapting the Stress Response: Viral Subversion of the mTOR Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Valerie Le Sage

    2016-05-01

    Full Text Available The mammalian target of rapamycin (mTOR is a central regulator of gene expression, translation and various metabolic processes. Multiple extracellular (growth factors and intracellular (energy status molecular signals as well as a variety of stressors are integrated into the mTOR pathway. Viral infection is a significant stress that can activate, reduce or even suppress the mTOR signaling pathway. Consequently, viruses have evolved a plethora of different mechanisms to attack and co-opt the mTOR pathway in order to make the host cell a hospitable environment for replication. A more comprehensive knowledge of different viral interactions may provide fruitful targets for new antiviral drugs.

  19. Dynamic neural activity during stress signals resilient coping.

    Science.gov (United States)

    Sinha, Rajita; Lacadie, Cheryl M; Constable, R Todd; Seo, Dongju

    2016-08-02

    Active coping underlies a healthy stress response, but neural processes supporting such resilient coping are not well-known. Using a brief, sustained exposure paradigm contrasting highly stressful, threatening, and violent stimuli versus nonaversive neutral visual stimuli in a functional magnetic resonance imaging (fMRI) study, we show significant subjective, physiologic, and endocrine increases and temporally related dynamically distinct patterns of neural activation in brain circuits underlying the stress response. First, stress-specific sustained increases in the amygdala, striatum, hypothalamus, midbrain, right insula, and right dorsolateral prefrontal cortex (DLPFC) regions supported the stress processing and reactivity circuit. Second, dynamic neural activation during stress versus neutral runs, showing early increases followed by later reduced activation in the ventrolateral prefrontal cortex (VLPFC), dorsal anterior cingulate cortex (dACC), left DLPFC, hippocampus, and left insula, suggested a stress adaptation response network. Finally, dynamic stress-specific mobilization of the ventromedial prefrontal cortex (VmPFC), marked by initial hypoactivity followed by increased VmPFC activation, pointed to the VmPFC as a key locus of the emotional and behavioral control network. Consistent with this finding, greater neural flexibility signals in the VmPFC during stress correlated with active coping ratings whereas lower dynamic activity in the VmPFC also predicted a higher level of maladaptive coping behaviors in real life, including binge alcohol intake, emotional eating, and frequency of arguments and fights. These findings demonstrate acute functional neuroplasticity during stress, with distinct and separable brain networks that underlie critical components of the stress response, and a specific role for VmPFC neuroflexibility in stress-resilient coping.

  20. Endocannabinoid signaling in the amygdala: anatomy, synaptic signaling, behavior, and adaptations to stress.

    Science.gov (United States)

    Ramikie, T S; Patel, S

    2012-03-01

    The molecular constituents of endocannabinoid (eCB) signaling are abundantly expressed within the mammalian amygdaloid complex, consistent with the robust role of eCB signaling in the modulation of emotional behavior, learning, and stress-response physiology. Here, we detail the anatomical distribution of eCB signaling machinery in the amygdala and the role of this system in the modulation of excitatory and inhibitory neuroplasticity in this region. We also summarize recent findings demonstrating dynamic alternations in eCB signaling that occur in response to stress exposure, as well as known behavioral consequences of eCB-mediated modulation of amygdala function. Finally, we discuss how integrating anatomical and physiological data regarding eCB signaling in the amygdala could help elucidate common functional motifs of this system in relation to broader forebrain function. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

  1. Regulation of epidermal growth factor receptor signaling during oxidative stress

    NARCIS (Netherlands)

    Wit, Renate de

    2001-01-01

    This thesis described the effects of exposure of cells to oxidative stress,induced by H 2 O 2 ,on the functioning of proteins involved in signal transduction pathways.In addition, H 2 O 2 was chosen as oxidant in order to produce cellular screening assays to measure antioxidant efficacy in preventin

  2. Phospholipid signaling responses in salt-stressed rice leaves

    NARCIS (Netherlands)

    Darwish, E.; Testerink, C.; Khalil, M.; El-Shihy, O.; Munnik, T.

    2009-01-01

    Salinity is one of the major environmental factors limiting growth and productivity of rice plants. In this study, the effect of salt stress on phospholipid signaling responses in rice leaves was investigated. Leaf cuts were radiolabeled with 32 P-orthophosphate and the lipids extracted and analyzed

  3. Speculation: Polyamines are important in abiotic stress signaling.

    Science.gov (United States)

    Pál, Magda; Szalai, Gabriella; Janda, Tibor

    2015-08-01

    The main role of polyamines was originally assumed to be as direct protective compounds important under stress conditions. Although in some cases a correlation was found between the endogenous polyamine content and stress tolerance, this relationship cannot be generalized. Polyamines should no longer be considered simply as protective molecules, but rather as compounds that are involved in a complex signaling system and have a key role in the regulation of stress tolerance. The major links in polyamine signaling may be H2O2 and NO, which are not only produced in the course of the polyamine metabolism, but also transmit signals that influence gene expression via an increase in the cytoplasmic Ca(2+) level. Polyamines can also influence Ca(2+) influx independently of the H2O2- and/or NO-mediated pathways. Furthermore, these pathways may converge. In addition, several protein kinases have been shown to be influenced at the transcriptional or post-translational level by polyamines. Individual polyamines can be converted into each other in the polyamine cycle. In addition, their metabolism is linked with other hormones or signaling molecules. However, as individual polyamines trigger different transcriptional responses, other mechanisms and the existence of polyamine-responsive elements and the corresponding transacting protein factors are also involved in polyamine-related signaling pathways.

  4. Redox-dependent induction of antioxidant defenses by phenolic diterpenes confers stress tolerance in normal human skin fibroblasts: Insights on replicative senescence.

    Science.gov (United States)

    Carvalho, Ana C; Gomes, Andreia C; Pereira-Wilson, Cristina; Lima, Cristovao F

    2015-06-01

    Mild stress-induced hormesis represents a promising strategy for targeting the age-related accumulation of molecular damage and, therefore, for preventing diseases and achieving healthy aging. Fruits, vegetables, and spices contain a wide variety of hormetic phytochemicals, which may explain the beneficial health effects associated with the consumption of these dietary components. In the present study, the induction of cellular antioxidant defenses by the phenolic diterpenes carnosic acid (CA) and carnosol (CS) were studied in normal human skin fibroblasts, and insights into the aging process at the cellular level investigated. We observed that CA and CS induced several cytoprotective enzymes and antioxidant defenses in human fibroblasts, whose induction was dependent on the cellular redox state for CS and associated with Nrf2 signaling for both compounds. The stress response elicited by preincubation with CS conferred a cytoprotective action against a following oxidant challenge with tert-butyl hydroperoxide, confirming its hormetic effect. Preincubation of normal fibroblasts with CS also protected against hydrogen peroxide-induced premature senescence. Furthermore, cultivation of middle passage normal human skin fibroblasts in the presence of CS ameliorated the physiological state of cells during replicative senescence. Our results support the view that mild stress-induced antioxidant defenses by CS can confer stress tolerance in normal cells and may have important implications in the promotion of healthy aging.

  5. Fucoidan from Fucus vesiculosus suppresses hepatitis B virus replication by enhancing extracellular signal-regulated Kinase activation.

    Science.gov (United States)

    Li, Huifang; Li, Junru; Tang, Yuan; Lin, Lin; Xie, Zhanglian; Zhou, Jia; Zhang, Liyun; Zhang, Xiaoyong; Zhao, Xiaoshan; Chen, Zhengliang; Zuo, Daming

    2017-09-16

    Hepatitis B virus (HBV) infection is a serious public health problem leading to cirrhosis and hepatocellular carcinoma. As the clinical utility of current therapies is limited, the development of new therapeutic approaches for the prevention and treatment of HBV infection is imperative. Fucoidan is a natural sulfated polysaccharide that extracted from different species of brown seaweed, which was reported to exhibit various bioactivities. However, it remains unclear whether fucoidan influences HBV replication or not. The HBV-infected mouse model was established by hydrodynamic injection of HBV replicative plasmid, and the mice were treated with saline or fucoidan respectively. Besides, we also tested the inhibitory effect of fucoidan against HBV infection in HBV-transfected cell lines. The result showed that fucoidan from Fucus vesiculosus decreased serum HBV DNA, HBsAg and HBeAg levels and hepatic HBcAg expression in HBV-infected mice. Moreover, fucoidan treatment also suppressed intracellular HBcAg expression and the secretion of the HBV DNA as well as HBsAg and HBeAg in HBV-expressing cells. Furthermore, we proved that the inhibitory activity by fucoidan was due to the activation of the extracellular signal-regulated kinase (ERK) pathway and the subsequent production of type I interferon. Using specific inhibitor of ERK pathway abrogated the fucoidan-mediated inhibition of HBV replication. This study highlights that fucoidan might be served as an alternative therapeutic approach for the treatment of HBV infection.

  6. Excess Polθ functions in response to replicative stress in homologous recombination-proficient cancer cells

    Science.gov (United States)

    de Rugy, T. Goullet; Bashkurov, M.; Datti, A.; Betous, R.; Guitton-Sert, L.; Cazaux, C.; Durocher, D.

    2016-01-01

    ABSTRACT DNA polymerase theta (Polθ) is a specialized A-family DNA polymerase that functions in processes such as translesion synthesis (TLS), DNA double-strand break repair and DNA replication timing. Overexpression of POLQ, the gene encoding Polθ, is a prognostic marker for an adverse outcome in a wide range of human cancers. While increased Polθ dosage was recently suggested to promote survival of homologous recombination (HR)-deficient cancer cells, it remains unclear whether POLQ overexpression could be also beneficial to HR-proficient cancer cells. By performing a short interfering (si)RNA screen in which genes encoding druggable proteins were knocked down in Polθ-overexpressing cells as a means to uncover genetic vulnerabilities associated with POLQ overexpression, we could not identify genes that were essential for viability in Polθ-overexpressing cells in normal growth conditions. We also showed that, upon external DNA replication stress, Polθ expression promotes cell survival and limits genetic instability. Finally, we report that POLQ expression correlates with the expression of a set of HR genes in breast, lung and colorectal cancers. Collectively, our data suggest that Polθ upregulation, besides its importance for survival of HR-deficient cancer cells, may be crucial also for HR-proficient cells to better tolerate DNA replication stress, as part of a global gene deregulation response, including HR genes. PMID:27612511

  7. Excess Polθ functions in response to replicative stress in homologous recombination-proficient cancer cells

    Directory of Open Access Journals (Sweden)

    T. Goullet de Rugy

    2016-10-01

    Full Text Available DNA polymerase theta (Polθ is a specialized A-family DNA polymerase that functions in processes such as translesion synthesis (TLS, DNA double-strand break repair and DNA replication timing. Overexpression of POLQ, the gene encoding Polθ, is a prognostic marker for an adverse outcome in a wide range of human cancers. While increased Polθ dosage was recently suggested to promote survival of homologous recombination (HR-deficient cancer cells, it remains unclear whether POLQ overexpression could be also beneficial to HR-proficient cancer cells. By performing a short interfering (siRNA screen in which genes encoding druggable proteins were knocked down in Polθ-overexpressing cells as a means to uncover genetic vulnerabilities associated with POLQ overexpression, we could not identify genes that were essential for viability in Polθ-overexpressing cells in normal growth conditions. We also showed that, upon external DNA replication stress, Polθ expression promotes cell survival and limits genetic instability. Finally, we report that POLQ expression correlates with the expression of a set of HR genes in breast, lung and colorectal cancers. Collectively, our data suggest that Polθ upregulation, besides its importance for survival of HR-deficient cancer cells, may be crucial also for HR-proficient cells to better tolerate DNA replication stress, as part of a global gene deregulation response, including HR genes.

  8. Tocotrienol-Rich Fraction Ameliorates Antioxidant Defense Mechanisms and Improves Replicative Senescence-Associated Oxidative Stress in Human Myoblasts

    Directory of Open Access Journals (Sweden)

    Shy Cian Khor

    2017-01-01

    Full Text Available During aging, oxidative stress affects the normal function of satellite cells, with consequent regeneration defects that lead to sarcopenia. This study aimed to evaluate tocotrienol-rich fraction (TRF modulation in reestablishing the oxidative status of myoblasts during replicative senescence and to compare the effects of TRF with other antioxidants (α-tocopherol (ATF and N-acetyl-cysteine (NAC. Primary human myoblasts were cultured to young, presenescent, and senescent phases. The cells were treated with antioxidants for 24 h, followed by the assessment of free radical generation, lipid peroxidation, antioxidant enzyme mRNA expression and activities, and the ratio of reduced to oxidized glutathione. Our data showed that replicative senescence increased reactive oxygen species (ROS generation and lipid peroxidation in myoblasts. Treatment with TRF significantly diminished ROS production and decreased lipid peroxidation in senescent myoblasts. Moreover, the gene expression of superoxide dismutase (SOD2, catalase (CAT, and glutathione peroxidase (GPX1 was modulated by TRF treatment, with increased activity of superoxide dismutase and catalase and reduced glutathione peroxidase in senescent myoblasts. In comparison to ATF and NAC, TRF was more efficient in heightening the antioxidant capacity and reducing free radical insults. These results suggested that TRF is able to ameliorate antioxidant defense mechanisms and improves replicative senescence-associated oxidative stress in myoblasts.

  9. The C-terminal domain of chikungunya virus nsP2 independently governs viral RNA replication, cytopathicity, and inhibition of interferon signaling.

    Science.gov (United States)

    Fros, Jelke J; van der Maten, Erika; Vlak, Just M; Pijlman, Gorben P

    2013-09-01

    Alphavirus nonstructural protein 2 (nsP2) has pivotal roles in viral RNA replication, host cell shutoff, and inhibition of antiviral responses. Mutations that individually rendered other alphaviruses noncytopathic were introduced into chikungunya virus nsP2. Results show that (i) nsP2 mutation P718S only in combination with KR649AA or adaptive mutation D711G allowed noncytopathic replicon RNA replication, (ii) prohibiting nsP2 nuclear localization abrogates inhibition of antiviral interferon-induced JAK-STAT signaling, and (iii) nsP2 independently affects RNA replication, cytopathicity, and JAK-STAT signaling.

  10. Silymarin Suppresses Cellular Inflammation By Inducing Reparative Stress Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Lovelace, Erica S.; Wagoner, Jessica; MacDonald, James; Bammler, Theo; Bruckner, Jacob; Brownell, Jessica; Beyer, Richard; Zink, Erika M.; Kim, Young-Mo; Kyle, Jennifer E.; Webb-Robertson, Bobbie-Jo M.; Waters, Katrina M.; Metz, Thomas O.; Farin, Federico; Oberlies, Nicholas H.; Polyak, Steve

    2015-08-28

    Silymarin (SM), a natural product, is touted as a liver protectant and preventer of both chronic inflammation and diseases. To define how SM elicits these effects at a systems level, we performed transcriptional profiling, metabolomics, and signaling studies in human liver and T cell lines. Multiple pathways associated with cellular stress and metabolism were modulated by SM treatment within 0.5 to four hours: activation of Activating Transcription Factor 4 (ATF-4) and adenosine monophosphate protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling, the latter being associated with induction of DNA-damage-inducible transcript 4 (DDIT4). Metabolomics analyses revealed suppression of glycolytic, TCA cycle, and amino acid metabolism by SM treatment. Antiinflammatory effects arose with prolonged (i.e. 24 hours) SM exposure, with suppression of multiple proinflammatory mRNAs and nuclear factor kappa B (NF-κB) and forkhead box O (FOXO) signaling. Studies with murine knock out cells revealed that SM inhibition of both mTOR and NF-κB was partially AMPK dependent, while SM inhibition of the mTOR pathway in part required DDIT4. Thus, SM activates stress and repair responses that culminate in an anti-inflammatory phenotype. Other natural products induced similar stress responses, which correlated with their ability to suppress inflammation. Therefore, natural products like SM may be useful as tools to define how metabolic, stress, and repair pathways regulate cellular inflammation.

  11. Stress response signaling and virulence: insights from entomopathogenic fungi.

    Science.gov (United States)

    Ortiz-Urquiza, Almudena; Keyhani, Nemat O

    2015-08-01

    The Ascomycete fungal insect pathogens, Beauveria and Metarhizium spp. have emerged as model systems with which to probe diverse aspects of fungal growth, stress response, and pathogenesis. Due to the availability of genomic resources and the development of robust methods for genetic manipulation, the last 5 years have witnessed a rapid increase in the molecular characterization of genes and their pathways involved in stress response and signal transduction in these fungi. These studies have been performed mainly via characterization of gene deletion/knockout mutants and have included the targeting of general proteins involved in stress response and/or virulence, e.g. catalases, superoxide dismutases, and osmolyte balance maintenance enzymes, membrane proteins and signaling pathways including GPI anchored proteins and G-protein coupled membrane receptors, MAPK pathways, e.g. (i) the pheromone/nutrient sensing, Fus3/Kss1, (ii) the cell wall integrity, Mpk1, and (iii) the high osmolarity, Hog1, the PKA/adenyl cyclase pathway, and various downstream transcription factors, e.g. Msn2, CreA and Pac1. Here, we will discuss current research that strongly suggests extensive underlying contributions of these biochemical and signaling pathways to both abiotic stress response and virulence.

  12. Calcium efflux systems in stress signalling and adaptation in plants

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    Jayakumar eBose

    2011-12-01

    Full Text Available Transient cytosolic calcium ([Ca2+]cyt elevation is an ubiquitous denominator of the signalling network when plants are exposed to literally every known abiotic and biotic stress. These stress-induced [Ca2+]cyt elevations vary in magnitude, frequency and shape, depending on the severity of the stress as well the type of stress experienced. This creates a unique stress-specific calcium signature that is then decoded by signal transduction networks. While most published papers have been focused predominantly on the role of Ca2+ influx mechanisms in shaping [Ca2+]cyt signatures, restoration of the basal [Ca2+]cyt levels is impossible without both cytosolic Ca2+ buffering and efficient Ca2+ efflux mechanisms removing excess Ca2+ from cytosol, to reload Ca2+ stores and to terminate Ca2+ signalling. This is the topic of the current review. The molecular identity of two major types of Ca2+ efflux systems, Ca2+-ATPase pumps and Ca2+/H+ exchangers, is described, and their regulatory modes are analysed in detail. The spatial and temporal organisation of calcium signalling networks is described, and the importance of existence of intracellular calcium microdomains is discussed. Experimental evidence for the role of Ca2+ efflux systems in plant responses to a range of abiotic and biotic factors is summarised. Contribution of Ca2+-ATPase pumps and Ca2+/H+ exchangers in shaping [Ca2+]cyt signatures is then modelled by using a four-component model (plasma- and endo- membrane-based Ca2+-permeable channels and efflux systems taking into account the cytosolic Ca2+ buffering. It is concluded that physiologically relevant variations in the activity of Ca2+-ATPase pumps and Ca2+/H+ exchangers are sufficient to fully describe all the reported experimental evidence and determine the shape of [Ca2+]cyt signatures in response to environmental stimuli, emphasising the crucial role these active efflux systems play in plant adaptive responses to environment.

  13. Stress Signal Network between Hypoxia and ER Stress in Chronic Kidney Disease

    Science.gov (United States)

    Maekawa, Hiroshi; Inagi, Reiko

    2017-01-01

    Chronic kidney disease (CKD) is characterized by an irreversible decrease in kidney function and induction of various metabolic dysfunctions. Accumulated findings reveal that chronic hypoxic stress and endoplasmic reticulum (ER) stress are involved in a range of pathogenic conditions, including the progression of CKD. Because of the presence of an arteriovenous oxygen shunt, the kidney is thought to be susceptible to hypoxia. Chronic kidney hypoxia is induced by a number of pathogenic conditions, including renal ischemia, reduced peritubular capillary, and tubulointerstitial fibrosis. The ER is an organelle which helps maintain the quality of proteins through the unfolded protein response (UPR) pathway, and ER dysfunction associated with maladaptive UPR activation is named ER stress. ER stress is reported to be related to some of the effects of pathogenesis in kidney, particularly in the podocyte slit diaphragm and tubulointerstitium. Furthermore, chronic hypoxia mediates ER stress in blood vessel endothelial cells and tubulointerstitium via several mechanisms, including oxidative stress, epigenetic alteration, lipid metabolism, and the AKT pathway. In summary, a growing consensus considers that these stresses interact via complicated stress signal networks, which leads to the exacerbation of CKD (Figure 1). This stress signal network might be a target for interventions aimed at ameliorating CKD.

  14. Phosphatidic acid, a versatile water-stress signal in roots

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    Fionn eMcLoughlin

    2013-12-01

    Full Text Available Adequate water supply is of utmost importance for growth and reproduction of plants. In order to cope with water deprivation, plants have to adapt their development and metabolism to ensure survival. To maximize water use efficiency, plants use a large array of signaling mediators such as hormones, protein kinases and phosphatases, Ca2+, reactive oxygen species and low abundant phospholipids that together form complex signaling cascades. Phosphatidic acid (PA is a signaling lipid that rapidly accumulates in response to a wide array of abiotic stress stimuli. PA formation provides the cell with spatial and transient information about the external environment by acting as a protein-docking site in cellular membranes. PA reportedly binds to a number of proteins that play a role during water limiting conditions, such as drought and salinity and has been shown to play an important role in maintaining root system architecture. Members of two osmotic stress-activated protein kinase families, sucrose non-fermenting 1-related protein kinase 2 (SnRK2 and mitogen activated protein kinases (MAPKs were recently shown bind PA and are also involved in the maintenance of root system architecture and salinity stress tolerance. In addition, PA regulates several proteins involved in abscisic acid (ABA-signaling. PA-dependent recruitment of glyceraldehyde-3-phosphate dehydrogenase (GAPDH under water limiting conditions indicates a role in regulating metabolic processes. Finally, a recent study also shows the PA recruits the clathrin heavy chain and a potassium channel subunit, hinting towards additional roles in cellular trafficking and potassium homeostasis. Taken together, the rapidly increasing number of proteins reported to interact with PA implies a broad role for this versatile signaling phospholipid in mediating salt and water stress responses.

  15. Oxidized Extracellular DNA as a Stress Signal in Human Cells

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    Aleksei V. Ermakov

    2013-01-01

    Full Text Available The term “cell-free DNA” (cfDNA was recently coined for DNA fragments from plasma/serum, while DNA present in in vitro cell culture media is known as extracellular DNA (ecDNA. Under oxidative stress conditions, the levels of oxidative modification of cellular DNA and the rate of cell death increase. Dying cells release their damaged DNA, thus, contributing oxidized DNA fragments to the pool of cfDNA/ecDNA. Oxidized cell-free DNA could serve as a stress signal that promotes irradiation-induced bystander effect. Evidence points to TLR9 as a possible candidate for oxidized DNA sensor. An exposure to oxidized ecDNA stimulates a synthesis of reactive oxygen species (ROS that evokes an adaptive response that includes transposition of the homologous loci within the nucleus, polymerization and the formation of the stress fibers of the actin, as well as activation of the ribosomal gene expression, and nuclear translocation of NF-E2 related factor-2 (NRF2 that, in turn, mediates induction of phase II detoxifying and antioxidant enzymes. In conclusion, the oxidized DNA is a stress signal released in response to oxidative stress in the cultured cells and, possibly, in the human body; in particular, it might contribute to systemic abscopal effects of localized irradiation treatments.

  16. Replication stress caused by low MCM expression limits fetal erythropoiesis and hematopoietic stem cell functionality

    DEFF Research Database (Denmark)

    Alvarez, Silvia; Díaz, Marcos; Flach, Johanna

    2015-01-01

    -chromosome maintenance (MCM)3 that limiting origin licensing in vivo affects the functionality of hematopoietic stem cells and the differentiation of rapidly-dividing erythrocyte precursors. Mcm3-deficient erythroblasts display aberrant DNA replication patterns and fail to complete maturation, causing lethal anemia. Our......' origins provide a backup in the presence of stalled forks and may confer flexibility to the replication program in specific cell types during differentiation, a role that has remained unexplored. Here we show, using a mouse strain with hypomorphic expression of the origin licensing factor mini...

  17. Signal Traits and Oxidative Stress: A Comparative Study Across Populations with Divergent Signals

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    Maren N Vitousek

    2016-05-01

    Full Text Available Diverging populations often shift patterns of signal use – a process that can contribute to reproductive isolation and speciation. Yet it is not clear why most traits gain or lose signal value during divergence. One reason this could occur is because changes in the relationship between signals and relevant physiological parameters degrade the reliability of a signal, or even change its underlying information content. Here we test the hypothesis that the relationship between signal trait elaboration and a central component of organismal health – oxidative stress – differs across closely related populations that have diverged in signal use and preferences. In the recently diverged barn swallow subspecies complex (Hirundo rustica, Family: Hirundinidae, different populations use different traits as sexual signals. Two of these traits, ventral breast plumage color and tail streamer length, differ markedly between North American H. r. erythrogaster and European H. r. rustica. Despite this divergence, variation in ventral plumage color was similarly associated with measures of oxidative damage across both populations. However, the directionality of these relationships differed between the sexes: darker male barn swallows had higher levels of plasma oxidative damage than their lighter counterparts, while the opposite relationship was seen in females. In contrast, relationships between tail streamer length and measures of oxidative stress were not consistent across populations. Some analyses indicated that in European H. r. rustica, where males bearing elongated streamers are preferred as mates, longer-streamered males were more oxidatively stressed; however, the opposite pattern was suggested in North American H. r. erythrogaster. Tail streamer length was not associated with measures of oxidative stress in females of either population. Differences in the physiological state of stronger signalers across populations and between the sexes may be

  18. Borna disease virus phosphoprotein modulates epigenetic signaling in neurons to control viral replication.

    Science.gov (United States)

    Bonnaud, Emilie M; Szelechowski, Marion; Bétourné, Alexandre; Foret, Charlotte; Thouard, Anne; Gonzalez-Dunia, Daniel; Malnou, Cécile E

    2015-06-01

    Understanding the modalities of interaction of neurotropic viruses with their target cells represents a major challenge that may improve our knowledge of many human neurological disorders for which viral origin is suspected. Borna disease virus (BDV) represents an ideal model to analyze the molecular mechanisms of viral persistence in neurons and its consequences for neuronal homeostasis. It is now established that BDV ensures its long-term maintenance in infected cells through a stable interaction of viral components with the host cell chromatin, in particular, with core histones. This has led to our hypothesis that such an interaction may trigger epigenetic changes in the host cell. Here, we focused on histone acetylation, which plays key roles in epigenetic regulation of gene expression, notably for neurons. We performed a comparative analysis of histone acetylation patterns of neurons infected or not infected by BDV, which revealed that infection decreases histone acetylation on selected lysine residues. We showed that the BDV phosphoprotein (P) is responsible for these perturbations, even when it is expressed alone independently of the viral context, and that this action depends on its phosphorylation by protein kinase C. We also demonstrated that BDV P inhibits cellular histone acetyltransferase activities. Finally, by pharmacologically manipulating cellular acetylation levels, we observed that inhibiting cellular acetyl transferases reduces viral replication in cell culture. Our findings reveal that manipulation of cellular epigenetics by BDV could be a means to modulate viral replication and thus illustrate a fascinating example of virus-host cell interaction. Persistent DNA viruses often subvert the mechanisms that regulate cellular chromatin dynamics, thereby benefitting from the resulting epigenetic changes to create a favorable milieu for their latent and persistent states. Here, we reasoned that Borna disease virus (BDV), the only RNA virus known to

  19. Effects of Cigarette Smoke Condensate on Oxidative Stress, Apoptotic Cell Death, and HIV Replication in Human Monocytic Cells.

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    Pss Rao

    Full Text Available While cigarette smoking is prevalent amongst HIV-infected patients, the effects of cigarette smoke constituents in cells of myeloid lineage are poorly known. Recently, we have shown that nicotine induces oxidative stress through cytochrome P450 (CYP 2A6-mediated pathway in U937 monocytic cells. The present study was designed to examine the effect of cigarette smoke condensate (CSC, which contains majority of tobacco constituents, on oxidative stress, cytotoxicity, expression of CYP1A1, and/or HIV-1 replication in HIV-infected (U1 and uninfected U937 cells. The effects of CSC on induction of CYP1 enzymes in HIV-infected primary macrophages were also analyzed. The results showed that the CSC-mediated increase in production of reactive oxygen species (ROS in U937 cells is dose- and time-dependent. Moreover, CSC treatment was found to induce cytotoxicity in U937 cells through the apoptotic pathway via activation of caspase-3. Importantly, pretreatment with vitamin C blocked the CSC-mediated production of ROS and induction of caspase-3 activity. In U1 cells, acute treatment of CSC increased ROS production at 6H (>2-fold and both ROS (>2 fold and HIV-1 replication (>3-fold after chronic treatment. The CSC mediated effects were associated with robust induction in the expression of CYP1A1 mRNA upon acute CSC treatment of U937 and U1 cells (>20-fold, and upon chronic CSC treatment to U1 cells (>30-fold. In addition, the CYP1A1 induction in U937 cells was mediated through the aromatic hydrocarbon receptor pathway. Lastly, CSC, which is known to increase viral replication in primary macrophages, was also found to induce CYP1 enzymes in HIV-infected primary macrophages. While mRNA levels of both CYP1A1 and CYP1B1 were elevated following CSC treatment, only CYP1B1 protein levels were increased in HIV-infected primary macrophages. In conclusion, these results suggest a possible association between oxidative stress, CYP1 expression, and viral replication in

  20. Endoplasmic Reticulum Stress Induced Synthesis of a Novel Viral Factor Mediates Efficient Replication of Genotype-1 Hepatitis E Virus.

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    Vidya P Nair

    2016-04-01

    Full Text Available Hepatitis E virus (HEV causes acute hepatitis in many parts of the world including Asia, Africa and Latin America. Though self-limiting in normal individuals, it results in ~30% mortality in infected pregnant women. It has also been reported to cause acute and chronic hepatitis in organ transplant patients. Of the seven viral genotypes, genotype-1 virus infects humans and is a major public health concern in South Asian countries. Sporadic cases of genotype-3 and 4 infection in human and animals such as pigs, deer, mongeese have been reported primarily from industrialized countries. Genotype-5, 6 and 7 viruses are known to infect animals such as wild boar and camel, respectively. Genotype-3 and 4 viruses have been successfully propagated in the laboratory in mammalian cell culture. However, genotype-1 virus replicates poorly in mammalian cell culture and no other efficient model exists to study its life cycle. Here, we report that endoplasmic reticulum (ER stress promotes genotype-1 HEV replication by inducing cap-independent, internal initiation mediated translation of a novel viral protein (named ORF4. Importantly, ORF4 expression and stimulatory effect of ER stress inducers on viral replication is specific to genotype-1. ORF4 protein sequence is mostly conserved among genotype-1 HEV isolates and ORF4 specific antibodies were detected in genotype-1 HEV patient serum. ORF4 interacted with multiple viral and host proteins and assembled a protein complex consisting of viral helicase, RNA dependent RNA polymerase (RdRp, X, host eEF1α1 (eukaryotic elongation factor 1 isoform-1 and tubulinβ. In association with eEF1α1, ORF4 stimulated viral RdRp activity. Furthermore, human hepatoma cells that stably express ORF4 or engineered proteasome resistant ORF4 mutant genome permitted enhanced viral replication. These findings reveal a positive role of ER stress in promoting genotype-1 HEV replication and pave the way towards development of an efficient

  1. AIP1-mediated stress signaling in atherosclerosis and arteriosclerosis.

    Science.gov (United States)

    Zhang, Jiqin; Zhou, Huanjiao Jenny; Ji, Weidong; Min, Wang

    2015-05-01

    AIP1 (ASK1-interacting protein-1; encoded by the DAB2IP gene), a signaling scaffolding protein, is abundantly expressed in vascular endothelial cells (EC). While it was initially discovered as an apoptosis signal-regulating kinase 1 (ASK1)-interacting protein, AIP1 broadly suppresses inflammatory responses triggered by cytokines and stresses such as TNF, LPS, VEGF, and endoplasmic reticulum (ER) stress in EC (therefore, AIP1 is an anti-inflammatory protein). Human genome-wide association study (GWAS) has identified DAB2IP gene variants conferring susceptibility to cardiovascular diseases. Consistently, a global or vascular EC-specific deletion of DAB2IP in mice strongly enhances inflammatory responses and exacerbates atherosclerosis and graft arteriosclerosis progression in mouse models. Mechanisms for AIP1 function and regulation associated with human cardiovascular diseases need further investigations.

  2. Electrical signaling in Aloe vera induced by localized thermal stress.

    Science.gov (United States)

    Volkov, Alexander G; Lang, Ryan D; Volkova-Gugeshashvili, Maia I

    2007-11-01

    Action potentials in higher plants are theorized as the information carriers in intercellular and intracellular communication in the presence of environmental stressors. Among the most common stressors is heat shock. Under stressful conditions, the response reactions of plant tissues and organs can be local or transmitted over long distances. In this article, the speeds of propagation of thermally induced action potentials in green plants are discussed, and their speeds were found to be comparable to those occurring in various mammalian species. These rapid action potentials in green plants were recorded in real time using modern data acquisition techniques. According to our measurements, a single application of localized heat stress induces fast action potentials in Aloe vera (67 m/s). Electrical signals propagated along all leaves of the A. vera plants were studied. Possible pathways for electrical signal propagation in vascular plants are also discussed.

  3. The yeast PUF protein Puf5 has Pop2-independent roles in response to DNA replication stress.

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    Ana Traven

    Full Text Available PUFs are RNA binding proteins that promote mRNA deadenylation and decay and inhibit translation. Yeast Puf5 is the prototype for studying PUF-dependent gene repression. Puf5 binds to the Pop2 subunit of the Ccr4-Pop2-NOT mRNA deadenylase, recruiting the deadenylase and associated translational repressors to mRNAs. Here we used yeast genetics to show that Puf5 has additional roles in vivo that do not require Pop2. Deletion of PUF5 caused increased sensitivity to DNA replication stress in cells lacking Pop2, as well as in cells mutated for two activities recruited to mRNAs by the Puf5-Pop2 interaction, the deadenylase Ccr4 and the translational repressor Dhh1. A functional Puf5 RNA binding domain was required, and Puf5 cytoplasmic localisation was sufficient for resistance to replication stress, indicating posttranscriptional gene expression control is involved. In contrast to DNA replication stress, in response to the cell wall integrity pathway activator caffeine, PUF5 and POP2 acted in the same genetic pathway, indicating that functions of Puf5 in the caffeine response are mediated by Pop2-dependent gene repression. Our results support a model in which Puf5 uses multiple, Pop2-dependent and Pop2-independent mechanisms to control mRNA expression. The Pop2-independent roles for Puf5 could involve spatial control of gene expression, a proposition supported by our data indicating that the active form of Puf5 is localised to cytoplasmic foci.

  4. Jasmonates and octadecanoids: signals in plant stress responses and development.

    Science.gov (United States)

    Wasternack, Claus; Hause, Bettrina

    2002-01-01

    Plants are sessile organisms. Consequently they have to adapt constantly to fluctuations in the environment. Some of these changes involve essential factors such as nutrients, light, and water. Plants have evolved independent systems to sense nutrients such as phosphate and nitrogen. However, many of the environmental factors may reach levels which represent stress for the plant. The fluctuations can range between moderate and unfavorable, and the factors can be of biotic or abiotic origin. Among the biotic factors influencing plant life are pathogens and herbivores. In case of bacteria and fungi, symbiotic interactions such as nitrogen-fixating nodules and mycorrhiza, respectively, may be established. In case of insects, a tritrophic interaction of herbivores, carnivores, and plants may occur mutualistically or parasitically. Among the numerous abiotic factors are low temperature, frost, heat, high light conditions, ultraviolet light, darkness, oxidation stress, hypoxia, wind, touch, nutrient imbalance, salt stress, osmotic adjustment, water deficit, and desiccation. In the last decade jasmonates were recognized as being signals in plant responses to most of these biotic and abiotic factors. Signaling via jasmonates was found to occur intracellularly, intercellularly, and systemically as well as interorganismically. Jasmonates are a group of ubiquitously occurring plant growth regulators originally found as the major constituents in the etheric oil of jasmine, and were first suggested to play a role in senescence due to a strong senescence-promoting effect. Subsequently, numerous developmental processes were described in which jasmonates exhibited hormone-like properties. Recent knowledge is reviewed here on jasmonates and their precursors, the octadecanoids. After discussing occurrence and biosynthesis, emphasis is placed upon the signal transduction pathways in plant stress responses in which jasmonates act as a signal. Finally, examples are described on the

  5. Human Adipose-Derived Stem Cells Expanded Under Ambient Oxygen Concentration Accumulate Oxidative DNA Lesions and Experience Procarcinogenic DNA Replication Stress.

    Science.gov (United States)

    Bétous, Rémy; Renoud, Marie-Laure; Hoede, Claire; Gonzalez, Ignacio; Jones, Natalie; Longy, Michel; Sensebé, Luc; Cazaux, Christophe; Hoffmann, Jean-Sébastien

    2017-01-01

    Adipose-derived stem cells (ADSCs) have led to growing interest in cell-based therapy because they can be easily harvested from an abundant tissue. ADSCs must be expanded in vitro before transplantation. This essential step causes concerns about the safety of adult stem cells in terms of potential transformation. Tumorigenesis is driven in its earliest step by DNA replication stress, which is characterized by the accumulation of stalled DNA replication forks and activation of the DNA damage response. Thus, to evaluate the safety of ADSCs during ex vivo expansion, we monitored DNA replication under atmospheric (21%) or physiologic (1%) oxygen concentration. Here, by combining immunofluorescence and DNA combing, we show that ADSCs cultured under 21% oxygen accumulate endogenous oxidative DNA lesions, which interfere with DNA replication by increasing fork stalling events, thereby leading to incomplete DNA replication and fork collapse. Moreover, we found by RNA sequencing (RNA-seq) that culture of ADSCs under atmospheric oxygen concentration leads to misexpression of cell cycle and DNA replication genes, which could contribute to DNA replication stress. Finally, analysis of acquired small nucleotide polymorphism shows that expansion of ADSCs under 21% oxygen induces a mutational bias toward deleterious transversions. Overall, our results suggest that expanding ADSCs at a low oxygen concentration could reduce the risk for DNA replication stress-associated transformation, as occurs in neoplastic tissues. Stem Cells Translational Medicine 2017;6:68-76.

  6. Hyperosmotic stress-induced apoptotic signaling pathways in chondrocytes.

    Science.gov (United States)

    Racz, Boglarka; Reglodi, Dora; Fodor, Barnabas; Gasz, Balazs; Lubics, Andrea; Gallyas, Ferenc; Roth, Erzsebet; Borsiczky, Balazs

    2007-06-01

    Articular chondrocytes have a well-developed osmoregulatory system that enables cells to survive in a constantly changing osmotic environment. However, osmotic loading exceeding that occurring under physiological conditions severely compromises chondrocyte function and leads to degenerative changes. The aim of the present study was to investigate the form of cell death and changes in apoptotic signaling pathways under hyperosmotic stress using a primary chondrocyte culture. Cell viability and apoptosis assays performed with annexin V and propidium iodide staining showed that a highly hyperosmotic medium (600 mOsm) severely reduced chondrocyte viability and led mainly to apoptotic cell death, while elevating osmotic pressure within the physiological range caused no changes compared to isosmotic conditions. Western blot analysis revealed that a 600 mOsm hyperosmotic environment induced the activation of proapoptotic members of the mitogen-activated protein kinase family such as c-Jun N-terminal kinase (JNK) and p38, and led to an increased level of extracellular signal regulated kinase (ERK1/2). Hyperosmotic stress also induced the activation of caspase-3. In summary, our results show that hyperosmotic stress leads to mainly apoptotic cell death via the involvement of proapoptotic signaling pathways in a primary chondrocyte culture.

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

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    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.

  8. The role of APC/C(Cdh1) in replication stress and origin of genomic instability.

    Science.gov (United States)

    Greil, C; Krohs, J; Schnerch, D; Follo, M; Felthaus, J; Engelhardt, M; Wäsch, R

    2016-06-01

    It has been proposed that the APC/C(Cdh1) functions as a tumor suppressor by maintaining genomic stability. However, the exact nature of genomic instability following loss of Cdh1 is unclear. Using biochemistry and live cell imaging of single cells we found that Cdh1 knockdown (kd) leads to strong nuclear stabilization of the substrates cyclin A and B and deregulated kinetics of DNA replication. Restoration of the Cdh1-dependent G2 DNA damage checkpoint did not result in G2 arrest but blocked cells in prometaphase, suggesting that these cells enter mitosis despite incomplete replication. This results in DNA double-strand breaks, anaphase bridges, cytokinesis defects and tetraploidization. Tetraploid cells are the source of supernumerary centrosomes following Cdh1-kd, leading to multipolar mitosis or centrosome clustering, in turn resulting in merotelic attachment and lagging chromosomes. Whereas some of these events cause apoptosis during mitosis, surviving cells may accumulate chromosomal aberrations.

  9. ATR-Chk1-APC/C-dependent stabilization of Cdc7-ASK (Dbf4) kinase is required for DNA lesion bypass under replication stress

    DEFF Research Database (Denmark)

    Yamada, M.; Watanabe, K.; Mistrik, M.

    2013-01-01

    Cdc7 kinase regulates DNA replication. However, its role in DNA repair and recombination is poorly understood. Here we describe a pathway that stabilizes the human Cdc7-ASK (activator of S-phase kinase; also called Dbf4), its regulation, and its function in cellular responses to compromised DNA...... replication. Stalled DNA replication evoked stabilization of the Cdc7-ASK (Dbf4) complex in a manner dependent on ATR-Chk1-mediated checkpoint signaling and its interplay with the anaphase-promoting complex/cyclosomeCdh1 (APC/C) ubiquitin ligase. Mechanistically, Chk1 kinase inactivates APC/C through......) with RAD18 disables foci formation by RAD18 and hinders chromatin loading of translesion DNA polymerase h. These findings define a novel mechanism that orchestrates replication checkpoint signaling and ubiquitin-proteasome machinery with the DNA damage bypass pathway to guard against replication collapse...

  10. Klotho Ameliorates Chemically Induced Endoplasmic Reticulum (ER Stress Signaling

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    Srijita Banerjee

    2013-05-01

    Full Text Available Background: Both endoplasmic reticulum (ER stress, a fundamental cell response associated with stress-initiated unfolded protein response (UPR, and loss of Klotho, an anti-aging hormone linked to NF-κB-induced inflammation, occur in chronic metabolic diseases such as obesity and type 2 diabetes. We investigated if the loss of Klotho is causally linked to increased ER stress. Methods: We treated human renal epithelial HK-2, alveolar epithelial A549, HEK293, and SH-SH-SY5Y neuroblastoma cells with ER stress-inducing agents, thapsigargin and/or tunicamycin. Effects of overexpression or siRNA-mediated knockdown of Klotho on UPR signaling was investigated by immunoblotting and Real-time PCR. Results: Elevated Klotho levels in HK-2 cells decreased expression of ER stress markers phospho-IRE1, XBP-1s, BiP, CHOP, pJNK, and phospho-p38, all of which were elevated in response to tunicamycin and/or thapsigargin. Similar results were observed using A549 cells for XBP-1s, BiP, and CHOP in response to thapsigargin. Conversely, knockdown of Klotho in HEK 293 cells using siRNA caused further thapsigargin-induced increases in pIRE-1, XBP-1s, and BiP. Klotho overexpression in A549 cells blocked thapsigargin-induced caspase and PARP cleavage and improved cell viability. Conclusion: Our data indicate that Klotho has an important role in regulating ER stress and that loss of Klotho is causally linked to ER stress-induced apoptosis.

  11. Activated Ras signaling pathways and reovirus oncolysis: an update on the mechanism of preferential reovirus replication in cancer cells

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    Jun eGong

    2014-06-01

    Full Text Available The development of wild-type, unmodified Type 3 Dearing (T3D strain reovirus as an anticancer agent has currently expanded to 32 clinical trials (both completed and ongoing involving reovirus in the treatment of cancer. It has been more than 30 years since the potential of reovirus as an anticancer agent was first identified in studies that demonstrated the preferential replication of reovirus in transformed cell lines but not in normal cells. Later investigations have revealed the involvement of activated Ras signaling pathways (both upstream and downstream and key steps of the reovirus infectious cycle in promoting preferential replication in cancer cells with reovirus-induced cancer cell death occurring through necrotic, apoptotic, and autophagic pathways. There is increasing evidence that reovirus-induced antitumor immunity involving both innate and adaptive responses also contributes to therapeutic efficacy though this discussion is beyond the scope of this article. Here we review our current understanding of the mechanism of oncolysis contributing to the broad anticancer activity of reovirus. Further understanding of reovirus oncolysis is critical in enhancing the clinical development and efficacy of reovirus.

  12. Three Different Pathways Prevent Chromosome Segregation in the Presence of DNA Damage or Replication Stress in Budding Yeast.

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    Gloria Palou

    2015-09-01

    Full Text Available A surveillance mechanism, the S phase checkpoint, blocks progression into mitosis in response to DNA damage and replication stress. Segregation of damaged or incompletely replicated chromosomes results in genomic instability. In humans, the S phase checkpoint has been shown to constitute an anti-cancer barrier. Inhibition of mitotic cyclin dependent kinase (M-CDK activity by Wee1 kinases is critical to block mitosis in some organisms. However, such mechanism is dispensable in the response to genotoxic stress in the model eukaryotic organism Saccharomyces cerevisiae. We show here that the Wee1 ortholog Swe1 does indeed inhibit M-CDK activity and chromosome segregation in response to genotoxic insults. Swe1 dispensability in budding yeast is the result of a redundant control of M-CDK activity by the checkpoint kinase Rad53. In addition, our results indicate that Swe1 is an effector of the checkpoint central kinase Mec1. When checkpoint control on M-CDK and on Pds1/securin stabilization are abrogated, cells undergo aberrant chromosome segregation.

  13. Soluble histone H2AX is induced by DNA replication stress and sensitizes cells to undergo apoptosis

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    Duensing Stefan

    2008-07-01

    Full Text Available Abstract Background Chromatin-associated histone H2AX is a key regulator of the cellular responses to DNA damage. However, non-nucleosomal functions of histone H2AX are poorly characterized. We have recently shown that soluble H2AX can trigger apoptosis but the mechanisms leading to non-chromatin-associated H2AX are unclear. Here, we tested whether stalling of DNA replication, a common event in cancer cells and the underlying mechanism of various chemotherapeutic agents, can trigger increased soluble H2AX. Results Transient overexpression of H2AX was found to lead to a detectable fraction of soluble H2AX and was associated with increased apoptosis. This effect was enhanced by the induction of DNA replication stress using the DNA polymerase α inhibitor aphidicolin. Cells manipulated to stably express H2AX did not contain soluble H2AX, however, short-term treatment with aphidicolin (1 h resulted in detectable amounts of H2AX in the soluble nuclear fraction and enhanced apoptosis. Similarly, soluble endogenous H2AX was detected under these conditions. We found that excessive soluble H2AX causes chromatin aggregation and inhibition of ongoing gene transcription as evidenced by the redistribution and/or loss of active RNA polymerase II as well as the transcriptional co-activators CBP and p300. Conclusion Taken together, these results show that DNA replication stress rapidly leads to increased soluble H2AX and that non-chromatin-associated H2AX can sensitize cells to undergo apoptosis. Our findings encourage further studies to explore H2AX and the cellular pathways that control its expression as anti-cancer drug targets.

  14. Inflammation-and stress-related signaling pathways in hepatocarcinogenesis

    Institute of Scientific and Technical Information of China (English)

    Hayato Nakagawa; Shin Maeda

    2012-01-01

    It has been established that cancer can be promoted and exacerbated by inflammation.Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide,and its long-term prognosis remains poor.Although HCC is a complex and heterogeneous tumor with several genomic mutations,it usually develops in the context of chronic liver damage and inflammation,suggesting that understanding the mechanism(s) of inflammation-mediated hepatocarcinogenesis is essential for the treatment and prevention of HCC.Chronic liver damage induces a persistent cycle of necroinflammation and hepatocyte regeneration,resulting in genetic mutations in hepatocytes and expansion of initiated cells,eventually leading to HCC development.Recently,several inflammation-and stress-related signaling pathways have been identified as key players in these processes,which include the nuclear factorκB,signal transducer and activator of transcription,and stress-activated mitogen-activated protein kinase pathways.Although these pathways may suggest potential therapeutic targets,they have a wide range of functions and complex crosstalk occurs among them.This review focuses on recent advances in our understanding of the roles of these signaling pathways in hepatocarcinogenesis.

  15. An epigenome-wide association meta-analysis of prenatal maternal stress in neonates: A model approach for replication.

    Science.gov (United States)

    Rijlaarsdam, Jolien; Pappa, Irene; Walton, Esther; Bakermans-Kranenburg, Marian J; Mileva-Seitz, Viara R; Rippe, Ralph C A; Roza, Sabine J; Jaddoe, Vincent W V; Verhulst, Frank C; Felix, Janine F; Cecil, Charlotte A M; Relton, Caroline L; Gaunt, Tom R; McArdle, Wendy; Mill, Jonathan; Barker, Edward D; Tiemeier, Henning; van IJzendoorn, Marinus H

    2016-01-01

    Prenatal maternal stress exposure has been associated with neonatal differential DNA methylation. However, the available evidence in humans is largely based on candidate gene methylation studies, where only a few CpG sites were evaluated. The aim of this study was to examine the association between prenatal exposure to maternal stress and offspring genome-wide cord blood methylation using different methods. First, we conducted a meta-analysis and follow-up pathway analyses. Second, we used novel region discovery methods [i.e., differentially methylated regions (DMRs) analyses]. To this end, we used data from two independent population-based studies, the Generation R Study (n = 912) and the Avon Longitudinal Study of Parents and Children (ALSPAC, n = 828), to (i) measure genome-wide DNA methylation in cord blood and (ii) extract a prenatal maternal stress composite. The meta-analysis (ntotal = 1,740) revealed no epigenome-wide (meta P meta-analysis (meta P meta-analysis, the current study indicates that there are no large effects of prenatal maternal stress exposure on neonatal DNA methylation. Such replication efforts are essential in the search for robust associations, whether derived from candidate gene methylation or epigenome-wide studies.

  16. Activation of PERK signaling attenuates Abeta-mediated ER stress.

    Directory of Open Access Journals (Sweden)

    Do Yeon Lee

    Full Text Available Alzheimer's disease (AD is characterized by the deposition of aggregated beta-amyloid (Abeta, which triggers a cellular stress response called the unfolded protein response (UPR. The UPR signaling pathway is a cellular defense system for dealing with the accumulation of misfolded proteins but switches to apoptosis when endoplasmic reticulum (ER stress is prolonged. ER stress is involved in neurodegenerative diseases including AD, but the molecular mechanisms of ER stress-mediated Abeta neurotoxicity still remain unknown. Here, we show that treatment of Abeta triggers the UPR in the SK-N-SH human neuroblastoma cells. Abeta mediated UPR pathway accompanies the activation of protective pathways such as Grp78/Bip and PERK-eIF2alpha pathway, as well as the apoptotic pathways of the UPR such as CHOP and caspase-4. Knockdown of PERK enhances Abeta neurotoxicity through reducing the activation of eIF2alpha and Grp8/Bip in neurons. Salubrinal, an activator of the eIF2alpha pathway, significantly increased the Grp78/Bip ER chaperone resulted in attenuating caspase-4 dependent apoptosis in Abeta treated neurons. These results indicate that PERK-eIF2alpha pathway is a potential target for therapeutic applications in neurodegenerative diseases including AD.

  17. Small molecule activators of SIRT1 replicate signaling pathways triggered by calorie restriction in vivo

    Directory of Open Access Journals (Sweden)

    Lavu Siva

    2009-03-01

    Full Text Available Abstract Background Calorie restriction (CR produces a number of health benefits and ameliorates diseases of aging such as type 2 diabetes. The components of the pathways downstream of CR may provide intervention points for developing therapeutics for treating diseases of aging. The NAD+-dependent protein deacetylase SIRT1 has been implicated as one of the key downstream regulators of CR in yeast, rodents, and humans. Small molecule activators of SIRT1 have been identified that exhibit efficacy in animal models of diseases typically associated with aging including type 2 diabetes. To identify molecular processes induced in the liver of mice treated with two structurally distinct SIRT1 activators, SIRT501 (formulated resveratrol and SRT1720, for three days, we utilized a systems biology approach and applied Causal Network Modeling (CNM on gene expression data to elucidate downstream effects of SIRT1 activation. Results Here we demonstrate that SIRT1 activators recapitulate many of the molecular events downstream of CR in vivo, such as enhancing mitochondrial biogenesis, improving metabolic signaling pathways, and blunting pro-inflammatory pathways in mice fed a high fat, high calorie diet. Conclusion CNM of gene expression data from mice treated with SRT501 or SRT1720 in combination with supporting in vitro and in vivo data demonstrates that SRT501 and SRT1720 produce a signaling profile that mirrors CR, improves glucose and insulin homeostasis, and acts via SIRT1 activation in vivo. Taken together these results are encouraging regarding the use of small molecule activators of SIRT1 for therapeutic intervention into type 2 diabetes, a strategy which is currently being investigated in multiple clinical trials.

  18. Human Immunodeficiency Virus Type 1 Vpr Induces DNA Replication Stress In Vitro and In Vivo▿

    Science.gov (United States)

    Zimmerman, Erik S.; Sherman, Michael P.; Blackett, Jana L.; Neidleman, Jason A.; Kreis, Christophe; Mundt, Pamela; Williams, Samuel A.; Warmerdam, Maria; Kahn, James; Hecht, Frederick M.; Grant, Robert M.; de Noronha, Carlos M. C.; Weyrich, Andrew S.; Greene, Warner C.; Planelles, Vicente

    2006-01-01

    The human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) causes cell cycle arrest in G2. Vpr-expressing cells display the hallmarks of certain forms of DNA damage, specifically activation of the ataxia telangiectasia mutated and Rad3-related kinase, ATR. However, evidence that Vpr function is relevant in vivo or in the context of viral infection is still lacking. In the present study, we demonstrate that HIV-1 infection of primary, human CD4+ lymphocytes causes G2 arrest in a Vpr-dependent manner and that this response requires ATR, as shown by RNA interference. The event leading to ATR activation in CD4+ lymphocytes is the accumulation of replication protein A in nuclear foci, an indication that Vpr likely induces stalling of replication forks. Primary macrophages are refractory to ATR activation by Vpr, a finding that is consistent with the lack of detectable ATR, Rad17, and Chk1 protein expression in these nondividing cells. These observations begin to explain the remarkable resilience of macrophages to HIV-1-induced cytopathicity. To study the in vivo consequences of Vpr function, we isolated CD4+ lymphocytes from HIV-1-infected individuals and interrogated the cell cycle status of anti-p24Gag-immunoreactive cells. We report that infected cells in vivo display an aberrant cell cycle profile whereby a majority of cells have a 4N DNA content, consistent with the onset of G2 arrest. PMID:16956949

  19. CtrA response regulator binding to the Caulobacter chromosome replication origin is required during nutrient and antibiotic stress as well as during cell cycle progression.

    Science.gov (United States)

    Bastedo, D Patrick; Marczynski, Gregory T

    2009-04-01

    The Caulobacter crescentus chromosome replication origin (Cori) has five binding sites for CtrA, an OmpR/PhoB family 'response regulator'. CtrA is degraded in replicating 'stalked' cells but is abundant in the non-replicating 'swarmer' cells, where it was proposed to repress replication by binding to Cori. We systematically mutated all Cori CtrA binding sites, and examined their consequences in the contexts of autonomous Cori-plasmid replication and in the natural chromosome locus. Remarkably, the C. crescentus chromosome tolerates severe mutations in all five CtrA binding sites, demonstrating that CtrA is not essential for replication. Further physiological and cell cycle experiments more rigorously supported the original hypothesis that CtrA represses replication. However, our experiments argued against another hypothesis that residual and/or replenished CtrA protein in stalked cells might prevent extra or unscheduled chromosome replication before cell division. Surprisingly, we also demonstrated that Cori CtrA binding sites are very advantageous and can become essential when cells encounter nutrients and antibiotics. Therefore, the CtrA cell cycle regulator co-ordinates replication with viable cell growth in stressful and rapidly changing environments. We argue that this new role for CtrA provided the primary selective pressure for evolving control by CtrA.

  20. FBH1 Catalyzes Regression of Stalled Replication Forks

    DEFF Research Database (Denmark)

    Fugger, Kasper; Mistrik, Martin; Neelsen, Kai J

    2015-01-01

    DNA replication fork perturbation is a major challenge to the maintenance of genome integrity. It has been suggested that processing of stalled forks might involve fork regression, in which the fork reverses and the two nascent DNA strands anneal. Here, we show that FBH1 catalyzes regression...... a model whereby FBH1 promotes early checkpoint signaling by remodeling of stalled DNA replication forks....... of a model replication fork in vitro and promotes fork regression in vivo in response to replication perturbation. Cells respond to fork stalling by activating checkpoint responses requiring signaling through stress-activated protein kinases. Importantly, we show that FBH1, through its helicase activity...

  1. Physiological stress mediates the honesty of social signals.

    Directory of Open Access Journals (Sweden)

    Gary R Bortolotti

    Full Text Available BACKGROUND: Extravagant ornaments used as social signals evolved to advertise their bearers' quality. The Immunocompetence Handicap Hypothesis proposes that testosterone-dependent ornaments reliably signal health and parasite resistance; however, empirical studies have shown mixed support. Alternatively, immune function and parasite resistance may be indirectly or directly related to glucocorticoid stress hormones. We propose that an understanding of the interplay between the individual and its environment, particularly how they cope with stressors, is crucial for understanding the honesty of social signals. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed corticosterone deposited in growing feathers as an integrated measure of hypothalamic-pituitary-adrenal activity in a wild territorial bird, the red grouse Lagopus lagopus scoticus. We manipulated two key, interrelated components, parasites and testosterone, which influence both ornamentation and fitness. Birds were initially purged of parasites, and later challenged with parasites or not, while at the same time being given testosterone or control implants, using a factorial experimental design. At the treatment level, testosterone enhanced ornamentation, while parasites reduced it, but only in males not implanted with testosterone. Among individuals, the degree to which both parasites and testosterone had an effect was strongly dependent on the amount of corticosterone in the feather grown during the experiment. The more stressors birds had experienced (i.e., higher corticosterone, the more parasites developed, and the less testosterone enhanced ornamentation. CONCLUSIONS/SIGNIFICANCE: With this unique focus on the individual, and a novel, integrative, measure of response to stressors, we show that ornamentation is ultimately a product of the cumulative physiological response to environmental challenges. These findings lead toward a more realistic concept of honesty in signaling as well as a

  2. Chronic stress accelerates pancreatic cancer growth and invasion: a critical role for beta-adrenergic signaling in the pancreatic microenvironment.

    Science.gov (United States)

    Kim-Fuchs, Corina; Le, Caroline P; Pimentel, Matthew A; Shackleford, David; Ferrari, Davide; Angst, Eliane; Hollande, Frédéric; Sloan, Erica K

    2014-08-01

    Pancreatic cancer cells intimately interact with a complex microenvironment that influences pancreatic cancer progression. The pancreas is innervated by fibers of the sympathetic nervous system (SNS) and pancreatic cancer cells have receptors for SNS neurotransmitters which suggests that pancreatic cancer may be sensitive to neural signaling. In vitro and non-orthotopic in vivo studies showed that neural signaling modulates tumour cell behavior. However the effect of SNS signaling on tumor progression within the pancreatic microenvironment has not previously been investigated. To address this, we used in vivo optical imaging to non-invasively track growth and dissemination of primary pancreatic cancer using an orthotopic mouse model that replicates the complex interaction between pancreatic tumor cells and their microenvironment. Stress-induced neural activation increased primary tumor growth and tumor cell dissemination to normal adjacent pancreas. These effects were associated with increased expression of invasion genes by tumor cells and pancreatic stromal cells. Pharmacological activation of β-adrenergic signaling induced similar effects to chronic stress, and pharmacological β-blockade reversed the effects of chronic stress on pancreatic cancer progression. These findings indicate that neural β-adrenergic signaling regulates pancreatic cancer progression and suggest β-blockade as a novel strategy to complement existing therapies for pancreatic cancer.

  3. Economic Pressure in African American Families: A Replication and Extension of the Family Stress Model.

    Science.gov (United States)

    Conger, Rand D.; Wallace, Lora Ebert; Sun, Yumei; Simons, Ronald L.; McLoyd, Vonnie C.; Brody, Gene H.

    2002-01-01

    Evaluated applicability of family stress model of economic hardship for understanding economic influences on child development among African American families with a 10- or 11-year-old child. Found that economic hardship positively related to economic pressure in families, and to emotional distress of caregivers, which in turn damaged the…

  4. A cytoplasmic activator of DNA replication is involved in signal transduction in antigen-specific T cell lines.

    Science.gov (United States)

    Wong, R L; Clark, R B; Gutowski, J K; Katz, M E; Fresa, K L; Cohen, S

    1990-05-01

    Cytoplasmic extracts prepared from T cell lines undergoing antigen-specific, interleukin-2 (IL-2)-dependent proliferation were tested for their ability to induce DNA synthesis in isolated, quiescent nuclei. A tetanus toxoid (TET)-specific T cell line, established from peripheral blood of a normal human volunteer, was stimulated in the presence of relevant antigen and 1 unit/ml IL-2. Cytoplasmic extracts prepared from these cells were capable of inducing DNA synthesis in isolated, quiescent nuclei. The ability of cytoplasmic extracts to induce DNA synthesis in isolated, quiescent nuclei. The ability of cytoplasmic extracts to induce DNA synthesis in isolated nuclei correlated positively with the degree of proliferation induced in these cells. In contrast, incubation of this T cell line in the absence of antigen failed to induce proliferation and cytoplasmic extracts prepared from these cells induced little to no DNA synthesis in isolated, quiescent nuclei. The factor present in the cytoplasm of T cells stimulated with relevant antigen in the presence of IL-2 is similar, if not identical, to a factor which we have previously demonstrated in cytoplasmic extracts prepared from transformed lymphoblastoid cell lines and from mitogenically stimulated normal human peripheral blood mononuclear cells. This factor, which we have called activator of DNA replication (ADR) is a heat-labile protein, and is inactivated by treatment with protease inhibitors, including aprotinin. The ability of cytoplasmic extracts from T cells undergoing antigen-specific, IL-2-dependent proliferation to induce DNA synthesis in isolated, quiescent nuclei was markedly inhibited in the presence of aprotinin, providing strong evidence that a cytoplasmic activator of DNA replication, ADR, is involved in the signal transduction process for antigen-specific, IL-2-dependent T cell proliferation. ADR may represent a common intracellular mediator of DNA synthesis in activated and transformed lymphocytes.

  5. Intracellular expression of IRF9 Stat fusion protein overcomes the defective Jak-Stat signaling and inhibits HCV RNA replication

    Directory of Open Access Journals (Sweden)

    Balart Luis A

    2010-10-01

    Full Text Available Abstract Interferon alpha (IFN-α binds to a cell surface receptor that activates the Jak-Stat signaling pathway. A critical component of this pathway is the translocation of interferon stimulated gene factor 3 (a complex of three proteins Stat1, Stat2 and IRF9 to the nucleus to activate antiviral genes. A stable sub-genomic replicon cell line resistant to IFN-α was developed in which the nuclear translocation of Stat1 and Stat2 proteins was prevented due to the lack of phosphorylation; whereas the nuclear translocation of IRF9 protein was not affected. In this study, we sought to overcome defective Jak-Stat signaling and to induce an antiviral state in the IFN-α resistant replicon cell line by developing a chimera IRF9 protein fused with the trans activating domain (TAD of either a Stat1 (IRF9-S1C or Stat2 (IRF9-S2C protein. We show here that intracellular expression of fusion proteins using the plasmid constructs of either IRF9-S1C or IRF9-S2C, in the IFN-α resistant cells, resulted in an increase in Interferon Stimulated Response Element (ISRE luciferase promoter activity and significantly induced HLA-1 surface expression. Moreover, we show that transient transfection of IRF9-S1C or IRF9-S2C plasmid constructs into IFN-α resistant replicon cells containing sub-genomic HCV1b and HCV2a viruses resulted in an inhibition of viral replication and viral protein expression independent of IFN-α treatment. The results of this study indicate that the recombinant fusion proteins of IRF9-S1C, IRF9-S2C alone, or in combination, have potent antiviral properties against the HCV in an IFN-α resistant cell line with a defective Jak-Stat signaling.

  6. The Aurora-B-dependent NoCut checkpoint prevents damage of anaphase bridges after DNA replication stress.

    Science.gov (United States)

    Amaral, Nuno; Vendrell, Alexandre; Funaya, Charlotta; Idrissi, Fatima-Zahra; Maier, Michael; Kumar, Arun; Neurohr, Gabriel; Colomina, Neus; Torres-Rosell, Jordi; Geli, María-Isabel; Mendoza, Manuel

    2016-05-01

    Anaphase chromatin bridges can lead to chromosome breakage if not properly resolved before completion of cytokinesis. The NoCut checkpoint, which depends on Aurora B at the spindle midzone, delays abscission in response to chromosome segregation defects in yeast and animal cells. How chromatin bridges are detected, and whether abscission inhibition prevents their damage, remain key unresolved questions. We find that bridges induced by DNA replication stress and by condensation or decatenation defects, but not dicentric chromosomes, delay abscission in a NoCut-dependent manner. Decatenation and condensation defects lead to spindle stabilization during cytokinesis, allowing bridge detection by Aurora B. NoCut does not prevent DNA damage following condensin or topoisomerase II inactivation; however, it protects anaphase bridges and promotes cellular viability after replication stress. Therefore, the molecular origin of chromatin bridges is critical for activation of NoCut, which plays a key role in the maintenance of genome stability after replicative stress.

  7. Mitochondrial Stress Signalling: HTRA2 and Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Enrico Desideri

    2012-01-01

    Full Text Available Mitochondria are cellular energy generators whose activity requires a continuous supply of oxygen. Recent genetic analysis has suggested that defects in mitochondrial quality control may be key factors in the development of Parkinson’s disease (PD. Mitochondria have a crucial role in supplying energy to the brain, and their deterioration can affect the function and viability of neurons, contributing to neurodegeneration. These organelles can sow the seeds of their own demise because they generate damaging oxygen-free radicals as a byproduct of their intrinsic physiological functions. Mitochondria have therefore evolved specific molecular quality control mechanisms to compensate for the action of damaging agents such as oxygen-free radicals. PTEN-induced putative kinase 1 (PINK1 and high-temperature-regulated A2 (HTRA2, a mitochondrial protease, have recently been proposed to be key modulators of mitochondrial molecular quality control. Here, we review some of the most recent advances in our understanding of mitochondria stress-control pathways, focusing on how signalling by the p38 stress kinase pathway may regulate mitochondrial stress by modulating the activity of HTRA2 via PINK1 and cyclin-dependent kinase 5 (CDK5. We also propose how defects in this pathway may contribute to PD.

  8. Calcium signaling alterations, oxidative stress, and autophagy in aging.

    Science.gov (United States)

    Ureshino, Rodrigo Portes; Rocha, Katiucha Karolina; Lopes, Guiomar Silva; Bincoletto, Cláudia; Smaili, Soraya Soubhi

    2014-07-01

    Aging is a multi-factorial process that may be associated with several functional and structural deficits which can evolve into degenerative diseases. In this review, we present data that may depict an expanded view of molecular aging theories, beginning with the idea that reactive oxygen species (ROS) are the major effectors in this process. In addition, we have correlated the importance of autophagy as a neuroprotective mechanism and discussed a link between age-related molecules, Ca(2+) signaling, and oxidative stress. There is evidence suggesting that alterations in Ca(2+) homeostasis, including mitochondrial Ca(2+) overload and alterations in electron transport chain (ETC) complexes, which increase cell vulnerability, are linked to oxidative stress in aging. As much as Ca(2+) signaling is altered in aged cells, excess ROS can be produced due to an ineffective coupling of mitochondrial respiration. Damaged mitochondria might not be removed by the macroautophagic system, which is hampered in aging by lipofuscin accumulation, boosting ROS generation, damaging DNA, and, ultimately, leading to apoptosis. This process can lead to altered protein expression (such as p53, Sirt1, and IGF-1) and progress to cell death. This cycle can lead to increased cell vulnerability in aging and contribute to an increased susceptibility to degenerative processes. A better understanding of Ca(2+) signaling and molecular aging alterations is important for preventing apoptosis in age-related diseases. In addition, caloric restriction, resveratrol and autophagy modulation appear to be predominantly cytoprotective, and further studies of this process are promising in age-related disease therapeutics.

  9. Regulation of SUMO2 Target Proteins by the Proteasome in Human Cells Exposed to Replication Stress

    DEFF Research Database (Denmark)

    Bursomanno, Sara; McGouran, Joanna F; Kessler, Benedikt M

    2015-01-01

    In human cells, SUMO2 is predominantly conjugated to target proteins in response to cellular stress. Previous studies suggested that proteins conjugated to SUMO2, but not to SUMO1, could be regulated by the ubiquitin-mediated proteasome system. Hence, we set out to understand the role of the prot......In human cells, SUMO2 is predominantly conjugated to target proteins in response to cellular stress. Previous studies suggested that proteins conjugated to SUMO2, but not to SUMO1, could be regulated by the ubiquitin-mediated proteasome system. Hence, we set out to understand the role...... of genome instability, which is suggested to drive tumorigenesis and possibly aging, our data will facilitate future functional studies in the fields of DNA metabolism and cancer biology....

  10. Genetic and biochemical evidences reveal novel insights into the mechanism underlying Saccharomyces cerevisiae Sae2-mediated abrogation of DNA replication stress

    Indian Academy of Sciences (India)

    INDRAJEET GHODKE; K MUNIYAPPA

    2016-12-01

    In Saccharomyces cerevisiae, the Mre11-Rad50-Xrs2 (MRX) protein complex plays pivotal roles in double-strandbreak (DSB) repair, replication stress and telomere length maintenance. Another protein linked to DSB repair is Sae2,which regulates MRX persistence at DSBs. However, very little is known about its role in DNA replication stress andrepair. Here, we reveal a crucial role for Sae2 in DNA replication stress. We show that different mutant alleles of SAE2cause hypersensitivity to genotoxic agents, and when combined with Δmre11 or nuclease-defective mre11 mutantalleles, the double mutants are considerably more sensitive suggesting that the sae2 mutations synergize with mre11mutations. Biochemical studies demonstrate that Sae2 exists as a dimer in solution, associates preferentially withsingle-stranded and branched DNA structures, exhibits structure-specific endonuclease activity and cleaves thesesubstrates from the 5′ end. Furthermore, we show that the nuclease activity is indeed intrinsic to Sae2. Interestingly,sae2G270D protein possesses DNA-binding activity, but lacks detectable nuclease activity. Altogether, our data suggesta direct role for Sae2 nuclease activity in processing of the DNA structures that arise during replication and DNAdamage and provide insights into the mechanism underlying Mre11-Sae2-mediated abrogation of replication stress-relateddefects in S. cerevisiae.

  11. Rad53-Mediated Regulation of Rrm3 and Pif1 DNA Helicases Contributes to Prevention of Aberrant Fork Transitions under Replication Stress

    Directory of Open Access Journals (Sweden)

    Silvia Emma Rossi

    2015-10-01

    Full Text Available Replication stress activates the Mec1ATR and Rad53 kinases. Rad53 phosphorylates nuclear pores to counteract gene gating, thus preventing aberrant transitions at forks approaching transcribed genes. Here, we show that Rrm3 and Pif1, DNA helicases assisting fork progression across pausing sites, are detrimental in rad53 mutants experiencing replication stress. Rrm3 and Pif1 ablations rescue cell lethality, chromosome fragmentation, replisome-fork dissociation, fork reversal, and processing in rad53 cells. Through phosphorylation, Rad53 regulates Rrm3 and Pif1; phospho-mimicking rrm3 mutants ameliorate rad53 phenotypes following replication stress without affecting replication across pausing elements under normal conditions. Hence, the Mec1-Rad53 axis protects fork stability by regulating nuclear pores and DNA helicases. We propose that following replication stress, forks stall in an asymmetric conformation by inhibiting Rrm3 and Pif1, thus impeding lagging strand extension and preventing fork reversal; conversely, under unperturbed conditions, the peculiar conformation of forks encountering pausing sites would depend on active Rrm3 and Pif1.

  12. Epigenetic Signals on Plant Adaptation: A Biotic Stress Perspective.

    Science.gov (United States)

    Neto, José Ribamar Costa Ferreira; da Silva, Manassés Daniel; Pandolfi, Valesca; Crovella, Sérgio; Benko-Iseppon, Ana Maria; Kido, Ederson Akio

    2016-07-24

    For sessile organisms such as plants, regulatory mechanisms of gene expression are vital, since they remain exposed to climatic and biological threats. Thus, they have to face hazards with instantaneous reorganization of their internal environment. For this purpose, besides the use of transcription factors, the participation of chromatin as an active factor in the regulation of transcription is crucial. Chemical changes in chromatin structure affect the accessibility of the transcriptional machinery and acting in signaling, engaging/inhibiting factors that participate in the transcription processes. Mechanisms in which gene expression undergoes changes without the occurrence of DNA gene mutations in the monomers that make up DNA, are understood as epigenetic phenomena. These include (1) post-translational modifications of histones, which results in stimulation or repression of gene activity and (2) cytosine methylation in the promoter region of individual genes, both preventing access of transcriptional activators as well as signaling the recruitment of repressors. There is evidence that such modifications can pass on to subsequent generations of daughter cells and even generations of individuals. However, reports indicate that they persist only in the presence of a stressor factor (or an inductor of the above-mentioned modifications). In its absence, these modifications weaken or lose heritability, being eliminated in the next few generations. In this review, it is argued how epigenetic signals influence gene regulation, the mechanisms involved and their participation in processes of resistance to biotic stresses, controlling processes of the plant immune system.

  13. Rec-8 dimorphism affects longevity, stress resistance and X-chromosome nondisjunction in C. elegans, and replicative lifespan in yeast

    Directory of Open Access Journals (Sweden)

    Srinivas eAyyadevara

    2014-08-01

    Full Text Available A quantitative trait locus (QTL in the nematode C. elegans, lsq4, was recently implicated by mapping longevity genes. QTLs for lifespan and 3 stress-resistance traits coincided within a span of <300 kbp, later narrowed to <200 kbp. A single gene in this interval is now shown to modulate all lsq4-associated traits. Full-genome analysis of transcript levels indicates that lsq4 contains a dimorphic gene governing expression of sperm-specific genes, suggesting effects on spermatogenesis. Quantitation of allele-specific transcripts encoded within the lsq4 interval revealed significant, 2- to 15-fold expression differences for 10 of 33 genes. Fourteen genes, implicated by both position and expression, were tested for RNA-interference effects on QTL-linked traits. In a strain carrying the shorter-lived allele, knockdown of rec-8 (encoding a meiotic cohesin reduced its transcripts 4-fold, to a level similar to the longer-lived strain, and extended lifespan 25–26% whether begun before fertilization or at maturity. The short-lived lsq4 allele also conferred sensitivity to oxidative and thermal stresses, and lower male frequency, traits reversed uniquely by rec-8 knockdown. A strain bearing the longer-lived lsq4 allele, differing from the short-lived strain at <0.3% of its genome, derived no lifespan or stress-survival benefit from rec-8 knockdown. We consider two possible explanations: high rec-8 expression may include increased leaky expression in mitotic cells, leading to deleterious destabilization of somatic genomes; or REC-8 may act entirely in germ-line meiotic cells to reduce aberrations such as nondisjunction, thereby blunting a stress-resistance response mediated by innate immunity. Replicative lifespan was extended 20% in haploid S. cerevisiae (BY4741 by deletion of REC8, orthologous to nematode rec-8, implying that REC8 disruption of mitotic-cell survival is widespread, reflecting antagonistic pleiotropy and/or balancing selection.

  14. Cyclosporin a inhibits rotavirus replication and restores interferon-beta signaling pathway in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Zigang Shen

    Full Text Available Rotavirus (RV is the most common cause of severe diarrhea among infants and young children. Currently, there is no specific drug available against rotavirus, largely due to the lack of an ideal target molecule which has hampered drug development. Our previous studies have revealed that cyclosporin A (CsA might be potentially useful as an anti-RV drug. We therefore used both cellular and mouse models to study the immunological safety and effectiveness of CsA as an anti-RV drug. We found that CsA treatment of HT-29 cells before, during, and after viral infection efficiently inhibited Wa strain RV replication and restored IFN-β expression in a HT-29 cell line model. Exploring the underlying mechanisms showed that CsA promoted Interferon Regulatory Factor-5 (IRF-5 expression (a key positive regulator of the type I IFN signaling pathway, but not IRF-1, IRF-3, or IRF-7. Additionally, CsA inhibited SOCS-1 expression (the key negative regulator of IFN-α/β, but not SOCS-2 or SOCS-3. The antiviral effect of CsA was confirmed in an RV-infected neonatal mouse model by evaluation of antigen clearance and assessment of changes in intestinal tissue pathology. Also, no differences in T cell frequency or proliferation between the CsA- and vehicle-treated groups were observed. Thus, both our in vitro and in vivo findings suggest that CsA, through modulating the expression of key regulators in IFN signaling pathway, promote type I IFN-based intracellular innate immunity in RV host cells. These findings suggest that CsA may be a useful candidate to develop a new anti-RV strategy, although further evaluation and characterization of CsA on RV-induced diarrhea are warranted.

  15. Aedes Aegypti saliva enhances chikungunya virus replication in human skin fibroblasts via inhibition of the type I interferon signaling pathway.

    Science.gov (United States)

    Wichit, Sineewanlaya; Diop, Fodé; Hamel, Rodolphe; Talignani, Loïc; Ferraris, Pauline; Cornelie, Sylvie; Liegeois, Florian; Thomas, Frédéric; Yssel, Hans; Missé, Dorothée

    2017-09-01

    Chikungunya virus (CHIKV) transmission occurs through the bite of an infected Aedes mosquito which injects virus-containing saliva into the skin of the human host during blood feeding. In the present study, we have determined the effect of Aedes aegypti saliva on CHIKV replication in human skin fibroblasts, a major cell type for viral entry, which mimics the events that occur during natural transmission. A significant increase in the expression of viral transcripts and infectious viral particles was observed in fibroblasts infected with CHIKV in the presence of saliva, as compared with those infected with virus alone. CHIKV-infected human fibroblasts were found to express significantly increased levels of various type I IFN-responsive genes, as demonstrated by specific PCR array analysis. In contrast, the expression of these genes was markedly decreased in cells infected with CHIKV in the presence of mosquito saliva. Moreover, Western blotting analysis revealed that STAT2 and its phosphorylated form were down-regulated in the presence of mosquito saliva. Our data demonstrate for the first time the significance of Aedes aegypti saliva in promoting CHIKV infection via down-regulation of several type I IFN-responsive genes in infected human skin fibroblasts via the JAK-STAT signaling pathway. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Computing a Synthetic Chronic Psychosocial Stress Measurement in Multiple Datasets and its Application in the Replication of G × E Interactions of the EBF1 Gene.

    Science.gov (United States)

    Singh, Abanish; Babyak, Michael A; Brummett, Beverly H; Jiang, Rong; Watkins, Lana L; Barefoot, John C; Kraus, William E; Shah, Svati H; Siegler, Ilene C; Hauser, Elizabeth R; Williams, Redford B

    2015-09-01

    Chronic psychosocial stress adversely affects health and is associated with the development of disease [Williams, 2008]. Systematic epidemiological and genetic studies are needed to uncover genetic variants that interact with stress to modify metabolic responses across the life cycle that are the proximal contributors to the development of cardiovascular disease and precipitation of acute clinical events. Among the central challenges in the field are to perform and replicate gene-by-environment (G × E) studies. The challenge of measurement of individual experience of psychosocial stress is magnified in this context. Although many research datasets exist that contain genotyping and disease-related data, measures of psychosocial stress are often either absent or vary substantially across studies. In this paper, we provide an algorithm to create a synthetic measure of chronic psychosocial stress across multiple datasets, applying a consistent criterion that uses proxy indicators of stress components. We validated the computed scores of chronic psychosocial stress by observing moderately strong and significant correlations with the self-rated chronic psychosocial stress in the Multi-Ethnic Study of Atherosclerosis Cohort (Rho = 0.23, P psychosocial stress variable by providing three additional replications of our previous finding of gene-by-stress interaction with central obesity traits [Singh et al., 2015].

  17. Common Chemical Inductors of Replication Stress:  Focus on Cell‐Based Studies

    Directory of Open Access Journals (Sweden)

    Eva Vesela

    2017-02-01

    Full Text Available DNA replication is a highly demanding process regarding the energy and material supply and must be precisely regulated, involving multiple cellular feedbacks. The slowing down or stalling of DNA synthesis and/or replication forks is referred to as replication stress (RS. Owing to the complexity and requirements of replication, a plethora of factors may interfere and challenge the genome stability, cell survival or affect the whole organism. This review outlines chemical compounds that are known inducers of RS and commonly used in laboratory research. These compounds act on replication by direct interaction with DNA causing DNA crosslinks and bulky lesions (cisplatin, chemical interference with the metabolism of deoxyribonucleotide triphosphates (hydroxyurea, direct inhibition of the activity of replicative DNA polymerases (aphidicolin and interference with enzymes dealing with topological DNA stress (camptothecin, etoposide. As a variety of mechanisms can induce RS, the responses of mammalian cells also vary. Here, we review the activity and mechanism of action of these compounds based on recent knowledge, accompanied by examples of induced phenotypes, cellular readouts and commonly used doses.

  18. Replicative Stress and the FHIT Gene: Roles in Tumor Suppression, Genome Stability and Prevention of Carcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Karras, Jenna R.; Paisie, Carolyn A.; Huebner, Kay, E-mail: kay.huebner@osumc.edu [Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University Wexner Medical Center, Columbus, OH 43210 (United States)

    2014-06-04

    The fragile FHIT gene, encompassing the chromosomal fragile site FRA3B, is an early target of DNA damage in precancerous cells. While vulnerable to DNA damage itself, FHIT protein expression is essential to protect from DNA damage-induced cancer initiation and progression by modulating genome stability, oxidative stress and levels of accumulating DNA damage. Thus, FHIT, whose expression is lost or reduced in many human cancers, is a tumor suppressor and genome caretaker whose loss initiates genome instability in preneoplastic lesions. Ongoing studies are seeking more detailed understanding of the role of FHIT in the cellular response to oxidative damage. This review discusses the relationship between FHIT, reactive oxygen species production, and DNA damage in the context of cancer initiation and progression.

  19. FBH1 co-operates with MUS81 in inducing DNA double-strand breaks and cell death following replication stress

    DEFF Research Database (Denmark)

    Fugger, Kasper; Chu, Wai Kit; Haahr, Peter

    2013-01-01

    The molecular events occurring following the disruption of DNA replication forks are poorly characterized, despite extensive use of replication inhibitors such as hydroxyurea in the treatment of malignancies. Here, we identify a key role for the FBH1 helicase in mediating DNA double-strand break...... formation following replication inhibition. We show that FBH1-deficient cells are resistant to killing by hydroxyurea, and exhibit impaired activation of the pro-apoptotic factor p53, consistent with decreased DNA double-strand break formation. Similar findings were obtained in murine ES cells carrying...... disrupted alleles of Fbh1. We also show that FBH1 through its helicase activity co-operates with the MUS81 nuclease in promoting the endonucleolytic DNA cleavage following prolonged replication stress. Accordingly, MUS81 and EME1-depleted cells show increased resistance to the cytotoxic effects...

  20. Early life stress experience may blunt hypothalamic leptin signalling

    Indian Academy of Sciences (India)

    JH LEE; SB YOO; JY KIM; JY LEE; BT KIM; K PARK; JW JAHNG

    2017-03-01

    The aim of this study was to investigate whether neonatal maternal separation (MS) – chronic stress experience inearly life – affects the anorectic efficacy of leptin in the offspring at adolescence. Sprague–Dawley pups wereseparated from the dam daily for 3 h during postnatal day 1–14 or left undisturbed as non-handled controls (NH).NH and MS male pups received an intraperitoneal leptin (100 μg/kg) or saline on postnatal day (PND) 28, and thenfood intake and body weight gain were recorded. The hypothalamic levels of leptin-signalling-related genes,phosphorylated signal transducer and activator of transcription-3 (pSTAT3) and protein-tyrosine phosphatase 1B(PTP1B) were examined at 40 min after a single injection of leptin on PND 39 by immunohistochemistry and Westernblot analysis. Leptin-induced suppressions in food intake and weight gain was observed in NH pups, but not in MS.Leptin increased pSTAT3 in the hypothalamic arcuate nucleus of NH pups, but not of MS. Interestingly, basal levelsof the hypothalamic PTP1B and pSTAT3 were increased in MS pups compared with NH controls. The results suggestthat neonatal MS experience may blunt the anorectic efficacy of leptin later in life, possibly in relation with increasedexpressions of PTP1B and/or pSTAT3 in the hypothalamus.

  1. Early life stress experience may blunt hypothalamic leptin signalling.

    Science.gov (United States)

    Lee, J H; Yoo, S B; Kim, J Y; Lee, J Y; Kim, B T; Park, K; Jahng, J W

    2017-03-01

    The aim of this study was to investigate whether neonatal maternal separation (MS) - chronic stress experience in early life - affects the anorectic efficacy of leptin in the offspring at adolescence. Sprague-Dawley pups were separated from the dam daily for 3 h during postnatal day 1-14 or left undisturbed as non-handled controls (NH). NH and MS male pups received an intraperitoneal leptin (100 μg/kg) or saline on postnatal day (PND) 28, and then food intake and body weight gain were recorded. The hypothalamic levels of leptin-signalling-related genes, phosphorylated signal transducer and activator of transcription-3 (pSTAT3) and protein-tyrosine phosphatase 1B (PTP1B) were examined at 40 min after a single injection of leptin on PND 39 by immunohistochemistry and Western blot analysis. Leptin-induced suppressions in food intake and weight gain was observed in NH pups, but not in MS. Leptin increased pSTAT3 in the hypothalamic arcuate nucleus of NH pups, but not of MS. Interestingly, basal levels of the hypothalamic PTP1B and pSTAT3 were increased in MS pups compared with NH controls. The results suggest that neonatal MS experience may blunt the anorectic efficacy of leptin later in life, possibly in relation with increased expressions of PTP1B and/or pSTAT3 in the hypothalamus.

  2. Apoptotic and stress signaling markers are augmented in preeclamptic placenta and umbilical cord

    Directory of Open Access Journals (Sweden)

    Syeda H. Afroze

    2016-12-01

    Conclusions: Apoptotic and stress signaling are augmented in preE placenta and cord tissue that alter the intrauterine environment and activates the detrimental signaling that is transported to fetus.

  3. DNA replication and cancer

    DEFF Research Database (Denmark)

    Boyer, Anne-Sophie; Walter, David; Sørensen, Claus Storgaard

    2016-01-01

    A dividing cell has to duplicate its DNA precisely once during the cell cycle to preserve genome integrity avoiding the accumulation of genetic aberrations that promote diseases such as cancer. A large number of endogenous impacts can challenge DNA replication and cells harbor a battery of pathways...... causing DNA replication stress and genome instability. Further, we describe cellular and systemic responses to these insults with a focus on DNA replication restart pathways. Finally, we discuss the therapeutic potential of exploiting intrinsic replicative stress in cancer cells for targeted therapy....

  4. Asthma and influenza virus infection:focusing on cell death and stress pathways in influenza virus replication.

    Science.gov (United States)

    Yeganeh, Behzad; Rezaei Moghadam, Adel; Tran, Ahn Thuy; Rahim, Mohammad Niaz; Ande, Sudu R; Hashemi, Mohammad; Coombs, Kevin M; Ghavami, Saeid

    2013-03-01

    Asthma is one of the fastest growing syndromes in many countries and is adding a huge cost to the health care system. Increasing reports have linked airway infectious diseases to asthma. Influenza is one of the most serious airway infectious diseases and in recent years there have been some serious influenza virus pandemics which caused increased fatality in numerous different populations. Diverse host response pathways during virus infection have been identified, including different cell death and survival pathways. These pathways include 1) programmed cell death I (apoptosis), 2) programmed cell death II (autophagy), and 3) endoplasmic reticulum stress with subsequent unfolded protein response (UPR). There has been extensive research on the regulatory roles of these pathways during the influenza virus life cycle. These studies address the benefits of enhancing or inhibiting these pathways on viral replication. Here we review the most recent and significant knowledge in this area for possible benefits to clinicians and basic scientist researchers in different areas of the respiratory and virology sciences.

  5. Asthma and influenza virus infection:focusing on cell death and stress pathways in influenza virus replication.

    Directory of Open Access Journals (Sweden)

    Behzad Yeganeh

    2013-03-01

    Full Text Available Asthma is one of the fastest growing syndromes in many countries and is adding a huge cost to the health care system. Increasing reports have linked airway infectious diseases to asthma. Influenza is one of the most serious airway infectious diseases and in recent years there have been some serious influenza virus pandemics which caused increased fatality in numerous different populations. Diverse host response pathways during virus infection have been identified, including different cell death and survival pathways. These pathways include1 programmed cell death I (apoptosis, 2 programmed cell death II (autophagy, and 3 endoplasmic reticulum stress with subsequent unfolded protein response (UPR. There has been extensive research on the regulatory roles of these pathways during the influenza virus life cycle. These studies address the benefits of enhancing or inhibiting these pathways on viral replication. Here we review the most recent and significant knowledge in this area for possible  benefits  to  clinicians and  basic  scientist researchers  in  different  areas  of  the respiratory and virology sciences.

  6. Heat stress abatement during the dry period influences prolactin signaling in lymphocytes Heat stress abatement during the dry period influences prolactin signaling in lymphocytes

    Science.gov (United States)

    Heat stress perturbs PRL release and affects dairy cow lactational performance and immune cell function. We hypothesized that greater PRL concentration in plasma of heat-stressed cows would decrease expression of PRL-R mRNA and increase mRNA expression of suppressors of cytokine signaling (SOCS) in ...

  7. Mouse hepatitis coronavirus replication induces host translational shutoff and mRNA decay, with concomitant formation of stress granules and processing bodies.

    Science.gov (United States)

    Raaben, Matthijs; Groot Koerkamp, Marian J A; Rottier, Peter J M; de Haan, Cornelis A M

    2007-09-01

    Many viruses, including coronaviruses, induce host translational shutoff, while maintaining synthesis of their own gene products. In this study we performed genome-wide microarray analyses of the expression patterns of mouse hepatitis coronavirus (MHV)-infected cells. At the time of MHV-induced host translational shutoff, downregulation of numerous mRNAs, many of which encode protein translation-related factors, was observed. This downregulation, which is reminiscent of a cellular stress response, was dependent on viral replication and caused by mRNA decay. Concomitantly, phosphorylation of the eukaryotic translation initiation factor 2alpha was increased in MHV-infected cells. In addition, stress granules and processing bodies appeared, which are sites for mRNA stalling and degradation respectively. We propose that MHV replication induces host translational shutoff by triggering an integrated stress response. However, MHV replication per se does not appear to benefit from the inhibition of host protein synthesis, at least in vitro, since viral replication was not negatively affected but rather enhanced in cells with impaired translational shutoff.

  8. p75 neurotrophin receptor signaling: mechanisms for neurotrophic modulation of cell stress?

    Science.gov (United States)

    Dobrowsky, R T; Carter, B D

    2000-08-01

    The recent recognition that the p75 neurotrophin receptor, p75((NTR)), can induce apoptotic signals has contributed to the perception that it acts primarily as a death receptor. Although the molecular mechanisms of p75(NTR) signaling remain to be fully characterized, many of the currently identified pathways activated by p75(NTR) may be generally characterized as stress response signals. This review describes recent advances in identifying the molecular components involved in p75(NTR) signal transduction and suggests that p75(NTR) signaling may more aptly serve as a general mechanism for the transduction and modulation of stress signals.

  9. Annotation and prediction of stress and workload from physiological and inertial signals.

    Science.gov (United States)

    Ghosh, Arindam; Danieli, Morena; Riccardi, Giuseppe

    2015-08-01

    Continuous daily stress and high workload can have negative effects on individuals' physical and mental well-being. It has been shown that physiological signals may support the prediction of stress and workload. However, previous research is limited by the low diversity of signals concurring to such predictive tasks and controlled experimental design. In this paper we present 1) a pipeline for continuous and real-life acquisition of physiological and inertial signals 2) a mobile agent application for on-the-go event annotation and 3) an end-to-end signal processing and classification system for stress and workload from diverse signal streams. We study physiological signals such as Galvanic Skin Response (GSR), Skin Temperature (ST), Inter Beat Interval (IBI) and Blood Volume Pulse (BVP) collected using a non-invasive wearable device; and inertial signals collected from accelerometer and gyroscope sensors. We combine them with subjects' inputs (e.g. event tagging) acquired using the agent application, and their emotion regulation scores. In our experiments we explore signal combination and selection techniques for stress and workload prediction from subjects whose signals have been recorded continuously during their daily life. The end-to-end classification system is described for feature extraction, signal artifact removal, and classification. We show that a combination of physiological, inertial and user event signals provides accurate prediction of stress for real-life users and signals.

  10. Oxidative stress and its downstream signaling in aging eyes

    Directory of Open Access Journals (Sweden)

    Pinazo-Durán MD

    2014-04-01

    Full Text Available María Dolores Pinazo-Durán,1,* Roberto Gallego-Pinazo,2,* Jose Javier García-Medina,1,3,* Vicente Zanón-Moreno,1,4 Carlo Nucci,5 Rosa Dolz-Marco,2 Sebastián Martínez-Castillo,2 Carmen Galbis-Estrada,1 Carla Marco-Ramírez,1 Maria Isabel López-Gálvez,6,* David J Galarreta,6,* Manuel Díaz-Llópis4,*1Ophthalmic Research Unit "Santiago Grisolía", Valencia, Spain; 2Department of Ophthalmology, Macula Section, The University and Polytechnic Hospital La Fe, Valencia, Spain; 3Department of Ophthalmology, University Hospital Reina Sofia, Murcia, Spain; 4Faculty of Medicine, University of Valencia, Spain; 5University of Rome Tor Vergata, Rome, Italy; 6Instituto de Oftalmobiología Aplicada (IOBA, Valladolid, Spain *Members of the Spanish Net of Ocular Pathology of the Instituto de Salud Carlos III (Madrid, OFTAREDBackground: Oxidative stress (OS and its biomarkers are the biochemical end point of the imbalance between reactive oxygen species (ROS production and the ability of the antioxidant (AOX biological systems to fight against oxidative injury.Objective: We reviewed the role of OS and its downstream signaling in aging eyes.Methods: A search of the literature and current knowledge on the physiological and pathological mechanisms of OS were revisited in relation to the eyes and the aging process. Most prevalent ocular diseases have been analyzed herein in relation to OS and nutraceutic supplements, such as dry-eye disorders, glaucoma, age-related macular degeneration, and diabetic retinopathy.Results: Clinical, biochemical, and molecular data from anterior and posterior eye segment diseases point to OS as the common pathogenic mechanism in the majority of these ocular disorders, many of which are pathologies causing visual impairment, blindness, and subsequent loss of life quality. Studies with nutraceutic supplements in aging eye-related pathologies have also been reviewed.Conclusion: OS, nutritional status, and nutraceutic supplements have

  11. DNA Damage Signaling Is Required for Replication of Human Bocavirus 1 DNA in Dividing HEK293 Cells.

    Science.gov (United States)

    Deng, Xuefeng; Xu, Peng; Zou, Wei; Shen, Weiran; Peng, Jianxin; Liu, Kaiyu; Engelhardt, John F; Yan, Ziying; Qiu, Jianming

    2017-01-01

    Human bocavirus 1 (HBoV1), an emerging human-pathogenic respiratory virus, is a member of the genus Bocaparvovirus of the Parvoviridae family. In human airway epithelium air-liquid interface (HAE-ALI) cultures, HBoV1 infection initiates a DNA damage response (DDR), activating all three phosphatidylinositol 3-kinase-related kinases (PI3KKs): ATM, ATR, and DNA-PKcs. In this context, activation of PI3KKs is a requirement for amplification of the HBoV1 genome (X. Deng, Z. Yan, F. Cheng, J. F. Engelhardt, and J. Qiu, PLoS Pathog, 12:e1005399, 2016, https://doi.org/10.1371/journal.ppat.1005399), and HBoV1 replicates only in terminally differentiated, nondividing cells. This report builds on the previous discovery that the replication of HBoV1 DNA can also occur in dividing HEK293 cells, demonstrating that such replication is likewise dependent on a DDR. Transfection of HEK293 cells with the duplex DNA genome of HBoV1 induces hallmarks of DDR, including phosphorylation of H2AX and RPA32, as well as activation of all three PI3KKs. The large viral nonstructural protein NS1 is sufficient to induce the DDR and the activation of the three PI3KKs. Pharmacological inhibition or knockdown of any one of the PI3KKs significantly decreases both the replication of HBoV1 DNA and the downstream production of progeny virions. The DDR induced by the HBoV1 NS1 protein does not cause obvious damage to cellular DNA or arrest of the cell cycle. Notably, key DNA replication factors and major DNA repair DNA polymerases (polymerase η [Pol η] and polymerase κ [Pol κ]) are recruited to the viral DNA replication centers and facilitate HBoV1 DNA replication. Our study provides the first evidence of the DDR-dependent parvovirus DNA replication that occurs in dividing cells and is independent of cell cycle arrest.

  12. New World and Old World Alphaviruses Have Evolved to Exploit Different Components of Stress Granules, FXR and G3BP Proteins, for Assembly of Viral Replication Complexes

    Science.gov (United States)

    Kim, Dal Young; Reynaud, Josephine M.; Rasalouskaya, Aliaksandra; Akhrymuk, Ivan; Mobley, James A.; Frolov, Ilya; Frolova, Elena I.

    2016-01-01

    The positive-strand RNA viruses initiate their amplification in the cell from a single genome delivered by virion. This single RNA molecule needs to become involved in replication process before it is recognized and degraded by cellular machinery. In this study, we show that distantly related New World and Old World alphaviruses have independently evolved to utilize different cellular stress granule-related proteins for assembly of complexes, which recruit viral genomic RNA and facilitate formation of viral replication complexes (vRCs). Venezuelan equine encephalitis virus (VEEV) utilizes all members of the Fragile X syndrome (FXR) family, while chikungunya and Sindbis viruses exploit both members of the G3BP family. Despite being in different families, these proteins share common characteristics, which determine their role in alphavirus replication, namely, the abilities for RNA-binding and for self-assembly into large structures. Both FXR and G3BP proteins interact with virus-specific, repeating amino acid sequences located in the C-termini of hypervariable, intrinsically disordered domains (HVDs) of viral nonstructural protein nsP3. We demonstrate that these host factors orchestrate assembly of vRCs and play key roles in RNA and virus replication. Only knockout of all of the homologs results in either pronounced or complete inhibition of replication of different alphaviruses. The use of multiple homologous proteins with redundant functions mediates highly efficient recruitment of viral RNA into the replication process. This independently evolved acquisition of different families of cellular proteins by the disordered protein fragment to support alphavirus replication suggests that other RNA viruses may utilize a similar mechanism of host factor recruitment for vRC assembly. The use of different host factors by alphavirus species may be one of the important determinants of their pathogenesis. PMID:27509095

  13. To explore relationships between physiological stress signals and stress behaviors in preterm infants during periods of exposure to environmental stress in the hospital.

    Science.gov (United States)

    Peng, Niang-Huei; Chen, Chao-Huei; Bachman, Jean; Lin, Hong-Chin; Wang, Teh-Ming; Chang, Yue-Cune; Chang, Yu-Shan

    2011-10-01

    The purpose of this exploratory descriptive study was to examine relationships among physiological stress signals (heart rate (HR), respiratory rate (RR), and oxygen saturation) and stress behaviors (6 stress behaviors related to sleep-wake states, 10 self-regulatory behaviors, and 17 behavioral stress cues) in preterm infants during periods of environmental stress. This research used a prospective repeated-measures design in a convenience sample of preterm infants of equations were used to determine relationships. Variables were measured every 2 min over 4 hr, for a total of 4,164 observations in 37 preterm infants. There were statistically significant relationships between 9 stress behavioral responses and changes in HR (seven stress behaviors and two self-regulatory behaviors; p stress behavioral responses and changes in RR (seven stress behaviors and two self-regulatory behaviors; p stress behavioral responses and changes in oxygen saturation (seven stress behaviors and four self-regulatory behaviors; p stress are related to physiological stress signals. However, results should be investigated further in larger samples.

  14. Nitric Oxide Signaling in Plant Responses to Abiotic Stresses

    Institute of Scientific and Technical Information of China (English)

    Weihua Qiao; LiuMin Fan

    2008-01-01

    Nitric oxide (NO) plays important roles in diverse physiological processes In plants. NO can provoke both beneficial and harmful effects, which depend on the concentration and location of NO in plant cells. This review is focused on NO synthesis and the functions of NO in plant responses to abiotic environmental stresses. Abiotic stresses mostly induce NO production in plants. NO alleviates the harmfulness of reactive oxygen species, and reacts with other target molecules, and regulates the expression of stress responsive genes under various stress conditions.

  15. Nonintrusive biological signal monitoring in a car to evaluate a driver's stress and health state.

    Science.gov (United States)

    Baek, Hyun Jae; Lee, Haet Bit; Kim, Jung Soo; Choi, Jong Min; Kim, Ko Keun; Park, Kwang Suk

    2009-03-01

    Nonintrusive monitoring of a driver's physiological signals was introduced and evaluated in a car as a test of extending the concept of ubiquitous healthcare to vehicles. Electrocardiogram, photoplethysmogram, galvanic skin response, and respiration were measured in the ubiquitous healthcare car (U-car) using nonintrusively installed sensors on the steering wheel, driver's seat, and seat belt. Measured signals were transmitted to the embedded computer via Bluetooth(R) communication and processed. We collected and analyzed physiological signals during driving in order to estimate a driver's stress state while using this system. In order to compare the effect of stress on physical and mental conditions, two categories of stresses were defined. Experimental results show that a driver's physiological signals were measured with acceptable quality for analysis without interrupting driving, and they were changed meaningfully due to elicited stress. This nonintrusive monitoring can be used to evaluate a driver's state of health and stress.

  16. Oxidative stress signaling to chromatin in health and disease

    KAUST Repository

    Kreuz, Sarah

    2016-06-20

    Oxidative stress has a significant impact on the development and progression of common human pathologies, including cancer, diabetes, hypertension and neurodegenerative diseases. Increasing evidence suggests that oxidative stress globally influences chromatin structure, DNA methylation, enzymatic and non-enzymatic post-translational modifications of histones and DNA-binding proteins. The effects of oxidative stress on these chromatin alterations mediate a number of cellular changes, including modulation of gene expression, cell death, cell survival and mutagenesis, which are disease-driving mechanisms in human pathologies. Targeting oxidative stress-dependent pathways is thus a promising strategy for the prevention and treatment of these diseases. We summarize recent research developments connecting oxidative stress and chromatin regulation.

  17. 53BP1 nuclear bodies form around DNA lesions generated by mitotic transmission of chromosomes under replication stress

    DEFF Research Database (Denmark)

    Lukas, Claudia; Savic, Velibor; Bekker-Jensen, Simon

    2011-01-01

    Completion of genome duplication is challenged by structural and topological barriers that impede progression of replication forks. Although this can seriously undermine genome integrity, the fate of DNA with unresolved replication intermediates is not known. Here, we show that mild replication...... bodies shield chromosomal fragile sites sequestered in these compartments against erosion. Together, these data indicate that restoration of DNA or chromatin integrity at loci prone to replication problems requires mitotic transmission to the next cell generations....... increases after genetic ablation of BLM, a DNA helicase associated with dissolution of entangled DNA. Conversely, 53BP1 nuclear bodies are partially suppressed by knocking down SMC2, a condensin subunit required for mechanical stability of mitotic chromosomes. Finally, we provide evidence that 53BP1 nuclear...

  18. Stress induced by premature chromatin condensation triggers chromosome shattering and chromothripsis at DNA sites still replicating in micronuclei or multinucleate cells when primary nuclei enter mitosis.

    Science.gov (United States)

    Terzoudi, Georgia I; Karakosta, Maria; Pantelias, Antonio; Hatzi, Vasiliki I; Karachristou, Ioanna; Pantelias, Gabriel

    2015-11-01

    Combination of next-generation DNA sequencing, single nucleotide polymorphism array analyses and bioinformatics has revealed the striking phenomenon of chromothripsis, described as complex genomic rearrangements acquired in a single catastrophic event affecting one or a few chromosomes. Via an unproven mechanism, it is postulated that mechanical stress causes chromosome shattering into small lengths of DNA, which are then randomly reassembled by DNA repair machinery. Chromothripsis is currently examined as an alternative mechanism of oncogenesis, in contrast to the present paradigm that considers a stepwise development of cancer. While evidence for the mechanism(s) underlying chromosome shattering during cancer development remains elusive, a number of hypotheses have been proposed to explain chromothripsis, including ionizing radiation, DNA replication stress, breakage-fusion-bridge cycles, micronuclei formation and premature chromosome compaction. In the present work, we provide experimental evidence on the mechanistic basis of chromothripsis and on how chromosomes can get locally shattered in a single catastrophic event. Considering the dynamic nature of chromatin nucleoprotein complex, capable of rapid unfolding, disassembling, assembling and refolding, we first show that chromatin condensation at repairing or replicating DNA sites induces the mechanical stress needed for chromosome shattering to ensue. Premature chromosome condensation is then used to visualize the dynamic nature of interphase chromatin and demonstrate that such mechanical stress and chromosome shattering can also occur in chromosomes within micronuclei or asynchronous multinucleate cells when primary nuclei enter mitosis. Following an aberrant mitosis, chromosomes could find themselves in the wrong place at the wrong time so that they may undergo massive DNA breakage and rearrangement in a single catastrophic event. Specifically, our results support the hypothesis that premature chromosome

  19. HCV Infection Induces Autocrine Interferon Signaling by Human Liver Endothelial Cell and Release of Exosomes, Which Inhibits Viral Replication

    Science.gov (United States)

    Giugliano, Silvia; Kriss, Michael; Golden-Mason, Lucy; Dobrinskikh, Evgenia; Stone, Amy E.L.; Soto-Gutierrez, Alejandro; Mitchell, Angela; Khetani, Salman R.; Yamane, Daisuke; Stoddard, Mark; Li, Hui; Shaw, George M.; Edwards, Michael G.; Lemon, Stanley M.; Gale, Michael; Shah, Vijay H.; Rosen, Hugo R.

    2014-01-01

    Background & Aims Liver sinusoidal endothelial cells (LSECs) make up a large proportion of the non-parenchymal cells in the liver. LSECs are involved in induction of immune tolerance, but little is known about their functions during hepatitis C virus (HCV) infection. Methods Primary human LSECs (HLSECs) and immortalized liver endothelial cells (TMNK-1) were exposed to various forms of HCV, including full-length transmitted/founder virus, sucrose-purified Japanese Fulminant Hepatitis-1 (JFH-1), a virus encoding a luciferase reporter, and the HCV-specific pathogen-associated molecular pattern molecules. Cells were analyzed by confocal immunofluorescence, immunohistochemical, and PCR assays. Results HLSECs internalized HCV, independent of cell–cell contacts; HCV RNA was translated but not replicated. Through pattern recognition receptors (TLR7 and retinoic acid inducible gene 1), HCV RNA induced consistent and broad transcription of multiple interferons (IFNs); supernatants from primary HLSECs transfected with HCV-specific pathogen-associated molecular pattern molecules increased induction of IFNs and IFN-stimulated genes in HLSECs. Recombinant type I and type III IFNs strongly up-regulated HLSEC transcription of interferon λ 3 (IFNL3) and viperin (RSAD2), which inhibit replication of HCV. Compared to CD8+ T cells, HLSECs suppressed HCV replication within Huh7.5.1 cells, also inducing IFN-stimulated genes in co-culture. Conditioned media from IFN-stimulated HLSECs induced expression of antiviral genes by uninfected primary human hepatocytes. Exosomes, derived from HLSECs following stimulation with either type I or type III IFNs, controlled HCV replication in a dose-dependent manner. Conclusions Cultured HLSECs produce factors that mediate immunity against HCV. HLSECs induce self-amplifying IFN-mediated responses and release of exosomes with antiviral activity. PMID:25447848

  20. FBH1 Catalyzes Regression of Stalled Replication Forks

    Directory of Open Access Journals (Sweden)

    Kasper Fugger

    2015-03-01

    Full Text Available DNA replication fork perturbation is a major challenge to the maintenance of genome integrity. It has been suggested that processing of stalled forks might involve fork regression, in which the fork reverses and the two nascent DNA strands anneal. Here, we show that FBH1 catalyzes regression of a model replication fork in vitro and promotes fork regression in vivo in response to replication perturbation. Cells respond to fork stalling by activating checkpoint responses requiring signaling through stress-activated protein kinases. Importantly, we show that FBH1, through its helicase activity, is required for early phosphorylation of ATM substrates such as CHK2 and CtIP as well as hyperphosphorylation of RPA. These phosphorylations occur prior to apparent DNA double-strand break formation. Furthermore, FBH1-dependent signaling promotes checkpoint control and preserves genome integrity. We propose a model whereby FBH1 promotes early checkpoint signaling by remodeling of stalled DNA replication forks.

  1. Plant volatiles in polluted atmospheres: stress responses and signal degradation

    National Research Council Canada - National Science Library

    BLANDE, JAMES D; HOLOPAINEN, JARMO K; NIINEMETS, ÜLO

    2014-01-01

    .... Volatiles induced by herbivore feeding are among the best studied plant responses to stress and may constitute an informative message to the surrounding community and further function in plant defence processes...

  2. Endoplasmic Reticulum Stress Signaling in Plant Immunity—At the Crossroad of Life and Death

    Directory of Open Access Journals (Sweden)

    Camilla J. Kørner

    2015-11-01

    Full Text Available Rapid and complex immune responses are induced in plants upon pathogen recognition. One form of plant defense response is a programmed burst in transcription and translation of pathogenesis-related proteins, of which many rely on ER processing. Interestingly, several ER stress marker genes are up-regulated during early stages of immune responses, suggesting that enhanced ER capacity is needed for immunity. Eukaryotic cells respond to ER stress through conserved signaling networks initiated by specific ER stress sensors tethered to the ER membrane. Depending on the nature of ER stress the cell prioritizes either survival or initiates programmed cell death (PCD. At present two plant ER stress sensors, bZIP28 and IRE1, have been described. Both sensor proteins are involved in ER stress-induced signaling, but only IRE1 has been additionally linked to immunity. A second branch of immune responses relies on PCD. In mammals, ER stress sensors are involved in activation of PCD, but it is unclear if plant ER stress sensors play a role in PCD. Nevertheless, some ER resident proteins have been linked to pathogen-induced cell death in plants. In this review, we will discuss the current understanding of plant ER stress signaling and its cross-talk with immune signaling.

  3. Regulation of Replication Recovery and Genome Integrity

    DEFF Research Database (Denmark)

    Colding, Camilla Skettrup

    Preserving genome integrity is essential for cell survival. To this end, mechanisms that supervise DNA replication and respond to replication perturbations have evolved. One such mechanism is the replication checkpoint, which responds to DNA replication stress and acts to ensure replication pausing...

  4. Damage-induced DNA replication stalling relies on MAPK-activated protein kinase 2 activity

    DEFF Research Database (Denmark)

    Köpper, Frederik; Bierwirth, Cathrin; Schön, Margarete

    2013-01-01

    DNA damage can obstruct replication forks, resulting in replicative stress. By siRNA screening, we identified kinases involved in the accumulation of phosphohistone 2AX (γH2AX) upon UV irradiation-induced replication stress. Surprisingly, the strongest reduction of phosphohistone 2AX followed...... replication impaired by gemcitabine or by Chk1 inhibition. This rescue strictly depended on translesion DNA polymerases. In conclusion, instead of being an unavoidable consequence of DNA damage, alterations of replication speed and origin firing depend on MK2-mediated signaling....... knockdown of the MAP kinase-activated protein kinase 2 (MK2), a kinase currently implicated in p38 stress signaling and G2 arrest. Depletion or inhibition of MK2 also protected cells from DNA damage-induced cell death, and mice deficient for MK2 displayed decreased apoptosis in the skin upon UV irradiation...

  5. A new approach to oxidative stress and inflammatory signaling during labour in healthy mothers and neonates

    National Research Council Canada - National Science Library

    Díaz-Castro, Javier; Florido, Jesus; Kajarabille, Naroa; Prados, Sonia; de Paco, Catalina; Ocon, Olga; Pulido-Moran, Mario; Ochoa, Julio J

    2015-01-01

    The objective of the current study was to investigate for the first time and simultaneously the oxidative stress and inflammatory signaling induced during the delivery in healthy mothers and their neonates...

  6. A New Approach to Oxidative Stress and Inflammatory Signaling during Labour in Healthy Mothers and Neonates

    National Research Council Canada - National Science Library

    Díaz-Castro, Javier; Florido, Jesus; Kajarabille, Naroa; Prados, Sonia; de Paco, Catalina; Ocon, Olga; Pulido-Moran, Mario; Ochoa, Julio J

    2015-01-01

      The objective of the current study was to investigate for the first time and simultaneously the oxidative stress and inflammatory signaling induced during the delivery in healthy mothers and their neonates...

  7. TGF-β and iron differently alter HBV replication in human hepatocytes through TGF-β/BMP signaling and cellular microRNA expression.

    Directory of Open Access Journals (Sweden)

    Sun O Park

    Full Text Available The nature of host-virus interactions in hepatitis B virus infection is incompletely understood. Since soluble factors, e.g., cytokines and metals, may exacerbate liver injury in chronic hepatitis, we considered that defining the effects of receptor-mediated signaling upon viral replication will be significant. Consequently, we studied effects of iron or TGF-β-induced TGF-β/BMP signaling in the HepG2 2.2.15 cell model of hepatitis B virus replication. We found iron and TGF-β increased hepcidin mRNA expression or TGF-β receptor kinase activity, respectively, which indicated that 2.2.15 cells responded appropriately to these substances. However, iron increased but TGF-β decreased hepatitis B virus mRNA and DNA expression. TGF-β induced expression at the mRNA level of multiple TGF-β/BMP pathway genes. This change was not observed in iron-treated cells. On the other hand, presence of SMAD proteins in iron or TGF-β-treated cells, including of SMAD4, did confirm convergence of TGF-β/BMP signaling pathways under these conditions. Since transcription factors in TGF-β/BMP signaling pathways could not have directly targeted hepatitis B virus itself, we studied whether iron or TGF-β exerted their effects through alternative mechanisms, such as by involvement of antiviral cellular microRNAs. We discovered cellular microRNA expression profiles were significantly different in iron or TGF-β-treated cells compared with untreated control cells. In many cases, exposure to iron or TGF-β changed microRNA expression in opposite directions. Introduction in cells of sequences representing such differentially expressed microRNAs, e.g., hsa-miR-125a-5p and -151-5p, even reproduced effects on virus replication of iron- or TGF-β. We surmised that TGF-β/BMP pathway members, i.e., SMADs, likely governed iron or TGF-β-induced microRNA expression. Iron may have mediated Drosha/DGCR8/heme-mediated processing of microRNAs. In turn, cellular microRNAs regulated

  8. Role of extracellular signal-regulated kinases 1 and 2 and p38 mitogen-activated protein kinase pathways in regulating replication of Penicillium marneffei in human macrophages.

    Science.gov (United States)

    Chen, Renqiong; Li, Xiqing; Lu, Sha; Ma, Tuan; Huang, Xiaowen; Mylonakis, Eleftherios; Liang, Yuheng; Xi, Liyan

    2014-05-01

    Penicillium marneffei (P. marneffei) is a human pathogen which persists in macrophages and threatens the immunocompromised patients. To elucidate the mechanisms involved, we investigated the role of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38 mitogen-activated protein kinase (p38) pathways in cytokine expression, phagosome-lysosome fusion and replication of P. marneffei in P. marneffei-infected human macrophages. Analysis of both ERK1/2 and p38 showed rapid phosphorylation in response to P. marneffei. Using specific inhibitors of p38 (SB203580) and MAP kinase kinase-1 (PD98059), we found that ERK1/2 and p38 were essential for P. marneffei-induced tumor necrosis factor-α production, whereas p38, but not that of ERK, was essential for IL-10 production. Furthermore, the presence of PD98059 always decreased phagosomal acidification and maturation and increased intracellular multiplication of P. marneffei, whereas the use of SB203580 always increased phagosomal acidification and maturation and decreased intracellular replication. These data suggest that a proper balance of between ERK1/2 and p38 may play an important role in controlling the replication of P. marneffei. Our findings further indicate a novel therapeutic avenue for treating P. marneffei by stimulating ERK1/2 or activating ERK1/2-dependent mechanisms.

  9. Role of Reactive Oxygen Species in signalling and oxidative stress

    OpenAIRE

    2015-01-01

    Results reported in this Thesis contribute to the comprehension of the complicated world of “redox biology”. ROS regulate signalling pathways both in physiological responses and in pathogenesis and progression of diseases. In cancer cells, the increase in ROS generation from metabolic abnormalities and oncogenic signalling may trigger a redox adaptation response, leading to an up-regulation of antioxidant capacity in order to maintain the ROS level below the toxic threshold. Thus, cancer c...

  10. Evaluating the Effects of Traffic on Driver Stopping and Turn Signal Use at a Stop Sign: A Systematic Replication

    Science.gov (United States)

    Lebbon, Angela R.; Austin, John; Van Houten, Ron; Malenfant, Louis E.

    2007-01-01

    The current analyses of observational data found that oncoming traffic substantially affected driver stopping patterns and turn signal use at the target stop sign. The percentage of legal stops and turn signal use by drivers in the presence and absence of traffic was analyzed using a multi-element design. The results showed that legal stops were…

  11. Tart cherry extracts reduce inflammatory and oxidative stress signaling in microglial cells

    Science.gov (United States)

    Tart cherries contain an array of polyphenols that can decrease inflammation and oxidative stress (OS), which contribute to cognitive declines seen in aging populations. Previous studies have shown that polyphenols from dark-colored fruits can reduce stress-mediated signaling in BV-2 mouse microglia...

  12. Class II integrase mutants with changes in putative nuclear localization signals are primarily blocked at a postnuclear entry step of human immunodeficiency virus type 1 replication.

    Science.gov (United States)

    Lu, Richard; Limón, Ana; Devroe, Eric; Silver, Pamela A; Cherepanov, Peter; Engelman, Alan

    2004-12-01

    Integrase has been implicated in human immunodeficiency virus type 1 (HIV-1) nuclear import. Integrase analyses, however, can be complicated by the pleiotropic nature of mutations: whereas class I mutants are integration defective, class II mutants display additional assembly and/or reverse transcription defects. We previously determined that HIV-1(V165A), originally reported as defective for nuclear import, was a class II mutant. Here we analyzed mutants containing changes in other putative nuclear localization signals, including (186)KRK(188)/(211)KELQKQITK(219) and Cys-130. Previous work established HIV-1(K186Q), HIV-1(Q214L/Q216L), and HIV-1(C130G) as replication defective, but phenotypic classification was unclear and nuclear import in nondividing cells was not addressed. Consistent with previous reports, most of the bipartite mutants studied here were replication defective. These mutants as well as HIV-1(V165A) synthesized reduced cDNA levels, but a normal fraction of mutant cDNA localized to dividing and nondividing cell nuclei. Somewhat surprisingly, recombinant class II mutant proteins were catalytically active, and class II Vpr-integrase fusion proteins efficiently complemented class I mutant virus. Since a class I Vpr-integrase mutant efficiently complemented class II mutant viruses under conditions in which class II Vpr-integrases failed to function, we conclude that classes I and II define two distinct complementation groups and suggest that class II mutants are primarily defective at a postnuclear entry step of HIV-1 replication. HIV-1(C130G) was also defective for reverse transcription, but Vpr-integrase(C130G) did not efficiently complement class I mutant HIV-1. Since HIV-1(C130A) grew like the wild type, we conclude that Cys-130 is not essential for replication and speculate that perturbation of integrase structure contributed to the pleiotropic HIV-1(C130G) phenotype.

  13. A New Insight of Salt Stress Signaling in Plant.

    Science.gov (United States)

    Park, Hee Jin; Kim, Woe-Yeon; Yun, Dae-Jin

    2016-06-30

    Many studies have been conducted to understand plant stress responses to salinity because irrigation-dependent salt accumulation compromises crop productivity and also to understand the mechanism through which some plants thrive under saline conditions. As mechanistic understanding has increased during the last decades, discovery-oriented approaches have begun to identify genetic determinants of salt tolerance. In addition to osmolytes, osmoprotectants, radical detoxification, ion transport systems, and changes in hormone levels and hormone-guided communications, the Salt Overly Sensitive (SOS) pathway has emerged to be a major defense mechanism. However, the mechanism by which the components of the SOS pathway are integrated to ultimately orchestrate plant-wide tolerance to salinity stress remains unclear. A higher-level control mechanism has recently emerged as a result of recognizing the involvement of GIGANTEA (GI), a protein involved in maintaining the plant circadian clock and control switch in flowering. The loss of GI function confers high tolerance to salt stress via its interaction with the components of the SOS pathway. The mechanism underlying this observation indicates the association between GI and the SOS pathway and thus, given the key influence of the circadian clock and the pathway on photoperiodic flowering, the association between GI and SOS can regulate growth and stress tolerance. In this review, we will analyze the components of the SOS pathways, with emphasis on the integration of components recognized as hallmarks of a halophytic lifestyle.

  14. Analysis of stress-induced duplex destabilization (SIDD properties of replication origins, genes and intergenes in the fission yeast, Schizosaccharomyces pombe

    Directory of Open Access Journals (Sweden)

    Yadav Mukesh P

    2012-11-01

    Full Text Available Abstract Background Replication and transcription, the two key functions of DNA, require unwinding of the DNA double helix. It has been shown that replication origins in the budding yeast, Saccharomyces cerevisiae contain an easily unwound stretch of DNA. We have used a recently developed method for determining the locations and degrees of stress-induced duplex destabilization (SIDD for all the reported replication origins in the genome of the fission yeast, Schizosaccharomyces pombe. Results We have found that the origins are more susceptible to SIDD as compared to the non-origin intergenic regions (NOIRs and genes. SIDD analysis of many known origins in other eukaryotes suggests that SIDD is a common property of replication origins. Interestingly, the previously shown deletion-dependent changes in the activities of the origins of the ura4 origin region on chromosome 3 are paralleled by changes in SIDD properties, suggesting SIDD’s role in origin activity. SIDD profiling following in silico deletions of some origins suggests that many of the closely spaced S. pombe origins could be clusters of two or three weak origins, similar to the ura4 origin region. Conclusion SIDD appears to be a highly conserved, functionally important property of replication origins in S. pombe and other organisms. The distinctly low SIDD scores of origins and the long range effects of genetic alterations on SIDD properties provide a unique predictive potential to the SIDD analysis. This could be used in exploring different aspects of structural and functional organization of origins including interactions between closely spaced origins.

  15. Identifying leaf traits that signal stress in TIR spectra

    Science.gov (United States)

    Buitrago Acevedo, Maria F.; Groen, Thomas A.; Hecker, Christoph A.; Skidmore, Andrew K.

    2017-03-01

    Plants under constant water and temperature stress experience a chain of reactions that in the long term alter their leaf traits (morphology, anatomy and chemistry). The use of these traits as proxies for assessing plant stress was so far mainly based on conventional laboratory methods, which are expensive and time-consuming. Remote sensing methods based on spectral changes can detect changes in pigments and productivity using the visible and near infrared. However, the use of infrared spectra, where changes in the spectra are associated with physical changes of the leaf, is still incipient. In this study plants of Rhododendron cf. catawbiense, were exposed to low temperatures and low soil water content during a six months experiment. The spectral response in the infrared region 1.4-16 μm, microstructural variables, leaf water content, leaf area and leaf molecules such as lignin and cellulose concentrations were measured in individual leaves after the period of stress. This study revealed that under cold conditions plants have most changes in leaf water content, lignin and cellulose concentrations and leaf area, while under drought conditions the most striking change is water loss. These leaf trait modifications are also correlated with changes in thermal infrared spectra, showing their potential as proxies for detecting plant stress in this species. A multinomial model allows the estimation of the stress treatments imposed on these plants from their infrared spectra. This model reveals a group of 15 bands in the SWIR and MWIR between 2.23 and 7.77 μm, which show relatively large changes, and had an overall accuracy of 87%. Finally, individual partial least squares regression models show that lignin, cellulose, leaf water content and leaf area are the leaf traits reacting significantly to long-term stress and that are also generating measurable changes in the infrared spectra. Although these models are based on laboratory data, the congruence of the identified

  16. Melusin Promotes a Protective Signal Transduction Cascade in Stressed Hearts

    Science.gov (United States)

    Sorge, Matteo; Brancaccio, Mara

    2016-01-01

    Melusin is a chaperone protein selectively expressed in heart and skeletal muscles. Melusin expression levels correlate with cardiac function in pre-clinical models and in human patients with aortic stenosis. Indeed, previous studies in several animal models indicated that Melusin plays a broad cardioprotective role in different pathological conditions. Chaperone proteins, besides playing a role in protein folding, are also able to facilitate supramolecular complex formation and conformational changes due to activation/deactivation of signaling molecules. This role sets chaperone proteins as crucial regulators of intracellular signal transduction pathways. In particular Melusin activates AKT and ERK1/2 signaling, protects cardiomyocytes from apoptosis and induces a compensatory hypertrophic response in several pathological conditions. Therefore, selective delivery of the Melusin gene in heart via cardiotropic adenoviral associated virus serotype 9 (AAV9), may represent a new promising gene-therapy approach for different cardiac pathologies. PMID:27672636

  17. Modulation of leaf conductance by root to shoot signaling under water stress in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Fan Yi-juan; Liu Qing; Wei Kai-fa; Li Bing-bing; Ren Hui-bo; Gao Zhi-hui; Jia Wen-suo

    2006-01-01

    Signal communication between root and shoot plays a crucial role in plant resistance to water stress. While many studies on root to shoot signals have been carried out in many plant species, no information is available for the model plant, Arabidopsis, whose adoption has great significance for further probing the molecular aspects of long distance stress signals. Here, we introduced the establishment of techniques for investigations of root to shoot signals in Arabidopsis. Stomatal movements in relation to root signals were probed by using these techniques. The results show that Arabidopsis is a suitable plant species for partial roots drying (PRD)experiments. In the PRD system, while no significant differences were found in leaf water potential between well-watered and stressed plants, water stress led to a decrease in leaf conductance, which suggests a regulation of stomatal movements by root to shoot signals. While water stress caused a significant increase in the concentration of sap abscisic acid (ABA) of xylem, no increase in xylem sap pH was observed. Moreover, the increase in the ABA content of xylem coincided with the decrease in leaf conductance,which suggests a possible role of ABA in the regulation of stomatal movements. Infrared temperature images showed that leaf temperatures of PRD plant were higher compared with those of well-watered plants, which further indicates that stomatal movements can be modulated by root signals. The confirmation of root to shoot signaling in Arabidopsis has established a basis for further investigation into the molecular mechanisms of the root to shoot signaling under water stress.

  18. Endothelial cell culture model for replication of physiological profiles of pressure, flow, stretch, and shear stress in vitro.

    Science.gov (United States)

    Estrada, Rosendo; Giridharan, Guruprasad A; Nguyen, Mai-Dung; Roussel, Thomas J; Shakeri, Mostafa; Parichehreh, Vahidreza; Prabhu, Sumanth D; Sethu, Palaniappan

    2011-04-15

    The phenotype and function of vascular cells in vivo are influenced by complex mechanical signals generated by pulsatile hemodynamic loading. Physiologically relevant in vitro studies of vascular cells therefore require realistic environments where in vivo mechanical loading conditions can be accurately reproduced. To accomplish a realistic in vivo-like loading environment, we designed and fabricated an Endothelial Cell Culture Model (ECCM) to generate physiological pressure, stretch, and shear stress profiles associated with normal and pathological cardiac flow states. Cells within this system were cultured on a stretchable, thin (∼500 μm) planar membrane within a rectangular flow channel and subject to constant fluid flow. Under pressure, the thin planar membrane assumed a concave shape, representing a segment of the blood vessel wall. Pulsatility was introduced using a programmable pneumatically controlled collapsible chamber. Human aortic endothelial cells (HAECs) were cultured within this system under normal conditions and compared to HAECs cultured under static and "flow only" (13 dyn/cm(2)) control conditions using microscopy. Cells cultured within the ECCM were larger than both controls and assumed an ellipsoidal shape. In contrast to static control control cells, ECCM-cultured cells exhibited alignment of cytoskeletal actin filaments and high and continuous expression levels of β-catenin indicating an in vivo-like phenotype. In conclusion, design, fabrication, testing, and validation of the ECCM for culture of ECs under realistic pressure, flow, strain, and shear loading seen in normal and pathological conditions was accomplished. The ECCM therefore is an enabling technology that allows for study of ECs under physiologically relevant biomechanical loading conditions in vitro. © 2011 American Chemical Society

  19. Oxidative Stress Promotes Peroxiredoxin Hyperoxidation and Attenuates Pro-survival Signaling in Aging Chondrocytes.

    Science.gov (United States)

    Collins, John A; Wood, Scott T; Nelson, Kimberly J; Rowe, Meredith A; Carlson, Cathy S; Chubinskaya, Susan; Poole, Leslie B; Furdui, Cristina M; Loeser, Richard F

    2016-03-25

    Oxidative stress-mediated post-translational modifications of redox-sensitive proteins are postulated as a key mechanism underlying age-related cellular dysfunction and disease progression. Peroxiredoxins (PRX) are critical intracellular antioxidants that also regulate redox signaling events. Age-related osteoarthritis is a common form of arthritis that has been associated with mitochondrial dysfunction and oxidative stress. The objective of this study was to determine the effect of aging and oxidative stress on chondrocyte intracellular signaling, with a specific focus on oxidation of cytosolic PRX2 and mitochondrial PRX3. Menadione was used as a model to induce cellular oxidative stress. Compared with chondrocytes isolated from young adult humans, chondrocytes from older adults exhibited higher levels of PRX1-3 hyperoxidation basally and under conditions of oxidative stress. Peroxiredoxin hyperoxidation was associated with inhibition of pro-survival Akt signaling and stimulation of pro-death p38 signaling. These changes were prevented in cultured human chondrocytes by adenoviral expression of catalase targeted to the mitochondria (MCAT) and in cartilage explants from MCAT transgenic mice. Peroxiredoxin hyperoxidation was observedin situin human cartilage sections from older adults and in osteoarthritic cartilage. MCAT transgenic mice exhibited less age-related osteoarthritis. These findings demonstrate that age-related oxidative stress can disrupt normal physiological signaling and contribute to osteoarthritis and suggest peroxiredoxin hyperoxidation as a potential mechanism.

  20. Stress and radiation-induced activation of multiple intracellular signaling pathways.

    Science.gov (United States)

    Dent, Paul; Yacoub, Adly; Contessa, Joseph; Caron, Ruben; Amorino, George; Valerie, Kristoffer; Hagan, Michael P; Grant, Steven; Schmidt-Ullrich, Rupert

    2003-03-01

    Exposure of cells to a variety of stresses induces compensatory activations of multiple intracellular signaling pathways. These activations can play critical roles in controlling cell survival and repopulation effects in a stress-specific and cell type-dependent manner. Some stress-induced signaling pathways are those normally activated by mitogens such as the EGFR/RAS/PI3K-MAPK pathway. Other pathways activated by stresses such as ionizing radiation include those downstream of death receptors, including pro-caspases and the transcription factor NFKB. This review will attempt to describe some of the complex network of signals induced by ionizing radiation and other cellular stresses in animal cells, with particular attention to signaling by growth factor and death receptors. This includes radiation-induced signaling via the EGFR and IGFI-R to the PI3K, MAPK, JNK, and p38 pathways as well as FAS-R and TNF-R signaling to pro-caspases and NFKB. The roles of autocrine ligands in the responses of cells and bystander cells to radiation and cellular stresses will also be discussed. Based on the data currently available, it appears that radiation can simultaneously activate multiple signaling pathways in cells. Reactive oxygen and nitrogen species may play an important role in this process by inhibiting protein tyrosine phosphatase activity. The ability of radiation to activate signaling pathways may depend on the expression of growth factor receptors, autocrine factors, RAS mutation, and PTEN expression. In other words, just because pathway X is activated by radiation in one cell type does not mean that pathway X will be activated in a different cell type. Radiation-induced signaling through growth factor receptors such as the EGFR may provide radioprotective signals through multiple downstream pathways. In some cell types, enhanced basal signaling by proto-oncogenes such as RAS may provide a radioprotective signal. In many cell types, this may be through PI3K, in others

  1. Phosphatidic acid: a multifunctional stress-signalling lipid in plants.

    NARCIS (Netherlands)

    C. Testerink; T. Munnik

    2005-01-01

    Phosphatidic acid (PA) has only recently been identified as an important signaling molecule in both plants and animals. Nonetheless, it already promises to rival the importance of the classic second messengers Ca(2+) and cAMP. In plants, its formation is triggered in response to various biotic and a

  2. Phosphoinositides and lipid kinases in oxidative stress signalling and cancer

    NARCIS (Netherlands)

    Keune, W.J.H.

    2013-01-01

    Phosphoinositides are implicated in virtually all aspects of cellular welfare. They help to maintain the structure of biomembranes, but are also essential signal transduction molecules. This is illustrated by PtdIns(4,5)P2, a versatile and important phosphoinositide that regulates many cellular proc

  3. Phosphatidic acid, a versatile water-stress signal in roots

    NARCIS (Netherlands)

    McLoughlin, F.; Testerink, C.

    2013-01-01

    Adequate water supply is of utmost importance for growth and reproduction of plants. In order to cope with water deprivation, plants have to adapt their development and metabolism to ensure survival. To maximize water use efficiency, plants use a large array of signaling mediators such as hormones,

  4. Signal transduction pathways in Synechocystis sp. PCC 6803 and biotechnological implications under abiotic stress.

    Science.gov (United States)

    Liu, Z X; Li, H C; Wei, Y P; Chu, W Y; Chong, Y L; Long, X H; Liu, Z P; Qin, S; Shao, H B

    2015-06-01

    Cyanobacteria have developed various response mechanisms in long evolution to sense and adapt to external or internal changes under abiotic stresses. The signal transduction system of a model cyanobacterium Synechocystis sp. PCC 6803 includes mainly two-component signal transduction systems of eukaryotic-type serine/threonine kinases (STKs), on which most have been investigated at present. These two-component systems play a major role in regulating cell activities in cyanobacteria. More and more co-regulation and crosstalk regulations among signal transduction systems had been discovered due to increasing experimental data, and they are of great importance in corresponding to abiotic stresses. However, mechanisms of their functions remain unknown. Nevertheless, the two signal transduction systems function as an integral network for adaption in different abiotic stresses. This review summarizes available knowledge on the signal transduction network in Synechocystis sp. PCC 6803 and biotechnological implications under various stresses, with focuses on the co-regulation and crosstalk regulations among various stress-responding signal transduction systems.

  5. Emotional stress recognition using a new fusion link between electroencephalogram and peripheral signals

    Directory of Open Access Journals (Sweden)

    Seyyed Abed Hosseini

    2015-10-01

    Full Text Available Background: This paper proposes a new emotional stress assessment system using multi-modal bio-signals. Electroencephalogram (EEG is the reflection of brain activity and is widely used in clinical diagnosis and biomedical research.Methods: We design an efficient acquisition protocol to acquire the EEG signals in five channels (FP1, FP2, T3, T4 and Pz and peripheral signals such as blood volume pulse, skin conductance (SC and respiration, under images induction (calm-neutral and negatively excited for the participants. The visual stimuli images are selected from the subset International Affective Picture System database. The qualitative and quantitative evaluation of peripheral signals are used to select suitable segments of EEG signals for improving the accuracy of signal labeling according to emotional stress states. After pre-processing, wavelet coefficients, fractal dimension, and Lempel-Ziv complexity are used to extract the features of the EEG signals. The vast number of features leads to the problem of dimensionality, which is solved using the genetic algorithm as a feature selection method.Results: The results show that the average classification accuracy is 89.6% for two categories of emotional stress states using the support vector machine (SVM.Conclusion: This is a great improvement in results compared to other similar researches. We achieve a noticeable improvement of 11.3% in accuracy using SVM classifier, in compared to previous studies. Therefore, a new fusion between EEG and peripheral signals are more robust in comparison to the separate signals.

  6. Emotional stress recognition using a new fusion link between electroencephalogram and peripheral signals.

    Science.gov (United States)

    Hosseini, Seyyed Abed; Khalilzadeh, Mohammad Ali; Naghibi-Sistani, Mohammad Bagher; Homam, Seyyed Mehran

    2015-07-06

    This paper proposes a new emotional stress assessment system using multi-modal bio-signals. Electroencephalogram (EEG) is the reflection of brain activity and is widely used in clinical diagnosis and biomedical research. We design an efficient acquisition protocol to acquire the EEG signals in five channels (FP1, FP2, T3, T4 and Pz) and peripheral signals such as blood volume pulse, skin conductance (SC) and respiration, under images induction (calm-neutral and negatively excited) for the participants. The visual stimuli images are selected from the subset International Affective Picture System database. The qualitative and quantitative evaluation of peripheral signals are used to select suitable segments of EEG signals for improving the accuracy of signal labeling according to emotional stress states. After pre-processing, wavelet coefficients, fractal dimension, and Lempel-Ziv complexity are used to extract the features of the EEG signals. The vast number of features leads to the problem of dimensionality, which is solved using the genetic algorithm as a feature selection method. The results show that the average classification accuracy is 89.6% for two categories of emotional stress states using the support vector machine (SVM). This is a great improvement in results compared to other similar researches. We achieve a noticeable improvement of 11.3% in accuracy using SVM classifier, in compared to previous studies. Therefore, a new fusion between EEG and peripheral signals are more robust in comparison to the separate signals.

  7. Relaxation phenomena of electrical signal emissions from rock following application of abrupt mechanical stress

    Directory of Open Access Journals (Sweden)

    George Hloupis

    2012-04-01

    Full Text Available

    The emission of electrical signals during application of mechanical stress to brittle geo-materials (the so-called pressure-stimulated current; PSC can provide significant information regarding the mechanical status of a studied rock sample. PSCs originate as a result of the opening of cracks and microfractures in rock. In this study, such electrical signal emissions are detected and studied when rock samples are subjected to step-wise mechanical stress, increased from low stress levels vL up to higher stress levels vH. This increase is performed at high stress rates and consequently the stress is maintained practically constant for a long period. During this time, the applied stress reaches its maximum value, and the emitted PSC decays gradually and relaxes back to a minimum value. The conducted experiments suggest that the characteristics of the relaxation processes of the PSC depend directly on the high level of the applied stress that is maintained constant after the application of each stress step. Analysis of the macroscopic parameters that characterize the relaxation phenomenon of the PSC provides clear information regarding the proximity of the applied stress to the fracture limit of the rock sample.

  8. Neuroplasticity and Calcium Signaling in Stressed Rat Amygdala

    Science.gov (United States)

    2005-02-01

    is a psychiatric disorder of considerable prevalence and morbidity and can affect persons of any age and ethnic or socioeconomic background. It is...eccentric) including paranoid, schizoid , and schizotypical disorders . Sexual abuse was most strongly associated with the presence of cluster B...Posttraumatic stress disorder (PTSD) is a syndrome of symptoms indicative of emotional dysfunction, which develop after exposure to life-threatening

  9. Global Plant Stress Signaling: Reactive Oxygen Species at the Cross-Road.

    Science.gov (United States)

    Sewelam, Nasser; Kazan, Kemal; Schenk, Peer M

    2016-01-01

    Current technologies have changed biology into a data-intensive field and significantly increased our understanding of signal transduction pathways in plants. However, global defense signaling networks in plants have not been established yet. Considering the apparent intricate nature of signaling mechanisms in plants (due to their sessile nature), studying the points at which different signaling pathways converge, rather than the branches, represents a good start to unravel global plant signaling networks. In this regard, growing evidence shows that the generation of reactive oxygen species (ROS) is one of the most common plant responses to different stresses, representing a point at which various signaling pathways come together. In this review, the complex nature of plant stress signaling networks will be discussed. An emphasis on different signaling players with a specific attention to ROS as the primary source of the signaling battery in plants will be presented. The interactions between ROS and other signaling components, e.g., calcium, redox homeostasis, membranes, G-proteins, MAPKs, plant hormones, and transcription factors will be assessed. A better understanding of the vital roles ROS are playing in plant signaling would help innovate new strategies to improve plant productivity under the circumstances of the increasing severity of environmental conditions and the high demand of food and energy worldwide.

  10. Global Plant Stress Signaling: Reactive Oxygen Species at the Cross-Road

    Science.gov (United States)

    Sewelam, Nasser; Kazan, Kemal; Schenk, Peer M.

    2016-01-01

    Current technologies have changed biology into a data-intensive field and significantly increased our understanding of signal transduction pathways in plants. However, global defense signaling networks in plants have not been established yet. Considering the apparent intricate nature of signaling mechanisms in plants (due to their sessile nature), studying the points at which different signaling pathways converge, rather than the branches, represents a good start to unravel global plant signaling networks. In this regard, growing evidence shows that the generation of reactive oxygen species (ROS) is one of the most common plant responses to different stresses, representing a point at which various signaling pathways come together. In this review, the complex nature of plant stress signaling networks will be discussed. An emphasis on different signaling players with a specific attention to ROS as the primary source of the signaling battery in plants will be presented. The interactions between ROS and other signaling components, e.g., calcium, redox homeostasis, membranes, G-proteins, MAPKs, plant hormones, and transcription factors will be assessed. A better understanding of the vital roles ROS are playing in plant signaling would help innovate new strategies to improve plant productivity under the circumstances of the increasing severity of environmental conditions and the high demand of food and energy worldwide. PMID:26941757

  11. CDIP1-BAP31 complex transduces apoptotic signals from endoplasmic reticulum to mitochondria under ER stress

    OpenAIRE

    Namba, Takushi; Tian, Fang; Chu, Kiki; Hwang, So-Young; Yoon, Kyoung Wan; Byun, Sanguine; Hiraki, Masatsugu; Mandinova, Anna; Lee, Sam W.

    2013-01-01

    Resolved ER stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a pro-apoptotic p53 target, CDIP1, acts as a key signal transducer of ER stress-mediated apoptosis. We identify BAP31, B-cell receptor-associated protein 31, as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 is required for BAP31 cl...

  12. DNA Damage Signaling Is Induced in the Absence of Epstein-Barr Virus (EBV) Lytic DNA Replication and in Response to Expression of ZEBRA.

    Science.gov (United States)

    Wang'ondu, Ruth; Teal, Stuart; Park, Richard; Heston, Lee; Delecluse, Henri; Miller, George

    2015-01-01

    Epstein Barr virus (EBV), like other oncogenic viruses, modulates the activity of cellular DNA damage responses (DDR) during its life cycle. Our aim was to characterize the role of early lytic proteins and viral lytic DNA replication in activation of DNA damage signaling during the EBV lytic cycle. Our data challenge the prevalent hypothesis that activation of DDR pathways during the EBV lytic cycle occurs solely in response to large amounts of exogenous double stranded DNA products generated during lytic viral DNA replication. In immunofluorescence or immunoblot assays, DDR activation markers, specifically phosphorylated ATM (pATM), H2AX (γH2AX), or 53BP1 (p53BP1), were induced in the presence or absence of viral DNA amplification or replication compartments during the EBV lytic cycle. In assays with an ATM inhibitor and DNA damaging reagents in Burkitt lymphoma cell lines, γH2AX induction was necessary for optimal expression of early EBV genes, but not sufficient for lytic reactivation. Studies in lytically reactivated EBV-positive cells in which early EBV proteins, BGLF4, BGLF5, or BALF2, were not expressed showed that these proteins were not necessary for DDR activation during the EBV lytic cycle. Expression of ZEBRA, a viral protein that is necessary for EBV entry into the lytic phase, induced pATM foci and γH2AX independent of other EBV gene products. ZEBRA mutants deficient in DNA binding, Z(R183E) and Z(S186E), did not induce foci of pATM. ZEBRA co-localized with HP1β, a heterochromatin associated protein involved in DNA damage signaling. We propose a model of DDR activation during the EBV lytic cycle in which ZEBRA induces ATM kinase phosphorylation, in a DNA binding dependent manner, to modulate gene expression. ATM and H2AX phosphorylation induced prior to EBV replication may be critical for creating a microenvironment of viral and cellular gene expression that enables lytic cycle progression.

  13. Effect of 25-hydroxyvitamin D3 on rotavirus replication and gene expressions of RIG-I signalling molecule in porcine rotavirus-infected IPEC-J2 cells.

    Science.gov (United States)

    Zhao, Ye; Yu, Bing; Mao, Xiangbing; He, Jun; Huang, Zhiqing; Zheng, Ping; Yu, Jie; Han, Guoquan; Liang, Xiaofang; Chen, Daiwen

    2015-01-01

    The study evaluated whether a 25-hydroxyvitamin D3 (25D3) supplementation decreases the replication of rotavirus by the retinoic acid-inducible gene I (RIG-I) signalling pathway in a porcine small intestinal epithelial cell line (IPEC-J2). The results show that IPEC-J2 cells express high baseline levels of 1α-hydroxylase (CYP27B1), which converts inactive 25D3 to the active 1,25-dihydroxyvitamin D3 (1,25D3). Porcine rotavirus (PRV) infection alone resulted in a significant increase in CYP27B1 mRNA, which augmented the production of active vitamin D. Physiological concentrations of 25D3 were found to decrease PRV replication in IPEC-J2 cells. RIG-I plays an important role in the recognition of double-stranded RNA virus by host cells. Upon recognition, RIG-I triggers a series of signalling molecules such as interferon-β (IFN-β) promoter stimulator 1 (IPS-1) leading to the expression of type I interferons (IFN-β). Active 25D3 that was generated by PRV-infected IPEC-J2 cells led to an increased expression of toll-like receptors 3 (TLR3), RIG-I, IPS-1, IFN-β and IFN-stimulated genes 15 (ISG15) with important innate immune functions. Inhibiting CYP27B1 also failed to increase RIG-I, IPS-1, IFN-β and ISG15 mRNA expression. These observations suggest that 25D3 can directly inhibit PRV in IPEC-J2 cells, which requires this active form of vitamin D. The anti-rotavirus effect of 25D3 is mediated at least in part by RIG-I signalling pathways in IPEC-J2 cells.

  14. Role and regulation of homologous recombination in response to DNA double strand breaks and replication stress in Saccharomyces cerevisiae

    OpenAIRE

    Falcettoni,

    2014-01-01

    Homologous recombination (HR) is a key pathway to maintain genomic integrity from one generation to another (meiosis) and during ontogenic development in a single organism (DNA repair). Recombination is required for the repair or tolerance of DNA damage and the recovery of stalled or broken replication forks. However, recombination is also potentially dangerous as it can lead to gross chromosomal rearrangements and potentially lethal intermediates. For this reason, recombinational events must...

  15. Stat5 signaling specifies basal versus stress erythropoietic responses through distinct binary and graded dynamic modalities.

    Directory of Open Access Journals (Sweden)

    Ermelinda Porpiglia

    2012-08-01

    Full Text Available Erythropoietin (Epo-induced Stat5 phosphorylation (p-Stat5 is essential for both basal erythropoiesis and for its acceleration during hypoxic stress. A key challenge lies in understanding how Stat5 signaling elicits distinct functions during basal and stress erythropoiesis. Here we asked whether these distinct functions might be specified by the dynamic behavior of the Stat5 signal. We used flow cytometry to analyze Stat5 phosphorylation dynamics in primary erythropoietic tissue in vivo and in vitro, identifying two signaling modalities. In later (basophilic erythroblasts, Epo stimulation triggers a low intensity but decisive, binary (digital p-Stat5 signal. In early erythroblasts the binary signal is superseded by a high-intensity graded (analog p-Stat5 response. We elucidated the biological functions of binary and graded Stat5 signaling using the EpoR-HM mice, which express a "knocked-in" EpoR mutant lacking cytoplasmic phosphotyrosines. Strikingly, EpoR-HM mice are restricted to the binary signaling mode, which rescues these mice from fatal perinatal anemia by promoting binary survival decisions in erythroblasts. However, the absence of the graded p-Stat5 response in the EpoR-HM mice prevents them from accelerating red cell production in response to stress, including a failure to upregulate the transferrin receptor, which we show is a novel stress target. We found that Stat5 protein levels decline with erythroblast differentiation, governing the transition from high-intensity graded signaling in early erythroblasts to low-intensity binary signaling in later erythroblasts. Thus, using exogenous Stat5, we converted later erythroblasts into high-intensity graded signal transducers capable of eliciting a downstream stress response. Unlike the Stat5 protein, EpoR expression in erythroblasts does not limit the Stat5 signaling response, a non-Michaelian paradigm with therapeutic implications in myeloproliferative disease. Our findings show how the

  16. Rec-8 dimorphism affects longevity, stress resistance and X-chromosome nondisjunction in C. elegans, and replicative lifespan in S. cerevisiae.

    Science.gov (United States)

    Ayyadevara, Srinivas; Tazearslan, Cagdas; Alla, Ramani; Jiang, James C; Jazwinski, S Michal; Shmookler Reis, Robert J

    2014-01-01

    A quantitative trait locus (QTL) in the nematode C. elegans, "lsq4," was recently implicated by mapping longevity genes. QTLs for lifespan and three stress-resistance traits coincided within a span of thermal stresses, and lower male frequency (reflecting X-chromosome non-disjunction), traits reversed uniquely by rec-8 knockdown. A strain bearing the longer-lived lsq4 allele, differing from the short-lived strain at resistance response mediated by innate immunity. Replicative lifespan was extended 20% in haploid S. cerevisiae (BY4741) by deletion of REC8, orthologous to nematode rec-8, implying that REC8 disruption of mitotic-cell survival is widespread, exemplifying antagonistic pleiotropy (opposing effects on lifespan vs. reproduction), and/or balancing selection wherein genomic disruption increases genetic variation under harsh conditions.

  17. Magnetic memory signals variation induced by applied magnetic field and static tensile stress in ferromagnetic steel

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Haihong, E-mail: huanghaihong@hfut.edu.cn; Yang, Cheng; Qian, Zhengchun; Han, Gang; Liu, Zhifeng

    2016-10-15

    Stress can induce a spontaneous magnetic field in ferromagnetic steel under the excitation of geomagnetic field. In order to investigate the impact of applied magnetic field and tensile stress on variation of the residual magnetic signals on the surface of ferromagnetic materials, static tensile tests of Q235 structural steel were carried out, with the normal component of the residual magnetic signals, H{sub p}(y), induced by applied magnetic fields with different intensities measured through the tensile tests. The H{sub p}(y), its slope coefficient K{sub S} and maximum gradient K{sub max} changing with the applied magnetic field H and tensile stress were observed. Results show that the magnitude of H{sub p}(y) and its slope coefficient K{sub S} increase linearly with the increase of stress in the elastic deformation stage. Under yield stress, H{sub p}(y) and K{sub S} reach its maximum, and then decrease slightly with further increase of stress. Applied magnetic field affects the magnitude of H{sub p}(y) instead of changing the signal curve′s profile; and the magnitude of H{sub p}(y), K{sub S}, K{sub max} and the change rate of K{sub S} increase with the increase of applied magnetic field. The phenomenon is also discussed from the viewpoint of magnetic charge in ferromagnetic materials. - Highlights: • We investigated how applied magnetic field and tensile stress impact H{sub p}(y) signals. • Magnitude of H{sub p}(y), K{sub S} and K{sub max} increase with the increase of applied magnetic field. • Both applied magnetic field and tensile stress impact material magnetic permeability. • Applied magnetic field can help to evaluate the stress distribution of components.

  18. ATR-p53 restricts homologous recombination in response to replicative stress but does not limit DNA interstrand crosslink repair in lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Bianca M Sirbu

    Full Text Available Homologous recombination (HR is required for the restart of collapsed DNA replication forks and error-free repair of DNA double-strand breaks (DSB. However, unscheduled or hyperactive HR may lead to genomic instability and promote cancer development. The cellular factors that restrict HR processes in mammalian cells are only beginning to be elucidated. The tumor suppressor p53 has been implicated in the suppression of HR though it has remained unclear why p53, as the guardian of the genome, would impair an error-free repair process. Here, we show for the first time that p53 downregulates foci formation of the RAD51 recombinase in response to replicative stress in H1299 lung cancer cells in a manner that is independent of its role as a transcription factor. We find that this downregulation of HR is not only completely dependent on the binding site of p53 with replication protein A but also the ATR/ATM serine 15 phosphorylation site. Genetic analysis suggests that ATR but not ATM kinase modulates p53's function in HR. The suppression of HR by p53 can be bypassed under experimental conditions that cause DSB either directly or indirectly, in line with p53's role as a guardian of the genome. As a result, transactivation-inactive p53 does not compromise the resistance of H1299 cells to the interstrand crosslinking agent mitomycin C. Altogether, our data support a model in which p53 plays an anti-recombinogenic role in the ATR-dependent mammalian replication checkpoint but does not impair a cell's ability to use HR for the removal of DSB induced by cytotoxic agents.

  19. Signaling in a polluted world: oxidative stress as an overlooked mechanism linking contaminants to animal communication

    Directory of Open Access Journals (Sweden)

    Valeria Marasco

    2016-08-01

    Full Text Available The capacity to communicate effectively with other individuals plays a critical role in the daily life of an individual and can have important fitness consequences. Animals rely on a number of visual and non-visual signals, whose production brings costs to the individual. The theory of honest signaling states that these costs are higher for low than for high-quality individuals, which prevents cheating and makes signals, such as skin and plumage colouration, indicators of individual’s quality or condition. The condition-dependent nature of signals makes them ideally suited as indicators of environmental quality, implying that signal production might be affected by contaminants. In this mini-review article, we have made the point that oxidative stress (OS is one overlooked mechanism linking exposure to contaminants to signaling because (i many contaminants can influence the individual’s oxidative balance, and (ii generation of both visual and non-visual signals is sensitive to oxidative stress. To this end, we have provided the first comprehensive review on the way both non-organic (heavy metals, especially mercury and organic (persistent organic pollutants contaminants may influence either OS or sexual signaling. We have also paid special attention to emerging classes of pollutants like brominated flame-retardants and perfluoroalkoxy alkanes in order to stimulate research in this area. We have finally provided suggestions and warnings for future work on the links among OS, sexual signaling and contaminant exposure.

  20. Salidroside Suppresses HUVECs Cell Injury Induced by Oxidative Stress through Activating the Nrf2 Signaling Pathway.

    Science.gov (United States)

    Zhu, Yao; Zhang, Ya-Jie; Liu, Wei-Wei; Shi, Ai-Wu; Gu, Ning

    2016-08-09

    Oxidative stress plays an important role in the pathogenesis of cardiovascular diseases. Salidroside (SAL), one of the main effective constituents of Rhodiola rosea, has been reported to suppress oxidative stress-induced cardiomyocyte injury and necrosis by promoting transcription of nuclear factor E2-related factor 2 (Nrf2)-regulated genes such as heme oxygenase-1 (HO-1) and NAD(P)H dehydrogenase (quinone1) (NQO1). However, it has not been indicated whether SAL might ameliorate endothelial injury induced by oxidative stress. Here, our study demonstrated that SAL might suppress HUVEC cell injury induced by oxidative stress through activating the Nrf2 signaling pathway. The results of our study indicated that SAL decreased the levels of intercellular reactive oxygen species (ROS) and malondialdehyde (MDA), and improved the activities of superoxide dismutase (SOD) and catalase (CAT), resulting in protective effects against oxidative stress-induced cell damage in HUVECs. It suppressed oxidative stress damage by inducing Nrf2 nuclear translocation and activating the expression of Nrf2-regulated antioxidant enzyme genes such as HO-1 and NQO1 in HUVECs. Knockdown of Nrf2 with siRNA abolished the cytoprotective effects against oxidative stress, decreased the expression of Nrf2, HO-1, and NQO1, and inhibited the nucleus translocation of Nrf2 in HUVECs. This study is the first to demonstrate that SAL suppresses HUVECs cell injury induced by oxidative stress through activating the Nrf2 signaling pathway.

  1. Salidroside Suppresses HUVECs Cell Injury Induced by Oxidative Stress through Activating the Nrf2 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Yao Zhu

    2016-08-01

    Full Text Available Oxidative stress plays an important role in the pathogenesis of cardiovascular diseases. Salidroside (SAL, one of the main effective constituents of Rhodiola rosea, has been reported to suppress oxidative stress-induced cardiomyocyte injury and necrosis by promoting transcription of nuclear factor E2-related factor 2 (Nrf2-regulated genes such as heme oxygenase-1 (HO-1 and NAD(PH dehydrogenase (quinone1 (NQO1. However, it has not been indicated whether SAL might ameliorate endothelial injury induced by oxidative stress. Here, our study demonstrated that SAL might suppress HUVEC cell injury induced by oxidative stress through activating the Nrf2 signaling pathway. The results of our study indicated that SAL decreased the levels of intercellular reactive oxygen species (ROS and malondialdehyde (MDA, and improved the activities of superoxide dismutase (SOD and catalase (CAT, resulting in protective effects against oxidative stress-induced cell damage in HUVECs. It suppressed oxidative stress damage by inducing Nrf2 nuclear translocation and activating the expression of Nrf2-regulated antioxidant enzyme genes such as HO-1 and NQO1 in HUVECs. Knockdown of Nrf2 with siRNA abolished the cytoprotective effects against oxidative stress, decreased the expression of Nrf2, HO-1, and NQO1, and inhibited the nucleus translocation of Nrf2 in HUVECs. This study is the first to demonstrate that SAL suppresses HUVECs cell injury induced by oxidative stress through activating the Nrf2 signaling pathway.

  2. Regulation of Replication Recovery and Genome Integrity

    DEFF Research Database (Denmark)

    Colding, Camilla Skettrup

    facilitate replication recovery after MMS-induced replication stress. Our data reveal that control of Mrc1 turnover through the interplay between posttranslational modifications and INQ localization adds another layer of regulation to the replication checkpoint. We also add replication recovery to the list...... is mediated by Mrc1, which ensures Mec1 presence at the stalled replication fork thus facilitating Rad53 phosphorylation. When replication can be resumed safely, the replication checkpoint is deactivated and replication forks restart. One mechanism for checkpoint deactivation is the ubiquitin......-targeted proteasomal degradation of Mrc1. In this study, we describe a novel nuclear structure, the intranuclear quality control compartment (INQ), which regulates protein turnover and is important for recovery after replication stress. We find that upon methyl methanesulfonate (MMS)-induced replication stress, INQ...

  3. Control of metabolic homeostasis by stress signaling is mediated by the lipocalin NLaz.

    Directory of Open Access Journals (Sweden)

    Julie Hull-Thompson

    2009-04-01

    Full Text Available Metabolic homeostasis in metazoans is regulated by endocrine control of insulin/IGF signaling (IIS activity. Stress and inflammatory signaling pathways--such as Jun-N-terminal Kinase (JNK signaling--repress IIS, curtailing anabolic processes to promote stress tolerance and extend lifespan. While this interaction constitutes an adaptive response that allows managing energy resources under stress conditions, excessive JNK activity in adipose tissue of vertebrates has been found to cause insulin resistance, promoting type II diabetes. Thus, the interaction between JNK and IIS has to be tightly regulated to ensure proper metabolic adaptation to environmental challenges. Here, we identify a new regulatory mechanism by which JNK influences metabolism systemically. We show that JNK signaling is required for metabolic homeostasis in flies and that this function is mediated by the Drosophila Lipocalin family member Neural Lazarillo (NLaz, a homologue of vertebrate Apolipoprotein D (ApoD and Retinol Binding Protein 4 (RBP4. Lipocalins are emerging as central regulators of peripheral insulin sensitivity and have been implicated in metabolic diseases. NLaz is transcriptionally regulated by JNK signaling and is required for JNK-mediated stress and starvation tolerance. Loss of NLaz function reduces stress resistance and lifespan, while its over-expression represses growth, promotes stress tolerance and extends lifespan--phenotypes that are consistent with reduced IIS activity. Accordingly, we find that NLaz represses IIS activity in larvae and adult flies. Our results show that JNK-NLaz signaling antagonizes IIS and is critical for metabolic adaptation of the organism to environmental challenges. The JNK pathway and Lipocalins are structurally and functionally conserved, suggesting that similar interactions represent an evolutionarily conserved system for the control of metabolic homeostasis.

  4. Control of metabolic homeostasis by stress signaling is mediated by the lipocalin NLaz.

    Science.gov (United States)

    Hull-Thompson, Julie; Muffat, Julien; Sanchez, Diego; Walker, David W; Benzer, Seymour; Ganfornina, Maria D; Jasper, Heinrich

    2009-04-01

    Metabolic homeostasis in metazoans is regulated by endocrine control of insulin/IGF signaling (IIS) activity. Stress and inflammatory signaling pathways--such as Jun-N-terminal Kinase (JNK) signaling--repress IIS, curtailing anabolic processes to promote stress tolerance and extend lifespan. While this interaction constitutes an adaptive response that allows managing energy resources under stress conditions, excessive JNK activity in adipose tissue of vertebrates has been found to cause insulin resistance, promoting type II diabetes. Thus, the interaction between JNK and IIS has to be tightly regulated to ensure proper metabolic adaptation to environmental challenges. Here, we identify a new regulatory mechanism by which JNK influences metabolism systemically. We show that JNK signaling is required for metabolic homeostasis in flies and that this function is mediated by the Drosophila Lipocalin family member Neural Lazarillo (NLaz), a homologue of vertebrate Apolipoprotein D (ApoD) and Retinol Binding Protein 4 (RBP4). Lipocalins are emerging as central regulators of peripheral insulin sensitivity and have been implicated in metabolic diseases. NLaz is transcriptionally regulated by JNK signaling and is required for JNK-mediated stress and starvation tolerance. Loss of NLaz function reduces stress resistance and lifespan, while its over-expression represses growth, promotes stress tolerance and extends lifespan--phenotypes that are consistent with reduced IIS activity. Accordingly, we find that NLaz represses IIS activity in larvae and adult flies. Our results show that JNK-NLaz signaling antagonizes IIS and is critical for metabolic adaptation of the organism to environmental challenges. The JNK pathway and Lipocalins are structurally and functionally conserved, suggesting that similar interactions represent an evolutionarily conserved system for the control of metabolic homeostasis.

  5. Tart Cherry Extracts Reduce Inflammatory and Oxidative Stress Signaling in Microglial Cells

    OpenAIRE

    Shukitt-Hale, Barbara; Megan E. Kelly; Donna F. Bielinski; Fisher, Derek R.

    2016-01-01

    Tart cherries contain an array of polyphenols that can decrease inflammation and oxidative stress (OS), which contribute to cognitive declines seen in aging populations. Previous studies have shown that polyphenols from dark-colored fruits can reduce stress-mediated signaling in BV-2 mouse microglial cells, leading to decreases in nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression. Thus, the present study sought to determine if tart cherries—which improved cogn...

  6. Disruption of insulin signalling affects the neuroendocrine stress reaction in Drosophila females.

    Science.gov (United States)

    Rauschenbach, Inga Y; Karpova, Evgenia K; Adonyeva, Natalya V; Andreenkova, Olga V; Faddeeva, Natalya V; Burdina, Elena V; Alekseev, Alexander A; Menshanov, Petr N; Gruntenko, Nataly E

    2014-10-15

    Juvenile hormone (JH) and dopamine are involved in the stress response in insects. The insulin/insulin-like growth factor signalling pathway has also recently been found to be involved in the regulation of various processes, including stress tolerance. However, the relationships between the JH, dopamine and insulin signalling pathways remain unclear. Here, we study the role of insulin signalling in the regulation of JH and dopamine metabolism under normal and heat stress conditions in Drosophila melanogaster females. We show that suppression of the insulin-like receptor (InR) in the corpus allatum, a specialised endocrine gland that synthesises JH, causes an increase in dopamine level and JH-hydrolysing activity and alters the activities of enzymes that produce as well as those that degrade dopamine [alkaline phosphatase (ALP), tyrosine hydroxylase (TH) and dopamine-dependent arylalkylamine N-acetyltransferase (DAT)]. We also found that InR suppression in the corpus allatum modulates dopamine, ALP, TH and JH-hydrolysing activity in response to heat stress and that it decreases the fecundity of the flies. JH application restores dopamine metabolism and fecundity in females with decreased InR expression in the corpus allatum. Our data provide evidence that the insulin/insulin-like growth factor signalling pathway regulates dopamine metabolism in females of D. melanogaster via the system of JH metabolism and that it affects the development of the neuroendocrine stress reaction and interacts with JH in the control of reproduction in this species.

  7. Vital analysis: annotating sensed physiological signals with the stress levels of first responders in action.

    Science.gov (United States)

    Gomes, P; Kaiseler, M; Queirós, C; Oliveira, M; Lopes, B; Coimbra, M

    2012-01-01

    First responders such as firefighters are exposed to extreme stress and fatigue situations during their work routines. It is thus desirable to monitor their health using wearable sensing but this is a complex and still unsolved research challenge that requires large amounts of properly annotated physiological signals data. In this paper we show that the information gathered by our Vital Analysis Framework can support the annotation of these vital signals with the stress levels perceived by the target user, confirmed by the analysis of more than 4600 hours of data collected from real firefighters in action, including 717 answers to event questionnaires from a total of 454 different events.

  8. The response to inositol: regulation of glycerolipid metabolism and stress response signaling in yeast.

    Science.gov (United States)

    Henry, Susan A; Gaspar, Maria L; Jesch, Stephen A

    2014-05-01

    This article focuses on discoveries of the mechanisms governing the regulation of glycerolipid metabolism and stress response signaling in response to the phospholipid precursor, inositol. The regulation of glycerolipid lipid metabolism in yeast in response to inositol is highly complex, but increasingly well understood, and the roles of individual lipids in stress response are also increasingly well characterized. Discoveries that have emerged over several decades of genetic, molecular and biochemical analyses of metabolic, regulatory and signaling responses of yeast cells, both mutant and wild type, to the availability of the phospholipid precursor, inositol are discussed.

  9. Neuroendocrine control of the gut during stress: corticotropin-releasing factor signaling pathways in the spotlight.

    Science.gov (United States)

    Stengel, Andreas; Taché, Yvette

    2009-01-01

    Stress affects the gastrointestinal tract as part of the visceral response. Various stressors induce similar profiles of gut motor function alterations, including inhibition of gastric emptying, stimulation of colonic propulsive motility, and hypersensitivity to colorectal distension. In recent years, substantial progress has been made in our understanding of the underlying mechanisms of stress's impact on gut function. Activation of corticotropin-releasing factor (CRF) signaling pathways mediates both the inhibition of upper gastrointestinal (GI) and the stimulation of lower GI motor function through interaction with different CRF receptor subtypes. Here, we review how various stressors affect the gut, with special emphasis on the central and peripheral CRF signaling systems.

  10. FLIP switches Fas-mediated glucose signaling in human pancreatic β cells from apoptosis to cell replication

    Science.gov (United States)

    Maedler, Kathrin; Fontana, Adriano; Ris, Frédéric; Sergeev, Pavel; Toso, Christian; Oberholzer, José; Lehmann, Roger; Bachmann, Felix; Tasinato, Andrea; Spinas, Giatgen A.; Halban, Philippe A.; Donath, Marc Y.

    2002-01-01

    Type 2 diabetes mellitus results from an inadequate adaptation of the functional pancreatic β cell mass in the face of insulin resistance. Changes in the concentration of glucose play an essential role in the regulation of β cell turnover. In human islets, elevated glucose concentrations impair β cell proliferation and induce β cell apoptosis via up-regulation of the Fas receptor. Recently, it has been shown that the caspase-8 inhibitor FLIP may divert Fas-mediated death signals into those for cell proliferation in lymphatic cells. We observed expression of FLIP in human pancreatic β cells of nondiabetic individuals, which was decreased in tissue sections of type 2 diabetic patients. In vitro exposure of islets from nondiabetic organ donors to high glucose levels decreased FLIP expression and increased the percentage of apoptotic terminal deoxynucleotidyltransferase-mediated UTP end labeling (TUNEL)-positive β cells; FLIP was no longer detectable in such TUNEL-positive β cells. Up-regulation of FLIP, by incubation with transforming growth factor β or by transfection with an expression vector coding for FLIP, protected β cells from glucose-induced apoptosis, restored β cell proliferation, and improved β cell function. The beneficial effects of FLIP overexpression were blocked by an antagonistic anti-Fas antibody, indicating their dependence on Fas receptor activation. The present data provide evidence for expression of FLIP in the human β cell and suggest a novel approach to prevent and treat diabetes by switching Fas signaling from apoptosis to proliferation. PMID:12060768

  11. Ubiquitin-dependent recruitment of the Bloom syndrome helicase upon replication stress is required to suppress homologous recombination.

    Science.gov (United States)

    Tikoo, Shweta; Madhavan, Vinoth; Hussain, Mansoor; Miller, Edward S; Arora, Prateek; Zlatanou, Anastasia; Modi, Priyanka; Townsend, Kelly; Stewart, Grant S; Sengupta, Sagar

    2013-06-12

    Limiting the levels of homologous recombination (HR) that occur at sites of DNA damage is a major role of BLM helicase. However, very little is known about the mechanisms dictating its relocalization to these sites. Here, we demonstrate that the ubiquitin/SUMO-dependent DNA damage response (UbS-DDR), controlled by the E3 ligases RNF8/RNF168, triggers BLM recruitment to sites of replication fork stalling via ubiquitylation in the N-terminal region of BLM and subsequent BLM binding to the ubiquitin-interacting motifs of RAP80. Furthermore, we show that this mechanism of BLM relocalization is essential for BLM's ability to suppress excessive/uncontrolled HR at stalled replication forks. Unexpectedly, we also uncovered a requirement for RNF8-dependent ubiquitylation of BLM and PML for maintaining the integrity of PML-associated nuclear bodies and as a consequence the localization of BLM to these structures. Lastly, we identified a novel role for RAP80 in preventing proteasomal degradation of BLM in unstressed cells. Taken together, these data highlight an important biochemical link between the UbS-DDR and BLM-dependent pathways involved in maintaining genome stability.

  12. On Time Domain Analysis of Photoplethysmogram Signals for Monitoring Heat Stress

    Directory of Open Access Journals (Sweden)

    Mohamed Elgendi

    2015-09-01

    Full Text Available There are a limited number of studies on heat stress dynamics during exercise using the photoplethysmogram (PPG and its second derivative (APG. However, we investigate the most suitable index from short PPG signal recordings for heat stress assessment. The APG waveform consists of a, b, c and d waves in systole and an e wave in diastole. Our preliminary results indicate that the use of the energy of aa area, derived from PPG signals measured from emergency responders in tropical conditions, is promising in determining the heat stress level using 20-s recordings. After examining 14 time domain features using leave-one-out cross-validation, we found that the aa energy extracted from PPG signals is the most informative feature for classifying heat-stressed subjects, with an overall accuracy of 79%. Moreover, the combination of the aa energy with the traditional heart rate variability index of heat stress (i.e., the square root of the mean of the squares of the successive aa intervals improved the heat stress detection to an overall accuracy of 83%.

  13. The effect of psychological stress and expectation on auditory perception: A signal detection analysis.

    Science.gov (United States)

    Hoskin, Robert; Hunter, Mike D; Woodruff, Peter W R

    2014-11-01

    Both psychological stress and predictive signals relating to expected sensory input are believed to influence perception, an influence which, when disrupted, may contribute to the generation of auditory hallucinations. The effect of stress and semantic expectation on auditory perception was therefore examined in healthy participants using an auditory signal detection task requiring the detection of speech from within white noise. Trait anxiety was found to predict the extent to which stress influenced response bias, resulting in more anxious participants adopting a more liberal criterion, and therefore experiencing more false positives, when under stress. While semantic expectation was found to increase sensitivity, its presence also generated a shift in response bias towards reporting a signal, suggesting that the erroneous perception of speech became more likely. These findings provide a potential cognitive mechanism that may explain the impact of stress on hallucination-proneness, by suggesting that stress has the tendency to alter response bias in highly anxious individuals. These results also provide support for the idea that top-down processes such as those relating to semantic expectation may contribute to the generation of auditory hallucinations.

  14. Magnetic memory signals variation induced by applied magnetic field and static tensile stress in ferromagnetic steel

    Science.gov (United States)

    Huang, Haihong; Yang, Cheng; Qian, Zhengchun; Han, Gang; Liu, Zhifeng

    2016-10-01

    Stress can induce a spontaneous magnetic field in ferromagnetic steel under the excitation of geomagnetic field. In order to investigate the impact of applied magnetic field and tensile stress on variation of the residual magnetic signals on the surface of ferromagnetic materials, static tensile tests of Q235 structural steel were carried out, with the normal component of the residual magnetic signals, Hp(y), induced by applied magnetic fields with different intensities measured through the tensile tests. The Hp(y), its slope coefficient KS and maximum gradient Kmax changing with the applied magnetic field H and tensile stress were observed. Results show that the magnitude of Hp(y) and its slope coefficient KS increase linearly with the increase of stress in the elastic deformation stage. Under yield stress, Hp(y) and KS reach its maximum, and then decrease slightly with further increase of stress. Applied magnetic field affects the magnitude of Hp(y) instead of changing the signal curve‧s profile; and the magnitude of Hp(y), KS, Kmax and the change rate of KS increase with the increase of applied magnetic field. The phenomenon is also discussed from the viewpoint of magnetic charge in ferromagnetic materials.

  15. Cytosolic calcium and pH signaling in plants under salinity stress.

    Science.gov (United States)

    Kader, Md Abdul; Lindberg, Sylvia

    2010-03-01

    Calcium is one of the essential nutrients for growth and development of plants. It is an important component of various structures in cell wall and membranes. Besides some fundamental roles under normal condition, calcium functions as a major secondary-messenger molecule in plants under different developmental cues and various stress conditions including salinity stress. Also changes in cytosolic pH, pH(cyt), either individually, or in coordination with changes in cytosolic Ca(2+) concentration, [Ca(2+)](cyt), evoke a wide range of cellular functions in plants including signal transduction in plant-defense responses against stresses. It is believed that salinity stress, like other stresses, is perceived at cell membrane, either extra cellular or intracellular, which then triggers an intracellular-signaling cascade including the generation of secondary messenger molecules like Ca(2+) and protons. The variety and complexity of Ca(2+) and pH signaling result from the nature of the stresses as well as the tolerance level of the plant species against that specific stress. The nature of changes in [Ca(2+)](cyt) concentration, in terms of amplitude, frequency and duration, is likely very important for decoding the specific downstream responses for salinity stress tolerance in planta. It has been observed that the signatures of [Ca(2+)](cyt) and pH differ in various studies reported so far depending on the techniques used to measure them, and also depending on the plant organs where they are measured, such as root, shoot tissues or cells. This review describes the recent advances about the changes in [Ca(2+)](cyt) and pH(cyt) at both cellular and whole-plant levels under salinity stress condition, and in various salinity-tolerant and -sensitive plant species.

  16. Impaired microglia fractalkine signaling affects stress reaction and coping style in mice.

    Science.gov (United States)

    Winkler, Zsuzsanna; Kuti, Dániel; Ferenczi, Szilamér; Gulyás, Krisztina; Polyák, Ágnes; Kovács, Krisztina J

    2017-09-15

    Microglia, resident immune cells of the CNS are sensitive to various perturbations of the environment, such as stress exposure, and may be involved in translating these changes to behavior. Among the pathways mediating stress-related neuronal cues to microglia, the fractalkine-fractalkine receptor (CX3CR1) signaling plays a crucial role. Using mice, in which the CX3CR1 gene was deleted, we explored hormonal and behavioral responses to acute and chronic stress along with changes in hypothalamic microglia. CX3CR1(-/-) animals display active escape in forced swim- and tail suspension tests, exaggerated neuronal activation in the hypothalamic paraventricular nucleus and increased corticosterone release in response to restraint. Analysis of Iba1 immunostaining of hypothalamic sections revealed stress-related reduction of microglia in CX3CR1(-/-) mice. Because microglia also contribute to energy balance regulation, we characterized metabolic phenotype of CX3CR1(-/-) mice. Comparison of respiratory exchange ratio did not show genotype effect on fuel preference, however, the energy expenditure was increased in CX3CR1(-/-) mice, which may be related to their active coping behavior. Microglia and fractalkine signaling has been repeatedly shown to be involved chronic stress-induced depressive state. CX3CR1(-/-) mice did not become anhedonic in the "two hit" chronic stress paradigm, confirming resistance of these animals to chronic stress-induced mood alterations. However, there was no difference in stress hormone levels, open field performance and hypothalamic microglia distribution between the genotypes. These results highlight differential involvement of microglia fractalkine signaling in controlling/integrating hormonal-, metabolic and behavioral responses to acute and chronic stress challenges. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Hippocampal signaling pathways are involved in stress-induced impairment of memory formation in rats.

    Science.gov (United States)

    Sardari, Maryam; Rezayof, Ameneh; Khodagholi, Fariba

    2015-11-02

    Stress is a potent modulator of hippocampal-dependent memory formation. The aim of the present study was to assess the role of hippocampal signaling pathways in stress-induced memory impairment in male Wistar rats. The animals were exposed to acute elevated platform (EP) stress and memory formation was measured by a step-through type passive avoidance task. The results indicated that post-training or pre-test exposure to EP stress impaired memory consolidation or retrieval respectively. Using western blot analysis, it was found that memory retrieval was associated with the increase in the levels of phosphorylated cAMP-responsive element binding protein (P-CREB), peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) and its downstream targets in the hippocampus. In contrast, the stress exposure decreased the hippocampal levels of these proteins. In addition, stress-induced impairment of memory consolidation or retrieval was associated with the decrease in the P-CREB/CREB ratio and the PGC-1α level in the hippocampus. On the other hand, the hippocampal level of nuclear factor E2-related factor 2 (Nrf2) and gamma-glutamylcysteine synthetase (γ-GCS) which are the master regulators of defense system were decreased by the stress exposure. The increased hippocampal levels of Nrf2 and it׳s downstream was observed during memory retrieval, while stress-induced impairment of memory consolidation or retrieval inhibited this hippocampal signaling pathway. Overall, these findings suggest that down-regulation of CREB/PGC-1α signaling cascade and Nrf2 antioxidant pathways in the hippocampus may be associated with memory impairment induced by stress. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Genome-wide transcriptome analysis reveals that cadmium stress signaling controls the expression of genes in drought stress signal pathways in rice.

    Directory of Open Access Journals (Sweden)

    Youko Oono

    Full Text Available Plant growth is severely affected by toxic concentrations of the non-essential heavy metal cadmium (Cd. Comprehensive transcriptome analysis by RNA-Seq following cadmium exposure is required to further understand plant responses to Cd and facilitate future systems-based analyses of the underlying regulatory networks. In this study, rice plants were hydroponically treated with 50 µM Cd for 24 hours and ∼60,000 expressed transcripts, including transcripts that could not be characterized by microarray-based approaches, were evaluated. Upregulation of various ROS-scavenging enzymes, chelators and metal transporters demonstrated the appropriate expression profiles to Cd exposure. Gene Ontology enrichment analysis of the responsive transcripts indicated the upregulation of many drought stress-related genes under Cd exposure. Further investigation into the expression of drought stress marker genes such as DREB suggested that expression of genes in several drought stress signal pathways was activated under Cd exposure. Furthermore, qRT-PCR analyses of randomly selected Cd-responsive metal transporter transcripts under various metal ion stresses suggested that the expression of Cd-responsive transcripts might be easily affected by other ions. Our transcriptome analysis demonstrated a new transcriptional network linking Cd and drought stresses in rice. Considering our data and that Cd is a non-essential metal, the network underlying Cd stress responses and tolerance, which plants have developed to adapt to other stresses, could help to acclimate to Cd exposure. Our examination of this transcriptional network provides useful information for further studies of the molecular mechanisms of plant adaptation to Cd exposure and the improvement of tolerance in crop species.

  19. Pre-mRNA splicing repression triggers abiotic stress signaling in plants

    KAUST Repository

    Ling, Yu

    2016-09-24

    Alternative splicing (AS) of precursor RNAs enhances transcriptome plasticity and proteome diversity in response to diverse growth and stress cues. Recent work has shown that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various inhibitors of AS. Here, we show that the macrolide pladienolide B (PB) inhibits constitutive splicing and AS in plants. Also, our RNA sequencing (RNA-seq) data revealed that PB mimics abiotic stress signals including salt, drought and abscisic acid (ABA). PB activates the abiotic stress- and ABA-responsive reporters RD29A

  20. EARLY RESPONSIVE to DEHYDRATION 15, a new transcription factor that integrates stress signaling pathways.

    Science.gov (United States)

    Alves, Murilo S; Fontes, Elizabeth P B; Fietto, Luciano G

    2011-12-01

    The Early Responsive to Dehydration (ERD) genes are defined as those genes that are rapidly activated during drought stress. The encoded proteins show a great structural and functional diversity, with a particular class of proteins acting as connectors of stress response pathways. Recent studies have shown that ERD15 proteins from different species of plants operate in cross-talk among different response pathways. In this mini-review, we show the recent progress on the functional role of this diverse family of proteins and demonstrate that a soybean ERD15 homolog can act as a connector in stress response pathways that trigger a programmed cell death signal.

  1. Activation of Brain Somatostatin Signaling Suppresses CRF Receptor-Mediated Stress Response

    Directory of Open Access Journals (Sweden)

    Andreas Stengel

    2017-04-01

    Full Text Available Corticotropin-releasing factor (CRF is the hallmark brain peptide triggering the response to stress and mediates—in addition to the stimulation of the hypothalamus-pituitary-adrenal (HPA axis—other hormonal, behavioral, autonomic and visceral components. Earlier reports indicate that somatostatin-28 injected intracerebroventricularly counteracts the acute stress-induced ACTH and catecholamine release. Mounting evidence now supports that activation of brain somatostatin signaling exerts a broader anti-stress effect by blunting the endocrine, autonomic, behavioral (with a focus on food intake and visceral gastrointestinal motor responses through the involvement of distinct somatostatin receptor subtypes.

  2. Methylglyoxal: An Emerging Signaling Molecule in Plant Abiotic Stress Responses and Tolerance

    Science.gov (United States)

    Hoque, Tahsina S.; Hossain, Mohammad A.; Mostofa, Mohammad G.; Burritt, David J.; Fujita, Masayuki; Tran, Lam-Son P.

    2016-01-01

    The oxygenated short aldehyde methylglyoxal (MG) is produced in plants as a by-product of a number of metabolic reactions, including elimination of phosphate groups from glycolysis intermediates dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. MG is mostly detoxified by the combined actions of the enzymes glyoxalase I and glyoxalase II that together with glutathione make up the glyoxalase system. Under normal growth conditions, basal levels of MG remain low in plants; however, when plants are exposed to abiotic stress, MG can accumulate to much higher levels. Stress-induced MG functions as a toxic molecule, inhibiting different developmental processes, including seed germination, photosynthesis and root growth, whereas MG, at low levels, acts as an important signaling molecule, involved in regulating diverse events, such as cell proliferation and survival, control of the redox status of cells, and many other aspects of general metabolism and cellular homeostases. MG can modulate plant stress responses by regulating stomatal opening and closure, the production of reactive oxygen species, cytosolic calcium ion concentrations, the activation of inward rectifying potassium channels and the expression of many stress-responsive genes. MG appears to play important roles in signal transduction by transmitting and amplifying cellular signals and functions that promote adaptation of plants growing under adverse environmental conditions. Thus, MG is now considered as a potential biochemical marker for plant abiotic stress tolerance, and is receiving considerable attention by the scientific community. In this review, we will summarize recent findings regarding MG metabolism in plants under abiotic stress, and evaluate the concept of MG signaling. In addition, we will demonstrate the importance of giving consideration to MG metabolism and the glyoxalase system, when investigating plant adaptation and responses to various environmental stresses. PMID:27679640

  3. The Role of MAPK Modules and ABA during Abiotic Stress Signaling

    KAUST Repository

    Zélicourt, Axel de

    2016-05-01

    To respond to abiotic stresses, plants have developed specific mechanisms that allow them to rapidly perceive and respond to environmental changes. The phytohormone abscisic acid (ABA) was shown to be a pivotal regulator of abiotic stress responses in plants, triggering major changes in plant physiology. The ABA core signaling pathway largely relies on the activation of SnRK2 kinases to mediate several rapid responses, including gene regulation, stomatal closure, and plant growth modulation. Mitogen-activated protein kinases (MAPKs) have also been implicated in ABA signaling, but an entire ABA-activated MAPK module was uncovered only recently. In this review, we discuss the evidence for a role of MAPK modules in the context of different plant ABA signaling pathways. Abiotic stresses impact average yield in agriculture by more than 50% globally.Since ABA is a key regulator of abiotic stress responses, an understanding of its functioning at the molecular level is essential for plant breeding. Although the ABA core signaling pathway has been unraveled, several downstream events are still unclear.MAPKs are involved in most plant developmental stages and in response to stresses. Several members of the MAPK family were shown to be directly or indirectly activated by the ABA core signaling pathway.Recent evidence shows that the complete MAP3K17/18-MKK3-MPK1/2/7/14 module is under the control of ABA, whose members are under the transcriptional and post-translational control of the ABA core signaling pathway. © 2016 Elsevier Ltd.

  4. Insulin Signaling in the Aging of Healthy and Proteotoxically Stressed Mechanosensory Neurons

    Directory of Open Access Journals (Sweden)

    Courtney eScerbak

    2014-07-01

    Full Text Available Insulin signaling is central to cellular metabolism and organismal aging. However, the role of insulin signaling in natural and proteotoxically stressed aging neurons has yet to be fully described. We studied aging of Caenorbaditis elegans mechanosensory neurons expressing a neurotoxic expanded polyglutamine transgene (polyQ128, or lacking this proteotoxicity stressor (polyQ0, under conditions in which the insulin signaling pathway was disrupted by RNA interference (RNAi. We describe specific changes in lifespan, mechanosensory neuronal morphologies, and mechansensory function following RNAi treatment targeting the insulin signaling pathway. Overall, we confirmed that transcription factor DAF-16 is neuroprotective in the proteotoxically stressed model, though not strikingly in the naturally aging model. Decreased insulin signaling through daf-2 RNAi improved mechanosensory function in both models and decreased protein aggregation load in polyQ128, yet showed opposing effects on accumulation of neuronal aberrations in both strains. Decreased daf-2 signaling slightly enhanced mechanosensation while greatly enhancing branching of the mechanosensory neuron axons and dendrites in polyQ0 animals, suggesting that branching is an adaptive response in natural aging. These effects in polyQ0 did not appear to involve DAF-16, suggesting the existence of a non-canonical DAF-2 pathway for the modulation of morphological adaptation. However, in polyQ128 animals, decreased daf-2 signaling significantly enhanced mechanosensation while decreasing neuronal aberrations. Unlike other interventions that reduce the strength of insulin signaling, daf-2 RNAi dramatically redistributed large polyQ128 aggregates to the cell body, away from neuronal processes. Our results suggest that insulin signaling strength can differentially affect specific neurons aging naturally or under proteotoxic stress.

  5. SETD2 loss-of-function promotes renal cancer branched evolution through replication stress and impaired DNA repair

    DEFF Research Database (Denmark)

    Kanu, N.; Grönroos, E.; Martinez, P.

    2015-01-01

    Defining mechanisms that generate intratumour heterogeneity and branched evolution may inspire novel therapeutic approaches to limit tumour diversity and adaptation. SETD2 (Su(var), Enhancer of zeste, Trithorax-domain containing 2) trimethylates histone-3 lysine-36 (H3K36me3) at sites of active...... proteins minichromosome maintenance complex component (MCM7) and DNA polymerase δ hindering replication fork progression, and failure to load lens epithelium-derived growth factor and the Rad51 homologous recombination repair factor at DNA breaks. Consistent with these data, we observe chromosomal...... breakpoint locations are biased away from H3K36me3 sites in SETD2 wild-type ccRCCs relative to tumours with bi-allelic SETD2 aberrations and that H3K36me3-negative ccRCCs display elevated DNA damage in vivo. These data suggest a role for SETD2 in maintaining genome integrity through nucleosome stabilization...

  6. An epigenome-wide association meta-analysis of prenatal maternal stress in neonates: A model approach for replication

    NARCIS (Netherlands)

    J. Rijlaarsdam (Jolien); I. Pappa (Irene); E. Walton (Esther); M.J. Bakermans-Kranenburg (Marian); V. Mileva-Seitz; R.C.A. Rippe (Ralph C.A.); S.J. Roza (Sabine); V.W.V. Jaddoe (Vincent); F.C. Verhulst (Frank); J.F. Felix (Janine); C.A.M. Cecil (Charlotte A.M.); C.L. Relton (Caroline); T.R. Gaunt (Tom); W.L. McArdle (Wendy); J. Mill (Jonathan); E.D. Barker (Edward D.); H.W. Tiemeier (Henning); M.H. van IJzendoorn (Marinus)

    2016-01-01

    textabstractABSTRACT: Prenatal maternal stress exposure has been associated with neonatal differential DNA methylation. However, the available evidence in humans is largely based on candidate gene methylation studies, where only a few CpG sites were evaluated. The aim of this study was to examine th

  7. Database Replication

    CERN Document Server

    Kemme, Bettina

    2010-01-01

    Database replication is widely used for fault-tolerance, scalability and performance. The failure of one database replica does not stop the system from working as available replicas can take over the tasks of the failed replica. Scalability can be achieved by distributing the load across all replicas, and adding new replicas should the load increase. Finally, database replication can provide fast local access, even if clients are geographically distributed clients, if data copies are located close to clients. Despite its advantages, replication is not a straightforward technique to apply, and

  8. Simulating NBTI degradation in arbitrary stressed analog/mixed-signal environments

    NARCIS (Netherlands)

    Wan, Jinbo; Kerkhoff, Hans G.; Wan, Jinbo

    2016-01-01

    A compact negative bias temperature instability (NBTI) model is presented by iteratively solving the RD equations in a simple way. The new compact model can handle arbitrary stress conditions without solving time-consuming equations, and is hence, suitable for analogue/mixed-signal NBTI simulations

  9. An arbitrary stressed NBTI compact model for analog/mixed-signal reliability simulations

    NARCIS (Netherlands)

    Wan, Jinbo; Kerkhoff, Hans G.

    2013-01-01

    A compact NBTI model is presented by directly solving the reaction-diffusion (RD) equations in a simple way. The new model can handle arbitrary stress conditions without solving time-consuming equations and is hence very suitable for analog/mixed-signal NBTI simulations in SPICE-like environments. T

  10. The Role of Ubiquitin and the 26S Proteasome in Plant Abiotic Stress Signaling

    Directory of Open Access Journals (Sweden)

    Stone L Sophia

    2014-04-01

    Full Text Available Ubiquitin is a small, highly conserved, ubiquitously expressed eukaryotic protein with immensely important and diverse regulatory functions. A well-studied function of ubiquitin is its role in selective proteolysis by the ubiquitin-proteasome system (UPS. The UPS has emerged as an integral player in plant response and adaptation to environmental stresses such as drought, salinity, cold and nutrient deprivation. The UPS has also been shown to influence the production and signal transduction of stress-related hormones such as abscisic acid. Understanding UPS function has centered mainly on defining the role of E3 ubiquitin ligases, which are the substrate-recruiting component of the ubiquitination pathway. The recent identification of stress signaling/regulatory proteins that are the subject of ubiquitin-dependent degradation has increased our knowledge of how the UPS facilitate responses to adverse environmental conditions. A brief overview is provided on role of the UPS in modulating protein stability during abiotic stress signaling. E3 ubiquitin ligases for which stress-related substrate proteins have been identified are discussed.

  11. Salt stress sensing and early signalling events in plant roots: Current knowledge and hypothesis.

    Science.gov (United States)

    Shabala, Sergey; Wu, Honghong; Bose, Jayakumar

    2015-12-01

    Soil salinity is a major environmental constraint to crop production. While the molecular identity and functional expression of Na(+) transport systems mediating Na(+) exclusion from the cytosol has been studied in detail, far less is known about the mechanisms by which plants sense high Na(+) levels in the soil and the rapid signalling events that optimise plant performance under saline conditions. This review aims to fill this gap. We first discuss the nature of putative salt stress sensors, candidates which include Na(+) transport systems, mechanosensory proteins, proteins with regulatory Na(+) binding sites, sensing mediated by cyclic nucleotide-gated channels, purine receptors, annexin and voltage gating. We suggest that several transport proteins may be clustered together to form a microdomain in a lipid raft, allowing rapid changes in the activity of an individual protein to be translated into stress-induced Ca(2+) and H2O2 signatures. The pathways of stress signalling to downstream targets are discussed, and the kinetics and specificity of salt stress signalling between glycophytes and halophytes is compared. We argue that these sensing mechanisms operate in parallel, providing plants with a robust system for decoding information about the specific nature and severity of the imposed salt stress.

  12. N-substituted benzyl matrinic acid derivatives inhibit hepatitis C virus (HCV replication through down-regulating host heat-stress cognate 70 (Hsc70 expression.

    Directory of Open Access Journals (Sweden)

    Na-Na Du

    Full Text Available Heat-stress cognate 70 (Hsc70 is a host factor that helps hepatitis C virus (HCV to complete its life cycle in infected hepatocytes. Using Hsc70 as a target for HCV inhibition, a series of novel N-substituted benzyl matrinic/sophoridinic acid derivatives was synthesized and evaluated for their anti-HCV activity in vitro. Among these analogues, compound 7c possessing N-p-methylbenzyl afforded an appealing ability to inhibit HCV replication with SI value over 53. Furthermore, it showed a good oral pharmacokinetic profile with area-under-curve (AUC of 13.4 µM·h, and a considerably good safety in oral administration in mice (LD50>1000 mg/kg. As 7c suppresses HCV replication via an action mode distinctly different from that of the marketed anti-HCV drugs, it has been selected as a new mechanism anti-HCV candidate for further investigation, with an advantage of no or decreased chance to induce drug-resistant mutations.

  13. Silica nanoparticles induce endoplasmic reticulum stress response, oxidative stress and activate the mitogen-activated protein kinase (MAPK signaling pathway

    Directory of Open Access Journals (Sweden)

    Verena Christen

    2014-01-01

    Full Text Available Application of silica nanoparticles (SiO2-NPs may result in human exposure. Here we investigate unexplored modes of action by which SiO2-NPs with average size of 225 nm act on human hepatoma cells (Huh7. We focused on the endoplasmic (ER stress response and on mitogen-activated protein kinase (MAPK signaling pathways. Both pathways were induced. ER stress and the associated three unfolded protein response (UPR pathways were activated as demonstrated by significant inductions of BiP and XBP-1s and a moderate but significant induction of ATF-4 at 0.05 and 0.5 mg/ml. In addition to activation of NFкB interferon stimulated genes IP-10, IRF-9, and ISG-15 were up-regulated. As a consequence of ER stress, the pro-inflammatory cytokine TNFα and PP2Ac were induced following exposure to 0.05 mg/ml SiO2-NPs. Additionally, this occurred at 0.005 mg/ml SiO2-NPs for TNFα at 24 h. This in turn led to a strong transcriptional induction of MAP-kinases and its target genes cJun, cMyc and CREB. A strong transcriptional down-regulation of the proapoptotic gene p53 occurred at 0.05 and 0.5 mg/ml SiO2-NP. Exposure of Huh7 cells to the anti-oxidant N-acetyl cysteine reduced transcriptional induction of ER stress markers demonstrating a link between the induction of oxidative stress and ER stress. Our study demonstrates that SiO2-NPs lead to strong ER stress and UPR induction, oxidative stress, activation of MAPK signaling and down-regulation of p53. All of these activated pathways, which are analyzed here for the first time in detail, inhibit apoptosis and induce cell proliferation, which may contribute to a hepatotoxic, inflammatory and tumorigenic action of SiO2-NPs.

  14. Measurement of heart rate variability and stress evaluation by using microwave reflectometric vital signal sensing

    Science.gov (United States)

    Nagae, Daisuke; Mase, Atsushi

    2010-09-01

    In this paper, we present two robust signal processing techniques for stress evaluation using a microwave reflectometric cardiopulmonary sensing instrument. These techniques enable the heart rate variability (HRV) to be recovered from measurements of body-surface dynamic motion, which is subsequently used for the stress evaluation. Specifically, two novel elements are introduced: one is a reconfiguration of the HRV from the cross-correlation function between a measurement signal and a template signal which is constructed by averaging periodic component over a measurement time. The other is a reconstruction of the HRV from the time variation of the heartbeat frequency; this is evaluated by a repetition of the maximum entropy method. These two signal processing techniques accomplish the reconstruction of the HRV, though they are completely different algorithms. For validations of our model, an experimental setup is presented and several sets of experimental data are analyzed using the two proposed signal processing techniques, which are subsequently used for the stress evaluation. The results presented herein are consistent with electrocardiogram data.

  15. Caregiving and developmental factors differentiating young at-risk urban children showing resilient versus stress-affected outcomes: a replication and extension.

    Science.gov (United States)

    Wyman, P A; Cowen, E L; Work, W C; Hoyt-Meyers, L; Magnus, K B; Fagen, D B

    1999-01-01

    This study tested hypotheses from an organizational-developmental model for childhood resilience. In this model resilience reflects a child's mastery of age-salient objectives, in the face of substantial adversity, by drawing on internal and external resources that enhance processes of adaptation specific to each developmental stage. Interviews were conducted with parents of 122 7- to 9-year-old urban children exposed to multiple risk factors, 69 classified as resilient and 53 as maladjusted. Consistent with predictions generated by the model: (1) characteristics of a child's caregiving system and early development differentiated children with resilient and stress-affected adaptations; and (2) variables reflecting emotionally responsive, competent parenting were direct, proximal predictors of resilient status and mediators of other caregiver resources such as education, mental health, and relational history. Identified predictors of resilient status, including competent parenting and caregiver psychosocial resources, largely replicated findings from a prior study with sociodemographically comparable 9- to 12-year-old children.

  16. Silicon: a duo synergy for regulating crop growth and hormonal signaling under abiotic stress conditions.

    Science.gov (United States)

    Kim, Yoon-Ha; Khan, Abdul Latif; Lee, In-Jung

    2016-12-01

    Abiotic stresses, such as salinity, heavy metals and drought, are some of the most devastating factors hindering sustainable crop production today. Plants use their own defensive strategies to cope with the adverse effects of these stresses, via the regulation of the expression of essential phytohormones, such as gibberellins (GA), salicylic acid (SA), jasmonates (JA), abscisic acid (ABA) and ethylene (ET). However, the efficacy of the endogenous defensive arsenals of plants often falls short if the stress persists over an extended period. Various strategies are developed to improve stress tolerance in plants. For example, silicon (Si) is widely considered to possess significant potential as a substance which ameliorate the negative effects of abiotic stresses, and improves plant growth and biomass accumulation. This review aims to explain how Si application influences the signaling of the endogenous hormones GA, SA, ABA, JA and ET during salinity, wounding, drought and metal stresses in crop plants. Phytohormonal cross talk plays an important role in the regulation of induced defences against stress. However, detailed molecular and proteomic research into these interactions is needed in order to identify the underlying mechanisms of stress tolerance that is imparted by Si application and uptake.

  17. Cluster-based analysis for personalized stress evaluation using physiological signals.

    Science.gov (United States)

    Xu, Qianli; Nwe, Tin Lay; Guan, Cuntai

    2015-01-01

    Technology development in wearable sensors and biosignal processing has made it possible to detect human stress from the physiological features. However, the intersubject difference in stress responses presents a major challenge for reliable and accurate stress estimation. This research proposes a novel cluster-based analysis method to measure perceived stress using physiological signals, which accounts for the intersubject differences. The physiological data are collected when human subjects undergo a series of task-rest cycles, incurring varying levels of stress that is indicated by an index of the State Trait Anxiety Inventory. Next, a quantitative measurement of stress is developed by analyzing the physiological features in two steps: 1) a k -means clustering process to divide subjects into different categories (clusters), and 2) cluster-wise stress evaluation using the general regression neural network. Experimental results show a significant improvement in evaluation accuracy as compared to traditional methods without clustering. The proposed method is useful in developing intelligent, personalized products for human stress management.

  18. Oxidant stress and skeletal muscle glucose transport: roles of insulin signaling and p38 MAPK.

    Science.gov (United States)

    Kim, John S; Saengsirisuwan, Vitoon; Sloniger, Julie A; Teachey, Mary K; Henriksen, Erik J

    2006-09-01

    Oxidative stress can impact the regulation of glucose transport activity in a variety of cell lines. In the present study, we assessed the direct effects of an oxidant stress on the glucose transport system in intact mammalian skeletal muscle preparations. Type IIb (epitrochlearis) and type I (soleus) muscles from insulin-sensitive lean Zucker rats were incubated in 8 mM glucose for 2 h in the absence or presence of 100 mU/ml glucose oxidase to produce the oxidant hydrogen peroxide (H(2)O(2)) (60-90 microM). Glucose transport, glycogen synthase activity, and metabolic signaling factors were then assessed. H(2)O(2) significantly (p oxidant stress was prevented by the PI3-kinase inhibitor wortmannin. The oxidant stress also significantly increased phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) and 5'-AMP-dependent protein kinase. Interestingly, selective inhibition of p38 MAPK using A304000 substantially reduced the activation of glucose transport induced by the oxidant stress. These results support a direct role for oxidative stress in the activation of the glucose transport system in mammalian skeletal muscle and indicate that this process involves engagement of and possible interactions between the PI3-kinase-dependent signaling pathway and activation of p38 MAPK.

  19. Localization of the Carnation Italian ringspot virus replication protein p36 to the mitochondrial outer membrane is mediated by an internal targeting signal and the TOM complex

    Directory of Open Access Journals (Sweden)

    Gidda Satinder K

    2008-09-01

    Full Text Available Abstract Background Carnation Italian ringspot virus (CIRV is a positive-strand RNA virus that causes massive structural alterations of mitochondria in infected host cells, the most conspicuous being the formation of numerous internal vesicles/spherules that are derived from the mitochondrial outer membrane and serve as the sites for viral RNA replication. While the membrane-bound components of the CIRV replication complex, including a 36-kD RNA-binding protein (p36, are known to be essential for these changes in mitochondrial morphology and are relatively well characterized in terms of their roles in nascent viral RNA synthesis, how these proteins are specifically targeted and inserted into mitochondria is poorly defined. Results Here we report on the molecular signal responsible for sorting p36 to the mitochondrial outer membrane. Using a combination of gain-of-function assays with portions of p36 fused to reporter proteins and domain-swapping assays with p36 and another closely-related viral RNA-binding protein, p33, that sorts specifically to the peroxisomal boundary membrane, we show that the mitochondrial targeting information in p36 resides within its two transmembrane domains (TMDs and intervening hydrophilic loop sequence. Comprehensive mutational analysis of these regions in p36 revealed that the primary targeting determinants are the moderate hydrophobicity of both TMDs and the positively-charged face of an amphipathic helix within the intervening loop sequence. We show also using bimolecular fluorescence complementation (BiFC that p36 interacts with certain components of the translocase complex in the mitochondrial outer membrane (TOM, but not with the sorting and assembly machinery (SAM. Conclusion Our results provide insight to how viruses, such as CIRV, exploit specific host-cell protein sorting pathways to facilitate their replication. The characterization of the targeting and insertion of p36 into the mitochondrial outer

  20. Making memories of stressful events: a journey along epigenetic, gene transcription and signaling pathways

    Directory of Open Access Journals (Sweden)

    Johannes M.H.M. eReul

    2014-01-01

    Full Text Available Strong psychologically stressful events are known to have a long-lasting impact on behavior. The consolidation of such, largely adaptive, behavioral responses to stressful events involves changes in gene expression in limbic brain regions such as the hippocampus and amygdala. The underlying molecular mechanisms however were until recently unresolved. More than a decade ago we started to investigate the role of these hormones in signaling and epigenetic mechanisms participating in the effects of stress on gene transcription in hippocampal neurons. We discovered a novel, rapid non-genomic mechanism in which glucocorticoids via glucocorticoid receptors (GRs facilitate signaling of the ERK MAPK signaling pathway to the downstream nuclear kinases MSK1 and Elk-1 in dentate gyrus (DG granule neurons. Activation of this signaling pathway results in serine10 (S10 phosphorylation and lysine14 (K14 acetylation at histone H3 (H3S10p-K14ac, leading to the induction of the immediate early genes c-Fos and Egr-1. In addition, we found a role of the DNA methylation status of gene promoters. A series of studies showed that these molecular mechanisms play a critical role in the long-lasting consolidation of behavioral responses in the forced swim test and Morris water maze. Furthermore, an important role of GABA was found in controlling the epigenetic and gene transcriptional responses to psychological stress. Thus, psychologically stressful events evoke a long-term impact on behavior through changes in hippocampal function brought about by distinct glutamatergic and glucocorticoid-driven changes in epigenetic regulation of gene transcription which are modulated by (local GABAergic interneurons and limbic afferent inputs. These epigenetic processes may play an important role in the etiology of stress-related mental disorders such as major depressive and anxiety disorders like PTSD.

  1. Salicylic Acid-Dependent Plant Stress Signaling via Mitochondrial Succinate Dehydrogenase1[OPEN

    Science.gov (United States)

    Thatcher, Louise F.

    2017-01-01

    Mitochondria are known for their role in ATP production and generation of reactive oxygen species, but little is known about the mechanism of their early involvement in plant stress signaling. The role of mitochondrial succinate dehydrogenase (SDH) in salicylic acid (SA) signaling was analyzed using two mutants: disrupted in stress response1 (dsr1), which is a point mutation in SDH1 identified in a loss of SA signaling screen, and a knockdown mutant (sdhaf2) for SDH assembly factor 2 that is required for FAD insertion into SDH1. Both mutants showed strongly decreased SA-inducible stress promoter responses and low SDH maximum capacity compared to wild type, while dsr1 also showed low succinate affinity, low catalytic efficiency, and increased resistance to SDH competitive inhibitors. The SA-induced promoter responses could be partially rescued in sdhaf2, but not in dsr1, by supplementing the plant growth media with succinate. Kinetic characterization showed that low concentrations of either SA or ubiquinone binding site inhibitors increased SDH activity and induced mitochondrial H2O2 production. Both dsr1 and sdhaf2 showed lower rates of SA-dependent H2O2 production in vitro in line with their low SA-dependent stress signaling responses in vivo. This provides quantitative and kinetic evidence that SA acts at or near the ubiquinone binding site of SDH to stimulate activity and contributes to plant stress signaling by increased rates of mitochondrial H2O2 production, leading to part of the SA-dependent transcriptional response in plant cells. PMID:28209841

  2. Thioredoxin-dependent Redox Regulation of Cellular Signaling and Stress Response through Reversible Oxidation of Methionines

    Energy Technology Data Exchange (ETDEWEB)

    Bigelow, Diana J.; Squier, Thomas C.

    2011-06-01

    Generation of reactive oxygen species (ROS) is a common feature of many forms of stress to which plants are exposed. Successful adaptation to changing environmental conditions requires sensitive sensors of ROS such as protein-bound methionines that are converted to their corresponding methionine sulfoxides, which in turn can influence cellular signaling pathways. Such a signaling protein is calmodulin, which represents an early and central point in calcium signaling pathways important to stress response in plants. We describe recent work elucidating fundamental mechanisms of reversible methionine oxidation within calmodulin, including the sensitivity of individual methionines within plant and animal calmodulin to ROS, the structural and functional consequences of their oxidation, and the interactions of oxidized calmodulin with methionine sulfoxide reductase enzymes.

  3. The allosteric behavior of Fur mediates oxidative stress signal transduction in Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    Simone ePelliciari

    2015-08-01

    Full Text Available The microaerophilic gastric pathogen Helicobacter pylori is exposed to oxidative stress originating from the aerobic environment, the oxidative burst of phagocytes and the formation of reactive oxygen species, catalyzed by iron excess. Accordingly, the expression of genes involved in oxidative stress defense have been repeatedly linked to the ferric uptake regulator Fur. Moreover, mutations in the Fur protein affect the resistance to metronidazole, likely due to loss-of-function in the regulation of genes involved in redox control. Although many advances in the molecular understanding of HpFur function were made, little is known about the mechanisms that enable Fur to mediate the responses to oxidative stress.Here we show that iron-inducible, apo-Fur repressed genes, such as pfr and hydA, are induced shortly after oxidative stress, while their oxidative induction is lost in a fur knockout strain. On the contrary, holo-Fur repressed genes, such as frpB1 and fecA1, vary modestly in response to oxidative stress. This indicates that the oxidative stress signal specifically targets apo-Fur repressed genes, rather than impairing indiscriminately the regulatory function of Fur. Footprinting analyses showed that the oxidative signal strongly impairs the binding affinity of Fur towards apo-operators, while the binding towards holo-operators is less affected. Further evidence is presented that a reduced state of Fur is needed to maintain apo-repression, while oxidative conditions shift the preferred binding architecture of Fur towards the holo-operator binding conformation, even in the absence of iron. Together the results demonstrate that the allosteric regulation of Fur enables transduction of oxidative stress signals in H. pylori, supporting the concept that apo-Fur repressed genes can be considered oxidation inducible Fur regulatory targets. These findings may have important implications in the study of H. pylori treatment and resistance to

  4. Local calcium signals induced by hyper-osmotic stress in mammalian skeletal muscle cells.

    Science.gov (United States)

    Apostol, Simona; Ursu, Daniel; Lehmann-Horn, Frank; Melzer, Werner

    2009-01-01

    Strenuous activitiy of skeletal muscle leads to temporary osmotic dysbalance and isolated skeletal muscle fibers exposed to osmotic stress respond with characteristic micro-domain calcium signals. It has been suggested that osmotic stress targets transverse tubular (TT) dihydropyridine receptors (DHPRs) which normally serve as voltage-dependent activators of Ca release via ryanodine receptor (RyR1s) of the sarcoplasmic reticulum (SR). Here, we pursued this hypothesis by imaging the response to hyperosmotic solutions in both mouse skeletal muscle fibers and myotubes. Ca fluctuations in the cell periphery of fibers exposed to osmotic stress were accompanied by a substantial dilation of the peripheral TT. The Ca signals were completely inhibited by a conditioning depolarization that inactivates the DHPR. Dysgenic myotubes, lacking the DHP-receptor-alpha1-subunit, showed strongly reduced, yet not completely inhibited activity when stimulated with solutions of elevated tonicity. The results point to a modulatory, even though not essential, role of the DHP receptor for osmotic stress-induced Ca signals in skeletal muscle.

  5. Influence of stress on the stray field signals of ferromagnetic materials

    Institute of Scientific and Technical Information of China (English)

    Lihong Dong; Binshi Xu; Shiyun Dong; Qunzhi Chen; Dan Wang

    2008-01-01

    To investigate the influence of stress alone on the stray field signals of ferromagnetic materials, the static tensile tests of 0.45%C steel and 45CrNiMoVA steel fiat-shaped specimens were performed on an MTSSI0 hydraulic testing machine. Hp(y) signals,the normal component of spontaneous stray field, were measured during the testing process by an EMS-2003 metal magnetic mem-ory diagnostic apparatus cooperated with a non-magnetic electric control displacement instrument. Fracture and microstructure were observed by a scanning electronic microscope and a transmission electron microscope, respectively. The relationships between axial applied stress or residual stress measured by X-ray diffraction method and Hp(y) were analyzed. The results indicate that some regu-lar pattern of the magnetic curve is displayed only between applied stress and stray field signals. The magnetic ordering process stops due to dislocation pinning magnetic domain structure, and Hp(y) value unvaried nearly with applied load increasing in the plastic de-formation stage.

  6. mTOR signalling: the molecular interface connecting metabolic stress, aging and cardiovascular diseases.

    Science.gov (United States)

    Yang, Z; Ming, X-F

    2012-12-01

    The continuing increase in the prevalence of obesity and metabolic disorders such as type-II diabetes and an accelerating aging population globally will remain the major contributors to cardiovascular mortality and morbidity in the 21st century. It is well known that aging is highly associated with metabolic and cardiovascular diseases. Growing evidence also shows that obesity and metabolic diseases accelerate aging process. Studies in experimental animal models demonstrate similarity of metabolic and cardiovascular phenotypes in metabolic diseases and old age, e.g. insulin resistance, oxidative stress, chronic low grade inflammation, cardiac hypertrophy, cardiac fibrosis, and heart failure, as well as vascular dysfunctions. Despite intensive research, the molecular mechanisms linking metabolic stress, aging, and ultimately cardiovascular diseases are still elusive. Although the mammalian target of rapamycin (mTOR) signalling is a well known regulator of metabolism and lifespan in model organisms, its central role in linking metabolic stress, aging and cardiovascular diseases is recently emerging. In this article, we review the evidence supporting the role of mTOR signalling as a molecular interface connecting metabolic stress, aging and cardiovascular diseases. The therapeutic potentials of targeting mTOR signalling to protect against metabolic and age-associated cardiovascular diseases are discussed. © 2012 The Authors. obesity reviews © 2012 International Association for the Study of Obesity.

  7. Influence of hypothalamic IL-6/gp130 receptor signaling on the HPA axis response to chronic stress.

    Science.gov (United States)

    Girotti, Milena; Donegan, Jennifer J; Morilak, David A

    2013-07-01

    Abnormal basal activity and stress-evoked reactivity of the hypothalamic-pituitary-adrenal (HPA) axis are often seen in depression, implicating HPA axis dysfunction as a potentially causative or exacerbating factor. Chronic stress is also a factor in depression, but it is not known what may underlie the shift from adaptive to maladaptive HPA activity over the course of chronic stress. Interleukin 6 (IL-6), a stress-inducible cytokine that signals through gp130 and IL-6Rα receptors to activate the JAK/STAT3 signaling cascade, is elevated in some subtypes of depression, and may have a modulatory effect on HPA activation, raising the possibility that IL-6 contributes to depression through effects on the HPA axis. In this study, we examined the effects of three different stress modalities, acute footshock, chronic intermittent cold (CIC) stress and chronic unpredictable stress (CUS) on IL-6 signaling in the hypothalamus. We also investigated whether IL-6 modulates the HPA response to chronic stress, by blocking IL-6 signaling in the brain during CIC stress using either a neutralizing antibody or an inhibitor of STAT3 phosphorylation. We show that IL-6 and STAT3 in the hypothalamus are activated in response to footshock and CUS. We also found that basal IL-6 signaling through the JAK/STAT3 pathway is required for the sustained CORT response to chronic, but not acute, cold stress and therefore is a potential determinant of plasticity in the HPA axis specifically during chronic stress exposure.

  8. The early signal substances induced by heat stress in brains of mice

    Institute of Scientific and Technical Information of China (English)

    Chunxu WANG; Hanxing WANG

    2008-01-01

    To study the effects of early signal substances induced by heat stress in brains of Kunming mice, six-month-old mice (n=72) were pretreated with heat stress and subsequent ischemia/reperfusion by clipping of their bilateral cervical common arteries for 7 min. According to different treatments, animals were randomly divided into four groups: (1) normal control group; (2) heat stress pre-treatment followed by ischemia and reperfusion group (HS/IR); (3) ischemia and reperfusion group (IR); (4) heat stress group (HS). Animals in the later three groups were subdivided into 3 subgroups (1 day, 4 days, 14 days), respectively. The changes in the expression of cAMP res-ponse element binding protein (CREB) and calcitonin gene-related peptide (CGRP) were detected by immuno-histochemistry and computer image analysis methods. The results showed that compared with the normal group, the expressions of CREB in the hippocampal CA1 region increased significantly in the HS, HS/IR and IR groups (P<0.05). Compared to the normal group, heat stress could result in CGRP excretion and redistribution in the cerebrum, with the highest level in the 4 d HS/IR group. Following heat stress, CGRP immunoreactivity was observed in varicose fibers and neuronal perikarya within the CA1 region. The results indicate that heat stress can induce CREB expression, which in turn stimulates CGRP secretion.

  9. Sugar signalling and gene expression in relation to carbohydrate metabolism under abiotic stresses in plants

    Indian Academy of Sciences (India)

    Anil K Gupta; Narinder Kaur

    2005-12-01

    Sucrose is required for plant growth and development. The sugar status of plant cells is sensed by sensor proteins. The signal generated by signal transduction cascades, which could involve mitogen-activated protein kinases, protein phosphatases, Ca2+ and calmodulins, results in appropriate gene expression. A variety of genes are either induced or repressed depending upon the status of soluble sugars. Abiotic stresses to plants result in major alterations in sugar status and hence affect the expression of various genes by down- and up-regulating their expression. Hexokinase-dependent and hexokinase-independent pathways are involved in sugar sensing. Sucrose also acts as a signal molecule as it affects the activity of a proton-sucrose symporter. The sucrose transporter acts as a sucrose sensor and is involved in phloem loading. Fructokinase may represent an additional sensor that bypasses hexokinase phosphorylation especially when sucrose synthase is dominant. Mutants isolated on the basis of response of germination and seedling growth to sugars and reporter-based screening protocols are being used to study the response of altered sugar status on gene expression. Common cis-acting elements in sugar signalling pathways have been identified. Transgenic plants with elevated levels of sugars/sugar alcohols like fructans, raffinose series oligosaccharides, trehalose and mannitol are tolerant to different stresses but have usually impaired growth. Efforts need to be made to have transgenic plants in which abiotic stress responsive genes are expressed only at the time of adverse environmental conditions instead of being constitutively synthesized.

  10. Cross talk between H2O2 and interacting signal molecules under plant stress response

    Directory of Open Access Journals (Sweden)

    Ina eSaxena

    2016-04-01

    Full Text Available It is well established that oxidative stress is an important cause of cellular damage. During stress condition plants have evolved regulatory mechanism to adapt to various environmental stresses. One of the consequences of stress is an increase in the cellular concentration of ROS, which is subsequently converted to H2O2. H2O2 is continuously produced as the by-product of oxidative plant aerobic metabolism. Organelles with a high oxidizing metabolic activity or with an intense rate of electron flow, such as chloroplasts, mitochondria, or peroxisomes are major sources of H2O2 production. H2O2 acts as a versatile molecule because of its dual role in cells. Under normal conditions, H2O2 acts as a key regulator of many biological processes because H2O2 has been identified as an important second messenger in signal transduction networks. In this review we discuss potential roles of H2O2 and other signaling molecule during various stress responses.

  11. Systemic and Local Responses to Repeated HL Stress-Induced Retrograde Signaling in Arabidopsis.

    Science.gov (United States)

    Gordon, Matthew J; Carmody, Melanie; Albrecht, Verónica; Pogson, Barry

    2012-01-01

    CHLOROPLASTS OF LEAVES UNDER HIGH LIGHT STRESS INITIATE SIGNALS TO THE NUCLEI OF BOTH EXPOSED AND DISTAL LEAVES IN ORDER TO ACCLIMATE AGAINST THE POTENTIAL THREAT OF OXIDATIVE DAMAGE: a process known as high light systemic acquired acclimation (HL SAA). This study explores the nature of HL SAA, synergistic interactions with other environmental stresses, and the impact of repeated HL stress on the acclimation response of exposed and distal leaves. This necessitated the development of novel experimental systems to investigate the initiation, perception, and response to HL SAA. These systems were used to investigate the HL SAA response by monitoring the induction of mRNA in distal leaves not exposed to the HL stress. Acclimation to HL is induced within minutes and the response is proportionally dependent on the quality and quantity of light. HL SAA treatments in conjunction with variations in temperature and humidity reveal HL SAA is influenced by fluctuations in humidity. These treatments also result in changes in auxin accumulation and auxin-responsive genes. A key question in retrograde signaling is the extent to which transient changes in light intensity result in a "memory" of the event leading to acclimation responses. Repeated exposure to short term HL resulted in acclimation of the exposed tissue and that of emerging and young leaves (but not older leaves) to HL and oxidative stress.

  12. Role of oxidative stress in impaired insulin signaling associated with exercise-induced muscle damage.

    Science.gov (United States)

    Aoi, Wataru; Naito, Yuji; Yoshikawa, Toshikazu

    2013-12-01

    Skeletal muscle is a major tissue that utilizes blood glucose. A single bout of exercise improves glucose uptake in skeletal muscle through insulin-dependent and insulin-independent signal transduction mechanisms. However, glucose utilization is decreased in muscle damage induced by acute, unaccustomed, or eccentric exercise. The decrease in glucose utilization is caused by decreased insulin-stimulated glucose uptake in damaged muscles with inhibition of the membrane translocation of glucose transporter 4 through phosphatidyl 3-kinase/Akt signaling. In addition to inflammatory cytokines, reactive oxygen species including 4-hydroxy-2-nonenal and peroxynitrate can induce degradation or inactivation of signaling proteins through posttranslational modification, thereby resulting in a disturbance in insulin signal transduction. In contrast, treatment with factors that attenuate oxidative stress in damaged muscle suppresses the impairment of insulin sensitivity. Muscle-damaging exercise may thus lead to decreased endurance capacity and muscle fatigue in exercise, and it may decrease the efficiency of exercise therapy for metabolic improvement.

  13. Cold-Inducible RNA-Binding Protein Bypasses Replicative Senescence in Primary Cells through Extracellular Signal-Regulated Kinase 1 and 2 Activation▿ †

    Science.gov (United States)

    Artero-Castro, Ana; Callejas, Francisco B.; Castellvi, Josep; Kondoh, Hiroshi; Carnero, Amancio; Fernández-Marcos, Pablo J.; Serrano, Manuel; Ramón y Cajal, Santiago; Lleonart, Matilde E.

    2009-01-01

    Embryonic stem cells are immortalized cells whose proliferation rate is comparable to that of carcinogenic cells. To study the expression of embryonic stem cell genes in primary cells, genetic screening was performed by infecting mouse embryonic fibroblasts (MEFs) with a cDNA library from embryonic stem cells. Cold-inducible RNA-binding protein (CIRP) was identified due to its ability to bypass replicative senescence in primary cells. CIRP enhanced extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation, and treatment with an MEK inhibitor decreased the proliferation caused by CIRP. In contrast to CIRP upregulation, CIRP downregulation decreased cell proliferation and resulted in inhibition of phosphorylated ERK1/2 inhibition. This is the first evidence that ERK1/2 activation, through the same mechanism as that described for a Val12 mutant K-ras to induce premature senescence, is able to bypass senescence in the absence of p16INK4a, p21WAF1, and p19ARF upregulation. Moreover, these results show that CIRP functions by stimulating general protein synthesis with the involvement of the S6 and 4E-BP1 proteins. The overall effect is an increase in kinase activity of the cyclin D1-CDK4 complex, which is in accordance with the proliferative capacity of CIRP MEFs. Interestingly, CIRP mRNA and protein were upregulated in a subgroup of cancer patients, a finding that may be of relevance for cancer research. PMID:19158277

  14. Relaxin-3 receptor (RXFP3 signalling mediates stress-related alcohol preference in mice.

    Directory of Open Access Journals (Sweden)

    Andrew W Walker

    Full Text Available Stressful life events are causally linked with alcohol use disorders (AUDs, providing support for a hypothesis that alcohol consumption is aimed at stress reduction. We have previously shown that expression of relaxin-3 mRNA in rat brain correlates with alcohol intake and that central antagonism of relaxin-3 receptors (RXFP3 prevents stress-induced reinstatement of alcohol-seeking. Therefore the objectives of these studies were to investigate the impact of Rxfp3 gene deletion in C57BL/6J mice on baseline and stress-related alcohol consumption. Male wild-type (WT and Rxfp3 knockout (KO (C57/B6JRXFP3TM1/DGen littermate mice were tested for baseline saccharin and alcohol consumption and preference over water in a continuous access two-bottle free-choice paradigm. Another cohort of mice was subjected to repeated restraint followed by swim stress to examine stress-related alcohol preference. Hepatic alcohol and aldehyde dehydrogenase activity was assessed in mice following chronic alcohol intake and in naive controls. WT and Rxfp3 KO mice had similar baseline saccharin and alcohol preference, and hepatic alcohol processing. However, Rxfp3 KO mice displayed a stress-induced reduction in alcohol preference that was not observed in WT littermates. Notably, this phenotype, once established, persisted for at least six weeks after cessation of stress exposure. These findings suggest that in mice, relaxin-3/RXFP3 signalling is involved in maintaining high alcohol preference during and after stress, but does not appear to strongly regulate the primary reinforcing effects of alcohol.

  15. Sensitivity of Saccharomyces cerevisiae defective in TOR signaling pathway to carbonyl/oxidative stress

    Directory of Open Access Journals (Sweden)

    Valishkevych B. V.

    2014-09-01

    Full Text Available Aim. To investigate the influence of carbonyl/oxidative stress induced by glyoxal, methylglyoxal and hydrogen peroxide on the survival of Saccharomyces cerevisiae, defective for different parts of TOR- signaling pathway, grown on glucose or fructose. Methods. The assessment of number of colony-forming units to determine the yeast reproductive ability. Results. It was shown that at certain concentrations the mentioned above toxicants caused an increase in yeast survival, indicating the hormetic effect. Conclusions. The TOR signaling pathway is involved in the hormetic effect, but it is specific for each strain and depends on the type of carbohydrate in the incubation medium.

  16. Novel roles for phospholipase C in plant stress signalling and development

    OpenAIRE

    Zhang, Q

    2017-01-01

    For many years, efforts have been made to explore PLC signaling in plants. Compared to the classical PLC signaling pathway, a different picture is emerging for plants. Several roles for PLC in plant development and stress responses have been claimed but genetic evidence for this is mostly missing. In this thesis, we functionally characterized the role of PLC3, PLC5 and PLC7 in Arabidopsis. PLC3 (Chapter 2) was mainly expressed in vasculature. Loss-of-function mutants showed delayed seed germi...

  17. Tula hantavirus triggers pro-apoptotic signals of ER stress in Vero E6 cells.

    Science.gov (United States)

    Li, Xiao-Dong; Lankinen, Hilkka; Putkuri, Niina; Vapalahti, Olli; Vaheri, Antti

    2005-03-01

    Tula virus is a member of the Hantavirus genus of the family Bunyaviridae. Viruses of this family have an unusual pattern of intracellular maturation at the ER-Golgi compartment. We recently found that Tula virus, similar to several other hantaviruses, is able to induce apoptosis in cultured cells [Li, X.D., Kukkonen, S., Vapalahti, O., Plyusnin, A., Lankinen, H., Vaheri, A., 2004. Tula hantavirus infection of Vero E6 cells induces apoptosis involving caspase 8 activation. J. Gen. Virol. 85, 3261-3268.]. However, the cellular mechanisms remain to be clarified. In this study, we demonstrate that the progressive replication of Tula virus in Vero E6 cells initiates several death programs that are intimately associated with ER stress: (1) early activation of ER-resident caspase-12; (2) phosphorylation of Jun NH2-terminal kinase (JNK) and its downstream target transcriptional factor, c-jun; (3) induction of the pro-apoptotic transcriptional factor, growth arrest- and DNA damage-inducible gene 153, or C/EBP homologous protein (Gadd153/chop); and (4) changes in the ER-membrane protein BAP31 implying cross-talk with the mitochondrial apoptosis pathway. Furthermore, we confirmed that a sustained ER stress was induced marked by an increased expression of an ER chaperone Grp78/BiP. Taken together, we have identified involvement of ER stress-mediated death program in Tula virus-infected Vero E6 cells which provides a new approach to understand the mechanisms in hantavirus-induced apoptosis.

  18. Activation of PI3K/AKT and ERK MAPK signal pathways is required for the induction of lytic cycle replication of Kaposi's Sarcoma-associated herpesvirus by herpes simplex virus type 1

    Directory of Open Access Journals (Sweden)

    Lv Zhigang

    2011-10-01

    Full Text Available Abstract Background Kaposi's sarcoma-associated herpesvirus (KSHV is causally linked to several acquired immunodeficiency syndrome-related malignancies, including Kaposi's sarcoma (KS, primary effusion lymphoma (PEL and a subset of multicentric Castleman's disease. Regulation of viral lytic replication is critical to the initiation and progression of KS. Recently, we reported that herpes simplex virus type 1 (HSV-1 was an important cofactor that activated lytic cycle replication of KSHV. Here, we further investigated the possible signal pathways involved in HSV-1-induced reactivation of KSHV. Results By transfecting a series of dominant negative mutants and protein expressing constructs and using pharmacologic inhibitors, we found that either Janus kinase 1 (JAK1/signal transducer and activator of transcription 3 (STAT3 or JAK1/STAT6 signaling failed to regulate HSV-1-induced KSHV replication. However, HSV-1 infection of BCBL-1 cells activated phosphatidylinositol 3-kinase (PI3K/protein kinase B (PKB, also called AKT pathway and inactivated phosphatase and tensin homologue deleted on chromosome ten (PTEN and glycogen synthase kinase-3β (GSK-3β. PTEN/PI3K/AKT/GSK-3β pathway was found to be involved in HSV-1-induced KSHV reactivation. Additionally, extracellular signal-regulated protein kinase (ERK mitogen-activated protein kinase (MAPK pathway also partially contributed to HSV-1-induced KSHV replication. Conclusions HSV-1 infection stimulated PI3K/AKT and ERK MAPK signaling pathways that in turn contributed to KSHV reactivation, which provided further insights into the molecular mechanism controlling KSHV lytic replication, particularly in the context of HSV-1 and KSHV co-infection.

  19. Reconstruction of stress corrosion cracks using signals of pulsed eddy current testing

    Science.gov (United States)

    Wang, Li; Xie, Shejuan; Chen, Zhenmao; Li, Yong; Wang, Xiaowei; Takagi, Toshiyuki

    2013-06-01

    A scheme to apply signals of pulsed eddy current testing (PECT) to reconstruct a deep stress corrosion crack (SCC) is proposed on the basis of a multi-layer and multi-frequency reconstruction strategy. First, a numerical method is introduced to extract conventional eddy current testing (ECT) signals of different frequencies from the PECT responses at different scanning points, which are necessary for multi-frequency ECT inversion. Second, the conventional fast forward solver for ECT signal simulation is upgraded to calculate the single-frequency pickup signal of a magnetic field by introducing a strategy that employs a tiny search coil. Using the multiple-frequency ECT signals and the upgraded fast signal simulator, we reconstructed the shape profiles and conductivity of an SCC at different depths layer-by-layer with a hybrid inversion scheme of the conjugate gradient and particle swarm optimisation. Several modelled SCCs of rectangular or stepwise shape in an SUS304 plate are reconstructed from simulated PECT signals with artificial noise. The reconstruction results show better precision in crack depth than the conventional ECT inversion method, which demonstrates the validity and efficiency of the proposed PECT inversion scheme.

  20. Oxidative stress and DNA damage signalling in skeletal muscle in pressure-induced deep tissue injury.

    Science.gov (United States)

    Sin, Thomas K; Pei, Xiao M; Teng, Bee T; Tam, Eric W; Yung, Benjamin Y; Siu, Parco M

    2013-02-01

    The molecular mechanisms that contribute to the pathogenesis of pressure-induced deep tissue injury are largely unknown. This study tested the hypothesis that oxidative stress and DNA damage signalling mechanism in skeletal muscle are involved in deep tissue injury. Adult Sprague Dawley rats were subject to an experimental protocol to induce deep tissue injury. Two compression cycles with a static pressure of 100 mmHg was applied to an area of 1.5 cm(2) over the mid-tibialis region of right limb of the rats. The left uncompressed limb served as intra-animal control. Muscle tissues underneath compression region were collected for examination. Our analyses indicated that pathohistological characteristics including rounding contour of myofibres and extensive nuclei accumulation were apparently shown in compressed muscles. The elevation of 8OHdG immunopositively stained nuclei indicated the presence of oxidative DNA damage. Increase in oxidative stress was revealed by showing significant elevation of 4HNE and decreases in mRNA abundance of SOD1, catalase and GPx, and protein content of SOD2 in compressed muscles relative to control muscles. Increase in nitrosative stress was demonstrated by significant elevation of nitrotyrosine and NOS2 mRNA content. The activation of tumor suppressor p53 signalling was indicated by the remarkable increases in protein contents of total p53 and serine-15 phosphorylated p53. The transcript expression of the DNA-repairing enzyme, Rad23A, was significantly suppressed in compressed muscles. Our time-course study indicated that increased oxidative/nitrosative stress and proapoptotic signalling were maintained in muscles receiving increasing amount of compression cycles and post-compression time. Furthermore, resveratrol was found to attenuate the histological damage, oxidative/nitrosative stress and proapoptotic signalling in response to prolonged moderate compression. In conclusion, our findings are consistent with the hypothesis that

  1. S-Nitrosylation: NO-Related Redox Signaling to Protect Against Oxidative Stress

    OpenAIRE

    2006-01-01

    Nitric oxide (NO) plays an important role in the regulation of cardiovascular function. S-nitrosylation, the covalent attachment of an NO moiety to sulfhydryl residues of proteins, resulting in the formation of S-nitrosothiols (SNOs), is a prevalent posttranslational protein modification involved in redox-based cellular signaling. Under physiologic conditions, protein S>-nitrosylation and SNOs provide protection preventing further cellular oxidative and nitrosative stress. However, oxidative ...

  2. Neuroendocrine Control of the Gut During Stress: Corticotropin-Releasing Factor Signaling Pathways in the Spotlight

    OpenAIRE

    2009-01-01

    Stress affects the gastrointestinal tract as part of the visceral response. Various stressors induce similar profiles of gut motor function alterations, including inhibition of gastric emptying, stimulation of colonic propulsive motility, and hypersensitivity to colorectal distension. In recent years, substantial progress has been made in our understanding of the underlying mechanisms of stress’s impact on gut function. Activation of corticotropin-releasing factor (CRF) signaling pathways med...

  3. Isometric stress in cardiovascular magnetic resonance - a simple and easily replicable method of assessing cardiovascular differences not apparent at rest

    Energy Technology Data Exchange (ETDEWEB)

    Mortensen, Kristian H.; Jones, Alexander; Steeden, Jennifer A.; Taylor, Andrew M.; Muthurangu, Vivek [UCL Centre for Cardiovascular MR, UCL Institute of Cardiovascular Science, Level 6 Old Nurses Home, Cardiorespiratory Unit, Great Ormond Street Hospital for Children, London (United Kingdom)

    2016-04-15

    Isometric exercise may unmask cardiovascular disease not evident at rest, and cardiovascular magnetic resonance (CMR) imaging is proven for comprehensive resting assessment. This study devised a simple isometric exercise CMR methodology and assessed the hemodynamic response evoked by isometric exercise. A biceps isometric exercise technique was devised for CMR, and 75 healthy volunteers were assessed at rest, after 3-minute biceps exercise, and 5-minute of recovery using: (1) blood pressure (BP) and (2) CMR measured aortic flow and left ventricular function. Total peripheral resistance (SVR) and arterial compliance (TAC), cardiac output (CO), left ventricular volumes and function (ejection fraction, stroke volume, power output), blood pressure (BP), heart rate (HR), and rate pressure product were assessed at all time points. Image quality was preserved during stress. During exercise there were increases in CO (+14.9 %), HR (+17.0 %), SVR (+9.8 %), systolic BP (+22.4 %), diastolic BP (+25.4 %) and mean BP (+23.2 %). In addition, there were decreases in TAC (-22.0 %) and left ventricular ejection fraction (-6.3 %). Age and body mass index modified the evoked response, even when resting measures were similar. Isometric exercise technique evokes a significant cardiovascular response in CMR, unmasking physiological differences that are not apparent at rest. (orig.)

  4. Inactivation of p53 in Human Keratinocytes Leads to Squamous Differentiation and Shedding via Replication Stress and Mitotic Slippage.

    Science.gov (United States)

    Freije, Ana; Molinuevo, Rut; Ceballos, Laura; Cagigas, Marta; Alonso-Lecue, Pilar; Rodriguez, René; Menendez, Pablo; Aberdam, Daniel; De Diego, Ernesto; Gandarillas, Alberto

    2014-11-20

    Tumor suppressor p53 is a major cellular guardian of genome integrity, and its inactivation is the most frequent genetic alteration in cancer, rising up to 80% in squamous cell carcinoma (SCC). By adapting the small hairpin RNA (shRNA) technology, we inactivated endogenous p53 in primary epithelial cells from the epidermis of human skin. We show that either loss of endogenous p53 or overexpression of a temperature-sensitive dominant-negative conformation triggers a self-protective differentiation response, resulting in cell stratification and expulsion. These effects follow DNA damage and exit from mitosis without cell division. p53 preserves the proliferative potential of the stem cell compartment and limits the power of proto-oncogene MYC to drive cell cycle stress and differentiation. The results provide insight into the role of p53 in self-renewal homeostasis and help explain why p53 mutations do not initiate skin cancer but increase the likelihood that cancer cells will appear.

  5. Inactivation of p53 in Human Keratinocytes Leads to Squamous Differentiation and Shedding via Replication Stress and Mitotic Slippage

    Directory of Open Access Journals (Sweden)

    Ana Freije

    2014-11-01

    Full Text Available Tumor suppressor p53 is a major cellular guardian of genome integrity, and its inactivation is the most frequent genetic alteration in cancer, rising up to 80% in squamous cell carcinoma (SCC. By adapting the small hairpin RNA (shRNA technology, we inactivated endogenous p53 in primary epithelial cells from the epidermis of human skin. We show that either loss of endogenous p53 or overexpression of a temperature-sensitive dominant-negative conformation triggers a self-protective differentiation response, resulting in cell stratification and expulsion. These effects follow DNA damage and exit from mitosis without cell division. p53 preserves the proliferative potential of the stem cell compartment and limits the power of proto-oncogene MYC to drive cell cycle stress and differentiation. The results provide insight into the role of p53 in self-renewal homeostasis and help explain why p53 mutations do not initiate skin cancer but increase the likelihood that cancer cells will appear.

  6. Chronic stress induces anxiety via an amygdalar intracellular cascade that impairs endocannabinoid signaling.

    Science.gov (United States)

    Qin, Zhaohong; Zhou, Xun; Pandey, Nihar R; Vecchiarelli, Haley A; Stewart, Chloe A; Zhang, Xia; Lagace, Diane C; Brunel, Jean Michel; Béïque, Jean-Claude; Stewart, Alexandre F R; Hill, Matthew N; Chen, Hsiao-Huei

    2015-03-18

    Collapse of endocannabinoid (eCB) signaling in the amygdala contributes to stress-induced anxiety, but the mechanisms of this effect remain unclear. eCB production is tied to the function of the glutamate receptor mGluR5, itself dependent on tyrosine phosphorylation. Herein, we identify a novel pathway linking eCB regulation of anxiety through phosphorylation of mGluR5. Mice lacking LMO4, an endogenous inhibitor of the tyrosine phosphatase PTP1B, display reduced mGluR5 phosphorylation, eCB signaling, and profound anxiety that is reversed by genetic or pharmacological suppression of amygdalar PTP1B. Chronically stressed mice exhibited elevated plasma corticosterone, decreased LMO4 palmitoylation, elevated PTP1B activity, reduced amygdalar eCB levels, and anxiety behaviors that were restored by PTP1B inhibition or by glucocorticoid receptor antagonism. Consistently, corticosterone decreased palmitoylation of LMO4 and its inhibition of PTP1B in neuronal cells. Collectively, these data reveal a stress-responsive corticosterone-LMO4-PTP1B-mGluR5 cascade that impairs amygdalar eCB signaling and contributes to the development of anxiety. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Role of Paraventricular Nucleus Glutamate Signaling in Regulation of HPA Axis Stress Responses.

    Science.gov (United States)

    Evanson, Nathan K; Herman, James P

    The hypothalamus-pituitary-adrenal (HPA) axis is the main neuroendocrine arm of the stress response, activation of which leads to the production of glucocorticoid hormones. Glucocorticoids are steroid hormones that are secreted from the adrenal cortex, and have a variety of effects on the body, including modulation of the immune system, suppression of reproductive hormones maintenance of blood glucose levels, and maintenance of blood pressure. Glutamate plays an important role in coordination of HPA axis output. There is strong evidence that glutamate drives HPA axis stress responses through excitatory signaling via ionotropic glutamate receptor signaling. However, glutamate signaling via kainate receptors and group I metabotropic receptors inhibit HPA drive, probably via presynaptic inhibitory mechanisms. Notably, kainate receptors are also localized in the median eminence, and appear to play an excitatory role in control of CRH release at the nerve terminals. Finally, glutamate innervation of the PVN undergoes neuroplastic changes under conditions of chronic stress, and may be involved in sensitization of HPA axis responses. Altogether, the data suggest that glutamate plays a complex role in excitation of CRH neurons, acting at multiple levels to both drive HPA axis responses and limit over-activation.

  8. Stress-induced glucocorticoids as a neuroendocrine alarm signal of danger.

    Science.gov (United States)

    Frank, Matthew G; Watkins, Linda R; Maier, Steven F

    2013-10-01

    A considerable number of studies demonstrate that acute and chronic stressors prime CNS innate immune responses to subsequent pro-inflammatory challenges and that glucocorticoids mediate, in part, stress-induced sensitization of pro-inflammatory immune responses. Here, we explore the notion that GCs produce a persisting sensitization of CNS innate immune effectors (e.g. microglia) so that they will generate a potentiated pro-inflammatory response after the GC rise has dissipated, thereby enhancing the sickness response to infection or injury and maximizing the animal's ability to neutralize danger. The stress-induced GC response is conceptualized here as an neuroendocrine warning signal or alarmin to the innate immune system, which prepares or sensitizes the innate immune response to potential danger. Thus, a new understanding of the stress response and its function (priming CNS innate immune responses to infection or injury during a fight/flight emergency) would be suggested.

  9. Fine-Tuning ER Stress Signal Transducers to Treat Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Danilo B. Medinas

    2017-07-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is a fatal neurodegenerative disease characterized by the progressive loss of motoneurons and paralysis. The mechanisms underlying neuronal degeneration in ALS are starting to be elucidated, highlighting disturbances in motoneuron proteostasis. Endoplasmic reticulum (ER stress has emerged as an early pathogenic event underlying motoneuron vulnerability and denervation in ALS. Maintenance of ER proteostasis is controlled by a dynamic signaling network known as the unfolded protein response (UPR. Inositol-requiring enzyme 1 (IRE1 is an ER-located kinase and endoribonuclease that operates as a major ER stress transducer, mediating the establishment of adaptive and pro-apoptotic programs. Here we discuss current evidence supporting the role of ER stress in motoneuron demise in ALS and build the rational to target IRE1 to ameliorate neurodegeneration.

  10. Specificity in stress response: epidermal keratinocytes exhibit specialized UV-responsive signal transduction pathways.

    Science.gov (United States)

    Adachi, Makoto; Gazel, Alix; Pintucci, Giuseppe; Shuck, Alyssa; Shifteh, Shiva; Ginsburg, Dov; Rao, Laxmi S; Kaneko, Takehiko; Freedberg, Irwin M; Tamaki, Kunihiko; Blumenberg, Miroslav

    2003-10-01

    UV light, a paradigmatic initiator of cell stress, invokes responses that include signal transduction, activation of transcription factors, and changes in gene expression. Consequently, in epidermal keratinocytes, its principal and frequent natural target, UV regulates transcription of a distinctive set of genes. Hypothesizing that UV activates distinctive epidermal signal transduction pathways, we compared the UV-responsive activation of the JNK and NFkappaB pathways in keratinocytes, with the activation of the same pathways by other agents and in other cell types. Using of inhibitors and antisense oligonucleotides, we found that in keratinocytes only UVB/UVC activate JNK, while in other cell types UVA, heat shock, and oxidative stress do as well. Keratinocytes express JNK-1 and JNK-3, which is unexpected because JNK-3 expression is considered brain-specific. In keratinocytes, ERK1, ERK2, and p38 are activated by growth factors, but not by UV. UVB/UVC in keratinocytes activates Elk1 and AP1 exclusively through the JNK pathway. JNKK1 is essential for UVB/UVC activation of JNK in keratinocytes in vitro and in human skin in vivo. In contrast, in HeLa cells, used as a control, crosstalk among signal transduction pathways allows considerable laxity. In parallel, UVB/UVC and TNFalpha activate the NFkappaB pathway via distinct mechanisms, as shown using antisense oligonucleotides targeted against IKKbeta, the active subunit of IKK. This implies a specific UVB/UVC responsive signal transduction pathway independent from other pathways. Our results suggest that in epidermal keratinocytes specific signal transduction pathways respond to UV light. Based on these findings, we propose that the UV light is not a genetic stress response inducer in these cells, but a specific agent to which epidermis developed highly specialized responses.

  11. ISG12a inhibits HCV replication and potentiates the anti-HCV activity of IFN-α through activation of the Jak/STAT signaling pathway independent of autophagy and apoptosis.

    Science.gov (United States)

    Chen, Yanzhao; Jiao, Baihai; Yao, Min; Shi, Xuezhen; Zheng, Zhebin; Li, Shilin; Chen, Limin

    2017-01-02

    Interferon stimulated (sensitive) genes (ISGs) are the effector molecules downstream of type I/III interferon (IFN) signaling pathways in host innate immunity. ISG12a can be induced by IFN-α. Although ISG12a has been reported to inhibit the replication of HCV, the exact mechanism remains to be determined. In this study, we investigated the possible mechanisms of ISG12a anti- HCV property by exploring the production of type I IFN and the activation of Janus kinase/signal transducer and activator of transcription (Jak/STAT) signaling pathway, apoptosis and autophagy in Huh7.5.1 cells transiently transfected with ISG12a over-expression plasmid. Interestingly, we found that ISG12a inhibited HCV replication in both Con1b replicon and the HCV JFH1-based cell culture system and potentiated the anti-HCV activity of IFN-α. ISG12a promoted the production of IFN α/β and activated the type I IFN signaling pathway as shown by increased p-STAT1 level, higher Interferon sensitive response element (ISRE) activity and up-regulated ISG levels. However, ISG12a over-expression did not affect cell autophagy and apoptosis. Data from our current study collectively indicated that ISG12a inhibited HCV replication and potentiated the anti-HCV activity of IFN-α possibly through induced production of type I IFNs and activation of Jak/STAT signaling pathway independent of autophagy and cell apoptosis.

  12. NOD1 and NOD2 signalling links ER stress with inflammation.

    Science.gov (United States)

    Keestra-Gounder, A Marijke; Byndloss, Mariana X; Seyffert, Núbia; Young, Briana M; Chávez-Arroyo, Alfredo; Tsai, April Y; Cevallos, Stephanie A; Winter, Maria G; Pham, Oanh H; Tiffany, Connor R; de Jong, Maarten F; Kerrinnes, Tobias; Ravindran, Resmi; Luciw, Paul A; McSorley, Stephen J; Bäumler, Andreas J; Tsolis, Renée M

    2016-04-21

    Endoplasmic reticulum (ER) stress is a major contributor to inflammatory diseases, such as Crohn disease and type 2 diabetes. ER stress induces the unfolded protein response, which involves activation of three transmembrane receptors, ATF6, PERK and IRE1α. Once activated, IRE1α recruits TRAF2 to the ER membrane to initiate inflammatory responses via the NF-κB pathway. Inflammation is commonly triggered when pattern recognition receptors (PRRs), such as Toll-like receptors or nucleotide-binding oligomerization domain (NOD)-like receptors, detect tissue damage or microbial infection. However, it is not clear which PRRs have a major role in inducing inflammation during ER stress. Here we show that NOD1 and NOD2, two members of the NOD-like receptor family of PRRs, are important mediators of ER-stress-induced inflammation in mouse and human cells. The ER stress inducers thapsigargin and dithiothreitol trigger production of the pro-inflammatory cytokine IL-6 in a NOD1/2-dependent fashion. Inflammation and IL-6 production triggered by infection with Brucella abortus, which induces ER stress by injecting the type IV secretion system effector protein VceC into host cells, is TRAF2, NOD1/2 and RIP2-dependent and can be reduced by treatment with the ER stress inhibitor tauroursodeoxycholate or an IRE1α kinase inhibitor. The association of NOD1 and NOD2 with pro-inflammatory responses induced by the IRE1α/TRAF2 signalling pathway provides a novel link between innate immunity and ER-stress-induced inflammation.

  13. Satellites Seek Gravity Signals for Remote Sensing the Seismotectonic Stresses in Earth

    Science.gov (United States)

    Liu, H.; Chen, J.; Li, J.

    2003-12-01

    The ability of the mantle to withstand stress-difference due to superimposed loads would appear to argue against flow in the Earth's mantle, but the ironic fact is that the satellite determined gravity variations are the evidence of density differences associated with mantle flow. The type of flow which is most likely to be involved concerns convection currents. For the past 4 decades, models of mantle convection have made remarkable advancements. Although a large body of evidence regarding the seafloor depth, heat flow, lithospheric strength and forces of slab-pull and swell-push has been obtained, the global seismotectonic stresses in the Earth are yet to be determined. The problem is that no one has been able to come up with a satisfactory scenario that must characterize the stresses in the Earth which cause earthquakes and create tectonic features. The stress generated by mantle convection under the crust are inferable from high degree (n>=13) spherical harmonics of the geopotential. Therefore, satellite gravity missions may be able to seek the Earth's gravity signals for investigating the seismotectonic effect of these subcrustal stresses. It is well known that subcrustal stress patterns for (137.0 from 1976 to 2000 is also given for reference. The intense seismicity in the subcrustal stress concentration belt (the ring of fire around the Pacific) is expected. A broad band of seismicity extends from southern Europe to southeast Europe to southeast Asia; this is associated with the subcrustal stress concentration belts in Europe, Africa, Arabian, and Asia. These results seem to provide significant insights into the origin of the earthquakes and formation of the world.

  14. The Pepper CaOSR1 Protein Regulates the Osmotic Stress Response via Abscisic Acid Signaling.

    Science.gov (United States)

    Park, Chanmi; Lim, Chae Woo; Lee, Sung Chul

    2016-01-01

    Plants are sessile organisms, and their growth and development is detrimentally affected by environmental stresses such as drought and high salinity. Defense mechanisms are tightly regulated and complex processes, which respond to changing environmental conditions; however, the precise mechanisms that function under adverse conditions remain unclear. Here, we report the identification and functional characterization of the CaOSR1 gene, which functions in the adaptive response to abiotic stress. We found that CaOSR1 gene expression in pepper leaves was up-regulated after exposure to abscisic acid (ABA), drought, and high salinity. In addition, we demonstrated that the fusion protein of CaOSR1 with green fluorescent protein (GFP) is localized in the nucleus. We used CaOSR1-silenced pepper plants and CaOSR1-OX-overexpressing (OX) transgenic Arabidopsis plants to show that the CaOSR1 protein regulates the osmotic stress response. CaOSR1-silenced pepper plants showed increased drought susceptibility, and this was accompanied by a high transpiration rate. CaOSR1-OX plants displayed phenotypes that were hypersensitive to ABA and hyposensitive to osmotic stress, during the seed germination and seedling growth stages; furthermore, these plants exhibited enhanced drought tolerance at the adult stage, and this was characterized by higher leaf temperatures and smaller stomatal apertures because of ABA hypersensitivity. Taken together, our data indicate that CaOSR1 positively regulates osmotic stress tolerance via ABA-mediated cell signaling. These findings suggest an involvement of a novel protein in ABA and osmotic stress signalings in plants.

  15. Plant resistance to cold stress: Mechanisms and environmental signals triggering frost hardening and dehardening

    Indian Academy of Sciences (India)

    Erwin H Beck; Richard Heim; Jens Hansen

    2004-12-01

    This introductory overview shows that cold, in particular frost, stresses a plant in manifold ways and that the plant’s response, being injurious or adaptive, must be considered a syndrome rather than a single reaction. In the course of the year perennial plants of the temperate climate zones undergo frost hardening in autumn and dehardening in spring. Using Scots pine (Pinus sylvestris L.) as a model plant the environmental signals inducing frost hardening and dehardening, respectively, were investigated. Over 2 years the changes in frost resistance of Scots pine needles were recorded together with the annual courses of day-length and ambient temperature. Both act as environmental signals for frost hardening and dehardening. Climate chamber experiments showed that short day-length as a signal triggering frost hardening could be replaced by irradiation with far red light, while red light inhibited hardening. The involvement of phytochrome as a signal receptor could be corroborated by respective night-break experiments. More rapid frost hardening than by short day or far red treatment was achieved by applying a short period (6 h) of mild frost which did not exceed the plant’s cold resistance. Both types of signals were independently effective but the rates of frost hardening were not additive. The maximal rate of hardening was – 0.93°C per day and frost tolerance of < – 72°C was achieved. For dehardening, temperature was an even more effective signal than day-length.

  16. A novel transcription factor, ERD15 (Early Responsive to Dehydration 15), connects endoplasmic reticulum stress with an osmotic stress-induced cell death signal.

    Science.gov (United States)

    Alves, Murilo S; Reis, Pedro A B; Dadalto, Silvana P; Faria, Jerusa A Q A; Fontes, Elizabeth P B; Fietto, Luciano G

    2011-06-03

    As in all other eukaryotic organisms, endoplasmic reticulum (ER) stress triggers the evolutionarily conserved unfolded protein response in soybean, but it also communicates with other adaptive signaling responses, such as osmotic stress-induced and ER stress-induced programmed cell death. These two signaling pathways converge at the level of gene transcription to activate an integrated cascade that is mediated by N-rich proteins (NRPs). Here, we describe a novel transcription factor, GmERD15 (Glycine max Early Responsive to Dehydration 15), which is induced by ER stress and osmotic stress to activate the expression of NRP genes. GmERD15 was isolated because of its capacity to stably associate with the NRP-B promoter in yeast. It specifically binds to a 187-bp fragment of the NRP-B promoter in vitro and activates the transcription of a reporter gene in yeast. Furthermore, GmERD15 was found in both the cytoplasm and the nucleus, and a ChIP assay revealed that it binds to the NRP-B promoter in vivo. Expression of GmERD15 in soybean protoplasts activated the NRP-B promoter and induced expression of the NRP-B gene. Collectively, these results support the interpretation that GmERD15 functions as an upstream component of stress-induced NRP-B-mediated signaling to connect stress in the ER to an osmotic stress-induced cell death signal.

  17. The prostacyclin agonist iloprost aggravates fibrosis and enhances viral replication in enteroviral myocarditis by modulation of ERK signaling and increase of iNOS expression.

    Science.gov (United States)

    Gruhle, Stefan; Sauter, Martina; Szalay, Gudrun; Ettischer, Nicole; Kandolf, Reinhard; Klingel, Karin

    2012-09-01

    Enteroviruses, such as coxsackieviruses of group B (CVB), are able to induce a chronic inflammation of the myocardium, which may finally lead to the loss of functional tissue, remodeling processes and the development of fibrosis, thus affecting the proper contractile function of the heart. In other fibrotic diseases like scleroderma, the prostacyclin agonist iloprost was found to inhibit the extracellular signal-regulated kinase (ERK, p44/42 MAPK), a mitogen-activated protein kinase, and consecutively, the expression of the profibrotic cytokine connective tissue growth factor (CTGF), thereby preventing the development of fibrosis. As CTGF was found to mediate fibrosis in chronic CVB3 myocarditis as well, we evaluated whether the in vivo application of iloprost is capable to reduce the development of ERK/CTGF-mediated fibrosis in enteroviral myocarditis. Unexpectedly, the application of iloprost resulted in a prolonged myocardial inflammation and an aggravated fibrosis and failed to reduce activation of ERK and expression of CTGF at later stages of the disease. In addition, viral replication was found to be increased in iloprost-treated mice. Notably, the expression of cardiac inducible nitric oxide synthase (iNOS), which is known to aggravate myocardial damage in CVB3-infected mice, was strongly enhanced by iloprost. Using cultivated bone marrow macrophages (BMM), we confirmed these results, proving that iloprost potentiates the expression of iNOS mRNA and protein in CVB3-infected and IFN-gamma stimulated BMM. In conclusion, these results suggest a critical reflection of the clinical use of iloprost, especially in patients possibly suffering from an enteroviral myocarditis.

  18. Genome-Wide Analysis of the TORC1 and Osmotic Stress Signaling Network in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Jeremy Worley

    2016-02-01

    Full Text Available The Target of Rapamycin kinase Complex I (TORC1 is a master regulator of cell growth and metabolism in eukaryotes. Studies in yeast and human cells have shown that nitrogen/amino acid starvation signals act through Npr2/Npr3 and the small GTPases Gtr1/Gtr2 (Rags in humans to inhibit TORC1. However, it is unclear how other stress and starvation stimuli inhibit TORC1, and/or act in parallel with the TORC1 pathway, to control cell growth. To help answer these questions, we developed a novel automated pipeline and used it to measure the expression of a TORC1-dependent ribosome biogenesis gene (NSR1 during osmotic stress in 4700 Saccharomyces cerevisiae strains from the yeast knock-out collection. This led to the identification of 440 strains with significant and reproducible defects in NSR1 repression. The cell growth control and stress response proteins deleted in these strains form a highly connected network, including 56 proteins involved in vesicle trafficking and vacuolar function; 53 proteins that act downstream of TORC1 according to a rapamycin assay—including components of the HDAC Rpd3L, Elongator, and the INO80, CAF-1 and SWI/SNF chromatin remodeling complexes; over 100 proteins involved in signaling and metabolism; and 17 proteins that directly interact with TORC1. These data provide an important resource for labs studying cell growth control and stress signaling, and demonstrate the utility of our new, and easily adaptable, method for mapping gene regulatory networks.

  19. Identification of bovine leukemia virus tax function associated with host cell transcription, signaling, stress response and immune response pathway by microarray-based gene expression analysis

    Directory of Open Access Journals (Sweden)

    Arainga Mariluz

    2012-03-01

    Full Text Available Abstract Background Bovine leukemia virus (BLV is associated with enzootic bovine leukosis and is closely related to human T-cell leukemia virus type I. The Tax protein of BLV is a transcriptional activator of viral replication and a key contributor to oncogenic potential. We previously identified interesting mutant forms of Tax with elevated (TaxD247G or reduced (TaxS240P transactivation effects on BLV replication and propagation. However, the effects of these mutations on functions other than transcriptional activation are unknown. In this study, to identify genes that play a role in the cascade of signal events regulated by wild-type and mutant Tax proteins, we used a large-scale host cell gene-profiling approach. Results Using a microarray containing approximately 18,400 human mRNA transcripts, we found several alterations after the expression of Tax proteins in genes involved in many cellular functions such as transcription, signal transduction, cell growth, apoptosis, stress response, and immune response, indicating that Tax protein has multiple biological effects on various cellular environments. We also found that TaxD247G strongly regulated more genes involved in transcription, signal transduction, and cell growth functions, contrary to TaxS240P, which regulated fewer genes. In addition, the expression of genes related to stress response significantly increased in the presence of TaxS240P as compared to wild-type Tax and TaxD247G. By contrast, the largest group of downregulated genes was related to immune response, and the majority of these genes belonged to the interferon family. However, no significant difference in the expression level of downregulated genes was observed among the Tax proteins. Finally, the expression of important cellular factors obtained from the human microarray results were validated at the RNA and protein levels by real-time quantitative reverse transcription-polymerase chain reaction and western blotting

  20. Morphing structures and signal transduction in Mimosa pudica L. induced by localized thermal stress.

    Science.gov (United States)

    Volkov, Alexander G; O'Neal, Lawrence; Volkova, Maia I; Markin, Vladislav S

    2013-10-15

    Leaf movements in Mimosa pudica, are in response to thermal stress, touch, and light or darkness, appear to be regulated by electrical, hydrodynamical, and chemical signal transduction. The pulvinus of the M. pudica shows elastic properties. We have found that the movements of the petiole, or pinnules, are accompanied by a change of the pulvinus morphing structures. After brief flaming of a pinna, the volume of the lower part of the pulvinus decreases and the volume of the upper part increases due to the redistribution of electrolytes between these parts of the pulvinus; as a result of these changes the petiole falls. During the relaxation of the petiole, the process goes in the opposite direction. Ion and water channel blockers, uncouplers as well as anesthetic agents diethyl ether or chloroform decrease the speed of alert wave propagation along the plant. Brief flaming of a pinna induces bidirectional propagation of electrical signal in pulvini. Transduction of electrical signals along a pulvinus induces generation of an action potential in perpendicular direction between extensor and flexor sides of a pulvinus. Inhibition of signal transduction and mechanical responses in M. pudica by volatile anesthetic agents chloroform or by blockers of voltage gated ion channels shows that the generation and propagation of electrical signals is a primary effect responsible for turgor change and propagation of an excitation. There is an electrical coupling in a pulvinus similar to the electrical synapse in the animal nerves. Copyright © 2013 Elsevier GmbH. All rights reserved.

  1. Urm1: an essential regulator of JNK signaling and oxidative stress in Drosophila melanogaster.

    Science.gov (United States)

    Khoshnood, B; Dacklin, I; Grabbe, C

    2016-05-01

    Ubiquitin-related modifier 1 (Urm1) is a ubiquitin-like molecule (UBL) with the dual capacity to act both as a sulphur carrier and posttranslational protein modifier. Here we characterize the Drosophila melanogaster homologues of Urm1 (CG33276) and its E1 activating enzyme Uba4 (CG13090), and show that they function together to induce protein urmylation in vivo. Urm1 conjugation to target proteins in general, and to the evolutionary conserved substrate Peroxiredoxin 5 (Prx5) specifically, is dependent on Uba4. A complete loss of Urm1 is lethal in flies, although a small number of adult zygotic Urm1 (n123) mutant escapers can be recovered. These escapers display a decreased general fitness and shortened lifespan, but in contrast to their S. cerevisiae counterparts, they are resistant to oxidative stress. Providing a molecular explanation, we demonstrate that cytoprotective JNK signaling is increased in Urm1 deficient animals. In agreement, molecular and genetic evidence suggest that elevated activity of the JNK downstream target genes Jafrac1 and gstD1 strongly contributes to the tolerance against oxidative stress displayed by Urm1 (n123) null mutants. In conclusion, Urm1 is a UBL that is involved in the regulation of JNK signaling and the response against oxidative stress in the fruit fly.

  2. p38α controls erythroblast enucleation and Rb signaling in stress erythropoiesis

    Institute of Scientific and Technical Information of China (English)

    Simon M Schultze; Andreas Mairhofer; Dan Li; Jin Cen; Hartmut Beug; Erwin F Wagner; Lijian Hui

    2012-01-01

    Enucleation of erythroblasts during terminal differentiation is unique to mammals.Although erythroid enucleation has been extensively studied,only a few genes,including retinoblastoma protein(Rb),have been identified to regulate nuclear extrusion.It remains largely undefined by which signaling molecules,the extrinsic stimuli,such as erythropoietin(Epo),are transduced to induce enucleation.Here,we show that p38α,a mitogen-activated protein kinase(MAPK),is required for erythroid enucleation.In an ex vivo differentiation system that contains high Epo levels and mimics stress erythropoiesis,p38α is activated during erythroid differentiation.Loss of p38α completely blocks enucleation of primary erythroblasts.Moreover,p38α regulates erythroblast enucleation in a cell-autonomous manner in vivo during fetal and anemic stress erythropoiesis.Markedly,loss of p38α leads to downregulation of p21,and decreased activation of the p21 target Rb,both of which are important regulators of erythroblast enucleation.This study demonstrates that p38α is a key signaling molecule for erythroblast enucleation during stress erythropoiesis.

  3. Activation of stress signalling pathways enhances tolerance of fungi to chemical fungicides and antifungal proteins.

    Science.gov (United States)

    Hayes, Brigitte M E; Anderson, Marilyn A; Traven, Ana; van der Weerden, Nicole L; Bleackley, Mark R

    2014-07-01

    Fungal disease is an increasing problem in both agriculture and human health. Treatment of human fungal disease involves the use of chemical fungicides, which generally target the integrity of the fungal plasma membrane or cell wall. Chemical fungicides used for the treatment of plant disease, have more diverse mechanisms of action including inhibition of sterol biosynthesis, microtubule assembly and the mitochondrial respiratory chain. However, these treatments have limitations, including toxicity and the emergence of resistance. This has led to increased interest in the use of antimicrobial peptides for the treatment of fungal disease in both plants and humans. Antimicrobial peptides are a diverse group of molecules with differing mechanisms of action, many of which remain poorly understood. Furthermore, it is becoming increasingly apparent that stress response pathways are involved in the tolerance of fungi to both chemical fungicides and antimicrobial peptides. These signalling pathways such as the cell wall integrity and high-osmolarity glycerol pathway are triggered by stimuli, such as cell wall instability, changes in osmolarity and production of reactive oxygen species. Here we review stress signalling induced by treatment of fungi with chemical fungicides and antifungal peptides. Study of these pathways gives insight into how these molecules exert their antifungal effect and also into the mechanisms used by fungi to tolerate sub-lethal treatment by these molecules. Inactivation of stress response pathways represents a potential method of increasing the efficacy of antifungal molecules.

  4. A membrane-bound NAC transcription factor as an integrator of biotic and abiotic stress signals.

    Science.gov (United States)

    Seo, Pil Joon; Park, Chung-Mo

    2010-05-01

    Transcription factors are central components of gene regulatory networks that mediate virtually all aspects of growth and developmental processes in biological systems. The activity of transcription factors is regulated at multiple steps, such as gene transcription, posttranscriptional RNA processing, posttranslational modification, protein-protein interactions, and controlled protein turnover. Controlled activation of dormant, membrane-bound transcription factor (MTF) is an intriguing regulatory mechanism that ensures quick transcriptional responses to environmental fluctuations in plants, in which various stress hormones serve as signaling mediators. NTL6 is proteolytically activated upon exposure to cold and induces expression of the Pathogenesis-Related (PR) genes. The membrane-mediated cold signaling in inducing pathogen resistance is considered to be an adaptive strategy that protects plants against infection by hydrophilic pathogens frequently occurring during cold season. We found that NTL6 also mediates abscisic acid (ABA) regulation of abiotic stress responses in Arabidopsis. NTL6 is proteolytically activated by ABA. Transgenic plants overexpressing a nuclear NTL6 form (35S:6ΔC) exhibited a hypersensitive response to ABA and high salinity in seed germination. Taken together, these observations indicate that NTL6 plays an integrative role in plant responses to both biotic and abiotic stress conditions.

  5. Integrin-dependent activation of the JNK signaling pathway by mechanical stress.

    Directory of Open Access Journals (Sweden)

    Andrea Maria Pereira

    Full Text Available Mechanical force is known to modulate the activity of the Jun N-terminal kinase (JNK signaling cascade. However, the effect of mechanical stresses on JNK signaling activation has previously only been analyzed by in vitro detection methods. It still remains unknown how living cells activate the JNK signaling cascade in response to mechanical stress and what its functions are in stretched cells.We assessed in real-time the activity of the JNK pathway in Drosophila cells by Fluorescence Lifetime Imaging Microscopy (FLIM, using an intramolecular phosphorylation-dependent dJun-FRET (Fluorescence Resonance Energy Transfer biosensor. We found that quantitative FRET-FLIM analysis and confocal microscopy revealed sustained dJun-FRET biosensor activation and stable morphology changes in response to mechanical stretch for Drosophila S2R+ cells. Further, these cells plated on different substrates showed distinct levels of JNK activity that associate with differences in cell morphology, integrin expression and focal adhesion organization.These data imply that alterations in the cytoskeleton and matrix attachments may act as regulators of JNK signaling, and that JNK activity might feed back to modulate the cytoskeleton and cell adhesion. We found that this dynamic system is highly plastic; at rest, integrins at focal adhesions and talin are key factors suppressing JNK activity, while multidirectional static stretch leads to integrin-dependent, and probably talin-independent, Jun sensor activation. Further, our data suggest that JNK activity has to coordinate with other signaling elements for the regulation of the cytoskeleton and cell shape remodeling associated with stretch.

  6. Science Signaling Podcast for 28 February 2017: Balancing autophagy in the stressed heart.

    Science.gov (United States)

    Das, Saumya; VanHook, Annalisa M

    2017-02-28

    This Podcast features an interview with Saumya Das, senior author of a Research Article that appears in the 28 February 2017 issue of Science Signaling, about a protein that inhibits pathological cardiac hypertrophy in mice. Temporary increases in cardiac workload, such as those caused by exercise or pregnancy, induce physiological cardiac hypertrophy, a beneficial type of heart enlargement that is adaptive. However, a sustained increase in workload due to metabolic stress or uncontrolled high blood pressure induces pathological cardiac hypertrophy, which can contribute to heart failure. Simonson et al found that expression of DNA-damage-inducible transcript 4-like (DDiT4L) increased during pathological hypertrophy, but not during physiological hypertrophy, in mice. DDiT4L promoted stress-induced autophagy in cardiomyocytes by inhibiting signaling through the mechanistic target of rapamycin complex 1 (mTORC1) and stimulating signaling through mTORC2. These findings suggest that targeting autophagy, which is important for cellular homeostasis but can be detrimental in excess, may be useful for treating some cardiovascular diseases.Listen to Podcast. Copyright © 2017, American Association for the Advancement of Science.

  7. Stress-activated signaling responses leading to apoptosis following photodynamic therapy

    Science.gov (United States)

    Oleinick, Nancy L.; He, Jin; Xue, Liang-yan; Separovic, Duska

    1998-05-01

    Photodynamic treatment with the phthalocyanine Pc 4, a mitochondrially localizing photosensitizer, is an efficient inducer of cell death by apoptosis, a cell suicide pathway that can be triggered by physiological stimuli as well as by various types of cellular damage. Upon exposure of the dye- loaded cells to red light, several stress signalling pathways are rapidly activated. In murine L5178Y-R lymphoblasts, caspase activation and other hallmarks of the final phase of apoptosis are observed within a few minutes post-PDT. In Chinese hamster CHO-K1 cells, the first signs of apoptosis are not observed for 1 - 2 hours. The possible involvement of three parallel mitogen-activated protein kinase (MAPK) signalling pathways has been investigated. The extracellular- regulated kinases (ERK-1 and ERK-2), that are thought to promote cell growth, are not appreciably altered by PDT. However, PDT causes marked activation of the stress-activated protein kinase (SAPK) cascade in both cell types and of the p38/HOG-type kinase in CHO cells. Both of these latter pathways have been demonstrated to be associated with apoptosis. A specific inhibitor of the ERK pathway did not alter PDT-induced apoptosis; however, an inhibitor of the p38 pathway partially blocked PDT-induced apoptosis. Blockage of the SAPK pathway is being pursued by a genetic approach. It appears that the SAPK and p38 pathways may participate in signaling apoptosis in response to PDT with Pc 4.

  8. 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.

  9. Tart Cherry Extracts Reduce Inflammatory and Oxidative Stress Signaling in Microglial Cells.

    Science.gov (United States)

    Shukitt-Hale, Barbara; Kelly, Megan E; Bielinski, Donna F; Fisher, Derek R

    2016-09-22

    Tart cherries contain an array of polyphenols that can decrease inflammation and oxidative stress (OS), which contribute to cognitive declines seen in aging populations. Previous studies have shown that polyphenols from dark-colored fruits can reduce stress-mediated signaling in BV-2 mouse microglial cells, leading to decreases in nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression. Thus, the present study sought to determine if tart cherries-which improved cognitive behavior in aged rats-would be efficacious in reducing inflammatory and OS signaling in HAPI rat microglial cells. Cells were pretreated with different concentrations (0-1.0 mg/mL) of Montmorency tart cherry powder for 1-4 h, then treated with 0 or 100 ng/mL lipopolysaccharide (LPS) overnight. LPS application increased extracellular levels of NO and tumor necrosis factor-alpha (TNF-α), and intracellular levels of iNOS and cyclooxygenase-2 (COX-2). Pretreatment with tart cherry decreased levels of NO, TNF-α, and COX-2 in a dose- and time-dependent manner versus those without pretreatment; the optimal combination was between 0.125 and 0.25 mg/mL tart cherry for 2 h. Higher concentrations of tart cherry powder and longer exposure times negatively affected cell viability. Therefore, tart cherries (like other dark-colored fruits), may be effective in reducing inflammatory and OS-mediated signals.

  10. Tart Cherry Extracts Reduce Inflammatory and Oxidative Stress Signaling in Microglial Cells

    Directory of Open Access Journals (Sweden)

    Barbara Shukitt-Hale

    2016-09-01

    Full Text Available Tart cherries contain an array of polyphenols that can decrease inflammation and oxidative stress (OS, which contribute to cognitive declines seen in aging populations. Previous studies have shown that polyphenols from dark-colored fruits can reduce stress-mediated signaling in BV-2 mouse microglial cells, leading to decreases in nitric oxide (NO production and inducible nitric oxide synthase (iNOS expression. Thus, the present study sought to determine if tart cherries—which improved cognitive behavior in aged rats—would be efficacious in reducing inflammatory and OS signaling in HAPI rat microglial cells. Cells were pretreated with different concentrations (0–1.0 mg/mL of Montmorency tart cherry powder for 1–4 h, then treated with 0 or 100 ng/mL lipopolysaccharide (LPS overnight. LPS application increased extracellular levels of NO and tumor necrosis factor-alpha (TNF-α, and intracellular levels of iNOS and cyclooxygenase-2 (COX-2. Pretreatment with tart cherry decreased levels of NO, TNF-α, and COX-2 in a dose- and time-dependent manner versus those without pretreatment; the optimal combination was between 0.125 and 0.25 mg/mL tart cherry for 2 h. Higher concentrations of tart cherry powder and longer exposure times negatively affected cell viability. Therefore, tart cherries (like other dark-colored fruits, may be effective in reducing inflammatory and OS-mediated signals.

  11. Abscisic Acid Signaling and Abiotic Stress Tolerance in Plants: A Review on Current Knowledge and Future Prospects

    Science.gov (United States)

    Vishwakarma, Kanchan; Upadhyay, Neha; Kumar, Nitin; Yadav, Gaurav; Singh, Jaspreet; Mishra, Rohit K.; Kumar, Vivek; Verma, Rishi; Upadhyay, R. G.; Pandey, Mayank; Sharma, Shivesh

    2017-01-01

    Abiotic stress is one of the severe stresses of environment that lowers the growth and yield of any crop even on irrigated land throughout the world. A major phytohormone abscisic acid (ABA) plays an essential part in acting toward varied range of stresses like heavy metal stress, drought, thermal or heat stress, high level of salinity, low temperature, and radiation stress. Its role is also elaborated in various developmental processes including seed germination, seed dormancy, and closure of stomata. ABA acts by modifying the expression level of gene and subsequent analysis of cis- and trans-acting regulatory elements of responsive promoters. It also interacts with the signaling molecules of processes involved in stress response and development of seeds. On the whole, the stress to a plant can be susceptible or tolerant by taking into account the coordinated activities of various stress-responsive genes. Numbers of transcription factor are involved in regulating the expression of ABA responsive genes by acting together with their respective cis-acting elements. Hence, for improvement in stress-tolerance capacity of plants, it is necessary to understand the mechanism behind it. On this ground, this article enlightens the importance and role of ABA signaling with regard to various stresses as well as regulation of ABA biosynthetic pathway along with the transcription factors for stress tolerance. PMID:28265276

  12. The C-Terminal Domain of Chikungunya Virus nsP2 Independently Governs Viral RNA Replication, Cytopathicity, and Inhibition of Interferon Signaling

    OpenAIRE

    Fros, J. J.; van der Maten, E.; Vlak, J. M.; Pijlman, G.P.

    2013-01-01

    Alphavirus nonstructural protein 2 (nsP2) has pivotal roles in viral RNA replication, host cell shutoff, and inhibition of antiviral responses. Mutations that individually rendered other alphaviruses noncytopathic were introduced into chikungunya virus nsP2. Results show that (i) nsP2 mutation P718S only in combination with KR649AA or adaptive mutation D711G allowed noncytopathic replicon RNA replication, (ii) prohibiting nsP2 nuclear localization abrogates inhibition of antiviral interferon-...

  13. Neuropeptide Y (NPY): genetic variation in the human promoter alters glucocorticoid signaling, yielding increased NPY secretion and stress responses.

    Science.gov (United States)

    Zhang, Kuixing; Rao, Fangwen; Miramontes-Gonzalez, Jose Pablo; Hightower, C Makena; Vaught, Brian; Chen, Yuhong; Greenwood, Tiffany A; Schork, Andrew J; Wang, Lei; Mahata, Manjula; Stridsberg, Mats; Khandrika, Srikrishna; Biswas, Nilima; Fung, Maple M; Waalen, Jill; Middelberg, Rita P; Heath, Andrew C; Montgomery, Grant W; Martin, Nicholas G; Whitfield, John B; Baker, Dewleen G; Schork, Nicholas J; Nievergelt, Caroline M; O'Connor, Daniel T

    2012-10-23

    This study sought to understand whether genetic variation at the Neuropeptide Y (NPY) locus governs secretion and stress responses in vivo as well as NPY gene expression in sympathochromaffin cells. The NPY is a potent pressor peptide co-released with catecholamines during stress by sympathetic axons. Genome-wide linkage on NPY secretion identified a LOD (logarithm of the odds ratio) peak spanning the NPY locus on chromosome 7p15. Our approach began with genomics (linkage and polymorphism determination), extended into NPY genetic control of heritable stress traits in twin pairs, established transcriptional mechanisms in transfected chromaffin cells, and concluded with observations on blood pressure (BP) in the population. Systematic polymorphism tabulation at NPY (by re-sequencing across the locus: promoter, 4 exons, exon/intron borders, and untranslated regions; on 2n = 160 chromosomes of diverse biogeographic ancestries) identified 16 variants, of which 5 were common. We then studied healthy twin/sibling pairs (n = 399 individuals), typing 6 polymorphisms spanning the locus. Haplotype and single nucleotide polymorphism analyses indicated that proximal promoter variant ∇-880Δ (2-bp TG/-, Ins/Del, rs3037354) minor/Δ allele was associated with several heritable (h(2)) stress traits: higher NPY secretion (h(2) = 73 ± 4%) as well as greater BP response to environmental (cold) stress, and higher basal systemic vascular resistance. Association of ∇-880Δ and plasma NPY was replicated in an independent sample of 361 healthy young men, with consistent allelic effects; genetic variation at NPY also associated with plasma NPY in another independent series of 2,212 individuals derived from Australia twin pairs. Effects of allele -880Δ to increase NPY expression were directionally coordinate in vivo (on human traits) and in cells (transfected NPY promoter/luciferase reporter activity). Promoter -880Δ interrupts a novel glucocorticoid response element motif, an effect

  14. Stress-responsive sestrins link p53 with redox regulation and mammalian target of rapamycin signaling.

    Science.gov (United States)

    Budanov, Andrei V

    2011-09-15

    The tumor suppressor p53 protects organisms from most types of cancer through multiple mechanisms. The p53 gene encodes a stress-activated transcriptional factor that transcriptionally regulates a large set of genes with versatile functions. These p53-activated genes mitigate consequences of stress regulating cell viability, growth, proliferation, repair, and metabolism. Recently, we described a novel antioxidant function of p53, which is important for its tumor suppressor activity. Among the many antioxidant genes activated by p53, Sestrins (Sesns) are critical for suppression of reactive oxygen species (ROS) and protection from oxidative stress, transformation, and genomic instability. Sestrins can regulate ROS through their direct effect on antioxidant peroxiredoxin proteins and through the AMP-activated protein kinase-target of rapamycin signaling pathway. The AMP-activated protein kinase-target of rapamycin axis is critical for regulation of metabolism and autophagy, two processes associated with ROS production, and deregulation of this pathway increases vulnerability of the organism to stress, aging, and age-related diseases, including cancer. Recently, we have shown that inactivation of Sestrin in fly causes accumulation of age-associated damage. Hence, Sestrins can link p53 with aging and age-related diseases.

  15. Chemistry and biology of reactive oxygen species in signaling or stress responses.

    Science.gov (United States)

    Dickinson, Bryan C; Chang, Christopher J

    2011-07-18

    Reactive oxygen species (ROS) are a family of molecules that are continuously generated, transformed and consumed in all living organisms as a consequence of aerobic life. The traditional view of these reactive oxygen metabolites is one of oxidative stress and damage that leads to decline of tissue and organ systems in aging and disease. However, emerging data show that ROS produced in certain situations can also contribute to physiology and increased fitness. This Perspective provides a focused discussion on what factors lead ROS molecules to become signal and/or stress agents, highlighting how increasing knowledge of the underlying chemistry of ROS can lead to advances in understanding their disparate contributions to biology. An important facet of this emerging area at the chemistry-biology interface is the development of new tools to study these small molecules and their reactivity in complex biological systems.

  16. Electric signal emissions during repeated abrupt uniaxial compressional stress steps in amphibolite from KTB drilling

    Directory of Open Access Journals (Sweden)

    D. Triantis

    2007-01-01

    Full Text Available Laboratory experiments have confirmed that the application of uniaxial stress on rock samples is accompanied by the production of weak electric currents, to which the term Pressure Stimulated Currents – PSC has been attributed. In this work the PSC emissions in amphibolite samples from KTB drilling are presented and commented upon. After having applied sequential loading and unloading cycles on the amphibolite samples, it was ascertained that in every new loading cycle after unloading, the emitted PSC exhibits lower peaks. This attitude of the current peaks is consistent with the acoustic emissions phenomena, and in this work is verified for PSC emissions during loading – unloading procedures. Consequently, the evaluation of such signals can help to correlate the state and the remaining strength of the sample with respect to the history of its mechanical stress.

  17. Mechanistic Basis for Plant Responses to Drought Stress : Regulatory Mechanism of Abscisic Acid Signaling

    Science.gov (United States)

    Miyakawa, Takuya; Tanokura, Masaru

    The phytohormone abscisic acid (ABA) plays a key role in the rapid adaptation of plants to environmental stresses such as drought and high salinity. Accumulated ABA in plant cells promotes stomatal closure in guard cells and transcription of stress-tolerant genes. Our understanding of ABA responses dramatically improved by the discovery of both PYR/PYL/RCAR as a soluble ABA receptor and inhibitory complex of a protein phospatase PP2C and a protein kinase SnRK2. Moreover, several structural analyses of PYR/PYL/RCAR revealed the mechanistic basis for the regulatory mechanism of ABA signaling, which provides a rational framework for the design of alternative agonists in future.

  18. Yeast as a Tool to Study Signaling Pathways in Mitochondrial Stress Response and Cytoprotection

    Directory of Open Access Journals (Sweden)

    Maša Ždralević

    2012-01-01

    Full Text Available Cell homeostasis results from the balance between cell capability to adapt or succumb to environmental stress. Mitochondria, in addition to supplying cellular energy, are involved in a range of processes deciding about cellular life or death. The crucial role of mitochondria in cell death is well recognized. Mitochondrial dysfunction has been associated with the death process and the onset of numerous diseases. Yet, mitochondrial involvement in cellular adaptation to stress is still largely unexplored. Strong interest exists in pharmacological manipulation of mitochondrial metabolism and signaling. The yeast Saccharomyces cerevisiae has proven a valuable model organism in which several intracellular processes have been characterized in great detail, including the retrograde response to mitochondrial dysfunction and, more recently, programmed cell death. In this paper we review experimental evidences of mitochondrial involvement in cytoprotection and propose yeast as a model system to investigate the role of mitochondria in the cross-talk between prosurvival and prodeath pathways.

  19. MicroRNAs in the Stressed Heart: Sorting the Signal from the Noise

    Directory of Open Access Journals (Sweden)

    Scot J. Matkovich

    2014-08-01

    Full Text Available The short noncoding RNAs, known as microRNAs, are of undisputed importance in cellular signaling during differentiation and development, and during adaptive and maladaptive responses of adult tissues, including those that comprise the heart. Cardiac microRNAs are regulated by hemodynamic overload resulting from exercise or hypertension, in the response of surviving myocardium to myocardial infarction, and in response to environmental or systemic disruptions to homeostasis, such as those arising from diabetes. A large body of work has explored microRNA responses in both physiological and pathological contexts but there is still much to learn about their integrated actions on individual mRNAs and signaling pathways. This review will highlight key studies of microRNA regulation in cardiac stress and suggest possible approaches for more precise identification of microRNA targets, with a view to exploiting the resulting data for therapeutic purposes.

  20. Epigenetic Deficiencies and Replicative Stress

    DEFF Research Database (Denmark)

    Shoaib, Muhammad; Sørensen, Claus Storgaard

    2015-01-01

    Cancer cell-specific synthetic lethal interactions entail promising therapeutic possibilities. In this issue of Cancer Cell, Pfister et al. describe a synthetic lethal interaction where cancer cells deficient in H3K36me3 owing to SETD2 loss-of-function mutation are strongly sensitized to inhibiti...

  1. LHCb experience with LFC replication

    CERN Document Server

    Bonifazi, F; Perez, E D; D'Apice, A; dell'Agnello, L; Düllmann, D; Girone, M; Re, G L; Martelli, B; Peco, G; Ricci, P P; Sapunenko, V; Vagnoni, V; Vitlacil, D

    2008-01-01

    Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. a database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informatics (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements.

  2. LHCb experience with LFC replication

    CERN Document Server

    Carbone, Angelo; Dafonte Perez, Eva; D'Apice, Antimo; dell'Agnello, Luca; Duellmann, Dirk; Girone, Maria; Lo Re, Giuseppe; Martelli, Barbara; Peco, Gianluca; Ricci, Pier Paolo; Sapunenko, Vladimir; Vagnoni, Vincenzo; Vitlacil, Dejan

    2007-01-01

    Database replication is a key topic in the framework of the LHC Computing Grid to allow processing of data in a distributed environment. In particular, the LHCb computing model relies on the LHC File Catalog, i.e. database which stores information about files spread across the GRID, their logical names and the physical locations of all the replicas. The LHCb computing model requires the LFC to be replicated at Tier-1s. The LCG 3D project deals with the database replication issue and provides a replication service based on Oracle Streams technology. This paper describes the deployment of the LHC File Catalog replication to the INFN National Center for Telematics and Informations (CNAF) and to other LHCb Tier-1 sites. We performed stress tests designed to evaluate any delay in the propagation of the streams and the scalability of the system. The tests show the robustness of the replica implementation with performance going much beyond the LHCb requirements.

  3. Fluid shear stress inhibits TNF-α-induced osteoblast apoptosis via ERK5 signaling pathway.

    Science.gov (United States)

    Bin, Geng; Cuifang, Wang; Bo, Zhang; Jing, Wang; Jin, Jiang; Xiaoyi, Tan; Cong, Chen; Yonggang, Chen; Liping, An; Jinglin, Ma; Yayi, Xia

    2015-10-09

    Fluid shear stress (FSS) is a potent mechanical stimulus and prevents cells from TNF-a-induced apoptosis. Recently, Extracellular-signal-regulated kinase 5 (ERK5) has been found to be involved in regulation of cell survival. However, little is known about the role of ERK5 signaling pathway in FSS-mediated anti-apoptotic effects in osteoblast. In this study, we show that FSS blocks TNF-a-induced apoptosis of MC3T3-E1 cells via ERK5 signaling pathway. We found that physiological FSS for 1 h significantly decreased TNF-α-induced MC3T3-E1 cells apoptosis. After inhibition of ERK5 activity by XMD8-92, a highly-selective inhibitor of ERK5 activity, the ability of FSS to inhibit TNF-α induced apoptosis was significantly decreased. Analysis of anti-apoptotic mechanisms indicated that exposure of MC3T3-E1 cells to FSS for 1 h increased phosphorylation of Bad and inhibited caspase-3 activity. After treatment with XMD8-92, phosphorylation of Bad by FSS was significantly blocked, but caspase-3 activity was increased. In summary, these findings indicated that FSS inhibits TNF-α-mediated signaling events in osteoblast by a mechanism dependent on activation of ERK5, and Bad is a crucial downstream target for ERK5. Those results implied that ERK5 signaling pathway play a crucial role in FSS-mediated anti-apoptotic effect in osteoblast. Thus, ERK5 signaling pathway may be a new drug treatment target of osteoporosis and related bone-wasting diseases.

  4. Periostin responds to mechanical stress and tension by activating the MTOR signaling pathway.

    Directory of Open Access Journals (Sweden)

    Luciana K Rosselli-Murai

    Full Text Available Current knowledge about Periostin biology has expanded from its recognized functions in embryogenesis and bone metabolism to its roles in tissue repair and remodeling and its clinical implications in cancer. Emerging evidence suggests that Periostin plays a critical role in the mechanism of wound healing; however, the paracrine effect of Periostin in epithelial cell biology is still poorly understood. We found that epithelial cells are capable of producing endogenous Periostin that, unlike mesenchymal cell, cannot be secreted. Epithelial cells responded to Periostin paracrine stimuli by enhancing cellular migration and proliferation and by activating the mTOR signaling pathway. Interestingly, biomechanical stimulation of epithelial cells, which simulates tension forces that occur during initial steps of tissue healing, induced Periostin production and mTOR activation. The molecular association of Periostin and mTOR signaling was further dissected by administering rapamycin, a selective pharmacological inhibitor of mTOR, and by disruption of Raptor and Rictor scaffold proteins implicated in the regulation of mTORC1 and mTORC2 complex assembly. Both strategies resulted in ablation of Periostin-induced mitogenic and migratory activity. These results indicate that Periostin-induced epithelial migration and proliferation requires mTOR signaling. Collectively, our findings identify Periostin as a mechanical stress responsive molecule that is primarily secreted by fibroblasts during wound healing and expressed endogenously in epithelial cells resulting in the control of cellular physiology through a mechanism mediated by the mTOR signaling cascade.

  5. Metabotropic glutamate receptor-mediated signaling dampens the HPA axis response to restraint stress.

    Science.gov (United States)

    Evanson, Nathan K; Herman, James P

    2015-10-15

    Glutamate is an important neurotransmitter in the regulation of the neural portion of hypothalamus-pituitary-adrenal (HPA) axis activity, and signals through ionotropic and metabotropic receptors. In the current studies we investigated the role of hypothalamic paraventricular group I metabotropic glutamate receptors in the regulation of the HPA axis response to restraint stress in rats. Direct injection of the group I metabotropic glutamate receptor agonist 3,5-dihydroxyphenylglycine (DHPG) into the PVN prior to restraint leads to blunting of the HPA axis response in awake animals. Consistent with this result, infusion of the group I receptor antagonist hexyl-homoibotenic acid (HIBO) potentiates the HPA axis response to restraint. The excitatory effect of blocking paraventricular group I metabotropic glutamate signaling is blocked by co-administration of dexamethasone into the PVN. However, the inhibitory effect of DHPG is not affected by co-administration of the cannabinoid CB1 receptor antagonist AM-251 into the PVN. Together, these results suggest that paraventricular group I metabotropic glutamate receptor signaling acts to dampen HPA axis reactivity. This effect appears to be similar to the rapid inhibitory effect of glucocorticoids at the PVN, but is not mediated by endocannabinoid signaling.

  6. Apoplastic reactive oxygen species transiently decrease auxin signaling and cause stress-induced morphogenic response in Arabidopsis.

    Science.gov (United States)

    Blomster, Tiina; Salojärvi, Jarkko; Sipari, Nina; Brosché, Mikael; Ahlfors, Reetta; Keinänen, Markku; Overmyer, Kirk; Kangasjärvi, Jaakko

    2011-12-01

    Reactive oxygen species (ROS) are ubiquitous signaling molecules in plant stress and development. To gain further insight into the plant transcriptional response to apoplastic ROS, the phytotoxic atmospheric pollutant ozone was used as a model ROS inducer in Arabidopsis (Arabidopsis thaliana) and gene expression was analyzed with microarrays. In contrast to the increase in signaling via the stress hormones salicylic acid, abscisic acid, jasmonic acid (JA), and ethylene, ROS treatment caused auxin signaling to be transiently suppressed, which was confirmed with a DR5-uidA auxin reporter construct. Transcriptomic data revealed that various aspects of auxin homeostasis and signaling were modified by apoplastic ROS. Furthermore, a detailed analysis of auxin signaling showed that transcripts of several auxin receptors and Auxin/Indole-3-Acetic Acid (Aux/IAA) transcriptional repressors were reduced in response to apoplastic ROS. The ROS-derived changes in the expression of auxin signaling genes partially overlapped with abiotic stress, pathogen responses, and salicylic acid signaling. Several mechanisms known to suppress auxin signaling during biotic stress were excluded, indicating that ROS regulated auxin responses via a novel mechanism. Using mutants defective in various auxin (axr1, nit1, aux1, tir1 afb2, iaa28-1, iaa28-2) and JA (axr1, coi1-16) responses, ROS-induced cell death was found to be regulated by JA but not by auxin. Chronic ROS treatment resulted in altered leaf morphology, a stress response known as "stress-induced morphogenic response." Altered leaf shape of tir1 afb2 suggests that auxin was a negative regulator of stress-induced morphogenic response in the rosette.

  7. A new branch of endoplasmic reticulum stress signaling and the osmotic signal converge on plant-specific asparagine-rich proteins to promote cell death.

    Science.gov (United States)

    Costa, Maximiller D L; Reis, Pedro A B; Valente, Maria Anete S; Irsigler, André S T; Carvalho, Claudine M; Loureiro, Marcelo E; Aragão, Francisco J L; Boston, Rebecca S; Fietto, Luciano G; Fontes, Elizabeth P B

    2008-07-18

    NRPs (N-rich proteins) were identified as targets of a novel adaptive pathway that integrates endoplasmic reticulum (ER) and osmotic stress signals based on coordinate regulation and synergistic up-regulation by tunicamycin and polyethylene glycol treatments. This integrated pathway diverges from the molecular chaperone-inducing branch of the unfolded protein response (UPR) in several ways. While UPR-specific targets were inversely regulated by ER and osmotic stresses, NRPs required both signals for full activation. Furthermore, BiP (binding protein) overexpression in soybean prevented activation of the UPR by ER stress inducers, but did not affect activation of NRPs. We also found that this integrated pathway transduces a PCD signal generated by ER and osmotic stresses that result in the appearance of markers associated with leaf senescence. Overexpression of NRPs in soybean protoplasts induced caspase-3-like activity and promoted extensive DNA fragmentation. Furthermore, transient expression of NRPs in planta caused leaf yellowing, chlorophyll loss, malondialdehyde production, ethylene evolution, and induction of the senescence marker gene CP1. This phenotype was alleviated by the cytokinin zeatin, a potent senescence inhibitor. Collectively, these results indicate that ER stress induces leaf senescence through activation of plant-specific NRPs via a novel branch of the ER stress response.

  8. Disease Progression Mediated by Egr-1 Associated Signaling in Response to Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Elisabeth Deindl

    2012-10-01

    Full Text Available When cellular reducing enzymes fail to shield the cell from increased amounts of reactive oxygen species (ROS, oxidative stress arises. The redox state is misbalanced, DNA and proteins are damaged and cellular transcription networks are activated. This condition can lead to the initiation and/or to the progression of atherosclerosis, tumors or pulmonary hypertension; diseases that are decisively furthered by the presence of oxidizing agents. Redox sensitive genes, like the zinc finger transcription factor early growth response 1 (Egr-1, play a pivotal role in the pathophysiology of these diseases. Apart from inducing apoptosis, signaling partners like the MEK/ERK pathway or the protein kinase C (PKC can activate salvage programs such as cell proliferation that do not ameliorate, but rather worsen their outcome. Here, we review the currently available data on Egr-1 related signal transduction cascades in response to oxidative stress in the progression of epidemiologically significant diseases. Knowing the molecular pathways behind the pathology will greatly enhance our ability to identify possible targets for the development of new therapeutic strategies.

  9. Orexins protect neuronal cell cultures against hypoxic stress: an involvement of Akt signaling.

    Science.gov (United States)

    Sokołowska, Paulina; Urbańska, Anna; Biegańska, Kaja; Wagner, Waldemar; Ciszewski, Wojciech; Namiecińska, Magdalena; Zawilska, Jolanta B

    2014-01-01

    Orexins A and B are peptides produced mainly by hypothalamic neurons that project to numerous brain structures. We have previously demonstrated that rat cortical neurons express both types of orexin receptors, and their activation by orexins initiates different intracellular signals. The present study aimed to determine the effect of orexins on the Akt kinase activation in the rat neuronal cultures and the significance of that response in neurons subjected to hypoxic stress. We report the first evidence that orexins A and B stimulated Akt in cortical neurons in a concentration- and time-dependent manner. Orexin B more potently than orexin A increased Akt phosphorylation, but the maximal effect of both peptides on the kinase activation was very similar. Next, cultured cortical neurons were challenged with cobalt chloride, an inducer of reactive oxygen species and hypoxia-mediated signaling pathways. Under conditions of chemical hypoxia, orexins potently increased neuronal viability and protected cortical neurons against oxidative stress. Our results also indicate that Akt kinase plays an important role in the pro-survival effects of orexins in neurons, which implies a possible mechanism of the orexin-induced neuroprotection.

  10. Life stress, glucocorticoid signaling, and the aging epigenome: Implications for aging-related diseases.

    Science.gov (United States)

    Gassen, Nils C; Chrousos, George P; Binder, Elisabeth B; Zannas, Anthony S

    2017-03-01

    Life stress has been associated with accelerated cellular aging and increased risk for developing aging-related diseases; however, the underlying molecular mechanisms remain elusive. A highly relevant process that may underlie this association is epigenetic regulation. In this review, we build upon existing evidence to propose a model whereby exposure to life stress, in part via its effects on the hypothalamic-pituitary axis and the glucocorticoid signaling system, may alter the epigenetic landscape across the lifespan and, consequently, influence genomic regulation and function in ways that are conducive to the development of aging-related diseases. This model is supported by recent studies showing that life stressors and stress-related phenotypes can accelerate epigenetic aging, a measure that is based on DNA methylation prediction of chronological age and has been associated with several aging-related disease phenotypes. We discuss the implications of this model for the prevention and treatment of aging-related diseases, as well as the challenges and limitations of this line of research.

  11. Slm35 links mitochondrial stress response and longevity through TOR signaling pathway

    Science.gov (United States)

    Jose, L. Aguilar-Lopez; Laboy, Raymond; Fabiola, Jaimes-Miranda; Garay, Erika; Alexander, DeLuna; Funes, Soledad

    2016-01-01

    In most eukaryotic cells mitochondria are essential organelles involved in a great variety of cellular functions. One of the physiological processes linked to mitochondria is aging, a gradual process of damage accumulation that eventually promotes cell death. Aging depends on a balance between mitochondrial biogenesis, function and degradation. It has been previously shown that Tor1, Sch9 and Ras2 are activated in response to nutrient availability and regulate cell growth and division. A deficiency in any of these genes promotes lifespan extension and cell protection during oxidative and heat shock stress. In this work we report that in Saccharomyces cerevisiae, the uncharacterized mitochondrial protein Slm35 is functionally linked with the TOR signaling pathway. A Δtor1Δslm35 strain shows a severe decrease in lifespan and is unable to contend with oxidative and heat shock stresses. Specifically, this mutant shows decreased catalase activity indicating a misregulation of ROS scavenging mechanisms. In this study we show that Slm35 is also relevant for mitochondrial network dynamics and mitophagy. The results presented here suggest that Slm35 plays an important role connecting mitochondrial function with cytosolic responses and cell adaptation to stress and aging. PMID:27922823

  12. Cellular stress stimulates nuclear localization signal (NLS) independent nuclear transport of MRJ

    Science.gov (United States)

    Andrews, Joel F.; Sykora, Landon J.; Barik-Letostak, Tiasha; Menezes, Mitchell E.; Mitra, Aparna; Barik, Sailen; Shevde, Lalita A.; Samant, Rajeev S.

    2012-01-01

    HSP40 family member MRJ (DNAJB6) has been in the spot light for its relevance to Huntington’s, Parkinson’s diseases, limb-girdle muscular dystrophy, placental development, neural stem cells, cell cycle and malignancies such as breast cancer and melanoma. This gene has two spliced variants coding for 2 distinct proteins with significant homology. However, MRJ(L) (large variant) is predominantly localized to the nucleus whereas MRJ(S) (small variant) is predominantly cytoplasmic. Interestingly MRJ(S) translocates to the nucleus in response to heat shock. The classical heat shock proteins respond to crises (stress) by increasing the number of molecules, usually by transcriptional up-regulation. Our studies imply that a quick increase in the molar concentration of MRJ in the nuclear compartment is a novel method by which MRJ responds to stress. We found that MRJ(S) shows NLS (nuclear localization signal) independent nuclear localization in response to heat shock and hypoxia. The specificity of this response is realized due to lack of such response by MRJ(S) when challenged by other stressors, such as some cytokines or UV light. Deletion analysis has allowed us to narrow down on a 20 amino acid stretch at the C-terminal region of MRJ(S) as a potential stress sensing region. Functional studies indicated that constitutive nuclear localization of MRJ(S) promoted attributes of malignancy such as proliferation and invasiveness overall indicating distinct phenotypic characteristics of nuclear MRJ(S). PMID:22504047

  13. Cellular stress stimulates nuclear localization signal (NLS) independent nuclear transport of MRJ

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Joel F.; Sykora, Landon J.; Barik Letostak, Tiasha; Menezes, Mitchell E.; Mitra, Aparna [Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL (United States); Barik, Sailen [Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science, Cleveland State University, Cleveland, OH (United States); Shevde, Lalita A. [Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL (United States); Samant, Rajeev S., E-mail: rsamant@usouthal.edu [Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL (United States)

    2012-06-10

    HSP40 family member MRJ (DNAJB6) has been in the spot light for its relevance to Huntington's, Parkinson's diseases, limb-girdle muscular dystrophy, placental development, neural stem cells, cell cycle and malignancies such as breast cancer and melanoma. This gene has two spliced variants coding for 2 distinct proteins with significant homology. However, MRJ(L) (large variant) is predominantly localized to the nucleus whereas MRJ(S) (small variant) is predominantly cytoplasmic. Interestingly MRJ(S) translocates to the nucleus in response to heat shock. The classical heat shock proteins respond to crises (stress) by increasing the number of molecules, usually by transcriptional up-regulation. Our studies imply that a quick increase in the molar concentration of MRJ in the nuclear compartment is a novel method by which MRJ responds to stress. We found that MRJ(S) shows NLS (nuclear localization signal) independent nuclear localization in response to heat shock and hypoxia. The specificity of this response is realized due to lack of such response by MRJ(S) when challenged by other stressors, such as some cytokines or UV light. Deletion analysis has allowed us to narrow down on a 20 amino acid stretch at the C-terminal region of MRJ(S) as a potential stress sensing region. Functional studies indicated that constitutive nuclear localization of MRJ(S) promoted attributes of malignancy such as proliferation and invasiveness overall indicating distinct phenotypic characteristics of nuclear MRJ(S).

  14. Regulatory cross-talks and cascades in rice hormone biosynthesis pathways contribute to stress signaling

    Directory of Open Access Journals (Sweden)

    Arindam Deb

    2016-08-01

    Full Text Available Crosstalk among different hormone signaling pathways play an important role in modulating plant response to both biotic and abiotic stress. Hormone activity is controlled by its bio-availability, which is again influenced by its biosynthesis. Thus independent hormone biosynthesis pathways must be regulated and co-ordinated to mount an integrated response. One of the possibilities is to use cis-regulatory elements to orchestrate expression of hormone biosynthesis genes. Analysis of CREs, associated with differentially expressed hormone biosynthesis related genes in rice leaf under Magnaporthe oryzae attack and drought stress enabled us to obtain insights about cross-talk among hormone biosynthesis pathways at the transcriptional level. We identified some master transcription regulators that co-ordinate different hormone biosynthesis pathways under stress. We found that Abscisic acid and Brassinosteroid regulate Cytokinin conjugation; conversely Brassinosteroid biosynthesis is affected by both Abscisic acid and Cytokinin. Jasmonic acid and Ethylene biosynthesis may be modulated by Abscisic acid through DREB transcription factors. Jasmonic acid or Salicylic acid biosynthesis pathways are co-regulated but they are unlikely to influence each other’s production directly. Thus multiple hormones may modulate hormone biosynthesis pathways through a complex regulatory network, where biosynthesis of one hormone is affected by several other contributing hormones.

  15. Regulatory Cross-Talks and Cascades in Rice Hormone Biosynthesis Pathways Contribute to Stress Signaling.

    Science.gov (United States)

    Deb, Arindam; Grewal, Rumdeep K; Kundu, Sudip

    2016-01-01

    Crosstalk among different hormone signaling pathways play an important role in modulating plant response to both biotic and abiotic stress. Hormone activity is controlled by its bio-availability, which is again influenced by its biosynthesis. Thus, independent hormone biosynthesis pathways must be regulated and co-ordinated to mount an integrated response. One of the possibilities is to use cis-regulatory elements to orchestrate expression of hormone biosynthesis genes. Analysis of CREs, associated with differentially expressed hormone biosynthesis related genes in rice leaf under Magnaporthe oryzae attack and drought stress enabled us to obtain insights about cross-talk among hormone biosynthesis pathways at the transcriptional level. We identified some master transcription regulators that co-ordinate different hormone biosynthesis pathways under stress. We found that Abscisic acid and Brassinosteroid regulate Cytokinin conjugation; conversely Brassinosteroid biosynthesis is affected by both Abscisic acid and Cytokinin. Jasmonic acid and Ethylene biosynthesis may be modulated by Abscisic acid through DREB transcription factors. Jasmonic acid or Salicylic acid biosynthesis pathways are co-regulated but they are unlikely to influence each others production directly. Thus, multiple hormones may modulate hormone biosynthesis pathways through a complex regulatory network, where biosynthesis of one hormone is affected by several other contributing hormones.

  16. The effects of life stress and neural learning signals on fluid intelligence.

    Science.gov (United States)

    Friedel, Eva; Schlagenhauf, Florian; Beck, Anne; Dolan, Raymond J; Huys, Quentin J M; Rapp, Michael A; Heinz, Andreas

    2015-02-01

    Fluid intelligence (fluid IQ), defined as the capacity for rapid problem solving and behavioral adaptation, is known to be modulated by learning and experience. Both stressful life events (SLES) and neural correlates of learning [specifically, a key mediator of adaptive learning in the brain, namely the ventral striatal representation of prediction errors (PE)] have been shown to be associated with individual differences in fluid IQ. Here, we examine the interaction between adaptive learning signals (using a well-characterized probabilistic reversal learning task in combination with fMRI) and SLES on fluid IQ measures. We find that the correlation between ventral striatal BOLD PE and fluid IQ, which we have previously reported, is quantitatively modulated by the amount of reported SLES. Thus, after experiencing adversity, basic neuronal learning signatures appear to align more closely with a general measure of flexible learning (fluid IQ), a finding complementing studies on the effects of acute stress on learning. The results suggest that an understanding of the neurobiological correlates of trait variables like fluid IQ needs to take socioemotional influences such as chronic stress into account.

  17. Putrescine as a signal to modulate the indispensable ABA increase under cold stress

    Science.gov (United States)

    Cuevas, Juan C; López-Cobollo, Rosa; Alcázar, Rubén; Zarza, Xavier; Koncz, Csaba; Altabella, Teresa; Salinas, Julio; Tiburcio, Antonio F

    2009-01-01

    Polyamines have been found to correlate frequently with biotic and abiotic insults, and their functional involvement in the plant responses to several stresses has been shown genetically with both gain and loss of function mutations. In spite of a large body of physiological and genetic data, the mode of action for polyamines at the molecular level still remains elusive. We have recently performed a detailed integrated analysis of polyamine metabolism under cold stress by means of metabolic studies, quantitative gene expression analyses, and gene inactivations, to characterize in more detail the role of polyamines in response to low temperature. Our data show a unique accumulation profile for putrescine compared to other polyamines, with a progressive increase upon cold stress treatment coincident with a similar transcriptional upregulation for the two arginine decarboxylase genes ADC1 and ADC2. Loss of function mutants adc1 and adc2 display reduced freezing tolerance and alterations in ABA content and ABA-dependent signalling pathways under low temperature, compared to wild type plants. Phenotypical reverse complementation tests for both adc and ABA-defective mutants support our conclusion that putrescine modulates ABA biosynthesis at the transcriptional level in response to low temperature thus uncovering a novel mode of action for polyamines as regulators of hormone biosynthesis. PMID:19721755

  18. Chronic Psychosocial Stress and Negative Feedback Inhibition: Enhanced Hippocampal Glucocorticoid Signaling despite Lower Cytoplasmic GR Expression.

    Science.gov (United States)

    Füchsl, Andrea M; Reber, Stefan O

    2016-01-01

    Chronic subordinate colony housing (CSC), a pre-clinically validated mouse model for chronic psychosocial stress, results in increased basal and acute stress-induced plasma adrenocorticotropic hormone (ACTH) levels. We assessed CSC effects on hippocampal glucocorticoid (GC) receptor (GR), mineralocorticoid receptor (MR), and FK506 binding protein (FKBP51) expression, acute heterotypic stressor-induced GR translocation, as well as GC effects on gene expression and cell viability in isolated hippocampal cells. CSC mice showed decreased GR mRNA and cytoplasmic protein levels compared with single-housed control (SHC) mice. Basal and acute stress-induced nuclear GR protein expression were comparable between CSC and SHC mice, as were MR and FKBP51 mRNA and/or cytoplasmic protein levels. In vitro the effect of corticosterone (CORT) on hippocampal cell viability and gene transcription was more pronounced in CSC versus SHC mice. In summary, CSC mice show an, if at all, increased hippocampal GC signaling capacity despite lower cytoplasmic GR protein expression, making negative feedback deficits in the hippocampus unlikely to contribute to the increased ACTH drive following CSC.

  19. Inhibition of TGFbeta1 Signaling Attenutates ATM Activity inResponse to Genotoxic Stress

    Energy Technology Data Exchange (ETDEWEB)

    Kirshner, Julia; Jobling, Michael F.; Pajares, Maria Jose; Ravani, Shraddha A.; Glick, Adam B.; Lavin, Martin J.; Koslov, Sergei; Shiloh, Yosef; Barcellos-Hoff, Mary Helen

    2006-09-15

    Ionizing radiation causes DNA damage that elicits a cellular program of damage control coordinated by the kinase activity of ataxia telangiectasia mutated protein (ATM). Transforming growth factor {beta}1 (TGF{beta}), which is activated by radiation, is a potent and pleiotropic mediator of physiological and pathological processes. Here we show that TGF{beta} inhibition impedes the canonical cellular DNA damage stress response. Irradiated Tgf{beta}1 null murine epithelial cells or human epithelial cells treated with a small molecule inhibitor of TGF{beta} type I receptor kinase exhibit decreased phosphorylation of Chk2, Rad17 and p53, reduced {gamma}H2AX radiation-induced foci, and increased radiosensitivity compared to TGF{beta} competent cells. We determined that loss of TGF{beta} signaling in epithelial cells truncated ATM autophosphorylation and significantly reduced its kinase activity, without affecting protein abundance. Addition of TGF{beta} restored functional ATM and downstream DNA damage responses. These data reveal a heretofore undetected critical link between the microenvironment and ATM that directs epithelial cell stress responses, cell fate and tissue integrity. Thus, TGF{beta}1, in addition to its role in homoeostatic growth control, plays a complex role in regulating responses to genotoxic stress, the failure of which would contribute to the development of cancer; conversely, inhibiting TGF{beta} may be used to advantage in cancer therapy.

  20. Stress and glucocorticoids impair memory retrieval via β2-adrenergic, Gi/o-coupled suppression of cAMP signaling.

    Science.gov (United States)

    Schutsky, Keith; Ouyang, Ming; Castelino, Christina B; Zhang, Lei; Thomas, Steven A

    2011-10-05

    Acute stress impairs the retrieval of hippocampus-dependent memory, and this effect is mimicked by exogenous administration of stress-responsive glucocorticoid hormones. It has been proposed that glucocorticoids affect memory by promoting the release and/or blocking the reuptake of norepinephrine (NE), a stress-responsive neurotransmitter. It has also been proposed that this enhanced NE signaling impairs memory retrieval by stimulating β(1)-adrenergic receptors and elevating levels of cAMP. In contrast, other evidence indicates that NE, β(1), and cAMP signaling is transiently required for the retrieval of hippocampus-dependent memory. To resolve this discrepancy, wild-type rats and mice with and without gene-targeted mutations were stressed or treated with glucocorticoids and/or adrenergic receptor drugs before testing memory for inhibitory avoidance or fear conditioning. Here we report that glucocorticoids do not require NE to impair retrieval. However, stress- and glucocorticoid-induced impairments of retrieval depend on the activation of β(2) (but not β(1))-adrenergic receptors. Offering an explanation for the opposing functions of these two receptors, the impairing effects of stress, glucocorticoids and β(2) agonists on retrieval are blocked by pertussis toxin, which inactivates signaling by G(i/o)-coupled receptors. In hippocampal slices, β(2) signaling decreases cAMP levels and greatly reduces the increase in cAMP mediated by β(1) signaling. Finally, augmenting cAMP signaling in the hippocampus prevents the impairment of retrieval by systemic β(2) agonists or glucocorticoids. These results demonstrate that the β(2) receptor can be a critical effector of acute stress, and that β(1) and β(2) receptors can have quite distinct roles in CNS signaling and cognition.

  1. Anandamide-induced endoplasmic reticulum stress and apoptosis are mediated by oxidative stress in non-melanoma skin cancer: Receptor-independent endocannabinoid signaling.

    Science.gov (United States)

    Soliman, Eman; Van Dross, Rukiyah

    2016-11-01

    Endocannabinoids are neuromodulatory lipids that regulate central and peripheral physiological functions. Endocannabinoids have emerged as effective antitumor drugs due to their ability to induce apoptosis in various cancer studies. The G-protein coupled cannabinoid receptors (CB1 and CB2) and the TRPV1 ion channel were reported to mediate the antiproliferative activity of endocannabinoids. However, receptor-independent effects also account for their activity. Our previous studies showed that the antiproliferative activity of anandamide (AEA) was regulated by cyclooxygenase-2 (COX-2) via induction of endoplasmic reticulum (ER) stress. We also determined that AEA induced oxidative stress. However, the role of oxidative stress, the cannabinoid receptors, and TRPV1 in AEA-induced ER stress-apoptosis was unclear. Therefore, the current study examines the role of oxidative stress in ER stress-apoptosis and investigates whether this effect is modulated by CB1, CB2, or TRPV1. In non-melanoma skin cancer (NMSC) cells, AEA reduced the total intracellular level of glutathione and induced oxidative stress. To evaluate the importance of oxidative stress in AEA-induced cell death, the antioxidants, N-acetylcysteine (NAC) and Trolox, were utilized. Each antioxidant ameliorated the antiproliferative effect of AEA. Furthermore, Trolox inhibited AEA-induced CHOP10 expression and caspase 3 activity, indicating that oxidative stress was required for AEA-induced ER stress-apoptosis. On the other hand, selective blockade of CB1, CB2, and TRPV1 did not inhibit AEA-induced oxidative stress or ER stress-apoptosis. These findings suggest that AEA-induced ER stress-apoptosis in NMSC cells is mediated by oxidative stress through a receptor-independent mechanism. Hence, receptor-independent AEA signaling pathways may be targeted to eliminate NMSC. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  2. CDIP1-BAP31 Complex Transduces Apoptotic Signals from Endoplasmic Reticulum to Mitochondria under Endoplasmic Reticulum Stress

    OpenAIRE

    Takushi Namba; Fang Tian; Kiki Chu; So-Young Hwang; Kyoung Wan Yoon; Sanguine Byun; Masatsugu Hiraki; Anna Mandinova; Sam W. Lee

    2013-01-01

    Resolved endoplasmic reticulum (ER) stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a proapoptotic p53 target, CDIP1, acts as a key signal transducer of ER-stress-mediated apoptosis. We identify B-cell-receptor-associated protein 31 (BAP31) as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 i...

  3. Alcohol Dehydrogenase Protects against Endoplasmic Reticulum Stress-Induced Myocardial Contractile Dysfunction via Attenuation of Oxidative Stress and Autophagy: Role of PTEN-Akt-mTOR Signaling.

    Directory of Open Access Journals (Sweden)

    Jiaojiao Pang

    Full Text Available The endoplasmic reticulum (ER plays an essential role in ensuring proper folding of the newly synthesized proteins. Aberrant ER homeostasis triggers ER stress and development of cardiovascular diseases. ADH is involved in catalyzing ethanol to acetaldehyde although its role in cardiovascular diseases other than ethanol metabolism still remains elusive. This study was designed to examine the impact of ADH on ER stress-induced cardiac anomalies and underlying mechanisms involved using cardiac-specific overexpression of alcohol dehydrogenase (ADH.ADH and wild-type FVB mice were subjected to the ER stress inducer tunicamycin (1 mg/kg, i.p., for 48 hrs. Myocardial mechanical and intracellular Ca(2+ properties, ER stress, autophagy and associated cell signaling molecules were evaluated.ER stress compromised cardiac contractile function (evidenced as reduced fractional shortening, peak shortening, maximal velocity of shortening/relengthening, prolonged relengthening duration and impaired intracellular Ca(2+ homeostasis, oxidative stress and upregulated autophagy (increased LC3B, Atg5, Atg7 and p62, along with dephosphorylation of PTEN, Akt and mTOR, all of which were attenuated by ADH. In vitro study revealed that ER stress-induced cardiomyocyte anomaly was abrogated by ADH overexpression or autophagy inhibition using 3-MA. Interestingly, the beneficial effect of ADH was obliterated by autophagy induction, inhibition of Akt and mTOR. ER stress also promoted phosphorylation of the stress signaling ERK and JNK, the effect of which was unaffected by ADH transgene.Taken together, these findings suggested that ADH protects against ER stress-induced cardiac anomalies possibly via attenuation of oxidative stress and PTEN/Akt/mTOR pathway-regulated autophagy.

  4. Inflammatory stress increases hepatic CD36 translational efficiency via activation of the mTOR signalling pathway.

    Directory of Open Access Journals (Sweden)

    Chuan Wang

    Full Text Available Inflammatory stress is an independent risk factor for the development of non-alcoholic fatty liver disease (NAFLD. Although CD36 is known to facilitate long-chain fatty acid uptake and contributes to NAFLD progression, the mechanisms that link inflammatory stress to hepatic CD36 expression and steatosis remain unclear. As the mammalian target of rapamycin (mTOR signalling pathway is involved in CD36 translational activation, this study was undertaken to investigate whether inflammatory stress enhances hepatic CD36 expression via mTOR signalling pathway and the underlying mechanisms. To induce inflammatory stress, we used tumour necrosis factor alpha (TNF-α and interleukin-6 (IL-6 stimulation of the human hepatoblastoma HepG2 cells in vitro and casein injection in C57BL/6J mice in vivo. The data showed that inflammatory stress increased hepatic CD36 protein levels but had no effect on mRNA expression. A protein degradation assay revealed that CD36 protein stability was not different between HepG2 cells treated with or without TNF-α or IL-6. A polysomal analysis indicated that CD36 translational efficiency was significantly increased by inflammatory stress. Additionally, inflammatory stress enhanced the phosphorylation of mTOR and its downstream translational regulators including p70S6K, 4E-BP1 and eIF4E. Rapamycin, an mTOR-specific inhibitor, reduced the phosphorylation of mTOR signalling pathway and decreased the CD36 translational efficiency and protein level even under inflammatory stress resulting in the alleviation of inflammatory stress-induced hepatic lipid accumulation. This study demonstrates that the activation of the mTOR signalling pathway increases hepatic CD36 translational efficiency, resulting in increased CD36 protein expression under inflammatory stress.

  5. Periodic Mechanical Stress INDUCES Chondrocyte Proliferation and Matrix Synthesis via CaMKII-Mediated Pyk2 Signaling.

    Science.gov (United States)

    Liang, Wenwei; Li, Zeng; Wang, Zhen; Zhou, Jinchun; Song, Huanghe; Xu, Shun; Cui, Weiding; Wang, Qing; Chen, Zhefeng; Liu, Feng; Fan, Weimin

    2017-01-01

    Periodic mechanical stress can promote chondrocyte proliferation and matrix synthesis to improve the quality of tissue-engineered cartilage. Although the integrin β1-ERK1/2 signal cascade has been implicated in periodic mechanical stress-induced mitogenic effects in chondrocytes, the precise mechanisms have not been fully established. The current study was designed to probe the roles of CaMKII and Pyk2 signaling in periodic mechanical stress-mediated chondrocyte proliferation and matrix synthesis. Chondrocytes were subjected to periodic mechanical stress, proliferation was assessed by direct cell counting and CCK-8 assay; gene expressions were analyzed using quantitative real-time PCR, protein abundance by Western blotting. Mechanical stress, markedly enhanced the phosphorylation levels of Pyk2 at Tyr402 and CaMKII at Thr286. Both suppression of Pyk2 with Pyk2 inhibitor PF431396 or Pyk2 shRNA and suppression of CaMKII with CaMKII inhibitor KN-93 or CaMKII shRNA blocked periodic mechanical stress-induced chondrocyte proliferation and matrix synthesis. Additionally, either pretreatment with KN-93 or shRNA targeted to CaMKII prevented the activation of ERK1/2 and Pyk2 under conditions of periodic mechanical stress. Interestingly, in relation to periodic mechanical stress, in the context of Pyk2 inhibition with PF431396 or its targeted shRNA, only the phosphorylation levels of ERK1/2 were abrogated, while CaMKII signal activation was not affected. Moreover, the phosphorylation levels of CaMKII- Thr286 and Pyk2- Tyr402 were abolished after pretreatment with blocking antibody against integrinβ1 exposed to periodic mechanical stress. Our results collectively indicate that periodic mechanical stress promotes chondrocyte proliferation and matrix synthesis through the integrinβ1-CaMKII-Pyk2-ERK1/2 signaling cascade. © 2017 The Author(s). Published by S. Karger AG, Basel.

  6. Mammalian RAD52 Functions in Break-Induced Replication Repair of Collapsed DNA Replication Forks

    DEFF Research Database (Denmark)

    Sotiriou, Sotirios K; Kamileri, Irene; Lugli, Natalia

    2016-01-01

    Human cancers are characterized by the presence of oncogene-induced DNA replication stress (DRS), making them dependent on repair pathways such as break-induced replication (BIR) for damaged DNA replication forks. To better understand BIR, we performed a targeted siRNA screen for genes whose depl...

  7. Honest signaling and oxidative stress: the special case of avian acoustic communication

    Directory of Open Access Journals (Sweden)

    Stefania eCasagrande

    2016-05-01

    Full Text Available Much research on animal communication has addressed how costs or constraints determined by the oxidative status of an individual can assure the honesty of visual signals, such as sexually selected color ornaments. However, acoustic communication has been largely overlooked in this respect. Here, we describe the few available studies that have considered the role of oxidative status in mediating vocal behavior in adult and nestling birds. Further, we discuss the theoretical principles of how the honesty of avian acoustic signals may be maintained by an organism’s oxidative status. We here distinguish between studies that considered songs and begging calls as indicators of oxidative status and studies where vocalizations were assumed to be the source of oxidative costs. We outline experimental and methodological issues related to the study of bird vocalizations and oxidative stress and describe opportunities for future work in this field of research. Investigating the interactions between acoustic signals and redox state may help address some unresolved questions in avian vocalization, thereby increasing our understanding of the evolutionary pressures shaping animal communication. Finally, we argue that it will be important to extend this line of research beyond birds and include other taxa as well.

  8. Imipramine protects retinal ganglion cells from oxidative stress through the tyrosine kinase receptor B signaling pathway

    Institute of Scientific and Technical Information of China (English)

    Ming-lei Han; Guo-hua Liu; Jin Guo; Shu-juan Yu; Jing Huang

    2016-01-01

    Retinal ganglion cell (RGC) degeneration is irreversible in glaucoma and tyrosine kinase receptor B (TrkB)-associated signaling pathways have been implicated in the process. In this study, we attempted to examine whether imipramine, a tricyclic antidepressant, may protect hydrogen peroxide (H2O2)-induced RGC degeneration through the activation of the TrkB pathway in RGC-5 cell lines. RGC-5 cell lines were pre-treated with imipramine 30 minutes before exposure to H2O2. Western blot assay showed that in H2O2-damaged RGC-5 cells, imipramine activated TrkB pathways through extracellular signal-regulated protein kinase/TrkB phosphorylation. TUNEL staining assay also demonstrated that imipramine ameliorated H2O2-induced apoptosis in RGC-5 cells. Finally, TrkB-IgG intervention was able to reverse the protective effect of imipramine on H2O2-induced RGC-5 apoptosis. Imipramine therefore protects RGCs from oxidative stress-induced apoptosis through the TrkB signaling pathway.

  9. Arsenic stress induces changes in lipid signalling and evokes the stomata closure in soybean.

    Science.gov (United States)

    Armendariz, Ana L; Talano, Melina A; Villasuso, Ana L; Travaglia, Claudia; Racagni, Graciela E; Reinoso, Herminda; Agostini, Elizabeth

    2016-06-01

    Soybean (Glycine max) is often exposed to high arsenic (As) level in soils or through irrigation with groundwater. In previous studies on As-treated soybean seedlings we showed deleterious effect on growth, structural alterations mainly in root vascular system and induction of antioxidant enzymes. However, there are not reports concerning signal transduction pathways triggered by the metalloid in order to develop adaptive mechanisms. Phosphatidic acid (PA), a key messenger in plants, can be generated via phospholipase D (PLD) or via phospholipase C (PLC) coupled to diacylglycerol kinase (DGK). Thus, changes in PA and in an enzyme involved in its metabolism (PLD) were analysed in soybean seedlings treated with 25 μM AsV or AsIII. The present study demonstrated that As triggers the PA signal by PLD and also via PLC/DGK mainly after 48 h of As treatment. DGPP, other lipid messenger produced by phosphorylation of PA by PAK increased in As treated roots. Arsenic also induced rapid and significant stomatal closure after 1.5 h of treatment, mainly with AsIII, probably as an adaptive response to the metalloid to reduce water loss by transpiration. This report constitute the first evidence that shows the effects of As on lipid signalling events in soybean seedlings which would be crucial in adaptation and survival of soybean seedlings under As stress.

  10. Imipramine protects retinal ganglion cells from oxidative stress through the tyrosine kinase receptor B signaling pathway

    Directory of Open Access Journals (Sweden)

    Ming-lei Han

    2016-01-01

    Full Text Available Retinal ganglion cell (RGC degeneration is irreversible in glaucoma and tyrosine kinase receptor B (TrkB-associated signaling pathways have been implicated in the process. In this study, we attempted to examine whether imipramine, a tricyclic antidepressant, may protect hydrogen peroxide (H 2 O 2 -induced RGC degeneration through the activation of the TrkB pathway in RGC-5 cell lines. RGC-5 cell lines were pre-treated with imipramine 30 minutes before exposure to H 2 O 2 . Western blot assay showed that in H 2 O 2 -damaged RGC-5 cells, imipramine activated TrkB pathways through extracellular signal-regulated protein kinase/TrkB phosphorylation. TUNEL staining assay also demonstrated that imipramine ameliorated H 2 O 2 -induced apoptosis in RGC-5 cells. Finally, TrkB-IgG intervention was able to reverse the protective effect of imipramine on H 2 O 2 -induced RGC-5 apoptosis. Imipramine therefore protects RGCs from oxidative stress-induced apoptosis through the TrkB signaling pathway.

  11. The C-terminal domain of chikungunya virus nsP2 independently governs viral RNA replication, cytopathicity, and inhibition of interferon signaling

    NARCIS (Netherlands)

    Fros, J.J.; Maten, van der E.; Vlak, J.M.; Pijlman, G.P.

    2013-01-01

    Alphavirus nonstructural protein 2 (nsP2) has pivotal roles in viral RNA replication, host cell shutoff, and inhibition of antiviral responses. Mutations that individually rendered other alphaviruses noncytopathic were introduced into chikungunya virus nsP2. Results show that (i) nsP2 mutation P718S

  12. The C-terminal domain of chikungunya virus nsP2 independently governs viral RNA replication, cytopathicity, and inhibition of interferon signaling

    NARCIS (Netherlands)

    Fros, J.J.; Maten, van der E.; Vlak, J.M.; Pijlman, G.P.

    2013-01-01

    Alphavirus nonstructural protein 2 (nsP2) has pivotal roles in viral RNA replication, host cell shutoff, and inhibition of antiviral responses. Mutations that individually rendered other alphaviruses noncytopathic were introduced into chikungunya virus nsP2. Results show that (i) nsP2 mutation P718S

  13. Impaired cannabinoid receptor type 1 signaling interferes with stress-coping behavior in mice.

    Science.gov (United States)

    Steiner, M A; Wanisch, K; Monory, K; Marsicano, G; Borroni, E; Bächli, H; Holsboer, F; Lutz, B; Wotjak, C T

    2008-06-01

    Dysregulation of the endocannabinoid system is known to interfere with emotional processing of stressful events. Here, we studied the role of cannabinoid receptor type 1 (CB1) signaling in stress-coping behaviors using the forced swim test (FST) with repeated exposures. We compared effects of genetic inactivation with pharmacological blockade of CB1 receptors both in male and female mice. In addition, we investigated potential interactions of the endocannabinoid system with monoaminergic and neurotrophin systems of the brain. Naive CB1 receptor-deficient mice (CB1-/-) showed increased passive stress-coping behaviors as compared to wild-type littermates (CB1+/+) in the FST, independent of sex. These findings were partially reproduced in C57BL/6N animals and fully reproduced in female CB1+/+ mice by pharmacological blockade of CB1 receptors with the CB1 receptor antagonist SR141716. The specificity of SR141716 was confirmed in female CB1-/- mice, where it failed to affect behavioral performance. Sensitivity to the antidepressants desipramine and paroxetine was preserved, but slightly altered in female CB1-/- mice. There were no genotype differences between CB1+/+ and CB1-/- mice in monoamine oxidase A and B activities under basal conditions, nor in monoamine content of hippocampal tissue after FST exposure. mRNA expression of vesicular glutamate transporter type 1 was unaffected in CB1-/- mice, but mRNA expression of brain-derived neurotrophic factor (BDNF) was reduced in the hippocampus. Our results suggest that impaired CB1 receptor function promotes passive stress-coping behavior, which, at least in part, might relate to alterations in BDNF function.

  14. Traumatic Stress Promotes Hyperalgesia via Corticotropin-Releasing Factor-1 Receptor (CRFR1) Signaling in Central Amygdala.

    Science.gov (United States)

    Itoga, Christy A; Roltsch Hellard, Emily A; Whitaker, Annie M; Lu, Yi-Ling; Schreiber, Allyson L; Baynes, Brittni B; Baiamonte, Brandon A; Richardson, Heather N; Gilpin, Nicholas W

    2016-09-01

    Hyperalgesia is an exaggerated response to noxious stimuli produced by peripheral or central plasticity. Stress modifies nociception, and humans with post-traumatic stress disorder (PTSD) exhibit co-morbid chronic pain and amygdala dysregulation. Predator odor stress produces hyperalgesia in rodents. Systemic blockade of corticotropin-releasing factor (CRF) type 1 receptors (CRFR1s) reduces stress-induced thermal hyperalgesia. We hypothesized that CRF-CRFR1 signaling in central amygdala (CeA) mediates stress-induced hyperalgesia in rats with high stress reactivity. Adult male Wistar rats were exposed to predator odor stress in a conditioned place avoidance paradigm and indexed for high (Avoiders) and low (Non-Avoiders) avoidance of predator odor-paired context, or were unstressed Controls. Rats were tested for the latency to withdraw hindpaws from thermal stimuli (Hargreaves test). We used pharmacological, molecular, and immunohistochemical techniques to assess the role of CRF-CRFR1 signaling in CeA in stress-induced hyperalgesia. Avoiders exhibited higher CRF peptide levels in CeA that did not appear to be locally synthesized. Intra-CeA CRF infusion mimicked stress-induced hyperalgesia. Avoiders exhibited thermal hyperalgesia that was reversed by systemic or intra-CeA injection of a CRFR1 antagonist. Finally, intra-CeA infusion of tetrodotoxin produced thermal hyperalgesia in unstressed rats and blocked the anti-hyperalgesic effect of systemic CRFR1 antagonist in stressed rats. These data suggest that rats with high stress reactivity exhibit hyperalgesia that is mediated by CRF-CRFR1 signaling in CeA.

  15. Restoration of autophagy alleviates hepatic ER stress and impaired insulin signalling transduction in high fructose-fed male mice.

    Science.gov (United States)

    Wang, Hao; Sun, Ruo-Qiong; Zeng, Xiao-Yi; Zhou, Xiu; Li, Songpei; Jo, Eunjung; Molero, Juan C; Ye, Ji-Ming

    2015-01-01

    High-carbohydrate (mainly fructose) consumption is a major dietary factor for hepatic insulin resistance, involving endoplasmic reticulum (ER) stress and lipid accumulation. Because autophagy has been implicated in ER stress, the present study investigated the role of autophagy in high-fructose (HFru) diet-induced hepatic ER stress and insulin resistance in male C57BL/6J mice. The results show that chronic HFru feeding induced glucose intolerance and impaired insulin signaling transduction in the liver, associated with ER stress and the accumulation of lipids. Intriguingly, hepatic autophagy was suppressed as a result of activation of mammalian target of rapamycin. The suppressed autophagy was detected within 6 hours after HFru feeding along with activation of both inositol-requiring enzyme 1 and protein kinase RNA-like endoplasmic reticulum kinase pathways. These events occurred prior to lipid accumulation or lipogenesis and were sufficient to blunt insulin signaling transduction with activation of c-Jun N-terminal kinase/inhibitory-κB kinase and serine phosphorylation of insulin receptor substrate 1. The stimulation of autophagy attenuated ER stress- and c-Jun N-terminal kinase/inhibitory-κB kinase-associated impairment in insulin signaling transduction in a mammalian target of rapamycin -independent manner. Taken together, our data suggest that restoration of autophagy functions disrupted by fructose is able to alleviate ER stress and improve insulin signaling transduction.

  16. Anger Emotional Stress Influences VEGF/VEGFR2 and Its Induced PI3K/AKT/mTOR Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Peng Sun

    2016-01-01

    Full Text Available Objective. We discuss the influence of anger emotional stress upon VEGF/VEGFR2 and its induced PI3K/AKT/mTOR signal pathway. Methods. We created a rat model of induced anger (anger-out and anger-in emotional response using social isolation and resident-intruder paradigms and assessed changes in hippocampus’ VEGF content, neuroplasticity, and the PI3K/AKT/mTOR signaling pathway. Results. The resident-intruder method successfully generated anger-out and anger-in models that differed significantly in composite aggression score, aggression incubation, open field behavior, sucrose preference, and weight gain. Anger emotional stress decreased synaptic connections and VEGFR2 expression. Anger emotional stress led to abnormal expression of VEGF/VEGFR2 mRNA and protein and disorderly expression of key factors in the PI3K/AKT/mTOR signal pathway. Fluoxetine administration ameliorated behavioral abnormalities and damage to hippocampal neurons caused by anger emotional stress, as well as abnormal expression of some proteins in VEGF/VEGFR2 and its induced PI3K/AKT/mTOR signal pathway. Conclusion. This research provides a detailed classification of anger emotion and verifies its influence upon VEGF and the VEGF-induced signaling pathway, thus providing circumstantial evidence of mechanisms by which anger emotion damages neurogenesis. As VEGFR2 can promote neurogenesis and vasculogenesis in the hippocampus and frontal lobe, these results suggest that anger emotional stress can result in decreased neurogenesis.

  17. Alternative Oxidase: A Mitochondrial Respiratory Pathway to Maintain Metabolic and Signaling Homeostasis during Abiotic and Biotic Stress in Plants

    Directory of Open Access Journals (Sweden)

    Greg C. Vanlerberghe

    2013-03-01

    Full Text Available Alternative oxidase (AOX is a non-energy conserving terminal oxidase in the plant mitochondrial electron transport chain. While respiratory carbon oxidation pathways, electron transport, and ATP turnover are tightly coupled processes, AOX provides a means to relax this coupling, thus providing a degree of metabolic homeostasis to carbon and energy metabolism. Beside their role in primary metabolism, plant mitochondria also act as “signaling organelles”, able to influence processes such as nuclear gene expression. AOX activity can control the level of potential mitochondrial signaling molecules such as superoxide, nitric oxide and important redox couples. In this way, AOX also provides a degree of signaling homeostasis to the organelle. Evidence suggests that AOX function in metabolic and signaling homeostasis is particularly important during stress. These include abiotic stresses such as low temperature, drought, and nutrient deficiency, as well as biotic stresses such as bacterial infection. This review provides an introduction to the genetic and biochemical control of AOX respiration, as well as providing generalized examples of how AOX activity can provide metabolic and signaling homeostasis. This review also examines abiotic and biotic stresses in which AOX respiration has been critically evaluated, and considers the overall role of AOX in growth and stress tolerance.

  18. A modified hTERT promoter-directed oncolytic adenovirus replication with concurrent inhibition of TGFbeta signaling for breast cancer therapy.

    Science.gov (United States)

    Hu, Z; Robbins, J S; Pister, A; Zafar, M B; Zhang, Z-W; Gupta, J; Lee, K J; Newman, K; Neuman, K; Yun, C-O; Guise, T; Seth, P

    2010-04-01

    We were interested in developing oncolytic adenoviral vectors that can be administered systemically for the treatment of breast cancer. To restrict viral replication in breast tumor cells, we constructed mhTERTAd.sTbetaRFc, a 01/07-based adenoviral vector expressing the soluble form of transforming growth factor-beta (TGFbeta) receptor II fused with the human Fc IgG1 (sTGFbetaRIIFc) gene, in which viral replication is under the control of a modified human telomerase reverse transcriptase (mhTERT) promoter. In addition, mhTERTAd.sTbetaRFc-mediated sTGFbetaRIIFc production targets the TGFbeta pathway known to contribute to the tumor progression of breast cancer metastasis. We chose to use the mhTERT promoter because it was found to be relatively more active (approximately 20 times) in breast cancer cells compared with normal human cells. We showed that infection of MDA-MB-231 and MCF-7 breast cancer cells for 48 h with mhTERTAd.sTbetaRFc produced high levels of sTGFbetaRIIFc (greater than 1 microg ml(-1)) in the medium. Breast cancer cells produced nearly a 6000-fold increase in viral titers during the 48 h infection period. However, mhTERTAd.sTbetaRFc replication was attenuated in normal cells. Infection of breast cancer cells with a replication-deficient virus Ad(E1(-)).sTbetaRFc also produced high levels of sTGFbetaRIIFc, but under these conditions, no detectable viral replication was observed. Adenoviral-mediated production of sTGFbetaRIIFc was shown to bind with TGFbeta-1, and to abolish the effects of TGFbeta-1 on downstream SMAD-3 phosphorylation. The administration of mhTERTAd.sTbetaRFc intravenously into MDA-MB-231 human xenograft-bearing mice resulted in a significant inhibition of tumor growth and production of sTGFbetaRIIFc in the blood. Conversely, intravenous injection of Ad(E1(-)).sTbetaRFc did not show a significant inhibition of tumor growth, but resulted in sTGFbetaRIIFc in the blood, suggesting that viral replication along with s

  19. A modified hTERT Promoter-directed Oncolytic Adenovirus Replication with Concurrent Inhibition of TGFβ Signaling for Breast Cancer Therapy

    Science.gov (United States)

    Hu, Zebin; Robbins, John S.; Pister, Amanda; Zafar, M. Behzad; Zhang, Zhen-Wei; Gupta, Janhavi; Lee, K. Jessica; Neuman, Kam; Yun, Chae-Ok; Guise, Theresa; Seth, Prem

    2009-01-01

    Our laboratory is interested to develop oncolytic adenoviral vectors that can be administered systemically for the treatment of breast cancer. To restrict viral replication in breast tumor cells, we have constructed mhTERTAd.sTβRFc, a 01/07 based adenoviral vector expressing the soluble form of TGFβ receptor II fused with human Fc IgG1 (sTGFβRIIFc) gene, in which viral replication is under the control of modified human telomerase reverse transcriptase (mhTERT) promoter. In addition, mhTERTAd.sTβRFc-mediated sTGFβRIIFc production would target growth factor-β (TGFβ) pathway known to contribute to the tumor progression breast cancer metastasis. We chose to use mhTERT promoter because it was found to be relatively more active (approximately 20-times) in breast cancer cells compared to normal human cells. We showed that infection of MDA-MB-231 and MCF-7 breast cancer cells for 48 hrs with mhTERTAd.sTβRFc produced high levels of sTGFβRIIFc (greater than 1 μg/ml) in the medium. Breast cancer cells produced nearly 6,000-fold increase in the viral titers during 48 hrs infection period. However, mhTERTAd.sTβRFc replication was attenuated in normal cells. Infection of breast cancer cells with a replication deficient virus Ad(E1-).sTβRFc also produced high levels of sTGFβRIIFc, but under these conditions no detectable viral replication was observed. Adenoviral-mediated production of sTGFβRIIFc was shown to bind with TGFβ-1, and abolished the effects of TGFβ-1 on downstream SMAD-3 phosphorylation. The administration of mhTERTAd.sTβRFc intravenously into MDA-MB-231 human xenograft bearing mice resulted in significant inhibition of tumor growth, and production of sTGFβRIIFc in the blood. On the other hand, intravenous injection of Ad(E1-).sTβRFc did not exhibit significant inhibition of the tumor growth, but resulted in the sTGFβRIIFc in the blood, suggesting that viral replication along with sTGFβRIIFc protein production play a critical role in inducing

  20. G-protein signalling components GCR1 and GPA1 mediate responses to multiple abiotic stresses in Arabidopsis

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    Navjyoti eChakraborty

    2015-11-01

    Full Text Available G-protein signalling components have been implicated in some individual stress responses in Arabidopsis, but have not been comprehensively evaluated at the genetic and biochemical level. Stress emerged as the largest functional category in our whole transcriptome analyses of knock-out mutants of GCR1 and/or GPA1 in Arabidopsis (Chakraborty et al., 2015a, PloS one 10, e0117819 and Chakraborty et al., 2015b, Plant Mol. Biol., doi: 10.1007/s11103-015-0374-2. This led us to ask whether G-protein signalling components offer converging points in the plant’s response to multiple abiotic stresses. In order to test this hypothesis, we carried out detailed analysis of the stress category in the present study, which revealed 144 differentially expressed genes (DEGs, spanning a wide range of abiotic stresses, including heat, cold, salt, light stress etc. Only 10 of these DEGs are shared by all the three mutants, while the single mutants (GCR1/GPA1 shared more DEGs between themselves than with the double mutant (GCR1-GPA1. RT-qPCR validation of 28 of these genes spanning different stresses revealed identical regulation of the DEGs shared between the mutants. We also validated the effects of cold, heat and salt stresses in all the 3 mutants and WT on % germination, root and shoot length, relative water content, proline content, lipid peroxidation and activities of catalase, ascorbate peroxidase and superoxide dismutase. All the 3 mutants showed evidence of stress tolerance, especially to cold, followed by heat and salt, in terms of all the above parameters. This clearly shows the role of GCR1 and GPA1 in mediating the plant’s response to multiple abiotic stresses for the first time, especially cold, heat and salt stresses. This also implies a role for classical G-protein signalling pathways in stress sensitivity in the normal plants of Arabidopsis. This is also the first genetic and biochemical evidence of abiotic stress tolerance rendered by knock

  1. Stress response, gut microbial diversity and sexual signals correlate with social interactions.

    Science.gov (United States)

    Levin, Iris I; Zonana, David M; Fosdick, Bailey K; Song, Se Jin; Knight, Rob; Safran, Rebecca J

    2016-06-01

    Theory predicts that social interactions are dynamically linked to phenotype. Yet because social interactions are difficult to quantify, little is known about the precise details on how interactivity is linked to phenotype. Here, we deployed proximity loggers on North American barn swallows (Hirundo rustica erythrogaster) to examine intercorrelations among social interactions, morphology and features of the phenotype that are sensitive to the social context: stress-induced corticosterone (CORT) and gut microbial diversity. We analysed relationships at two spatial scales of interaction: (i) body contact and (ii) social interactions occurring between 0.1 and 5 m. Network analysis revealed that relationships between social interactions, morphology, CORT and gut microbial diversity varied depending on the sexes of the individuals interacting and the spatial scale of interaction proximity. We found evidence that body contact interactions were related to diversity of socially transmitted microbes and that looser social interactions were related to signalling traits and CORT.

  2. Mst1-FoxO signaling protects Naive T lymphocytes from cellular oxidative stress in mice.

    Directory of Open Access Journals (Sweden)

    Juhyun Choi

    Full Text Available BACKGROUND: The Ste-20 family kinase Hippo restricts cell proliferation and promotes apoptosis for proper organ development in Drosophila. In C. elegans, Hippo homolog also regulates longevity. The mammalian Ste20-like protein kinase, Mst1, plays a role in apoptosis induced by various types of apoptotic stress. Mst1 also regulates peripheral naïve T cell trafficking and proliferation in mice. However, its functions in mammals are not fully understood. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that the Mst1-FoxO signaling pathway plays a crucial role in survival, but not apoptosis, of naïve T cells. In Mst1(-/- mice, peripheral T cells showed impaired FoxO1/3 activation and decreased FoxO protein levels. Consistently, the FoxO targets, Sod2 and catalase, were significantly down-regulated in Mst1(-/- T cells, thereby resulting in elevated levels of intracellular reactive oxygen species (ROS and induction of apoptosis. Expression of constitutively active FoxO3a restored Mst1(-/- T cell survival. Crossing Mst1 transgenic mice (Mst1 Tg with Mst1(-/- mice reduced ROS levels and restored normal numbers of peripheral naïve T cells in Mst1 Tg;Mst1(-/- progeny. Interestingly, peripheral T cells from Mst1(-/- mice were hypersensitive to gamma-irradiation and paraquat-induced oxidative stresses, whereas those from Mst1 Tg mice were resistant. CONCLUSIONS/SIGNIFICANCE: These data support the hypothesis that tolerance to increased levels of intracellular ROS provided by the Mst1-FoxOs signaling pathway is crucial for the maintenance of naïve T cell homeostasis in the periphery.

  3. Vitamin D Potentiates the Inhibitory Effect of MicroRNA-130a in Hepatitis C Virus Replication Independent of Type I Interferon Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Xiaoqiong Duan

    2015-01-01

    Full Text Available Calcitriol, the bioactive metabolite of vitamin D, was reported to inhibit HCV production in a synergistic fashion with interferon, a treatment in vitro. Our previous study established that miR-130a inhibits HCV replication by restoring the host innate immune response. We aimed to determine whether there is additive inhibitory effect of calcitriol and miR-130a on HCV replication. Here we showed that calcitriol potentiates the anti-HCV effect of miR-130a in both Con1b replicon and J6/JFH1 culture systems. Intriguingly, this potentiating effect of calcitriol on miR-130a was not through upregulating the expression of cellular miR-130a or through increasing the miR-130a-mediated IFNα/β production. All these findings may contribute to the development of novel anti-HCV therapeutic strategies although the antiviral mechanism needs to be further investigated.

  4. Group VII Ethylene Response Factors Coordinate Oxygen and Nitric Oxide Signal Transduction and Stress Responses in Plants1

    Science.gov (United States)

    Gibbs, Daniel J.; Conde, Jorge Vicente; Berckhan, Sophie; Prasad, Geeta; Mendiondo, Guillermina M.; Holdsworth, Michael J.

    2015-01-01

    The group VII ethylene response factors (ERFVIIs) are plant-specific transcription factors that have emerged as important regulators of abiotic and biotic stress responses, in particular, low-oxygen stress. A defining feature of ERFVIIs is their conserved N-terminal domain, which renders them oxygen- and nitric oxide (NO)-dependent substrates of the N-end rule pathway of targeted proteolysis. In the presence of these gases, ERFVIIs are destabilized, whereas an absence of either permits their accumulation; ERFVIIs therefore coordinate plant homeostatic responses to oxygen availability and control a wide range of NO-mediated processes. ERFVIIs have a variety of context-specific protein and gene interaction partners, and also modulate gibberellin and abscisic acid signaling to regulate diverse developmental processes and stress responses. This update discusses recent advances in our understanding of ERFVII regulation and function, highlighting their role as central regulators of gaseous signal transduction at the interface of ethylene, oxygen, and NO signaling. PMID:25944828

  5. Context Specificity of Stress-activated Mitogen-activated Protein (MAP) Kinase Signaling: The Story as Told by Caenorhabditis elegans.

    Science.gov (United States)

    Andrusiak, Matthew G; Jin, Yishi

    2016-04-01

    Stress-associated p38 and JNK mitogen-activated protein (MAP) kinase signaling cascades trigger specific cellular responses and are involved in multiple disease states. At the root of MAP kinase signaling complexity is the differential use of common components on a context-specific basis. The roundwormCaenorhabditis eleganswas developed as a system to study genes required for development and nervous system function. The powerful genetics ofC. elegansin combination with molecular and cellular dissections has led to a greater understanding of how p38 and JNK signaling affects many biological processes under normal and stress conditions. This review focuses on the studies revealing context specificity of different stress-activated MAPK components inC. elegans.

  6. Fluorescent reporter signals, EGFP and DsRed, encoded in HIV-1 facilitate the detection of productively infected cells and cell-associated viral replication levels

    Directory of Open Access Journals (Sweden)

    Kazutaka eTerahara

    2012-01-01

    Full Text Available Flow cytometric analysis is a reliable and convenient method for investigating molecules at the single cell level. Previously, recombinant human immunodeficiency virus type 1 (HIV-1 strains were constructed that express a fluorescent reporter, either enhanced green fluorescent protein or DsRed, which allow the monitoring of HIV-1-infected cells by flow cytometry. The present study further investigated the potential of these recombinant viruses in terms of whether the HIV-1 fluorescent reporters would be helpful in evaluating viral replication based on fluorescence intensity. When primary CD4+ T cells were infected with recombinant viruses, the fluorescent reporter intensity measured by flow cytometry was associated with the level of CD4 downmodulation and Gag p24 expression in infected cells. Interestingly, some HIV-1-infected cells, in which CD4 was only moderately downmodulated, were reporter-positive but Gag p24-negative. Furthermore, when the activation status of primary CD4+ T cells was modulated by T cell receptor-mediated stimulation, we confirmed the preferential viral production upon strong stimulation and showed that the intensity of the fluorescent reporter within a proportion of HIV-1-infected cells was correlated with the viral replication level. These findings indicate that a fluorescent reporter encoded within HIV-1 is useful for the sensitive detection of productively-infected cells at different stages of infection and for evaluating cell-associated viral replication at the single cell level.

  7. Cytosolic acidification as a signal mediating hyperosmotic stress responses in Dictyostelium discoideum

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    Klein Gérard

    2001-06-01

    Full Text Available Abstract Background Dictyostelium cells exhibit an unusual response to hyperosmolarity that is distinct from the response in other organisms investigated: instead of accumulating compatible osmolytes as it has been described for a wide range of organisms, Dictyostelium cells rearrange their cytoskeleton and thereby build up a rigid network which is believed to constitute the major osmoprotective mechanism in this organism. To gain more insight into the osmoregulation of this amoeba, we investigated physiological processes affected under hyperosmotic conditions in Dictyostelium. Results We determined pH changes in response to hyperosmotic stress using FACS or 31P-NMR. Hyperosmolarity was found to acidify the cytosol from pH 7.5 to 6.8 within 5 minutes, whereas the pH of the endo-lysosomal compartment remained constant. Fluid-phase endocytosis was identified as a possible target of cytosolic acidification, as the inhibition of endocytosis observed under hypertonic conditions can be fully attributed to cytosolic acidification. In addition, a deceleration of vesicle mobility and a decrease in the NTP pool was observed. Conclusion Together, these results indicate that hyperosmotic stress triggers pleiotropic effects, which are partially mediated by a pH signal and which all contribute to the downregulation of cellular activity. The comparison of our results with the effect of hyperosmolarity and intracellular acidification on receptor-mediated endocytosis in mammalian cells reveals striking similarities, suggesting the hypothesis of the same mechanism of inhibition by low internal pH.

  8. Targeting PKC: a novel role for beta-catenin in ER stress and apoptotic signaling.

    Science.gov (United States)

    Raab, Marc S; Breitkreutz, Iris; Tonon, Giovanni; Zhang, Jing; Hayden, Patrick J; Nguyen, Thu; Fruehauf, Johannes H; Lin, Boris K; Chauhan, Dharminder; Hideshima, Teru; Munshi, Nikhil C; Anderson, Kenneth C; Podar, Klaus

    2009-02-12

    Targeting protein kinase C (PKC) isoforms by the small molecule inhibitor enzastaurin has shown promising preclinical activity in a wide range of tumor cells. We further delineated its mechanism of action in multiple myeloma (MM) cells and found a novel role of beta-catenin in regulating growth and survival of tumor cells. Specifically, inhibition of PKC leads to rapid accumulation of beta-catenin by preventing the phosphorylation required for its proteasomal degradation. Microarray analysis and small-interfering RNA (siRNA)-mediated gene silencing in MM cells revealed that accumulated beta-catenin activates early endoplasmic reticulum stress signaling via eIF2alpha, C/EBP-homologous protein (CHOP), and p21, leading to immediate growth inhibition. Furthermore, accumulated beta-catenin contributes to enzastaurin-induced cell death. Sequential knockdown of beta-catenin, c-Jun, and p73, as well as overexpression of beta-catenin or p73 confirmed that accumulated beta-catenin triggers c-Jun-dependent induction of p73, thereby conferring MM cell apoptosis. Our data reveal a novel role of beta-catenin in endoplasmic reticulum (ER) stress-mediated growth inhibition and a new proapoptotic mechanism triggered by beta-catenin on inhibition of PKC isoforms. Moreover, we identify p73 as a potential novel therapeutic target in MM. Based on these and previous data, enzastaurin is currently under clinical investigation in a variety of hematologic malignancies, including MM.

  9. A New Approach to Oxidative Stress and Inflammatory Signaling during Labour in Healthy Mothers and Neonates

    Directory of Open Access Journals (Sweden)

    Javier Díaz-Castro

    2015-01-01

    Full Text Available The objective of the current study was to investigate for the first time and simultaneously the oxidative stress and inflammatory signaling induced during the delivery in healthy mothers and their neonates. 56 mothers with normal gestational course and spontaneous delivery were selected. Blood samples were taken from mother (before and after delivery both from vein and artery of umbilical cord. Lower antioxidant enzymes activities were observed in neonates compared with their mothers and lower oxidative stress in umbilical cord artery with respect to vein. There was an overexpression of inflammatory cytokines in the mother, such as IL-6 and TNF-α, and, in addition, PGE2 was also increased. Neonates showed lower levels of IL-6 and TNF-α and higher values of sTNF-RII and PGE2 in comparison with their mothers. Parturition increases oxidative damage in the mother, although the indicators of oxidative damage were lower in umbilical cord artery with respect to umbilical vein. The overexpression of inflammatory cytokines reveals that fetus suffers its own inflammatory process during parturition.

  10. A new approach to oxidative stress and inflammatory signaling during labour in healthy mothers and neonates.

    Science.gov (United States)

    Díaz-Castro, Javier; Florido, Jesus; Kajarabille, Naroa; Prados, Sonia; de Paco, Catalina; Ocon, Olga; Pulido-Moran, Mario; Ochoa, Julio J

    2015-01-01

    The objective of the current study was to investigate for the first time and simultaneously the oxidative stress and inflammatory signaling induced during the delivery in healthy mothers and their neonates. 56 mothers with normal gestational course and spontaneous delivery were selected. Blood samples were taken from mother (before and after delivery) both from vein and artery of umbilical cord. Lower antioxidant enzymes activities were observed in neonates compared with their mothers and lower oxidative stress in umbilical cord artery with respect to vein. There was an overexpression of inflammatory cytokines in the mother, such as IL-6 and TNF-α, and, in addition, PGE2 was also increased. Neonates showed lower levels of IL-6 and TNF-α and higher values of sTNF-RII and PGE2 in comparison with their mothers. Parturition increases oxidative damage in the mother, although the indicators of oxidative damage were lower in umbilical cord artery with respect to umbilical vein. The overexpression of inflammatory cytokines reveals that fetus suffers its own inflammatory process during parturition.

  11. Plasticity of the MAPK signaling network in response to mechanical stress.

    Directory of Open Access Journals (Sweden)

    Andrea M Pereira

    Full Text Available Cells display versatile responses to mechanical inputs and recent studies have identified the mitogen-activated protein kinase (MAPK cascades mediating the biological effects observed upon mechanical stimulation. Although, MAPK pathways can act insulated from each other, several mechanisms facilitate the crosstalk between the components of these cascades. Yet, the combinatorial complexity of potential molecular interactions between these elements have prevented the understanding of their concerted functions. To analyze the plasticity of the MAPK signaling network in response to mechanical stress we performed a non-saturating epistatic screen in resting and stretched conditions employing as readout a JNK responsive dJun-FRET biosensor. By knocking down MAPKs, and JNK pathway regulators, singly or in pairs in Drosophila S2R+ cells, we have uncovered unexpected regulatory links between JNK cascade kinases, Rho GTPases, MAPKs and the JNK phosphatase Puc. These relationships have been integrated in a system network model at equilibrium accounting for all experimentally validated interactions. This model allows predicting the global reaction of the network to its modulation in response to mechanical stress. It also highlights its context-dependent sensitivity.

  12. Low zinc environment induces stress signaling, senescence and mixed cell death modalities in colon cancer cells.

    Science.gov (United States)

    Rudolf, Emil; Rudolf, Kamil

    2015-12-01

    Currently it is not clear what type of the final cellular response (i.e. cell death modality or senescence) is induced upon chronic intracellular zinc depletion in colon cancer cells. To address this question, isogenic colon cancer lines SW480 and SW620 exposed to low zinc environment were studied over the period of 6 weeks. Low zinc environment reduced total as well as free intracellular zinc content in both cell lines. Decreased intracellular zinc content resulted in changes in cellular proliferation, cell cycle distribution and activation of stress signaling. In addition, colonocytes with low zinc content displayed increased levels of oxidative stress, changes in mitochondrial activity but in the absence of significant DNA damage. Towards the end of treatment (4th-6th week), exposed cells started to change morphologically, and typical markers of senescence as well as cell death appeared. Of two examined colon cancer cell lines, SW480 cells proved to activate predominantly senescent phenotype, with frequent form of demise being necrosis and mixed cell death modality but not apoptosis. Conversely, SW620 cells activated mostly cell death, with relatively equal distribution of apoptosis and mixed types, while senescent phenotypes and necrosis were present only in a small fraction of cell populations. Addition of zinc at the beginning of 4th week of treatment significantly suppressed cell death phenotypes in both cell lines but had no significant effect on senescence. In conclusion, presented results demonstrate variability of responses to chronic zinc depletion in colon cancer as modeled in vitro.

  13. From stress to inflammation and major depressive disorder: a social signal transduction theory of depression.

    Science.gov (United States)

    Slavich, George M; Irwin, Michael R

    2014-05-01

    Major life stressors, especially those involving interpersonal stress and social rejection, are among the strongest proximal risk factors for depression. In this review, we propose a biologically plausible, multilevel theory that describes neural, physiologic, molecular, and genomic mechanisms that link experiences of social-environmental stress with internal biological processes that drive depression pathogenesis. Central to this social signal transduction theory of depression is the hypothesis that experiences of social threat and adversity up-regulate components of the immune system involved in inflammation. The key mediators of this response, called proinflammatory cytokines, can in turn elicit profound changes in behavior, which include the initiation of depressive symptoms such as sad mood, anhedonia, fatigue, psychomotor retardation, and social-behavioral withdrawal. This highly conserved biological response to adversity is critical for survival during times of actual physical threat or injury. However, this response can also be activated by modern-day social, symbolic, or imagined threats, leading to an increasingly proinflammatory phenotype that may be a key phenomenon driving depression pathogenesis and recurrence, as well as the overlap of depression with several somatic conditions including asthma, rheumatoid arthritis, chronic pain, metabolic syndrome, cardiovascular disease, obesity, and neurodegeneration. Insights from this theory may thus shed light on several important questions including how depression develops, why it frequently recurs, why it is strongly predicted by early life stress, and why it often co-occurs with symptoms of anxiety and with certain physical disease conditions. This work may also suggest new opportunities for preventing and treating depression by targeting inflammation.

  14. dsRNA-Dependent Protein Kinase PKR and its Role in Stress, Signaling and HCV Infection

    Directory of Open Access Journals (Sweden)

    Eliane F. Meurs

    2012-10-01

    Full Text Available The double-stranded RNA-dependent protein kinase PKR plays multiple roles in cells, in response to different stress situations. As a member of the interferon (IFN‑Stimulated Genes, PKR was initially recognized as an actor in the antiviral action of IFN, due to its ability to control translation, through phosphorylation, of the alpha subunit of eukaryotic initiation factor 2 (eIF2a. As such, PKR participates in the generation of stress granules, or autophagy and a number of viruses have designed strategies to inhibit its action. However, PKR deficient mice resist most viral infections, indicating that PKR may play other roles in the cell other than just acting as an antiviral agent. Indeed, PKR regulates several signaling pathways, either as an adapter protein and/or using its kinase activity. Here we review the role of PKR as an eIF2a kinase, its participation in the regulation of the NF-kB, p38MAPK and insulin pathways, and we focus on its role during infection with the hepatitis C virus (HCV. PKR binds the HCV IRES RNA, cooperates with some functions of the HCV core protein and may represent a target for NS5A or E2. Novel data points out for a role of PKR as a pro-HCV agent, both as an adapter protein and as an eIF2a-kinase, and in cooperation with the di-ubiquitin-like protein ISG15. Developing pharmaceutical inhibitors of PKR may help in resolving some viral infections as well as stress-related damages.

  15. Iron is a signal for Stenotrophomonas maltophilia biofilm formation, oxidative stress response, OMPs expression and virulence

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    Carlos Adrian Garcia

    2015-09-01

    Full Text Available Stenotrophomonas maltophilia is an emerging nosocomial pathogen. In many bacteria iron availability regulates, trough the Fur system, not only iron homeostasis but also virulence. The aim of this work was to assess the role of iron on S. maltophilia biofilm formation, EPS production, oxidative stress response, OMPs regulation, quorum sensing (QS, and virulence. Studies were done on K279 and its isogenic fur mutant F60 cultured in the presence or absence of dipyridyl. This is the first report of spontaneous fur mutants obtained in S. maltophilia. F60 produced higher amounts of biofilms than K279a and CLSM analysis demonstrated improved adherence and biofilm organization. Under iron restricted conditions, K279a produced biofilms with more biomass and enhanced thickness. In addition, F60 produced higher amounts of EPS than K279a but with a similar composition, as revealed by ATR-FTIR spectroscopy. With respect to the oxidative stress response, MnSOD was the only SOD isoenzyme detected in K279a. F60 presented higher SOD activity than the wt strain in planktonic and biofilm cultures, and iron deprivation increased K279a SOD activity. Under iron starvation, SDS-PAGE profile from K279a presented two iron-repressed proteins. Mass spectrometry analysis revealed homology with FepA and another putative TonB-dependent siderophore receptor of K279a. In silico analysis allowed the detection of potential Fur boxes in the respective coding genes. K279a encodes the QS diffusible signal factor (DSF. Under iron restriction K279a produced higher amounts of DSF than under iron rich condition. Finally, F60 was more virulent than K279a in the Galleria mellonella killing assay. These results put in evidence that iron levels regulate, likely through the Fur system, S. maltophilia biofilm formation, oxidative stress response, OMPs expression, DSF production and virulence.

  16. From Stress to Inflammation and Major Depressive Disorder: A Social Signal Transduction Theory of Depression

    Science.gov (United States)

    Slavich, George M.; Irwin, Michael R.

    2014-01-01

    Major life stressors, especially those involving interpersonal stress and social rejection, are among the strongest proximal risk factors for depression. In this review, we propose a biologically plausible, multilevel theory that describes neural, physiologic, molecular, and genomic mechanisms that link experiences of social-environmental stress with internal biological processes that drive depression pathogenesis. Central to this social signal transduction theory of depression is the hypothesis that experiences of social threat and adversity up-regulate components of the immune system involved in inflammation. The key mediators of this response, called proinflammatory cytokines, can in turn elicit profound changes in behavior, which include the initiation of depressive symptoms such as sad mood, anhedonia, fatigue, psychomotor retardation, and social-behavioral withdrawal. This highly conserved biological response to adversity is critical for survival during times of actual physical threat or injury. However, this response can also be activated by modern-day social, symbolic, or imagined threats, leading to an increasingly proinflammatory phenotype that may be a key phenomenon driving depression pathogenesis and recurrence, as well as the overlap of depression with several somatic conditions including asthma, rheumatoid arthritis, chronic pain, metabolic syndrome, cardiovascular disease, obesity, and neurodegeneration. Insights from this theory may thus shed light on several important questions including how depression develops, why it frequently recurs, why it is strongly predicted by early life stress, and why it often co-occurs with symptoms of anxiety and with certain physical disease conditions. This work may also suggest new opportunities for preventing and treating depression by targeting inflammation. PMID:24417575

  17. DVC1 (C1orf124) is a DNA damage-targeting p97 adaptor that promotes ubiquitin-dependent responses to replication blocks

    DEFF Research Database (Denmark)

    Mosbech, Anna; Gibbs-Seymour, Ian; Kagias, Konstantinos;

    2012-01-01

    Ubiquitin-mediated processes orchestrate critical DNA-damage signaling and repair pathways. We identify human DVC1 (C1orf124; Spartan) as a cell cycle-regulated anaphase-promoting complex (APC) substrate that accumulates at stalled replication forks. DVC1 recruitment to sites of replication stress...... synthesis (TLS) DNA polymerase η (Pol η) from monoubiquitylated PCNA. DVC1 knockdown enhances UV light-induced mutagenesis, and depletion of human DVC1 or the Caenorhabditis elegans ortholog DVC-1 causes hypersensitivity to replication stress-inducing agents. Our findings establish DVC1 as a DNA damage...

  18. Correlated memory defects and hippocampal dendritic spine loss after acute stress involve corticotropin-releasing hormone signaling.

    Science.gov (United States)

    Chen, Yuncai; Rex, Christopher S; Rice, Courtney J; Dubé, Céline M; Gall, Christine M; Lynch, Gary; Baram, Tallie Z

    2010-07-20

    Stress affects the hippocampus, a brain region crucial for memory. In rodents, acute stress may reduce density of dendritic spines, the location of postsynaptic elements of excitatory synapses, and impair long-term potentiation and memory. Steroid stress hormones and neurotransmitters have been implicated in the underlying mechanisms, but the role of corticotropin-releasing hormone (CRH), a hypothalamic hormone also released during stress within hippocampus, has not been elucidated. In addition, the causal relationship of spine loss and memory defects after acute stress is unclear. We used transgenic mice that expressed YFP in hippocampal neurons and found that a 5-h stress resulted in profound loss of learning and memory. This deficit was associated with selective disruption of long-term potentiation and of dendritic spine integrity in commissural/associational pathways of hippocampal area CA3. The degree of memory deficit in individual mice correlated significantly with the reduced density of area CA3 apical dendritic spines in the same mice. Moreover, administration of the CRH receptor type 1 (CRFR(1)) blocker NBI 30775 directly into the brain prevented the stress-induced spine loss and restored the stress-impaired cognitive functions. We conclude that acute, hours-long stress impairs learning and memory via mechanisms that disrupt the integrity of hippocampal dendritic spines. In addition, establishing the contribution of hippocampal CRH-CRFR(1) signaling to these processes highlights the complexity of the orchestrated mechanisms by which stress impacts hippocampal structure and function.

  19. Reactive oxygen species generation-scavenging and signaling during plant-arbuscular mycorrhizal and Piriformospora indica interaction under stress condition

    OpenAIRE

    Manoj Nath; Deepesh Bhatt; Ram Prasad; Sarvajeet Singh Gill; Naser A. Anjum; Narendra Tuteja

    2016-01-01

    A defined balance between the generation and scavenging of reactive oxygen species (ROS) is essential to utilize ROS as an adaptive defense response of plants under biotic and abiotic stress conditions. Moreover, ROS are not only a major determinant of stress response but also acts as signaling molecule that regulates various cellular processes including plant-microbe interaction. In particular, rhizosphere constitutes the biologically dynamic zone for plant–microbe interactions which forms a...

  20. Pre-earthquake signals – Part I: Deviatoric stresses turn rocks into a source of electric currents

    Directory of Open Access Journals (Sweden)

    F. T. Freund

    2007-09-01

    Full Text Available Earthquakes are feared because they often strike so suddenly. Yet, there are innumerable reports of pre-earthquake signals. Widespread disagreement exists in the geoscience community how these signals can be generated in the Earth's crust and whether they are early warning signs, related to the build-up of tectonic stresses before major seismic events. Progress in understanding and eventually using these signals has been slow because the underlying physical process or processes are basically not understood. This has changed with the discovery that, when igneous or high-grade metamorphic rocks are subjected to deviatoric stress, dormant electronic charge carriers are activated: electrons and defect electrons. The activation increases the number density of mobile charge carriers in the rocks and, hence, their electric conductivity. The defect electrons are associated with the oxygen anion sublattice and are known as positive holes or pholes for short. The boundary between stressed and unstressed rock acts a potential barrier that lets pholes pass but blocks electrons. Therefore, like electrons and ions in an electrochemical battery, the stress-activated electrons and pholes in the "rock battery" have to flow out in different directions. When the circuit is closed, the battery currents can flow. The discovery of such stress-activated currents in crustal rocks has far-reaching implications for understanding pre-earthquake signals.

  1. The Role of Na/K-ATPase Signaling in Oxidative Stress Related to Obesity and Cardiovascular Disease

    Directory of Open Access Journals (Sweden)

    Krithika Srikanthan

    2016-09-01

    Full Text Available Na/K-ATPase has been extensively studied for its ion pumping function, but, in the past several decades, has been identified as a scaffolding and signaling protein. Initially it was found that cardiotonic steroids (CTS mediate signal transduction through the Na/K-ATPase and result in the generation of reactive oxygen species (ROS, which are also capable of initiating the signal cascade. However, in recent years, this Na/K-ATPase/ROS amplification loop has demonstrated significance in oxidative stress related disease states, including obesity, atherosclerosis, heart failure, uremic cardiomyopathy, and hypertension. The discovery of this novel oxidative stress signaling pathway, holds significant therapeutic potential for the aforementioned conditions and others that are rooted in ROS.

  2. Escin activates AKT-Nrf2 signaling to protect retinal pigment epithelium cells from oxidative stress

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    Wang, Kaijun [Eye Center, The 2nd Affiliated Hospital, Medical College of Zhejiang University, Hangzhou (China); Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou (China); Jiang, Yiqian [The First People Hospital of Xiaoshan, Hangzhou (China); Wang, Wei; Ma, Jian [Eye Center, The 2nd Affiliated Hospital, Medical College of Zhejiang University, Hangzhou (China); Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou (China); Chen, Min, E-mail: eyedrchenminzj@163.com [Eye Center, The 2nd Affiliated Hospital, Medical College of Zhejiang University, Hangzhou (China); Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou (China)

    2015-12-25

    Here we explored the anti-oxidative and cytoprotective potentials of escin, a natural triterpene-saponin, against hydrogen peroxide (H{sub 2}O{sub 2}) in retinal pigment epithelium (RPE) cells. We showed that escin remarkably attenuated H{sub 2}O{sub 2}-induced death and apoptosis of established (ARPE-19) and primary murine RPE cells. Meanwhile, ROS production and lipid peroxidation by H{sub 2}O{sub 2} were remarkably inhibited by escin. Escin treatment in RPE cells resulted in NF-E2-related factor 2 (Nrf2) signaling activation, evidenced by transcription of anti-oxidant-responsive element (ARE)-regulated genes, including HO-1, NQO-1 and SRXN-1. Knockdown of Nrf2 through targeted shRNAs/siRNAs alleviated escin-mediated ARE gene transcription, and almost abolished escin-mediated anti-oxidant activity and RPE cytoprotection against H{sub 2}O{sub 2}. Reversely, escin was more potent against H{sub 2}O{sub 2} damages in Nrf2-over-expressed ARPE-19 cells. Further studies showed that escin-induced Nrf2 activation in RPE cells required AKT signaling. AKT inhibitors (LY294002 and perifosine) blocked escin-induced AKT activation, and dramatically inhibited Nrf2 phosphorylation, its cytosol accumulation and nuclear translocation in RPE cells. Escin-induced RPE cytoprotection against H{sub 2}O{sub 2} was also alleviated by the AKT inhibitors. Together, these results demonstrate that escin protects RPE cells from oxidative stress possibly through activating AKT-Nrf2 signaling.

  3. Moderate Stress-Induced Social Bonding and Oxytocin Signaling are Disrupted by Predator Odor in Male Rats.

    Science.gov (United States)

    Muroy, Sandra E; Long, Kimberly L P; Kaufer, Daniela; Kirby, Elizabeth D

    2016-07-01

    In times of stress, social support can serve as a potent buffering mechanism that enhances resilience. In humans, stress can promote protective affiliative interactions and prosocial behavior. Yet, stress also precipitates psychopathologies characterized by social withdrawal such as post-traumatic stress disorder (PTSD) and depression. The factors that drive adaptive vs maladaptive social responses to stress are not yet clear. Rodent studies have focused on pair-bonded, opposite-sex mates and suggest that a variety of stressors can induce social support-like behaviors. However, between same-sex conspecifics-particularly males-stress effects on social bonding are less understood and often associated with aggression and social unrest. We thus sought to investigate if a moderate stressor-3 h of acute immobilization-impacts social-support behaviors differently when experienced in a neutral vs more innately threatening context (ie, paired with predator odor). We found that moderate stress increased social support-seeking behavior in rat cagemates and facilitated long-term sharing of a limited water resource, decreased aggression, and strongly defined dominance ranks (an indicator of home cage stability). In contrast, experiencing the same stressor in the presence of predator odor eliminated the positive behavioral effects of moderate stress. Importantly, hypothalamic oxytocin (OT) signaling increased coincident with stress in a neutral-but not a predator odor-context. Our results define a novel rodent model of divergent stress effects on social affiliation and OT signaling dependent on odor context with particularly strong relevance to stress-related disorders such as PTSD, which are characterized by a disrupted ability to seek and maintain social bonds.

  4. Pro-apoptotic signaling induced by photo-oxidative ER stress is amplified by Noxa, not Bim.

    Science.gov (United States)

    Verfaillie, Tom; van Vliet, Alexander; Garg, Abhishek D; Dewaele, Michael; Rubio, Noemi; Gupta, Sanjeev; de Witte, Peter; Samali, Afshin; Agostinis, Patrizia

    2013-08-30

    Pro-apoptotic signaling instigated by endoplasmic reticulum (ER) stress is tightly governed by the BH3-only proteins like Noxa and Bim, which help trigger apoptosis, in part by inactivating mitochondria protecting proteins like Mcl-1. Bim/Noxa-based pro-apoptotic signaling has been implicated for various ER stressors but not yet for those causing "ER-focused" production of severe oxidative stress. In the present study we found that photo-oxidative (phox)-ER stress induced by hypericin-based photodynamic therapy is associated with activation of PERK (an ER sessile, stress sensor), robust induction of CHOP (a pro-apoptotic transcription factor) and induction of Bim and Noxa (accompanied by an eventual drop in Mcl-1 levels). Interestingly Noxa, but not Bim, contributed toward phox-ER stress induced apoptosis, regulated by PERK in a CHOP-independent, temporally-defined manner. These observations shed further light on complex signaling pathways elicited byphox-ER stress and vouch for directing more investigation toward the role of PERK in cell death governance.

  5. Reactive oxygen species generation-scavenging and signaling during plant-arbuscular mycorrhizal and Piriformospora indica interaction under stress condition

    Directory of Open Access Journals (Sweden)

    Manoj Nath

    2016-10-01

    Full Text Available A defined balance between the generation and scavenging of reactive oxygen species (ROS is essential to utilize ROS as an adaptive defense response of plants under biotic and abiotic stress conditions. Moreover, ROS are not only a major determinant of stress response but also acts as signaling molecule that regulates various cellular processes including plant-microbe interaction. In particular, rhizosphere constitutes the biologically dynamic zone for plant–microbe interactions which forms a mutual link leading to reciprocal signaling in both the partners. Among plant–microbe interactions, symbiotic associations of arbuscular mycorrhizal fungi (AMF and arbuscular mycorrhizal-like fungus especially Piriformospora indica with plants are well known to improve plant growth by alleviating the stress-impacts and consequently enhance the plant fitness. AMF and P. indica colonization mainly enhances ROS-metabolism, maintains ROS-homeostasis, and thereby averts higher ROS-level accrued inhibition in plant cellular processes and plant growth and survival under stressful environments. This article summarizes the major outcomes of the recent reports on the ROS-generation and scavenging and signaling in biotic-abiotic stressed plants with AMF and P. indica colonization. Overall, a detailed exploration of ROS-signature kinetics during plant-AMF/P. indica interaction can help in designing innovative strategies for improving plant health and productivity under stress conditions.

  6. Reactive Oxygen Species Generation-Scavenging and Signaling during Plant-Arbuscular Mycorrhizal and Piriformospora indica Interaction under Stress Condition.

    Science.gov (United States)

    Nath, Manoj; Bhatt, Deepesh; Prasad, Ram; Gill, Sarvajeet S; Anjum, Naser A; Tuteja, Narendra

    2016-01-01

    A defined balance between the generation and scavenging of reactive oxygen species (ROS) is essential to utilize ROS as an adaptive defense response of plants under biotic and abiotic stress conditions. Moreover, ROS are not only a major determinant of stress response but also act as signaling molecule that regulates various cellular processes including plant-microbe interaction. In particular, rhizosphere constitutes the biologically dynamic zone for plant-microbe interactions which forms a mutual link leading to reciprocal signaling in both the partners. Among plant-microbe interactions, symbiotic associations of arbuscular mycorrhizal fungi (AMF) and arbuscular mycorrhizal-like fungus especially Piriformospora indica with plants are well known to improve plant growth by alleviating the stress-impacts and consequently enhance the plant fitness. AMF and P. indica colonization mainly enhances ROS-metabolism, maintains ROS-homeostasis, and thereby averts higher ROS-level accrued inhibition in plant cellular processes and plant growth and survival under stressful environments. This article summarizes the major outcomes of the recent reports on the ROS-generation, scavenging and signaling in biotic-abiotic stressed plants with AMF and P. indica colonization. Overall, a detailed exploration of ROS-signature kinetics during plant-AMF/P. indica interaction can help in designing innovative strategies for improving plant health and productivity under stress conditions.

  7. Heat Stress Modulates Both Anabolic and Catabolic Signaling Pathways Preventing Dexamethasone-Induced Muscle Atrophy In Vitro.

    Science.gov (United States)

    Tsuchida, Wakako; Iwata, Masahiro; Akimoto, Takayuki; Matsuo, Shingo; Asai, Yuji; Suzuki, Shigeyuki

    2017-03-01

    It is generally recognized that synthetic glucocorticoids induce skeletal muscle weakness, and endogenous glucocorticoid levels increase in patients with muscle atrophy. It is reported that heat stress attenuates glucocorticoid-induced muscle atrophy; however, the mechanisms involved are unknown. Therefore, we examined the mechanisms underlying the effects of heat stress against glucocorticoid-induced muscle atrophy using C2C12 myotubes in vitro, focusing on expression of key molecules and signaling pathways involved in regulating protein synthesis and degradation. The synthetic glucocorticoid dexamethasone decreased myotube diameter and protein content, and heat stress prevented the morphological and biochemical glucocorticoid effects. Heat stress also attenuated increases in mRNAs of regulated in development and DNA damage responses 1 (REDD1) and Kruppel-like factor 15 (KLF15). Heat stress recovered the dexamethasone-induced inhibition of PI3K/Akt signaling. These data suggest that changes in anabolic and catabolic signals are involved in heat stress-induced protection against glucocorticoid-induced muscle atrophy. These results have a potentially broad clinical impact because elevated glucocorticoid levels are implicated in a wide range of diseases associated with muscle wasting. J. Cell. Physiol. 232: 650-664, 2017. © 2016 The Authors. Journal of Cellular Physiology published by Wiley Periodicals, Inc. © 2016 The Authors. Journal of Cellular Physiology published by Wiley Periodicals, Inc.

  8. Shear stress induces cell apoptosis via a c-Src-phospholipase D-mTOR signaling pathway in cultured podocytes

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chunfa, E-mail: chunfa.huang@case.edu [Louis Stokes Cleveland Veteran Affairs Medical Center, Case Western Reserve University (United States); Department of Medicine, Case Western Reserve University (United States); Rammelkamp Center for Research and Education, MetroHealth System Campus, Cleveland, OH 44106 (United States); Bruggeman, Leslie A. [Department of Medicine, Case Western Reserve University (United States); Rammelkamp Center for Research and Education, MetroHealth System Campus, Cleveland, OH 44106 (United States); Hydo, Lindsey M. [Louis Stokes Cleveland Veteran Affairs Medical Center, Case Western Reserve University (United States); Miller, R. Tyler [Louis Stokes Cleveland Veteran Affairs Medical Center, Case Western Reserve University (United States); Department of Medicine, Case Western Reserve University (United States); Rammelkamp Center for Research and Education, MetroHealth System Campus, Cleveland, OH 44106 (United States)

    2012-06-10

    The glomerular capillary wall, composed of endothelial cells, the glomerular basement membrane and the podocytes, is continually subjected to hemodynamic force arising from tractional stress due to blood pressure and shear stress due to blood flow. Exposure of glomeruli to abnormal hemodynamic force such as hyperfiltration is associated with glomerular injury and progressive renal disease, and the conversion of mechanical stimuli to chemical signals in the regulation of the process is poorly understood in podocytes. By examining DNA fragmentation, apoptotic nuclear changes and cytochrome c release, we found that shear stress induced cell apoptosis in cultured podocytes. Meanwhile, podocytes exposed to shear stress also stimulated c-Src phosphorylation, phospholipase D (PLD) activation and mammalian target of rapamycin (mTOR) signaling. Using the antibodies against c-Src, PLD{sub 1}, and PLD{sub 2} to perform reciprocal co-immunoprecipitations and in vitro PLD activity assay, our data indicated that c-Src interacted with and activated PLD{sub 1} but not PLD{sub 2}. The inhibition of shear stress-induced c-Src phosphorylation by PP{sub 2} (a specific inhibitor of c-Src kinase) resulted in reduced PLD activity. Phosphatidic acid, produced by shear stress-induced PLD activation, stimulated mTOR signaling, and caused podocyte hypertrophy and apoptosis.

  9. Tanshinol Attenuates the Deleterious Effects of Oxidative Stress on Osteoblastic Differentiation via Wnt/FoxO3a Signaling

    Directory of Open Access Journals (Sweden)

    Yajun Yang

    2013-01-01

    Full Text Available There is now increasing evidence which suggests a pivotal role for oxidative stress in the development and progression of osteoporosis. We confirm herein the protective effects of natural antioxidant Tanshinol against oxidative stress in osteoblastic differentiation and the underlying mechanism. Our results show that hydrogen peroxide (H2O2 leads to accumulation of reactive oxygen species (ROS, decrease in cell viability, cell cycle arrest and apoptosis in a caspase-3-dependent manner, and inhibition of osteoblastic differentiation. Tanshinol reverses these deleterious consequence triggered by oxidative stress. Moreover, under the condition of oxidative stress, Tanshinol suppresses the activation of FoxO3a transcription factor and expressions of its target genes Gadd45a and catalase (CAT and simultaneously counteracts the inhibition of Wnt signalling and expressions of target genes Axin2, alkaline phosphatase (ALP, and Osteoprotegerin (OPG. The findings are further consolidated using FoxO3a siRNA interference and overexpression of Tcf4. The results illustrate that Tanshinol attenuates oxidative stress via down-regulation of FoxO3a signaling, and rescues the decrease of osteoblastic differentiation through upregulation of Wnt signal under oxidative stress. The present findings suggest that the beneficial effects of Tanshinol may be adopted as a novel therapeutic approach in recently recognized conditions of niche targeting osteoporosis.

  10. Replication, recombination, and repair: going for the gold.

    Science.gov (United States)

    Klein, Hannah L; Kreuzer, Kenneth N

    2002-03-01

    DNA recombination is now appreciated to be integral to DNA replication and cell survival. Recombination allows replication to successfully maneuver through the roadblocks of damaged or collapsed replication forks. The signals and controls that permit cells to transition between replication and recombination modes are now being identified.

  11. ER stress in adipocytes inhibits insulin signaling, represses lipolysis, and alters the secretion of adipokines without inhibiting glucose transport.

    Science.gov (United States)

    Xu, L; Spinas, G A; Niessen, M

    2010-08-01

    The endoplasmic reticulum (ER) is the intra-cellular site, where secreted and membrane proteins are synthesized. ER stress and activation of the unfolded protein response (UPR) contribute to insulin resistance and the development of diabetes in obesity. It was shown previously in hepatocytes that the UPR activates c-jun N-terminal kinase (JNK), which phosphorylates insulin receptor substrate (IRS) proteins on serine residues thereby inhibiting insulin signal transduction. Here we describe how ER stress affects insulin signaling and the biological function of adipocytes. In addition to inhibition of IRS we found that ER stress downregulates the expression of the insulin receptor. Concomitantly, insulin-induced activation of Akt/PKB and of ERK1/2 was strongly inhibited. Ectopic expression of IRS1 or IRS2 strongly counteracted the inhibitory effect of ER stress on insulin signaling while pharmacological inhibition of JNK with SP600125 resulted only in a mild improvement. ER stress decreased the secretion of the adipokines adiponectin and leptin, but strongly increased secretion of IL-6. ER stress inhibited expression and insulin-induced phosphorylation of AS160, reduced lipolysis but did not inhibit glucose transport. Finally, supernatants collected from 3T3-L1 adipocytes undergoing ER stress improved or impaired proliferation when used to condition the culture medium of INS-1E beta-cells dependent on the degree of ER stress. It appears that ER stress in adipocytes might initially lead to changes resembling early prediabetic stages, which at least in part support the regulation of systemic energy homeostasis. Copyright Georg Thieme Verlag KG Stuttgart New York.

  12. SIGNALING TO THE P53 TUMOR SUPPRESSOR THROUGH PATHWAYS ACTIVATED BY GENOTOXIC AND NON-GENOTOXIC STRESSES.

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON,C.W.APPELLA,E.

    2002-07-01

    The p53 tumor suppressor is a tetrameric transcription factor that is post-translational modified at {approx}18 different sites by phosphorylation, acetylation, or sumoylation in response to various cellular stress conditions. Specific posttranslational modifications, or groups of modifications, that result from the activation of different stress-induced signaling pathways are thought to modulate p53 activity to regulate cell fate by inducing cell cycle arrest, apoptosis, or cellular senescence. Here we review the posttranslational modifications to p53 and the pathways that produce them in response to both genotoxic and non-genotoxic stresses.

  13. CDIP1-BAP31 Complex Transduces Apoptotic Signals from Endoplasmic Reticulum to Mitochondria under Endoplasmic Reticulum Stress

    Directory of Open Access Journals (Sweden)

    Takushi Namba

    2013-10-01

    Full Text Available Resolved endoplasmic reticulum (ER stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a proapoptotic p53 target, CDIP1, acts as a key signal transducer of ER-stress-mediated apoptosis. We identify B-cell-receptor-associated protein 31 (BAP31 as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 is required for BAP31 cleavage upon ER stress and for BAP31-Bcl-2 association. The recruitment of Bcl-2 to the BAP31-CDIP1 complex, as well as CDIP1-dependent truncated Bid (tBid and caspase-8 activation, contributes to BAX oligomerization. Genetic knockout of CDIP1 in mice leads to impaired response to ER-stress-mediated apoptosis. Altogether, our data demonstrate that the CDIP1/BAP31-mediated regulation of mitochondrial apoptosis pathway represents a mechanism for establishing an ER-mitochondrial crosstalk for ER-stress-mediated apoptosis signaling.

  14. CDIP1-BAP31 complex transduces apoptotic signals from endoplasmic reticulum to mitochondria under endoplasmic reticulum stress.

    Science.gov (United States)

    Namba, Takushi; Tian, Fang; Chu, Kiki; Hwang, So-Young; Yoon, Kyoung Wan; Byun, Sanguine; Hiraki, Masatsugu; Mandinova, Anna; Lee, Sam W

    2013-10-31

    Resolved endoplasmic reticulum (ER) stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a proapoptotic p53 target, CDIP1, acts as a key signal transducer of ER-stress-mediated apoptosis. We identify B-cell-receptor-associated protein 31 (BAP31) as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 is required for BAP31 cleavage upon ER stress and for BAP31-Bcl-2 association. The recruitment of Bcl-2 to the BAP31-CDIP1 complex, as well as CDIP1-dependent truncated Bid (tBid) and caspase-8 activation, contributes to BAX oligomerization. Genetic knockout of CDIP1 in mice leads to impaired response to ER-stress-mediated apoptosis. Altogether, our data demonstrate that the CDIP1/BAP31-mediated regulation of mitochondrial apoptosis pathway represents a mechanism for establishing an ER-mitochondrial crosstalk for ER-stress-mediated apoptosis signaling.

  15. Transcriptomic profiling of soybean in response to high-intensity UV-B irradiation reveals stress defense signaling

    Directory of Open Access Journals (Sweden)

    Min Young Yoon

    2016-12-01

    Full Text Available The depletion of the ozone layer in the stratosphere has led to a dramatic spike in ultraviolet B (UV-B intensity and increased UV-B light levels. The direct absorption of high-intensity UV-B induces complex abiotic stresses in plants, including excessive light exposure, heat, and dehydration. However, UV-B stress signaling mechanisms in plants including soybean (Glycine max [L.] remain poorly understood. Here, we surveyed the overall transcriptional responses of two soybean genotypes, UV-B-sensitive Cheongja 3 and UV-B-resistant Buseok, to continuous UV-B irradiation for 0 (control, 0.5, and 6 h using RNA-seq analysis. Homology analysis using UV-B-related genes from Arabidopsis thaliana revealed differentially expressed genes (DEGs likely involved in UV-B stress responses. Functional classification of the DEGs showed that the categories of immune response, stress defense signaling, and reactive oxygen species (ROS metabolism were over-represented. UV-B-resistant Buseok utilized phosphatidic acid-dependent signaling pathways (based on subsequent reactions of phospholipase C and diacylglycerol kinase rather than phospholipase D in response to UV-B exposure at high fluence rates, and genes involved in its downstream pathways, such as ABA signaling, mitogen-activated protein kinase cascades, and ROS overproduction, were upregulated in this genotype. In addition, the DEGs for TIR-NBS-LRR and heat shock proteins are positively activated. These results suggest that defense mechanisms against UV-B stress at high fluence rates are separate from the photomorphogenic responses utilized by plants to adapt to low-level UV light. Our study provides valuable information for deep understanding of UV-B stress defense mechanisms and for the development of resistant soybean genotypes that survive under high-intensity UV-B stress.

  16. Comparative analysis of seven viral nuclear export signals (NESs reveals the crucial role of nuclear export mediated by the third NES consensus sequence of nucleoprotein (NP in influenza A virus replication.

    Directory of Open Access Journals (Sweden)

    Nopporn Chutiwitoonchai

    Full Text Available The assembly of influenza virus progeny virions requires machinery that exports viral genomic ribonucleoproteins from the cell nucleus. Currently, seven nuclear export signal (NES consensus sequences have been identified in different viral proteins, including NS1, NS2, M1, and NP. The present study examined the roles of viral NES consensus sequences and their significance in terms of viral replication and nuclear export. Mutation of the NP-NES3 consensus sequence resulted in a failure to rescue viruses using a reverse genetics approach, whereas mutation of the NS2-NES1 and NS2-NES2 sequences led to a strong reduction in viral replication kinetics compared with the wild-type sequence. While the viral replication kinetics for other NES mutant viruses were also lower than those of the wild-type, the difference was not so marked. Immunofluorescence analysis after transient expression of NP-NES3, NS2-NES1, or NS2-NES2 proteins in host cells showed that they accumulated in the cell nucleus. These results suggest that the NP-NES3 consensus sequence is mostly required for viral replication. Therefore, each of the hydrophobic (Φ residues within this NES consensus sequence (Φ1, Φ2, Φ3, or Φ4 was mutated, and its viral replication and nuclear export function were analyzed. No viruses harboring NP-NES3 Φ2 or Φ3 mutants could be rescued. Consistent with this, the NP-NES3 Φ2 and Φ3 mutants showed reduced binding affinity with CRM1 in a pull-down assay, and both accumulated in the cell nucleus. Indeed, a nuclear export assay revealed that these mutant proteins showed lower nuclear export activity than the wild-type protein. Moreover, the Φ2 and Φ3 residues (along with other Φ residues within the NP-NES3 consensus were highly conserved among different influenza A viruses, including human, avian, and swine. Taken together, these results suggest that the Φ2 and Φ3 residues within the NP-NES3 protein are important for its nuclear export function

  17. Comparative analysis of seven viral nuclear export signals (NESs) reveals the crucial role of nuclear export mediated by the third NES consensus sequence of nucleoprotein (NP) in influenza A virus replication.

    Science.gov (United States)

    Chutiwitoonchai, Nopporn; Kakisaka, Michinori; Yamada, Kazunori; Aida, Yoko

    2014-01-01

    The assembly of influenza virus progeny virions requires machinery that exports viral genomic ribonucleoproteins from the cell nucleus. Currently, seven nuclear export signal (NES) consensus sequences have been identified in different viral proteins, including NS1, NS2, M1, and NP. The present study examined the roles of viral NES consensus sequences and their significance in terms of viral replication and nuclear export. Mutation of the NP-NES3 consensus sequence resulted in a failure to rescue viruses using a reverse genetics approach, whereas mutation of the NS2-NES1 and NS2-NES2 sequences led to a strong reduction in viral replication kinetics compared with the wild-type sequence. While the viral replication kinetics for other NES mutant viruses were also lower than those of the wild-type, the difference was not so marked. Immunofluorescence analysis after transient expression of NP-NES3, NS2-NES1, or NS2-NES2 proteins in host cells showed that they accumulated in the cell nucleus. These results suggest that the NP-NES3 consensus sequence is mostly required for viral replication. Therefore, each of the hydrophobic (Φ) residues within this NES consensus sequence (Φ1, Φ2, Φ3, or Φ4) was mutated, and its viral replication and nuclear export function were analyzed. No viruses harboring NP-NES3 Φ2 or Φ3 mutants could be rescued. Consistent with this, the NP-NES3 Φ2 and Φ3 mutants showed reduced binding affinity with CRM1 in a pull-down assay, and both accumulated in the cell nucleus. Indeed, a nuclear export assay revealed that these mutant proteins showed lower nuclear export activity than the wild-type protein. Moreover, the Φ2 and Φ3 residues (along with other Φ residues) within the NP-NES3 consensus were highly conserved among different influenza A viruses, including human, avian, and swine. Taken together, these results suggest that the Φ2 and Φ3 residues within the NP-NES3 protein are important for its nuclear export function during viral

  18. Ethylene and Abscisic Acid Signaling Pathways Differentially Influence Tomato Resistance to Combined Powdery Mildew and Salt Stress

    Science.gov (United States)

    Kissoudis, Christos; Seifi, Alireza; Yan, Zhe; Islam, A. T. M. Tanjimul; van der Schoot, Hanneke; van de Wiel, Clemens C. M.; Visser, Richard G. F.; van der Linden, C. G.; Bai, Yuling

    2017-01-01

    There is currently limited knowledge on the role of hormones in plants responses to combinations of abiotic and pathogen stress factors. This study focused on the response of tomato near-isogenic lines (NILs) that carry the Ol-1, ol-2, and Ol-4 loci, conferring resistance to tomato powdery mildew (PM) caused by Oidium neolycopersici, to combined PM and salt stress. These NILs were crossed with the notabilis (ABA-deficient), defenceless1 (JA-deficient), and epinastic (ET overproducer) tomato mutants to investigate possible roles of hormone signaling in response to combined stresses. In the NILs, marker genes for hormonal pathways showed differential expression patterns upon PM infection. The epinastic mutation resulted in breakdown of resistance in NIL-Ol-1 and NIL-ol-2. This was accompanied by reduced callose deposition, and was more pronounced under combined salt stress. The notabilis mutation resulted in H2O2 overproduction and reduced susceptibility to PM in NIL-Ol-1 under combined stress, but lead to higher plant growth reduction under salinity and combined stress. Resistance in NIL-ol-2 was compromised by the notabilis mutation, which was potentially caused by reduction of callose deposition. Under combined stress the compromised resistance in NIL-ol-2 was restored. PM resistance in NIL-Ol-4 remained robust across all mutant and treatment combinations. Hormone signaling is critical to the response to combined stress and PM, in terms of resistance and plant fitness. ABA appears to be at the crossroads of disease susceptibility/senescence and plant performance under combined stress These gained insights can aid in narrowing down targets for improving crop performance under stress combinations. PMID:28119708

  19. Phosphatidic acid produced by phospholipase D promotes RNA replication of a plant RNA virus.

    Directory of Open Access Journals (Sweden)

    Kiwamu Hyodo

    2015-05-01

    Full Text Available Eukaryotic positive-strand RNA [(+RNA] viruses are intracellular obligate parasites replicate using the membrane-bound replicase complexes that contain multiple viral and host components. To replicate, (+RNA viruses exploit host resources and modify host metabolism and membrane organization. Phospholipase D (PLD is a phosphatidylcholine- and phosphatidylethanolamine-hydrolyzing enzyme that catalyzes the production of phosphatidic acid (PA, a lipid second messenger that modulates diverse intracellular signaling in various organisms. PA is normally present in small amounts (less than 1% of total phospholipids, but rapidly and transiently accumulates in lipid bilayers in response to different environmental cues such as biotic and abiotic stresses in plants. However, the precise functions of PLD and PA remain unknown. Here, we report the roles of PLD and PA in genomic RNA replication of a plant (+RNA virus, Red clover necrotic mosaic virus (RCNMV. We found that RCNMV RNA replication complexes formed in Nicotiana benthamiana contained PLDα and PLDβ. Gene-silencing and pharmacological inhibition approaches showed that PLDs and PLDs-derived PA are required for viral RNA replication. Consistent with this, exogenous application of PA enhanced viral RNA replication in plant cells and plant-derived cell-free extracts. We also found that a viral auxiliary replication protein bound to PA in vitro, and that the amount of PA increased in RCNMV-infected plant leaves. Together, our findings suggest that RCNMV hijacks host PA-producing enzymes to replicate.

  20. Mutations in DONSON disrupt replication fork stability and cause microcephalic dwarfism.

    Science.gov (United States)

    Reynolds, John J; Bicknell, Louise S; Carroll, Paula; Higgs, Martin R; Shaheen, Ranad; Murray, Jennie E; Papadopoulos, Dimitrios K; Leitch, Andrea; Murina, Olga; Tarnauskaitė, Žygimantė; Wessel, Sarah R; Zlatanou, Anastasia; Vernet, Audrey; von Kriegsheim, Alex; Mottram, Rachel M A; Logan, Clare V; Bye, Hannah; Li, Yun; Brean, Alexander; Maddirevula, Sateesh; Challis, Rachel C; Skouloudaki, Kassiani; Almoisheer, Agaadir; Alsaif, Hessa S; Amar, Ariella; Prescott, Natalie J; Bober, Michael B; Duker, Angela; Faqeih, Eissa; Seidahmed, Mohammed Zain; Al Tala, Saeed; Alswaid, Abdulrahman; Ahmed, Saleem; Al-Aama, Jumana Yousuf; Altmüller, Janine; Al Balwi, Mohammed; Brady, Angela F; Chessa, Luciana; Cox, Helen; Fischetto, Rita; Heller, Raoul; Henderson, Bertram D; Hobson, Emma; Nürnberg, Peter; Percin, E Ferda; Peron, Angela; Spaccini, Luigina; Quigley, Alan J; Thakur, Seema; Wise, Carol A; Yoon, Grace; Alnemer, Maha; Tomancak, Pavel; Yigit, Gökhan; Taylor, A Malcolm R; Reijns, Martin A M; Simpson, Michael A; Cortez, David; Alkuraya, Fowzan S; Mathew, Christopher G; Jackson, Andrew P; Stewart, Grant S

    2017-04-01

    To ensure efficient genome duplication, cells have evolved numerous factors that promote unperturbed DNA replication and protect, repair and restart damaged forks. Here we identify downstream neighbor of SON (DONSON) as a novel fork protection factor and report biallelic DONSON mutations in 29 individuals with microcephalic dwarfism. We demonstrate that DONSON is a replisome component that stabilizes forks during genome replication. Loss of DONSON leads to severe replication-associated DNA damage arising from nucleolytic cleavage of stalled replication forks. Furthermore, ATM- and Rad3-related (ATR)-dependent signaling in response to replication stress is impaired in DONSON-deficient cells, resulting in decreased checkpoint activity and the potentiation of chromosomal instability. Hypomorphic mutations in DONSON substantially reduce DONSON protein levels and impair fork stability in cells from patients, consistent with defective DNA replication underlying the disease phenotype. In summary, we have identified mutations in DONSON as a common cause of microcephalic dwarfism and established DONSON as a critical replication fork protein required for mammalian DNA replication and genome stability.

  1. Investigations on GSK-3β/NF-kB signaling in stress and stress adaptive behavior in electric foot shock subjected mice.

    Science.gov (United States)

    Bali, Anjana; Jaggi, Amteshwar Singh

    2016-04-01

    The present study was designed to explore the role of GSK-3β and NF-kB signaling in electric foot shock-induced stress and stress adaptation. Mice were subjected to foot shocks of 0.5mA intensity and 1s duration of 1h to produce acute stress. Animals were exposed to the same stressor for 5 days to induce stress adaptation. The behavioral alterations were assessed using the actophotometer, hole board, open field and social interaction tests. The serum corticosterone levels were assessed as a marker of the HPA axis. The levels of total GSK-3β, p-GSK-3β-S9 and p-NF-kB were determined in the hippocampus, frontal cortex and amygdala. Acute electric foot shock stress produced behavioral and biochemical changes; decreased the levels of p-GSK-3β-S9, produced no change in total GSK-3β levels and increased p-NF-kB levels in the brain. However, repeated exposure of foot shock stress restored the behavioral and biochemical changes along with normalization of p-GSK-3β-S9 and p-NF-kB levels. Administration of AR-A01, a selective GSK-3β inhibitor, or diethyldithiocarbamic acid (DDTC), a selective NF-kB inhibitor, diminished acute stress-induced behavioral and biochemical changes. Furthermore, AR-A014418 normalized acute stress-induced alterations in p-GSK-3β-S9 and p-NF-kB levels, however, DDTC selectively restored NF-kB levels without any change in p-GSK-3β-S9 levels. It probably suggests that NF-kB is a downstream mediator of the GSK-3 signaling cascade. It may conclude that acute stress associated decrease in p-GSK-3β-S9 and increase in p-NF-kB levels in the brain contribute in the development of behavioral and biochemical alterations and normalization of GSK-3β/NF-kB signaling may contribute in stress adaptive behavior in response to repeated electric foot shock-subjected mice.

  2. From Hans Selye's discovery of biological stress to the identification of corticotropin-releasing factor signaling pathways: implication in stress-related functional bowel diseases.

    Science.gov (United States)

    Taché, Yvette; Brunnhuber, Stefan

    2008-12-01

    Selye pioneered the concept of biological stress in 1936, culminating in the identification of the corticotropin-releasing factor (CRF) signaling pathways by Vale's group in the last two decades. The characterization of the 41 amino-acid CRF and other peptide members of the mammalian CRF family, urocortin 1, urocortin 2, and urocortin 3, and the cloning of CRF(1) and CRF(2) receptors, which display distinct affinity for CRF ligands, combined with the development of selective CRF receptor antagonists enable us to unravel the importance of CRF(1) receptor in the stress-related endocrine (activation of pituitary-adrenal axis), behavioral (anxiety/depression, altered feeding), autonomic (activation of sympathetic nervous system), and immune responses. The activation of CRF(1) receptors is also one of the key mechanisms through which various stressors impact the gut to stimulate colonic propulsive motor function and to induce hypersensitivity to colorectal distension as shown by the efficacy of the CRF(1) receptor antagonists in blunting these stress-related components. The importance of CRF(1) signaling pathway in the visceral response to stress in experimental animals provided new therapeutic approaches for treatment of functional bowel disorder such as irritable bowel syndrome, a multifactor functional disorder characterized by altered bowel habits and visceral pain, for which stress has been implicated in the pathophysiology and is associated with anxiety-depression in a subset of patients.

  3. MiR-34b-5p Suppresses Melanoma Differentiation-Associated Gene 5 (MDA5) Signaling Pathway to Promote Avian Leukosis Virus Subgroup J (ALV-J)-Infected Cells Proliferaction and ALV-J Replication.

    Science.gov (United States)

    Li, Zhenhui; Luo, Qingbin; Xu, Haiping; Zheng, Ming; Abdalla, Bahareldin Ali; Feng, Min; Cai, Bolin; Zhang, Xiaocui; Nie, Qinghua; Zhang, Xiquan

    2017-01-01

    Avian leukosis virus subgroup J (ALV-J) is an oncogenic retrovirus that has a similar replication cycle to multiple viruses and therefore can be used as a model system for viral entry into host cells. However, there are few reports on the genes or microRNAs (miRNAs) that are responsible for the replication of ALV-J. Our previous miRNA and RNA sequencing data showed that the expression of miR-34b-5p was significantly upregulated in ALV-J-infected chicken spleens compared to non-infected chicken spleens, but melanoma differentiation-associated gene 5 (MDA5) had the opposite expression pattern. In this study, a dual-luciferase reporter assay showed that MDA5 is a direct target of miR-34b-5p. In vitro, overexpression of miR-34b-5p accelerated the proliferation of ALV-J-infected cells by inducing the progression from G2 to S phase and it promoted cell migration. Ectopic expression of MDA5 inhibited ALV-J-infected cell proliferation, the cell cycle and cell migration, and knockdown of MDA5 promoted proliferation, the cell cycle and migration. In addition, during ALV-J infections, MDA5 can detect virus invasion and it triggers the MDA5 signaling pathway. MDA5 overexpression can activate the MDA5 signaling pathway, and thus it can inhibit the mRNA and protein expression of the ALV-J env gene and it can suppress virion secretion. In contrast, in response to the knockdown of MDA5 by small interfering RNA (siRNA) or an miR-34b-5p mimic, genes in the MDA5 signaling pathway were significantly downregulated (P J env and the sample-to-positive ratio of virion in the supernatants were increased. This indicates that miR-34b-5p is able to trigger the MDA5 signaling pathway and affect ALV-J infections. Together, these results suggest that miR-34b-5p targets MDA5 to accelerate the proliferation and migration of ALV-J-infected cells, and it promotes ALV-J replication, via the MDA5 signaling pathway.

  4. Archaeal DNA replication.

    Science.gov (United States)

    Kelman, Lori M; Kelman, Zvi

    2014-01-01

    DNA replication is essential for all life forms. Although the process is fundamentally conserved in the three domains of life, bioinformatic, biochemical, structural, and genetic studies have demonstrated that the process and the proteins involved in archaeal DNA replication are more similar to those in eukaryal DNA replication than in bacterial DNA replication, but have some archaeal-specific features. The archaeal replication system, however, is not monolithic, and there are some differences in the replication process between different species. In this review, the current knowledge of the mechanisms governing DNA replication in Archaea is summarized. The general features of the replication process as well as some of the differences are discussed.

  5. Regular Article: Interaction of ASK1 and the β-Amyloid Precursor Protein in a Stress-Signaling Complex

    Science.gov (United States)

    Galvan, Veronica; Banwait, Surita; Spilman, Patricia; Gorostiza, Olivia F.; Peel, Alyson; Crippen, Danielle; Sidhu, Gurleen; Ichijo, Hidenori; Bredesen, Dale E.

    2007-01-01

    The amyloid precursor protein (APP) is a type I transmembrane protein translocated to neuronal terminals, whose function is still unknown. The C-terminus of APP mediates its interaction with cellular adaptor and signaling proteins, some of which signal to the stress-activated protein kinase (SAPK) pathway. Here we show that ASK1, a MAPKKK that activates two SAPKs, c-Jun N-terminal-kinase (JNK) and p38, is present in a complex containing APP, phospho-MKK6, JIP1 and JNK1. In primary neurons deprived of growth factors, as well as in brains of (FAD)APP-transgenic mice, ASK1 was upregulated in neuronal projections, where it interacted with APP. In non-transgenic brains, ASK1 and APP associated mainly in the ER. Our results indicate that recruitment of ASK1 to stress-signaling complexes assembled with APP may be triggered and enhanced by cellular stress. Thus, ASK1 may be the apical MAPKKK in a signaling complex assembled with APP as a response to stress. PMID:17719230

  6. Interaction of ASK1 and the beta-amyloid precursor protein in a stress-signaling complex.

    Science.gov (United States)

    Galvan, Veronica; Banwait, Surita; Spilman, Patricia; Gorostiza, Olivia F; Peel, Alyson; Ataie, Marina; Crippen, Danielle; Huang, Wei; Sidhu, Gurleen; Ichijo, Hidenori; Bredesen, Dale E

    2007-10-01

    The amyloid precursor protein (APP) is a type I transmembrane protein translocated to neuronal terminals, whose function is still unknown. The C-terminus of APP mediates its interaction with cellular adaptor and signaling proteins, some of which signal to the stress-activated protein kinase (SAPK) pathway. Here we show that ASK1, a MAPKKK that activates two SAPKs, c-Jun N-terminal-kinase (JNK) and p38, is present in a complex containing APP, phospho-MKK6, JIP1 and JNK1. In primary neurons deprived of growth factors, as well as in brains of (FAD)APP-transgenic mice, ASK1 was upregulated in neuronal projections, where it interacted with APP. In non-transgenic brains, ASK1 and APP associated mainly in the ER. Our results indicate that recruitment of ASK1 to stress-signaling complexes assembled with APP may be triggered and enhanced by cellular stress. Thus, ASK1 may be the apical MAPKKK in a signaling complex assembled with APP as a response to stress.

  7. Silica nanoparticles induce endoplasmic reticulum stress response and activate mitogen activated kinase (MAPK signalling

    Directory of Open Access Journals (Sweden)

    Verena Christen

    2016-01-01

    Full Text Available Humans may be exposed to engineered silica nanoparticles (SiO2-NPs but potential adverse effects are poorly understood, in particular in relation to cellular effects and modes of action. Here we studied effects of SiO2-NPs on cellular function in human hepatoma cells (Huh7. Exposure for 24 h to 10 and 50 μg/ml SiO2-NPs led to induction of endoplasmic reticulum (ER stress as demonstrated by transcriptional induction of DNAJB9, GADD34, CHOP, as well as CHOP target genes BIM, CHAC-1, NOXA and PUMA. In addition, CHOP protein was induced. In addition, SiO2-NPs induced an inflammatory response as demonstrated by induction of TNF-α and IL-8. Activation of MAPK signalling was investigated employing a PCR array upon exposure of Huh7 cells to SiO2-NPs. Five of 84 analysed genes, including P21, P19, CFOS, CJUN and KSR1 exhibited significant transcriptional up-regulation, and 18 genes a significant down-regulation. Strongest down-regulation occurred for the proto-oncogene BRAF, MAPK11, one of the four p38 MAPK genes, and for NFATC4. Strong induction of CFOS, CJUN, FRA1 and CMYC was found after exposure to 50 μg/ml SiO2-NPs for 24 h. To analyse for effects derived from up-regulation of TNF-α, Huh7 cells were exposed to SiO2-NPs in the presence of the TNF-α inhibitor sauchinone, which reduced the induction of the TNF-α transcript by about 50%. These data demonstrate that SiO2-NPs induce ER stress, MAPK pathway and lead to inflammatory reaction in human hepatoma cells. Health implications of SiO2-NPs exposure should further be investigated for a risk assessment of these frequently used nanoparticles.

  8. Epigenetic stress responses induce muscle stem-cell ageing by Hoxa9 developmental signals.

    Science.gov (United States)

    Schwörer, Simon; Becker, Friedrich; Feller, Christian; Baig, Ali H; Köber, Ute; Henze, Henriette; Kraus, Johann M; Xin, Beibei; Lechel, André; Lipka, Daniel B; Varghese, Christy S; Schmidt, Manuel; Rohs, Remo; Aebersold, Ruedi; Medina, Kay L; Kestler, Hans A; Neri, Francesco; von Maltzahn, Julia; Tümpel, Stefan; Rudolph, K Lenhard

    2016-12-15

    The functionality of stem cells declines during ageing, and this decline contributes to ageing-associated impairments in tissue regeneration and function. Alterations in developmental pathways have been associated with declines in stem-cell function during ageing, but the nature of this process remains poorly understood. Hox genes are key regulators of stem cells and tissue patterning during embryogenesis with an unknown role in ageing. Here we show that the epigenetic stress response in muscle stem cells (also known as satellite cells) differs between aged and young mice. The alteration includes aberrant global and site-specific induction of active chromatin marks in activated satellite cells from aged mice, resulting in the specific induction of Hoxa9 but not other Hox genes. Hoxa9 in turn activates several developmental pathways and represents a decisive factor that separates satellite cell gene expression in aged mice from that in young mice. The activated pathways include most of the currently known inhibitors of satellite cell function in ageing muscle, including Wnt, TGFβ, JAK/STAT and senescence signalling. Inhibition of aberrant chromatin activation or deletion of Hoxa9 improves satellite cell function and muscle regeneration in aged mice, whereas overexpression of Hoxa9 mimics ageing-associated defects in satellite cells from young mice, which can be rescued by the inhibition of Hoxa9-targeted developmental pathways. Together, these data delineate an altered epigenetic stress response in activated satellite cells from aged mice, which limits satellite cell function and muscle regeneration by Hoxa9-dependent activation of developmental pathways.

  9. Insights for Oxidative Stress and mTOR Signaling in Myocardial Ischemia/Reperfusion Injury under Diabetes

    Directory of Open Access Journals (Sweden)

    Dajun Zhao

    2017-01-01

    Full Text Available Diabetes mellitus (DM displays a high morbidity. The diabetic heart is susceptible to myocardial ischemia/reperfusion (MI/R injury. Impaired activation of prosurvival pathways, endoplasmic reticulum (ER stress, increased basal oxidative state, and decreased antioxidant defense and autophagy may render diabetic hearts more vulnerable to MI/R injury. Oxidative stress and mTOR signaling crucially regulate cardiometabolism, affecting MI/R injury under diabetes. Producing reactive oxygen species (ROS and reactive nitrogen species (RNS, uncoupling nitric oxide synthase (NOS, and disturbing the mitochondrial quality control may be three major mechanisms of oxidative stress. mTOR signaling presents both cardioprotective and cardiotoxic effects on the diabetic heart, which interplays with oxidative stress directly or indirectly. Antihyperglycemic agent metformin and newly found free radicals scavengers, Sirt1 and CTRP9, may serve as promising pharmacological therapeutic targets. In this review, we will focus on the role of oxidative stress and mTOR signaling in the pathophysiology of MI/R injury in diabetes and discuss potential mechanisms and their interactions in an effort to provide some evidence for cardiometabolic targeted therapies for ischemic heart disease (IHD.

  10. mIGF-1/JNK1/SirT1 signaling confers protection against oxidative stress in the heart.

    Science.gov (United States)

    Vinciguerra, Manlio; Santini, Maria Paola; Martinez, Conception; Pazienza, Valerio; Claycomb, William C; Giuliani, Alessandro; Rosenthal, Nadia

    2012-02-01

    Oxidative stress contributes to the pathogenesis of aging-associated heart failure. Among various signaling pathways mediating oxidative stress, the NAD(+) -dependent protein deacetylase SirT1 has been implicated in the protection of heart muscle. Expression of a locally acting insulin-like growth factor-1 (IGF-1) propeptide (mIGF-1) helps the heart to recover from infarct and enhances SirT1 expression in cardiomyocytes (CM) in vitro, exerting protection from hypertrophic and oxidative stresses. To study the role of mIGF-1/SirT1 signaling in vivo, we generated cardiac-specific mIGF-1 transgenic mice in which SirT1 was depleted from adult CM in a tamoxifen-inducible and conditional fashion. Analysis of these mice confirmed that mIGF-1-induced SirT1 activity is necessary to protect the heart from paraquat (PQ)-induced oxidative stress and lethality. In cultured CM, mIGF-1 increases SirT1 expression through a c-Jun NH(2)-terminal protein kinase 1 (JNK1)-dependent signaling mechanism. Thus, mIGF-1 protects the heart from oxidative stress via SirT1/JNK1 activity, suggesting new avenues for cardiac therapy during aging and heart failure.

  11. Insights for Oxidative Stress and mTOR Signaling in Myocardial Ischemia/Reperfusion Injury under Diabetes

    Science.gov (United States)

    Zhao, Dajun

    2017-01-01

    Diabetes mellitus (DM) displays a high morbidity. The diabetic heart is susceptible to myocardial ischemia/reperfusion (MI/R) injury. Impaired activation of prosurvival pathways, endoplasmic reticulum (ER) stress, increased basal oxidative state, and decreased antioxidant defense and autophagy may render diabetic hearts more vulnerable to MI/R injury. Oxidative stress and mTOR signaling crucially regulate cardiometabolism, affecting MI/R injury under diabetes. Producing reactive oxygen species (ROS) and reactive nitrogen species (RNS), uncoupling nitric oxide synthase (NOS), and disturbing the mitochondrial quality control may be three major mechanisms of oxidative stress. mTOR signaling presents both cardioprotective and cardiotoxic effects on the diabetic heart, which interplays with oxidative stress directly or indirectly. Antihyperglycemic agent metformin and newly found free radicals scavengers, Sirt1 and CTRP9, may serve as promising pharmacological therapeutic targets. In this review, we will focus on the role of oxidative stress and mTOR signaling in the pathophysiology of MI/R injury in diabetes and discuss potential mechanisms and their interactions in an effort to provide some evidence for cardiometabolic targeted therapies for ischemic heart disease (IHD).

  12. Chronic stress accelerates ligature-induced periodontitis by suppressing glucocorticoid receptor-α signaling.

    Science.gov (United States)

    Lu, Huaixiu; Xu, Minguang; Wang, Feng; Liu, Shisen; Gu, Jing; Lin, Songshan; Zhao, Lisheng

    2016-03-25

    Periodontitis is a common chronic inflammatory disease. Recent studies have shown that chronic stress (CS) might modulate periodontal disease, but there are few models of CS-induced periodontitis, and the underlying mechanisms are unclear. The present study established a rat model of periodontitis associated with CS induced by nylon thread ligatures. The severity of periodontitis was evaluated in this model by radiographic and pathological examination. The inflammatory reaction indicated by the elevated serum levels of interleukin (IL)-1β, IL-6 and IL-8 was assessed by enzyme-linked immunosorbent assay. Toll-like receptor-4 (TLR4) and glucocorticoid receptor-α (GR-α) expressions were detected by reverse transcriptase-PCR and western blotting. Open-field tests and serum corticosterone were used to evaluate CS. The results showed that CS induced behavioral changes and increased corticosterone levels of the animals with periodontitis. CS stimulation markedly increased alveolar bone loss, periodontal pocket depth and the number of plaques. It also enhanced the inflammatory reaction. These results suggest that CS accelerated the ligature-induced pathological changes associated with periodontitis. Further analysis of the mechanisms involved showed that GR-α expression was significantly downregulated in periodontal tissues of the animals undergoing CS. Blocking GR-α signaling in lipopolysaccharide and corticosteroid-treated human periodontal ligament fibroblast cells in vitro significantly upregulated the expression of p-Akt (protein kinase B) and TLR4, promoted nuclear factor-κB activity and increased levels of IL-1β, IL-6 and IL-8. This research suggests that CS might accelerate the pathological progression of periodontitis by a GR-α signaling-mediated inflammatory response and that this may be a potential therapeutic target for the treatment of periodontal disease, particularly in patients with CS.

  13. Cyclophilin 20-3 relays a 12-oxo-phytodienoic acid signal during stress responsive regulation of cellular redox homeostasis.

    Science.gov (United States)

    Park, Sang-Wook; Li, Wei; Viehhauser, Andrea; He, Bin; Kim, Soonok; Nilsson, Anders K; Andersson, Mats X; Kittle, Joshua D; Ambavaram, Madana M R; Luan, Sheng; Esker, Alan R; Tholl, Dorothea; Cimini, Daniela; Ellerström, Mats; Coaker, Gitta; Mitchell, Thomas K; Pereira, Andy; Dietz, Karl-Josef; Lawrence, Christopher B

    2013-06-04

    The jasmonate family of phytohormones plays central roles in plant development and stress acclimation. However, the architecture of their signaling circuits remains largely unknown. Here we describe a jasmonate family binding protein, cyclophilin 20-3 (CYP20-3), which regulates stress-responsive cellular redox homeostasis. (+)-12-Oxo-phytodienoic acid (OPDA) binding promotes CYP20-3 to form a complex with serine acetyltransferase 1, which triggers the formation of a hetero-oligomeric cysteine synthase complex with O-acetylserine(thiol)lyase B in chloroplasts. The cysteine synthase complex formation then activates sulfur assimilation that leads to increased levels of thiol metabolites and the buildup of cellular reduction potential. The enhanced redox capacity in turn coordinates the expression of a subset of OPDA-responsive genes. Thus, we conclude that CYP20-3 is a key effector protein that links OPDA signaling to amino acid biosynthesis and cellular redox homeostasis in stress responses.

  14. Oma1 Links Mitochondrial Protein Quality Control and TOR Signaling To Modulate Physiological Plasticity and Cellular Stress Responses.

    Science.gov (United States)

    Bohovych, Iryna; Kastora, Stavroula; Christianson, Sara; Topil, Danelle; Kim, Heejeong; Fangman, Teresa; Zhou, You J; Barrientos, Antoni; Lee, Jaekwon; Brown, Alistair J P; Khalimonchuk, Oleh

    2016-09-01

    A network of conserved proteases known as the intramitochondrial quality control (IMQC) system is central to mitochondrial protein homeostasis and cellular health. IMQC proteases also appear to participate in establishment of signaling cues for mitochondrion-to-nucleus communication. However, little is known about this process. Here, we show that in Saccharomyces cerevisiae, inactivation of the membrane-bound IMQC protease Oma1 interferes with oxidative-stress responses through enhanced production of reactive oxygen species (ROS) during logarithmic growth and reduced stress signaling via the TORC1-Rim15-Msn2/Msn4 axis. Pharmacological or genetic prevention of ROS accumulation in Oma1-deficient cells restores this defective TOR signaling. Additionally, inactivation of the Oma1 ortholog in the human fungal pathogen Candida albicans also alters TOR signaling and, unexpectedly, leads to increased resistance to neutrophil killing and virulence in the invertebrate animal model Galleria mellonella Our findings reveal a novel and evolutionarily conserved link between IMQC and TOR-mediated signaling that regulates physiological plasticity and pancellular oxidative-stress responses.

  15. Signaling dynamics of palmitate-induced ER stress responses mediated by ATF4 in HepG2 cells

    Directory of Open Access Journals (Sweden)

    Cho Hyunju

    2013-01-01

    Full Text Available Abstract Background Palmitic acid, the most common saturated free fatty acid, has been implicated in ER (endoplasmic reticulum stress-mediated apoptosis. This lipoapotosis is dependent, in part, on the upregulation of the activating transcription factor-4 (ATF4. To better understand the mechanisms by which palmitate upregulates the expression level of ATF4, we integrated literature information on palmitate-induced ER stress signaling into a discrete dynamic model. The model provides an in silico framework that enables simulations and predictions. The model predictions were confirmed through further experiments in human hepatocellular carcinoma (HepG2 cells and the results were used to update the model and our current understanding of the signaling induced by palmitate. Results The three key things from the in silico simulation and experimental results are: 1 palmitate induces different signaling pathways (PKR (double-stranded RNA-activated protein kinase, PERK (PKR-like ER kinase, PKA (cyclic AMP (cAMP-dependent protein kinase A in a time dependent-manner, 2 both ATF4 and CREB1 (cAMP-responsive element-binding protein 1 interact with the Atf4 promoter to contribute to a prolonged accumulation of ATF4, and 3 CREB1 is involved in ER-stress induced apoptosis upon palmitate treatment, by regulating ATF4 expression and possibly Ca2+ dependent-CaM (calmodulin signaling pathway. Conclusion The in silico model helped to delineate the essential signaling pathways in palmitate-mediated apoptosis.

  16. Chronic chemotherapeutic stress promotes evolution of stemness and WNT/beta-catenin signaling in colorectal cancer cells: implications for clinical use of WNT-signaling inhibitors

    Science.gov (United States)

    Ayadi, Meriam; Bouygues, Anaïs; Ouaret, Djamila; Ferrand, Nathalie; Chouaib, Salem; Thiery, Jean-Paul; Muchardt, Christian; Sabbah, Michèle; Larsen, Annette K

    2015-01-01

    Most solid tumors contain a subfraction of cells with stem/progenitor cell features. Stem cells are naturally chemoresistant suggesting that chronic chemotherapeutic stress may select for cells with increased “stemness”. We carried out a comprehensive molecular and functional analysis of six independently selected colorectal cancer (CRC) cell lines with acquired resistance to three different chemotherapeutic agents derived from two distinct parental cell lines. Chronic drug exposure resulted in complex alterations of stem cell markers that could be classified into three categories: 1) one cell line, HT-29/5-FU, showed increased “stemness” and WNT-signaling, 2) three cell lines showed decreased expression of stem cell markers, decreased aldehyde dehydrogenase activity, attenuated WNT-signaling and lost the capacity to form colonospheres and 3) two cell lines displayed prominent expression of ABC transporters with a heterogeneous response for stem cell markers. While WNT-signaling could be attenuated in the HT-29/5-FU cells by the WNT-signaling inhibitors ICG-001 and PKF-118, this was not accompanied by any selective growth inhibitory effect suggesting that the cytotoxic activity of these compounds is not directly linked to WNT-signaling inhibition. We conclude that classical WNT-signaling inhibitors have toxic off-target activities that need to be addressed for clinical development. PMID:26041882

  17. Salt stress reduces root meristem size by nitric oxide-mediated modulation of auxin accumulation and signaling in Arabidopsis.

    Science.gov (United States)

    Liu, Wen; Li, Rong-Jun; Han, Tong-Tong; Cai, Wei; Fu, Zheng-Wei; Lu, Ying-Tang

    2015-05-01

    The development of the plant root system is highly plastic, which allows the plant to adapt to various environmental stresses. Salt stress inhibits root elongation by reducing the size of the root meristem. However, the mechanism underlying this process remains unclear. In this study, we explored whether and how auxin and nitric oxide (NO) are involved in salt-mediated inhibition of root meristem growth in Arabidopsis (Arabidopsis thaliana) using physiological, pharmacological, and genetic approaches. We found that salt stress significantly reduced root meristem size by down-regulating the expression of PINFORMED (PIN) genes, thereby reducing auxin levels. In addition, salt stress promoted AUXIN RESISTANT3 (AXR3)/INDOLE-3-ACETIC ACID17 (IAA17) stabilization, which repressed auxin signaling during this process. Furthermore, salt stress stimulated NO accumulation, whereas blocking NO production with the inhibitor N(ω)-nitro-l-arginine-methylester compromised the salt-mediated reduction of root meristem size, PIN down-regulation, and stabilization of AXR3/IAA17, indicating that NO is involved in salt-mediated inhibition of root meristem growth. Taken together, these findings suggest that salt stress inhibits root meristem growth by repressing PIN expression (thereby reducing auxin levels) and stabilizing IAA17 (thereby repressing auxin signaling) via increasing NO levels. © 2015 American Society of Plant Biologists. All Rights Reserved.

  18. Clostridium perfringens TpeL Induces Formation of Stress Fibers via Activation of RhoA-ROCK Signaling Pathway.

    Science.gov (United States)

    Nagahama, Masahiro; Ohkubo, Akiko; Kinouchi, Yoshihito; Kobayashi, Keiko; Miyamoto, Kazuaki; Takehara, Masaya; Sakurai, Jun

    2015-01-01

    Clostridium perfringens TpeL belongs to a family of large clostridial glucosylating cytotoxins. TpeL modifies Rac1 and Ras subfamily proteins. Herein we report TpeL-induced formation of stress fibers via RhoA-Rho kinase (ROCK) signaling. A recombinant protein (TpeL1-525) derived from the TpeL N-terminal catalytic domain in the presence of streptolysin O (SLO) induced the formation of actin stress fibers in Madin-Darby canine kidney (MDCK) cells in a dose-dependent manner. The RhoA/ROCK pathway is known to control the formation of stress fibers. We examined the role of the RhoA/ROCK pathway in TpeL-induced formation of stress fibers. TpeL1-525-induced formation of stress fibers was inhibited by the ROCK inhibitor, Y27632 and Rho protein inhibitor, C3 transferase. TpeL1-525 activated RhoA and ROCK in a dose-dependent manner. C3 transferase blocked TpeL1-525-induced activation of RhoA and ROCK whereas Y27632 inhibited TpeL-induced activation of ROCK. These results demonstrate for the first time that TpeL induces the formation of stress fibers by activating the RhoA/ROCK signaling pathway.

  19. Global analysis of WRKY transcription factor superfamily in Setaria identifies potential candidates involved in abiotic stress signalling

    Directory of Open Access Journals (Sweden)

    Mehanathan eMuthamilarasan

    2015-10-01

    Full Text Available Transcription factors (TFs are major players in stress signalling and constitute an integral part of signalling networks. Among the major TFs, WRKY proteins play pivotal roles in regulation of transcriptional reprogramming associated with stress responses. In view of this, genome- and transcriptome-wide identification of WRKY TF family was performed in the C4 model plants, Setaria italica (SiWRKY and S. viridis (SvWRKY, respectively. The study identified 105 SiWRKY and 44 SvWRKY proteins that were computationally analysed for their physicochemical properties. Sequence alignment and phylogenetic analysis classified these proteins into three major groups, namely I, II and III with majority of WRKY proteins belonging to group II (53 SiWRKY and 23 SvWRKY, followed by group III (39 SiWRKY and 11 SvWRKY and group I (10 SiWRKY and 6 SvWRKY. Group II proteins were further classified into 5 subgroups (IIa to IIe based on their phylogeny. Domain analysis showed the presence of WRKY motif and zinc finger-like structures in these proteins along with additional domains in a few proteins. All SiWRKY genes were physically mapped on the S. italica genome and their duplication analysis revealed that 10 and 8 gene pairs underwent tandem and segmental duplications, respectively. Comparative mapping of SiWRKY and SvWRKY genes in related C4 panicoid genomes demonstrated the orthologous relationships between these genomes. In silico expression analysis of SiWRKY and SvWRKY genes showed their differential expression patterns in different tissues and stress conditions. Expression profiling of candidate SiWRKY genes in response to stress (dehydration and salinity and hormone treatments (abscisic acid, salicylic acid and methyl jasmonate suggested the putative involvement of SiWRKY066 and SiWRKY082 in stress and hormone signalling. These genes could be potential candidates for further characterization to delineate their functional roles in abiotic stress signalling.

  20. 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.

  1. Molecular profiling reveals diversity of stress signal transduction cascades in highly penetrant Alzheimer's disease human skin fibroblasts.

    Directory of Open Access Journals (Sweden)

    Graziella Mendonsa

    Full Text Available The serious and growing impact of the neurodegenerative disorder Alzheimer's disease (AD as an individual and societal burden raises a number of key questions: Can a blanket test for Alzheimer's disease be devised forecasting long-term risk for acquiring this disorder? Can a unified therapy be devised to forestall the development of AD as well as improve the lot of present sufferers? Inflammatory and oxidative stresses are associated with enhanced risk for AD. Can an AD molecular signature be identified in signaling pathways for communication within and among cells during inflammatory and oxidative stress, suggesting possible biomarkers and therapeutic avenues? We postulated a unique molecular signature of dysfunctional activity profiles in AD-relevant signaling pathways in peripheral tissues, based on a gain of function in G-protein-coupled bradykinin B2 receptor (BKB2R inflammatory stress signaling in skin fibroblasts from AD patients that results in tau protein Ser hyperphosphorylation. Such a signaling profile, routed through both phosphorylation and proteolytic cascades activated by inflammatory and oxidative stresses in highly penetrant familial monogenic forms of AD, could be informative for pathogenesis of the complex multigenic sporadic form of AD. Comparing stimulus-specific cascades of signal transduction revealed a striking diversity of molecular signaling profiles in AD human skin fibroblasts that express endogenous levels of mutant presenilins PS-1 or PS-2 or the Trisomy 21 proteome. AD fibroblasts bearing the PS-1 M146L mutation associated with highly aggressive AD displayed persistent BKB2R signaling plus decreased ERK activation by BK, correctible by gamma-secretase inhibitor Compound E. Lack of these effects in the homologous PS-2 mutant cells indicates specificity of presenilin gamma-secretase catalytic components in BK signaling biology directed toward MAPK activation. Oxidative stress revealed a JNK-dependent survival

  2. Preconditioning with Azadirachta indica ameliorates cardiorenal dysfunction through reduction in oxidative stress and extracellular signal regulated protein kinase signalling

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    Temidayo Olutayo Omóbòwálé

    2016-10-01

    Conclusions: Together, A. indica and vitamin C prevented IRI-induced cardiorenal dysfunction via reduction in oxidative stress, improvement in antioxidant defence system and increase in the ERK1/2 expressions. Therefore, A. indica can be a useful chemopreventive agent in the prevention and treatment of conditions associated with intestinal ischaemia-reperfusion injury.

  3. TRAIL-Induced Caspase Activation Is a Prerequisite for Activation of the Endoplasmic Reticulum Stress-Induced Signal Transduction Pathways.

    Science.gov (United States)

    Lee, Dae-Hee; Sung, Ki Sa; Guo, Zong Sheng; Kwon, William Taehyung; Bartlett, David L; Oh, Sang Cheul; Kwon, Yong Tae; Lee, Yong J

    2016-05-01

    It is well known that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis can be initially triggered by surface death receptors (the extrinsic pathway) and subsequently amplified through mitochondrial dysfunction (the intrinsic pathway). However, little is known about signaling pathways activated by the TRAIL-induced endoplasmic reticulum (ER) stress response. In this study, we report that TRAIL-induced apoptosis is associated with the endoplasmic reticulum (ER) stress response. Human colorectal carcinoma HCT116 cells were treated with TRAIL and the ER stress-induced signal transduction pathway was investigated. During TRAIL treatment, expression of ER stress marker genes, in particular the BiP (binding immunoglobulin protein) gene, was increased and activation of the PERK (PKR-like ER kinase)-eIF2α (eukaryotic initiation factor 2α)-ATF4 (activating transcription factor 4)-CHOP (CCAAT-enhancer-binding protein homologous protein) apoptotic signal transduction pathway occurred. Experimental data from use of a siRNA (small interfering RNA) technique, caspase inhibitor, and caspase-3-deficient cell line revealed that TRAIL-induced caspase activation is a prerequisite for the TRAIL-induced ER stress response. TRAIL-induced ER stress was triggered by caspase-8-mediated cleavage of BAP31 (B cell receptor-associated protein 31). The involvement of the proapoptotic PERK-CHOP pathway in TRAIL-induced apoptosis was verified by using a PERK knockout (PERK(-/-)) mouse embryo fibroblast (MEF) cell line and a CHOP(-/-) MEF cell line. These results suggest that TRAIL-induced the activation of ER stress response plays a role in TRAIL-induced apoptotic death.

  4. Stress signaling from human mammary epithelial cells contributes to phenotypes of mammographic density.

    Science.gov (United States)

    DeFilippis, Rosa Anna; Fordyce, Colleen; Patten, Kelley; Chang, Hang; Zhao, Jianxin; Fontenay, Gerald V; Kerlikowske, Karla; Parvin, Bahram; Tlsty, Thea D

    2014-09-15

    Telomere malfunction and other types of DNA damage induce an activin A-dependent stress response in mortal nontumorigenic human mammary epithelial cells that subsequently induces desmoplastic-like phenotypes in neighboring fibroblasts. Some characteristics of this fibroblast/stromal response, such as reduced adipocytes and increased extracellular matrix content, are observed not only in tumor tissues but also in disease-free breast tissues at high risk for developing cancer, especially high mammographic density tissues. We found that these phenotypes are induced by repression of the fatty acid translocase CD36, which is seen in desmoplastic and disease-free high mammographic density tissues. In this study, we show that epithelial cells from high mammographic density tissues have more DNA damage signaling, shorter telomeres, increased activin A secretion and an altered DNA damage response compared with epithelial cells from low mammographic density tissues. Strikingly, both telomere malfunction and activin A expression in epithelial cells can repress CD36 expression in adjacent fibroblasts. These results provide new insights into how high mammographic density arises and why it is associated with breast cancer risk, with implications for the definition of novel invention targets (e.g., activin A and CD36) to prevent breast cancer.

  5. Weaning Induced Hepatic Oxidative Stress, Apoptosis, and Aminotransferases through MAPK Signaling Pathways in Piglets

    Science.gov (United States)

    Luo, Zhen; Zhu, Wei; Guo, Qi; Luo, Wenli; Zhang, Jing; Xu, Weina

    2016-01-01

    This study investigated the effects of weaning on the hepatic redox status, apoptosis, function, and the mitogen-activated protein kinase (MAPK) signaling pathways during the first week after weaning in piglets. A total of 12 litters of piglets were weaned at d 21 and divided into the weaning group (WG) and the control group (CG). Six piglets from each group were slaughtered at d 0 (d 20, referred to weaning), d 1, d 4, and d 7 after weaning. Results showed that weaning significantly increased the concentrations of hepatic free radicals H2O2 and NO, malondialdehyde (MDA), and 8-hydroxy-2′-deoxyguanosine (8-OHdG), while significantly decreasing the inhibitory hydroxyl ability (IHA) and glutathione peroxidase (GSH-Px), and altered the level of superoxide dismutase (SOD). The apoptosis results showed that weaning increased the concentrations of caspase-3, caspase-8, caspase-9 and the ratio of Bax/Bcl-2. In addition, aspartate aminotransferase transaminase (AST) and alanine aminotransferase (ALT) in liver homogenates increased after weaning. The phosphorylated JNK and ERK1/2 increased, while the activated p38 initially decreased and then increased. Our results suggested that weaning increased the hepatic oxidative stress and aminotransferases and initiated apoptosis, which may be related to the activated MAPK pathways in postweaning piglets.

  6. Nitric oxide signaling and its role in oxidative stress response in Schizosaccharomyces pombe.

    Science.gov (United States)

    Astuti, Rika Indri; Watanabe, Daisuke; Takagi, Hiroshi

    2016-01-30

    In the fission yeast Schizosaccharomyces pombe, we found that the putative NO dioxygenase SPAC869.02c (named Yhb1) and the S-nitrosoglutathione reductase Fmd2 cooperatively reduced intracellular NO levels as NO-detoxification enzymes. Although both mRNA and protein levels were increased with exogenous NO, their expression patterns were different during growth phases. While treatment with an NO synthase inhibitor in the log phase abrogated both NO production and Yhb1 expression, induction of Fmd2 in the stationary phase was correlated with elevated mitochondrial respiratory chain (MRC) activity, confirmed by the fact that inhibition of MRC complex III led to a decrease in Fmd2 and NO levels. Moreover, NO was localized in the mitochondria in the stationary phase, suggesting that there are two distinctive types of NO signaling in S. pombe. For mitochondria, pretreatment with an NO donor rescued cell growth by repressing generation of reactive oxygen species (ROS) under oxidative stress. DNA microarray analysis revealed that exogenous NO contributes to tolerance to hydrogen peroxide (H2O2) by (i) inhibition of Fe(3+) to Fe(2+) conversion, (ii) upregulation of the H2O2-detoxifying enzymes, and (iii) downregulation of the MRC genes, suggesting that NO plays a pivotal role in the negative feedback system to regulate ROS levels in S. pombe.

  7. DHX36 enhances RIG-I signaling by facilitating PKR-mediated antiviral stress granule formation.

    Directory of Open Access Journals (Sweden)

    Ji-Seung Yoo

    2014-03-01

    Full Text Available RIG-I is a DExD/H-box RNA helicase and functions as a critical cytoplasmic sensor for RNA viruses to initiate antiviral interferon (IFN responses. Here we demonstrate that another DExD/H-box RNA helicase DHX36 is a key molecule for RIG-I signaling by regulating double-stranded RNA (dsRNA-dependent protein kinase (PKR activation, which has been shown to be essential for the formation of antiviral stress granule (avSG. We found that DHX36 and PKR form a complex in a dsRNA-dependent manner. By forming this complex, DHX36 facilitates dsRNA binding and phosphorylation of PKR through its ATPase/helicase activity. Using DHX36 KO-inducible MEF cells, we demonstrated that DHX36 deficient cells showed defect in IFN production and higher susceptibility in RNA virus infection, indicating the physiological importance of this complex in host defense. In summary, we identify a novel function of DHX36 as a critical regulator of PKR-dependent avSG to facilitate viral RNA recognition by RIG-I-like receptor (RLR.

  8. DHX36 enhances RIG-I signaling by facilitating PKR-mediated antiviral stress granule formation.

    Science.gov (United States)

    Yoo, Ji-Seung; Takahasi, Kiyohiro; Ng, Chen Seng; Ouda, Ryota; Onomoto, Koji; Yoneyama, Mitsutoshi; Lai, Janice Ching; Lattmann, Simon; Nagamine, Yoshikuni; Matsui, Tadashi; Iwabuchi, Kuniyoshi; Kato, Hiroki; Fujita, Takashi

    2014-03-01

    RIG-I is a DExD/H-box RNA helicase and functions as a critical cytoplasmic sensor for RNA viruses to initiate antiviral interferon (IFN) responses. Here we demonstrate that another DExD/H-box RNA helicase DHX36 is a key molecule for RIG-I signaling by regulating double-stranded RNA (dsRNA)-dependent protein kinase (PKR) activation, which has been shown to be essential for the formation of antiviral stress granule (avSG). We found that DHX36 and PKR form a complex in a dsRNA-dependent manner. By forming this complex, DHX36 facilitates dsRNA binding and phosphorylation of PKR through its ATPase/helicase activity. Using DHX36 KO-inducible MEF cells, we demonstrated that DHX36 deficient cells showed defect in IFN production and higher susceptibility in RNA virus infection, indicating the physiological importance of this complex in host defense. In summary, we identify a novel function of DHX36 as a critical regulator of PKR-dependent avSG to facilitate viral RNA recognition by RIG-I-like receptor (RLR).

  9. System-wide Analysis of SUMOylation Dynamics in Response to Replication Stress Reveals Novel Small Ubiquitin-like Modified Target Proteins and Acceptor Lysines Relevant for Genome Stability

    DEFF Research Database (Denmark)

    Xiao, Zhenyu; Chang, Jer-Gung; Hendriks, Ivo A;

    2015-01-01

    . Following statistical analysis on five biological replicates, a total of 566 SUMO-2 targets were identified. After 2 hours of Hydroxyurea treatment, 10 proteins were up-regulated for SUMOylation and 2 proteins were down-regulated for SUMOylation, whereas after 24 hours, 35 proteins were up......-regulated for SUMOylation and 13 proteins were down-regulated for SUMOylation. A site-specific approach was used to map over 1,000 SUMO-2 acceptor lysines in target proteins. The methodology is generic and is widely applicable in the ubiquitin field. A large subset of these identified proteins function in one network...... that consists of interacting replication factors, transcriptional regulators, DNA damage response factors including MDC1, ATR-interacting protein ATRIP, the Bloom syndrome protein and the BLM-binding partner RMI1, the crossover junction endonuclease EME1, BRCA1 and CHAF1A. Furthermore, centromeric proteins...

  10. Modeling of [Formula: see text]-mediated calcium signaling in vascular endothelial cells induced by fluid shear stress and ATP.

    Science.gov (United States)

    Li, Long-Fei; Xiang, Cheng; Qin, Kai-Rong

    2015-10-01

    The calcium signaling plays a vital role in flow-dependent vascular endothelial cell (VEC) physiology. Variations in fluid shear stress and ATP concentration in blood vessels can activate dynamic responses of cytosolic-free [Formula: see text] through various calcium channels on the plasma membrane. In this paper, a novel dynamic model has been proposed for transient receptor potential vanilloid 4 [Formula: see text]-mediated intracellular calcium dynamics in VECs induced by fluid shear stress and ATP. Our model includes [Formula: see text] signaling pathways through P2Y receptors and [Formula: see text] channels (indirect mechanism) and captures the roles of the [Formula: see text] compound channels in VEC [Formula: see text] signaling in response to fluid shear stress (direct mechanism). In particular, it takes into account that the [Formula: see text] compound channels are regulated by intracellular [Formula: see text] and [Formula: see text] concentrations. The simulation studies have demonstrated that the dynamic responses of calcium concentration produced by the proposed model correlate well with the existing experimental observations. We also conclude from the simulation studies that endogenously released ATP may play an insignificant role in the process of intracellular [Formula: see text] response to shear stress.

  11. Abscisic acid signals reorientation of polyamine metabolism to orchestrate stress responses via the polyamine exodus pathway in grapevine.

    Science.gov (United States)

    Toumi, Imene; Moschou, Panagiotis N; Paschalidis, Konstantinos A; Bouamama, Badra; Ben Salem-Fnayou, Asma; Ghorbel, Abdel Wahed; Mliki, Ahmed; Roubelakis-Angelakis, Kalliopi A

    2010-05-01

    Polyamines (PAs) have been suggested to be implicated in plant responses to abiotic and biotic stress. Grapevine is a model perennial plant species whose cultivars respond differently to osmotic stress. In this study, we used two cultivars, one sensitive (S) and one tolerant (T) to drought. In adult vines subjected to drought under greenhouse conditions, total PAs were significantly lower in the control T- and higher in the control S-genotype and significantly increased or decreased, respectively, post-treatment. Soluble Put and Spd exhibited the greatest increase on d 8 post-treatment in the T- but not in the S-genotype, which accumulated soluble Spm. Abscisic acid (ABA) was differentially accumulated in T- and S-genotypes under drought conditions, and activated the PA biosynthetic pathway, which in turn was correlated with the differential increases in PA titers. In parallel, polyamine oxidases (PAOs) increased primarily in the S-genotype. ABA at least partially induced PA accumulation and exodus into the apoplast, where they were oxidized by the apoplastic amine oxidases (AOs), producing H2O2, which signaled secondary stress responses. The results here show that the ABA signaling pathway integrates PAs and AOs to regulate the generation of H2O2, which signals further stress responses or the PCD syndrome.

  12. Remodeling of global transcription patterns of Cryptococcus neoformans genes mediated by the stress-activated HOG signaling pathways.

    Science.gov (United States)

    Ko, Young-Joon; Yu, Yeong Man; Kim, Gyu-Bum; Lee, Gir-Won; Maeng, Pil Jae; Kim, Sangsoo; Floyd, Anna; Heitman, Joseph; Bahn, Yong-Sun

    2009-08-01

    The ability to sense and adapt to a hostile host environment is a crucial element for virulence of pathogenic fungi, including Cryptococcus neoformans. These cellular responses are evoked by diverse signaling cascades, including the stress-activated HOG pathway. Despite previous analysis of central components of the HOG pathway, its downstream signaling network is poorly characterized in C. neoformans. Here we performed comparative transcriptome analysis with HOG signaling mutants to explore stress-regulated genes and their correlation with the HOG pathway in C. neoformans. In this study, we not only provide important insights into remodeling patterns of global gene expression for counteracting external stresses but also elucidate novel characteristics of the HOG pathway in C. neoformans. First, inhibition of the HOG pathway increases expression of ergosterol biosynthesis genes and cellular ergosterol content, conferring a striking synergistic antifungal activity with amphotericin B and providing an excellent opportunity to develop a novel therapeutic method for treatment of cryptococcosis. Second, a number of cadmium-sensitive genes are differentially regulated by the HOG pathway, and their mutation causes resistance to cadmium. Finally, we have discovered novel stress defense and HOG-dependent genes, which encode a sodium/potassium efflux pump, protein kinase, multidrug transporter system, and elements of the ubiquitin-dependent system.

  13. Evidence for a Role of Adolescent Endocannabinoid Signaling in Regulating HPA Axis Stress Responsivity and Emotional Behavior Development.

    Science.gov (United States)

    Lee, Tiffany T-Y; Gorzalka, Boris B

    2015-01-01

    Adolescence is a period characterized by many distinct physical, behavioral, and neural changes during the transition from child- to adulthood. In particular, adolescent neural changes often confer greater plasticity and flexibility, yet with this comes the potential for heightened vulnerability to external perturbations such as stress exposure or recreational drug use. There is substantial evidence to suggest that factors such as adolescent stress exposure have longer lasting and sometimes more deleterious effects on an organism than stress exposure during adulthood. Moreover, the adolescent neuroendocrine response to stress exposure is different from that of adults, suggesting that further maturation of the adolescent hypothalamic-pituitary-adrenal (HPA) axis is required. The endocannabinoid (eCB) system is a potential candidate underlying these age-dependent differences given that it is an important regulator of the adult HPA axis and neuronal development. Therefore, this review will focus on (1) the functionality of the adolescent HPA axis, (2) eCB regulation of the adult HPA axis, (3) dynamic changes in eCB signaling during the adolescent period, (4) the effects of adolescent stress exposure on the eCB system, and (5) modulation of HPA axis activity and emotional behavior by adolescent cannabinoid treatment. Collectively, the emerging picture suggests that the eCB system mediates interactions between HPA axis stress responsivity, emotionality, and maturational stage. These findings may be particularly relevant to our understanding of the development of affective disorders and the risks of adolescent cannabis consumption on emotional health and stress responsivity.

  14. Glutaredoxin Desensitizes Lens to Oxidative Stress by Connecting and Integrating Specific Signaling and Transcriptional Regulation for Antioxidant Response

    Directory of Open Access Journals (Sweden)

    Qi Fan

    2016-10-01

    Full Text Available Background/Aims: Oxidative stress plays a critical role in the development of cataracts, and glutaredoxins (Grxs play a major protective role against oxidative stress in the lens. This study aimed to reveal the global regulatory network of Grx1. Methods: Stable isotope labeling by amino acids in cell culture (SILAC was used in a proteome-wide quantitative approach to identify the Grx1 regulatory signaling cascades at a subcellular resolution in response to oxidative stress. Results: A total of 1,291 proteins were identified to be differentially expressed, which were further categorized into a variety of signaling cascades including redox regulation, apoptosis, cell cycle control, glucose metabolism, protein synthesis, DNA damage response, protein folding, proteasome and others. Thirteen key signaling node molecules representing each pathway were verified. Notably, the subunits of proteasome complexes, which play a pivotal role in preventing cytotoxicity via the degradation of oxidized proteins, were highly enriched by Grx1. By data-dependent network analysis, we found global functional links among these signaling pathways which elucidate how Grx1 integrates the operation of these regulatory networks in an interconnected way for H2O2-induced response. Conclusion: Our data provide a system-wide insight into the function of Grx1 and provide a basis for further mechanistic investigation of Grx1 in antioxidant responses in the lens.

  15. Diacylglycerol lipase regulates lifespan and oxidative stress response by inversely modulating TOR signaling in Drosophila and C. elegans.

    Science.gov (United States)

    Lin, Yen-Hung; Chen, Yi-Chun; Kao, Tzu-Yu; Lin, Yi-Chun; Hsu, Tzu-En; Wu, Yi-Chun; Ja, William W; Brummel, Theodore J; Kapahi, Pankaj; Yuh, Chiou-Hwa; Yu, Lin-Kwei; Lin, Zhi-Han; You, Ru-Jing; Jhong, Yi-Ting; Wang, Horng-Dar

    2014-08-01

    Target of rapamycin (TOR) signaling is a nutrient-sensing pathway controlling metabolism and lifespan. Although TOR signaling can be activated by a metabolite of diacylglycerol (DAG), phosphatidic acid (PA), the precise genetic mechanism through which DAG metabolism influences lifespan remains unknown. DAG is metabolized to either PA via the action of DAG kinase or 2-arachidonoyl-sn-glycerol by diacylglycerol lipase (DAGL). Here, we report that in Drosophila and Caenorhabditis elegans, overexpression of diacylglycerol lipase (DAGL/inaE/dagl-1) or knockdown of diacylglycerol kinase (DGK/rdgA/dgk-5) extends lifespan and enhances response to oxidative stress. Phosphorylated S6 kinase (p-S6K) levels are reduced following these manipulations, implying the involvement of TOR signaling. Conversely, DAGL/inaE/dagl-1 mutants exhibit shortened lifespan, reduced tolerance to oxidative stress, and elevated levels of p-S6K. Additional results from genetic interaction studies are consistent with the hypothesis that DAG metabolism interacts with TOR and S6K signaling to affect longevity and oxidative stress resistance. These findings highlight conserved metabolic and genetic pathways that regulate aging.

  16. Stress-Immune-Growth Interactions: Cortisol Modulates Suppressors of Cytokine Signaling and JAK/STAT Pathway in Rainbow Trout Liver.

    Directory of Open Access Journals (Sweden)

    Anju M Philip

    Full Text Available Chronic stress is a major factor in the poor growth and immune performance of salmonids in aquaculture. However, the molecular mechanisms linking stress effects to growth and immune dysfunction is poorly understood. The suppressors of cytokine signaling (SOCS, a family of genes involved in the inhibition of JAK/STAT pathway, negatively regulates growth hormone and cytokine signaling, but their role in fish is unclear. Here we tested the hypothesis that cortisol modulation of SOCS gene expression is a key molecular mechanism leading to growth and immune suppression in response to stress in fish. Exposure of rainbow trout (Oncorhynchus mykiss liver slices to cortisol, mimicking stress level, upregulated SOCS-1 and SOCS-2 mRNA abundance and this response was abolished by the glucocorticoid receptor antagonist mifepristone. Bioinformatics analysis confirmed the presence of putative glucocorticoid response elements in rainbow trout SOCS-1 and SOCS-2 promoters. Prior cortisol treatment suppressed acute growth hormone (GH-stimulated IGF-1 mRNA abundance in trout liver and this involved a reduction in STAT5 phosphorylation and lower total JAK2 protein expression. Prior cortisol treatment also suppressed lipopolysaccharide (LPS-induced IL-6 but not IL-8 transcript levels; the former but not the latter cytokine expression is via JAK/STAT phosphorylation. LPS treatment reduced GH signaling, but this was associated with the downregulation of GH receptors and not due to the upregulation of SOCS transcript levels by this endotoxin. Collectively, our results suggest that upregulation of SOCS-1 and SOCS-2 transcript levels by cortisol, and the associated reduction in JAK/STAT signaling pathway, may be a novel mechanism leading to growth reduction and immune suppression during stress in trout.

  17. Morin Attenuates Ovalbumin-Induced Airway Inflammation by Modulating Oxidative Stress-Responsive MAPK Signaling

    Directory of Open Access Journals (Sweden)

    Yuan Ma

    2016-01-01

    abolished by morin, implying that ROS/MAPK signaling contributes to the relief of airway inflammation. Our findings indicate for the first time that morin alleviates airway inflammation in chronic asthma, which probably occurs via the oxidative stress-responsive MAPK pathway, highlighting a novel profile of morin as a potent agent for asthma management.

  18. Skeletal muscle and hepatic insulin signaling is maintained in heat-stressed lactating Holstein cows.

    Science.gov (United States)

    Xie, G; Cole, L C; Zhao, L D; Skrzypek, M V; Sanders, S R; Rhoads, M L; Baumgard, L H; Rhoads, R P