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Sample records for cell death regulators

  1. The regulation of apoptotic cell death

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    G.P. Amarante-Mendes

    1999-09-01

    Full Text Available Apoptosis is a fundamental biological phenomenon in which the death of a cell is genetically and biochemically regulated. Different molecules are involved in the regulation of the apoptotic process. Death receptors, coupled to distinct members of the caspases as well as other adapter molecules, are involved in the initiation of the stress signals (The Indictment. Members of the Bcl-2 family control at the mitochondrial level the decision between life and death (The Judgement. The effector caspases are responsible for all morphological and biochemical changes related to apoptosis including the "eat-me" signals perceived by phagocytes and neighboring cells (The Execution. Finally, apoptosis would have little biological significance without the recognition and removal of the dying cells (The Burial.

  2. The regulation of apoptotic cell death

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    Amarante-Mendes G.P.

    1999-01-01

    Full Text Available Apoptosis is a fundamental biological phenomenon in which the death of a cell is genetically and biochemically regulated. Different molecules are involved in the regulation of the apoptotic process. Death receptors, coupled to distinct members of the caspases as well as other adapter molecules, are involved in the initiation of the stress signals (The Indictment. Members of the Bcl-2 family control at the mitochondrial level the decision between life and death (The Judgement. The effector caspases are responsible for all morphological and biochemical changes related to apoptosis including the "eat-me" signals perceived by phagocytes and neighboring cells (The Execution. Finally, apoptosis would have little biological significance without the recognition and removal of the dying cells (The Burial.

  3. Mitochondria: Regulators of Cell Death and Survival

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    David J. Granville

    2002-01-01

    Full Text Available The past 5 years has seen an intense surge in research devoted toward understanding the critical role of mitochondria in the regulation of cell death. Apoptosis can be initiated by a wide array of stimuli, inducing multiple signaling pathways that, for the most part, converge at the mitochondrion. Although classically considered the powerhouses of the cell, it is now understood that mitochondria are also “gatekeepers” that ultimately determine the fate of the cell. The mitochondrial decision as to whether a cell lives or dies is complex, involving protein-protein interactions, ionic changes, reactive oxygen species, and other mechanisms that require further elucidation. Once the death process is initiated, mitochondria undergo conformational changes, resulting in the release of cytochrome c (cyt c, caspases, endonucleases, and other factors leading to the onset and execution of apoptosis. The present review attempts to outline the complex milieu of events regulating the mitochondrial commitment to and processes involved in the implementation of the executioner phase of apoptotic cell death.

  4. Protein kinase D regulates cell death pathways in experimental pancreatitis

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    Jingzhen eYuan

    2012-03-01

    Full Text Available Inflammation and acinar cell necrosis are two major pathological responses of acute pancreatitis, a serious disorder with no current therapies directed to its molecular pathogenesis. Serine/threonine protein kinase D family, which includes PKD/PKD1, PKD2, and PKD3, has been increasingly implicated in the regulation of multiple physiological and pathophysiological effects. We recently reported that PKD/PKD1, the predominant PKD isoform expressed in rat pancreatic acinar cells, mediates early events of pancreatitis including NF-kappaB activation and inappropriate intracellular digestive enzyme activation. In current studies, we investigated the role and mechanisms of PKD/PKD1 in the regulation of necrosis in pancreatic acinar cells by using two novel small molecule PKD inhibitors CID755673 and CRT0066101 and molecular approaches in in vitro and in vivo experimental models of acute pancreatitis. Our results demonstrated that both CID755673 and CRT0066101 are PKD-specific inhibitors and that PKD/PKD1 inhibition by either the chemical inhibitors or specific PKD/PKD1 siRNAs attenuated necrosis while promoting apoptosis induced by pathological doses of cholecystokinin-octapeptide (CCK in pancreatic acinar cells. Conversely, upregulation of PKD expression in pancreatic acinar cells increased necrosis and decreased apoptosis. We further showed that PKD/PKD1 regulated several key cell death signals including inhibitors of apoptotic proteins (IAPs, caspases, receptor-interacting protein kinase 1 (RIP1 to promote necrosis. PKD/PKD1 inhibition by CID755673 significantly ameliorated necrosis and severity of pancreatitis in an in vivo experimental model of acute pancreatitis. Thus, our studies indicate that PKD/PKD1 is a key mediator of necrosis in acute pancreatitis and that PKD/PKD1 may represent a potential therapeutic target in acute pancreatitis.

  5. VMP1 related autophagy and apoptosis in colorectal cancer cells: VMP1 regulates cell death

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    Qian, Qinyi [Department of Ultrasonograph, Changshu No. 2 People’s Hospital, Changshu (China); Zhou, Hao; Chen, Yan [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Shen, Chenglong [Department of General Surgery, Changshu No. 2 People’s Hospital, Changshu (China); He, Songbing; Zhao, Hua; Wang, Liang [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Wan, Daiwei, E-mail: 372710369@qq.com [Department of Hepatobiliary Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou (China); Gu, Wen, E-mail: 505339704@qq.com [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China)

    2014-01-17

    Highlights: •This research confirmed VMP1 as a regulator of autophagy in colorectal cancer cell lines. •We proved the pro-survival role of VMP1-mediated autophagy in colorectal cancer cell lines. •We found the interaction between VMP1 and BECLIN1 also existing in colorectal cancer cell lines. -- Abstract: Vacuole membrane protein 1 (VMP1) is an autophagy-related protein and identified as a key regulator of autophagy in recent years. In pancreatic cell lines, VMP1-dependent autophagy has been linked to positive regulation of apoptosis. However, there are no published reports on the role of VMP1 in autophagy and apoptosis in colorectal cancers. Therefore, to address this gap of knowledge, we decided to interrogate regulation of autophagy and apoptosis by VMP1. We have studied the induction of autophagy by starvation and rapamycin treatment in colorectal cell lines using electron microscopy, immunofluorescence, and immunoblotting. We found that starvation-induced autophagy correlated with an increase in VMP1 expression, that VMP1 interacted with BECLIN1, and that siRNA mediated down-regulation of VMP1-reduced autophagy. Next, we examined the relationship between VMP1-dependent autophagy and apoptosis and found that VMP1 down-regulation sensitizes cells to apoptosis and that agents that induce apoptosis down-regulate VMP1. In conclusion, similar to its reported role in other cell types, VMP1 is an important regulator of autophagy in colorectal cell lines. However, in contrast to its role in pancreatic cell lines, in colorectal cancer cells, VMP1-dependent autophagy appears to be pro-survival rather than pro-cell death.

  6. Epigenetic regulation of motor neuron cell death through DNA methylation.

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    Chestnut, Barry A; Chang, Qing; Price, Ann; Lesuisse, Catherine; Wong, Margaret; Martin, Lee J

    2011-11-16

    DNA methylation is an epigenetic mechanism for gene silencing engaged by DNA methyltransferase (Dnmt)-catalyzed methyl group transfer to cytosine residues in gene-regulatory regions. It is unknown whether aberrant DNA methylation can cause neurodegeneration. We tested the hypothesis that Dnmts can mediate neuronal cell death. Enforced expression of Dnmt3a induced degeneration of cultured NSC34 cells. During apoptosis of NSC34 cells induced by camptothecin, levels of Dnmt1 and Dnmt3a increased fivefold and twofold, respectively, and 5-methylcytosine accumulated in nuclei. Truncation mutation of the Dnmt3a catalytic domain and Dnmt3a RNAi blocked apoptosis of cultured neurons. Inhibition of Dnmt catalytic activity with RG108 and procainamide protected cultured neurons from excessive DNA methylation and apoptosis. In vivo, Dnmt1 and Dnmt3a are expressed differentially during mouse brain and spinal cord maturation and in adulthood when Dnmt3a is abundant in synapses and mitochondria. Dnmt1 and Dnmt3a are expressed in motor neurons of adult mouse spinal cord, and, during their apoptosis induced by sciatic nerve avulsion, nuclear and cytoplasmic 5-methylcytosine immunoreactivity, Dnmt3a protein levels and Dnmt enzyme activity increased preapoptotically. Inhibition of Dnmts with RG108 blocked completely the increase in 5-methycytosine and the apoptosis of motor neurons in mice. In human amyotrophic lateral sclerosis (ALS), motor neurons showed changes in Dnmt1, Dnmt3a, and 5-methylcytosine similar to experimental models. Thus, motor neurons can engage epigenetic mechanisms to drive apoptosis, involving Dnmt upregulation and increased DNA methylation. These cellular mechanisms could be relevant to human ALS pathobiology and disease treatment.

  7. TOR regulates cell death induced by telomere dysfunction in budding yeast.

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    Haiyan Qi

    Full Text Available Telomere dysfunction is known to induce growth arrest (senescence and cell death. However, the regulation of the senescence-death process is poorly understood. Here using a yeast dysfunctional telomere model cdc13-1, which carries a temperature sensitive-mutant telomere binding protein Cdc13p, we demonstrate that inhibition of TOR (Target of Rapamycin, a central regulator of nutrient pathways for cell growth, prevents cell death, but not growth arrest, induced by inactivation of Cdc13-1p. This function of TOR is novel and separable from its G1 inhibition function, and not associated with alterations in the telomere length, the amount of G-tails, and the telomere position effect (TPE in cdc13-1 cells. Furthermore, antioxidants were also shown to prevent cell death initiated by inactivation of cdc13-1. Moreover, inhibition of TOR was also shown to prevent cell death induced by inactivation of telomerase in an est1 mutant. Interestingly, rapamycin did not prevent cell death induced by DNA damaging agents such as etoposide and UV. In the aggregate, our results suggest that the TOR signaling pathway is specifically involved in the regulation of cell death initiated by telomere dysfunction.

  8. Multiple mediators of plant programmed cell death : interplay of conserved cell death mechanisms and plant-specific regulators

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    Hoeberichts, F.A.; Woltering, E.J.

    2002-01-01

    Programmed cell death (PCD) is a process aimed at the removal of redundant, misplaced, or damaged cells and it is essential to the development and maintenance of multicellular organisms. In contrast to the relatively well-described cell death pathway in animals, often referred to as apoptosis,

  9. Calcium regulates cell death in cancer: Roles of the mitochondria and mitochondria-associated membranes (MAMs).

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    Danese, Alberto; Patergnani, Simone; Bonora, Massimo; Wieckowski, Mariusz R; Previati, Maurizio; Giorgi, Carlotta; Pinton, Paolo

    2017-08-01

    Until 1972, the term 'apoptosis' was used to differentiate the programmed cell death that naturally occurs in organismal development from the acute tissue death referred to as necrosis. Many studies on cell death and programmed cell death have been published and most are, at least to some degree, related to cancer. Some key proteins and molecular pathways implicated in cell death have been analyzed, whereas others are still being actively researched; therefore, an increasing number of cellular compartments and organelles are being implicated in cell death and cancer. Here, we discuss the mitochondria and subdomains of the endoplasmic reticulum (ER) that interact with mitochondria, the mitochondria-associated membranes (MAMs), which have been identified as critical hubs in the regulation of cell death and tumor growth. MAMs-dependent calcium (Ca 2+ ) release from the ER allows selective Ca 2+ uptake by the mitochondria. The perturbation of Ca 2+ homeostasis in cancer cells is correlated with sustained cell proliferation and the inhibition of cell death through the modulation of Ca 2+ signaling. This article is part of a Special Issue entitled Mitochondria in Cancer, edited by Giuseppe Gasparre, Rodrigue Rossignol and Pierre Sonveaux. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Cullin-4 regulates Wingless and JNK signaling-mediated cell death in the Drosophila eye.

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    Tare, Meghana; Sarkar, Ankita; Bedi, Shimpi; Kango-Singh, Madhuri; Singh, Amit

    2016-12-29

    In all multicellular organisms, the fundamental processes of cell proliferation and cell death are crucial for growth regulation during organogenesis. Strict regulation of cell death is important to maintain tissue homeostasis by affecting processes like regulation of cell number, and elimination of unwanted/unfit cells. The developing Drosophila eye is a versatile model to study patterning and growth, where complex signaling pathways regulate growth and cell survival. However, the molecular mechanisms underlying regulation of these processes is not fully understood. In a gain-of-function screen, we found that misexpression of cullin-4 (cul-4), an ubiquitin ligase, can rescue reduced eye mutant phenotypes. Previously, cul-4 has been shown to regulate chromatin remodeling, cell cycle and cell division. Genetic characterization of cul-4 in the developing eye revealed that loss-of-function of cul-4 exhibits a reduced eye phenotype. Analysis of twin-spots showed that in comparison with their wild-type counterparts, the cul-4 loss-of-function clones fail to survive. Here we show that cul-4 clones are eliminated by induction of cell death due to activation of caspases. Aberrant activation of signaling pathways is known to trigger cell death in the developing eye. We found that Wingless (Wg) and c-Jun-amino-terminal-(NH2)-Kinase (JNK) signaling are ectopically induced in cul-4 mutant clones, and these signals co-localize with the dying cells. Modulating levels of Wg and JNK signaling by using agonists and antagonists of these pathways demonstrated that activation of Wg and JNK signaling enhances cul-4 mutant phenotype, whereas downregulation of Wg and JNK signaling rescues the cul-4 mutant phenotypes of reduced eye. Here we present evidences to demonstrate that cul-4 is involved in restricting Wg signaling and downregulation of JNK signaling-mediated cell death during early eye development. Overall, our studies provide insights into a novel role of cul-4 in promoting cell

  11. The phytoalexin resveratrol regulates the initiation of hypersensitive cell death in Vitis cell.

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    Chang, Xiaoli; Heene, Ernst; Qiao, Fei; Nick, Peter

    2011-01-01

    Resveratrol is a major phytoalexin produced by plants in response to various stresses and promotes disease resistance. The resistance of North American grapevine Vitis rupestris is correlated with a hypersensitive reaction (HR), while susceptible European Vitis vinifera cv. 'Pinot Noir' does not exhibit HR, but expresses basal defence. We have shown previously that in cell lines derived from the two Vitis species, the bacterial effector Harpin induced a rapid and sensitive accumulation of stilbene synthase (StSy) transcripts, followed by massive cell death in V. rupestris. In the present work, we analysed the function of the phytoalexin resveratrol, the product of StSy. We found that cv. 'Pinot Noir' accumulated low resveratrol and its glycoside trans-piceid, whereas V. rupestris produced massive trans-resveratrol and the toxic oxidative δ-viniferin, indicating that the preferred metabolitism of resveratrol plays role in Vitis resistance. Cellular responses to resveratrol included rapid alkalinisation, accumulation of pathogenesis-related protein 5 (PR5) transcripts, oxidative burst, actin bundling, and cell death. Microtubule disruption and induction of StSy were triggered by Harpin, but not by resveratrol. Whereas most responses proceeded with different amplitude for the two cell lines, the accumulation of resveratrol, and the competence for resveratrol-induced oxidative burst differed in quality. The data lead to a model, where resveratrol, in addition to its classical role as antimicrobial phytoalexin, represents an important regulator for initiation of HR-related cell death.

  12. The phytoalexin resveratrol regulates the initiation of hypersensitive cell death in Vitis cell.

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    Xiaoli Chang

    Full Text Available Resveratrol is a major phytoalexin produced by plants in response to various stresses and promotes disease resistance. The resistance of North American grapevine Vitis rupestris is correlated with a hypersensitive reaction (HR, while susceptible European Vitis vinifera cv. 'Pinot Noir' does not exhibit HR, but expresses basal defence. We have shown previously that in cell lines derived from the two Vitis species, the bacterial effector Harpin induced a rapid and sensitive accumulation of stilbene synthase (StSy transcripts, followed by massive cell death in V. rupestris. In the present work, we analysed the function of the phytoalexin resveratrol, the product of StSy. We found that cv. 'Pinot Noir' accumulated low resveratrol and its glycoside trans-piceid, whereas V. rupestris produced massive trans-resveratrol and the toxic oxidative δ-viniferin, indicating that the preferred metabolitism of resveratrol plays role in Vitis resistance. Cellular responses to resveratrol included rapid alkalinisation, accumulation of pathogenesis-related protein 5 (PR5 transcripts, oxidative burst, actin bundling, and cell death. Microtubule disruption and induction of StSy were triggered by Harpin, but not by resveratrol. Whereas most responses proceeded with different amplitude for the two cell lines, the accumulation of resveratrol, and the competence for resveratrol-induced oxidative burst differed in quality. The data lead to a model, where resveratrol, in addition to its classical role as antimicrobial phytoalexin, represents an important regulator for initiation of HR-related cell death.

  13. TAK1 regulates caspase 8 activation and necroptotic signaling via multiple cell death checkpoints.

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    Guo, Xiaoyun; Yin, Haifeng; Chen, Yi; Li, Lei; Li, Jing; Liu, Qinghang

    2016-09-29

    Necroptosis has emerged as a new form of programmed cell death implicated in a number of pathological conditions such as ischemic injury, neurodegenerative disease, and viral infection. Recent studies indicate that TGFβ-activated kinase 1 (TAK1) is nodal regulator of necroptotic cell death, although the underlying molecular regulatory mechanisms are not well defined. Here we reported that TAK1 regulates necroptotic signaling as well as caspase 8-mediated apoptotic signaling through both NFκB-dependent and -independent mechanisms. Inhibition of TAK1 promoted TNFα-induced cell death through the induction of RIP1 phosphorylation/activation and necrosome formation. Further, inhibition of TAK1 triggered two caspase 8 activation pathways through the induction of RIP1-FADD-caspase 8 complex as well as FLIP cleavage/degradation. Mechanistically, our data uncovered an essential role for the adaptor protein TNF receptor-associated protein with death domain (TRADD) in caspase 8 activation and necrosome formation triggered by TAK1 inhibition. Moreover, ablation of the deubiqutinase CYLD prevented both apoptotic and necroptotic signaling induced by TAK1 inhibition. Finally, blocking the ubiquitin-proteasome pathway prevented the degradation of key pro-survival signaling proteins and necrosome formation. Thus, we identified new regulatory mechanisms underlying the critical role of TAK1 in cell survival through regulation of multiple cell death checkpoints. Targeting key components of the necroptotic pathway (e.g., TRADD and CYLD) and the ubiquitin-proteasome pathway may represent novel therapeutic strategies for pathological conditions driven by necroptosis.

  14. Regulation of necrotic cell death p53, PARP1 and Cyclophilin D -overlapping pathways of regulated necrosis?

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    Ying, Yuan; Padanilam, Babu J.

    2017-01-01

    In contrast to apoptosis and autophagy, necrotic cell death was considered to be a random, passive cell death without definable mediators. However, this dogma has been challenged by recent developments suggesting that necrotic cell death can also be a regulated process. Regulated necrosis includes multiple cell death modalities such as necroptosis, parthanatos, ferroptosis, pyroptosis, and mitochondrial permeability transition pore (MPTP)-mediated necrosis. Several distinctive executive molecules, particularly residing on the mitochondrial inner and outer membrane, amalgamating to form the MPTP have been defined. The c-subunit of the F1F0ATP synthase on the inner membrane and Bax/Bak on the outer membrane are considered to be the long sought components that form the MPTP. Opening of the MPTP results in loss of mitochondrial inner membrane potential, disruption of ATP production, increased ROS production, organelle swelling, mitochondrial dysfunction and consequent necrosis. Cyclophilin D, along with adenine nucleotide translocator (ANT) and the phosphate carrier (PiC) are considered to be important regulators involved in the opening of MPTP. Increased production of ROS can further trigger other necrotic pathways mediated through molecules such as PARP1, leading to irreversible cell damage. This review examines the roles of PARP1 and cyclophilin D in necrotic cell death. The hierarchical role of p53 in regulation and integration of key components of signaling pathway to elicit MPTP-mediated necrosis and ferroptosis is explored. In the context of recent insights, the indistinct role of necroptosis signaling in tubular necrosis after ischemic kidney injury is scrutinized. We conclude by discussing the participation of p53, PARP1 and cyclophilin D and their overlapping pathways to elicit MPTP-mediated necrosis and ferroptosis in acute kidney injury. PMID:27048819

  15. Regulation of necrotic cell death: p53, PARP1 and cyclophilin D-overlapping pathways of regulated necrosis?

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    Ying, Yuan; Padanilam, Babu J

    2016-06-01

    In contrast to apoptosis and autophagy, necrotic cell death was considered to be a random, passive cell death without definable mediators. However, this dogma has been challenged by recent developments suggesting that necrotic cell death can also be a regulated process. Regulated necrosis includes multiple cell death modalities such as necroptosis, parthanatos, ferroptosis, pyroptosis, and mitochondrial permeability transition pore (MPTP)-mediated necrosis. Several distinctive executive molecules, particularly residing on the mitochondrial inner and outer membrane, amalgamating to form the MPTP have been defined. The c-subunit of the F1F0ATP synthase on the inner membrane and Bax/Bak on the outer membrane are considered to be the long sought components that form the MPTP. Opening of the MPTP results in loss of mitochondrial inner membrane potential, disruption of ATP production, increased ROS production, organelle swelling, mitochondrial dysfunction and consequent necrosis. Cyclophilin D, along with adenine nucleotide translocator and the phosphate carrier are considered to be important regulators involved in the opening of MPTP. Increased production of ROS can further trigger other necrotic pathways mediated through molecules such as PARP1, leading to irreversible cell damage. This review examines the roles of PARP1 and cyclophilin D in necrotic cell death. The hierarchical role of p53 in regulation and integration of key components of signaling pathway to elicit MPTP-mediated necrosis and ferroptosis is explored. In the context of recent insights, the indistinct role of necroptosis signaling in tubular necrosis after ischemic kidney injury is scrutinized. We conclude by discussing the participation of p53, PARP1 and cyclophilin D and their overlapping pathways to elicit MPTP-mediated necrosis and ferroptosis in acute kidney injury.

  16. Ion channels involved in cell volume regulation: effects on migration, proliferation, and programmed cell death in non adherent EAT cells and adherent ELA cells.

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    Hoffmann, Else Kay

    2011-01-01

    This mini review outlines studies of cell volume regulation in two closely related mammalian cell lines: nonadherent Ehrlich ascites tumour cells (EATC) and adherent Ehrlich Lettre ascites (ELA) cells. Focus is on the regulatory volume decrease (RVD) that occurs after cell swelling, the volume regulatory ion channels involved, and the mechanisms (cellular signalling pathways) that regulate these channels. Finally, I shall also briefly review current investigations in these two cell lines that focuses on how changes in cell volume can regulate cell functions such as cell migration, proliferation, and programmed cell death. Copyright © 2011 S. Karger AG, Basel.

  17. Remodelling of lace plant leaves: antioxidants and ROS are key regulators of programmed cell death.

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    Dauphinee, Adrian N; Fletcher, Jacob I; Denbigh, Georgia L; Lacroix, Christian R; Gunawardena, Arunika H L A N

    2017-07-01

    Antioxidants and reactive oxygen species are integral for programmed cell death signaling during perforation formation in the lace plant ( Aponogeton madagascariensis ). The lace plant is an excellent model system for studying developmentally regulated programmed cell death (PCD). During early lace plant leaf development, PCD systematically deletes cells resulting in a perforated leaf morphology that is unique in planta. A distinct feature in young lace plant leaves is an abundance of anthocyanins, which have antioxidant properties. The first sign of PCD induction is the loss of anthocyanin pigmentation in cells that are targeted for destruction, which results in a visible gradient of cell death. The cellular dynamics and time course of lace plant PCD are well documented; however, the signals involved in the pathway remain elusive. This study investigates the roles of antioxidants and ROS in developmental PCD signaling during lace plant perforation formation. The involvement of antioxidants and ROS in the pathway was determined using a variety of techniques including pharmacological whole plant experimentation, long-term live cell imaging, the 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid anti-radical activity assay, and western blot analysis. Results indicate that antioxidants and ROS are key regulators of PCD during the remodelling of lace plant leaves.

  18. Bar represses dPax2 and decapentaplegic to regulate cell fate and morphogenetic cell death in Drosophila eye.

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    Jongkyun Kang

    Full Text Available The coordinated regulation of cell fate and cell survival is crucial for normal pattern formation in developing organisms. In Drosophila compound eye development, crystalline arrays of hexagonal ommatidia are established by precise assembly of diverse cell types, including the photoreceptor cells, cone cells and interommatidial (IOM pigment cells. The molecular basis for controlling the number of cone and IOM pigment cells during ommatidial pattern formation is not well understood. Here we present evidence that BarH1 and BarH2 homeobox genes are essential for eye patterning by inhibiting excess cone cell differentiation and promoting programmed death of IOM cells. Specifically, we show that loss of Bar from the undifferentiated retinal precursor cells leads to ectopic expression of Prospero and dPax2, two transcription factors essential for cone cell specification, resulting in excess cone cell differentiation. We also show that loss of Bar causes ectopic expression of the TGFβ homolog Decapentaplegic (Dpp posterior to the morphogenetic furrow in the larval eye imaginal disc. The ectopic Dpp expression is not responsible for the formation of excess cone cells in Bar loss-of-function mutant eyes. Instead, it causes reduction in IOM cell death in the pupal stage by antagonizing the function of pro-apoptotic gene reaper. Taken together, this study suggests a novel regulatory mechanism in the control of developmental cell death in which the repression of Dpp by Bar in larval eye disc is essential for IOM cell death in pupal retina.

  19. Regulation of oogenesis in honey bee workers via programed cell death.

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    Ronai, Isobel; Barton, Deborah A; Oldroyd, Benjamin P; Vergoz, Vanina

    2015-10-01

    Reproductive division of labour characterises eusociality. Currently little is known about the mechanisms that underlie the 'sterility' of the worker caste, but queen pheromone plays a major role in regulating the reproductive state. Here we investigate oogenesis in the young adult honey bee worker ovary in the presence of queen pheromone and in its absence. When queen pheromone is absent, workers can activate their ovaries and have well-developed follicles. When queen pheromone is present, even though workers have non-activated ovaries, they continually produce oocytes which are aborted at an early stage. Therefore, irrespective of the presence of the queen, the young adult worker ovary contains oocytes. By this means young workers retain reproductive plasticity. The degeneration of the germ cells in the ovarioles of workers in the presence of queen pheromone has the morphological hallmarks of programmed cell death. Therefore the mechanistic basis of 'worker sterility' relies in part on the regulation of oogenesis via programmed cell death. Our results suggest that honey bees have co-opted a highly conserved checkpoint at mid-oogenesis to regulate the fertility of the worker caste. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Mitogen-activated protein kinase/extracellular signal-regulated kinase attenuates 3-hydroxykynurenine-induced neuronal cell death.

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    Lee, Hyun Jung; Bach, Jae-Hyung; Chae, Hee-Sun; Lee, Sang Hyung; Joo, Wan Seok; Choi, Se Hoon; Kim, Kyung Yong; Lee, Won Bok; Kim, Sung Su

    2004-02-01

    3-Hydroxykynurenine (3-HK), an endogenous tryptophan metabolite, is known to have toxic effects in brain. However, the molecular mechanism of the toxicity has not been well identified. In this study, we investigated the involvement of MAPK/extracellular signal-regulated kinase (ERK) in the 3-HK-induced neuronal cell damage. Our results showed that 3-HK induced apoptotic neuronal cell death and ERK phosphorylation occurred during cell death. Inhibition of ERK activation using PD98059 considerably increased cell death. Furthermore, cell death was preceded by mitochondrial malfunction including collapse of mitochondrial membrane potential (DeltaPsi(m)) and cytochrome c release from mitochondria to the cytosol. Interestingly, inhibition of ERK dramatically increased mitochondrial malfunction, and enhanced caspase activation, resulting in enhanced neuronal cell death. Thus, our results show that ERK plays a protective role by maintaining mitochondrial function and regulating caspase activity under conditions of cellular stress.

  1. Plasmodium falciparum exhibits markers of regulated cell death at high population density in vitro.

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    Engelbrecht, Dewaldt; Coetzer, Thérèsa Louise

    2016-12-01

    The asexual erythrocytic cycle of the protozoan parasite Plasmodium falciparum is responsible for the pathogenesis of malaria and causes the overwhelming majority of malaria deaths. Rapidly increasing parasitaemia during this 48hour cycle threatens the survival of the human host and the parasite prior to transmission of the slow-maturing sexual stages to the mosquito host. The parasite may utilise regulated cell death (RCD) to control the burden of infection on the host and thus aid its own survival and transmission. The occurrence of RCD in P. falciparum remains a controversial topic. We provide strong evidence for the occurrence of an apoptosis-like phenotype of RCD in P. falciparum under conditions of high parasite density. P. falciparum was maintained in vitro and stressed by allowing growth to an unrestricted peak parasitaemia. Cell death markers, including morphological changes, DNA fragmentation, mitochondrial polarisation and phosphatidylserine externalisation were used to characterise parasite death at the time of peak parasitaemia and 24h later. At peak parasitaemia, mitochondrial depolarisation was observed, together with phosphatidylserine externalisation in both parasitised- and neighbouring non-infected erythrocytes. DNA fragmentation coincided with a decline in parasitaemia. Fewer merozoites were observed in mature schizonts at peak parasitaemia. Growth recovery to near-peak parasitaemia was noted within two intraerythrocytic cycles. The combination and chronological order of the biochemical markers of cell death suggest the occurrence of an apoptosis-like phenotype. The identification of a RCD pathway in P. falciparum may provide novel drug targets, particularly if the pathway differs from the host machinery. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. Fluvastatin mediated breast cancer cell death: a proteomic approach to identify differentially regulated proteins in MDA-MB-231 cells.

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    Anantha Koteswararao Kanugula

    Full Text Available Statins are increasingly being recognized as anti-cancer agents against various cancers including breast cancer. To understand the molecular pathways targeted by fluvastatin and its differential sensitivity against metastatic breast cancer cells, we analyzed protein alterations in MDA-MB-231 cells treated with fluvastatin using 2-DE in combination with LC-MS/MS. Results revealed dys-regulation of 39 protein spots corresponding to 35 different proteins. To determine the relevance of altered protein profiles with breast cancer cell death, we mapped these proteins to major pathways involved in the regulation of cell-to-cell signaling and interaction, cell cycle, Rho GDI and proteasomal pathways using IPA analysis. Highly interconnected sub networks showed that vimentin and ERK1/2 proteins play a central role in controlling the expression of altered proteins. Fluvastatin treatment caused proteolysis of vimentin, a marker of epithelial to mesenchymal transition. This effect of fluvastatin was reversed in the presence of mevalonate, a downstream product of HMG-CoA and caspase-3 inhibitor. Interestingly, fluvastatin neither caused an appreciable cell death nor did modulate vimentin expression in normal mammary epithelial cells. In conclusion, fluvastatin alters levels of cytoskeletal proteins, primarily targeting vimentin through increased caspase-3- mediated proteolysis, thereby suggesting a role for vimentin in statin-induced breast cancer cell death.

  3. Programmed cell death: Superman meets Dr Death.

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    Meier, Pascal; Silke, John

    2003-12-01

    This year's Cold Spring Harbor meeting on programmed cell death (September 17-21, 2003), organised by Craig Thompson and Junying Yuan, was proof that the 'golden age' of research in this field is far from over. There was a flurry of fascinating insights into the regulation of diverse apoptotic pathways and unexpected non-apoptotic roles for some of the key apoptotic regulators and effectors. In addition to their role in cell death, components of the apoptotic molecular machinery are now known to also function in a variety of essential cellular processes, such as regulating glucose homeostasis, lipid metabolism, cell proliferation and differentiation.

  4. Integrity and regeneration of mechanotransduction machinery regulate aminoglycoside entry and sensory cell death.

    Directory of Open Access Journals (Sweden)

    Andrew A Vu

    Full Text Available Sound perception requires functional hair cell mechanotransduction (MET machinery, including the MET channels and tip-link proteins. Prior work showed that uptake of ototoxic aminoglycosides (AG into hair cells requires functional MET channels. In this study, we examined whether tip-link proteins, including Cadherin 23 (Cdh23, regulate AG entry into hair cells. Using time-lapse microscopy on cochlear explants, we found rapid uptake of gentamicin-conjugated Texas Red (GTTR into hair cells from three-day-old Cdh23(+/+ and Cdh23(v2J/+ mice, but failed to detect GTTR uptake in Cdh23(v2J/v2J hair cells. Pre-treatment of wildtype cochleae with the calcium chelator 1,2-bis(o-aminophenoxy ethane-N,N,N',N'-tetraacetic acid (BAPTA to disrupt tip-links also effectively reduced GTTR uptake into hair cells. Both Cdh23(v2J/v2J and BAPTA-treated hair cells were protected from degeneration caused by gentamicin. Six hours after BAPTA treatment, GTTR uptake remained reduced in comparison to controls; by 24 hours, drug uptake was comparable between untreated and BAPTA-treated hair cells, which again became susceptible to cell death induced by gentamicin. Together, these results provide genetic and pharmacologic evidence that tip-links are required for AG uptake and toxicity in hair cells. Because tip-links can spontaneously regenerate, their temporary breakage offers a limited time window when hair cells are protected from AG toxicity.

  5. Homotypic cell cannibalism, a cell-death process regulated by the nuclear protein 1, opposes to metastasis in pancreatic cancer

    Science.gov (United States)

    Cano, Carla E; Sandí, María José; Hamidi, Tewfik; Calvo, Ezequiel L; Turrini, Olivier; Bartholin, Laurent; Loncle, Céline; Secq, Véronique; Garcia, Stéphane; Lomberk, Gwen; Kroemer, Guido; Urrutia, Raul; Iovanna, Juan L

    2012-01-01

    Pancreatic adenocarcinoma (PDAC) is an extremely deadly disease for which all treatments available have failed to improve life expectancy significantly. This may be explained by the high metastatic potential of PDAC cells, which results from their dedifferentiation towards a mesenchymal phenotype. Some PDAC present cell-in-cell structures whose origin and significance are currently unknown. We show here that cell-in-cells form after homotypic cell cannibalism (HoCC). We found PDAC patients whose tumours display HoCC develop less metastasis than those without. In vitro, HoCC was promoted by inactivation of the nuclear protein 1 (Nupr1), and was enhanced by treatment with transforming growth factor β. HoCC ends with death of PDAC cells, consistent with a metastasis suppressor role for this phenomenon. Hence, our data indicates a protective role for HoCC in PDAC and identifies Nupr1 as a molecular regulator of this process. PMID:22821859

  6. miR-134 regulates ischemia/reperfusion injury-induced neuronal cell death by regulating CREB signaling.

    Science.gov (United States)

    Huang, Weidong; Liu, Xiaobin; Cao, Jie; Meng, Facai; Li, Min; Chen, Bo; Zhang, Jie

    2015-04-01

    microRNA-134 (miR-134) has been reported to be a brain-specific miRNA and is differently expressed in brain tissues subjected to ischemic injury. However, the underlying mechanism of miR-134 in regulating cerebral ischemic injury remains poorly understood. The current study was designed to delineate the molecular basis of miR-134 in regulating cerebral ischemic injury. Using the oxygen-glucose deprivation (OGD) model of hippocampal neuron ischemia in vitro, we found that the overexpression of miR-134 mediated by recombinant adeno-associated virus (AAV) vector infection significantly promoted neuron death induced by OGD/reoxygenation, whereas the inhibition of miR-134 provided protective effects against OGD/reoxygenation-induced cell death. Moreover, cyclic AMP (cAMP) response element-binding protein (CREB) as a putative target of miR-134 was downregulated and upregulated by miR-134 overexpression or inhibition, respectively. The direct interaction between miR-134 and the 3'-untranslated region (UTR) of CREB mRNA was further confirmed by dual-luciferase reporter assay. Overexpression of miR-134 also inhibited the expression of the downstream gene of CREB, including brain-derived neurotrophic factor (BDNF) and the anti-apoptotic gene Bcl-2, whereas the inhibition of miR-134 upregulated the expression of BDNF and Bcl-2 in neurons after OGD/reoxygenation. Notably, the knockdown of CREB by CREB siRNA apparently abrogated the protective effect of anti-miR-134 on OGD/reoxygenation-induced cell death. Taken together, our study suggests that downregulation of miR-134 alleviates ischemic injury through enhancing CREB expression and downstream genes, providing a promising and potential therapeutic target for cerebral ischemic injury.

  7. Programmed cell death and apoptosis in aging and life span regulation.

    Science.gov (United States)

    Shen, Jie; Tower, John

    2009-12-01

    Increasing evidence suggests an important role for programmed cell death (PCD) pathways in aging phenotypes across species. PCD is critical to the homeostasis of tissues maintained by cell division, for example, the blood and the lining of the gut. During aging, accumulated cellular damage and non-optimal systemic signaling can cause too little cell death (hyperproliferation and cancer), or too much cell death (tissue atrophy and ectopic cell death), thereby limiting tissue function and life span. For these reasons PCD pathways are promising targets for interventions in aging and aging-related diseases: reactivation of PCD may be beneficial in clearing cancerous and senescent cells, whereas inhibiting PCD may help prevent muscle atrophy and nervous system degeneration.

  8. Cell cycle regulation and radiation-induced cell death; Regulation du cycle cellulaire et de la mort cellulaire radio-induite

    Energy Technology Data Exchange (ETDEWEB)

    Favaudon, V. [Centre Universitaire d' Orsay, Institut Curie, Section de Recherche, Lab. Raymond-Latarjet, Unite 350 Inserm, 91 (France)

    2000-10-01

    Tight control of cell proliferation is mandatory to prevent cancer formation as well as to normal organ development and homeostasis. This occurs through checkpoints that operate in both time and space and are involved in the control of numerous pathways including DNA replication and transcription, cell cycle progression, signal transduction and differentiation. Moreover, evidence has accumulated to show that apoptosis is tightly connected with the regulation of cell cycle progression. In this paper we describe the main pathways that determine checkpoints in the cell cycle and apoptosis. It is also recalled that in solid tumors radiation-induced cell death occurs most frequently through non-apoptotic mechanisms involving oncosis, and mitotic or delayed cell death. (author)

  9. Role of a Transcriptional Regulator in Programmed Cell Death and Plant Development

    Energy Technology Data Exchange (ETDEWEB)

    Julie M. Stone

    2008-09-13

    The long-term goal of this research is to understand the role(s) and molecular mechanisms of programmed cell death (PCD) in the controlling plant growth, development and responses to biotic and abiotic stress. We developed a genetic selection scheme to identify A. thaliana FB1-resistant (fbr) mutants as a way to find genes involved in PCD (Stone et al., 2000; Stone et al., 2005; Khan and Stone, 2008). The disrupted gene in fbr6 (AtSPL14) responsible for the FB1-insensitivity and plant architecture phenotypes encodes a plant-specific SBP DNA-binding domain transcriptional regulator (Stone et al., 2005; Liang et al., 2008). This research plan is designed to fill gaps in the knowledge about the role of SPL14 in plant growth and development. The work is being guided by three objectives aimed at determining the pathways in which SPL14 functions to modulate PCD and/or plant development: (1) determine how SPL14 functions in plant development, (2) identify target genes that are directly regulated by SPL14, and (3) identify SPL14 modifications and interacting proteins. We made significant progress during the funding period. Briefly, some major accomplishments are highlighted below: (1) To identify potential AtSPL14 target genes, we identified a consensus DNA binding site for the AtSPL14 SBP DNA-binding domain using systematic evolution of ligands by exponential selection (SELEX) and site-directed mutagenesis (Liang et al., 2008). This consensus binding site was used to analyze Affymetrix microarray gene expression data obtained from wild-type and fbr6 mutant plants to find possible AtSPL14-regulated genes. These candidate AtSPL14-regulated genes are providing new information on the molecular mechanisms linking plant PCD and plant development through modulation of the 26S proteasome. (2) Transgenic plants expressing epitope-tagged versions of AtSPL14 are being used to confirm the AtSPL14 targets (by ChIP-PCR) and further dissect the molecular interactions (Nazarenus, Liang

  10. In Vitro Effects of Bromoalkyl Phenytoin Derivatives on Regulated Death, Cell Cycle and Ultrastructure of Leukemia Cells.

    Science.gov (United States)

    Śladowska, Katarzyna; Opydo-Chanek, Małgorzata; Król, Teodora; Trybus, Wojciech; Trybus, Ewa; Kopacz-Bednarska, Anna; Handzlik, Jadwiga; Kieć-Kononowicz, Katarzyna; Mazur, Lidia

    2017-11-01

    To search for new antileukemic agents, the chemical structure of phenytoin was modified. A possible cytotoxic activity of three bromoalkyl phenytoin analogs, methyl 2-(1-(3-bromopropyl)-2,4-dioxo-5,5-diphenylimidazolidin-3-yl) propanoate (PH2), 1-(3-bromopropyl)-3-methyl-5,5-diphenylimidazolidine-2,4-dione (PH3) and 1-(4-bromobutyl)-3-methyl-5,5-diphenylimidazolidine-2,4-dione (PH4) on regulated cell death, the cell cycle and cell ultrastructure was assessed. The experiments were performed in vitro on HL-60 and U937 cells, using flow cytometry and electron microscopy methods. Application of PH2, PH3, and PH4 resulted in cell surface exposure of phosphatidylserine and plasma membrane impairment, caspase-8, -9, and -3/7 activation, dissipation of mitochondrial membrane potential, DNA breakage, cell-cycle disturbance and cell ultrastructural changes. In general, PH3 appeared to be the most active against the leukemia cells, and all bromoalkyl hydantoins, PH2-PH4, were more active in HL-60 cells than in U937 cells. The antileukemic activity of the bromoalkyl phenytoin analogs depended on the combination of N-hydantoin substituents and the human cell line used. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  11. C/EBP-beta regulates endoplasmic reticulum stress-triggered cell death in mouse and human models.

    Directory of Open Access Journals (Sweden)

    Ofir Meir

    2010-03-01

    Full Text Available Endoplasmic reticulum (ER stress elicits the unfolded protein response (UPR, initially aimed at coping with the stress, but triggering cell death upon further stress. ER stress induces the C/EBP-beta variant Liver-enriched Activating Protein (LAP, followed by the dominant-negative variant, Liver Inhibitory Protein (LIP. However, the distinct role of LAP and LIP in ER stress is unknown. We found that the kinetics of the ER stress-induced expression of LIP overlapped with that of the cell death in mouse B16 melanoma cells. Furthermore, inducible over-expression of LIP augmented ER stress-triggered cell death whereas over-expression of LAP attenuated cell death. Similar results were obtained in human 293T cells. Limited vasculature in tumors triggers hypoxia, nutrient shortage and accumulation of toxic metabolites, all of which eliciting continuous ER stress. We found that LAP promoted and LIP inhibited B16 melanoma tumor progression without affecting angiogenesis or accelerating the cell cycle. Rather, LAP attenuated, whereas LIP augmented tumor ER stress. We therefore suggest that C/EBP-beta regulates the transition from the protective to the death-promoting phase of the UPR. We further suggest that the over-expression of LAP observed in many solid tumors promotes tumor progression by attenuating ER stress-triggered tumor cell death [corrected].

  12. Cloning and expression of the programmed cell death regulator Bad in the rat brain.

    Science.gov (United States)

    D'Agata, V; Magro, G; Travali, S; Musco, S; Cavallaro, S

    1998-02-27

    The Bcl-2 family of proteins consists of both antagonists (e.g. Bcl-2) and agonists (e.g. Bax) that regulate apoptosis and compete through dimerization. In the present study we cloned the cDNA encoding the rat brain BAD, a distant member of the Bcl-2 family that was shown to promote cell death. The cloned cDNA encoded a protein of 205 amino acids, containing three putative Bcl-2 homology domains (BH1, BH2 and BH3) and no C-terminal signal-anchor sequence. The predicted amino acid sequence was identical to the Bad-cDNA recently cloned from the rat ovary with the exception of a stretch of six amino acids, thus indicating the existence of two Bad alternative splice variants or a sequence artifact in the rat ovary Bad-cDNA. Immunohistochemical analysis in the rat brain revealed the exclusive expression of Bad in the epithelial cells of the choroid plexus, a result which is consistent with a very specialized function of Bad in the brain.

  13. Sesaminol glucosides protect β-amyloid induced apoptotic cell death by regulating redox system in SK-N-SH cells.

    Science.gov (United States)

    Um, Min Young; Ahn, Ji Yun; Kim, Mi Kyung; Ha, Tae Youl

    2012-04-01

    We have investigated the neuroprotective effect of sesaminol glucosides (SG) in SK-N-SH cells. SG prevented apoptotic cell death induced by Aβ₂₅₋₃₅. In parallel, SK-N-SH cells exposed to Aβ₂₅₋₃₅ underwent oxidative stress as shown by the elevated level of intracellular ROS, lipid peroxidation, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation, which were effectively suppressed by SG treatment. Furthermore, SG reversed the activities of catalase and glutathione peroxidase, and restored intracellular GSH levels in Aβ₂₅₋₃₅ challenged SK-N-SH cells. In addition, SG inhibited not only Aβ₂₅₋₃₅-induced apoptotic features including cleavage of poly(ADP-ribose) polymerase, activation of caspase-3, and activation of caspase-9, but also elevated Bax/Bcl-2 ratio in SK-N-SH cells treated with Aβ₂₅₋₃₅. It was also observed that Aβ₂₅₋₃₅ stimulated the phosphorylation of mitogen-activated protein kinases (MAPKs), including extracellular protein regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAP kinase. SG inhibited phosphorylation of the JNK, ERK and p38 MAP kinase. These results suggest that SG has a protective effect against Aβ₂₅₋₃₅-induced neuronal apoptosis, possibly through scavenging oxidative stress and regulating MAPKs signaling pathways.

  14. Role of Aif1 in regulation of cell death under environmental stress in Candida albicans.

    Science.gov (United States)

    Ma, Feiyang; Zhang, Yueqi; Wang, Yuzhou; Wan, Yajuan; Miao, Yunheng; Ma, Tianyu; Yu, Qilin; Li, Mingchun

    2016-09-01

    Apoptosis-inducing factor (AIF) is a conserved flavoprotein localized in the mitochondria, inducing apoptosis after translocation into the nucleus. However, its role in the important fungal pathogen, Candida albicans, remains to be investigated. In this study, we find that the C. albicans AIF protein Aif1, similar to its homologues in other organisms, is localized at the mitochondria and translocated into the nucleus under apoptosis-inducing conditions. Moreover, deletion of AIF1 causes attenuated apoptosis in this pathogen under apoptosis-inducing conditions, such as the treatment of 2 mm H2 O2 , 10 mm acetic acid or 0.08 mg/l caspofungin, and its overexpression enhances this process. Interestingly, treatment with high levels of these agents leads to reversed sensitivity of aif1Δ/Δ and the overexpression strain AIF1ov. In addition, the virulence of C. albicans is not affected by deletion or overexpression of AIF1. Hence, C. albicans Aif1, as a mitochondria-localized protein, plays a dual role in the regulation of cell death under different concentrations of the stress-caused agents. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Chloroplasts activity and PAP-signaling regulate programmed cell death in Arabidopsis

    KAUST Repository

    Bruggeman, Quentin

    2016-01-09

    Programmed cell death (PCD) is a crucial process both for plant development and responses to biotic and abiotic stress. There is accumulating evidence that chloroplasts may play a central role during plant PCD as for mitochondria in animal cells, but it is still unclear whether they participate in PCD onset, execution, or both. To tackle this question, we have analyzed the contribution of chloroplast function to the cell death phenotype of the myoinositol phosphate synthase1 (mips1) mutant that forms spontaneous lesions in a light-dependent manner. We show that photosynthetically active chloroplasts are required for PCD to occur in mips1, but this process is independent of the redox state of the chloroplast. Systematic genetic analyses with retrograde signaling mutants reveal that 3’-phosphoadenosine 5’-phosphate, a chloroplast retrograde signal that modulates nuclear gene expression in response to stress, can inhibit cell death and compromises plant innate immunity via inhibition of the RNA-processing 5’-3’ exoribonucleases. Our results provide evidence for the role of chloroplast-derived signal and RNA metabolism in the control of cell death and biotic stress response. © 2016 American Society of Plant Biologists. All Rights Reserved.

  16. Glutathione Efflux and Cell Death

    Science.gov (United States)

    2012-01-01

    Abstract Significance: Glutathione (GSH) depletion is a central signaling event that regulates the activation of cell death pathways. GSH depletion is often taken as a marker of oxidative stress and thus, as a consequence of its antioxidant properties scavenging reactive species of both oxygen and nitrogen (ROS/RNS). Recent Advances: There is increasing evidence demonstrating that GSH loss is an active phenomenon regulating the redox signaling events modulating cell death activation and progression. Critical Issues: In this work, we review the role of GSH depletion by its efflux, as an important event regulating alterations in the cellular redox balance during cell death independent from oxidative stress and ROS/RNS formation. We discuss the mechanisms involved in GSH efflux during cell death progression and the redox signaling events by which GSH depletion regulates the activation of the cell death machinery. Future Directions: The evidence summarized here clearly places GSH transport as a central mechanism mediating redox signaling during cell death progression. Future studies should be directed toward identifying the molecular identity of GSH transporters mediating GSH extrusion during cell death, and addressing the lack of sensitive approaches to quantify GSH efflux. Antioxid. Redox Signal. 17, 1694–1713. PMID:22656858

  17. Up-regulation of K{sub ir}2.1 by ER stress facilitates cell death of brain capillary endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Kito, Hiroaki [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Yamazaki, Daiju [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Department of Biological Chemistry, Kyoto University, Graduate School of Pharmaceutical Sciences, Kyoto (Japan); Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Ohya, Susumu; Yamamura, Hisao [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Asai, Kiyofumi [Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Imaizumi, Yuji, E-mail: yimaizum@phar.nagoya-cu.ac.jp [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan)

    2011-07-29

    Highlights: {yields} We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. {yields} The ER stress facilitated the expression of inward rectifier K{sup +} channel (K{sub ir}2.1) and induced sustained membrane hyperpolarization. {yields} The membrane hyperpolarization induced sustained Ca{sup 2+} entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. {yields} The K{sub ir}2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K{sup +} channel (K{sub ir}2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K{sub ir} channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca{sup 2+} concentration due to Ca{sup 2+} influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K{sub ir}2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

  18. CHIP has a protective role against oxidative stress-induced cell death through specific regulation of Endonuclease G

    Science.gov (United States)

    Lee, J S; Seo, T W; Yi, J H; Shin, K S; Yoo, S J

    2013-01-01

    Oxidative stress is implicated in carcinogenesis, aging, and neurodegenerative diseases. The E3 ligase C terminus of Hsc-70 interacting protein (CHIP) has a protective role against various stresses by targeting damaged proteins for proteasomal degradation, and thus maintains protein quality control. However, the detailed mechanism by which CHIP protects cells from oxidative stress has not been demonstrated. Here, we show that depletion of CHIP led to elevated Endonuclease G (EndoG) levels and enhanced cell death upon oxidative stress. In contrast, CHIP overexpression reduced EndoG levels, and resulted in reduced or no oxidative stress-induced cell death in cancer cells and primary rat cortical neurons. Under normal conditions Hsp70 mediated the interaction between EndoG and CHIP, downregulating EndoG levels in a Hsp70/proteasome-dependent manner. However, under oxidative stress Hsp70 no longer interacted with EndoG, and the stabilized EndoG translocated to the nucleus and degraded chromosomal DNA. Our data suggest that regulation of the level of EndoG by CHIP in normal conditions may determine the sensitivity to cell death upon oxidative stress. Indeed, injection of H2O2 into the rat brain markedly increased cell death in aged mice compared with young mice, which correlated with elevated levels of EndoG and concurrent downregulation of CHIP in aged mice. Taken together, our findings demonstrate a novel protective mechanism of CHIP against oxidative stress through regulation of EndoG, and provide an opportunity to modulate oxidative stress-induced cell death in cancer and aging. PMID:23764847

  19. Cancer: brain-regulated biphasic stress response induces cell growth or cell death to adapt to psychological stressors.

    Science.gov (United States)

    Thomas, Charles; Bhatia, Shruti

    2014-01-01

    According to Indian Vedic philosophy, a human being contains 3 major bodies: (1) the matter body--brain, organs, and senses; (2) the mental body--mind, individual consciousness, intellect, and ego; and (3) the soul or causal body--universal consciousness. The third, which is located in the heart according to all spiritual traditions and recent scientific literature, can be seen as the information body that contains all memories. The mental body, which can interface with the matter and information bodies, can be seen as a field of immaterial energy that can carry, regulate, and strengthen all information (eg, thoughts or emotions) both positively and negatively. This body of information may store ancestral and/or autobiographical memories: unconscious memories from inner traumas--inner information (Ii) or samskaras in Vedic philosophy--and conscious memories from outer traumas--outer information (Io). These conscious and unconscious memories can be seen as potential psychological stressors. Resonance between Ii and Io may induce active conflicts if resistance occurs in the mental body; this conflict may cause specific metabolic activity in the brain and a stress response in the physical body, which permits adjustment to psychological stressors. The brainregulated stress response may be biphasic: cell death or growth induced by adrenergic molecular pathways during the conflict's unresolved phase and reversion to cell growth or death induced by cholinergic molecular pathways during the conflict's resolved phase. Case studies and data mining from PubMed suggest that this concept complies with the principles of holistic medicine and the scientific literature supporting its benefits. We suggest that the evolution of cancer can be seen as a biphasic stress response regulated by the brain to adapt to psychological stressors, which produce imbalance among the physical, mental, and information bodies.

  20. Necrosis, a regulated mechanism of cell death La necrosis, un mecanismo regulado de muerte celular

    Directory of Open Access Journals (Sweden)

    Mauricio Rojas López

    2010-05-01

    Full Text Available

    Three types of cellular death have been defined by morphological and biochemical criteria: apoptosis, necrosis and autophagy. Apoptosis is a regulated cell death, mainly mediated by caspases; autophagy induces degradation of intracellular damaged organelles through the formation of vesicles that fuse with hydrolytic vacuoles.

     

    Necrosis has been traditionally defined by the rupture the cytoplasmic membrane with subsequent release of intracellular material, triggering localized inflammatory Intrinsic cellular activities and the events preceding cellular collapse are critical to determine the type of tissue damage.

     

    The fact that all three types of cellular death can coexist in any organ and tissue with different availabilities of ATP, suggests that necrosis can be conceived as an active event and that to some extent it may be regulated. Alterations in the structure of proteins and in the

  1. The Fas/CD95 receptor regulates the death of autoreactive B cells and the selection of antigen-specific B cells

    Directory of Open Access Journals (Sweden)

    Anne-Odile eHUEBER

    2012-07-01

    Full Text Available Cell death receptors have crucial roles in the regulation of immune responses. Here we review recent in vivo data confirming that the Fas death receptor (TNFSR6 on B cells is important for the regulation of autoimmunity since the impairment of only Fas function on B cells results in uncontrolled autoantibody production and autoimmunity. Fas plays a role in the elimination of the non-specific and auto-reactive B cells in germinal center, while during the selection of antigen specific B cells different escape signals ensure the resistance to Fas-mediated apoptosis. Antigen specific survival such as BCR or MHCII signal or coreceptors (CD19 cooperating with BCR inhibits the formation of death inducing signaling complex. Antigen-specific survival can be reinforced by antigen-independent signals of IL4 or CD40 overproducing the anti-apoptotic members of the Bcl-2 family proteins.

  2. Antitumor effects of a sirtuin inhibitor, tenovin-6, against gastric cancer cells via death receptor 5 up-regulation.

    Directory of Open Access Journals (Sweden)

    Sachiko Hirai

    Full Text Available Up-regulated sirtuin 1 (SIRT1, an NAD+-dependent class III histone deacetylase, deacetylates p53 and inhibits its transcriptional activity, leading to cell survival. SIRT1 overexpression has been reported to predict poor survival in some malignancies, including gastric cancer. However, the antitumor effect of SIRT1 inhibition remains elusive in gastric cancer. Here, we investigated the antitumor mechanisms of a sirtuin inhibitor, tenovin-6, in seven human gastric cancer cell lines (four cell lines with wild-type TP53, two with mutant-type TP53, and one with null TP53. Interestingly, tenovin-6 induced apoptosis in all cell lines, not only those with wild-type TP53, but also mutant-type and null versions, accompanied by up-regulation of death receptor 5 (DR5. In the KatoIII cell line (TP53-null, DR5 silencing markedly attenuated tenovin-6-induced apoptosis, suggesting that the pivotal mechanism behind its antitumor effects is based on activation of the death receptor signal pathway. Although endoplasmic reticulum stress caused by sirtuin inhibitors was reported to induce DR5 up-regulation in other cancer cell lines, we could not find marked activation of its related molecules, such as ATF6, PERK, and CHOP, in gastric cancer cells treated with tenovin-6. Tenovin-6 in combination with docetaxel or SN-38 exerted a slight to moderate synergistic cytotoxicity against gastric cancer cells. In conclusion, tenovin-6 has potent antitumor activity against human gastric cancer cells via DR5 up-regulation. Our results should be helpful for the future clinical development of sirtuin inhibitors.

  3. APAF1 is a key transcriptional target for p53 in the regulation of neuronal cell death

    DEFF Research Database (Denmark)

    Fortin, A; Cregan, S P; MacLaurin, J G

    2001-01-01

    cell death, Apaf1 protein levels were increased. We addressed whether p53 directly regulates Apaf1 transcription via the two p53 consensus binding sites in the Apaf1 promoter. Electrophoretic mobility shift assays demonstrated p53-DNA binding activity at both p53 consensus binding sequences in extracts...... of this process have not been identified. In the present study, we demonstrate that p53 directly upregulates Apaf1 transcription as a critical step in the induction of neuronal cell death. Using DNA microarray analysis of total RNA isolated from neurons undergoing p53-induced apoptosis a 5-6-fold upregulation...... of Apaf1 mRNA was detected. Induction of neuronal cell death by camptothecin, a DNA-damaging agent that functions through a p53-dependent mechanism, resulted in increased Apaf1 mRNA in p53-positive, but not p53-deficient neurons. In both in vitro and in vivo neuronal cell death processes of p53-induced...

  4. High glucose-induced apoptosis in human coronary artery endothelial cells involves up-regulation of death receptors

    Directory of Open Access Journals (Sweden)

    Yamamoto Seiji

    2011-08-01

    Full Text Available Abstract Background High glucose can induce apoptosis in vascular endothelial cells, which may contribute to the development of vascular complications in diabetes. We evaluated the role of the death receptor pathway of apoptotic signaling in high glucose-induced apoptosis in human coronary artery endothelial cells (HCAECs. Methods HCAECs were treated with media containing 5.6, 11.1, and 16.7 mM of glucose for 24 h in the presence or absence of tumor necrosis factor (TNF-α. For detection of apoptosis, DNA fragmentation assay was used. HCAEC expression of death receptors were analyzed by the PCR and flow cytometry methods. Also, using immunohistochemical techniques, coronary expression of death receptors was assessed in streptozotocin-nicotinamide-induced type 2 diabetic mice. Results Exposure of HCAECs to high glucose resulted in a significant increase in TNF-R1 and Fas expression, compared with normal glucose. High glucose increased TNF-α production by HCAECs and exogenous TNF-α up-regulated TNF-R1 and Fas expression in HCAECs. High glucose-induced up-regulation of TNF-R1 and Fas expression was undetectable in the presence of TNF-α. Treatment with TNF-R1 neutralizing peptides significantly inhibited high glucose-induced endothelial cell apoptosis. Type 2 diabetic mice displayed appreciable expression of TNF-R1 and Fas in coronary vessels. Conclusions In association with increased TNF-α levels, the death receptors, TNF-R1 and Fas, are up-regulated in HCAECs under high glucose conditions, which could in turn play a role in high glucose-induced endothelial cell apoptosis.

  5. α-Hispanolol sensitizes hepatocellular carcinoma cells to TRAIL-induced apoptosis via death receptor up-regulation

    Energy Technology Data Exchange (ETDEWEB)

    Mota, Alba, E-mail: amota@iib.uam.es [Unidad de Terapias Farmacológicas, Área de Genética Humana, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III, Madrid (Spain); Jiménez-Garcia, Lidia, E-mail: ljimenez@isciii.es [Unidad de Terapias Farmacológicas, Área de Genética Humana, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III, Madrid (Spain); Herránz, Sandra, E-mail: sherranz@isciii.es [Unidad de Terapias Farmacológicas, Área de Genética Humana, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III, Madrid (Spain); Heras, Beatriz de las, E-mail: lasheras@ucm.es [Departamento de Farmacología, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), Madrid (Spain); Hortelano, Sonsoles, E-mail: shortelano@isciii.es [Unidad de Terapias Farmacológicas, Área de Genética Humana, Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III, Madrid (Spain)

    2015-08-01

    Hispanolone derivatives have been previously described as anti-inflammatory and antitumoral agents. However, their effects on overcoming Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resistance remain to be elucidated. In this study, we analyzed the cytotoxic effects of the synthetic hispanolone derivative α-hispanolol (α-H) in several tumor cell lines, and we evaluated the induction of apoptosis, as well as the TRAIL-sensitizing potential of α-H in the hepatocellular carcinoma cell line HepG2. Our data show that α-H decreased cell viability in a dose-dependent manner in HeLa, MDA-MB231, U87 and HepG2 cell lines, with a more prominent effect in HepG2 cells. Interestingly, α-H had no effect on non-tumoral cells. α-H induced activation of caspase-8 and caspase-9 and also increased levels of the proapoptotic protein Bax, decreasing antiapoptotic proteins (Bcl-2, X-IAP and IAP-1) in HepG2 cells. Specific inhibition of caspase-8 abrogated the cascade of caspase activation, suggesting that the extrinsic pathway has a critical role in the apoptotic events induced by α-H. Furthermore, combined treatment of α-H with TRAIL enhanced apoptosis in HepG2 cells, activating caspase-8 and caspase-9. This correlated with up-regulation of both the TRAIL death receptor DR4 and DR5. DR4 or DR5 neutralizing antibodies abolished the effect of α-H on TRAIL-induced apoptosis, suggesting that sensitization was mediated through the death receptor pathway. Our results demonstrate that α-H induced apoptosis in the human hepatocellular carcinoma cell line HepG2 through activation of caspases and induction of the death receptor pathway. In addition, we describe a novel function of α-H as a sensitizer on TRAIL-induced apoptotic cell death in HepG2 cells. - Highlights: • α-Hispanolol induced apoptosis in the human hepatocellular carcinoma cell line HepG2. • α-Hispanolol induced activation of caspases and the death receptor pathway. • α-Hispanolol enhanced

  6. TAK1 control of cell death

    OpenAIRE

    Mihaly, S R; Ninomiya-Tsuji, J; Morioka, S

    2014-01-01

    Programmed cell death, a physiologic process for removing cells, is critically important in normal development and for elimination of damaged cells. Conversely, unattended cell death contributes to a variety of human disease pathogenesis. Thus, precise understanding of molecular mechanisms underlying control of cell death is important and relevant to public health. Recent studies emphasize that transforming growth factor-β-activated kinase 1 (TAK1) is a central regulator of cell death and is ...

  7. Drosophila caspases involved in developmentally regulated programmed cell death of peptidergic neurons during early metamorphosis.

    Science.gov (United States)

    Lee, Gyunghee; Wang, Zixing; Sehgal, Ritika; Chen, Chun-Hong; Kikuno, Keiko; Hay, Bruce; Park, Jae H

    2011-01-01

    A great number of obsolete larval neurons in the Drosophila central nervous system are eliminated by developmentally programmed cell death (PCD) during early metamorphosis. To elucidate the mechanisms of neuronal PCD occurring during this period, we undertook genetic dissection of seven currently known Drosophila caspases in the PCD of a group of interneurons (vCrz) that produce corazonin (Crz) neuropeptide in the ventral nerve cord. The molecular death program in the vCrz neurons initiates within 1 hour after pupariation, as demonstrated by the cytological signs of cell death and caspase activation. PCD was significantly suppressed in dronc-null mutants, but not in null mutants of either dredd or strica. A double mutation lacking both dronc and strica impaired PCD phenotype more severely than did a dronc mutation alone, but comparably to a triple dredd/strica/dronc mutation, indicating that dronc is a main initiator caspase, while strica plays a minor role that overlaps with dronc's. As for effector caspases, vCrz PCD requires both ice and dcp-1 functions, as they work cooperatively for a timely removal of the vCrz neurons. Interestingly, the activation of the Ice and Dcp-1 is not solely dependent on Dronc and Strica, implying an alternative pathway to activate the effectors. Two remaining effector caspase genes, decay and damm, found no apparent functions in the neuronal PCD, at least during early metamorphosis. Overall, our work revealed that vCrz PCD utilizes dronc, strica, dcp-1, and ice wherein the activation of Ice and Dcp-1 requires a novel pathway in addition to the initiator caspases.

  8. Multiple Domain Associations within the Arabidopsis Immune Receptor RPP1 Regulate the Activation of Programmed Cell Death.

    Directory of Open Access Journals (Sweden)

    Karl J Schreiber

    2016-07-01

    Full Text Available Upon recognition of pathogen virulence effectors, plant nucleotide-binding leucine-rich repeat (NLR proteins induce defense responses including localized host cell death. In an effort to understand the molecular mechanisms leading to this response, we examined the Arabidopsis thaliana NLR protein RECOGNITION OF PERONOSPORA PARASITICA1 (RPP1, which recognizes the Hyaloperonospora arabidopsidis effector ARABIDOPSIS THALIANA RECOGNIZED1 (ATR1. Expression of the N-terminus of RPP1, including the Toll/interleukin-1 receptor (TIR domain ("N-TIR", elicited an effector-independent cell death response, and we used allelic variation in TIR domain sequences to define the key residues that contribute to this phenotype. Further biochemical characterization indicated that cell death induction was correlated with N-TIR domain self-association. In addition, we demonstrated that the nucleotide-binding (NB-ARC1 region of RPP1 self-associates and plays a critical role in cell death activation, likely by facilitating TIR:TIR interactions. Structural homology modeling of the NB subdomain allowed us to identify a putative oligomerization interface that was shown to influence NB-ARC1 self-association. Significantly, full-length RPP1 exhibited effector-dependent oligomerization and, although mutations at the NB-ARC1 oligomerization interface eliminated cell death induction, RPP1 self-association was unaffected, suggesting that additional regions contribute to oligomerization. Indeed, the leucine-rich repeat domain of RPP1 also self-associates, indicating that multiple interaction interfaces exist within activated RPP1 oligomers. Finally, we observed numerous intramolecular interactions that likely function to negatively regulate RPP1, and present a model describing the transition to an active NLR protein.

  9. Programmed cell death

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The purpose of this conference to provide a multidisciplinary forum for exchange of state-of-the-art information on the role programmed cell death plays in normal development and homeostasis of many organisms. This volume contains abstracts of papers in the following areas: invertebrate development; immunology/neurology; bcl-2 family; biochemistry; programmed cell death in viruses; oncogenesis; vertebrate development; and diseases.

  10. Intracellular cholesterol level regulates sensitivity of glioblastoma cells against temozolomide-induced cell death by modulation of caspase-8 activation via death receptor 5-accumulation and activation in the plasma membrane lipid raft.

    Science.gov (United States)

    Yamamoto, Yutaro; Tomiyama, Arata; Sasaki, Nobuyoshi; Yamaguchi, Hideki; Shirakihara, Takuya; Nakashima, Katsuhiko; Kumagai, Kosuke; Takeuchi, Satoru; Toyooka, Terushige; Otani, Naoki; Wada, Kojiro; Narita, Yoshitaka; Ichimura, Koichi; Sakai, Ryuichi; Namba, Hiroki; Mori, Kentaro

    2018-01-01

    Development of resistance against temozolomide (TMZ) in glioblastoma (GBM) after continuous treatment with TMZ is one of the critical problems in clinical GBM therapy. Intracellular cholesterol regulates cancer cell biology, but whether intracellular cholesterol is involved in TMZ resistance of GBM cells remains unclear. The involvement of intracellular cholesterol in acquired resistance against TMZ in GBM cells was investigated. Intracellular cholesterol levels were measured in human U251 MG cells with acquired TMZ resistance (U251-R cells) and TMZ-sensitive control U251 MG cells (U251-Con cells), and found that the intracellular cholesterol level was significantly lower in U251-R cells than in U251-Con cells. In addition, treatment by intracellular cholesterol remover, methyl-beta cyclodextrin (MβCD), or intracellular cholesterol inducer, soluble cholesterol (Chol), regulated TMZ-induced U251-Con cell death in line with changes in intracellular cholesterol level. Involvement of death receptor 5 (DR5), a death receptor localized in the plasma membrane, was evaluated. TMZ without or with MβCD and/or Chol caused accumulation of DR5 into the plasma membrane lipid raft and formed a complex with caspase-8, an extrinsic caspase cascade inducer, reflected in the induction of cell death. In addition, treatment with caspase-8 inhibitor or knockdown of DR5 dramatically suppressed U251-Con cell death induced by combination treatment with TMZ, MβCD, and Chol. Combined treatment of Chol with TMZ reversed the TMZ resistance of U251-R cells and another GBM cell model with acquired TMZ resistance, whereas clinical antihypercholesterolemia agents at physiological concentrations suppressed TMZ-induced cell death of U251-Con cells. These findings suggest that intracellular cholesterol level affects TMZ treatment of GBM mediated via a DR5-caspase-8 mechanism. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. dLKR/SDH regulates hormone-mediated histone arginine methylation and transcription of cell death genes.

    Science.gov (United States)

    Cakouros, Dimitrios; Mills, Kathryn; Denton, Donna; Paterson, Alicia; Daish, Tasman; Kumar, Sharad

    2008-08-11

    The sequential modifications of histones form the basis of the histone code that translates into either gene activation or repression. Nuclear receptors recruit a cohort of histone-modifying enzymes in response to ligand binding and regulate proliferation, differentiation, and cell death. In Drosophila melanogaster, the steroid hormone ecdysone binds its heterodimeric receptor ecdysone receptor/ultraspiracle to spatiotemporally regulate the transcription of several genes. In this study, we identify a novel cofactor, Drosophila lysine ketoglutarate reductase (dLKR)/saccharopine dehydrogenase (SDH), that is involved in ecdysone-mediated transcription. dLKR/SDH binds histones H3 and H4 and suppresses ecdysone-mediated transcription of cell death genes by inhibiting histone H3R17me2 mediated by the Drosophila arginine methyl transferase CARMER. Our data suggest that the dynamic recruitment of dLKR/SDH to ecdysone-regulated gene promoters controls the timing of hormone-induced gene expression. In the absence of dLKR/SDH, histone methylation occurs prematurely, resulting in enhanced gene activation. Consistent with these observations, the loss of dLKR/SDH in Drosophila enhances hormone-regulated gene expression, affecting the developmental timing of gene activation.

  12. NR2B-NMDA receptor mediated modulation of the tyrosine phosphatase STEP regulates glutamate induced neuronal cell death

    Science.gov (United States)

    Poddar, Ranjana; Deb, Ishani; Mukherjee, Saibal; Paul, Surojit

    2011-01-01

    The present study examines the role of a neuron-specific tyrosine phosphatase (STEP) in excitotoxic cell death. Our findings demonstrate that p38 MAPK, a stress-activated kinase that is known to play a role in the etiology of excitotoxic cell death is a substrate of STEP. Glutamate-mediated NMDA receptor stimulation leads to rapid but transient activation of p38 MAPK, which is primarily dependent on NR2A-NMDA receptor activation. Conversely, activation of NR2B-NMDA receptors leads to dephosphorylation and subsequent activation of STEP, which in turn leads to inactivation of p38 MAPK. Thus during transient NMDA receptor stimulation, increases in STEP activity appears to limit the duration of activation of p38 MAPK and improves neuronal survival. However, if NR2B-NMDA receptor stimulation is sustained, protective effects of STEP activation are lost, as these stimuli cause significant degradation of active STEP, leading to secondary activation of p38 MAP kinase. Consistent with this observation, a cell transducible TAT-STEP peptide that constitutively binds to p38 MAPK attenuated neuronal cell death caused by sustained NMDA receptor stimulation. The findings imply that the activation and levels of STEP are dependent on the duration and magnitude of NR2B-NMDA receptor stimulation and STEP serves as a modulator of NMDA receptor dependent neuronal injury, through its regulation of p38 MAPK. PMID:21029094

  13. Glutathione in Cancer Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Angel L. [Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 17 Av. Blasco Ibanez, 46010 Valencia (Spain); Mena, Salvador [Green Molecular SL, Pol. Ind. La Coma-Parc Cientific, 46190 Paterna, Valencia (Spain); Estrela, Jose M., E-mail: jose.m.estrela@uv.es [Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 17 Av. Blasco Ibanez, 46010 Valencia (Spain)

    2011-03-11

    Glutathione (L-γ-glutamyl-L-cysteinyl-glycine; GSH) in cancer cells is particularly relevant in the regulation of carcinogenic mechanisms; sensitivity against cytotoxic drugs, ionizing radiations, and some cytokines; DNA synthesis; and cell proliferation and death. The intracellular thiol redox state (controlled by GSH) is one of the endogenous effectors involved in regulating the mitochondrial permeability transition pore complex and, in consequence, thiol oxidation can be a causal factor in the mitochondrion-based mechanism that leads to cell death. Nevertheless GSH depletion is a common feature not only of apoptosis but also of other types of cell death. Indeed rates of GSH synthesis and fluxes regulate its levels in cellular compartments, and potentially influence switches among different mechanisms of death. How changes in gene expression, post-translational modifications of proteins, and signaling cascades are implicated will be discussed. Furthermore, this review will finally analyze whether GSH depletion may facilitate cancer cell death under in vivo conditions, and how this can be applied to cancer therapy.

  14. Caspase-10 Negatively Regulates Caspase-8-Mediated Cell Death, Switching the Response to CD95L in Favor of NF-κB Activation and Cell Survival

    Directory of Open Access Journals (Sweden)

    Sebastian Horn

    2017-04-01

    Full Text Available Formation of the death-inducing signaling complex (DISC initiates extrinsic apoptosis. Caspase-8 and its regulator cFLIP control death signaling by binding to death-receptor-bound FADD. By elucidating the function of the caspase-8 homolog, caspase-10, we discover that caspase-10 negatively regulates caspase-8-mediated cell death. Significantly, we reveal that caspase-10 reduces DISC association and activation of caspase-8. Furthermore, we extend our co-operative/hierarchical binding model of caspase-8/cFLIP and show that caspase-10 does not compete with caspase-8 for binding to FADD. Utilizing caspase-8-knockout cells, we demonstrate that caspase-8 is required upstream of both cFLIP and caspase-10 and that DISC formation critically depends on the scaffold function of caspase-8. We establish that caspase-10 rewires DISC signaling to NF-κB activation/cell survival and demonstrate that the catalytic activity of caspase-10, and caspase-8, is redundant in gene induction. Thus, our data are consistent with a model in which both caspase-10 and cFLIP coordinately regulate CD95L-mediated signaling for death or survival.

  15. Precise temporal regulation of roughest is required for correct salivary gland autophagic cell death in Drosophila.

    Science.gov (United States)

    Simon, Claudio R; Moda, Livia M R; Octacilio-Silva, Shirlei; Anhezini, Lucas; Machado-Gitai, Luciana C H; Ramos, Ricardo Guelerman P

    2009-07-01

    The Drosophila roughest (rst) locus encodes an immunoglobulin superfamily transmembrane glycoprotein implicated in a variety of embryonic and postembryonic developmental processes. Here we demonstrate a previously unnoticed role for this gene in the autophagic elimination of larval salivary glands during early pupal stages by showing that overexpression of the Rst protein ectodomain in early pupa leads to persistence of salivary glands up to at least 12 hours after head eversion, although with variable penetrance. The same phenotype is observed in individuals carrying the dominant regulatory allele rst(D), but not in loss of function alleles. Analysis of persistent glands at the ultrastructural level showed that programmed cell death starts at the right time but is arrested at an early stage of the process. Finally we describe the expression pattern and intracellular distribution of Rst in wild type and rst(D) mutants, showing that its downregulation in salivary glands at the beginning of pupal stage is an important factor in the correct implementation of the autophagic program of this tissue in space and time. 2009 Wiley-Liss, Inc.

  16. FAS-ligand regulates differential activation-induced cell death of human T-helper 1 and 17 cells in healthy donors and multiple sclerosis patients.

    Science.gov (United States)

    Cencioni, M T; Santini, S; Ruocco, G; Borsellino, G; De Bardi, M; Grasso, M G; Ruggieri, S; Gasperini, C; Centonze, D; Barilá, D; Battistini, L; Volpe, E

    2015-05-07

    Functionally distinct T-helper (Th) subsets orchestrate immune responses. Maintenance of homeostasis through the tight control of inflammatory Th cells is crucial to avoid autoimmune inflammation. Activation-Induced Cell Death (AICD) regulates homeostasis of T cells, and it has never been investigated in human Th cells. We generated stable clones of inflammatory Th subsets involved in autoimmune diseases, such as Th1, Th17 and Th1/17 cells, from healthy donors (HD) and multiple sclerosis (MS) patients and we measured AICD. We find that human Th1 cells are sensitive, whereas Th17 and Th1/17 are resistant, to AICD. In particular, Th1 cells express high level of FAS-ligand (FASL), which interacts with FAS and leads to caspases' cleavage and ultimately to cell death. In contrast, low FASL expression in Th17 and Th1/17 cells blunts caspase 8 activation and thus reduces cell death. Interestingly, Th cells obtained from healthy individuals and MS patients behave similarly, suggesting that this mechanism could explain the persistence of inflammatory IL-17-producing cells in autoimmune diseases, such as MS, where their generation is particularly substantial.

  17. Cell death in the cardiovascular system

    Science.gov (United States)

    Clarke, Murray; Bennett, Martin; Littlewood, Trevor

    2007-01-01

    Cell death is important for both development and tissue homeostasis in the adult. As such, it is tightly controlled and deregulation is associated with diverse pathologies; for example, regulated cell death is involved in vessel remodelling during development or following injury, but deregulated death is implicated in pathologies such as atherosclerosis, aneurysm formation, ischaemic and dilated cardiomyopathies and infarction. We describe the mechanisms of cell death and its role in the normal physiology and various pathologies of the cardiovascular system. PMID:16547202

  18. Ricinosomes: an organelle for developmentally regulated programmed cell death in senescing plant tissues

    Science.gov (United States)

    Gietl, C.; Schmid, M.

    2001-02-01

    This review describes aspects of programmed cell death (PCD). Present research maps the enzymes involved and explores the signal transduction pathways involved in their synthesis. A special organelle (the ricinosome) has been discovered in the senescing endosperm of germinating castor beans (Ricinus communis) that develops at the beginning of PCD and delivers large amounts of a papain-type cysteine endopeptidase (CysEP) in the final stages of cellular disintegration. Castor beans store oil and proteins in a living endosperm surrounding the cotyledons. These stores are mobilized during germination and transferred into the cotyledons. PCD is initiated after this transfer is complete. The CysEP is synthesized in the lumen of the endoplasmic reticulum (ER) where it is retained by its C-terminal KDEL peptide as a rather inactive pro-enzyme. Large number of ricinosomes bud from the ER at the same time as the nuclear DNA is characteristically fragmented during PCD. The mitochondria, glyoxysomes and ribosomes are degraded in autophagic vacuoles, while the endopeptidase is activated by removal of the propeptide and the KDEL tail and enters the cytosol. The endosperm dries and detaches from the cotyledons. A homologous KDEL-tailed cysteine endopeptidase has been found in several senescing tissues; it has been localized in ricinosomes of withering day-lily petals and dying seed coats. Three genes for a KDEL-tailed cysteine endopeptidase have been identified in Arabidopsis. One is expressed in senescing ovules, the second in the vascular vessels and the third in maturing siliques. These genes open the way to exploring PCD in plants.

  19. UNBS1450 from Calotropis procera as a regulator of signaling pathways involved in proliferation and cell death.

    Science.gov (United States)

    Juncker, Tom; Schumacher, Marc; Dicato, Mario; Diederich, Marc

    2009-07-01

    Despite significant progress in oncology therapeutics in the last decades, the urge to discover and to develop new, alternative or synergistic anti-cancer agents still remains. For centuries it has been known that the coarse shrub Calotropis procera is a very promising source of ascaricidal, schizonticidal, anti-bacterial, anthelmintic, insecticidal, anti-inflammatory, anti-diarrhoeal, larvicidal and cytotoxic chemicals. Different compounds like norditerpenic esters, organic carbonates, the cysteine protease procerain, alkaloids, flavonoids, sterols as well as numerous types of cardenolides have provided this plant for centuries with scientists' interest. The chemical class of cardenolides and their related bioactivity evaluation and structure-activity relationship (SAR) studies pointed out their therapeutic utility and led to the discovery of promising drug candidates. Recently the cardiotonic steroid UNBS1450 01 (derived from 2-oxovoruscharin 02) from C. procera was shown to additionally exert an anti-cancer activity. UNBS1450 01 has been proven to be a potent sodium pump inhibitor, showing anti-proliferative and cell death-inducing activities. This anti-cancer potential of UNBS1450 01 is achieved by disorganization of the actin cytoskeleton after binding to the sodium pump at the cellular membrane, by inducing autophagy-related cell death, by repressing NF-kappaB activation as well as by down-regulating c-Myc in cancer cells. We aim to review pharmacologically important chemical extracts from C. procera and focus more specifically on the anti-cancer activities of UNBS1450 01.

  20. T-bet regulates differentiation of forkhead box protein 3+ regulatory T cells in programmed cell death-1-deficient mice

    Science.gov (United States)

    Tahara, M; Kondo, Y; Yokosawa, M; Tsuboi, H; Takahashi, S; Shibayama, S; Matsumoto, I; Sumida, T

    2015-01-01

    Programmed cell death-1 (PD-1) plays an important role in peripheral T cell tolerance, but whether or not it affects the differentiation of helper T cell subsets remains elusive. Here we describe the importance of PD-1 in the control of T helper type 1 (Th1) cell activation and development of forkhead box protein 3 (FoxP3+) regulatory T cells (Tregs). PD-1-deficient T cell-specific T-bet transgenic (P/T) mice showed growth retardation, and the majority died within 10 weeks. P/T mice showed T-bet over-expression, increased interferon (IFN)-γ production by CD4+ T cells and significantly low FoxP3+ Treg cell percentage. P/T mice developed systemic inflammation, which was probably induced by augmented Th1 response and low FoxP3+ Treg count. The study identified a unique, previously undescribed role for PD-1 in Th1 and Treg differentiation, with potential implication in the development of Th1 cell-targeted therapy. PMID:25219397

  1. Exogenous NAD+ decreases oxidative stress and protects H2O2-treated RPE cells against necrotic death through the up-regulation of autophagy

    Science.gov (United States)

    Zhu, Ying; Zhao, Ke-ke; Tong, Yao; Zhou, Ya-li; Wang, Yi-xiao; Zhao, Pei-quan; Wang, Zhao-yang

    2016-01-01

    Increased oxidative stress, which can lead to the retinal pigment epithelium (RPE) cell death by inducing ATP depletion and DNA repair, is believed to be a prominent pathology in age-related macular degeneration (AMD). In the present study, we showed that and 0.1 mM nicotinamide adenine dinucleotide (NAD+) administration significantly blocked RPE cell death induced by 300 μM H2O2. Further investigation showed that H2O2 resulted in increased intracellular ROS level, activation of PARP-1 and subsequently necrotic death of RPE cells. Exogenous NAD+ administration significantly decreased intracellular and intranuclear ROS levels in H2O2-treated RPE cells. In addition, NAD+ administration to H2O2-treated RPE cells inhibited the activation of PARP-1 and protected the RPE cells against necrotic death. Moreover, exogenous NAD+ administration up-regulated autophagy in the H2O2-treated RPE cells. Inhibition of autophagy by LY294002 blocked the decrease of intracellular and intranuclear ROS level. Besides, inhibition of autophagy by LY294002 abolished the protection of exogenous NAD+ against H2O2-induced cell necrotic death. Taken together, our findings indicate that that exogenous NAD+ administration suppresses H2O2-induced oxidative stress and protects RPE cells against PARP-1 mediated necrotic death through the up-regulation of autophagy. The results suggest that exogenous NAD+ administration might be potential value for the treatment of AMD. PMID:27240523

  2. Exogenous NAD(+) decreases oxidative stress and protects H2O2-treated RPE cells against necrotic death through the up-regulation of autophagy.

    Science.gov (United States)

    Zhu, Ying; Zhao, Ke-Ke; Tong, Yao; Zhou, Ya-Li; Wang, Yi-Xiao; Zhao, Pei-Quan; Wang, Zhao-Yang

    2016-05-31

    Increased oxidative stress, which can lead to the retinal pigment epithelium (RPE) cell death by inducing ATP depletion and DNA repair, is believed to be a prominent pathology in age-related macular degeneration (AMD). In the present study, we showed that and 0.1 mM nicotinamide adenine dinucleotide (NAD(+)) administration significantly blocked RPE cell death induced by 300 μM H2O2. Further investigation showed that H2O2 resulted in increased intracellular ROS level, activation of PARP-1 and subsequently necrotic death of RPE cells. Exogenous NAD(+) administration significantly decreased intracellular and intranuclear ROS levels in H2O2-treated RPE cells. In addition, NAD(+) administration to H2O2-treated RPE cells inhibited the activation of PARP-1 and protected the RPE cells against necrotic death. Moreover, exogenous NAD(+) administration up-regulated autophagy in the H2O2-treated RPE cells. Inhibition of autophagy by LY294002 blocked the decrease of intracellular and intranuclear ROS level. Besides, inhibition of autophagy by LY294002 abolished the protection of exogenous NAD(+) against H2O2-induced cell necrotic death. Taken together, our findings indicate that that exogenous NAD(+) administration suppresses H2O2-induced oxidative stress and protects RPE cells against PARP-1 mediated necrotic death through the up-regulation of autophagy. The results suggest that exogenous NAD(+) administration might be potential value for the treatment of AMD.

  3. Down-Regulation of Lncrna MALAT1 Attenuates Neuronal Cell Death Through Suppressing Beclin1-Dependent Autophagy by Regulating Mir-30a in Cerebral Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Dong Guo

    2017-08-01

    Full Text Available Background/Aims: LncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1 was reported to be highly expressed in an in vitro mimic of ischemic stroke conditions. However, the exact biological role of MALAT1 and its underlying mechanism in ischemic stroke remain to be elucidated. Methods: The roles of MALAT1 and miR-30a on cell death and infarct volume and autophagy were evaluated in experimental ischemic stroke. The relationships between miR-30a and MALAT1, Beclin1 were confirmed by luciferase reporter assay. The autophagy inhibitor 3-methyadenine (3-MA was used to examine the impact of autophagy on ischemic injury. Results: We found that MALAT1, along with the levels of conversion from autophagy-related protein microtubule-associated protein light chain 3-I (LC3-I to LC3-phosphatidylethanolamine conjugate (LC3-II, as well as Beclin1 were up-regulated and miR-30a was down-regulated in cerebral cortex neurons after oxygen-glucose deprivation (OGD and mouse brain cortex after middle cerebral artery occlusion-reperfusion (MCAO. Down-regulation of MALAT1 suppressed ischemic injury and autophagy in vitro and in vivo. Furthermore, MALAT1 may serve as a molecular sponge for miR-30a and negatively regulate its expression. In addition, MALAT1 overturned the inhibitory effect of miR-30a on ischemic injury and autophagy in vitro and in vivo, which might be involved in the derepression of Beclin1, a direct target of miR-30a. Mechanistic analyses further revealed that autophagy inhibitor 3-methyadenine (3-MA markedly suppressed OGD-induced neuronal cell death and MCAO-induced ischemic brain infarction. Conclusion: Taken together, our study first revealed that down-regulation of MALAT1 attenuated neuronal cell death through suppressing Beclin1-dependent autophagy by regulating miR-30a expression in cerebral ischemic stroke. Besides, our study demonstrated a novel lncRNA-miRNA-mRNA regulatory network that is MALAT1-miR-30a-Beclin1 in ischemic

  4. THAP5 is a DNA-binding transcriptional repressor that is regulated in melanoma cells during DNA damage-induced cell death

    Energy Technology Data Exchange (ETDEWEB)

    Balakrishnan, Meenakshi P.; Cilenti, Lucia; Ambivero, Camilla [Biomolecular Science Center, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL (United States); Goto, Yamafumi [Department of Dermatology, Shinshu University School of Medicine, Matsumoto (Japan); Takata, Minoru [Department of Dermatology, Okayama University Graduate School of Medical Dentistry and Pharmaceutical Sciences, Okayama (Japan); Turkson, James; Li, Xiaoman Shawn [Biomolecular Science Center, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL (United States); Zervos, Antonis S., E-mail: azervos@mail.ucf.edu [Biomolecular Science Center, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL (United States)

    2011-01-07

    Research highlights: {yields} THAP5 is a DNA-binding protein and a transcriptional repressor. {yields} THAP5 is induced in melanoma cells upon exposure to UV or treatment with cisplatin. {yields} THAP5 induction correlates with the degree of apoptosis in melanoma cell population. {yields} THAP5 is a pro-apoptotic protein involved in melanoma cell death. -- Abstract: THAP5 was originally isolated as a specific interactor and substrate of the mitochondrial pro-apoptotic Omi/HtrA2 protease. It is a human zinc finger protein characterized by a restricted pattern of expression and the lack of orthologs in mouse and rat. The biological function of THAP5 is unknown but our previous studies suggest it could regulate G2/M transition in kidney cells and could be involved in human cardiomyocyte cell death associated with coronary artery disease (CAD). In this report, we expanded our studies on the properties and function of THAP5 in human melanoma cells. THAP5 was expressed in primary human melanocytes as well as in all melanoma cell lines that were tested. THAP5 protein level was significantly induced by UV irradiation or cisplatin treatment, conditions known to cause DNA damage. The induction of THAP5 correlated with a significant increase in apoptotic cell death. In addition, we show that THAP5 is a nuclear protein that could recognize and bind a specific DNA motif. THAP5 could also repress the transcription of a reporter gene in a heterologous system. Our work suggests that THAP5 is a DNA-binding protein and a transcriptional repressor. Furthermore, THAP5 has a pro-apoptotic function and it was induced in melanoma cells under conditions that promoted cell death.

  5. Heat shock transcription factors regulate heat induced cell death in a ...

    Indian Academy of Sciences (India)

    2007-03-29

    Hsps) which is strictly regulated by different members of heat shock transcription factors (HSFs). We previously reported that a rat histiocytoma, BC-8 failed to synthesize Hsps when subjected to typical heat shock conditions (42°C, ...

  6. Programmed Cell Death in Neurospora crassa

    Directory of Open Access Journals (Sweden)

    A. Pedro Gonçalves

    2014-01-01

    Full Text Available Programmed cell death has been studied for decades in mammalian cells, but simpler organisms, including prokaryotes, plants, and fungi, also undergo regulated forms of cell death. We highlight the usefulness of the filamentous fungus Neurospora crassa as a model organism for the study of programmed cell death. In N. crassa, cell death can be triggered genetically due to hyphal fusion between individuals with different allelic specificities at het loci, in a process called “heterokaryon incompatibility.” Chemical induction of cell death can also be achieved upon exposure to death-inducing agents like staurosporine, phytosphingosine, or hydrogen peroxide. A summary of the recent advances made by our and other groups on the discovery of the mechanisms and mediators underlying the process of cell death in N. crassa is presented.

  7. Programmed Cell Death During Caenorhabditis elegans Development

    Science.gov (United States)

    Conradt, Barbara; Wu, Yi-Chun; Xue, Ding

    2016-01-01

    Programmed cell death is an integral component of Caenorhabditis elegans development. Genetic and reverse genetic studies in C. elegans have led to the identification of many genes and conserved cell death pathways that are important for the specification of which cells should live or die, the activation of the suicide program, and the dismantling and removal of dying cells. Molecular, cell biological, and biochemical studies have revealed the underlying mechanisms that control these three phases of programmed cell death. In particular, the interplay of transcriptional regulatory cascades and networks involving multiple transcriptional regulators is crucial in activating the expression of the key death-inducing gene egl-1 and, in some cases, the ced-3 gene in cells destined to die. A protein interaction cascade involving EGL-1, CED-9, CED-4, and CED-3 results in the activation of the key cell death protease CED-3, which is tightly controlled by multiple positive and negative regulators. The activation of the CED-3 caspase then initiates the cell disassembly process by cleaving and activating or inactivating crucial CED-3 substrates; leading to activation of multiple cell death execution events, including nuclear DNA fragmentation, mitochondrial elimination, phosphatidylserine externalization, inactivation of survival signals, and clearance of apoptotic cells. Further studies of programmed cell death in C. elegans will continue to advance our understanding of how programmed cell death is regulated, activated, and executed in general. PMID:27516615

  8. Programmed Cell Death During Caenorhabditis elegans Development.

    Science.gov (United States)

    Conradt, Barbara; Wu, Yi-Chun; Xue, Ding

    2016-08-01

    Programmed cell death is an integral component of Caenorhabditis elegans development. Genetic and reverse genetic studies in C. elegans have led to the identification of many genes and conserved cell death pathways that are important for the specification of which cells should live or die, the activation of the suicide program, and the dismantling and removal of dying cells. Molecular, cell biological, and biochemical studies have revealed the underlying mechanisms that control these three phases of programmed cell death. In particular, the interplay of transcriptional regulatory cascades and networks involving multiple transcriptional regulators is crucial in activating the expression of the key death-inducing gene egl-1 and, in some cases, the ced-3 gene in cells destined to die. A protein interaction cascade involving EGL-1, CED-9, CED-4, and CED-3 results in the activation of the key cell death protease CED-3, which is tightly controlled by multiple positive and negative regulators. The activation of the CED-3 caspase then initiates the cell disassembly process by cleaving and activating or inactivating crucial CED-3 substrates; leading to activation of multiple cell death execution events, including nuclear DNA fragmentation, mitochondrial elimination, phosphatidylserine externalization, inactivation of survival signals, and clearance of apoptotic cells. Further studies of programmed cell death in C. elegans will continue to advance our understanding of how programmed cell death is regulated, activated, and executed in general. Copyright © 2016 by the Genetics Society of America.

  9. MicroRNA-183 promotes cell proliferation via regulating programmed cell death 6 in pediatric acute myeloid leukemia.

    Science.gov (United States)

    Wang, Xiang; Zuo, Dongjian; Yuan, Yufang; Yang, Xiaochun; Hong, Ze; Zhang, Rongrong

    2017-01-01

    The aim of this study was to investigate roles of microRNA (miR)-183 in pediatric acute myeloid leukemia (AML). miR-183 expression in bone marrow and patients' sera of childhood AML was detected by real-time quantitative PCR. Functions of miR-183 in malignant phenotypes of two leukemia cell lines were then evaluated. Additionally, putative targets of miR-183 were predicted using three miRNA target prediction algorithms and validated by luciferase reporter assay. Clinical relevance of miR-183 and its target gene were further determined. miR-183 expression in bone marrow and patients' sera of childhood AML was both significantly higher than those in the corresponding normal controls (both P leukemia cells. Bioinformatics prediction and luciferase reporter assay identified programmed cell death 6 (PDCD6) as a direct target gene of miR-183. Moreover, high serum miR-183 combined with low serum PDCD6 mRNA was significantly associated with French-American-British classification subtype M7 (P = 0.01) and unfavorable karyotypes (P = 0.006). Further multivariate analysis identified the combination of serum miR-183 and PDCD6 levels as an independent prognostic factor for both relapse-free and overall survivals. Functionally, re-introduction of PDCD6 markedly reversed the effects of miR-183 in cell cycle, proliferation and apoptosis of two leukemia cell lines. Combined serum miR-183 and PDCD6 mRNA may serve as a novel prognostic biomarker for pediatric AML. Interestingly, miR-183 may function as an oncogene and may enhance cell proliferation by targeting PDCD6, implying a potential therapeutic target for this malignancy.

  10. Carnitine sensitizes TRAIL-resistant cancer cells to TRAIL-induced apoptotic cell death through the up-regulation of Bax.

    Science.gov (United States)

    Park, So Jung; Park, Seong Ho; Kim, Joo-Oh; Kim, Jung Ho; Park, So Jung; Hwang, Jung Jin; Jin, Dong-Hoon; Jeong, Seong-Yun; Lee, Seung Jin; Kim, Jin Cheon; Kim, Inki; Cho, Dong-Hyung

    2012-11-09

    Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor family with apoptosis-inducing activity. Given that TRAIL selectively induces cell death in various tumors but has little or no toxicity to normal cells, TRAIL agonists have been considered as promising anti-cancer therapeutic agents. However, the resistance of many primary tumors and cancer cells to TRAIL poses a challenge. In our present study, we found that carnitine, a metabolite that transfers long-chain fatty acids into mitochondria for beta-oxidation and modulates protein kinase C activity, sensitizes TRAIL-resistant cancer cells to TRAIL. Combination of carnitine and TRAIL was found to synergistically induce apoptotic cell death through caspase activation, which was blocked by a pan caspase inhibitor, but not by an inhibitor of autophagy or an inhibitor of necrosis. The combination of carnitine and TRAIL reversed the resistance to TRAIL in lung cancer cells, colon carcinoma cells, and breast carcinoma cells. We further demonstrate that carnitine, either alone or in combination with TRAIL, enhances the expression of the pro-apoptotic Bcl-2 family protein, Bcl-2-associated X protein (Bax). The down-regulation of Bax expression by small interfering RNA reduced caspase activation when cells were treated with TRAIL, and experiments with cells from Bax knockout mice confirmed this result. Taken together, our current results suggest that carnitine can reverse the resistance of cancer cells to TRAIL by up-regulating Bax expression. Thus, a combined delivery of carnitine and TRAIL may represent a new therapeutic strategy to treat TRAIL-resistant cancer cells. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Programmed cell death in aging.

    Science.gov (United States)

    Tower, John

    2015-09-01

    Programmed cell death (PCD) pathways, including apoptosis and regulated necrosis, are required for normal cell turnover and tissue homeostasis. Mis-regulation of PCD is increasingly implicated in aging and aging-related disease. During aging the cell turnover rate declines for several highly-mitotic tissues. Aging-associated disruptions in systemic and inter-cell signaling combined with cell-autonomous damage and mitochondrial malfunction result in increased PCD in some cell types, and decreased PCD in other cell types. Increased PCD during aging is implicated in immune system decline, skeletal muscle wasting (sarcopenia), loss of cells in the heart, and neurodegenerative disease. In contrast, cancer cells and senescent cells are resistant to PCD, enabling them to increase in abundance during aging. PCD pathways limit life span in fungi, but whether PCD pathways normally limit adult metazoan life span is not yet clear. PCD is regulated by a balance of negative and positive factors, including the mitochondria, which are particularly subject to aging-associated malfunction. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Heat shock transcription factors regulate heat induced cell death in a ...

    Indian Academy of Sciences (India)

    Madhu Sudhan

    2007-03-29

    Mar 29, 2007 ... Further, proteasome inhibition increased basal levels of HSF2 expression, which was further enhanced by heat shock (figure 4A2). To understand the importance of HSFs in the activation of heat induced autophagy, siRNA for both HSF1 and HSF2 were made and BC-8 cells were treated with these oligos.

  13. Tat-HSP22 inhibits oxidative stress-induced hippocampal neuronal cell death by regulation of the mitochondrial pathway.

    Science.gov (United States)

    Jo, Hyo Sang; Kim, Dae Won; Shin, Min Jea; Cho, Su Bin; Park, Jung Hwan; Lee, Chi Hern; Yeo, Eun Ji; Choi, Yeon Joo; Yeo, Hyeon Ji; Sohn, Eun Jeong; Son, Ora; Cho, Sung-Woo; Kim, Duk-Soo; Yu, Yeon Hee; Lee, Keun Wook; Park, Jinseu; Eum, Won Sik; Choi, Soo Young

    2017-01-04

    Oxidative stress plays an important role in the progression of various neuronal diseases including ischemia. Heat shock protein 22 (HSP22) is known to protect cells against oxidative stress. However, the protective effects and mechanisms of HSP22 in hippocampal neuronal cells under oxidative stress remain unknown. In this study, we determined whether HSP22 protects against hydrogen peroxide (H2O2)-induced oxidative stress in HT-22 using Tat-HSP22 fusion protein. We found that Tat-HSP22 transduced into HT-22 cells and that H2O2-induced cell death, oxidative stress, and DNA damage were significantly reduced by Tat-HSP22. In addition, Tat-HSP22 markedly inhibited H2O2-induced mitochondrial membrane potential, cytochrome c release, cleaved caspase-3, and Bax expression levels, while Bcl-2 expression levels were increased in HT-22 cells. Further, we showed that Tat-HSP22 transduced into animal brain and inhibited cleaved-caspase-3 expression levels as well as significantly inhibited hippocampal neuronal cell death in the CA1 region of animals in the ischemic animal model. In the present study, we demonstrated that transduced Tat-HSP22 attenuates oxidative stress-induced hippocampal neuronal cell death through the mitochondrial signaling pathway and plays a crucial role in inhibiting neuronal cell death, suggesting that Tat-HSP22 protein may be used to prevent oxidative stress-related brain diseases including ischemia.

  14. Valproic acid inhibits neural progenitor cell death by activation of NF-κB signaling pathway and up-regulation of Bcl-XL

    Directory of Open Access Journals (Sweden)

    Han Seol

    2011-07-01

    Full Text Available Abstract Background At the beginning of neurogenesis, massive brain cell death occurs and more than 50% of cells are eliminated by apoptosis along with neuronal differentiation. However, few studies were conducted so far regarding the regulation of neural progenitor cells (NPCs death during development. Because of the physiological role of cell death during development, aberration of normal apoptotic cell death is detrimental to normal organogenesis. Apoptosis occurs in not only neuron but also in NPCs and neuroblast. When growth and survival signals such as EGF or LIF are removed, apoptosis is activated as well as the induction of differentiation. To investigate the regulation of cell death during developmental stage, it is essential to investigate the regulation of apoptosis of NPCs. Methods Neural progenitor cells were cultured from E14 embryonic brains of Sprague-Dawley rats. For in vivo VPA animal model, pregnant rats were treated with VPA (400 mg/kg S.C. diluted with normal saline at E12. To analyze the cell death, we performed PI staining and PARP and caspase-3 cleavage assay. Expression level of proteins was investigated by Western blot and immunocytochemical assays. The level of mRNA expression was investigated by RT-PCR. Interaction of Bcl-XL gene promoter and NF-κB p65 was investigated by ChIP assay. Results In this study, FACS analysis, PI staining and PARP and caspase-3 cleavage assay showed that VPA protects cultured NPCs from cell death after growth factor withdrawal both in basal and staurosporine- or hydrogen peroxide-stimulated conditions. The protective effect of prenatally injected VPA was also observed in E16 embryonic brain. Treatment of VPA decreased the level of IκBα and increased the nuclear translocation of NF-κB, which subsequently enhanced expression of anti-apoptotic protein Bcl-XL. Conclusion To the best of our knowledge, this is the first report to indicate the reduced death of NPCs by VPA at developmentally

  15. Up-regulation of TRPV1 in mononuclear cells of end-stage kidney disease patients increases susceptibility to N-arachidonoyl-dopamine (NADA)-induced cell death.

    Science.gov (United States)

    Saunders, Cassandra I; Fassett, Robert G; Geraghty, Dominic P

    2009-10-01

    Transient receptor potential vanilloid (TRPV) 1 channels function as sensors for a variety of noxious and inflammatory signals, including capsaicin, heat and protons, and are up-regulated under inflammatory conditions. As end-stage kidney disease (ESKD) is associated with chronic inflammation, impaired immunity and depressed lymphocyte numbers, we sought to determine whether altered TRPV1 (and related TRPV2) expression in immune cells might be a contributing factor. TRPV1 and TRPV2 mRNA expression in peripheral blood mononuclear cells (PBMC) was similar in controls and ESKD patients by quantitative real-time RT-PCR. However, using immunocytochemistry, TRPV1-immunoreactivity was significantly higher and TRPV2-immunoreactivity was significantly lower in PBMC from ESKD patients compared to controls. The plant-derived TRPV1 agonists, capsaicin and resiniferatoxin (RTX) and the putative endovanilloid/endocannabinoids, N-arachidonoyl-dopamine (NADA) and N-oleoyl-dopamine (OLDA), induced concentration-dependent death of PBMC from healthy donors with a rank order of potency of RTX>NADA>OLDA>capsaicin. TRPV1 (5'-iodoresiniferatoxin) and cannabinoid (CB2; AM630) receptor antagonists blocked the cytotoxic effect of NADA. In subsequent experiments, PBMC from ESKD patients exhibited significantly increased susceptibility to NADA-induced death compared to PBMC from controls. The apparent up-regulation of TRPV1 may be a response to the inflammatory milieu in which PBMC exist in ESKD and may be responsible for the increased susceptibility of these cells to NADA-induced death, providing a possible explanation as to why ESKD patients have reduced lymphocyte counts and impaired immune function. Thus, TRPV1 (and possibly CB2) antagonists may have potential for the treatment of immune dysfunction in ESKD.

  16. Dead Cert: Measuring Cell Death.

    Science.gov (United States)

    Crowley, Lisa C; Marfell, Brooke J; Scott, Adrian P; Boughaba, Jeanne A; Chojnowski, Grace; Christensen, Melinda E; Waterhouse, Nigel J

    2016-12-01

    Many cells in the body die at specific times to facilitate healthy development or because they have become old, damaged, or infected. Defects in cells that result in their inappropriate survival or untimely death can negatively impact development or contribute to a variety of human pathologies, including cancer, AIDS, autoimmune disorders, and chronic infection. Cell death may also occur following exposure to environmental toxins or cytotoxic chemicals. Although this is often harmful, it can be beneficial in some cases, such as in the treatment of cancer. The ability to objectively measure cell death in a laboratory setting is therefore essential to understanding and investigating the causes and treatments of many human diseases and disorders. Often, it is sufficient to know the extent of cell death in a sample; however, the mechanism of death may also have implications for disease progression, treatment, and the outcomes of experimental investigations. There are a myriad of assays available for measuring the known forms of cell death, including apoptosis, necrosis, autophagy, necroptosis, anoikis, and pyroptosis. Here, we introduce a range of assays for measuring cell death in cultured cells, and we outline basic techniques for distinguishing healthy cells from apoptotic or necrotic cells-the two most common forms of cell death. We also provide personal insight into where these assays may be useful and how they may or may not be used to distinguish apoptotic cell death from other death modalities. © 2016 Cold Spring Harbor Laboratory Press.

  17. Zfra affects TNF-mediated cell death by interacting with death domain protein TRADD and negatively regulates the activation of NF-κB, JNK1, p53 and WOX1 during stress response

    Directory of Open Access Journals (Sweden)

    Pratt Nicole

    2007-06-01

    Full Text Available Abstract Background Zfra is a 31-amino-acid zinc finger-like protein, which is known to regulate cell death by tumor necrosis factor (TNF and overexpressed TNF receptor- or Fas-associated death domain proteins (TRADD and FADD. In addition, Zfra undergoes self-association and interacts with c-Jun N-terminal kinase 1 (JNK1 in response to stress stimuli. To further delineate the functional properties of Zfra, here we investigated Zfra regulation of the activation of p53, WOX1 (WWOX or FOR, NF-κB, and JNK1 under apoptotic stress. Results Transiently overexpressed Zfra caused growth suppression and apoptotic death of many but not all types of cells. Zfra either enhanced or blocked cell death caused by TRADD, FADD, or receptor-interacting protein (RIP in a dose-related manner. This modulation is related with Zfra binding with TRADD, NF-κB, JNK1 and WOX1, as determined by GST pull-down analysis, co-immunoprecipitation, and mapping by yeast two-hybrid analysis. Functionally, transiently overexpressed Zfra sequestered NF-κB (p65, WOX1, p53 and phospho-ERK (extracellular signal-activated kinase in the cytoplasm, and TNF or UV light could not effectively induce nuclear translocation of these proteins. Zfra counteracted the apoptotic functions of Tyr33-phosphorylated WOX1 and Ser46-phosphorylated p53. Alteration of Ser8 to Gly abolished the apoptotic function of Zfra and its regulation of WOX1 and p53. Conclusion In response to TNF, Zfra is upregulated and modulates TNF-mediated cell death via interacting with TRADD, FADD and RIP (death-inducing signaling complex at the receptor level, and downstream effectors NF-κB, p53, WOX1, and JNK1.

  18. Deletion Of XIAP reduces the severity of acute pancreatitis via regulation of cell death and nuclear factor-κB activity.

    Science.gov (United States)

    Liu, Yong; Chen, Xiao-Dong; Yu, Jiang; Chi, Jun-Lin; Long, Fei-Wu; Yang, Hong-Wei; Chen, Ke-Ling; Lv, Zhao-Ying; Zhou, Bin; Peng, Zhi-Hai; Sun, Xiao-Feng; Li, Yuan; Zhou, Zong-Guang

    2017-03-16

    Severe acute pancreatitis (SAP) still remains a clinical challenge, not only for its high mortality but the uncontrolled inflammatory progression from acute pancreatitis (AP) to SAP. Cell death, including apoptosis and necrosis are critical pathology of AP, since the severity of pancreatitis correlates directly with necrosis and inversely with apoptosis Therefore, regulation of cell death from necrosis to apoptosis may have practicably therapeutic value. X-linked inhibitor of apoptosis protein (XIAP) is the best characterized member of the inhibitor of apoptosis proteins (IAP) family, but its function in AP remains unclear. In the present study, we investigated the potential role of XIAP in regulation of cell death and inflammation during acute pancreatitis. The in vivo pancreatitis model was induced by the administration of cerulein with or without lipopolysaccharide (LPS) or by the administration of l-arginine in wild-type or XIAP-deficient mice, and ex vivo model was induced by the administration of cerulein+LPS in AR42J cell line following XIAP inhibition. The severity of acute pancreatitis was determined by serum amylase activity and histological grading. XIAP deletion on cell apoptosis, necrosis and inflammatory response were examined. Caspases activities, nuclear factor-κB (NF-κB) activation and receptor-interacting protein kinase1 (RIP1) degradation were assessed by western blot. Deletion of XIAP resulted in the reduction of amylase activity, decrease of NF-κB activation and less release of TNF-α and IL-6, together with increased caspases activities and RIP1 degradation, leading to enhanced apoptosis and reduced necrosis in pancreatic acinar cells and ameliorated the severity of acute pancreatitis. Our results indicate that deletion of XIAP switches cell death away from necrosis to apoptosis and decreases the inflammatory response, effectively attenuating the severity of AP/SAP. The critical role of XIAP in cell death and inflammation suggests that

  19. Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells.

    Science.gov (United States)

    Tiptiri-Kourpeti, Angeliki; Spyridopoulou, Katerina; Santarmaki, Valentina; Aindelis, Georgios; Tompoulidou, Evgenia; Lamprianidou, Eleftheria E; Saxami, Georgia; Ypsilantis, Petros; Lampri, Evangeli S; Simopoulos, Constantinos; Kotsianidis, Ioannis; Galanis, Alex; Kourkoutas, Yiannis; Dimitrellou, Dimitra; Chlichlia, Katerina

    2016-01-01

    Probiotic microorganisms such as lactic acid bacteria (LAB) exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof) on murine (CT26) and human (HT29) colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 10(9) CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells). In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 10(9) CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain.

  20. Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells.

    Directory of Open Access Journals (Sweden)

    Angeliki Tiptiri-Kourpeti

    Full Text Available Probiotic microorganisms such as lactic acid bacteria (LAB exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof on murine (CT26 and human (HT29 colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 10(9 CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells. In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 10(9 CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain.

  1. Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells

    Science.gov (United States)

    Santarmaki, Valentina; Aindelis, Georgios; Tompoulidou, Evgenia; Lamprianidou, Eleftheria E.; Saxami, Georgia; Ypsilantis, Petros; Lampri, Evangeli S.; Simopoulos, Constantinos; Kotsianidis, Ioannis; Galanis, Alex; Kourkoutas, Yiannis; Dimitrellou, Dimitra; Chlichlia, Katerina

    2016-01-01

    Probiotic microorganisms such as lactic acid bacteria (LAB) exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof) on murine (CT26) and human (HT29) colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 109 CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells). In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 109 CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain. PMID:26849051

  2. Down-regulation of alpha-synuclein expression can rescue dopaminergic cells from cell death in the substantia nigra of Parkinson's disease rat model.

    Science.gov (United States)

    Hayashita-Kinoh, Hiromi; Yamada, Masanori; Yokota, Takanori; Mizuno, Yoshikuni; Mochizuki, Hideki

    2006-03-24

    Fibrillization and aggregation of alpha-synuclein may play a critical role in neurodegenerative diseases like Parkinson's diseases. Adeno-associated virus (AAV) vector delivery of an alpha-synuclein ribozyme was tested for its silencing effect on degenerating nigrostriatal neurons in the MPP(+) model of Parkinson's disease. We designed alpha-synuclein ribozyme against human alpha-synuclein gene expression and constructed alpha-synuclein ribozymes-carrying rAAV vector (designated rAAV-SynRz). Co-transfection of rAAV-SynRz and rAAV-alpha-synuclein into HEK293 cells resulted in down-regulation of alpha-synuclein protein expression in vitro. Then, rAAV-SynRz was injected into the substantia nigra (SN) of MPP(+)-treated rats. Cell counts of TH-positive neurons in the SN revealed that rAAV-SynRz significantly protected TH-positive cells against apoptotic death, compared with those of rAAV-EGFP or no rAAV injected rats. Our results indicate that the use of rAAV-SynRz allowed the survival of higher number of TH-positive neurons in SN in the MPP(+) model. Down-regulation of alpha-synuclein expression could be potentially a suitable target for gene therapy of Parkinson's disease.

  3. An essential role for the VASt domain of the Arabidopsis VAD1 protein in the regulation of defense and cell death in response to pathogens.

    Directory of Open Access Journals (Sweden)

    Mehdi Khafif

    Full Text Available Several regulators of programmed cell death (PCD have been identified in plants which encode proteins with putative lipid-binding domains. Among them, VAD1 (Vascular Associated Death contains a novel protein domain called VASt (VAD1 analog StAR-related lipid transfer still uncharacterized. The Arabidopsis mutant vad1-1 has been shown to exhibit a lesion mimic phenotype with light-conditional appearance of propagative hypersensitive response-like lesions along the vascular system, associated with defense gene expression and increased resistance to Pseudomonas strains. To test the potential of ectopic expression of VAD1 to influence HR cell death and to elucidate the role of the VASt domain in this function, we performed a structure-function analysis of VAD1 by transient over-expression in Nicotiana benthamiana and by complementation of the mutant vad1-1. We found that (i overexpression of VAD1 controls negatively the HR cell death and defense expression either transiently in Nicotiana benthamania or in Arabidopsis plants in response to avirulent strains of Pseudomonas syringae, (ii VAD1 is expressed in multiple subcellular compartments, including the nucleus, and (iii while the GRAM domain does not modify neither the subcellular localization of VAD1 nor its immunorepressor activity, the domain VASt plays an essential role in both processes. In conclusion, VAD1 acts as a negative regulator of cell death associated with the plant immune response and the VASt domain of this unknown protein plays an essential role in this function, opening the way for the functional analysis of VASt-containing proteins and the characterization of novel mechanisms regulating PCD.

  4. Role of DAPK in neuronal cell death.

    Science.gov (United States)

    Fujita, Yuki; Yamashita, Toshihide

    2014-02-01

    Neuronal cell death happens as a result of the normal physiological process that occurs during development, or as part of the pathological process that occurs during disease. Death-associated protein kinase (DAPK) is an intracellular protein that mediates cell death by its serine/threonine kinase activity, and transmits apoptotic cell death signals in various cells, including neurons. DAPK is elevated in injured neurons in acute models of injury such as ischemia and seizure. The absence of DAPK has been shown to protect neurons from a wide variety of acute toxic insults. Moreover, DAPK also regulates neuronal cell death during central nervous system development. Neurons are initially overproduced in the developing nervous system, following which approximately one-half of the original cell population dies. This "naturally-occurring" or "programmed" cell death is essential for the construction of the developing nervous system. In this review, we focus on the role of DAPK in neuronal cell death after neuronal injury. The participation of DAPK in developmental neuronal death is also explained.

  5. Involvement of the MAPK and PI3K pathways in chitinase 3-like 1-regulated hyperoxia-induced airway epithelial cell death

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Na; Lee, Kyung Eun; Hong, Jung Yeon; Heo, Won Il; Kim, Kyung Won; Kim, Kyu Earn [Department of Pediatrics and Institute of Allergy, Severance Medical Research Institute, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul (Korea, Republic of); Sohn, Myung Hyun, E-mail: mhsohn@yuhs.ac [Department of Pediatrics and Institute of Allergy, Severance Medical Research Institute, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2012-05-18

    , phosphorylation of ERK1/2, p38, and Akt were affected by CHI3L1 knockdown. Conclusion: This study indicates that CHI3L1 is involved in hyperoxia-induced cell death, suggesting that CHI3L1 may be one of several cell death regulators influencing the MAPK and PI3K pathways during oxidative stress in human airway epithelial cells.

  6. Anti-CD3 treatment up-regulates programmed cell death protein-1 expression on activated effector T cells and severely impairs their inflammatory capacity.

    Science.gov (United States)

    Wallberg, Maja; Recino, Asha; Phillips, Jenny; Howie, Duncan; Vienne, Margaux; Paluch, Christopher; Azuma, Miyuki; Wong, F Susan; Waldmann, Herman; Cooke, Anne

    2017-06-01

    T cells play a key role in the pathogenesis of type 1 diabetes, and targeting the CD3 component of the T-cell receptor complex provides one therapeutic approach. Anti-CD3 treatment can reverse overt disease in spontaneously diabetic non-obese diabetic mice, an effect proposed to, at least in part, be caused by a selective depletion of pathogenic cells. We have used a transfer model to further investigate the effects of anti-CD3 treatment on green fluorescent protein (GFP)(+) islet-specific effector T cells in vivo. The GFP expression allowed us to isolate the known effectors at different time-points during treatment to assess cell presence in various organs as well as gene expression and cytokine production. We find, in this model, that anti-CD3 treatment does not preferentially deplete the transferred effector cells, but instead inhibits their metabolic function and their production of interferon-γ. Programmed cell death protein 1 (PD-1) expression was up-regulated on the effector cells from anti-CD3-treated mice, and diabetes induced through anti-PD-L1 antibody could only be reversed with anti-CD3 antibody if the anti-CD3 treatment lasted beyond the point when the anti-PD-L1 antibody was washed out of the system. This suggests that PD-1/PD-L1 interaction plays an important role in the anti-CD3 antibody mediated protection. Our data demonstrate an additional mechanism by which anti-CD3 therapy can reverse diabetogenesis. © 2017 The Authors. Immunology Published by John Wiley & Sons Ltd.

  7. Demystifying MST family kinases in cell death.

    Science.gov (United States)

    Lehtinen, Maria K; Bonni, Azad

    2008-06-01

    The MST family of protein kinases plays a critical role in the regulation of cell death in diverse organisms including mammals. The intracellular signaling pathways that regulate MST-driven cell death in mammalian cells are the subject of intense investigation. Stress stimuli including oxidative stress and DNA damaging agents trigger the activity of MST in cells. Although the mechanisms by which oxidative stress and DNA damage trigger MST activation remain to be identified, MST activity can be regulated by caspase-induced cleavage as well as interactions with other proteins in cells. Once activated upon oxidative stress, MST induces cell death via phosphorylation and activation of the transcription factor FOXO3 or the histone protein H2B. This review focuses on the currently known upstream activating mechanisms for MST, and explores the downstream signaling pathways that mediate MST's principal function in cell death. Elucidation of MST functions and their regulatory mechanisms in cell death have important implications for our understanding of cellular homeostasis as well as the pathogenesis of diverse diseases.

  8. Catalase and alternative oxidase cooperatively regulate programmed cell death induced by beta-glucan elicitor in potato suspension cultures.

    Science.gov (United States)

    Mizuno, Masashi; Tada, Yasuomi; Uchii, Kimitaka; Kawakami, Sachiko; Mayama, Shigeyuki

    2005-04-01

    In potato (Solanum tuberosum L.) suspension cells, the expression of the gene encoding alternative oxidase (AOX) and H2O2 accumulation were induced by treatment with beta-glucan elicitor. The inhibition of catalase activity enhanced both AOX mRNA expression and the production of H2O2, whereas the ascorbate peroxidase inhibitor did not have any effect on these responses. Simultaneous inhibition of catalase and AOX activities in elicited cells dramatically increased H2O2 accumulation, leading to the disruption of mitochondrial membrane potential (deltapsi(m)) and programmed cell death (PCD). The results demonstrate, for the first time, that not only AOX but also catalase plays a central role in the suppression of mitochondrial deltapsi(m) breakdown and PCD induced by beta-glucan elicitor.

  9. Dahuang Zhechong Pill Combined with Doxorubicin Induces Cell Death through Regulating Energy Metabolism in Human Hepatocellular Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Li Wu

    2017-01-01

    Full Text Available Many physiological activities such as cell survival, proliferation, defense, adaptation, and metabolism need to consume energy. Hepatoma cells can quickly start stress responses like multidrug resistance (MDR requiring adenosine triphosphate (ATP consumption after administration of chemotherapeutics. We employed CCK-8 assay to evaluate cell viability and the flow cytometry to confirm apoptosis and necrosis. ELISA kit was used to determine intracellular levels of ATP in lysates. Western blot was employed to analyze the expressions of key enzymes involved in energy metabolism. We found that doxorubicin (DOX potently stimulated apoptosis at a low dose and even induced necrosis at a high dose in SMMC-7721. DHZCP combined with DOX at low or middle dose enhanced the synergistic antihepatoma effect. Results indicated that Dahuang Zhechong Pill (DHZCP inhibited the expressions of several key enzymes involved in oxidative phosphorylation and reduced intracellular ATP levels. The combination of DHZCP with DOX reversed the elevation of intracellular ATP levels, and a significantly synergistic antitumor effect was observed. DHZCP could not only strengthen the therapeutic effects of chemotherapeutic drugs but also decrease the doses of chemotherapeutic drugs and the incidences of adverse reactions, providing novel strategies for clinical treatment of liver cancer.

  10. Serum- and Glucocorticoid-induced Protein Kinase 1 (SGK1) Is Regulated by Store-operated Ca2+ Entry and Mediates Cytoprotection against Necrotic Cell Death*

    Science.gov (United States)

    Brickley, Deanna R.; Agyeman, Abena S.; Kopp, Richard F.; Hall, Ben A.; Harbeck, Mark C.; Belova, Larissa; Volden, Paul A.; Wu, Wei; Roe, Michael W.; Conzen, Suzanne D.

    2013-01-01

    Serum and glucocorticoid-regulated kinase 1 (SGK1) encodes a phosphatidylinositol 3-kinase-dependent serine/threonine kinase that is rapidly induced in response to cellular stressors and is an important cell survival signal. Previous studies have suggested that an increase in cytoplasmic Ca2+ concentration ([Ca2+]c) is required for increased SGK1 expression, but the subcellular source of Ca2+ regulating SGK1 transcription remains uncertain. Activation of endoplasmic reticulum stress (ERS) with thapsigargin (TG) increased SGK1 mRNA and protein expression in MDA-MB-231 cells. Intracellular Ca2+ imaging revealed that store-operated Ca2+ entry played a prominent role in SGK1 induction by TG. Neither ERS nor release of Ca2+ from the ER was sufficient to activate SGK1. Prolonged elevation of intracellular Ca2+ levels, however, triggered cell death with a much greater proportion of the cells undergoing necrosis rather than apoptosis. A relative increase in the percentage of cells undergoing necrosis was observed in cells expressing a short hairpin RNA targeted to the SGK1 gene. Necrotic cell death evoked by cytoplasmic Ca2+ overloading was associated with persistent hyperpolarization of the inner mitochondrial membrane and a modest increase in calpain activation, but did not involve detectable caspase 3 or caspase 7 activation. The effects of cytoplasmic Ca2+ overloading on mitochondrial membrane potential were significantly reduced in cells expressing SGK1 compared with SGK1-depleted cells. Our findings indicate that store-operated Ca2+ entry regulates SGK1 expression in epithelial cells and suggest that SGK1-dependent cytoprotective signaling involves effects on maintaining mitochondrial function. PMID:24043625

  11. Serum- and glucocorticoid-induced protein kinase 1 (SGK1) is regulated by store-operated Ca2+ entry and mediates cytoprotection against necrotic cell death.

    Science.gov (United States)

    Brickley, Deanna R; Agyeman, Abena S; Kopp, Richard F; Hall, Ben A; Harbeck, Mark C; Belova, Larissa; Volden, Paul A; Wu, Wei; Roe, Michael W; Conzen, Suzanne D

    2013-11-08

    Serum and glucocorticoid-regulated kinase 1 (SGK1) encodes a phosphatidylinositol 3-kinase-dependent serine/threonine kinase that is rapidly induced in response to cellular stressors and is an important cell survival signal. Previous studies have suggested that an increase in cytoplasmic Ca(2+) concentration ([Ca(2+)]c) is required for increased SGK1 expression, but the subcellular source of Ca(2+) regulating SGK1 transcription remains uncertain. Activation of endoplasmic reticulum stress (ERS) with thapsigargin (TG) increased SGK1 mRNA and protein expression in MDA-MB-231 cells. Intracellular Ca(2+) imaging revealed that store-operated Ca(2+) entry played a prominent role in SGK1 induction by TG. Neither ERS nor release of Ca(2+) from the ER was sufficient to activate SGK1. Prolonged elevation of intracellular Ca(2+) levels, however, triggered cell death with a much greater proportion of the cells undergoing necrosis rather than apoptosis. A relative increase in the percentage of cells undergoing necrosis was observed in cells expressing a short hairpin RNA targeted to the SGK1 gene. Necrotic cell death evoked by cytoplasmic Ca(2+) overloading was associated with persistent hyperpolarization of the inner mitochondrial membrane and a modest increase in calpain activation, but did not involve detectable caspase 3 or caspase 7 activation. The effects of cytoplasmic Ca(2+) overloading on mitochondrial membrane potential were significantly reduced in cells expressing SGK1 compared with SGK1-depleted cells. Our findings indicate that store-operated Ca(2+) entry regulates SGK1 expression in epithelial cells and suggest that SGK1-dependent cytoprotective signaling involves effects on maintaining mitochondrial function.

  12. Moderate extracellular acidification inhibits capsaicin-induced cell death through regulating calcium mobilization, NF-{kappa}B translocation and ROS production in synoviocytes

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Fen; Yang, Shuang; Zhao, Dan; Zhu, Shuyan; Wang, Yuxiang [Department of Biophysics, School of Physics and Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin 300071 (China); Li, Junying, E-mail: jyli04@nankai.edu.cn [Department of Biophysics, School of Physics and Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin 300071 (China)

    2012-07-20

    Highlights: Black-Right-Pointing-Pointer Moderate extracellular acidification regulates intracellular Ca{sup 2+} mobilization. Black-Right-Pointing-Pointer Moderate acidification activates NF-{kappa}B nuclear translocation in synoviocytes. Black-Right-Pointing-Pointer Moderate acidification depresses the ROS production induced by capsaicin. Black-Right-Pointing-Pointer Moderate acidification inhibits capsaicin-caused synoviocyte death. -- Abstract: We previously show the expression of transient receptor potential vanilloid 1 (TRPV1) in primary synoviocytes from collagen-induced arthritis (CIA) rats. Capsaicin and lowered extracellular pH from 7.4 to 5.5 induce cell death through TRPV1-mediated Ca{sup 2+} entry and reactive oxygen species (ROS) production. However, under the pathological condition in rheumatoid arthritis, the synovial fluid is acidified to a moderate level (about pH 6.8). In the present study, we examined the effects of pH 6.8 on the TRPV1-mediated cell death. Our finding is different or even opposite from what was observed at pH 5.5. We found that the moderate extracellular acidification (from pH 7.4 to 6.8) inhibited the capsaicin-induced Ca{sup 2+} entry through attenuating the activity of TRPV1. In the mean time, it triggered a phospholipse C (PLC)-related Ca{sup 2+} release from intracellular stores. The nuclear translocation of NF-{kappa}B was found at pH 6.8, and this also depends on PLC activation. Moreover, the capsaicin-evoked massive ROS production and cell death were depressed at pH 6.8, both of which are dependent on the activation of PLC and NF-{kappa}B. Taken together, these results suggested that the moderate extracellular acidification inhibited the capsaicin-induced synoviocyte death through regulating Ca{sup 2+} mobilization, activating NF-{kappa}B nuclear translocation and depressing ROS production.

  13. Reduced expression of brain-enriched microRNAs in glioblastomas permits targeted regulation of a cell death gene.

    Directory of Open Access Journals (Sweden)

    Rebecca L Skalsky

    Full Text Available Glioblastoma is a highly aggressive malignant tumor involving glial cells in the human brain. We used high-throughput sequencing to comprehensively profile the small RNAs expressed in glioblastoma and non-tumor brain tissues. MicroRNAs (miRNAs made up the large majority of small RNAs, and we identified over 400 different cellular pre-miRNAs. No known viral miRNAs were detected in any of the samples analyzed. Cluster analysis revealed several miRNAs that were significantly down-regulated in glioblastomas, including miR-128, miR-124, miR-7, miR-139, miR-95, and miR-873. Post-transcriptional editing was observed for several miRNAs, including the miR-376 family, miR-411, miR-381, and miR-379. Using the deep sequencing information, we designed a lentiviral vector expressing a cell suicide gene, the herpes simplex virus thymidine kinase (HSV-TK gene, under the regulation of a miRNA, miR-128, that was found to be enriched in non-tumor brain tissue yet down-regulated in glioblastomas, Glioblastoma cells transduced with this vector were selectively killed when cultured in the presence of ganciclovir. Using an in vitro model to recapitulate expression of brain-enriched miRNAs, we demonstrated that neuronally differentiated SH-SY5Y cells transduced with the miRNA-regulated HSV-TK vector are protected from killing by expression of endogenous miR-128. Together, these results provide an in-depth analysis of miRNA dysregulation in glioblastoma and demonstrate the potential utility of these data in the design of miRNA-regulated therapies for the treatment of brain cancers.

  14. Mdm4 (Mdmx) regulates p53-induced growth arrest and neuronal cell death during early embryonic mouse development

    DEFF Research Database (Denmark)

    Migliorini, Domenico; Lazzerini Denchi, Eros; Danovi, Davide

    2002-01-01

    characterized by overall growth deficiency, anemia, improper neural tube closure, and dilation of lateral ventricles. In situ analysis demonstrated increased levels of p21(CIP1/Waf1) and lower levels of Cyclin E and proliferating cell nuclear antigen expression. Consistent with lack of 5-bromo-2'-deoxyuridine...... central nervous system of the Mdm4 mutant embryos. These findings unambiguously assign a critical role for Mdm4 as a negative regulator of p53 and suggest that Mdm4 could contribute to neoplasias retaining wild-type Trp53. Finally, we provide evidence indicating that Mdm4 plays no role on cell...

  15. Cell death in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Webb, J.S.; Thompson, L.S.; James, S.

    2003-01-01

    Bacteria growing in biofilms often develop multicellular, three-dimensional structures known as microcolonies. Complex differentiation within biofilms of Pseudomonas aeruginosa occurs, leading to the creation of voids inside microcolonies and to the dispersal of cells from within these voids....... However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of P. aeruginosa during the normal course of development. Cell death...... occurred with temporal and spatial organization within biofilms, inside microcolonies, when the biofilms were allowed to develop in continuous-culture flow cells. A subpopulation of viable cells was always observed in these regions. During the onset of biofilm killing and during biofilm development...

  16. Genome-wide identification of genes involved in the positive and negative regulation of acetic acid-induced programmed cell death in Saccharomyces cerevisiae.

    Science.gov (United States)

    Sousa, Marlene; Duarte, Ana Marta; Fernandes, Tânia R; Chaves, Susana R; Pacheco, Andreia; Leão, Cecília; Côrte-Real, Manuela; Sousa, Maria João

    2013-11-28

    Acetic acid is mostly known as a toxic by-product of alcoholic fermentation carried out by Saccharomyces cerevisiae, which it frequently impairs. The more recent finding that acetic acid triggers apoptotic programmed cell death (PCD) in yeast sparked an interest to develop strategies to modulate this process, to improve several biotechnological applications, but also for biomedical research. Indeed, acetate can trigger apoptosis in cancer cells, suggesting its exploitation as an anticancer compound. Therefore, we aimed to identify genes involved in the positive and negative regulation of acetic acid-induced PCD by optimizing a functional analysis of a yeast Euroscarf knock-out mutant collection. The screen consisted of exposing the mutant strains to acetic acid in YPD medium, pH 3.0, in 96-well plates, and subsequently evaluating the presence of culturable cells at different time points. Several functional categories emerged as greatly relevant for modulation of acetic acid-induced PCD (e.g.: mitochondrial function, transcription of glucose-repressed genes, protein synthesis and modifications, and vesicular traffic for protection, or amino acid transport and biosynthesis, oxidative stress response, cell growth and differentiation, protein phosphorylation and histone deacetylation for its execution). Known pro-apoptotic and anti-apoptotic genes were found, validating the approach developed. Metabolism stood out as a main regulator of this process, since impairment of major carbohydrate metabolic pathways conferred resistance to acetic acid-induced PCD. Among these, lipid catabolism arose as one of the most significant new functions identified. The results also showed that many of the cellular and metabolic features that constitute hallmarks of tumour cells (such as higher glycolytic energetic dependence, lower mitochondrial functionality, increased cell division and metabolite synthesis) confer sensitivity to acetic acid-induced PCD, potentially explaining why

  17. Calcium and reactive oxygen species in regulation of the mitochondrial permeability transition and of programmed cell death in yeast.

    Science.gov (United States)

    Carraro, Michela; Bernardi, Paolo

    2016-08-01

    Mitochondria-dependent programmed cell death (PCD) in yeast shares many features with the intrinsic apoptotic pathway of mammals. With many stimuli, increased cytosolic [Ca(2+)] and ROS generation are the triggering signals that lead to mitochondrial permeabilization and release of proapoptotic factors, which initiates yeast PCD. While in mammals the permeability transition pore (PTP), a high-conductance inner membrane channel activated by increased matrix Ca(2+) and oxidative stress, is recognized as part of this signaling cascade, whether a similar process occurs in yeast is still debated. The potential role of the PTP in yeast PCD has generally been overlooked because yeast mitochondria lack the Ca(2+) uniporter, which in mammals allows rapid equilibration of cytosolic Ca(2+) with the matrix. In this short review we discuss the nature of the yeast permeability transition and reevaluate its potential role in the effector phase of yeast PCD triggered by Ca(2+) and oxidative stress. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. MEKK1 is required for MPK4 activation and regulates tissue-specific and temperature-dependent cell death in Arabidopsis.

    Science.gov (United States)

    Ichimura, Kazuya; Casais, Catarina; Peck, Scott C; Shinozaki, Kazuo; Shirasu, Ken

    2006-12-01

    Innate immunity signaling pathways in both animals and plants are regulated by mitogen-activated protein kinase (MAPK) cascades. An Arabidopsis MAPK cascade (MEKK1, MKK4/MKK5, and MPK3/MPK6) has been proposed to function downstream of the flagellin receptor FLS2 based on biochemical assays using transient overexpression of candidate components. To genetically test this model, we characterized two mekk1 mutants. We show here that MEKK1 is not required for flagellin-triggered activation of MPK3 and MPK6. Instead, MEKK1 is essential for activation of MPK4, a MAPK that negatively regulates systemic acquired resistance. We also showed that MEKK1 negatively regulates temperature-sensitive and tissue-specific cell death and H(2)O(2) accumulation that are partly dependent on both RAR1, a key component in resistance protein function, and SID2, an isochorismate synthase required for salicylic acid production upon pathogen infection.

  19. DdrO is an essential protein that regulates the radiation desiccation response and the apoptotic-like cell death in the radioresistant Deinococcus radiodurans bacterium.

    Science.gov (United States)

    Devigne, Alice; Ithurbide, Solenne; Bouthier de la Tour, Claire; Passot, Fanny; Mathieu, Martine; Sommer, Suzanne; Servant, Pascale

    2015-06-01

    Deinococcus radiodurans is known for its extreme radioresistance. Comparative genomics identified a radiation-desiccation response (RDR) regulon comprising genes that are highly induced after DNA damage and containing a conserved motif (RDRM) upstream of their coding region. We demonstrated that the RDRM sequence is involved in cis-regulation of the RDR gene ddrB in vivo. Using a transposon mutagenesis approach, we showed that, in addition to ddrO encoding a predicted RDR repressor and irrE encoding a positive regulator recently shown to cleave DdrO in Deinococcus deserti, two genes encoding α-keto-glutarate dehydrogenase subunits are involved in ddrB regulation. In wild-type cells, the DdrO cell concentration decreased transiently in an IrrE-dependent manner at early times after irradiation. Using a conditional gene inactivation system, we showed that DdrO depletion enhanced expression of three RDR proteins, consistent with the hypothesis that DdrO acts as a repressor of the RDR regulon. DdrO-depleted cells loose viability and showed morphological changes evocative of an apoptotic-like response, including membrane blebbing, defects in cell division and DNA fragmentation. We propose that DNA repair and apoptotic-like death might be two responses mediated by the same regulators, IrrE and DdrO, but differently activated depending on the persistence of IrrE-dependent DdrO cleavage. © 2015 John Wiley & Sons Ltd.

  20. The polyadenylation factor subunit CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR30: A key factor of programmed cell death and a regulator of immunity in arabidopsis

    KAUST Repository

    Bruggeman, Quentin

    2014-04-04

    Programmed cell death (PCD) is essential for several aspects of plant life, including development and stress responses. Indeed, incompatible plant-pathogen interactions are well known to induce the hypersensitive response, a localized cell death. Mutational analyses have identified several key PCD components, and we recently identified the mips1 mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for the key enzyme catalyzing the limiting step of myoinositol synthesis. One of the most striking features of mips1 is the light-dependent formation of lesions on leaves due to salicylic acid (SA)-dependent PCD, revealing roles for myoinositol or inositol derivatives in the regulation of PCD. Here, we identified a regulator of plant PCD by screening for mutants that display transcriptomic profiles opposing that of the mips1 mutant. Our screen identified the oxt6 mutant, which has been described previously as being tolerant to oxidative stress. In the oxt6 mutant, a transfer DNA is inserted in the CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR30 (CPSF30) gene, which encodes a polyadenylation factor subunit homolog. We show that CPSF30 is required for lesion formation in mips1 via SA-dependent signaling, that the prodeath function of CPSF30 is not mediated by changes in the glutathione status, and that CPSF30 activity is required for Pseudomonas syringae resistance. We also show that the oxt6 mutation suppresses cell death in other lesion-mimic mutants, including lesion-simulating disease1, mitogen-activated protein kinase4, constitutive expressor of pathogenesis-related genes5, and catalase2, suggesting that CPSF30 and, thus, the control of messenger RNA 3′ end processing, through the regulation of SA production, is a key component of plant immune responses. © 2014 American Society of Plant Biologists. All rights reserved.

  1. TRPV4 regulates insulin mRNA expression and INS-1E cell death via ERK1/2 and NO-dependent mechanisms.

    Science.gov (United States)

    Billert, M; Skrzypski, M; Sassek, M; Szczepankiewicz, D; Wojciechowicz, T; Mergler, S; Strowski, M Z; Nowak, K W

    2017-07-01

    TRPV4 is a Ca 2+ -permeable, nonselective cation channel. Recently, TRPV4 was implicated in controlling peripheral insulin sensitivity, insulin secretion and apoptosis of pancreatic beta cells. Here, we characterize the role and potential mechanisms of TRPV4 in regulating insulin mRNA expression and cell death in insulin producing INS-1E cells and rat pancreatic islets. TRPV4 protein production was downregulated by siRNA. Intracellular calcium level was measured using Fluo-3 AM. Gene expression was studied by real-time PCR. Phosphorylation of extracellular signal-regulated kinase (ERK1 and ERK2) was detected by Western blot. Nitric oxide (NO) production was assessed by chemiluminescent reaction. Reactive oxygen species (ROS) level was analysed using a fluorogenic dye (DCFDA). Cell death was evaluated by determination of cytoplasmic histone-associated DNA fragments. Downregulation of TRPV4 neither affected insulin mRNA expression nor INS-1E cell growth. By contrast, pharmacological TRPV4 activation by 100nmol/l GSK1016790A increased Ca 2+ levels in INS-1E cells and enhanced insulin mRNA expression after 1 and 3h, whereas a suppression of insulin mRNA expression was detected after 24h incubation. GSK1016790A increased ERK1/2 phosphorylation and NO production but not ROS production. Pharmacological blockade of ERK1/2 attenuated GSK1016790A-induced insulin mRNA expression. Inhibition of NO synthesis by l-NAME failed to affect insulin mRNA expression in GSK1016790A treated INS-1E cells. Furthermore, inhibition of NO production attenuated GSK1016790A-induced INS-1E cell death. In pancreatic islets, 100nmol/l GSK1016790A increased insulin mRNA levels after 3h without inducing cytotoxicity after 24h. In conclusion, TRPV4 differently regulates insulin mRNA expression in INS-1E cells via ERK1/2 and NO-dependent mechanisms. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. LUBAC-Recruited CYLD and A20 Regulate Gene Activation and Cell Death by Exerting Opposing Effects on Linear Ubiquitin in Signaling Complexes

    Directory of Open Access Journals (Sweden)

    Peter Draber

    2015-12-01

    Full Text Available Ubiquitination and deubiquitination are crucial for assembly and disassembly of signaling complexes. LUBAC-generated linear (M1 ubiquitin is important for signaling via various immune receptors. We show here that the deubiquitinases CYLD and A20, but not OTULIN, are recruited to the TNFR1- and NOD2-associated signaling complexes (TNF-RSC and NOD2-SC, at which they cooperate to limit gene activation. Whereas CYLD recruitment depends on its interaction with LUBAC, but not on LUBAC’s M1-chain-forming capacity, A20 recruitment requires this activity. Intriguingly, CYLD and A20 exert opposing effects on M1 chain stability in the TNF-RSC and NOD2-SC. While CYLD cleaves M1 chains, and thereby sensitizes cells to TNF-induced death, A20 binding to them prevents their removal and, consequently, inhibits cell death. Thus, CYLD and A20 cooperatively restrict gene activation and regulate cell death via their respective activities on M1 chains. Hence, the interplay between LUBAC, M1-ubiquitin, CYLD, and A20 is central for physiological signaling through innate immune receptors.

  3. What drives intense apoptosis resistance and propensity for necrosis in glioblastoma? A role for Bcl2L12 as a multifunctional cell death regulator.

    Science.gov (United States)

    Stegh, Alexander H; Chin, Lynda; Louis, David N; DePinho, Ronald A

    2008-09-15

    Glioblastoma (GBM) is the most common type of primary brain cancer and carries a dismal prognosis primarily due to the emergence of resistance towards extant radiation, conventional and targeted chemotherapies. Although GBM resists therapy-induced apoptosis, tumors show a seemingly paradoxical propensity for florid intratumoral necrogenesis. This necrosis manifests pathologically as microscopic foci or confluent expanses of necrotic tumor. While it is now well recognized that necrosis is an active cell death process and that apoptosis and necrosis death modalities are intertwined on multiple levels, the precise molecular mechanisms and genetic elements underlying these forms of cell death in GBM remain areas of active investigation. In recent oncogenomic studies, we identified a novel GBM oncoprotein, Bcl2-Like 12 (Bcl2L12), which is significantly expressed in the majority of primary GBM tumor specimens and distantly related to canonical Bcl-2 proteins. Due to its distinctive impact on cell death signaling, Bcl2L12 phenocopies pro-necrotic and anti-apoptotic propensities of high grade glioma: Mechanistically, we determined that unlike prototypic Bcl-2 family members, Bcl2L12 does not safeguard mitochondrial membrane integrity, but instead potently inhibits apoptosis at the level of post-mitochondrial effector caspase-3/7 activation. A combination of enforced expression, RNAi-mediated extinction, co-localization and protein interaction studies revealed that Bcl2L12 inhibits caspases 3 and 7 via distinct mechanisms. Direct physical interaction underlies Bcl2L12's inhibition of caspase-7 processing, whereas Bcl2L12-induced transcriptional upregulation of the small heat shock protein alpha B-crystallin is instrumental to neutralization of caspase-3 activation. Mirroring the cellular phenotype elicited by energy depletion, genetic or pharmacologic inhibition of post-mitochondrial apoptosis signaling molecules, Bcl2L12 promotes necrogenesis in glial cells in the context

  4. Epidermal cell death in frogs with chytridiomycosis

    Directory of Open Access Journals (Sweden)

    Laura A. Brannelly

    2017-02-01

    Full Text Available Background Amphibians are declining at an alarming rate, and one of the major causes of decline is the infectious disease chytridiomycosis. Parasitic fungal sporangia occur within epidermal cells causing epidermal disruption, but these changes have not been well characterised. Apoptosis (planned cell death can be a damaging response to the host but may alternatively be a mechanism of pathogen removal for some intracellular infections. Methods In this study we experimentally infected two endangered amphibian species Pseudophryne corroboree and Litoria verreauxii alpina with the causal agent of chytridiomycosis. We quantified cell death in the epidermis through two assays: terminal transferase-mediated dUTP nick end-labelling (TUNEL and caspase 3/7. Results Cell death was positively associated with infection load and morbidity of clinically infected animals. In infected amphibians, TUNEL positive cells were concentrated in epidermal layers, correlating to the localisation of infection within the skin. Caspase activity was stable and low in early infection, where pathogen loads were light but increasing. In animals that recovered from infection, caspase activity gradually returned to normal as the infection cleared. Whereas, in amphibians that did not recover, caspase activity increased dramatically when infection loads peaked. Discussion Increased cell death may be a pathology of the fungal parasite, likely contributing to loss of skin homeostatic functions, but it is also possible that apoptosis suppression may be used initially by the pathogen to help establish infection. Further research should explore the specific mechanisms of cell death and more specifically apoptosis regulation during fungal infection.

  5. MicroRNA-21 promotes cell proliferation and down-regulates the expression of programmed cell death 4 (PDCD4) in HeLa cervical carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Qing; Xu, Hui; Zhang, Qian-Qian; Zhou, Hui [Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-Sen University, Guangzhou 510275 (China); Qu, Liang-Hu, E-mail: lssqlh@mail.sysu.edu.cn [Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-Sen University, Guangzhou 510275 (China)

    2009-10-23

    MicroRNAs are involved in cancer-related processes. The microRNA-21(miR-21) has been identified as the only miRNA over-expressed in a wide variety of cancers, including cervical cancer. However, the function of miR-21 is unknown in cervical carcinomas. In this study, we found that the inhibition of miR-21 in HeLa cervical cancer cells caused profound suppression of cell proliferation, and up-regulated the expression of the tumor suppressor gene PDCD4. We also provide direct evidence that PDCD4-3'UTR is a functional target of miR-21 and that the 18 bp putative target site can function as the sole regulatory element in HeLa cells. These results suggest that miR-21 may play an oncogenic role in the cellular processes of cervical cancer and may serve as a target for effective therapies.

  6. Radiation-induced mitotic cell death and glioblastoma radioresistance: a new regulating pathway controlled by integrin-linked kinase, hypoxia-inducible factor 1 alpha and survivin in U87 cells.

    Science.gov (United States)

    Lanvin, Olivia; Monferran, Sylvie; Delmas, Caroline; Couderc, Bettina; Toulas, Christine; Cohen-Jonathan-Moyal, Elizabeth

    2013-09-01

    We have previously shown that integrin-linked kinase (ILK) regulates U87 glioblastoma cell radioresistance by modulating the main radiation-induced cell death mechanism in solid tumours, the mitotic cell death. To decipher the biological pathways involved in these mechanisms, we constructed a U87 glioblastoma cell model expressing an inducible shRNA directed against ILK (U87shILK). We then demonstrated that silencing ILK enhanced radiation-induced centrosome overduplication, leading to radiation-induced mitotic cell death. In this model, ionising radiations induce hypoxia-inducible factor 1 alpha (HIF-1α) stabilisation which is inhibited by silencing ILK. Moreover, silencing HIF-1α in U87 cells reduced the surviving fraction after 2 Gy irradiation by increasing cell sensitivity to radiation-induced mitotic cell death and centrosome amplification. Because it is known that HIF-1α controls survivin expression, we then looked at the ILK silencing effect on survivin expression. We show that survivin expression is decreased in U87shILK cells. Furthermore, treating U87 cells with the specific survivin suppressor YM155 significantly increased the percentage of giant multinucleated cells, centrosomal overduplication and thus U87 cell radiosensitivity. In consequence, we decipher here a new pathway of glioma radioresistance via the regulation of radiation-induced centrosome duplication and therefore mitotic cell death by ILK, HIF-1α and survivin. This work identifies new targets in glioblastoma with the intention of radiosensitising these highly radioresistant tumours. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Mitochondrion: A Common Organelle for Distinct Cell Deaths?

    Science.gov (United States)

    Wang, Z; Figueiredo-Pereira, C; Oudot, C; Vieira, H L A; Brenner, C

    2017-01-01

    Mitochondria are deeply involved in cell fate decisions via their multiple roles in metabolism, cell growth, and cell death. In healthy cells, these functions are highly regulated to provide sufficient energy for cell function, maintain cell homeostasis, and avoid undesirable cell death. This is achieved by an orchestrated cooperation of cellular and molecular mechanisms such as mitochondrial mass control (mitophagy vs biogenesis), oxidative phosphorylation, redox and calcium homeostasis, and the balance between pro- and antiapoptotic proteins. In the 1990s, mitochondria have been demonstrated to directly control some forms of regulated cell death as well indirectly through energetic metabolism modulation. However, a large body of literature revealed that distinct cell death modalities can coexist in vivo as well as that mitochondria can be dispensable for certain forms of cell death. Likewise, unexpected interconnections between cell death pathways can lead to an amplification of lethality, as well as a defeat of cell death resistance mechanisms. This revealed a complexity of the control of cell fate and a crucial need to reevaluate the role of mitochondria. Here, we will review the various cell death pathways such as apoptosis and mitochondrial permeability transition-driven necrosis and discuss how mitochondrial proteins and mitophagy regulate them. Finally, the role of mitochondrial proteins in the triggering of cell death and mitophagy in pathological models, such as cardiac and brain pathologies, will be highlighted. This may help to define efficient cytoprotective therapeutic strategies based on the targeting of mitochondria. © 2017 Elsevier Inc. All rights reserved.

  8. Constitutively active ErbB2 regulates cisplatin-induced cell death in breast cancer cells via pro- and antiapoptotic mechanisms

    DEFF Research Database (Denmark)

    Sigurðsson, Haraldur H; Olesen, Christina Wilkens; Dybboe, Rie

    2015-01-01

    UNLABELLED: Despite the frequent expression of N-terminally truncated ErbB2 (ΔNErbB2/p95HER2) in breast cancer and its association with Herceptin resistance and poor prognosis, it remains poorly understood how ΔNErbB2 affects chemotherapy-induced cell death. Previously it was shown that ΔNErbB2...

  9. [BNIP3 as an atypical representative of the Bcl-2 protein family. Part 1: BNIP3, a regulator of non-apoptotic programmed cell death].

    Science.gov (United States)

    Swoboda, Ewelina; Strzadała, Leon

    2009-09-10

    BNIP3 is classified as a member of the Bcl-2 protein family that regulates programmed cell death and of the BH3-only protein subfamily as it only contains one BH domain. However, the transmembrane domain of BNIP3 is involved in at least some of its pro-apoptotic functions. Although there are some similarities between BNIP3 and other BH3-only proteins, for example the ability to interact with anti-apoptotic Bcl-2 proteins and to induce cytochrome c release from mitochondria, BNIP3 is undoubtedly distinct in regard to its activity and regulatory mechanisms. Not only can BNIP3 activate apoptosis, but also, or perhaps first of all, it can activate necrosis-like cell death due to its direct interaction with the mitochondrial membrane. BNIP3 is also involved is autophagy, but its role in this process is not yet clearly understood. It is possible that the induction or stimulation of autophagy by this protein can simultaneously inhibit apoptosis, for example in cardiac myocytes. In some cells, BNIP3 is sequestered in the nucleus, where it also acts as an anti-apoptotic factor, namely as a repressor of AIF transcription. This activity may enable tumor cells to achieve resistance to chemotherapeutics. Understanding BNIP3 functions and regulatory mechanisms can point to new molecular targets in the treatment of cancer and ischemic heart or brain diseases.

  10. BNIP3 as an atypical representative of the Bcl-2 protein family. Part 1: BNIP3, a regulator of non-apoptotic programmed cell death

    Directory of Open Access Journals (Sweden)

    Ewelina Swoboda

    2009-09-01

    Full Text Available BNIP3 is classified as a member of the Bcl-2 protein family that regulates programmed cell death and of the BH3-only protein subfamily as it only contains one BH domain. However, the transmembrane domain of BNIP3 is involved in at least some of its pro-apoptotic functions. Although there are some similarities between BNIP3 and other BH3-only proteins, for example the ability to interact with anti-apoptotic Bcl-2 proteins and to induce cytochrome c release from mitochondria, BNIP3 is undoubtedly distinct in regard to its activity and regulatory mechanisms. Not only can BNIP3 activate apoptosis, but also, or perhaps first of all, it can activate necrosis-like cell death due to its direct interaction with the mitochondrial membrane. BNIP3 is also involved is autophagy, but its role in this process is not yet clearly understood. It is possible that the induction or stimulation of autophagy by this protein can simultaneously inhibit apoptosis, for example in cardiac myocytes. In some cells, BNIP3 is sequestered in the nucleus, where it also acts as an anti-apoptotic factor, namely as a repressor of AIF transcription. This activity may enable tumor cells to achieve resistance to chemotherapeutics. Understanding BNIP3 functions and regulatory mechanisms can point to new molecular targets in the treatment of cancer and ischemic heart or brain diseases.

  11. Reactive oxygen species and extracellular signal-regulated kinase 1/2 mediate hexachlorobenzene-induced cell death in FRTL-5 rat throyd cells

    OpenAIRE

    Chiappini, Florencia Ana; Pontillo, Carolina Andrea; Randi, Andrea Silvana; Alvarez, Laura; Kleiman, Diana Leonor

    2015-01-01

    Hexachlorobenzene (HCB) is an organochlorine pesticide widely distributed in the environment. We have previously shown that chronic HCB exposure triggers apoptosis in rat thyroid follicular cells. This study was carried out to investigate the molecular mechanism by which the pesticide causes apoptosis in FRTL-5 rat thyroid cells exposed to HCB (0.005, 0.05, 0.5, and 5μM) for 2, 6, 8, 24, and 48 h. HCB treatment lowered cell viability and induced apoptotic cell death in a dose- and time-depend...

  12. Lace plant ethylene receptors, AmERS1a and AmERS1c, regulate ethylene-induced programmed cell death during leaf morphogenesis.

    Science.gov (United States)

    Rantong, Gaolathe; Evans, Rodger; Gunawardena, Arunika H L A N

    2015-10-01

    The lace plant, Aponogeton madagascariensis, is an aquatic monocot that forms perforations in its leaves as part of normal leaf development. Perforation formation occurs through developmentally regulated programmed cell death (PCD). The molecular basis of PCD regulation in the lace plant is unknown, however ethylene has been shown to play a significant role. In this study, we examined the role of ethylene receptors during perforation formation. We isolated three lace plant ethylene receptors AmERS1a, AmERS1b and AmERS1c. Using quantitative PCR, we examined their transcript levels at seven stages of leaf development. Through laser-capture microscopy, transcript levels were also determined in cells undergoing PCD and cells not undergoing PCD (NPCD cells). AmERS1a transcript levels were significantly lower in window stage leaves (in which perforation formation and PCD are occurring) as compared to all other leaf developmental stages. AmERS1a and AmERS1c (the most abundant among the three receptors) had the highest transcript levels in mature stage leaves, where PCD is not occurring. Their transcript levels decreased significantly during senescence-associated PCD. AmERS1c had significantly higher transcript levels in NPCD compared to PCD cells. Despite being significantly low in window stage leaves, AmERS1a transcripts were not differentially expressed between PCD and NPCD cells. The results suggested that ethylene receptors negatively regulate ethylene-controlled PCD in the lace plant. A combination of ethylene and receptor levels determines cell fate during perforation formation and leaf senescence. A new model for ethylene emission and receptor expression during lace plant perforation formation and senescence is proposed.

  13. The deaths of a cell: how language and metaphor influence the science of cell death.

    Science.gov (United States)

    Reynolds, Andrew S

    2014-12-01

    Multicellular development and tissue maintenance involve the regular elimination of damaged and healthy cells. The science of this genetically regulated cell death is particularly rich in metaphors: 'programmed cell death' or 'cell suicide' is considered an 'altruistic' act on the part of a cell for the benefit of the organism as a whole. It is also considered a form of 'social control' exerted by the body/organism over its component cells. This paper analyzes the various functions of these metaphors and critical discussion about them within the scientific community. Bodies such as the Nomenclature Committee on Cell Death (NCCD) have been charged with bringing order to the language of cell death to facilitate scientific progress. While the NCCD recommends adopting more objective biochemical terminology to describe the mechanisms of cell death, the metaphors in question retain an important function by highlighting the broader context within which cell death occurs. Scientific metaphors act as conceptual 'tools' which fulfill various roles, from highlighting a phenomenon as of particular interest, situating it in a particular context, or suggesting explanatory causal mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. MAPK/JNK1 activation protects cells against cadmium-induced autophagic cell death via differential regulation of catalase and heme oxygenase-1 in oral cancer cells.

    Science.gov (United States)

    So, Keum-Young; Kim, Sang-Hun; Jung, Ki-Tae; Lee, Hyun-Young; Oh, Seon-Hee

    2017-10-01

    Antioxidant enzymes are related to oral diseases. We investigated the roles of heme oxygenase-1 (HO-1) and catalase in cadmium (Cd)-induced oxidative stress and the underlying molecular mechanism in oral cancer cells. Exposing YD8 cells to Cd reduced the expression levels of catalase and superoxide dismutase 1/2 and induced the expression of HO-1 as well as autophagy and apoptosis, which were reversed by N-acetyl-l-cysteine (NAC). Cd-exposed YD10B cells exhibited milder effects than YD8 cells, indicating that Cd sensitivity is associated with antioxidant enzymes and autophagy. Autophagy inhibition via pharmacologic and genetic modulations enhanced Cd-induced HO-1 expression, caspase-3 cleavage, and the production of reactive oxygen species (ROS). Ho-1 knockdown increased autophagy and apoptosis. Hemin treatment partially suppressed Cd-induced ROS production and apoptosis, but enhanced autophagy and CHOP expression, indicating that autophagy induction is associated with cellular stress. Catalase inhibition by pharmacological and genetic modulations increased Cd-induced ROS production, autophagy, and apoptosis, but suppressed HO-1, indicating that catalase is required for HO-1 induction. p38 inhibition upregulated Cd-induced phospho-JNK and catalase, but suppressed HO-1, autophagy, apoptosis. JNK suppression exhibited contrary results, enhancing the expression of phospho-p38. Co-suppression of p38 and JNK1 failed to upregulate catalase and procaspase-3, which were upregulated by JNK1 overexpression. Overall, the balance between the responses of p38 and JNK activation to Cd appears to have an important role in maintaining cellular homeostasis via the regulation of antioxidant enzymes and autophagy induction. In addition, the upregulation of catalase by JNK1 activation can play a critical role in cell protection against Cd-induced oxidative stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Protein Kinase Pathways That Regulate Neuronal Survival and Death

    Science.gov (United States)

    2004-08-01

    intracellular T. gondii replication. International Congress on Toxoplasmosis . Freising, Germany, 2001. 13. Linseman, DA, T Laessig, MK Meintzer, M...University of Colo- role in the regulation of metabolic pathways as well as preven- rado Cancer Center core facility. tion of cell death by insulin and

  16. The miR9863 family regulates distinct Mla alleles in barley to attenuate NLR receptor-triggered disease resistance and cell-death signaling.

    Directory of Open Access Journals (Sweden)

    Jie Liu

    2014-12-01

    Full Text Available Barley (Hordeum vulgare L. Mla alleles encode coiled-coil (CC, nucleotide binding, leucine-rich repeat (NB-LRR receptors that trigger isolate-specific immune responses against the powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh. How Mla or NB-LRR genes in grass species are regulated at post-transcriptional level is not clear. The microRNA family, miR9863, comprises four members that differentially regulate distinct Mla alleles in barley. We show that miR9863 members guide the cleavage of Mla1 transcripts in barley, and block or reduce the accumulation of MLA1 protein in the heterologous Nicotiana benthamiana expression system. Regulation specificity is determined by variation in a unique single-nucleotide-polymorphism (SNP in mature miR9863 family members and two SNPs in the Mla miR9863-binding site that separates these alleles into three groups. Further, we demonstrate that 22-nt miR9863s trigger the biogenesis of 21-nt phased siRNAs (phasiRNAs and together these sRNAs form a feed-forward regulation network for repressing the expression of group I Mla alleles. Overexpression of miR9863 members specifically attenuates MLA1, but not MLA10-triggered disease resistance and cell-death signaling. We propose a key role of the miR9863 family in dampening immune response signaling triggered by a group of MLA immune receptors in barley.

  17. The miR9863 family regulates distinct Mla alleles in barley to attenuate NLR receptor-triggered disease resistance and cell-death signaling.

    Science.gov (United States)

    Liu, Jie; Cheng, Xiliu; Liu, Da; Xu, Weihui; Wise, Roger; Shen, Qian-Hua

    2014-12-01

    Barley (Hordeum vulgare L.) Mla alleles encode coiled-coil (CC), nucleotide binding, leucine-rich repeat (NB-LRR) receptors that trigger isolate-specific immune responses against the powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh). How Mla or NB-LRR genes in grass species are regulated at post-transcriptional level is not clear. The microRNA family, miR9863, comprises four members that differentially regulate distinct Mla alleles in barley. We show that miR9863 members guide the cleavage of Mla1 transcripts in barley, and block or reduce the accumulation of MLA1 protein in the heterologous Nicotiana benthamiana expression system. Regulation specificity is determined by variation in a unique single-nucleotide-polymorphism (SNP) in mature miR9863 family members and two SNPs in the Mla miR9863-binding site that separates these alleles into three groups. Further, we demonstrate that 22-nt miR9863s trigger the biogenesis of 21-nt phased siRNAs (phasiRNAs) and together these sRNAs form a feed-forward regulation network for repressing the expression of group I Mla alleles. Overexpression of miR9863 members specifically attenuates MLA1, but not MLA10-triggered disease resistance and cell-death signaling. We propose a key role of the miR9863 family in dampening immune response signaling triggered by a group of MLA immune receptors in barley.

  18. The miR9863 Family Regulates Distinct Mla Alleles in Barley to Attenuate NLR Receptor-Triggered Disease Resistance and Cell-Death Signaling

    Science.gov (United States)

    Liu, Jie; Cheng, Xiliu; Liu, Da; Xu, Weihui; Wise, Roger; Shen, Qian-Hua

    2014-01-01

    Barley (Hordeum vulgare L.) Mla alleles encode coiled-coil (CC), nucleotide binding, leucine-rich repeat (NB-LRR) receptors that trigger isolate-specific immune responses against the powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh). How Mla or NB-LRR genes in grass species are regulated at post-transcriptional level is not clear. The microRNA family, miR9863, comprises four members that differentially regulate distinct Mla alleles in barley. We show that miR9863 members guide the cleavage of Mla1 transcripts in barley, and block or reduce the accumulation of MLA1 protein in the heterologous Nicotiana benthamiana expression system. Regulation specificity is determined by variation in a unique single-nucleotide-polymorphism (SNP) in mature miR9863 family members and two SNPs in the Mla miR9863-binding site that separates these alleles into three groups. Further, we demonstrate that 22-nt miR9863s trigger the biogenesis of 21-nt phased siRNAs (phasiRNAs) and together these sRNAs form a feed-forward regulation network for repressing the expression of group I Mla alleles. Overexpression of miR9863 members specifically attenuates MLA1, but not MLA10-triggered disease resistance and cell-death signaling. We propose a key role of the miR9863 family in dampening immune response signaling triggered by a group of MLA immune receptors in barley. PMID:25502438

  19. Plasma membrane changes during programmed cell deaths.

    Science.gov (United States)

    Zhang, Yingying; Chen, Xin; Gueydan, Cyril; Han, Jiahuai

    2018-01-01

    Ruptured and intact plasma membranes are classically considered as hallmarks of necrotic and apoptotic cell death, respectively. As such, apoptosis is usually considered a non-inflammatory process while necrosis triggers inflammation. Recent studies on necroptosis and pyroptosis, two types of programmed necrosis, revealed that plasma membrane rupture is mediated by MLKL channels during necroptosis but depends on non-selective gasdermin D (GSDMD) pores during pyroptosis. Importantly, the morphology of dying cells executed by MLKL channels can be distinguished from that executed by GSDMD pores. Interestingly, it was found recently that secondary necrosis of apoptotic cells, a previously believed non-regulated form of cell lysis that occurs after apoptosis, can be programmed and executed by plasma membrane pore formation like that of pyroptosis. In addition, pyroptosis is associated with pyroptotic bodies, which have some similarities to apoptotic bodies. Therefore, different cell death programs induce distinctive reshuffling processes of the plasma membrane. Given the fact that the nature of released intracellular contents plays a crucial role in dying/dead cell-induced immunogenicity, not only membrane rupture or integrity but also the nature of plasma membrane breakdown would determine the fate of a cell as well as its ability to elicit an immune response. In this review, we will discuss recent advances in the field of apoptosis, necroptosis and pyroptosis, with an emphasis on the mechanisms underlying plasma membrane changes observed on dying cells and their implication in cell death-elicited immunogenicity.

  20. Oxylipin biosynthesis genes positively regulate programmed cell death during compatible infections with the synergistic pair potato virus X-potato virus Y and Tomato spotted wilt virus.

    Science.gov (United States)

    García-Marcos, Alberto; Pacheco, Remedios; Manzano, Aranzazu; Aguilar, Emmanuel; Tenllado, Francisco

    2013-05-01

    One of the most severe symptoms caused by compatible plant-virus interactions is systemic necrosis, which shares common attributes with the hypersensitive response to incompatible pathogens. Although several studies have identified viral symptom determinants responsible for systemic necrosis, mechanistic models of how they contribute to necrosis in infected plants remain scarce. Here, we examined the involvement of different branches of the oxylipin biosynthesis pathway in the systemic necrosis response caused either by the synergistic interaction of Potato virus X with Potato virus Y (PVX-PVY) or by Tomato spotted wilt virus (TSWV) in Nicotiana benthamiana. Silencing either 9-lipoxygenase (LOX), 13-LOX, or α-dioxygenase-1 (α-DOX-1) attenuated the programmed cell death (PCD)-associated symptoms caused by infection with either PVX-PVY or TSWV. In contrast, silencing of the jasmonic acid perception gene, COI1 (Coronatine insensitive 1), expedited cell death during infection with compatible viruses. This correlated with an enhanced expression of oxylipin biosynthesis genes and dioxygenase activity in PVX-PVY-infected plants. Moreover, the Arabidopsis thaliana double lox1 α-dox-1 mutant became less susceptible to TSWV infection. We conclude that oxylipin metabolism is a critical component that positively regulates the process of PCD during compatible plant-virus interactions but does not play a role in restraining virus accumulation in planta.

  1. BID links ferroptosis to mitochondrial cell death pathways

    NARCIS (Netherlands)

    Neitemeier, Sandra; Jelinek, Anja; Laino, Vincenzo; Hoffmann, Lena; Eisenbach, Ina; Eying, Roman; Ganjam, Goutham K; Dolga, Amalia M; Oppermann, Sina; Culmsee, Carsten

    2017-01-01

    Ferroptosis has been defined as an oxidative and iron-dependent pathway of regulated cell death that is distinct from caspase-dependent apoptosis and established pathways of death receptor-mediated regulated necrosis. While emerging evidence linked features of ferroptosis induced e.g. by

  2. Chloroacetic acid induced neuronal cells death through oxidative stress-mediated p38-MAPK activation pathway regulated mitochondria-dependent apoptotic signals.

    Science.gov (United States)

    Chen, Chun-Hung; Chen, Sz-Jie; Su, Chin-Chuan; Yen, Cheng-Chieh; Tseng, To-Jung; Jinn, Tzyy-Rong; Tang, Feng-Cheng; Chen, Kuo-Liang; Su, Yi-Chang; Lee, kuan-I; Hung, Dong-Zong; Huang, Chun-Fa

    2013-01-07

    Chloroacetic acid (CA), a toxic chlorinated analog of acetic acid, is widely used in chemical industries as an herbicide, detergent, and disinfectant, and chemical intermediates that are formed during the synthesis of various products. In addition, CA has been found as a by-product of chlorination disinfection of drinking water. However, there is little known about neurotoxic injuries of CA on the mammalian, the toxic effects and molecular mechanisms of CA-induced neuronal cell injury are mostly unknown. In this study, we examined the cytotoxicity of CA on cultured Neuro-2a cells and investigated the possible mechanisms of CA-induced neurotoxicity. Treatment of Neuro-2a cells with CA significantly reduced the number of viable cells (in a dose-dependent manner with a range from 0.1 to 3mM), increased the generation of ROS, and reduced the intracellular levels of glutathione depletion. CA also increased the number of sub-G1 hypodiploid cells; increased mitochondrial dysfunction (loss of MMP, cytochrome c release, and accompanied by Bcl-2 and Mcl-1 down-regulation and Bax up-regulation), and activated the caspase cascades activations, which displayed features of mitochondria-dependent apoptosis pathway. These CA-induced apoptosis-related signals were markedly prevented by the antioxidant N-acetylcysteine (NAC). Moreover, CA activated the JNK and p38-MAPK pathways, but did not that ERK1/2 pathway, in treated Neuro-2a cells. Pretreatment with NAC and specific p38-MAPK inhibitor (SB203580), but not JNK inhibitor (SP600125) effectively abrogated the phosphorylation of p38-MAPK and attenuated the apoptotic signals (including: decrease in cytotoxicity, caspase-3/-7 activation, the cytosolic cytochrome c release, and the reversed alteration of Bcl-2 and Bax mRNA) in CA-treated Neuro-2a cells. Taken together, these data suggest that oxidative stress-induced p38-MAPK activated pathway-regulated mitochondria-dependent apoptosis plays an important role in CA-caused neuronal cell

  3. Lipid peroxidation in cell death.

    Science.gov (United States)

    Gaschler, Michael M; Stockwell, Brent R

    2017-01-15

    Disruption of redox homeostasis is a key phenotype of many pathological conditions. Though multiple oxidizing compounds such as hydrogen peroxide are widely recognized as mediators and inducers of oxidative stress, increasingly, attention is focused on the role of lipid hydroperoxides as critical mediators of death and disease. As the main component of cellular membranes, lipids have an indispensible role in maintaining the structural integrity of cells. Excessive oxidation of lipids alters the physical properties of cellular membranes and can cause covalent modification of proteins and nucleic acids. This review discusses the synthesis, toxicity, degradation, and detection of lipid peroxides in biological systems. Additionally, the role of lipid peroxidation is highlighted in cell death and disease, and strategies to control the accumulation of lipid peroxides are discussed. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  4. Sphingolipid metabolism and programmed cell death in tomato

    NARCIS (Netherlands)

    Spassieva, Stefanka Diankova

    2003-01-01

    Programmed cell death is genetically determined. When the regulation of the process is disrupted it can have severe or lethal consequences for the organism. In mammals, cancer and neurodegenerative diseases are associated with abnormalities in programmed cell death. Development of an animal embryo

  5. Eurycomanone and Eurycomanol from Eurycoma longifolia Jack as Regulators of Signaling Pathways Involved in Proliferation, Cell Death and Inflammation

    Directory of Open Access Journals (Sweden)

    Shéhérazade Hajjouli

    2014-09-01

    Full Text Available Eurycomanone and eurycomanol are two quassinoids from the roots of Eurycoma longifolia Jack. The aim of this study was to assess the bioactivity of these compounds in Jurkat and K562 human leukemia cell models compared to peripheral blood mononuclear cells from healthy donors. Both eurycomanone and eurycomanol inhibited Jurkat and K562 cell viability and proliferation without affecting healthy cells. Interestingly, eurycomanone inhibited NF-κB signaling through inhibition of IκBα phosphorylation and upstream mitogen activated protein kinase (MAPK signaling, but not eurycomanol. In conclusion, both quassinoids present differential toxicity towards leukemia cells, and the presence of the α,β-unsaturated ketone in eurycomanone could be prerequisite for the NF-κB inhibition.

  6. Cell Death in C. elegans Development.

    Science.gov (United States)

    Malin, Jennifer Zuckerman; Shaham, Shai

    2015-01-01

    Cell death is a common and important feature of animal development, and cell death defects underlie many human disease states. The nematode Caenorhabditis elegans has proven fertile ground for uncovering molecular and cellular processes controlling programmed cell death. A core pathway consisting of the conserved proteins EGL-1/BH3-only, CED-9/BCL2, CED-4/APAF1, and CED-3/caspase promotes most cell death in the nematode, and a conserved set of proteins ensures the engulfment and degradation of dying cells. Multiple regulatory pathways control cell death onset in C. elegans, and many reveal similarities with tumor formation pathways in mammals, supporting the idea that cell death plays key roles in malignant progression. Nonetheless, a number of observations suggest that our understanding of developmental cell death in C. elegans is incomplete. The interaction between dying and engulfing cells seems to be more complex than originally appreciated, and it appears that key aspects of cell death initiation are not fully understood. It has also become apparent that the conserved apoptotic pathway is dispensable for the demise of the C. elegans linker cell, leading to the discovery of a previously unexplored gene program promoting cell death. Here, we review studies that formed the foundation of cell death research in C. elegans and describe new observations that expand, and in some cases remodel, this edifice. We raise the possibility that, in some cells, more than one death program may be needed to ensure cell death fidelity. © 2015 Elsevier Inc. All rights reserved.

  7. [Phenolic antioxidant TS-13 regulating ARE-dependent genes induces tumor cell death by mitochondria-dependent pathway].

    Science.gov (United States)

    Martinovich, G G; Martinovich, I V; Zenkov, N K; Men'shikova, E B; Kandalintseva, N V; Cherenkevich, S N

    2015-01-01

    Effects of water-soluble phenolic antioxidant sodium 3-(3'-tret-butyl-4'-hydroxyphenyl)-propyl thiosulfonate (TS-13), potassium 3,5-dimethyl-4-hydroxybenzyl thioetanoate (BEP-11-K) and potassium 3-(3',5'-ditretbutyl-4'-hydroxyphenyl)-propionate (potassium phenosan) on tumor cells proliferative activity and the role of redox-dependent and calcium-dependent signaling mechanisms in realization of tumor cell response to the antioxidant action were studied. Potassium phenosan and BEP-11-K were found to stimulate proliferation and ARE-inducing phenolic antioxidant TS-13 was found to inhibit tumor cell growth in culture. The tumor cell growth rate depended on the rate of intracellular reactive oxygen species production and was decreased by apocynin (a NADPH-oxidase inhibitor) and antimycin A (an ubiquinol-cytochrome c oxidoreductase inhibitor). TS-13 action on tumor cells was accompanied by a transient increase in intracellular reactive oxygen species production and the intracellular calcium concentration, whereas cell incubation with potassium phenosan and BEP-11-K did not influence the reactive oxygen species level and intracellular calcium ions. Cyclosporine A blocked the inhibitory effect of TS-13. Thus, it can be reasonably speculated that phenolic antioxidant TS-13 starts mitochondria-dependent apoptosis in tumor cells by the opening of permeability transition pores.

  8. Regulation of beta cell replication

    DEFF Research Database (Denmark)

    Lee, Ying C; Nielsen, Jens Høiriis

    2008-01-01

    Beta cell mass, at any given time, is governed by cell differentiation, neogenesis, increased or decreased cell size (cell hypertrophy or atrophy), cell death (apoptosis), and beta cell proliferation. Nutrients, hormones and growth factors coupled with their signalling intermediates have been...... suggested to play a role in beta cell mass regulation. In addition, genetic mouse model studies have indicated that cyclins and cyclin-dependent kinases that determine cell cycle progression are involved in beta cell replication, and more recently, menin in association with cyclin-dependent kinase...... inhibitors has been demonstrated to be important in beta cell growth. In this review, we consider and highlight some aspects of cell cycle regulation in relation to beta cell replication. The role of cell cycle regulation in beta cell replication is mostly from studies in rodent models, but whether...

  9. Quercetin up-regulates mitochondrial complex-I activity to protect against programmed cell death in rotenone model of Parkinson's disease in rats.

    Science.gov (United States)

    Karuppagounder, S S; Madathil, S K; Pandey, M; Haobam, R; Rajamma, U; Mohanakumar, K P

    2013-04-16

    We tested quercetin, a dietary bioflavonoid with potent free radical scavenging action and antioxidant activity, for its neuroprotective effects in rotenone-induced hemi-parkinsonian rats. Rats were infused unilaterally with rotenone into the substantia nigra, and quercetin (25-75mg/kg, i.p.) was administered at 12-h intervals for 4days, and analyzed on the 5th day. Amphetamine- or apomorphine-induced unilateral rotations were significantly reduced in quercetin-treated rats, when analyzed on 14th or 16th day post-surgery, respectively. Quercetin possessed potent hydroxyl radical scavenging action in a cells-free, Fenton-like reaction in test tubes, and in isolated mitochondria when measured by salicylate hydroxylation method. We observed dose-dependent attenuation of the rotenone-induced loss in striatal dopamine, and nigral oxidized and reduced glutathione, as well as the increases in endogenous antioxidant enzymes (catalase and superoxide dismutase) activities supporting the notion that quercetin-effect is mediated via its powerful hydroxyl radicals-scavenging and antioxidant actions. Quercetin's dose-dependent ability to up-regulate mitochondrial complex-I activity, as evidenced by NADH-oxidation, and as seen in blue native-polyacrylamide gel electrophoresis (PAGE) staining in both the contra- and ipsi-lateral nigra suggests the containment of reactive oxygen production at the mitochondrial level. Rotenone-induced induction of NADH-diaphorase activity in the nigral neurons, and its attenuation by quercetin pointed to the possible involvement of nitric oxide too. Reversal of neuronal death induced by rotenone as observed by increased tyrosine hydroxylase-positive cells and decreased TdT-mediated dUTP nick end-labeling (TUNEL) staining in the substantia nigra confirmed the potential of quercetin to revamp dopaminergic cells following oxidative stress mediated programmed cell death and neuronal demise. The present study strongly implicates quercetin's potential

  10. Song Bu Li Decoction, a Traditional Uyghur Medicine, Protects Cell Death by Regulation of Oxidative Stress and Differentiation in Cultured PC12 Cells

    Directory of Open Access Journals (Sweden)

    Maitinuer Maiwulanjiang

    2013-01-01

    Full Text Available Song Bu Li decoction (SBL is a traditional Uyghur medicinal herbal preparation, containing Nardostachyos Radix et Rhizoma. Recently, SBL is being used to treat neurological disorders (insomnia and neurasthenia and heart disorders (arrhythmia and palpitation. Although this herbal extract has been used for many years, there is no scientific basis about its effectiveness. Here, we aimed to evaluate the protective and differentiating activities of SBL in cultured PC12 cells. The pretreatment of SBL protected the cell against tBHP-induced cell death in a dose-dependent manner. In parallel, SBL suppressed intracellular reactive oxygen species (ROS formation. The transcriptional activity of antioxidant response element (ARE, as well as the key antioxidative stress proteins, was induced in dose-dependent manner by SBL in the cultures. In cultured PC12 cells, the expression of neurofilament, a protein marker for neuronal differentiation, was markedly induced by applied herbal extract. Moreover, the nerve growth factor- (NGF- induced neurite outgrowth in cultured PC12 cells was significantly potentiated by the cotreatment of SBL. In accord, the expression of neurofilament was increased in the treatment of SBL. These results therefore suggested a possible role of SBL by its effect on neuron differentiation and protection against oxidative stress.

  11. Quinazoline-based tricyclic compounds that regulate programmed cell death, induce neuronal differentiation, and are curative in animal models for excitotoxicity and hereditary brain disease

    OpenAIRE

    Vainshtein, A.; Veenman, L; Shterenberg, A; Singh, S; Masarwa, A; Dutta, B.; Island, B; Tsoglin, E; Levin, E.; Leschiner, S; Maniv, I; Pe?er, L; Otradnov, I; Zubedat, S; Aga-Mizrachi, S

    2015-01-01

    Expanding on a quinazoline scaffold, we developed tricyclic compounds with biological activity. These compounds bind to the 18?kDa translocator protein (TSPO) and protect U118MG (glioblastoma cell line of glial origin) cells from glutamate-induced cell death. Fascinating, they can induce neuronal differentiation of PC12 cells (cell line of pheochromocytoma origin with neuronal characteristics) known to display neuronal characteristics, including outgrowth of neurites, tubulin expression, and ...

  12. COX-2 regulation and TUNEL-positive cell death differ between genders in the secondary inflammatory response following experimental penetrating focal brain injury in rats.

    Science.gov (United States)

    Günther, Mattias; Plantman, Stefan; Davidsson, Johan; Angéria, Maria; Mathiesen, Tiit; Risling, Mårten

    2015-04-01

    Traumatic brain injury is followed by secondary neuronal degeneration, largely dependent on an inflammatory response. This response is probably gender specific, since females are better protected than males in experimental models. The reasons are not fully known. We examined aspects of the inflammatory response following experimental TBI in male and female rats to explore possible gender differences at 24 h and 72 h after trauma, times of peak histological inflammation and neuronal degeneration. A penetrating brain injury model was used to produce penetrating focal TBI in 20 Sprague-Dawley rats, 5 males and 5 females for each time point. After 24 and 72 h the brains were removed and subjected to in situ hybridization and immunohistochemical analyses for COX-2, iNOS, osteopontin, glial fibrillary acidic protein, 3-nitrotyrosine, TUNEL and Fluoro-Jade. COX-2 mRNA and protein levels were increased in the perilesional area compared to the uninjured contralateral side and significantly higher in males at 24 h and 72 h (p genders. COX-2 regulation differed between genders after TBI. The increased COX-2 expression in male rats correlated with increased apoptotic cell death detected by increased TUNEL staining at 24 h, but not with neuronal necrosis measured by Flouro-Jade. Astrogliosis and microgliosis did not differ, confirming a comparable level of trauma. The gender-specific trait of the secondary inflammatory response may be connected to prostaglandin regulation, which may partially explain gender variances in outcome after TBI.

  13. Polycation-mediated integrated cell death processes

    DEFF Research Database (Denmark)

    Parhamifar, Ladan; Andersen, Helene; Wu, Linping

    2014-01-01

    standard. PEIs are highly efficient transfectants, but depending on their architecture and size they induce cytotoxicity through different modes of cell death pathways. Here, we briefly review dynamic and integrated cell death processes and pathways, and discuss considerations in cell death assay design...

  14. Physiology of cell volume regulation in vertebrates

    DEFF Research Database (Denmark)

    Hoffmann, Else K; Lambert, Ian H; Pedersen, Stine F

    2009-01-01

    organisms. Importantly, cell volume impacts on a wide array of physiological processes, including transepithelial transport; cell migration, proliferation, and death; and changes in cell volume function as specific signals regulating these processes. A discussion of this issue concludes the review....

  15. Pathogen-mediated proteolysis of the cell death regulator RIPK1 and the host defense modulator RIPK2 in human aortic endothelial cells.

    Directory of Open Access Journals (Sweden)

    Andrés G Madrigal

    Full Text Available Porphyromonas gingivalis is the primary etiologic agent of periodontal disease that is associated with other human chronic inflammatory diseases, including atherosclerosis. The ability of P. gingivalis to invade and persist within human aortic endothelial cells (HAEC has been postulated to contribute to a low to moderate chronic state of inflammation, although how this is specifically achieved has not been well defined. In this study, we demonstrate that P. gingivalis infection of HAEC resulted in the rapid cleavage of receptor interacting protein 1 (RIPK1, a mediator of tumor necrosis factor (TNF receptor-1 (TNF-R1-induced cell activation or death, and RIPK2, a key mediator of both innate immune signaling and adaptive immunity. The cleavage of RIPK1 or RIPK2 was not observed in cells treated with apoptotic stimuli, or cells stimulated with agonists to TNF-R1, nucleotide oligomerization domain receptor 1(NOD1, NOD2, Toll-like receptor 2 (TLR2 or TLR4. P. gingivalis-induced cleavage of RIPK1 and RIPK2 was inhibited in the presence of a lysine-specific gingipain (Kgp inhibitor. RIPK1 and RIPK2 cleavage was not observed in HAEC treated with an isogenic mutant deficient in the lysine-specific gingipain, confirming a role for Kgp in the cleavage of RIPK1 and RIPK2. Similar proteolysis of poly (ADP-ribose polymerase (PARP was observed. We also demonstrated direct proteolysis of RIPK2 by P. gingivalis in a cell-free system which was abrogated in the presence of a Kgp-specific protease inhibitor. Our studies thus reveal an important role for pathogen-mediated modification of cellular kinases as a potential strategy for bacterial persistence within target host cells, which is associated with low-grade chronic inflammation, a hallmark of pathogen-mediated chronic inflammatory disorders.

  16. The nuclear guanine nucleotide exchange factors Ect2 and Net1 regulate RhoB-mediated cell death after DNA damage.

    Directory of Open Access Journals (Sweden)

    Melissa C Srougi

    2011-02-01

    Full Text Available Commonly used antitumor treatments, including radiation and chemotherapy, function by damaging the DNA of rapidly proliferating cells. However, resistance to these agents is a predominant clinical problem. A member of the Rho family of small GTPases, RhoB has been shown to be integral in mediating cell death after ionizing radiation (IR or other DNA damaging agents in Ras-transformed cell lines. In addition, RhoB protein expression increases after genotoxic stress, and loss of RhoB expression causes radio- and chemotherapeutic resistance. However, the signaling pathways that govern RhoB-induced cell death after DNA damage remain enigmatic. Here, we show that RhoB activity increases in human breast and cervical cancer cell lines after treatment with DNA damaging agents. Furthermore, RhoB activity is necessary for DNA damage-induced cell death, as the stable loss of RhoB protein expression using shRNA partially protects cells and prevents the phosphorylation of c-Jun N-terminal kinases (JNKs and the induction of the pro-apoptotic protein Bim after IR. The increase in RhoB activity after genotoxic stress is associated with increased activity of the nuclear guanine nucleotide exchange factors (GEFs, Ect2 and Net1, but not the cytoplasmic GEFs p115 RhoGEF or Vav2. Importantly, loss of Ect2 and Net1 via siRNA-mediated protein knock-down inhibited IR-induced increases in RhoB activity, reduced apoptotic signaling events, and protected cells from IR-induced cell death. Collectively, these data suggest a mechanism involving the nuclear GEFs Ect2 and Net1 for activating RhoB after genotoxic stress, thereby facilitating cell death after treatment with DNA damaging agents.

  17. Hydrogen Peroxide-induced Cell Death in Arabidopsis : Transcriptional and Mutant Analysis Reveals a Role of an Oxoglutarate-dependent Dioxygenase Gene in the Cell Death Process

    NARCIS (Netherlands)

    Gechev, Tsanko S.; Minkov, Ivan N.; Hille, Jacques

    2005-01-01

    Hydrogen peroxide is a major regulator of plant programmed cell death (PCD) but little is known about the downstream genes from the H2O2-signaling network that mediate the cell death. To address this question, a novel system for studying H2O2-induced programmed cell death in Arabidopsis thaliana was

  18. The RhoGAP SPIN6 associates with SPL11 and OsRac1 and negatively regulates programmed cell death and innate immunity in rice.

    Directory of Open Access Journals (Sweden)

    Jinling Liu

    2015-02-01

    Full Text Available The ubiquitin proteasome system in plants plays important roles in plant-microbe interactions and in immune responses to pathogens. We previously demonstrated that the rice U-box E3 ligase SPL11 and its Arabidopsis ortholog PUB13 negatively regulate programmed cell death (PCD and defense response. However, the components involved in the SPL11/PUB13-mediated PCD and immune signaling pathway remain unknown. In this study, we report that SPL11-interacting Protein 6 (SPIN6 is a Rho GTPase-activating protein (RhoGAP that interacts with SPL11 in vitro and in vivo. SPL11 ubiquitinates SPIN6 in vitro and degrades SPIN6 in vivo via the 26S proteasome-dependent pathway. Both RNAi silencing in transgenic rice and knockout of Spin6 in a T-DNA insertion mutant lead to PCD and increased resistance to the rice blast pathogen Magnaporthe oryzae and the bacterial blight pathogen Xanthomonas oryzae pv. oryzae. The levels of reactive oxygen species and defense-related gene expression are significantly elevated in both the Spin6 RNAi and mutant plants. Strikingly, SPIN6 interacts with the small GTPase OsRac1, catalyze the GTP-bound OsRac1 into the GDP-bound state in vitro and has GAP activity towards OsRac1 in rice cells. Together, our results demonstrate that the RhoGAP SPIN6 acts as a linkage between a U-box E3 ligase-mediated ubiquitination pathway and a small GTPase-associated defensome system for plant immunity.

  19. Activation of apoptosis signal-regulating kinase 1 is a key factor in paraquat-induced cell death : modulation by the Nrf2/Trx axis

    NARCIS (Netherlands)

    Niso-Santano, Mireia; González-Polo, Rosa A; Bravo-San Pedro, José M; Gómez-Sánchez, Rubén; Lastres-Becker, Isabel; Ortiz-Ortiz, Miguel A; Soler, Germán; Morán, José M; Cuadrado, Antonio; Fuentes, José M

    2010-01-01

    Although oxidative stress is fundamental to the etiopathology of Parkinson disease, the signaling molecules involved in transduction after oxidant exposure to cell death are ill-defined, thus making it difficult to identify molecular targets of therapeutic relevance. We have addressed this question

  20. CD4+ type II NKT cells mediate ICOS and programmed death-1-dependent regulation of type 1 diabetes

    DEFF Research Database (Denmark)

    Kadri, Nadir; Korpos, Eva; Gupta, Shashank

    2012-01-01

    Type 1 diabetes (T1D) is a chronic autoimmune disease that results from T cell-mediated destruction of pancreatic ß cells. CD1d-restricted NKT lymphocytes have the ability to regulate immunity, including autoimmunity. We previously demonstrated that CD1d-restricted type II NKT cells, which carry ...

  1. Cell Death in the Developing Brain after Hypoxia-Ischemia

    Science.gov (United States)

    Thornton, Claire; Leaw, Bryan; Mallard, Carina; Nair, Syam; Jinnai, Masako; Hagberg, Henrik

    2017-01-01

    Perinatal insults such as hypoxia–ischemia induces secondary brain injury. In order to develop the next generation of neuroprotective therapies, we urgently need to understand the underlying molecular mechanisms leading to cell death. The cell death mechanisms have been shown to be quite different in the developing brain compared to that in the adult. The aim of this review is update on what cell death mechanisms that are operating particularly in the setting of the developing CNS. In response to mild stress stimuli a number of compensatory mechanisms will be activated, most often leading to cell survival. Moderate-to-severe insults trigger regulated cell death. Depending on several factors such as the metabolic situation, cell type, nature of the stress stimulus, and which intracellular organelle(s) are affected, the cell undergoes apoptosis (caspase activation) triggered by BAX dependent mitochondrial permeabilzation, necroptosis (mixed lineage kinase domain-like activation), necrosis (via opening of the mitochondrial permeability transition pore), autophagic cell death (autophagy/Na+, K+-ATPase), or parthanatos (poly(ADP-ribose) polymerase 1, apoptosis-inducing factor). Severe insults cause accidental cell death that cannot be modulated genetically or by pharmacologic means. However, accidental cell death leads to the release of factors (damage-associated molecular patterns) that initiate systemic effects, as well as inflammation and (regulated) secondary brain injury in neighboring tissue. Furthermore, if one mode of cell death is inhibited, another route may step in at least in a scenario when upstream damaging factors predominate over protective responses. The provision of alternative routes through which the cell undergoes death has to be taken into account in the hunt for novel brain protective strategies. PMID:28878624

  2. Heat stress induces ferroptosis-like cell death in plants.

    Science.gov (United States)

    Distéfano, Ayelén Mariana; Martin, María Victoria; Córdoba, Juan Pablo; Bellido, Andrés Martín; D'Ippólito, Sebastián; Colman, Silvana Lorena; Soto, Débora; Roldán, Juan Alfredo; Bartoli, Carlos Guillermo; Zabaleta, Eduardo Julián; Fiol, Diego Fernando; Stockwell, Brent R; Dixon, Scott J; Pagnussat, Gabriela Carolina

    2017-02-01

    In plants, regulated cell death (RCD) plays critical roles during development and is essential for plant-specific responses to abiotic and biotic stresses. Ferroptosis is an iron-dependent, oxidative, nonapoptotic form of cell death recently described in animal cells. In animal cells, this process can be triggered by depletion of glutathione (GSH) and accumulation of lipid reactive oxygen species (ROS). We investigated whether a similar process could be relevant to cell death in plants. Remarkably, heat shock (HS)-induced RCD, but not reproductive or vascular development, was found to involve a ferroptosis-like cell death process. In root cells, HS triggered an iron-dependent cell death pathway that was characterized by depletion of GSH and ascorbic acid and accumulation of cytosolic and lipid ROS. These results suggest a physiological role for this lethal pathway in response to heat stress in Arabidopsis thaliana The similarity of ferroptosis in animal cells and ferroptosis-like death in plants suggests that oxidative, iron-dependent cell death programs may be evolutionarily ancient. © 2017 Distéfano et al.

  3. A novel neuron-enriched protein SDIM1 is down regulated in Alzheimer's brains and attenuates cell death induced by DNAJB4 over-expression in neuro-progenitor cells

    Directory of Open Access Journals (Sweden)

    Lei Joy X

    2011-01-01

    Full Text Available Abstract Background Molecular changes in multiple biological processes contribute to the development of chronic neurodegeneration such as late onset Alzheimer's disease (LOAD. To discover how these changes are reflected at the level of gene expression, we used a subtractive transcription-based amplification of mRNA procedure to identify novel genes that have altered expression levels in the brains of Alzheimer's disease (AD patients. Among the genes altered in expression level in AD brains was a transcript encoding a novel protein, SDIM1, that contains 146 amino acids, including a typical signal peptide and two transmembrane domains. Here we examined its biochemical properties and putative roles in neuroprotection/neurodegeneration. Results QRT-PCR analysis of additional AD and control post-mortem human brains showed that the SDIM1 transcript was indeed significantly down regulated in all AD brains. SDIM1 is more abundant in NT2 neurons than astrocytes and present throughout the cytoplasm and neural processes, but not in the nuclei. In NT2 neurons, it is highly responsive to stress conditions mimicking insults that may cause neurodegeneration in AD brains. For example, SDIM1 was significantly down regulated 2 h after oxygen-glucose deprivation (OGD, though had recovered 16 h later, and also appeared significantly up regulated compared to untreated NT2 neurons. Overexpression of SDIM1 in neuro-progenitor cells improved cells' ability to survive after injurious insults and its downregulation accelerated cell death induced by OGD. Yeast two-hybrid screening and co-immunoprecipitation approaches revealed, both in vitro and in vivo, an interaction between SDIM1 and DNAJB4, a heat shock protein hsp40 homolog, recently known as an enhancer of apoptosis that also interacts with the mu opioid receptor in human brain. Overexpression of DNAJB4 alone significantly reduced cell viability and SDIM1 co-overexpression was capable of attenuating the cell death

  4. Induction of apoptotic cell death by putrescine

    DEFF Research Database (Denmark)

    Takao, Koichi; Rickhag, Karl Mattias; Hegardt, Cecilia

    2006-01-01

    for their growth. The induction of cell death was correlated with a dramatic increase in cellular putrescine levels. Analysis using flow cytometry revealed perturbed cell cycle kinetics, with a large accumulation of cells with sub-G1 amounts of DNA, which is a typical sign of apoptosis. Another strong indication...... homeostasis may negatively affect cell proliferation and eventually lead to cell death by apoptosis if putrescine levels become too high....

  5. Programmed Cell Death in Unicellular Phytoplankton.

    Science.gov (United States)

    Bidle, Kay D

    2016-07-11

    Unicellular, planktonic, prokaryotic and eukaryotic photoautotrophs (phytoplankton) have an ancient evolutionary history on Earth during which time they have played key roles in the regulation of marine food webs, biogeochemical cycles, and Earth's climate. Since they represent the basis of aquatic ecosystems, the manner in which phytoplankton die critically determines the flow and fate of photosynthetically fixed organic matter (and associated elements), ultimately constraining nutrient flow. Programmed cell death (PCD) and associated pathway genes, which are triggered by a variety of abiotic (nutrient, light, osmotic) and biotic (virus infection, allelopathy) environmental stresses, have an integral grip on cell fate, and have shaped the ecological success and evolutionary trajectory of diverse phytoplankton lineages. A combination of physiological, biochemical, and genetic techniques in model algal systems has demonstrated a conserved molecular and mechanistic framework of stress surveillance, signaling, and death activation pathways, involving collective and coordinated participation of organelles, redox enzymes, metabolites, and caspase-like proteases. This mechanistic understanding has provided insight into the integration of sensing and transduction of stress signals into cellular responses, and the mechanistic interfaces between PCD, cell stress and virus infection pathways. It has also provided insight into the evolution of PCD in unicellular photoautotrophs, the impact of PCD on the fate of natural phytoplankton assemblages and its role in aquatic biogeochemical cycles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Non-apoptotic Cell Death in Malignant Tumor Cells and Natural Compounds.

    Science.gov (United States)

    Ye, Jing; Zhang, Ruonan; Wu, Fan; Zhai, Lijuan; Wang, Kaifeng; Xiao, Mang; Xie, Tian; Sui, Xinbing

    2018-01-30

    Traditional cancer therapy is mainly targeting on enhancing cell apoptosis, however, it is well established that many cancer cells are chemo-resistant and defective in apoptosis induction. Therefore, it may have important therapeutic implications to exploit some novel natural compounds based on non-apoptotic programmed cell death. Currently, accumulating evidence shows that the compounds from nature source can induce non-apoptotic programmed cell death in cancer cells, and therefore these natural compounds have gained a great promise for the future anticancer therapeutics. In this review, we will concentrate our efforts on the latest developments regarding major forms of non-apoptotic programmed cell death--autophagic cell death, necroptosis, ferroptosis, pyroptosis, glutamoptosis and exosome-associated cell death. Our increased understanding of the role of natural compounds in regulating non-apoptotic programmed cell death will hopefully provide prospective strategies for cancer therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Cell death sensitization of leukemia cells by opioid receptor activation.

    Science.gov (United States)

    Friesen, Claudia; Roscher, Mareike; Hormann, Inis; Fichtner, Iduna; Alt, Andreas; Hilger, Ralf A; Debatin, Klaus-Michael; Miltner, Erich

    2013-05-01

    Cyclic AMP (cAMP) regulates a number of cellular processes and modulates cell death induction. cAMP levels are altered upon stimulation of specific G-protein-coupled receptors inhibiting or activating adenylyl cyclases. Opioid receptor stimulation can activate inhibitory Gi-proteins which in turn block adenylyl cyclase activity reducing cAMP. Opioids such as D,L-methadone induce cell death in leukemia cells. However, the mechanism how opioids trigger apoptosis and activate caspases in leukemia cells is not understood. In this study, we demonstrate that downregulation of cAMP induced by opioid receptor activation using the opioid D,L-methadone kills and sensitizes leukemia cells for doxorubicin treatment. Enhancing cAMP levels by blocking opioid-receptor signaling strongly reduced D,L-methadone-induced apoptosis, caspase activation and doxorubicin-sensitivity. Induction of cell death in leukemia cells by activation of opioid receptors using the opioid D,L-methadone depends on critical levels of opioid receptor expression on the cell surface. Doxorubicin increased opioid receptor expression in leukemia cells. In addition, the opioid D,L-methadone increased doxorubicin uptake and decreased doxorubicin efflux in leukemia cells, suggesting that the opioid D,L-methadone as well as doxorubicin mutually increase their cytotoxic potential. Furthermore, we found that opioid receptor activation using D,L-methadone alone or in addition to doxorubicin inhibits tumor growth significantly in vivo. These results demonstrate that opioid receptor activation via triggering the downregulation of cAMP induces apoptosis, activates caspases and sensitizes leukemia cells for doxorubicin treatment. Hence, opioid receptor activation seems to be a promising strategy to improve anticancer therapies.

  8. Deletion of apoptosis signal-regulating kinase 1 (ASK1 protects pancreatic beta-cells from stress-induced death but not from glucose homeostasis alterations under pro-inflammatory conditions.

    Directory of Open Access Journals (Sweden)

    Emilie Pepin

    Full Text Available Type 2 diabetes is characterized by pancreatic beta-cell dysfunction and is associated with low-grade inflammation. Recent observations suggest that apoptosis signal-regulating kinase 1 (ASK1 is involved in beta-cell death in response to different stressors. In this study, we tested whether ASK1 deficiency protects beta-cells from glucolipotoxic conditions and cytokines treatment or from glucose homeostasis alteration induced by endotoxemia.Insulin secretion was neither affected upon shRNA-mediated downregulation of ASK1 in MIN6 cells nor in islets from ASK1-deficient mice. ASK1 silencing in MIN6 cells and deletion in islets did not prevent the deleterious effect of glucolipotoxic conditions or cytokines on insulin secretion. However, it protected MIN6 cells from death induced by ER stress or palmitate and islets from short term caspase activation in response to cytokines. Moreover, endotoxemia induced by LPS infusion increased insulin secretion during hyperglycemic clamps but the response was similar in wild-type and ASK1-deficient mice. Finally, insulin sensitivity in the presence of LPS was not affected by ASK1-deficiency.Our study demonstrates that ASK1 is not involved in beta-cell function and dysfunction but controls stress-induced beta-cell death.

  9. Death Pathways Triggered by Activated Ras in Cancer Cells

    Science.gov (United States)

    Overmeyer, Jean H.; Maltese, William A.

    2011-01-01

    Ras GTPases are best known for their ability to serve as molecular switches regulating cell growth, differentiation and survival. Gene mutations that result in expression of constitutively active forms of Ras proteins have been clearly linked to oncogenesis in animal models and humans. However, over the past two decades, evidence has gradually accumulated to support a paradoxical role for Ras proteins in the initiation of cell death pathways. The balance between the opposing functions of Ras in cell proliferation/survival versus cell death can be critical for determining the overall fate of the cancer cell. In this review we will survey the body of literature that points to the ability of activated Ras proteins to tip the scales toward cell death under conditions where cancer cells encounter adverse environmental conditions or are subjected to apoptotic stimuli. In some cases the consequences of Ras activation are mediated through interactions with known effectors and well defined apoptotic death pathways. However, in other cases it appears that Ras operates by triggering novel non-apoptotic death mechanisms that are just beginning to be characterized. Understanding the details of these pathways, and the various factors that go into changing the nature of Ras signaling from pro-survival to pro-death, could potentially set the stage for the development of novel therapeutic approaches aimed at manipulating the pro-death Ras effector pathways in cancers. PMID:21196257

  10. Early cell death detection with digital holographic microscopy.

    Directory of Open Access Journals (Sweden)

    Nicolas Pavillon

    Full Text Available BACKGROUND: Digital holography provides a non-invasive measurement of the quantitative phase shifts induced by cells in culture, which can be related to cell volume changes. It has been shown previously that regulation of cell volume, in particular as it relates to ionic homeostasis, is crucially involved in the activation/inactivation of the cell death processes. We thus present here an application of digital holographic microscopy (DHM dedicated to early and label-free detection of cell death. METHODS AND FINDINGS: We provide quantitative measurements of phase signal obtained on mouse cortical neurons, and caused by early neuronal cell volume regulation triggered by excitotoxic concentrations of L-glutamate. We show that the efficiency of this early regulation of cell volume detected by DHM, is correlated with the occurrence of subsequent neuronal death assessed with the widely accepted trypan blue method for detection of cell viability. CONCLUSIONS: The determination of the phase signal by DHM provides a simple and rapid optical method for the early detection of cell death.

  11. Programmed cell death during quinoa perisperm development

    OpenAIRE

    L?pez-Fern?ndez, Mar?a Paula; Maldonado,Sara

    2013-01-01

    At seed maturity, quinoa (Chenopodium quinoa Willd.) perisperm consists of uniform, non-living, thin-walled cells full of starch grains. The objective of the present study was to study quinoa perisperm development and describe the programme of cell death that affects the entire tissue. A number of parameters typically measured during programmed cell death (PCD), such as cellular morphological changes in nuclei and cytoplasm, endoreduplication, DNA fragmentation, and the participation of nucle...

  12. Autophagic components contribute to hypersensitive cell death in Arabidopsis

    DEFF Research Database (Denmark)

    Hofius, Daniel; Schultz-Larsen, Torsten; Joensen, Jan

    2009-01-01

    expression. Here, we examined receptor-mediated HR PCD responses in autophagy-deficient Arabidopsis knockout mutants (atg), and show that infection-induced lesions are contained in atg mutants. We also provide evidence that HR cell death initiated via Toll/Interleukin-1 (TIR)-type immune receptors through...... the defense regulator EDS1 is suppressed in atg mutants. Furthermore, we demonstrate that PCD triggered by coiled-coil (CC)-type immune receptors via NDR1 is either autophagy-independent or engages autophagic components with cathepsins and other unidentified cell death mediators. Thus, autophagic cell death......Autophagy has been implicated as a prosurvival mechanism to restrict programmed cell death (PCD) associated with the pathogen-triggered hypersensitive response (HR) during plant innate immunity. This model is based on the observation that HR lesions spread in plants with reduced autophagy gene...

  13. Activation of intracellular angiotensin AT2 receptors induces rapid cell death in human uterine leiomyosarcoma cells

    DEFF Research Database (Denmark)

    Zhao, Yi; Lützen, Ulf; Fritsch, Jürgen

    2015-01-01

    of apoptosis and cell death in cultured human uterine leiomyosarcoma (SK-UT-1) cells and control human uterine smooth muscle cells (HutSMC). The intracellular levels of the AT2 receptor are low in proliferating SK-UT-1 cells but the receptor is substantially up-regulated in quiescent SK-UT-1 cells with high...... densities in mitochondria. Activation of the cell membrane AT2 receptors by a concomitant treatment with angiotensin II and the AT1 receptor antagonist, losartan, induces apoptosis but does not affect the rate of cell death. We demonstrate for the first time that the high-affinity, non-peptide AT2 receptor...... agonist, Compound 21 (C21) penetrates the cell membrane of quiescent SK-UT-1 cells, activates intracellular AT2 receptors and induces rapid cell death; approximately 70% of cells died within 24 h. The cells, which escaped from the cell death, displayed activation of the mitochondrial apoptotic pathway, i...

  14. Cell death induced by endoplasmic reticulum stress.

    Science.gov (United States)

    Iurlaro, Raffaella; Muñoz-Pinedo, Cristina

    2016-07-01

    The endoplasmic reticulum is an organelle with multiple functions. The synthesis of transmembrane proteins and proteins that are to be secreted occurs in this organelle. Many conditions that impose stress on cells, including hypoxia, starvation, infections and changes in secretory needs, challenge the folding capacity of the cell and promote endoplasmic reticulum stress. The cellular response involves the activation of sensors that transduce signaling cascades with the aim of restoring homeostasis. This is known as the unfolded protein response, which also intersects with the integrated stress response that reduces protein synthesis through inactivation of the initiation factor eIF2α. Central to the unfolded protein response are the sensors PERK, IRE1 and ATF6, as well as other signaling nodes such as c-Jun N-terminal kinase 1 (JNK) and the downstream transcription factors XBP1, ATF4 and CHOP. These proteins aim to restore homeostasis, but they can also induce cell death, which has been shown to occur by necroptosis and, more commonly, through the regulation of Bcl-2 family proteins (Bim, Noxa and Puma) that leads to mitochondrial apoptosis. In addition, endoplasmic reticulum stress and proteotoxic stress have been shown to induce TRAIL receptors and activation of caspase-8. Endoplasmic reticulum stress is a common feature in the pathology of numerous diseases because it plays a role in neurodegeneration, stroke, cancer, metabolic diseases and inflammation. Understanding how cells react to endoplasmic reticulum stress can accelerate discovery of drugs against these diseases. © 2015 FEBS.

  15. Lysosomal cell death at a glance

    DEFF Research Database (Denmark)

    Aits, Sonja; Jaattela, Marja

    2013-01-01

    Lysosomes serve as the cellular recycling centre and are filled with numerous hydrolases that can degrade most cellular macromolecules. Lysosomal membrane permeabilization and the consequent leakage of the lysosomal content into the cytosol leads to so-called "lysosomal cell death". This form...... of cell death is mainly carried out by the lysosomal cathepsin proteases and can have necrotic, apoptotic or apoptosis-like features depending on the extent of the leakage and the cellular context. This article summarizes our current knowledge on lysosomal cell death with an emphasis on the upstream...... mechanisms that lead to lysosomal membrane permeabilization....

  16. SWCNTs induced autophagic cell death in human bronchial epithelial cells.

    Science.gov (United States)

    Park, Eun-Jung; Zahari, Nur Elida M; Lee, Eun-Woo; Song, Jaewhan; Lee, Jae-Hyeok; Cho, Myung-Haing; Kim, Jae-Ho

    2014-04-01

    Carbon nanotubes are being actively introduced in electronics, computer science, aerospace, and other industries. Thus, the urgent need for toxicological studies on CNTs is mounting. In this study, we investigated the alterations in cellular response with morphological changes induced by single-walled carbon nanotubes (SWCNTs) in BEAS-2B cells, a human bronchial epithelial cell line. At 24h after exposure, SWCNTs rapidly decreased ATP production and cell viability as well a slight increase in the number of cells in the subG1 and G1 phases. In addition, SWCNTs increased the expression of superoxide dismutase (SOD)-1, but not SOD-2, and the number of cells generating ROS. The concentration of Cu and Zn ions also increased in a dose-dependent manner in cells exposed to SWCNTs. SWCNTs significantly enhanced the release of nitric oxide, interleukin (IL)-6, and IL-8 and up-regulated the expression of chemokine- and cytokine-related genes. Furthermore, the levels of autophagy-related genes, especially the DRAM1 gene, and the autophagosome formation-related proteins, were clearly up-regulated together with an increase of autophagosome-like vacuoles. Based on these results, we suggest that SWCNTs induce autophagic cell death through mitochondrial dysfunction and cytosolic damage in human bronchial epithelial cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Synergy between sulforaphane and selenium in the up-regulation of thioredoxin reductase and protection against hydrogen peroxide-induced cell death in human hepatocytes.

    Science.gov (United States)

    Li, Dan; Wang, Wei; Shan, Yujuan; Barrera, Lawrence N; Howie, Alexander F; Beckett, Geoffrey J; Wu, Kun; Bao, Yongping

    2012-07-15

    Dietary isothiocyanates and selenium are chemopreventive agents and potent inducers of antioxidant enzymes. It has been previously shown that sulforaphane and selenium have a synergistic effect on the upregulation of thioredoxin reductase-1 (TrxR-1) in human hepatoma HepG2 cells. In this paper, further evidence is presented to show that sulforaphane and selenium synergistically induce TrxR-1 expression in immortalised human hepatocytes. Sulforaphane was found to be more toxic toward hepatocytes than HepG2 cells with IC50=25.1 and 56.4 μM, respectively. Sulforaphane can protect against hydrogen peroxide-induced cell death and this protection was enhanced by co-treatment with selenium. Using siRNA to knock down TrxR-1 or Nrf2, sulforaphane (5 μM)-protected cell viability was reduced from 73% to 46% and 34%, respectively, suggesting that TrxR-1 is an important enzyme in protection against hydrogen peroxide-induced cell death. Sulforaphane-induced TrxR-1 expression was positively associated with significant levels of Nrf2 translocation into the nucleus, but co-treatment with selenium showed no significant increase in Nrf2 translocation. Moreover, MAPK (ERK, JNK and p38) and PI3K/Akt signalling pathways were found to play no significant role in sulforaphane-induced Nrf2 translocation into the nucleus. However, blocking ERK and JNK signalling pathways decreased sulforaphane-induced TrxR-1 mRNA by about 20%; whereas blocking p38 and PI3K/AKT increased TrxR-1 transcription. In summary, a combination of sulforaphane and selenium resulted in a synergistic upregulation of TrxR-1 that contributed to the enhanced protection against free radical-mediated oxidative damage in human hepatocytes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Nuclear apoJ: A low dose radiation inducible regulator of cell death. Final report for period September 15, 1998 - September 14, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Aronow, Bruce J.

    2002-04-19

    This project was based on preliminary data that was published by Dr. Boothman (Yang et al. 2000) which indicated a strong induction of apoJ gene expression, increased secretion of the protein, and accumulation of an apparently somewhat different form of the apoJ protein in the nucleus of MCF-7 breast carcinoma cells undergoing response to DNA damage. A clone expressing apoJ protein was isolated that was capable of interacting with Ku80, a component of the double strand break repair complex that is essential for the successful repair of rearranging immunoglobulin and T-cell receptor genes as evidenced by failure to produce mature B and T cells in the absence of Ku70. ApoJ clones isolated and characterized by Dr. Boothman bound strongly to a Ku-70 ''bait'' protein. Over-expression of these same clones in a cell line was capable of killing the cell. ApoJ is very strongly induced in many instances of programmed cell death and has been proposed repeatedly to play some sort of effector role in the process. Our principle hypothesis for this study was that the strong induction of the apoJ gene and the particular expression of a nuclear form of the protein was potentially a causal factor in the decision point made by the cell as it attempts to repair double-strand breakage based DNA damage. The hypothesis was that if sufficiently high damage occurred, it would be deleterious to maintain the cell's viability through continued DNA repair. One method to inhibit DNA repair might be by inhibiting proteins such as Ku-70 that are necessary for double-strand break repair. If apoJ does play a critical role in tipping the decision balance over to cell death, we reasoned that deficiency of apoJ would cause increased accumulation of cells with DNA damage and that this might decrease cell death in response to DNA damage and increase tumor occurrence rates. To test this hypothesis and its potential implications, we exposed wildtype and apoJ deficient animals that

  19. Programmed cell death – strategy for maintenance cellular organisms homeostasis

    Directory of Open Access Journals (Sweden)

    Mirosław Godlewski

    2016-12-01

    Full Text Available Programmed cell death (PCD is a cellular suicide process, commonly found in organisms, that is important for elimination unnecessary and damaged cells during development and adaptation to abiotic and biotic environmental stresses. PCD is a complex and precise, genetically controlled cellular process, in opposite to non-programmed death, necrosis, in which cells are “killed” by strong abiotic factors. This article shows: the occurrence of PCD during animals and plants ontogenesis, classification of cell death types in these organisms with description of autophagy, apoptosis and necrotic cell death and with discussion on plant cell death by apoptosis. The role of Bcl-2 protein and other proteins involved in the regulation of apoptosis induction and detection in the plant’s (whose genomes do not encode these proteins proteins of analogous function is also discussed. The paper also presents the effects of the expression of animals pro- and anti-apoptotic genes transformed into yeast and plants, and the use of transformed yeast as model to identify in cDNA libraries animal and plant genes involved in regulation of the induction and course of the PCD.

  20. SERCA control of cell death and survival.

    Science.gov (United States)

    Chemaly, Elie R; Troncone, Luca; Lebeche, Djamel

    2018-01-01

    Intracellular calcium (Ca2+) is a critical coordinator of various aspects of cellular physiology. It is increasingly apparent that changes in cellular Ca2+ dynamics contribute to the regulation of normal and pathological signal transduction that controls cell growth and survival. Aberrant perturbations in Ca2+ homeostasis have been implicated in a range of pathological conditions, such as cardiovascular diseases, diabetes, tumorigenesis and steatosis hepatitis. Intracellular Ca2+ concentrations are therefore tightly regulated by a number of Ca2+ handling enzymes, proteins, channels and transporters located in the plasma membrane and in Ca2+ storage organelles, which work in concert to fine tune a temporally and spatially precise Ca2+ signal. Chief amongst them is the sarco/endoplasmic reticulum (SR/ER) Ca2+ ATPase pump (SERCA) which actively re-accumulates released Ca2+ back into the SR/ER, therefore maintaining Ca2+ homeostasis. There are at least 14 different SERCA isoforms encoded by three ATP2A1-3 genes whose expressions are species- and tissue-specific. Altered SERCA expression and activity results in cellular malignancy and induction of ER stress and ER stress-associated apoptosis. The role of SERCA misregulation in the control of apoptosis in various cell types and disease setting with prospective therapeutic implications is the focus of this review. Ca2+ is a double edge sword for both life as well as death, and current experimental evidence supports a model in which Ca2+ homeostasis and SERCA activity represent a nodal point that controls cell survival. Pharmacological or genetic targeting of this axis constitutes an incredible therapeutic potential to treat different diseases sharing similar biological disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018

    NARCIS (Netherlands)

    Galluzzi, Lorenzo; Vitale, Ilio; Aaronson, Stuart A.; Abrams, John M.; Adam, Dieter; Agostinis, Patrizia; Alnemri, Emad S.; Altucci, Lucia; Amelio, Ivano; Andrews, David W.; Annicchiarico-Petruzzelli, Margherita; Antonov, Alexey V.; Arama, Eli; Baehrecke, Eric H.; Barlev, Nickolai A.; Bazan, Nicolas G.; Bernassola, Francesca; Bertrand, Mathieu J. M.; Bianchi, Katiuscia; Blagosklonny, Mikhail V.; Blomgren, Klas; Borner, Christoph; Boya, Patricia; Brenner, Catherine; Campanella, Michelangelo; Candi, Eleonora; Carmona-Gutierrez, Didac; Cecconi, Francesco; Chan, Francis K.-M.; Chandel, Navdeep S.; Cheng, Emily H.; Chipuk, Jerry E.; Cidlowski, John A.; Ciechanover, Aaron; Cohen, Gerald M.; Conrad, Marcus; Cubillos-Ruiz, Juan R.; Czabotar, Peter E.; D'Angiolella, Vincenzo; Dawson, Ted M.; Dawson, Valina L.; de Laurenzi, Vincenzo; de Maria, Ruggero; Debatin, Klaus-Michael; DeBerardinis, Ralph J.; Deshmukh, Mohanish; Di Daniele, Nicola; Di Virgilio, Francesco; Dixit, Vishva M.; Dixon, Scott J.; Duckett, Colin S.; Dynlacht, Brian D.; El-Deiry, Wafik S.; Elrod, John W.; Fimia, Gian Maria; Fulda, Simone; García-Sáez, Ana J.; Garg, Abhishek D.; Garrido, Carmen; Gavathiotis, Evripidis; Golstein, Pierre; Gottlieb, Eyal; Green, Douglas R.; Greene, Lloyd A.; Gronemeyer, Hinrich; Gross, Atan; Hajnoczky, Gyorgy; Hardwick, J. Marie; Harris, Isaac S.; Hengartner, Michael O.; Hetz, Claudio; Ichijo, Hidenori; Jäättelä, Marja; Joseph, Bertrand; Jost, Philipp J.; Juin, Philippe P.; Kaiser, William J.; Karin, Michael; Kaufmann, Thomas; Kepp, Oliver; Kimchi, Adi; Kitsis, Richard N.; Klionsky, Daniel J.; Knight, Richard A.; Kumar, Sharad; Lee, Sam W.; Lemasters, John J.; Levine, Beth; Linkermann, Andreas; Lipton, Stuart A.; Lockshin, Richard A.; López-Otín, Carlos; Lowe, Scott W.; Luedde, Tom; Lugli, Enrico; MacFarlane, Marion; Madeo, Frank; Malewicz, Michal; Malorni, Walter; Manic, Gwenola; Marine, Jean-Christophe; Martin, Seamus J.; Martinou, Jean-Claude; Medema, Jan Paul; Mehlen, Patrick; Meier, Pascal; Melino, Sonia; Miao, Edward A.; Molkentin, Jeffery D.; Moll, Ute M.; Muñoz-Pinedo, Cristina; Nagata, Shigekazu; Nuñez, Gabriel; Oberst, Andrew; Oren, Moshe; Overholtzer, Michael; Pagano, Michele; Panaretakis, Theocharis; Pasparakis, Manolis; Penninger, Josef M.; Pereira, David M.; Pervaiz, Shazib; Peter, Marcus E.; Piacentini, Mauro; Pinton, Paolo; Prehn, Jochen H. M.; Puthalakath, Hamsa; Rabinovich, Gabriel A.; Rehm, Markus; Rizzuto, Rosario; Rodrigues, Cecilia M. P.; Rubinsztein, David C.; Rudel, Thomas; Ryan, Kevin M.; Sayan, Emre; Scorrano, Luca; Shao, Feng; Shi, Yufang; Silke, John; Simon, Hans-Uwe; Sistigu, Antonella; Stockwell, Brent R.; Strasser, Andreas; Szabadkai, Gyorgy; Tait, Stephen W. G.; Tang, Daolin; Tavernarakis, Nektarios; Thorburn, Andrew; Tsujimoto, Yoshihide; Turk, Boris; Vanden Berghe, Tom; Vandenabeele, Peter; Vander Heiden, Matthew G.; Villunger, Andreas; Virgin, Herbert W.; Vousden, Karen H.; Vucic, Domagoj; Wagner, Erwin F.; Walczak, Henning; Wallach, David; Wang, Ying; Wells, James A.; Wood, Will; Yuan, Junying; Zakeri, Zahra; Zhivotovsky, Boris; Zitvogel, Laurence; Melino, Gerry; Kroemer, Guido

    2018-01-01

    Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell

  2. Artesunate induces necrotic cell death in schwannoma cells.

    Science.gov (United States)

    Button, R W; Lin, F; Ercolano, E; Vincent, J H; Hu, B; Hanemann, C O; Luo, S

    2014-10-16

    Established as a potent anti-malaria medicine, artemisinin-based drugs have been suggested to have anti-tumour activity in some cancers. Although the mechanism is poorly understood, it has been suggested that artemisinin induces apoptotic cell death. Here, we show that the artemisinin analogue artesunate (ART) effectively induces cell death in RT4 schwannoma cells and human primary schwannoma cells. Interestingly, our data indicate for first time that the cell death induced by ART is largely dependent on necroptosis. ART appears to inhibit autophagy, which may also contribute to the cell death. Our data in human schwannoma cells show that ART can be combined with the autophagy inhibitor chloroquine (CQ) to potentiate the cell death. Thus, this study suggests that artemisinin-based drugs may be used in certain tumours where cells are necroptosis competent, and the drugs may act in synergy with apoptosis inducers or autophagy inhibitors to enhance their anti-tumour activity.

  3. Guidelines and recommendations on yeast cell death nomenclature

    Directory of Open Access Journals (Sweden)

    Didac Carmona-Gutierrez

    2018-01-01

    Full Text Available Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death routines that are relevant for the biology of (at least some species of yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the authors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the progress of this vibrant field of research.

  4. Cell Death and Cell Death Responses in Liver Disease: Mechanisms and Clinical Relevance

    Science.gov (United States)

    Luedde, Tom; Kaplowitz, Neil; Schwabe, Robert F.

    2015-01-01

    Summary Hepatocellular death is present in almost all types of human liver disease and is used as a sensitive parameter for the detection of acute and chronic liver disease of viral, toxic, metabolic, or autoimmune origin. Clinical data and animal models suggest that hepatocyte death is the key trigger of liver disease progression, manifested by the subsequent development of inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma. Modes of hepatocellular death differ substantially between liver diseases. Different modes of cell death such as apoptosis, necrosis, and necroptosis trigger specific cell death responses and promote progression of liver disease through distinct mechanisms. In this review, we first discuss molecular mechanisms by which different modes of cell death, damage-associated molecular patterns, and specific cell death responses contribute to the development of liver disease. We then review the clinical relevance of cell death, focusing on biomarkers; the contribution of cell death to drug-induced, viral, and fatty liver disease and liver cancer; and evidence for cell death pathways as therapeutic targets. PMID:25046161

  5. Pannexin1 as mediator of inflammation and cell death.

    Science.gov (United States)

    Crespo Yanguas, Sara; Willebrords, Joost; Johnstone, Scott R; Maes, Michaël; Decrock, Elke; De Bock, Marijke; Leybaert, Luc; Cogliati, Bruno; Vinken, Mathieu

    2017-01-01

    Pannexins form channels at the plasma membrane surface that establish a pathway for communication between the cytosol of individual cells and their extracellular environment. By doing so, pannexin signaling dictates several physiological functions, but equally underlies a number of pathological processes. Indeed, pannexin channels drive inflammation by assisting in the activation of inflammasomes, the release of pro-inflammatory cytokines, and the activation and migration of leukocytes. Furthermore, these cellular pores facilitate cell death, including apoptosis, pyroptosis and autophagy. The present paper reviews the roles of pannexin channels in inflammation and cell death. In a first part, a state-of-the-art overview of pannexin channel structure, regulation and function is provided. In a second part, the mechanisms behind their involvement in inflammation and cell death are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Centrality of host cell death in plant-microbe interactions.

    Science.gov (United States)

    Dickman, Martin B; Fluhr, Robert

    2013-01-01

    Programmed cell death (PCD) is essential for proper growth, development, and cellular homeostasis in all eukaryotes. The regulation of PCD is of central importance in plant-microbe interactions; notably, PCD and features associated with PCD are observed in many host resistance responses. Conversely, pathogen induction of inappropriate cell death in the host results in a susceptible phenotype and disease. Thus, the party in control of PCD has a distinct advantage in these battles. PCD processes appear to be of ancient origin, as indicated by the fact that many features of cell death strategy are conserved between animals and plants; however, some of the details of death execution differ. Mammalian core PCD genes, such as caspases, are not present in plant genomes. Similarly, pro- and antiapoptotic mammalian regulatory elements are absent in plants, but, remarkably, when expressed in plants, successfully impact plant PCD. Thus, subtle structural similarities independent of sequence homology appear to sustain operational equivalence. The vacuole is emerging as a key organelle in the modulation of plant PCD. Under different signals for cell death, the vacuole either fuses with the plasmalemma membrane or disintegrates. Moreover, the vacuole appears to play a key role in autophagy; evidence suggests a prosurvival function for autophagy, but other studies propose a prodeath phenotype. Here, we describe and discuss what we know and what we do not know about various PCD pathways and how the host integrates signals to activate salicylic acid and reactive oxygen pathways that orchestrate cell death. We suggest that it is not cell death as such but rather the processes leading to cell death that contribute to the outcome of a given plant-pathogen interaction.

  7. The Apoptosome: Heart and Soul of the Cell Death Machine

    Directory of Open Access Journals (Sweden)

    Arul M. Chinnaiyan

    1999-04-01

    Full Text Available Apoptosis is a fundamental biologic process by which metazoan cells orchestrate their own self-demise. Genetic analyses of the nematode C elegans identified three core components of the suicide apparatus which include CED-3, CED-4, and CED-9. An analogous set of core constituents exists in mammalian cells and includes caspase-9, Apaf-1, and bcl-2/xL, respectively. CED-3 and CED-4, along with their mammalian counterparts, function to kill cells, whereas CED-9 and its mammalian equivalents protect cells from death. These central components biochemically intermingle in a ternary complex recently dubbed the “apoptosome.” The C elegans protein EGL-1 and its mammalian counterparts, pro-apoptotic members of the bcl-2 family, induce cell death by disrupting apoptosome interactions. Thus, EGL-1 may represent a primordial signal integrator for the apoptosome. Various biochemical processes including oligomerization, adenosine triphosphate ATP/dATP binding, and cytochrome c interaction play a role in regulating the ternary death complex. Recent studies suggest that cell death receptors, such as CD95, may amplify their suicide signal by activating the apoptosome. These mutual associations by core components of the suicide apparatus provide a molecular framework in which diverse death signals likely interface. Understanding the apoptosome and its cellular connections will facilitate the design of novel therapeutic strategies for cancer and other disease states in which apoptosis plays a pivotal role.

  8. How Kidney Cell Death Induces Renal Necroinflammation.

    Science.gov (United States)

    Mulay, Shrikant R; Kumar, Santhosh V; Lech, Maciej; Desai, Jyaysi; Anders, Hans-Joachim

    2016-05-01

    The nephrons of the kidney are independent functional units harboring cells of a low turnover during homeostasis. As such, physiological renal cell death is a rather rare event and dead cells are flushed away rapidly with the urinary flow. Renal cell necrosis occurs in acute kidney injuries such as thrombotic microangiopathies, necrotizing glomerulonephritis, or tubular necrosis. All of these are associated with intense intrarenal inflammation, which contributes to further renal cell loss, an autoamplifying process referred to as necroinflammation. But how does renal cell necrosis trigger inflammation? Here, we discuss the role of danger-associated molecular patterns (DAMPs), mitochondrial (mito)-DAMPs, and alarmins, as well as their respective pattern recognition receptors. The capacity of DAMPs and alarmins to trigger cytokine and chemokine release initiates the recruitment of leukocytes into the kidney that further amplify necroinflammation. Infiltrating neutrophils often undergo neutrophil extracellular trap formation associated with neutrophil death or necroptosis, which implies a release of histones, which act not only as DAMPs but also elicit direct cytotoxic effects on renal cells, namely endothelial cells. Proinflammatory macrophages and eventually cytotoxic T cells further drive kidney cell death and inflammation. Dissecting the molecular mechanisms of necroinflammation may help to identify the best therapeutic targets to limit nephron loss in kidney injury. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Ayanin diacetate-induced cell death is amplified by TRAIL in human leukemia cells

    Energy Technology Data Exchange (ETDEWEB)

    Marrero, Maria Teresa; Estevez, Sara; Negrin, Gledy; Quintana, Jose [Departamento de Bioquimica, Unidad Asociada al Consejo Superior de Investigaciones Cientificas, Universidad de Las Palmas de Gran Canaria, Plaza Dr. Pasteur s/n, 35016 Las Palmas de Gran Canaria (Spain); Lopez, Mariana; Perez, Francisco J.; Triana, Jorge [Departamento de Quimica, Universidad de Las Palmas de Gran Canaria, Instituto Canario de Investigacion del Cancer, 35017 Las Palmas de Gran Canaria (Spain); Leon, Francisco [Instituto de Productos Naturales y Agrobiologia, Consejo Superior de Investigaciones Cientificas, Avda. Astrofisico F. Sanchez 3, 38206 La Laguna, Tenerife (Spain); Estevez, Francisco, E-mail: festevez@dbbf.ulpgc.es [Departamento de Bioquimica, Unidad Asociada al Consejo Superior de Investigaciones Cientificas, Universidad de Las Palmas de Gran Canaria, Plaza Dr. Pasteur s/n, 35016 Las Palmas de Gran Canaria (Spain)

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer Ayanin diacetate as apoptotic inducer in leukemia cells. Black-Right-Pointing-Pointer Cell death was prevented by caspase inhibitors and by the overexpression of Bcl-x{sub L}. Black-Right-Pointing-Pointer The intrinsic and the extrinsic pathways are involved in the mechanism of action. Black-Right-Pointing-Pointer Death receptors are up-regulated and TRAIL enhances apoptotic cell death. -- Abstract: Here we demonstrate that the semi-synthetic flavonoid ayanin diacetate induces cell death selectively in leukemia cells without affecting the proliferation of normal lymphocytes. Incubation of human leukemia cells with ayanin diacetate induced G{sub 2}-M phase cell cycle arrest and apoptosis which was prevented by the non-specific caspase inhibitor z-VAD-fmk and reduced by the overexpression of Bcl-x{sub L}. Ayanin diacetate-induced cell death was found to be associated with: (i) loss of inner mitochondrial membrane potential, (ii) the release of cytochrome c, (iii) the activation of multiple caspases, (iv) cleavage of poly(ADP-ribose) polymerase and (v) the up-regulation of death receptors for TRAIL, DR4 and DR5. Moreover, the combined treatment with ayanin diacetate and TRAIL amplified cell death, compared to single treatments. These results provide a basis for further exploring the potential applications of this combination for the treatment of cancer.

  10. Extracellular ATP regulates cell death of lymphocytes and monocytes induced by membrane-bound lipoproteins of Mycoplasma fermentans and Mycoplasma salivarium.

    Science.gov (United States)

    Into, Takeshi; Okada, Kazutaka; Inoue, Nobuo; Yasuda, Motoaki; Shibata, Ken-ichiro

    2002-01-01

    The cytotoxicities of lipoproteins of Mycoplasma fermentans and Mycoplasma salivarium to a lymphocytic cell line, MOLT-4, and a monocytic cell line, HL-60, was upregulated by ATP added extracellularly in a dose-dependent manner. These lipoproteins induced ATP release and plasma membrane permeability increase in these cell lines. In addition, periodate-oxidized ATP, an antagonist for P2X purinergic receptors, suppressed the cytotoxicity of the lipoproteins, suggesting the possibility that P2X receptors for ATP play crucial roles in the cytotoxicity. Activation of caspase-3 induced by the lipoproteins, which was assessed by the cleavage of the synthetic substrate DEVD-pNA and the endogenous substrate poly(ADP-ribose) polymerase, was also upregulated and downregulated by extracellular ATP and periodate-oxidized ATP, respectively. On the basis of these results, this study suggests that mycoplasmal lipoproteins induce the permeability increase in lymphocytes and monocytes, by which ATP is released, and the ATP regulates the cytotoxicities of the lipoproteins to the cells, possibly by interaction with ATP receptors such as P2X purinergic receptors.

  11. Increasing RpoS expression causes cell death in Borrelia burgdorferi.

    Directory of Open Access Journals (Sweden)

    Linxu Chen

    Full Text Available RpoS, one of the two alternative σ factors in Borrelia burgdorferi, is tightly controlled by multiple regulators and, in turn, determines expression of many critical virulence factors. Here we show that increasing RpoS expression causes cell death. The immediate effect of increasing RpoS expression was to promote bacterial division and as a consequence result in a rapid increase in cell number before causing bacterial death. No DNA fragmentation or degradation was observed during this induced cell death. Cryo-electron microscopy showed induced cells first formed blebs, which were eventually released from dying cells. Apparently blebbing initiated cell disintegration leading to cell death. These findings led us to hypothesize that increasing RpoS expression triggers intracellular programs and/or pathways that cause spirochete death. The potential biological significance of induced cell death may help B. burgdorferi regulate its population to maintain its life cycle in nature.

  12. Steroid hormone control of cell death and cell survival: molecular insights using RNAi.

    Directory of Open Access Journals (Sweden)

    Suganthi Chittaranjan

    2009-02-01

    Full Text Available The insect steroid hormone ecdysone triggers programmed cell death of obsolete larval tissues during metamorphosis and provides a model system for understanding steroid hormone control of cell death and cell survival. Previous genome-wide expression studies of Drosophila larval salivary glands resulted in the identification of many genes associated with ecdysone-induced cell death and cell survival, but functional verification was lacking. In this study, we test functionally 460 of these genes using RNA interference in ecdysone-treated Drosophila l(2mbn cells. Cell viability, cell morphology, cell proliferation, and apoptosis assays confirmed the effects of known genes and additionally resulted in the identification of six new pro-death related genes, including sorting nexin-like gene SH3PX1 and Sox box protein Sox14, and 18 new pro-survival genes. Identified genes were further characterized to determine their ecdysone dependency and potential function in cell death regulation. We found that the pro-survival function of five genes (Ras85D, Cp1, CG13784, CG32016, and CG33087, was dependent on ecdysone signaling. The TUNEL assay revealed an additional two genes (Kap-alpha3 and Smr with an ecdysone-dependent cell survival function that was associated with reduced cell death. In vitro, Sox14 RNAi reduced the percentage of TUNEL-positive l(2mbn cells (p<0.05 following ecdysone treatment, and Sox14 overexpression was sufficient to induce apoptosis. In vivo analyses of Sox14-RNAi animals revealed multiple phenotypes characteristic of aberrant or reduced ecdysone signaling, including defects in larval midgut and salivary gland destruction. These studies identify Sox14 as a positive regulator of ecdysone-mediated cell death and provide new insights into the molecular mechanisms underlying the ecdysone signaling network governing cell death and cell survival.

  13. Cell survival, cell death and cell cycle pathways are interconnected: Implications for cancer therapy

    DEFF Research Database (Denmark)

    Maddika, S; Ande, SR; Panigrahi, S

    2007-01-01

    both for their apoptosis-regulating capacity and also for their effect on the cell cycle progression. The PI3-K/Akt cell survival pathway is shown as regulator of cell metabolism and cell survival, but examples are also provided where aberrant activity of the pathway may contribute to the induction......The partial cross-utilization of molecules and pathways involved in opposing processes like cell survival, proliferation and cell death, assures that mutations within one signaling cascade will also affect the other opposite process at least to some extent, thus contributing to homeostatic...... regulatory circuits. This review highlights some of the connections between opposite-acting pathways. Thus, we discuss the role of cyclins in the apoptotic process, and in the regulation of cell proliferation. CDKs and their inhibitors like the INK4-family (p16(Ink4a), p15(Ink4b), p18(Ink4c), p19(Ink4d...

  14. Inducible cell death in plant immunity

    DEFF Research Database (Denmark)

    Hofius, Daniel; Tsitsigiannis, Dimitrios I; Jones, Jonathan D G

    2006-01-01

    Programmed cell death (PCD) occurs during vegetative and reproductive plant growth, as typified by autumnal leaf senescence and the terminal differentiation of the endosperm of cereals which provide our major source of food. PCD also occurs in response to environmental stress and pathogen attack......, and these inducible PCD forms are intensively studied due their experimental tractability. In general, evidence exists for plant cell death pathways which have similarities to the apoptotic, autophagic and necrotic forms described in yeast and metazoans. Recent research aiming to understand these pathways...

  15. ETosis: A Microbicidal Mechanism beyond Cell Death

    Directory of Open Access Journals (Sweden)

    Anderson B. Guimarães-Costa

    2012-01-01

    Full Text Available Netosis is a recently described type of neutrophil death occurring with the release to the extracellular milieu of a lattice composed of DNA associated with histones and granular and cytoplasmic proteins. These webs, initially named neutrophil extracellular traps (NETs, ensnare and kill microorganisms. Similarly, other cell types, such as eosinophils, mast cells, and macrophages, can also dye by this mechanism; thus, it was renamed as ETosis, meaning death with release of extracellular traps (ETs. Here, we review the mechanism of NETosis/etosis, emphasizing its role in diseases caused by protozoan parasites, fungi, and viruses.

  16. Viral-induced systemic necrosis in plants involves both programmed cell death and the inhibition of viral multiplication, which are regulated by independent pathways.

    Science.gov (United States)

    Komatsu, Ken; Hashimoto, Masayoshi; Ozeki, Johji; Yamaji, Yasuyuki; Maejima, Kensaku; Senshu, Hiroko; Himeno, Misako; Okano, Yukari; Kagiwada, Satoshi; Namba, Shigetou

    2010-03-01

    Resistant plants respond rapidly to invading avirulent plant viruses by triggering a hypersensitive response (HR). An HR is accompanied by a restraint of virus multiplication and programmed cell death (PCD), both of which have been observed in systemic necrosis triggered by a successful viral infection. Here, we analyzed signaling pathways underlying the HR in resistance genotype plants and those leading to systemic necrosis. We show that systemic necrosis in Nicotiana benthamiana, induced by Plantago asiatica mosaic virus (PlAMV) infection, was associated with PCD, biochemical features, and gene expression patterns that are characteristic of HR. The induction of necrosis caused by PlAMV infection was dependent on SGT1, RAR1, and the downstream mitogen-activated protein kinase (MAPK) cascade involving MAPKKKalpha and MEK2. However, although SGT1 and RAR1 silencing led to an increased accumulation of PlAMV, silencing of the MAPKKKalpha-MEK2 cascade did not. This observation indicates that viral multiplication is partly restrained even in systemic necrosis induced by viral infection, and that this restraint requires SGT1 and RAR1 but not the MAPKKKalpha-MEK2 cascade. Similarly, although both SGT1 and MAPKKKalpha were essential for the Rx-mediated HR to Potato virus X (PVX), SGT1 but not MAPKKKalpha was involved in the restraint of PVX multiplication. These results suggest that systemic necrosis and HR consist of PCD and a restraint of virus multiplication, and that the latter is induced through unknown pathways independent from the former.

  17. Cobalt alleviates GA-induced programmed cell death in wheat aleurone layers via the regulation of H2O2 production and heme oxygenase-1 expression.

    Science.gov (United States)

    Wu, Mingzhu; Li, Jiale; Wang, Fangquan; Li, Feng; Yang, Jun; Shen, Wenbiao

    2014-11-14

    Heme oxygenase-1 (HO-1) and hydrogen peroxide (H2O2) are key signaling molecules that are produced in response to various environmental stimuli. Here, we demonstrate that cobalt is able to delay gibberellic acid (GA)-induced programmed cell death (PCD) in wheat aleurone layers. A similar response was observed when samples were pretreated with carbon monoxide (CO) or bilirubin (BR), two end-products of HO catalysis. We further observed that increased HO-1 expression played a role in the cobalt-induced alleviation of PCD. The application of HO-1-specific inhibitor, zinc protoporphyrin-IX (ZnPPIX), substantially prevented the increases of HO-1 activity and the alleviation of PCD triggered by cobalt. The stimulation of HO-1 expression, and alleviation of PCD might be caused by the initial H2O2 production induced by cobalt. qRT-PCR and enzymatic assays revealed that cobalt-induced gene expression and the corresponding activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), three enzymes that metabolize reactive oxygen species, were consistent with the H2O2 accumulation during GA treatment. These cobalt responses were differentially blocked by co-treatment with ZnPPIX. We therefore suggest that HO-1 functions in the cobalt-triggered alleviation of PCD in wheat aleurone layers, which is also dependent on the enhancement of the activities of antioxidant enzymes.

  18. Plant programmed cell death from a chromatin point of view.

    Science.gov (United States)

    Latrasse, D; Benhamed, M; Bergounioux, C; Raynaud, C; Delarue, M

    2016-10-01

    Programmed cell death (PCD) is a ubiquitous genetically regulated process consisting of the activation of finely controlled signalling pathways that lead to cellular suicide. PCD can be part of a developmental programme (dPCD) or be triggered by environmental conditions (ePCD). In plant cells, as in animal cells, extensive chromatin condensation and degradation of the nuclear DNA are among the most conspicuous features of cells undergoing PCD. Changes in chromatin condensation could either reflect the structural changes required for internucleosomal fragmentation of nuclear DNA or relate to large-scale chromatin rearrangements associated with a major transcriptional switch occurring during cell death. The aim of this review is to give an update on plant PCD processes from a chromatin point of view. The first part will be dedicated to chromatin conformational changes associated with cell death observed in various developmental and physiological conditions, whereas the second part will be devoted to histone dynamics and DNA modifications associated with critical changes in genome expression during the cell death process. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  19. Augmented cell death with Bloom syndrome helicase deficiency.

    Science.gov (United States)

    Kaneko, Hideo; Fukao, Toshiyuki; Kasahara, Kimiko; Yamada, Taketo; Kondo, Naomi

    2011-01-01

    Bloom syndrome (BS) is a rare autosomal genetic disorder characterized by lupus-like erythematous telangi-ectasias of the face, sun sensitivity, infertility, stunted growth, upper respiratory infection, and gastrointestinal infections commonly associated with decreased immuno-globulin levels. The syndrome is associated with immuno-deficiency of a generalized type, ranging from mild and essentially asympto-matic to severe. Chromosomal abnormalities are hallmarks of the disorder, and high frequencies of sister chromatid exchanges and quadriradial configurations in lymphocytes and fibroblasts are diagnostic features. BS is caused by mutations in BLM, a member of the RecQ helicase family. We determined whether BLM deficiency has any effects on cell growth and death in BLM-deficient cells and mice. BLM-deficient EB-virus-transformed cell lines from BS patients and embryonic fibroblasts from BLM-/- mice showed slower growth than wild-type cells. BLM-deficient cells showed abnormal p53 protein expression after irradiation. In BLM-/- mice, small body size, reduced number of fetal liver cells and increased cell death were observed. BLM deficiency causes the up-regulation of p53, double-strand break and apoptosis, which are likely observed in irradiated control cells. Slow cell growth and increased cell death may be one of the causes of the small body size associated with BS patients.

  20. Lipid raft involvement in yeast cell growth and death

    Directory of Open Access Journals (Sweden)

    Faustino eMollinedo

    2012-10-01

    Full Text Available The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Crytococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na+, K+ and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  1. Morphological classification of plant cell deaths

    NARCIS (Netherlands)

    Doorn, van W.G.; Beers, E.P.; Dangl, J.L.; Franklin-Tong, V.E.; Woltering, E.J.

    2011-01-01

    Programmed cell death (PCD) is an integral part of plant development and of responses to abiotic stress or pathogens. Although the morphology of plant PCD is, in some cases, well characterised and molecular mechanisms controlling plant PCD are beginning to emerge, there is still confusion about the

  2. Optical imaging of cancer and cell death

    NARCIS (Netherlands)

    Xie, Bangwen

    2013-01-01

    The aim of the work included in this PhD thesis was to explore the diverse application possibility of using NIR fluorescent probes with specific properties to visualize and characterize cancer and cell death. In this thesis, we mainly focus on optical imaging and its application, both at microscopic

  3. Translocation of p53 to Mitochondria Is Regulated by Its Lipid Binding Property to Anionic Phospholipids and It Participates in Cell Death Control

    Directory of Open Access Journals (Sweden)

    Ching-Hao Li

    2010-02-01

    Full Text Available p53, can regulate cell apoptosis in both transcription-dependent and -independent manners. The transcription-independent pathway was demonstrated by the translocation of p53 to mitochondria. Our study showed that p53 mitochondrial translocation was found in mitomycin C (MMC-treated HepG2. The p53 C-terminal domain is clustered with potential nuclear leading sequences and showed strong electrostatic ion-ion interactions with cardiolipin, phosphatidylglycerol and phosphatidic acid in vitro. Disruption of cardiolipin biosynthesis by phosphatidylglycero-phosphate synthase (PGS or CDP-diacylglycerol synthase 2 (CDS-2 short hairpin RNA (shRNA transfection eliminated the MMC-induced translocation of mitochondrial p53. The elimination of mitochondrial p53 translocation also reduced Bcl-xL and Bcl-2 mitochondrial distribution. In HEK 293T models with saturated p53 expression, the mitochondrial partition of p53, Bcl-xL, and Bcl-2 obviously decreased in their PGS shRNA- or CDS-2 shRNA-expressing stable clones. In p53-null H1299 models, both the mitochondrial partitions of Bcl-xL and Bcl-2 were strongly reduced in relation to the HEK 293T models. The Bcl-xL mitochondrial partition was elevated in H1299 models expressing pCEP4-p53wt suggesting the direct carrier role of p53 in transporting Bcl-xL to the mitochondria. We also found that the cytosolic pool of Bcl-xL and Bcl-2 remained unaffected in the low-dose MMC treatment but decreased in the high-dose MMC treatment. The cytosolic pool of Bcl-2 and Bcl-xL directly regulated their amounts in p53-dependent mitochondrial distribution. In the low-dose MMC treatment, the increased mitochondrial p53, Bcl-xL, and Bcl-2 could attenuate apoptosis. However, in the high-dose MMC treatment, only the p53 translocated to the mitochondria and resulted in apoptosis progression. On the basis of this study, we thought mitochondrial p53 might regulate apoptosis in a biphasic manner.

  4. Non-apoptotic cell death in animal development.

    Science.gov (United States)

    Kutscher, Lena M; Shaham, Shai

    2017-08-01

    Programmed cell death (PCD) is an important process in the development of multicellular organisms. Apoptosis, a form of PCD characterized morphologically by chromatin condensation, membrane blebbing, and cytoplasm compaction, and molecularly by the activation of caspase proteases, has been extensively investigated. Studies in Caenorhabditis elegans, Drosophila, mice, and the developing chick have revealed, however, that developmental PCD also occurs through other mechanisms, morphologically and molecularly distinct from apoptosis. Some non-apoptotic PCD pathways, including those regulating germ cell death in Drosophila, still appear to employ caspases. However, another prominent cell death program, linker cell-type death (LCD), is morphologically conserved, and independent of the key genes that drive apoptosis, functioning, at least in part, through the ubiquitin proteasome system. These non-apoptotic processes may serve as backup programs when caspases are inactivated or unavailable, or, more likely, as freestanding cell culling programs. Non-apoptotic PCD has been documented extensively in the developing nervous system, and during the formation of germline and somatic gonadal structures, suggesting that preservation of these mechanisms is likely under strong selective pressure. Here, we discuss our current understanding of non-apoptotic PCD in animal development, and explore possible roles for LCD and other non-apoptotic developmental pathways in vertebrates. We raise the possibility that during vertebrate development, apoptosis may not be the major PCD mechanism.

  5. Programmed cell death during quinoa perisperm development.

    Science.gov (United States)

    López-Fernández, María Paula; Maldonado, Sara

    2013-08-01

    At seed maturity, quinoa (Chenopodium quinoa Willd.) perisperm consists of uniform, non-living, thin-walled cells full of starch grains. The objective of the present study was to study quinoa perisperm development and describe the programme of cell death that affects the entire tissue. A number of parameters typically measured during programmed cell death (PCD), such as cellular morphological changes in nuclei and cytoplasm, endoreduplication, DNA fragmentation, and the participation of nucleases and caspase-like proteases in nucleus dismantling, were evaluated; morphological changes in cytoplasm included subcellular aspects related to starch accumulation. This study proved that, following fertilization, the perisperm of quinoa simultaneously accumulates storage reserves and degenerates, both processes mediated by a programme of developmentally controlled cell death. The novel findings regarding perisperm development provide a starting point for further research in the Amaranthaceae genera, such as comparing seeds with and without perisperm, and specifying phylogeny and evolution within this taxon. Wherever possible and appropriate, differences between quinoa perisperm and grass starchy endosperm--a morphologically and functionally similar, although genetically different tissue--were highlighted and discussed.

  6. Optical imaging of cancer and cell death

    OpenAIRE

    Xie, Bangwen

    2013-01-01

    The aim of the work included in this PhD thesis was to explore the diverse application possibility of using NIR fluorescent probes with specific properties to visualize and characterize cancer and cell death. In this thesis, we mainly focus on optical imaging and its application, both at microscopic and macroscopic level. Because we believe optical imaging in particular represents a technology that has unique potential to exploit further our knowledge in preclinical research. First, we imaged...

  7. A High-Throughput Small Molecule Screen for C. elegans Linker Cell Death Inhibitors.

    Science.gov (United States)

    Schwendeman, Andrew R; Shaham, Shai

    2016-01-01

    Programmed cell death is a ubiquitous process in metazoan development. Apoptosis, one cell death form, has been studied extensively. However, mutations inactivating key mammalian apoptosis regulators do not block most developmental cell culling, suggesting that other cell death pathways are likely important. Recent work in the nematode Caenorhabditis elegans identified a non-apoptotic cell death form mediating the demise of the male-specific linker cell. This cell death process (LCD, linker cell-type death) is morphologically conserved, and its molecular effectors also mediate axon degeneration in mammals and Drosophila. To develop reagents to manipulate LCD, we established a simple high-throughput screening protocol for interrogating the effects of small molecules on C. elegans linker cell death in vivo. From 23,797 compounds assayed, 11 reproducibly block linker cell death onset. Of these, five induce animal lethality, and six promote a reversible developmental delay. These results provide proof-of principle validation of our screening protocol, demonstrate that developmental progression is required for linker cell death, and suggest that larger scale screens may identify LCD-specific small-molecule regulators that target the LCD execution machinery.

  8. Conserved metabolic energy production pathways govern Eiger/TNF-induced nonapoptotic cell death.

    Science.gov (United States)

    Kanda, Hiroshi; Igaki, Tatsushi; Okano, Hideyuki; Miura, Masayuki

    2011-11-22

    Caspase-independent cell death is known to be important in physiological and pathological conditions, but its molecular regulation is not well-understood. Eiger is the sole fly ortholog of TNF. The ectopic expression of Eiger in the developing eye primordium caused JNK-dependent but caspase-independent cell death. To understand the molecular basis of this Eiger-induced nonapoptotic cell death, we performed a large-scale genetic screen in Drosophila for suppressors of the Eiger-induced cell death phenotype. We found that molecules that regulate metabolic energy production are central to this form of cell death: it was dramatically suppressed by decreased levels of molecules that regulate cytosolic glycolysis, mitochondrial β-oxidation of fatty acids, the tricarboxylic acid cycle, and the electron transport chain. Importantly, reducing the expression of energy production-related genes did not affect the cell death triggered by proapoptotic genes, such as reaper, hid, or debcl, indicating that the energy production-related genes have a specific role in Eiger-induced nonapoptotic cell death. We also found that energy production-related genes regulate the Eiger-induced cell death downstream of JNK. In addition, Eiger induced the production of reactive oxygen species in a manner dependent on energy production-related genes. Furthermore, we showed that this cell death machinery is involved in Eiger's physiological function, because decreasing the energy production-related genes suppressed Eiger-dependent tumor suppression, an intrinsic mechanism for removing tumorigenic mutant clones from epithelia by inducing cell death. This result suggests a link between sensitivity to cell death and metabolic activity in cancer.

  9. C. elegans EIF-3.K promotes programmed cell death through CED-3 caspase.

    Directory of Open Access Journals (Sweden)

    Chun-Yi Huang

    Full Text Available Programmed cell death (apoptosis is essential for the development and homeostasis of metazoans. The central step in the execution of programmed cell death is the activation of caspases. In C. elegans, the core cell death regulators EGL-1(a BH3 domain-containing protein, CED-9 (Bcl-2, and CED-4 (Apaf-1 act in an inhibitory cascade to activate the CED-3 caspase. Here we have identified an additional component eif-3.K (eukaryotic translation initiation factor 3 subunit k that acts upstream of ced-3 to promote programmed cell death. The loss of eif-3.K reduced cell deaths in both somatic and germ cells, whereas the overexpression of eif-3.K resulted in a slight but significant increase in cell death. Using a cell-specific promoter, we show that eif-3.K promotes cell death in a cell-autonomous manner. In addition, the loss of eif-3.K significantly suppressed cell death-induced through the overexpression of ced-4, but not ced-3, indicating a distinct requirement for eif-3.K in apoptosis. Reciprocally, a loss of ced-3 suppressed cell death induced by the overexpression of eif-3.K. These results indicate that eif-3.K requires ced-3 to promote programmed cell death and that eif-3.K acts upstream of ced-3 to promote this process. The EIF-3.K protein is ubiquitously expressed in embryos and larvae and localizes to the cytoplasm. A structure-function analysis revealed that the 61 amino acid long WH domain of EIF-3.K, potentially involved in protein-DNA/RNA interactions, is both necessary and sufficient for the cell death-promoting activity of EIF-3.K. Because human eIF3k was able to partially substitute for C. elegans eif-3.K in the promotion of cell death, this WH domain-dependent EIF-3.K-mediated cell death process has potentially been conserved throughout evolution.

  10. Cell Death in Chondrocytes, Osteoblasts, and Osteocytes

    Directory of Open Access Journals (Sweden)

    Toshihisa Komori

    2016-12-01

    Full Text Available Cell death in skeletal component cells, including chondrocytes, osteoblasts, and osteocytes, plays roles in skeletal development, maintenance, and repair as well as in the pathogenesis of osteoarthritis and osteoporosis. Chondrocyte proliferation, differentiation, and apoptosis are important steps for endochondral ossification. Although the inactivation of P53 and RB is involved in the pathogenesis of osteosarcomas, the deletion of p53 and inactivation of Rb are insufficient to enhance chondrocyte proliferation, indicating the presence of multiple inhibitory mechanisms against sarcomagenesis in chondrocytes. The inflammatory processes induced by mechanical injury and chondrocyte death through the release of danger-associated molecular patterns (DAMPs are involved in the pathogenesis of posttraumatic osteoarthritis. The overexpression of BCLXL increases bone volume with a normal structure and maintains bone during aging by inhibiting osteoblast apoptosis. p53 inhibits osteoblast proliferation and enhances osteoblast apoptosis, thereby reducing bone formation, but also exerts positive effects on osteoblast differentiation through the Akt–FoxOs pathway. Apoptotic osteocytes release ATP, which induces the receptor activator of nuclear factor κ-B ligand (Rankl expression and osteoclastogenesis, from pannexin 1 channels. Osteocyte death ultimately results in necrosis; DAMPs are released to the bone surface and promote the production of proinflammatory cytokines, which induce Rankl expression, and osteoclastogenesis is further enhanced.

  11. In vitro and in vivo study of endothelial cells radio-induced death modulation by Sphingosine-1-Phosphate; Etude in vitro et in vivo de la regulation de la mort radioinduite des cellules endotheliales par la Sphingosine-1-Phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Bonnaud, St

    2007-01-15

    Protecting the vasculature from radiation-induced death is a major concern in tissue radioprotection. Developing a model of endothelial cells radiosensitivity, we proved that HMEC-1 undergo 2 waves of death after exposure to 15 Gy: an early pre mitotic apoptosis dependent of ceramide generation and a delayed DNA damage-induced mitotic death. Sphingosine-1-Phosphate (S1P), a ceramide antagonist, protects HMEC-1 only from early apoptosis, but not from mitotic death. We confirmed in vivo the S1P radioprotection from ceramide-mediated radio-induced apoptosis, and that S1P radioprotection is partially mediated by S1Ps receptors. Segregation between these 2 types of death may give the opportunity to define a new class of radioprotectors for normal tissue where quiescent endothelium represent the most sensitive target, while excluding malignant tumor containing pro-proliferating angiogenic endothelial cells, sensitive to mitotic death. (author)

  12. Colorectal Cancer Stem Cells and Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Catalano, Veronica [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Gaggianesi, Miriam [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Department of Cellular and Molecular Oncology, IRCCS Fondazione Salvatore Maugeri, Via Salvatore Maugeri, 27100 Pavia, PV (Italy); Spina, Valentina; Iovino, Flora [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Dieli, Francesco [Departement of Biopathology and Medicine Biotechnologies, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Stassi, Giorgio, E-mail: giorgio.stassi@unipa.it [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy); Department of Cellular and Molecular Oncology, IRCCS Fondazione Salvatore Maugeri, Via Salvatore Maugeri, 27100 Pavia, PV (Italy); Todaro, Matilde [Department of Surgical and Oncological Sciences, University of Palermo, Via Liborio Giuffrè 5, 90127 Palermo, PA (Italy)

    2011-04-11

    Nowadays it is reported that, similarly to other solid tumors, colorectal cancer is sustained by a rare subset of cancer stem–like cells (CSCs), which survive conventional anticancer treatments, thanks to efficient mechanisms allowing escape from apoptosis, triggering tumor recurrence. To improve patient outcomes, conventional anticancer therapies have to be replaced with specific approaches targeting CSCs. In this review we provide strong support that BMP4 is an innovative therapeutic approach to prevent colon cancer growth increasing differentiation markers expression and apoptosis. Recent data suggest that in colorectal CSCs, protection from apoptosis is achieved by interleukin-4 (IL-4) autocrine production through upregulation of antiapoptotic mediators, including survivin. Consequently, IL-4 neutralization could deregulate survivin expression and localization inducing chemosensitivity of the colon CSCs pool.

  13. NCAM regulates cell motility

    DEFF Research Database (Denmark)

    Prag, Søren; Lepekhin, Eugene A; Kolkova, Kateryna

    2002-01-01

    Cell migration is required during development of the nervous system. The regulatory mechanisms for this process, however, are poorly elucidated. We show here that expression of or exposure to the neural cell adhesion molecule (NCAM) strongly affected the motile behaviour of glioma cells...... independently of homophilic NCAM interactions. Expression of the transmembrane 140 kDa isoform of NCAM (NCAM-140) caused a significant reduction in cellular motility, probably through interference with factors regulating cellular attachment, as NCAM-140-expressing cells exhibited a decreased attachment...... to a fibronectin substratum compared with NCAM-negative cells. Ectopic expression of the cytoplasmic part of NCAM-140 also inhibited cell motility, presumably via the non-receptor tyrosine kinase p59(fyn) with which NCAM-140 interacts. Furthermore, we showed that the extracellular part of NCAM acted as a paracrine...

  14. Determinative developmental cell lineages are robust to cell deaths.

    Directory of Open Access Journals (Sweden)

    Jian-Rong Yang

    2014-07-01

    Full Text Available All forms of life are confronted with environmental and genetic perturbations, making phenotypic robustness an important characteristic of life. Although development has long been viewed as a key component of phenotypic robustness, the underlying mechanism is unclear. Here we report that the determinative developmental cell lineages of two protostomes and one deuterostome are structured such that the resulting cellular compositions of the organisms are only modestly affected by cell deaths. Several features of the cell lineages, including their shallowness, topology, early ontogenic appearances of rare cells, and non-clonality of most cell types, underlie the robustness. Simple simulations of cell lineage evolution demonstrate the possibility that the observed robustness arose as an adaptation in the face of random cell deaths in development. These results reveal general organizing principles of determinative developmental cell lineages and a conceptually new mechanism of phenotypic robustness, both of which have important implications for development and evolution.

  15. N-Desmethyldauricine Induces Autophagic Cell Death in Apoptosis-Defective Cells via Ca(2+) Mobilization.

    Science.gov (United States)

    Law, Betty Y K; Mok, Simon W F; Chen, Juan; Michelangeli, Francesco; Jiang, Zhi-Hong; Han, Yu; Qu, Yuan Q; Qiu, Alena C L; Xu, Su-Wei; Xue, Wei-Wei; Yao, Xiao-Jun; Gao, Jia Y; Javed, Masood-Ul-Hassan; Coghi, Paolo; Liu, Liang; Wong, Vincent K W

    2017-01-01

    Resistance of cancer cells to chemotherapy remains a significant problem in oncology. Mechanisms regulating programmed cell death, including apoptosis, autophagy or necrosis, in the treatment of cancers have been extensively investigated over the last few decades. Autophagy is now emerging as an important pathway in regulating cell death or survival in cancer therapy. Recent studies demonstrated variety of natural small-molecules could induce autophagic cell death in apoptosis-resistant cancer cells, therefore, discovery of novel autophagic enhancers from natural products could be a promising strategy for treatment of chemotherapy-resistant cancer. By computational virtual docking analysis, biochemical assays, and advanced live-cell imaging techniques, we have identified N-desmethyldauricine (LP-4), isolated from rhizoma of Menispermum dauricum DC as a novel inducer of autophagy. LP-4 was shown to induce autophagy via the Ulk-1-PERK and Ca(2+)/Calmodulin-dependent protein kinase kinase β (CaMKKβ)-AMPK-mTOR signaling cascades, via mobilizing calcium release through inhibition of SERCA, and importantly, lead to autophagic cell death in a panel of cancer cells, apoptosis-defective and apoptosis-resistant cells. Taken together, this study provides detailed insights into the cytotoxic mechanism of a novel autophagic compound that targeting the apoptosis resistant cancer cells, and new implication on drug discovery from natural products for drug resistant cancer therapy.

  16. Programmed cell death in plants and caspase-like activities

    NARCIS (Netherlands)

    Gaussand, Gwénael Martial Daniel Jean-Marie

    2007-01-01

    The development of multicellular organisms involves an important balance between cell growth, cell division and cell death. In animals, programmed cell death (PCD) plays a key role by forming and deleting structures, controlling cell numbers and eliminating abnormal damaged cells. Caspases were

  17. Autophagic cell death: Loch Ness monster or endangered species?

    Science.gov (United States)

    Shen, Han-Ming; Codogno, Patrice

    2011-05-01

    The concept of autophagic cell death was first established based on observations of increased autophagic markers in dying cells. The major limitation of such a morphology-based definition of autophagic cell death is that it fails to establish the functional role of autophagy in the cell death process, and thus contributes to the confusion in the literature regarding the role of autophagy in cell death and cell survival. Here we propose to define autophagic cell death as a modality of non-apoptotic or necrotic programmed cell death in which autophagy serves as a cell death mechanism, upon meeting the following set of criteria: (i) cell death occurs without the involvement of apoptosis; (ii) there is an increase of autophagic flux, and not just an increase of the autophagic markers, in the dying cells; and (iii) suppression of autophagy via both pharmacological inhibitors and genetic approaches is able to rescue or prevent cell death. In light of this new definition, we will discuss some of the common problems and difficulties in the study of autophagic cell death and also revisit some well-reported cases of autophagic cell death, aiming to achieve a better understanding of whether autophagy is a real killer, an accomplice or just an innocent bystander in the course of cell death. At present, the physiological relevance of autophagic cell death is mainly observed in lower eukaryotes and invertebrates such as Dictyostelium discoideum and Drosophila melanogaster. We believe that such a clear definition of autophagic cell death will help us study and understand the physiological or pathological relevance of autophagic cell death in mammals.

  18. Comparison of Types of Cell Death: Apoptosis and Necrosis.

    Science.gov (United States)

    Manning, Francis; Zuzel, Katherine

    2003-01-01

    Cell death is an essential factor in many biological processes including development. Discusses two types of cell death: (1) necrosis (induced by sodium azide); and (2) apoptosis (induced by sodium chromate). Illustrates key features that differ between these two types of cells death including loss of membrane integrity and internucleosomal DNA…

  19. Melting Behaviour of Cell Death Lipids

    Science.gov (United States)

    Leung, Sherry; Sot, Jesus; Goni, Felix; Thewalt, Jenifer

    2009-05-01

    Sphingomyelin is a major lipid constituent of mammalian cell plasma membranes. It is converted into ceramide during programmed cell death. It is hypothesized that this conversion induces a structural change in membranes that is responsible for downstream signaling. To characterize these structural changes, deuterium nuclear magnetic resonance spectroscopy is used to create a concentration-temperature phase diagram of palmitoyl sphingomyelin:ceramide multilamellar vesicles in excess water between 0-40 mol% ceramide and 25-80^oC. The two lipids are fully miscible at high temperatures and at 40 mol% ceramide. A variety of solid-liquid coexistence phase behavior is observed at lower concentrations. With increasing ceramide content, a gel phase is observed at progressively higher temperatures, implying that at physiological temperature, ceramide may increase the gel phase propensity of cell membranes.

  20. Antioxidant gene therapy against neuronal cell death

    Science.gov (United States)

    Navarro-Yepes, Juliana; Zavala-Flores, Laura; Annadurai, Anandhan; Wang, Fang; Skotak, Maciej; Chandra, Namas; Li, Ming; Pappa, Aglaia; Martinez-Fong, Daniel; Razo, Luz Maria Del; Quintanilla-Vega, Betzabet; Franco, Rodrigo

    2014-01-01

    Oxidative stress is a common hallmark of neuronal cell death associated with neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, as well as brain stroke/ischemia and traumatic brain injury. Increased accumulation of reactive species of both oxygen (ROS) and nitrogen (RNS) has been implicated in mitochondrial dysfunction, energy impairment, alterations in metal homeostasis and accumulation of aggregated proteins observed in neurodegenerative disorders, which lead to the activation/modulation of cell death mechanisms that include apoptotic, necrotic and autophagic pathways. Thus, the design of novel antioxidant strategies to selectively target oxidative stress and redox imbalance might represent important therapeutic approaches against neurological disorders. This work reviews the evidence demonstrating the ability of genetically encoded antioxidant systems to selectively counteract neuronal cell loss in neurodegenerative diseases and ischemic brain damage. Because gene therapy approaches to treat inherited and acquired disorders offer many unique advantages over conventional therapeutic approaches, we discussed basic research/clinical evidence and the potential of virus-mediated gene delivery techniques for antioxidant gene therapy. PMID:24333264

  1. Natural Compounds As Modulators of Non-apoptotic Cell Death in Cancer Cells.

    Science.gov (United States)

    Guamán-Ortiz, Luis Miguel; Orellana, Maria Isabel Ramirez; Ratovitski, Edward A

    2017-04-01

    Cell death is an innate capability of cells to be removed from microenvironment, if and when they are damaged by multiple stresses. Cell death is often regulated by multiple molecular pathways and mechanism, including apoptosis, autophagy, and necroptosis. The molecular network underlying these processes is often intertwined and one pathway can dynamically shift to another one acquiring certain protein components, in particular upon treatment with various drugs. The strategy to treat human cancer ultimately relies on the ability of anticancer therapeutics to induce tumor-specific cell death, while leaving normal adjacent cells undamaged. However, tumor cells often develop the resistance to the drug-induced cell death, thus representing a great challenge for the anticancer approaches. Numerous compounds originated from the natural sources and biopharmaceutical industries are applied today in clinics showing advantageous results. However, some exhibit serious toxic side effects. Thus, novel effective therapeutic approaches in treating cancers are continued to be developed. Natural compounds with anticancer activity have gained a great interest among researchers and clinicians alike since they have shown more favorable safety and efficacy then the synthetic marketed drugs. Numerous studies in vitro and in vivo have found that several natural compounds display promising anticancer potentials. This review underlines certain information regarding the role of natural compounds from plants, microorganisms and sea life forms, which are able to induce non-apoptotic cell death in tumor cells, namely autophagy and necroptosis.

  2. Death Receptor-Mediated Cell Death and Proinflammatory Signaling in Nonalcoholic SteatohepatitisSummary

    Directory of Open Access Journals (Sweden)

    Petra Hirsova

    2015-01-01

    Full Text Available Nonalcoholic fatty liver disease (NAFLD is becoming a public health problem worldwide. A subset of patients develop an inflammatory disease, nonalcoholic steatohepatitis (NASH, characterized by steatosis, hepatocellular death, macrophage and neutrophil accumulation, and varying stages of fibrosis. Hepatocyte cell death triggers the cellular inflammatory response, therefore reducing cell death may be salutary in the steatohepatitis disease process. Recently, a better understanding of hepatocyte apoptosis in NASH has been obtained and new information regarding other cell death modes such as necroptosis and pyroptosis has been reported. Hepatocyte lipotoxicity is often triggered by death receptors. In addition to causing apoptosis, death receptors have been shown to mediate proinflammatory signaling, suggesting that apoptosis in this context is not an immunologically silent process. Here, we review recent developments in our understanding of hepatocyte cell death by death receptors and its mechanistic link to inflammation in NASH. We emphasize how proapoptotic signaling by death receptors may induce the release of proinflammatory extracellular vesicles, thereby recruiting and activating macrophages and promoting the steatohepatitis process. Potential therapeutic strategies are discussed based on this evolving information. Keywords: Apoptosis, Caspase Inhibitor, Cell Death, Death Receptors, Exosomes, Extracellular Vesicles, Fibrosis, Inflammation, Inflammasome, Microvesicles, Necroptosis, Pyroptosis

  3. GSK-3: A Bifunctional Role in Cell Death Pathways

    Directory of Open Access Journals (Sweden)

    Keith M. Jacobs

    2012-01-01

    Full Text Available Although glycogen synthase kinase-3 beta (GSK-3β was originally named for its ability to phosphorylate glycogen synthase and regulate glucose metabolism, this multifunctional kinase is presently known to be a key regulator of a wide range of cellular functions. GSK-3β is involved in modulating a variety of functions including cell signaling, growth metabolism, and various transcription factors that determine the survival or death of the organism. Secondary to the role of GSK-3β in various diseases including Alzheimer’s disease, inflammation, diabetes, and cancer, small molecule inhibitors of GSK-3β are gaining significant attention. This paper is primarily focused on addressing the bifunctional or conflicting roles of GSK-3β in both the promotion of cell survival and of apoptosis. GSK-3β has emerged as an important molecular target for drug development.

  4. Prodigiosin activates endoplasmic reticulum stress cell death pathway in human breast carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Mu-Yun [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Shen, Yuh-Chiang [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); National Research Institute of Chinese Medicine, Taipei, Taiwan (China); Lu, Chien-Hsing [Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Obstetrics and Gynecology, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Yang, Shu-Yi [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Ho, Tsing-Fen [Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Peng, Yu-Ta [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chang, Chia-Che, E-mail: chia_che@dragon.nchu.edu.tw [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China)

    2012-12-15

    Prodigiosin is a bacterial tripyrrole pigment with potent cytotoxicity against diverse human cancer cell lines. Endoplasmic reticulum (ER) stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable. In this study, the role of ER stress in prodigiosin-induced cytotoxicity was elucidated for the first time. Comparable to the ER stress inducer thapsigargin, prodigiosin up-regulated signature ER stress markers GRP78 and CHOP in addition to activating the IRE1, PERK and ATF6 branches of the unfolded protein response (UPR) in multiple human breast carcinoma cell lines, confirming prodigiosin as an ER stress inducer. Prodigiosin transcriptionally up-regulated CHOP, as evidenced by its promoting effect on the CHOP promoter activity. Of note, knockdown of CHOP effectively lowered prodigiosin's capacity to evoke PARP cleavage, reduce cell viability and suppress colony formation, highlighting an essential role of CHOP in prodigiosin-induced cytotoxic ER stress response. In addition, prodigiosin down-regulated BCL2 in a CHOP-dependent manner. Importantly, restoration of BCL2 expression blocked prodigiosin-induced PARP cleavage and greatly enhanced the survival of prodigiosin-treated cells, suggesting that CHOP-dependent BCL2 suppression mediates prodigiosin-elicited cell death. Moreover, pharmacological inhibition of JNK by SP600125 or dominant-negative blockade of PERK-mediated eIF2α phosphorylation impaired prodigiosin-induced CHOP up-regulation and PARP cleavage. Collectively, these results identified ER stress-mediated cell death as a mode-of-action of prodigiosin's tumoricidal effect. Mechanistically, prodigiosin engages the IRE1–JNK and PERK–eIF2α branches of the UPR signaling to up-regulate CHOP, which in turn mediates BCL2 suppression to induce cell death. Highlights: ► Prodigiosin is a bacterial tripyrrole pigment with potent anticancer effect. ► Prodigiosin is herein identified

  5. Anti-oxidants do not prevent bile acid-induced cell death in rat hepatocytes.

    NARCIS (Netherlands)

    Woudenberg-Vrenken, T.E.; Buist-Homan, M.; Conde de la Rosa, L.; Faber, K.N.; Moshage, H.

    2010-01-01

    BACKGROUND: Bile acids, reactive oxygen species (ROS) and inflammatory cytokines are crucial regulators of cell death in acute and chronic liver diseases. The contribution of each factor to hepatocyte death, either apoptosis or necrosis, has not been clarified as yet. It has been suggested that the

  6. Anti-oxidants do not prevent bile acid-induced cell death in rat hepatocytes

    NARCIS (Netherlands)

    Woudenberg-Vrenken, Titia E.; Buist-Homan, Manon; Conde de la Rosa, Laura; Faber, Klaas Nico; Moshage, Han

    2010-01-01

    Background Bile acids, reactive oxygen species (ROS) and inflammatory cytokines are crucial regulators of cell death in acute and chronic liver diseases. The contribution of each factor to hepatocyte death, either apoptosis or necrosis, has not been clarified as yet. It has been suggested that the

  7. [Novel Anticancer Strategy Targeting Switch Mechanisms in Two Types of Cell Death: Necrosis and Apoptosis].

    Science.gov (United States)

    Sato, Akira

    2017-01-01

     Two types of cell death, necrosis and apoptosis, are defined in terms of cell death morphological features. We have been studying the mechanisms by which cell death processes are switched during the treatment of mouse tumor FM3A with anticancer, 5-fluoro-2'-deoxyuridine (FUdR): it induces original clone F28-7 to necrosis, but its sub-clone F28-7-A to apoptosis. We identified several such switch regulators of cell death: heat shock protein 90 (HSP90), lamin-B1, cytokeratin-19, and activating transcription factor 3 (ATF3), by using transcriptomic, proteomic analyses and siRNA screening. For example, the inhibition of HSP90 by its inhibitor geldanamycin in F28-7 caused a shift from necrosis to apoptosis. We also observed that the knockdown of lamin-B1, cytokeratin-19, or ATF3 expression in F28-7 resulted in a shift from necrosis to apoptosis. Recently, we used microRNA (miRNA, miR) microarray analyses to investigate the miRNA expression profiles in these sister cells. The miR-351 and miR-743a were expressed at higher levels in F28-7-A than in F28-7. Higher expression of miR-351 or miR-743a in F28-7, induced by transfecting the miR mimics, resulted in a switch of cell death mode: necrosis to apoptosis. Furthermore, transfection of an miR-351 inhibitor into F28-7-A resulted in morphological changes, and mode of cell death from apoptosis to necrosis. These findings suggest that the identified cell death regulators may have key roles in switching cell death mode. Possible mechanisms involving cell death regulators in the switch of necrosis or apoptosis are discussed. We propose a novel anticancer strategy targeting the switch regulators of necrosis or apoptosis.

  8. Cholesterol and Peroxidized Cardiolipin in Mitochondrial Membrane Properties, Permeabilization and Cell Death

    Science.gov (United States)

    Montero, Joan; Mari, Montserrat; Colell, Anna; Morales, Albert; Basañez, Gorka; Garcia-Ruiz, Carmen; Fernández-Checa, Jose C.

    2010-01-01

    Mitochondria are known to actively regulate cell death with the final phenotype of demise being determined by the metabolic and energetic status of the cell. Mitochondrial membrane permeabilization (MMP) is a critical event in cell death, as it regulates the degree of mitochondrial dysfunction and the release of intermembrane proteins that function in the activation and assembly of caspases. In addition to the crucial role of proapoptotic members of the Bcl-2 family, the lipid composition of the mitochondrial membranes is increasingly recognized to modulate MMP and hence cell death. The unphysiological accumulation of cholesterol in mitochondrial membranes regulates their physical properties, faciliating or impairing MMP during Bax and death ligand-induced cell death depending on the level of mitochondrial GSH (mGSH), which in turn regulates the oxidation status of cardiolipin. Cholesterol-mediated mGSH depletion stimulates TNF-induced reactive oxygen species and subsequent cardiolipin peroxidation, which destabilizes the lipid bilayer and potentiates Bax-induced membrane permeabilization. These data suggest that the balance of mitochondrial cholesterol to peroxidized cardiolipin regulates mitochondrial membrane properties and permeabilization, emerging as a rheostat in cell death. PMID:20153716

  9. Identification of a Cell Death Pathway in Candida albicans during the Response to Pheromone ▿ †

    OpenAIRE

    Alby, Kevin; Schaefer, Dana; Sherwood, Racquel Kim; Jones, Stephen K.; Bennett, Richard J.

    2010-01-01

    Mating in hemiascomycete yeasts involves the secretion of pheromones that induce sexual differentiation in cells of the opposite mating type. Studies in Saccharomyces cerevisiae have revealed that a subpopulation of cells experiences cell death during exposure to pheromone. In this work, we tested whether the phenomenon of pheromone-induced death (PID) also occurs in the opportunistic pathogen Candida albicans. Mating in C. albicans is uniquely regulated by white-opaque phenotypic switching; ...

  10. Plant programmed cell death, ethylene and flower senescence

    NARCIS (Netherlands)

    Woltering, E.J.; Jong, de A.; Hoeberichts, F.A.; Iakimova, E.T.; Kapchina, V.

    2005-01-01

    Programmed cell death (PCD) applies to cell death that is part of the normal life of multicellular organisms. PCD is found throughout the animal and plant kingdoms; it is an active process in which a cell suicide pathway is activated resulting in controlled disassembly of the cell. Most cases of PCD

  11. Montelukast Induces Apoptosis-Inducing Factor-Mediated Cell Death of Lung Cancer Cells

    Directory of Open Access Journals (Sweden)

    Ming-Ju Tsai

    2017-06-01

    Full Text Available Developing novel chemo-prevention techniques and advancing treatment are key elements to beating lung cancer, the most common cause of cancer mortality worldwide. Our previous cohort study showed that cysteinyl leukotriene receptor antagonists, mainly montelukast, decreased the lung cancer risk in asthma patients. In the current study, we conducted in vivo and in vitro experiments to demonstrate the inhibiting effect of montelukast on lung cancer and to investigate the underlying mechanisms. Using Lewis lung carcinoma-bearing mice, we showed that feeding montelukast significantly delayed the tumor growth in mice (p < 0.0001. Montelukast inhibited cell proliferation and colony formation and induced the cell death of lung cancer cells. Further investigation showed the down-regulation of B-cell lymphoma 2 (Bcl-2, up-regulation of Bcl-2 homologous antagonist/killer (Bak, and nuclear translocation of apoptosis-inducing factor (AIF in montelukast-treated lung cancer cells. Montelukast also markedly decreased the phosphorylation of several proteins, such as with no lysine 1 (WNK1, protein kinase B (Akt, extracellular signal-regulated kinase 1/2 (Erk1/2, MAPK/Erk kinase (MEK, and proline-rich Akt substrate of 40-kDa (PRAS40, which might contribute to cell death. In conclusion, montelukast induced lung cancer cell death via the nuclear translocation of AIF. This study confirmed the chemo-preventive effect of montelukast shown in our previous cohort study. The utility of montelukast in cancer prevention and treatment thus deserves further studies.

  12. Montelukast Induces Apoptosis-Inducing Factor-Mediated Cell Death of Lung Cancer Cells.

    Science.gov (United States)

    Tsai, Ming-Ju; Chang, Wei-An; Tsai, Pei-Hsun; Wu, Cheng-Ying; Ho, Ya-Wen; Yen, Meng-Chi; Lin, Yi-Shiuan; Kuo, Po-Lin; Hsu, Ya-Ling

    2017-06-24

    Developing novel chemo-prevention techniques and advancing treatment are key elements to beating lung cancer, the most common cause of cancer mortality worldwide. Our previous cohort study showed that cysteinyl leukotriene receptor antagonists, mainly montelukast, decreased the lung cancer risk in asthma patients. In the current study, we conducted in vivo and in vitro experiments to demonstrate the inhibiting effect of montelukast on lung cancer and to investigate the underlying mechanisms. Using Lewis lung carcinoma-bearing mice, we showed that feeding montelukast significantly delayed the tumor growth in mice (p Montelukast inhibited cell proliferation and colony formation and induced the cell death of lung cancer cells. Further investigation showed the down-regulation of B-cell lymphoma 2 (Bcl-2), up-regulation of Bcl-2 homologous antagonist/killer (Bak), and nuclear translocation of apoptosis-inducing factor (AIF) in montelukast-treated lung cancer cells. Montelukast also markedly decreased the phosphorylation of several proteins, such as with no lysine 1 (WNK1), protein kinase B (Akt), extracellular signal-regulated kinase 1/2 (Erk1/2), MAPK/Erk kinase (MEK), and proline-rich Akt substrate of 40-kDa (PRAS40), which might contribute to cell death. In conclusion, montelukast induced lung cancer cell death via the nuclear translocation of AIF. This study confirmed the chemo-preventive effect of montelukast shown in our previous cohort study. The utility of montelukast in cancer prevention and treatment thus deserves further studies.

  13. Programmed cell death-10 enhances proliferation and protects malignant T cells from apoptosis

    DEFF Research Database (Denmark)

    Lauenborg, Britt; Kopp, Katharina; Krejsgaard, Thorbjørn

    2010-01-01

    of cutaneous T-cell lymphoma (Sezary syndrome) patients. PDCD10 is associated with protein phosphatase-2A, a regulator of mitogenesis and apoptosis in malignant T cells. Inhibition of oncogenic signal pathways [Jak3, Notch1, and nuclear factor-¿B (NF-¿B)] partly inhibits the constitutive PDCD10 expression......The programmed cell death-10 (PDCD10; also known as cerebral cavernous malformation-3 or CCM3) gene encodes an evolutionarily conserved protein associated with cell apoptosis. Mutations in PDCD10 result in cerebral cavernous malformations, an important cause of cerebral hemorrhage. PDCD10...... is associated with serine/threonine kinases and phosphatases and modulates the extracellular signal-regulated kinase pathway suggesting a role in the regulation of cellular growth. Here we provide evidence of a constitutive expression of PDCD10 in malignant T cells and cell lines from peripheral blood...

  14. Curcumin induces apoptosis-independent death in oesophageal cancer cells.

    LENUS (Irish Health Repository)

    O'Sullivan-Coyne, G

    2009-10-06

    Background:Oesophageal cancer incidence is increasing and survival rates remain extremely poor. Natural agents with potential for chemoprevention include the phytochemical curcumin (diferuloylmethane). We have examined the effects of curcumin on a panel of oesophageal cancer cell lines.Methods:MTT (3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assays and propidium iodide staining were used to assess viability and DNA content, respectively. Mitotic catastrophe (MC), apoptosis and autophagy were defined by both morphological criteria and markers such as MPM-2, caspase 3 cleavage and monodansylcadaverine (MDC) staining. Cyclin B and poly-ubiquitinated proteins were assessed by western blotting.Results:Curcumin treatment reduces viability of all cell lines within 24 h of treatment in a 5-50 muM range. Cytotoxicity is associated with accumulation in G2\\/M cell-cycle phases and distinct chromatin morphology, consistent with MC. Caspase-3 activation was detected in two out of four cell lines, but was a minor event. The addition of a caspase inhibitor zVAD had a marginal or no effect on cell viability, indicating predominance of a non-apoptotic form of cell death. In two cell lines, features of both MC and autophagy were apparent. Curcumin-responsive cells were found to accumulate poly-ubiquitinated proteins and cyclin B, consistent with a disturbance of the ubiquitin-proteasome system. This effect on a key cell-cycle checkpoint regulator may be responsible for the mitotic disturbances and consequent cytotoxicity of this drug.Conclusion:Curcumin can induce cell death by a mechanism that is not reliant on apoptosis induction, and thus represents a promising anticancer agent for prevention and treatment of oesophageal cancer.British Journal of Cancer advance online publication, 6 October 2009; doi:10.1038\\/sj.bjc.6605308 www.bjcancer.com.

  15. Curcumin induces apoptosis-independent death in oesophageal cancer cells.

    LENUS (Irish Health Repository)

    O'Sullivan-Coyne, G

    2012-01-31

    BACKGROUND: Oesophageal cancer incidence is increasing and survival rates remain extremely poor. Natural agents with potential for chemoprevention include the phytochemical curcumin (diferuloylmethane). We have examined the effects of curcumin on a panel of oesophageal cancer cell lines. METHODS: MTT (3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assays and propidium iodide staining were used to assess viability and DNA content, respectively. Mitotic catastrophe (MC), apoptosis and autophagy were defined by both morphological criteria and markers such as MPM-2, caspase 3 cleavage and monodansylcadaverine (MDC) staining. Cyclin B and poly-ubiquitinated proteins were assessed by western blotting. RESULTS: Curcumin treatment reduces viability of all cell lines within 24 h of treatment in a 5-50 muM range. Cytotoxicity is associated with accumulation in G2\\/M cell-cycle phases and distinct chromatin morphology, consistent with MC. Caspase-3 activation was detected in two out of four cell lines, but was a minor event. The addition of a caspase inhibitor zVAD had a marginal or no effect on cell viability, indicating predominance of a non-apoptotic form of cell death. In two cell lines, features of both MC and autophagy were apparent. Curcumin-responsive cells were found to accumulate poly-ubiquitinated proteins and cyclin B, consistent with a disturbance of the ubiquitin-proteasome system. This effect on a key cell-cycle checkpoint regulator may be responsible for the mitotic disturbances and consequent cytotoxicity of this drug. CONCLUSION: Curcumin can induce cell death by a mechanism that is not reliant on apoptosis induction, and thus represents a promising anticancer agent for prevention and treatment of oesophageal cancer.

  16. Anticancer metal drugs and immunogenic cell death.

    Science.gov (United States)

    Terenzi, Alessio; Pirker, Christine; Keppler, Bernhard K; Berger, Walter

    2016-12-01

    Conventional chemotherapeutics, but also innovative precision anticancer compounds, are commonly perceived to target primarily the cancer cell compartment. However, recently it was discovered that some of these compounds can also exert immunomodulatory activities which might be exploited to synergistically enhance their anticancer effects. One specific phenomenon of the interplay between chemotherapy and the anticancer immune response is the so-called "immunogenic cell death" (ICD). ICD was discovered based on a vaccination effect exerted by cancer cells dying from pretreatment with certain chemotherapeutics, termed ICD inducers, in syngeneic transplantation mouse models. Interestingly, only a minority of drugs is able to trigger ICD without a clear-cut relation to chemical structures or their primary modes-of-action. Nevertheless, generation of reactive oxygen species (ROS) and induction of endoplasmic reticulum (ER) stress are clearly linked to ICD. With regard to metal drugs, oxaliplatin but not cisplatin is considered a bona fide ICD inducer. Taken into account that several experimental metal compounds are efficient ROS and ER stress mediators, presence of potent ICD inducers within the plethora of novel metal complexes seems feasible and has occasionally been reported. In the light of recent successes in cancer immunotherapy, here we review existing literature regarding anticancer metal drugs and ICD induction. We recommend a more profound investigation of the immunogenic features of experimental anticancer metal drugs. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Morphodynamics of a growing microbial colony driven by cell death

    Science.gov (United States)

    Ghosh, Pushpita; Levine, Herbert

    2017-11-01

    Bacterial cells can often self-organize into multicellular structures with complex spatiotemporal morphology. In this work, we study the spatiotemporal dynamics of a growing microbial colony in the presence of cell death. We present an individual-based model of nonmotile bacterial cells which grow and proliferate by consuming diffusing nutrients on a semisolid two-dimensional surface. The colony spreads by growth forces and sliding motility of cells and undergoes cell death followed by subsequent disintegration of the dead cells in the medium. We model cell death by considering two possible situations: In one of the cases, cell death occurs in response to the limitation of local nutrients, while the other case corresponds to an active death process, known as apoptotic or programmed cell death. We demonstrate how the colony morphology is influenced by the presence of cell death. Our results show that cell death facilitates transitions from roughly circular to highly branched structures at the periphery of an expanding colony. Interestingly, our results also reveal that for the colonies which are growing in higher initial nutrient concentrations, cell death occurs much earlier compared to the colonies which are growing in lower initial nutrient concentrations. This work provides new insights into the branched patterning of growing bacterial colonies as a consequence of complex interplay among the biochemical and mechanical effects.

  18. Doxorubicin-induced cell death requires cathepsin B in HeLa cells.

    Science.gov (United States)

    Bien, S; Rimmbach, C; Neumann, H; Niessen, J; Reimer, E; Ritter, C A; Rosskopf, D; Cinatl, J; Michaelis, M; Schroeder, H W S; Kroemer, H K

    2010-11-15

    The cysteine protease cathepsin B acts as a key player in apoptosis. Cathepsin B-mediated cell death is induced by various stimuli such as ischemia, bile acids or TNFα. Whether cathepsin B can be influenced by anticancer drugs, however, has not been studied in detail. Here, we describe the modulation of doxorubicin-induced cell death by silencing of cathepsin B expression. Previously, it was shown that doxorubicin, in contrast to other drugs, selectively regulates expression and activity of cathepsin B. Selective silencing of cathepsin B by siRNA or the cathepsin B specific inhibitor CA074Me modified doxorubicin-mediated cell death in Hela tumor cells. Both Caspase 3 activation and PARP cleavage were significantly reduced in cells lacking cathepsin B. Moreover, mitochondrial membrane permeabilization as well as the release of cytochrome C and AIF from mitochondria into cytosol induced by doxorubicin were significantly diminished in cathepsin B suppressed cells. In addition, doxorubicin associated down-regulation of XIAP was not observed in cathepsin B silenced cells. Lack of cathepsin B significantly modified cell cycle regulatory proteins such as cdk1, Wee1 and p21 without significant changes in G(1), S or G(2)M cell cycle phases maybe indicating further cell cycle independent actions of these proteins. Consequently, cell viability following doxorubicin was significantly elevated in cells with cathepsin B silencing. In summary, our data strongly suggest a role of cathepsin B in doxorubicin-induced cell death. Therefore, increased expression of cathepsin B in various types of cancer can modify susceptibility towards doxorubicin. Copyright © 2010 Elsevier Inc. All rights reserved.

  19. Escaping Death: Mitochondrial Redox Homeostasis in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Francesco Ciccarese

    2017-06-01

    Full Text Available Reactive oxygen species (ROS are important signaling molecules that act through the oxidation of nucleic acids, proteins, and lipids. Several hallmarks of cancer, including uncontrolled proliferation, angiogenesis, and genomic instability, are promoted by the increased ROS levels commonly found in tumor cells. To counteract excessive ROS accumulation, oxidative stress, and death, cancer cells tightly regulate ROS levels by enhancing scavenging enzymes, which are dependent on the reducing cofactor nicotinamide adenine dinucleotide phosphate (NADPH. This review focuses on mitochondrial ROS homeostasis with a description of six pathways of NADPH production in mitochondria and a discussion of the possible strategies of pharmacological intervention to selectively eliminate cancer cells by increasing their ROS levels.

  20. BH3 Mimetics Reactivate Autophagic Cell Death in Anoxia-Resistant Malignant Glioma Cells

    Directory of Open Access Journals (Sweden)

    Holger Hetschko

    2008-08-01

    Full Text Available Here, we investigated the specific roles of Bcl-2 family members in anoxia tolerance of malignant glioma. Flow cytometry analysis of cell death in 17 glioma cell lines revealed drastic differences in their sensitivity to oxygen withdrawal (<0.1% O2. Cell death correlated with mitochondrial depolarization, cytochrome C release, and translocation of green fluorescent protein (GFP-tagged light chain 3 to autophagosomes but occurred in the absence of caspase activation or phosphatidylserine exposure. In both sensitive and tolerant glioma cell lines, anoxia caused a significant up-regulation of BH3-only genes previously implicated in mediating anoxic cell death in other cell types (BNIP3, NIX, PUMA, and Noxa. In contrast, we detected a strong correlation between anoxia resistance and high expression levels of antiapoptotic Bcl-2 family proteins Bcl-xL, Bcl-2, and Mcl-1 that function to neutralize the proapoptotic activity of BH3-only proteins. Importantly, inhibition of both Bcl-2 and Bcl-xL with the small-molecule BH3 mimetics HA14-1 and BH3I-2′ and by RNA interference reactivated anoxia-induced autophagic cell death in previously resistant glioma cells. Our data suggest that endogenous BH3-only protein induction may not be able to compensate for the high expression of antiapoptotic Bcl-2 family proteins in anoxia-resistant astrocytomas. They also support the conjecture that BH3 mimetics may represent an exciting new approach for the treatment of malignant glioma.

  1. Calpain-3 impairs cell proliferation and stimulates oxidative stress-mediated cell death in melanoma cells.

    Directory of Open Access Journals (Sweden)

    Daniele Moretti

    Full Text Available Calpain-3 is an intracellular cysteine protease, belonging to Calpain superfamily and predominantly expressed in skeletal muscle. In human melanoma cell lines and biopsies, we previously identified two novel splicing variants (hMp78 and hMp84 of Calpain-3 gene (CAPN3, which have a significant lower expression in vertical growth phase melanomas and, even lower, in metastases, compared to benign nevi. In the present study, in order to investigate the pathophysiological role played by the longer Calpain-3 variant, hMp84, in melanoma cells, we over-expressed it in A375 and HT-144 cells. In A375 cells, the enforced expression of hMp84 induces p53 stabilization, and modulates the expression of a few p53- and oxidative stress-related genes. Consistently, hMp84 increases the intracellular production of ROS (Reactive Oxygen Species, which lead to oxidative modification of phospholipids (formation of F2-isoprostanes and DNA damage. Such events culminate in an adverse cell fate, as indicated by the decrease of cell proliferation and by cell death. To a different extent, either the antioxidant N-acetyl-cysteine or the p53 inhibitor, Pifithrin-α, recover cell viability and decrease ROS formation. Similarly to A375 cells, hMp84 over-expression causes inhibition of cell proliferation, cell death, and increase of both ROS levels and F2-isoprostanes also in HT-144 cells. However, in these cells no p53 accumulation occurs. In both cell lines, no significant change of cell proliferation and cell damage is observed in cells over-expressing the mutant hMp84C42S devoid of its enzymatic activity, suggesting that the catalytic activity of hMp84 is required for its detrimental effects. Since a more aggressive phenotype is expected to benefit from down-regulation of mechanisms impairing cell growth and survival, we envisage that Calpain-3 down-regulation can be regarded as a novel mechanism contributing to melanoma progression.

  2. Stroke and cardiac cell death: Two peas in a pod.

    Science.gov (United States)

    Gonzales-Portillo, Chiara; Ishikawa, Hiroto; Shinozuka, Kazutaka; Tajiri, Naoki; Kaneko, Yuji; Borlongan, Cesar V

    2016-03-01

    A close pathological link between stroke brain and heart failure may exist. Here, we discuss relevant laboratory and clinical reports demonstrating neural and cardiac myocyte cell death following ischemic stroke. Although various overlapping risk factors exist between cerebrovascular incidents and cardiac incidents, stroke therapy has largely neglected the cardiac pathological consequences. Recent preclinical stroke studies have implicated an indirect cell death pathway, involving toxic molecules, that originates from the stroke brain and produces cardiac cell death. In concert, previous laboratory reports have revealed a reverse cell death cascade, in that cardiac arrest leads to ischemic cell death in the brain. A deeper understanding of the crosstalk of cell death pathways between stroke and cardiac failure will facilitate the development of novel treatments designed to arrest the global pathology of both diseases thereby improving the clinical outcomes of patients diagnosed with stroke and heart failure. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. The molecular ecophysiology of programmed cell death in marine phytoplankton.

    Science.gov (United States)

    Bidle, Kay D

    2015-01-01

    Planktonic, prokaryotic, and eukaryotic photoautotrophs (phytoplankton) share a diverse and ancient evolutionary history, during which time they have played key roles in regulating marine food webs, biogeochemical cycles, and Earth's climate. Because phytoplankton represent the basis of marine ecosystems, the manner in which they die critically determines the flow and fate of photosynthetically fixed organic matter (and associated elements), ultimately constraining upper-ocean biogeochemistry. Programmed cell death (PCD) and associated pathway genes, which are triggered by a variety of nutrient stressors and are employed by parasitic viruses, play an integral role in determining the cell fate of diverse photoautotrophs in the modern ocean. Indeed, these multifaceted death pathways continue to shape the success and evolutionary trajectory of diverse phytoplankton lineages at sea. Research over the past two decades has employed physiological, biochemical, and genetic techniques to provide a novel, comprehensive, mechanistic understanding of the factors controlling this key process. Here, I discuss the current understanding of the genetics, activation, and regulation of PCD pathways in marine model systems; how PCD evolved in unicellular photoautotrophs; how it mechanistically interfaces with viral infection pathways; how stress signals are sensed and transduced into cellular responses; and how novel molecular and biochemical tools are revealing the impact of PCD genes on the fate of natural phytoplankton assemblages.

  4. The Molecular Ecophysiology of Programmed Cell Death in Marine Phytoplankton

    Science.gov (United States)

    Bidle, Kay D.

    2015-01-01

    Planktonic, prokaryotic, and eukaryotic photoautotrophs (phytoplankton) share a diverse and ancient evolutionary history, during which time they have played key roles in regulating marine food webs, biogeochemical cycles, and Earth's climate. Because phytoplankton represent the basis of marine ecosystems, the manner in which they die critically determines the flow and fate of photosynthetically fixed organic matter (and associated elements), ultimately constraining upper-ocean biogeochemistry. Programmed cell death (PCD) and associated pathway genes, which are triggered by a variety of nutrient stressors and are employed by parasitic viruses, play an integral role in determining the cell fate of diverse photoautotrophs in the modern ocean. Indeed, these multifaceted death pathways continue to shape the success and evolutionary trajectory of diverse phytoplankton lineages at sea. Research over the past two decades has employed physiological, biochemical, and genetic techniques to provide a novel, comprehensive, mechanistic understanding of the factors controlling this key process. Here, I discuss the current understanding of the genetics, activation, and regulation of PCD pathways in marine model systems; how PCD evolved in unicellular photoautotrophs; how it mechanistically interfaces with viral infection pathways; how stress signals are sensed and transduced into cellular responses; and how novel molecular and biochemical tools are revealing the impact of PCD genes on the fate of natural phytoplankton assemblages.

  5. Senescence and programmed cell death : substance or semantics?

    NARCIS (Netherlands)

    Doorn, van W.G.; Woltering, E.J.

    2004-01-01

    The terms senescence and programmed cell death (PCD) have led to some confusion. Senescence as visibly observed in, for example, leaf yellowing and petal wilting, has often been taken to be synonymous with the programmed death of the constituent cells. PCD also obviously refers to cells, which show

  6. The roles of mitochondria in radiation-induced autophagic cell death in cervical cancer cells.

    Science.gov (United States)

    Chen, Zongyan; Wang, Benli; Yu, Feifei; Chen, Qiao; Tian, Yuxi; Ma, Shumei; Liu, Xiaodong

    2016-03-01

    Mitochondria as the critical powerhouse of eukaryotic cells play important roles in regulating cell survival or cell death. Under numerous stimuli, impaired mitochondria will generate massive reactive oxygen species (ROS) which participate in the regulation of vital signals and could even determine the fate of cancer cells. While the roles of mitochondria in radiation-induced autophagic cell death still need to be elucidated. Human cervical cancer cell line, Hela, was used, and the SOD2 silencing model (SOD2-Ri) was established by gene engineering. Cell viability was detected by methyl thiazolyl tetrazolium (MTT) assays, MitoTracker Green staining was used to detect mitochondrial mass, Western blot was used to detect protein expression, and the level of ROS, autophagy, and mitochondrial membrane potential (MMP) were analyzed by flow cytometry. Ionizing radiation (IR) could induce the increase of MAPLC3-II/MAPLC3-I ratio, Beclin1 expression, and ROS generation but decrease the MMP in a time-dependent manner. After SOD2 silencing, the IR-induced changes of ROS and the MMP were significantly enhanced. Moreover, both the radio sensitivity and autophagy increased in SOD2-Ri cells. Whereas, compared with SOD2-Ri, the opposite results were obtained by NAC, an antioxidant. After the treatment with the inhibitor of mitochondrial electron-transport chain complex II, thenoyltrifluoroacetone (TTFA), the rate of autophagy, ROS, and the total cell death induced by IR increased. In addition, the decrease of MMP was more obvious. However, these results were reversed by cyclosporine A (CsA). IR could induce ROS generation and mitochondrial damage which lead to autophagic cell death in Hela cells.

  7. Programmed Cell Death During Female Gametophyte Development

    Energy Technology Data Exchange (ETDEWEB)

    Drews, Gary, N.

    2004-09-15

    Endosperm is a storage tissue in the angiosperm seed that is important both biologically and agriculturally. Endosperm is biologically important because it provides nutrients to the embryo during seed development and agriculturally important because it is a significant source of food, feed, and industrial raw materials. Approximately two-thirds of human calories are derived from endosperm, either directly or indirectly through animal feed. Furthermore, endosperm is used as a raw material for numerous industrial products including ethanol. A major event in endosperm development is the transition between the syncytial phase, during which the endosperm nuclei undergo many rounds of mitosis without cytokinesis, and the cellularized phase, during which cell walls form around the endosperm nuclei. Understanding how the syncytial-cellular transition is regulated is agriculturally important because it influences seed size, seed sink strength, and grain weight. However, the molecular processes controlling this transition are not understood. This project led to the identification of the AGL62 gene that regulates the syncytial-cellular transition during endosperm development. AGL62 is expressed during the syncytial phase and suppresses endosperm cellularization during this period. AGL62 most likely does so by suppressing the expression of genes required for cellularization. At the end of the syncytial phase, the FIS PcG complex suppresses AGL62 expression, which allows expression of the cellularization genes and triggers the initiation of the cellularized phase. Endosperm arises following fertilization of the central cell within the female gametophyte. This project also led to the identification of the AGL80 gene that is required for development of the central cell into the endosperm. Within the ovule and seed, AGL80 is expressed exclusively in the central cell and uncellularized endosperm. AGL80 is required for expression of several central cell-expressed genes, including

  8. Programmed cell death and cell extrusion in rat duodenum

    DEFF Research Database (Denmark)

    Schauser, Kirsten; Larsson, Lars-Inge

    2005-01-01

    The small intestinal epithelium is continously renewed through a balance between cell division and cell loss. How this balance is achieved is uncertain. Thus, it is unknown to what extent programmed cell death (PCD) contributes to intestinal epithelial cell loss. We have used a battery...... of techniques detecting the events associated with PCD in order to better understand its role in the turnover of the intestinal epithelium, including modified double- and triple-staining techniques for simultaneously detecting multiple markers of PCD in individual cells. Only a partial correlation between TUNEL...... positivity for DNA fragmentation, c-jun phosphorylation on serine-63, positivity for activated caspase-3 and apoptotic morphology was observed. Our results show that DNA fragmentation does not invariable correlate to activation of caspase-3. Moreover, many cells were found to activate caspase-3 early...

  9. Cell Death and Ageing – A Question of Cell Type

    Directory of Open Access Journals (Sweden)

    Pidder Jansen-Dürr

    2002-01-01

    Full Text Available Replicative senescence of human cells in primary culture is a widely accepted model for studying the molecular mechanisms of human ageing. The standard model used for studying human ageing consists of fibroblasts explanted from the skin and grown into in vitro senescence. From this model, we have learned much about molecular mechanisms underlying the human ageing process; however, the model presents clear limitations. In particular, a long-standing dogma holds that replicative senescence involves resistance to apoptosis, a belief that has led to considerable confusion concerning the role of apoptosis during human ageing. While there are data suggesting that apoptotic cell death plays a key role for ageing in vitro and in the pathogenesis of various age-associated diseases, this is not reflected in the current literature on in vitro senescence. In this article, I summarize key findings concerning the relationship between apoptosis and ageing in vivo and also review the literature concerning the role of apoptosis during in vitro senescence. Recent experimental findings, summarized in this article, suggest that apoptotic cell death (and probably other forms of cell death are important features of the ageing process that can also be recapitulated in tissue culture systems to some extent. Another important lesson to learn from these studies is that mechanisms of in vivo senescence differ considerably between various histotypes.

  10. p73 engages A2B receptor signalling to prime cancer cells to chemotherapy-induced death

    NARCIS (Netherlands)

    Long, J. S.; Schoonen, P. M.; Graczyk, D.; O'Prey, J.; Ryan, K. M.

    2015-01-01

    Tumour cells often acquire the ability to escape cell death, a key event leading to the development of cancer. In almost half of all human cancers, the capability to induce cell death is reduced by the mutation and inactivation of p53, a tumour suppressor protein that is a central regulator of

  11. The nuclear receptor NR4A1 induces a form of cell death dependent on autophagy in mammalian cells.

    Directory of Open Access Journals (Sweden)

    Jimena Bouzas-Rodríguez

    Full Text Available The control of cell death is a biological process essential for proper development, and for preventing devastating pathologies like cancer and neurodegeneration. On the other hand, autophagy regulation is essential for protein and organelle degradation, and its dysfunction is associated with overlapping pathologies like cancer and neurodegeneration, but also for microbial infection and aging. In the present report we show that two evolutionarily unrelated receptors--Neurokinin 1 Receptor (NK(1R, a G-protein coupled receptor, and Insulin-like Growth Factor 1 Receptor (IGF1R, a tyrosine kinase receptor--both induce non-apoptotic cell death with autophagic features and requiring the activity of the autophagic core machinery proteins PI3K-III, Beclin-1 and Atg7. Remarkably, this form of cell death occurs in apoptosis-competent cells. The signal transduction pathways engaged by these receptors both converged on the activation of the nuclear receptor NR4A1, which has previously been shown to play a critical role in some paradigms of apoptosis and in NK(1R-induced cell death. The activity of NR4A1 was necessary for IGF1R-induced cell death, as well as for a canonical model of cell death by autophagy induced by the presence of a pan-caspase inhibitor, suggesting that NR4A1 is a general modulator of this kind of cell death. During cell death by autophagy, NR4A1 was transcriptionally competent, even though a fraction of it was present in the cytoplasm. Interestingly, NR4A1 interacts with the tumor suppressor p53 but not with Beclin-1 complex. Therefore the mechanism to promote cell death by autophagy might involve regulation of gene expression, as well as protein interactions. Understanding the molecular basis of autophagy and cell death mediation by NR4A1, should provide novel insights and targets for therapeutic intervention.

  12. Calcium and cell death signaling in neurodegeneration and aging

    Directory of Open Access Journals (Sweden)

    Soraya Smaili

    2009-09-01

    Full Text Available Transient increase in cytosolic (Cac2+ and mitochondrial Ca2+ (Ca m2+ are essential elements in the control of many physiological processes. However, sustained increases in Ca c2+ and Ca m2+ may contribute to oxidative stress and cell death. Several events are related to the increase in Ca m2+, including regulation and activation of a number of Ca2+ dependent enzymes, such as phospholipases, proteases and nucleases. Mitochondria and endoplasmic reticulum (ER play pivotal roles in the maintenance of intracellular Ca2+ homeostasis and regulation of cell death. Several lines of evidence have shown that, in the presence of some apoptotic stimuli, the activation of mitochondrial processes maylead to the release of cytochrome c followed by the activation of caspases, nuclear fragmentation and apoptotic cell death. The aim of this review was to show how changes in calcium signaling can be related to the apoptotic cell death induction. Calcium homeostasis was also shown to be an important mechanism involved in neurodegenerative and aging processes.Aumentos transientes no cálcio citosólico (Ca c2+ e mitocondrial (Ca m2+ são elementos essenciais no controle de muitos processos fisiológicos. No entanto, aumentos sustentados do Ca c2+ e do Ca m2+ podem contribuir para o estresse oxidativo ea morte celular. Muitos eventos estão relacionados ao aumentono Ca c2+, incluindo a regulação e ativação de várias enzimas dependentes de Ca2+ como as fosfolipases, proteases e nucleases. A mitocôndria e o retículo endoplasmático têm um papel central na manutenção da homeostase intracellular de Ca c2+ e na regulação da morte celular. Várias evidências mostraram que, na presença de certos estímulos apoptóticos, a ativação dos processos mitocondriais pode promover a liberação de citocromo c, seguida da ativação de caspases, fragmentação nuclear e morte celular por apoptose. O objetivo desta revisão é mostrar como aumentos na sinalização de

  13. Patterns of cell death in the perinatal mouse forebrain.

    Science.gov (United States)

    Mosley, Morgan; Shah, Charisma; Morse, Kiriana A; Miloro, Stephen A; Holmes, Melissa M; Ahern, Todd H; Forger, Nancy G

    2017-01-01

    The importance of cell death in brain development has long been appreciated, but many basic questions remain, such as what initiates or terminates the cell death period. One obstacle has been the lack of quantitative data defining exactly when cell death occurs. We recently created a "cell death atlas," using the detection of activated caspase-3 (AC3) to quantify apoptosis in the postnatal mouse ventral forebrain and hypothalamus, and found that the highest rates of cell death were seen at the earliest postnatal ages in most regions. Here we have extended these analyses to prenatal ages and additional brain regions. We quantified cell death in 16 forebrain regions across nine perinatal ages from embryonic day (E) 17 to postnatal day (P) 11 and found that cell death peaks just after birth in most regions. We found greater cell death in several regions in offspring delivered vaginally on the day of parturition compared with those of the same postconception age but still in utero at the time of collection. We also found massive cell death in the oriens layer of the hippocampus on P1 and in regions surrounding the anterior crossing of the corpus callosum on E18 as well as the persistence of large numbers of cells in those regions in adult mice lacking the pro-death Bax gene. Together these findings suggest that birth may be an important trigger of neuronal cell death and identify transient cell groups that may undergo wholesale elimination perinatally. J. Comp. Neurol. 525:47-64, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  14. A Proteolytic Cascade Controls Lysosome Rupture and Necrotic Cell Death Mediated by Lysosome-Destabilizing Adjuvants

    OpenAIRE

    Jürgen Brojatsch; Heriberto Lima; Alak K Kar; Jacobson, Lee S.; Muehlbauer, Stefan M.; Kartik Chandran; Felipe Diaz-Griffero

    2014-01-01

    Recent studies have linked necrotic cell death and proteolysis of inflammatory proteins to the adaptive immune response mediated by the lysosome-destabilizing adjuvants, alum and Leu-Leu-OMe (LLOMe). However, the mechanism by which lysosome-destabilizing agents trigger necrosis and proteolysis of inflammatory proteins is poorly understood. The proteasome is a cellular complex that has been shown to regulate both necrotic cell death and proteolysis of inflammatory proteins. We found that the p...

  15. Mechanisms of Ethanol-induced Death of Cerebellar Granule Cells

    Science.gov (United States)

    Luo, Jia

    2012-01-01

    Maternal ethanol exposure during pregnancy may cause fetal alcohol spectrum disorders (FASD). FASD is the leading cause of mental retardation. The most deleterious effect of fetal alcohol exposure is inducing neuroapoptosis in the developing brain. Ethanol-induced loss of neurons in the central nervous system (CNS) underlies many of the behavioral deficits observed in FASD. The cerebellum is one of the brain areas that is most susceptible to ethanol during development. Ethanol exposure causes a loss of both cerebellar Purkinje cells and granule cells. This review focuses on the toxic effect of ethanol on cerebellar granule cells (CGC) and the underlying mechanisms. Both in vitro and in vivo studies indicate that ethanol induces apoptotic death of CGC. The vulnerability of CGC to ethanol-induced death diminishes over time as neurons mature. Several mechanisms for ethanol-induced apoptosis of CGC have been suggested. These include inhibition of NMDA receptors, interference with signaling by neurotrophic factors, induction of oxidative stress, modulation of retinoid acid signaling, disturbance of potassium channel currents, thiamine deficiency, and disruption of translational regulation. Cultures of CGC provide an excellent system to investigate cellular/molecular mechanisms of ethanol-induced neurodegeneration and to evaluate interventional strategies. This review will also discuss the approaches leading to neuroprotection against ethanol-induced neuroapoptosis. PMID:20927663

  16. "(Not) all (dead) things share the same breath": identification of cell death mechanisms in anticancer therapy.

    Science.gov (United States)

    Rello-Varona, Santiago; Herrero-Martín, David; López-Alemany, Roser; Muñoz-Pinedo, Cristina; Tirado, Oscar M

    2015-03-15

    During the last decades, the knowledge of cell death mechanisms involved in anticancer therapy has grown exponentially. However, in many studies, cell death is still described in an incomplete manner. The frequent use of indirect proliferation assays, unspecific probes, or bulk analyses leads too often to misunderstandings regarding cell death events. There is a trend to focus on molecular or genetic regulations of cell demise without a proper characterization of the phenotype that is the object of this study. Sometimes, cancer researchers can feel overwhelmed or confused when faced with such a corpus of detailed insights, nomenclature rules, and debates about the accuracy of a particular probe or assay. On the basis of the information available, we propose a simple guide to distinguish forms of cell death in experimental settings using cancer cell lines. ©2015 American Association for Cancer Research.

  17. Mediation of autophagic cell death by type 3 ryanodine receptor (RyR3 in adult hippocampal neural stem cells

    Directory of Open Access Journals (Sweden)

    Kyung Min eChung

    2016-05-01

    Full Text Available Cytoplasmic Ca2+ actively engages in diverse intracellular processes from protein synthesis, folding and trafficking to cell survival and death. Dysregulation of intracellular Ca2+ levels is observed in various neuropathological states including Alzheimer’s and Parkinson’s diseases. Ryanodine receptors (RyRs and IP3 receptors (IP3Rs, the main Ca2+ release channels located in endoplasmic reticulum (ER membranes, are known to direct various cellular events such as autophagy and apoptosis. Here we investigated the intracellular Ca2+-mediated regulation of survival and death of adult hippocampal neural stem (HCN cells utilizing an insulin withdrawal model of autophagic cell death. Despite comparable expression levels of RyR and IP3R transcripts in HCN cells at normal state, the expression levels of RyRs — especially RyR3 — were markedly upregulated upon insulin withdrawal. While treatment with the RyR agonist caffeine significantly promoted the autophagic death of insulin-deficient HCN cells, treatment with its inhibitor dantrolene prevented the induction of autophagy following insulin withdrawal. Furthermore, CRISPR/Cas9-mediated knockout of the RyR3 gene abolished autophagic cell death of HCN cells. This study delineates a distinct, RyR3-mediated ER Ca2+ regulation of autophagy and programmed cell death in neural stem cells. Our findings provide novel insights into the critical, yet understudied mechanisms underlying the regulatory function of ER Ca2+ in neural stem cell biology.

  18. Abortive autophagy induces endoplasmic reticulum stress and cell death in cancer cells.

    Directory of Open Access Journals (Sweden)

    Sofie Claerhout

    Full Text Available Autophagic cell death or abortive autophagy has been proposed to eliminate damaged as well as cancer cells, but there remains a critical gap in our knowledge in how this process is regulated. The goal of this study was to identify modulators of the autophagic cell death pathway and elucidate their effects on cellular signaling and function. The result of our siRNA library screenings show that an intact coatomer complex I (COPI is obligatory for productive autophagy. Depletion of COPI complex members decreased cell survival and impaired productive autophagy which preceded endoplasmic reticulum stress. Further, abortive autophagy provoked by COPI depletion significantly altered growth factor signaling in multiple cancer cell lines. Finally, we show that COPI complex members are overexpressed in an array of cancer cell lines and several types of cancer tissues as compared to normal cell lines or tissues. In cancer tissues, overexpression of COPI members is associated with poor prognosis. Our results demonstrate that the coatomer complex is essential for productive autophagy and cellular survival, and thus inhibition of COPI members may promote cell death of cancer cells when apoptosis is compromised.

  19. Xylanse-Induced cell death events in detached tobacco leaves

    NARCIS (Netherlands)

    Yordanova, Z.P.; Kapchina-Toteva, V.M.; Woltering, E.J.; Batchvarova, R.B.; Yakimova, E.T.

    2009-01-01

    Plant-pathogen interactions are associated with plant defense mechanism known as hypersensitive response (HR), which is a form of programmed cell death (PCD). In the present work we have tested the potency of chemicals, proven as PCD inhibitors in other systems, to prevent the spread of cell death

  20. Hydrogen peroxide as a signal controlling plant programmed cell death

    NARCIS (Netherlands)

    Gechev, Tsanko S.; Hille, Jacques

    2005-01-01

    Hydrogen peroxide (H2O2) has established itself as a key player in stress and programmed cell death responses, but little is known about the signaling pathways leading from H2O2 to programmed cell death in plants. Recently, identification of key regulatory mutants and near-full genome coverage

  1. Chemical -induced apoptotic cell death in tomato cells : involvement of caspase-like proteases

    NARCIS (Netherlands)

    Jong, de A.J.; Hoeberichts, F.A.; Yakimova, E.T.; Maximova, E.; Woltering, E.J.

    2000-01-01

    A new system to study programmed cell death in plants is described. Tomato (Lycopersicon esculentum Mill.) suspension cells were induced to undergo programmed cell death by treatment with known inducers of apoptosis in mammalian cells. This chemical-induced cell death was accompanied by the

  2. MicroRNAs: key players in the immune system, differentiation, tumorigenesis and cell death

    National Research Council Canada - National Science Library

    Schickel, R; Boyerinas, B; Park, S-M; Peter, M E

    2008-01-01

    ... fundamental processes such as differentiation, cell growth and cell death, the study of the role of miRNAs in human neoplasms holds great promise for novel forms of therapy. Here, we summarize the role of miRNAs and their targets in contributing to human cancers and their function as regulators of apoptotic pathways and the immune system. Onco...

  3. Targeting Thioredoxin-1 by dimethyl fumarate induces ripoptosome-mediated cell death.

    Science.gov (United States)

    Schroeder, Anne; Warnken, Uwe; Röth, Daniel; Klika, Karel D; Vobis, Diana; Barnert, Andrea; Bujupi, Fatmire; Oberacker, Tina; Schnölzer, Martina; Nicolay, Jan P; Krammer, Peter H; Gülow, Karsten

    2017-02-24

    Constitutively active NFκB promotes survival of many cancers, especially T-cell lymphomas and leukemias by upregulating antiapoptotic proteins such as inhibitors of apoptosis (IAPs) and FLICE-like inhibitory proteins (cFLIPs). IAPs and cFLIPs negatively regulate the ripoptosome, which mediates cell death in an apoptotic or necroptotic manner. Here, we demonstrate for the first time, that DMF antagonizes NFκB by suppressing Thioredoxin-1 (Trx1), a major regulator of NFκB transcriptional activity. DMF-mediated inhibition of NFκB causes ripoptosome formation via downregulation of IAPs and cFLIPs. In addition, DMF promotes mitochondrial Smac release and subsequent degradation of IAPs, further enhancing cell death in tumor cells displaying constitutive NFκB activity. Significantly, CTCL patients treated with DMF display substantial ripoptosome formation and caspase-3 cleavage in T-cells. DMF induces cell death predominantly in malignant or activated T-cells. Further, we show that malignant T-cells can die by both apoptosis and necroptosis, in contrast to resting T-cells, which are restricted to apoptosis upon DMF administration. In summary, our data provide new mechanistic insight in the regulation of cell death by targeting NFκB via Trx1 in cancer. Thus, interference with Trx1 activity is a novel approach for treatment of NFκB-dependent tumors.

  4. Independent controls for neocortical neuron production and histogenetic cell death

    Science.gov (United States)

    Verney, C.; Takahashi, T.; Bhide, P. G.; Nowakowski, R. S.; Caviness, V. S. Jr

    2000-01-01

    We estimated the proportion of cells eliminated by histogenetic cell death during the first 2 postnatal weeks in areas 1, 3 and 40 of the mouse parietal neocortex. For each layer and for the subcortical white matter in each neocortical area, the number of dying cells per mm(2) was calculated and the proportionate cell death for each day of the 2-week interval was estimated. The data show that cell death proceeds essentially uniformly across the neocortical areas and layers and that it does not follow either the spatiotemporal gradient of cell cycle progression in the pseudostratified ventricular epithelium of the cerebral wall, the source of neocortical neurons, or the 'inside-out' neocortical neuronogenetic sequence. Therefore, we infer that the control mechanisms of neocortical histogenetic cell death are independent of mechanisms controlling neuronogenesis or neuronal migration but may be associated with the ingrowth, expansion and a system-wide matching of neuronal connectivity. Copyright 2000 S. Karger AG, Basel.

  5. Cross-talk of nitric oxide and reactive oxygen species in plant programed cell death

    OpenAIRE

    Yiqin eWang; Loake, Gary J.; Chengcai eChu

    2013-01-01

    In plants, programed cell death (PCD) is an important mechanism to regulate multiple aspects of growth and development, as well as to remove damaged or infected cells during responses to environmental stresses and pathogen attacks. Under biotic and abiotic stresses, plant cells exhibit a rapid synthesis of nitric oxide (NO) and a parallel accumulation of reactive oxygen species (ROS). Frequently, these responses trigger a PCD process leading to an intrinsic execution of plant cells. The accum...

  6. Noncanonical cell death in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Kinet, Maxime J; Shaham, Shai

    2014-01-01

    The nematode Caenorhabditis elegans has served as a fruitful setting for cell death research for over three decades. A conserved pathway of four genes, egl-1/BH3-only, ced-9/Bcl-2, ced-4/Apaf-1, and ced-3/caspase, coordinates most developmental cell deaths in C. elegans. However, other cell death forms, programmed and pathological, have also been described in this animal. Some of these share morphological and/or molecular similarities with the canonical apoptotic pathway, while others do not. Indeed, recent studies suggest the existence of an entirely novel mode of programmed developmental cell destruction that may also be conserved beyond nematodes. Here, we review evidence for these noncanonical pathways. We propose that different cell death modalities can function as backup mechanisms for apoptosis, or as tailor-made programs that allow specific dying cells to be efficiently cleared from the animal. © 2014 Elsevier Inc. All rights reserved.

  7. Metacaspase-8 Modulates Programmed Cell Death Induced by Ultraviolet Light and H2O2 in Arabidopsis

    NARCIS (Netherlands)

    He, R.; Drury, G.E.; Rotari, V.I.; Gordon, A.; Willer, M.; Farzaneh, T.; Woltering, E.J.; Gallois, P.

    2008-01-01

    Programmed cell death (PCD) is a genetically controlled cell death that is regulated during development and activated in response to environmental stresses or pathogen infection. The degree of conservation of PCD across kingdoms and phylum is not yet clear; however, whereas caspases are proteases

  8. Gene expression analysis of cell death induction by Taurolidine in different malignant cell lines

    Science.gov (United States)

    2010-01-01

    Background The anti-infective agent Taurolidine (TRD) has been shown to have cell death inducing properties, but the mechanism of its action is largely unknown. The aim of this study was to identify potential common target genes modulated at the transcriptional level following TRD treatment in tumour cell lines originating from different cancer types. Methods Five different malignant cell lines (HT29, Chang Liver, HT1080, AsPC-1 and BxPC-3) were incubated with TRD (100 μM, 250 μM and 1000 μM). Proliferation after 8 h and cell viability after 24 h were analyzed by BrdU assay and FACS analysis, respectively. Gene expression analyses were carried out using the Agilent -microarray platform to indentify genes which displayed conjoint regulation following the addition of TRD in all cell lines. Candidate genes were subjected to Ingenuity Pathways Analysis and selected genes were validated by qRT-PCR and Western Blot. Results TRD 250 μM caused a significant inhibition of proliferation as well as apoptotic cell death in all cell lines. Among cell death associated genes with the strongest regulation in gene expression, we identified pro-apoptotic transcription factors (EGR1, ATF3) as well as genes involved in the ER stress response (PPP1R15A), in ubiquitination (TRAF6) and mitochondrial apoptotic pathways (PMAIP1). Conclusions This is the first conjoint analysis of potential target genes of TRD which was performed simultaneously in different malignant cell lines. The results indicate that TRD might be involved in different signal transduction pathways leading to apoptosis. PMID:21034493

  9. Green tea polyphenol induces significant cell death in human lung ...

    African Journals Online (AJOL)

    Green tea polyphenol induces significant cell death in human lung cancer cells. ... Tropical Journal of Pharmaceutical Research ... (8-OHdG), and apoptosis based on 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were evaluated in non-small cell lung cancer (NSCLC) cell lines, namely, H1155, ...

  10. Mechanical Stress Promotes Cisplatin-Induced Hepatocellular Carcinoma Cell Death

    Science.gov (United States)

    Riad, Sandra; Bougherara, Habiba

    2015-01-01

    Cisplatin (CisPt) is a commonly used platinum-based chemotherapeutic agent. Its efficacy is limited due to drug resistance and multiple side effects, thereby warranting a new approach to improving the pharmacological effect of CisPt. A newly developed mathematical hypothesis suggested that mechanical loading, when coupled with a chemotherapeutic drug such as CisPt and immune cells, would boost tumor cell death. The current study investigated the aforementioned mathematical hypothesis by exposing human hepatocellular liver carcinoma (HepG2) cells to CisPt, peripheral blood mononuclear cells, and mechanical stress individually and in combination. HepG2 cells were also treated with a mixture of CisPt and carnosine with and without mechanical stress to examine one possible mechanism employed by mechanical stress to enhance CisPt effects. Carnosine is a dipeptide that reportedly sequesters platinum-based drugs away from their pharmacological target-site. Mechanical stress was achieved using an orbital shaker that produced 300 rpm with a horizontal circular motion. Our results demonstrated that mechanical stress promoted CisPt-induced death of HepG2 cells (~35% more cell death). Moreover, results showed that CisPt-induced death was compromised when CisPt was left to mix with carnosine 24 hours preceding treatment. Mechanical stress, however, ameliorated cell death (20% more cell death). PMID:25685789

  11. Mechanical Stress Promotes Cisplatin-Induced Hepatocellular Carcinoma Cell Death

    Directory of Open Access Journals (Sweden)

    Laila Ziko

    2015-01-01

    Full Text Available Cisplatin (CisPt is a commonly used platinum-based chemotherapeutic agent. Its efficacy is limited due to drug resistance and multiple side effects, thereby warranting a new approach to improving the pharmacological effect of CisPt. A newly developed mathematical hypothesis suggested that mechanical loading, when coupled with a chemotherapeutic drug such as CisPt and immune cells, would boost tumor cell death. The current study investigated the aforementioned mathematical hypothesis by exposing human hepatocellular liver carcinoma (HepG2 cells to CisPt, peripheral blood mononuclear cells, and mechanical stress individually and in combination. HepG2 cells were also treated with a mixture of CisPt and carnosine with and without mechanical stress to examine one possible mechanism employed by mechanical stress to enhance CisPt effects. Carnosine is a dipeptide that reportedly sequesters platinum-based drugs away from their pharmacological target-site. Mechanical stress was achieved using an orbital shaker that produced 300 rpm with a horizontal circular motion. Our results demonstrated that mechanical stress promoted CisPt-induced death of HepG2 cells (~35% more cell death. Moreover, results showed that CisPt-induced death was compromised when CisPt was left to mix with carnosine 24 hours preceding treatment. Mechanical stress, however, ameliorated cell death (20% more cell death.

  12. Melatonin decreases cell proliferation, impairs myogenic differentiation and triggers apoptotic cell death in rhabdomyosarcoma cell lines.

    Science.gov (United States)

    Codenotti, Silvia; Battistelli, Michela; Burattini, Sabrina; Salucci, Sara; Falcieri, Elisabetta; Rezzani, Rita; Faggi, Fiorella; Colombi, Marina; Monti, Eugenio; Fanzani, Alessandro

    2015-07-01

    Melatonin is a small indole produced by the pineal gland and other tissues, and has numerous functions that aid in the maintenance of the whole body homeostasis, ranging from the regulation of circadian rhythms and sleep to protection from oxidative stress. Melatonin has also been reported to counteract cell growth and chemoresistance in different types of cancer. In the present study, we investigated the effects of exogenous melatonin administration on different human cell lines and primary mouse tumor cultures of rhabdomyosarcoma (RMS), the most frequent soft tissue sarcoma affecting childhood. The results showed that melatonin significantly affected the behavior of RMS cells, leading to inhibition of cell proliferation and impairment of myogenic differentiation followed by increased apoptotic cell death, as observed by immunoblotting analysis of apoptosis-related markers including Bax, Bcl-2 and caspase-3. Similar findings were observed using a combination of microscopy techniques, including scanning/transmission electron and confocal microscopy. Furthermore, melatonin in combination with doxorubicin or cisplatin, two compounds commonly used for the treatment of solid tumors, increased the sensitivity of RMS cells to apoptosis. These data indicated that melatonin may be effective in counteracting RMS tumor growth and chemoresistance.

  13. Cell division and death inhibit glassy behaviour of confluent tissues

    CERN Document Server

    Matoz-Fernandez, D A; Sknepnek, Rastko; Barrat, J L; Henkes, S

    2016-01-01

    We investigate the effects of cell division and apopotosis on collective dynamics in two-dimensional epithelial tissues. Our model includes three key ingredients observed across many epithelia, namely cell-cell adhesion, cell death and a cell division process that depends on the surrounding environment. We show a rich non-equilibrium phase diagram depending on the ratio of cell death to cell division and on the adhesion strength. For large apopotosis rates, cells die out and the tissue disintegrates. As the death rate decreases, however, we show, consecutively, the existence of a gas-like phase, a gel-like phase, and a dense confluent (tissue) phase. Most striking is the observation that the tissue is self-melting through its own internal activity, ruling out the existence of any glassy phase.

  14. Cell death induced by endoplasmic reticulum stress

    National Research Council Canada - National Science Library

    Iurlaro, Raffaella; Muñoz‐Pinedo, Cristina

    2016-01-01

    .... Many conditions that impose stress on cells, including hypoxia, starvation, infections and changes in secretory needs, challenge the folding capacity of the cell and promote endoplasmic reticulum stress...

  15. Activation-induced cell death of dendritic cells is dependent on sphingosine kinase 1

    Directory of Open Access Journals (Sweden)

    Anja eSchwiebs

    2016-04-01

    Full Text Available Sphingosine 1-phosphate (S1P is an immune modulatory lipid mediator and has been implicated in numerous pathophysiological processes. S1P is produced by sphingosine kinase 1 (Sphk1 and Sphk2. Dendritic cells (DCs are central for the direction of immune responses and crucially involved in autoimmunity and cancerogenesis. In this study we examined the function and survival of bone marrow-derived DCs under long-term inflammatory stimulation. We observed that differentiated cells undergo activation-induced cell death upon LPS stimulation with an increased metabolic activity shortly after stimulation, followed by a rapid activation of caspase 3 and subsequent augmented apoptosis. Importantly, we highlight a profound role of Sphk1 in secretion of inflammatory cytokines and survival of dendritic cells that might be mediated by a change in sphingolipid levels as well as by a change in STAT3 expression. Cell growth during differentiation of Sphk1-deficient cells treated with the functional S1P receptor antagonist FTYP was reduced. Importantly, in dendritic cells we did not observe a compensatory regulation of Sphk2 mRNA in Sphk1-deficient cells. Instead, we discovered a massive increase in Sphk1 mRNA concentration upon long-term stimulation with LPS in wild type cells that might function as an attempt to rescue from inflammation-caused cell death. Taken together, in this investigation we describe details of a crucial involvement of sphingolipids and Sphk1 in activation-induced cell death during long-term immunogenic activity of DCs that might play an important role in autoimmunity and might explain the differences in immune response observed in in vivo studies of Sphk1 modulation.

  16. Protein Kinase G facilitates EGFR-mediated cell death in MDA-MB-468 cells

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Nicole M.; Ceresa, Brian P., E-mail: brian.ceresa@louisville.edu

    2016-08-15

    The Epidermal Growth Factor Receptor (EGFR) is a transmembrane receptor tyrosine kinase with critical implications in cell proliferation, migration, wound healing and the regulation of apoptosis. However, the EGFR has been shown to be hyper-expressed in a number of human malignancies. The MDA-MB-468 metastatic breast cell line is one example of this. This particular cell line hyper-expresses the EGFR and undergoes EGFR-mediated apoptosis in response to EGF ligand. The goal of this study was to identify the kinases that could be potential intermediates for the EGFR-mediated induction of apoptosis intracellularly. After identifying Cyclic GMP-dependent Protein Kinase G (PKG) as a plausible intermediate, we wanted to determine the temporal relationship of these two proteins in the induction of apoptosis. We observed a dose-dependent decrease in MDA-MB-468 cell viability, which was co-incident with increased PKG activity as measured by VASPSer239 phosphorylation. In addition, we observed a dose dependent decrease in cell viability, as well as an increase in apoptosis, in response to two different PKG agonists, 8-Bromo-cGMP and 8-pCPT-cGMP. MDA-MB-468 cells with reduced PKG activity had attenuated EGFR-mediated apoptosis. These findings indicate that PKG does not induce cell death via transphosphorylation of the EGFR. Instead, PKG activity occurs following EGFR activation. Together, these data indicate PKG as an intermediary in EGFR-mediated cell death, likely via apoptotic pathway.

  17. Silicon does not mitigate cell death in cultured tobacco BY-2 cells subjected to salinity without ethylene emission.

    Science.gov (United States)

    Liang, Xiaolei; Wang, Huahua; Hu, Yanfeng; Mao, Lina; Sun, Lili; Dong, Tian; Nan, Wenbin; Bi, Yurong

    2015-02-01

    Silicon induces cell death when ethylene is suppressed in cultured tobacco BY-2 cells. There is a crosstalk between Si and ethylene signaling. Silicon (Si) is beneficial for plant growth. It alleviates both biotic and abiotic stresses in plants. How Si works in plants is still mysterious. This study investigates the mechanism of Si-induced cell death in tobacco BY-2 cell cultures when ethylene is suppressed. Results showed that K2SiO3 alleviated the damage of NaCl stress. Si treatment rapidly increased ethylene emission and the expression of ethylene biosynthesis genes. Treatments with Si + Ag and Si + aminooxyacetic acid (AOA, ethylene biosynthesis inhibitor) reduced the cell growth and increased cell damage. The treatment with Si + Ag induced hydrogen peroxide (H2O2) generation and ultimately cell death. Some nucleus of BY-2 cells treated with Si + Ag appeared TUNEL positive. The inhibition of H2O2 and nitric oxide (NO) production reduced the cell death rate induced by Si + Ag treatment. Si eliminated the up-regulation of alternative pathway by Ag. These data suggest that ethylene plays an important role in Si function in plants. Without ethylene, Si not only failed to enhance plant resistance, but also elevated H2O2 generation and further induced cell death in tobacco BY-2 cells.

  18. Control of cell proliferation, endoreduplication, cell size, and cell death by the retinoblastoma-related pathway in maize endosperm

    KAUST Repository

    Sabelli, Paolo A.

    2013-04-22

    The endospermof cereal grains is one of the most valuable products of modern agriculture. Cereal endosperm development comprises different phases characterized by mitotic cell proliferation, endoreduplication, the accumulation of storage compounds, and programmed cell death. Although manipulation of these processes could maximize grain yield, how they are regulated and integrated is poorly understood. We show that the Retinoblastoma-related (RBR) pathway controls key aspects of endosperm development in maize. Down-regulation of RBR1 by RNAi resulted in up-regulation of RBR3-type genes, as well as the MINICHROMOSOME MAINTENANCE 2-7 gene family and PROLIFERATING CELL NUCLEAR ANTIGEN, which encode essential DNA replication factors. Both the mitotic and endoreduplication cell cycles were stimulated. Developing transgenic endosperm contained 42-58% more cells and ~70% more DNA than wild type, whereas there was a reduction in cell and nuclear sizes. In addition, cell death was enhanced. The DNA content of mature endosperm increased 43% upon RBR1 downregulation, whereas storage protein content and kernel weight were essentially not affected. Down-regulation of both RBR1 and CYCLIN DEPENDENT KINASE A (CDKA);1 indicated that CDKA;1 is epistatic to RBR1 and controls endoreduplication through an RBR1- dependent pathway. However, the repressive activity of RBR1 on downstream targets was independent from CDKA;1, suggesting diversification of RBR1 activities. Furthermore, RBR1 negatively regulated CDK activity, suggesting the presence of a feedback loop. These results indicate that the RBR1 pathway plays a major role in regulation of different processes during maize endosperm development and suggest the presence of tissue/organlevel regulation of endosperm/seed homeostasis.

  19. Cationic polystyrene nanospheres induce autophagic cell death through the induction of endoplasmic reticulum stress

    Science.gov (United States)

    Chiu, Hui-Wen; Xia, Tian; Lee, Yu-Hsuan; Chen, Chun-Wan; Tsai, Jui-Chen; Wang, Ying-Jan

    2014-12-01

    Nanoparticles (NPs) have been used to produce a wide range of products that have applications in imaging and drug delivery in medicine. Due to their chemical stability, well-controlled sizes and surface charges, polystyrene (PS) NPs have been developed as biosensors and drug delivery carriers. However, the possible adverse biological effects and underlying mechanisms are still unclear. Recently, autophagy has been implicated in the regulation of cell death. In this study, we evaluated a library of PS NPs with different surface charges. We found that NH2-labeled polystyrene (NH2-PS) nanospheres were highly toxic with enhanced uptake in macrophage (RAW 264.7) and lung epithelial (BEAS-2B) cells. Furthermore, NH2-PS could induce autophagic cell death. NH2-PS increased autophagic flux due to reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress caused by misfolded protein aggregation. The inhibition of ER stress decreased cytotoxicity and autophagy in the NH2-PS-treated cells. In addition, the Akt/mTOR and AMPK signaling pathways were involved in the regulation of NH2-PS-triggered autophagic cell death. These results suggest an important role of autophagy in cationic NP-induced cell death and provide mechanistic insights into the inhibition of the toxicity and safe material design.Nanoparticles (NPs) have been used to produce a wide range of products that have applications in imaging and drug delivery in medicine. Due to their chemical stability, well-controlled sizes and surface charges, polystyrene (PS) NPs have been developed as biosensors and drug delivery carriers. However, the possible adverse biological effects and underlying mechanisms are still unclear. Recently, autophagy has been implicated in the regulation of cell death. In this study, we evaluated a library of PS NPs with different surface charges. We found that NH2-labeled polystyrene (NH2-PS) nanospheres were highly toxic with enhanced uptake in macrophage (RAW 264.7) and lung

  20. Thioredoxin Reductase Mediates Cell Death Effects of the Combination of Beta Interferon and Retinoic Acid

    Science.gov (United States)

    Hofman, Edward R.; Boyanapalli, Madanamohan; Lindner, Daniel J.; Weihua, Xiao; Hassel, Bret A.; Jagus, Rosemary; Gutierrez, Peter L.; Kalvakolanu, Dhananjaya V.

    1998-01-01

    Interferons (IFNs) and retinoids are potent biological response modifiers. By using JAK-STAT pathways, IFNs regulate the expression of genes involved in antiviral, antitumor, and immunomodulatory actions. Retinoids exert their cell growth-regulatory effects via nuclear receptors, which also function as transcription factors. Although these ligands act through distinct mechanisms, several studies have shown that the combination of IFNs and retinoids synergistically inhibits cell growth. We have previously reported that IFN-β–all-trans-retinoic acid (RA) combination is a more potent growth suppressor of human tumor xenografts in vivo than either agent alone. Furthermore, the IFN-RA combination causes cell death in several tumor cell lines in vitro. However, the molecular basis for these growth-suppressive actions is unknown. It has been suggested that certain gene products, which mediate the antiviral actions of IFNs, are also responsible for the antitumor actions of the IFN-RA combination. However, we did not find a correlation between their activities and cell death. Therefore, we have used an antisense knockout approach to directly identify the gene products that mediate cell death and have isolated several genes associated with retinoid-IFN-induced mortality (GRIM). In this investigation, we characterized one of the GRIM cDNAs, GRIM-12. Sequence analysis suggests that the GRIM-12 product is identical to human thioredoxin reductase (TR). TR is posttranscriptionally induced by the IFN-RA combination in human breast carcinoma cells. Overexpression of GRIM-12 causes a small amount of cell death and further enhances the susceptibility of cells to IFN-RA-induced death. Dominant negative inhibitors directed against TR inhibit its cell death-inducing functions. Interference with TR enzymatic activity led to growth promotion in the presence of the IFN-RA combination. Thus, these studies identify a novel function for TR in cell growth regulation. PMID:9774665

  1. Neuronal death after perinatal cerebral hypoxia-ischemia: Focus on autophagy-mediated cell death.

    Science.gov (United States)

    Descloux, C; Ginet, V; Clarke, P G H; Puyal, J; Truttmann, A C

    2015-10-01

    Neonatal hypoxic-ischemic encephalopathy is a critical cerebral event occurring around birth with high mortality and neurological morbidity associated with long-term invalidating sequelae. In view of the great clinical importance of this condition and the lack of very efficacious neuroprotective strategies, it is urgent to better understand the different cell death mechanisms involved with the ultimate aim of developing new therapeutic approaches. The morphological features of three different cell death types can be observed in models of perinatal cerebral hypoxia-ischemia: necrotic, apoptotic and autophagic cell death. They may be combined in the same dying neuron. In the present review, we discuss the different cell death mechanisms involved in neonatal cerebral hypoxia-ischemia with a special focus on how autophagy may be involved in neuronal death, based: (1) on experimental models of perinatal hypoxia-ischemia and stroke, and (2) on the brains of human neonates who suffered from neonatal hypoxia-ischemia. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Cell wall dynamics modulate acetic acid-induced apoptotic cell death of Saccharomyces cerevisiae

    Science.gov (United States)

    Rego, António; Duarte, Ana M.; Azevedo, Flávio; Sousa, Maria J.; Côrte-Real, Manuela; Chaves, Susana R.

    2014-01-01

    Acetic acid triggers apoptotic cell death in Saccharomyces cerevisiae, similar to mammalian apoptosis. To uncover novel regulators of this process, we analyzed whether impairing MAPK signaling affected acetic acid-induced apoptosis and found the mating-pheromone response and, especially, the cell wall integrity pathways were the major mediators, especially the latter, which we characterized further. Screening downstream effectors of this pathway, namely targets of the transcription factor Rlm1p, highlighted decreased cell wall remodeling as particularly important for acetic acid resistance. Modulation of cell surface dynamics therefore emerges as a powerful strategy to increase acetic acid resistance, with potential application in industrial fermentations using yeast, and in biomedicine to exploit the higher sensitivity of colorectal carcinoma cells to apoptosis induced by acetate produced by intestinal propionibacteria. PMID:28357256

  3. Related F-box proteins control cell death in Caenorhabditis elegans and human lymphoma

    Science.gov (United States)

    Chiorazzi, Michael; Rui, Lixin; Yang, Yandan; Ceribelli, Michele; Tishbi, Nima; Maurer, Carine W.; Ranuncolo, Stella M.; Zhao, Hong; Xu, Weihong; Chan, Wing-Chung C.; Jaffe, Elaine S.; Gascoyne, Randy D.; Campo, Elias; Rosenwald, Andreas; Ott, German; Delabie, Jan; Rimsza, Lisa M.; Shaham, Shai; Staudt, Louis M.

    2013-01-01

    Cell death is a common metazoan cell fate, and its inactivation is central to human malignancy. In Caenorhabditis elegans, apoptotic cell death occurs via the activation of the caspase CED-3 following binding of the EGL-1/BH3-only protein to the antiapoptotic CED-9/BCL2 protein. Here we report a major alternative mechanism for caspase activation in vivo involving the F-box protein DRE-1. DRE-1 functions in parallel to EGL-1, requires CED-9 for activity, and binds to CED-9, suggesting that DRE-1 promotes apoptosis by inactivating CED-9. FBXO10, a human protein related to DRE-1, binds BCL2 and promotes its degradation, thereby initiating cell death. Moreover, some human diffuse large B-cell lymphomas have inactivating mutations in FBXO10 or express FBXO10 at low levels. Our results suggest that DRE-1/FBXO10 is a conserved regulator of apoptosis. PMID:23431138

  4. Control of adult neurogenesis by programmed cell death in the mammalian brain.

    Science.gov (United States)

    Ryu, Jae Ryun; Hong, Caroline Jeeyeon; Kim, Joo Yeon; Kim, Eun-Kyoung; Sun, Woong; Yu, Seong-Woon

    2016-04-21

    The presence of neural stem cells (NSCs) and the production of new neurons in the adult brain have received great attention from scientists and the public because of implications to brain plasticity and their potential use for treating currently incurable brain diseases. Adult neurogenesis is controlled at multiple levels, including proliferation, differentiation, migration, and programmed cell death (PCD). Among these, PCD is the last and most prominent process for regulating the final number of mature neurons integrated into neural circuits. PCD can be classified into apoptosis, necrosis, and autophagic cell death and emerging evidence suggests that all three may be important modes of cell death in neural stem/progenitor cells. However, the molecular mechanisms that regulate PCD and thereby impact the intricate balance between self-renewal, proliferation, and differentiation during adult neurogenesis are not well understood. In this comprehensive review, we focus on the extent, mechanism, and biological significance of PCD for the control of adult neurogenesis in the mammalian brain. The role of intrinsic and extrinsic factors in the regulation of PCD at the molecular and systems levels is also discussed. Adult neurogenesis is a dynamic process, and the signals for differentiation, proliferation, and death of neural progenitor/stem cells are closely interrelated. A better understanding of how adult neurogenesis is influenced by PCD will help lead to important insights relevant to brain health and diseases.

  5. Paraptosis cell death induction by the thiamine analog benfotiamine in leukemia cells.

    Directory of Open Access Journals (Sweden)

    Naomi Sugimori

    Full Text Available Benfotiamine is a synthetic thiamine analogue that stimulates transketolase, a cellular enzyme essential for glucose metabolism. Currently, benfotiamine is used to treat diabetic neuropathy. We recently reported that oral benfotiamine induced a temporary but remarkable recovery from acute myeloid leukemia in an elderly patient who was ineligible for standard chemotherapy due to dementia and renal failure. In the present study we present evidences that benfotiamine possess antitumor activity against leukemia cells. In a panel of nine myeloid leukemia cell lines benfotiamine impaired the viability of HL-60, NB4, K562 and KG1 cells and also inhibited the growing of primary leukemic blasts. The antitumor activity of benfotiamine is not mediated by apoptosis, necrosis or autophagy, but rather occurs though paraptosis cell death induction. Mechanistic studies revealed that benfotiamine inhibited the activity of constitutively active ERK1/2 and concomitantly increased the phosphorylation of JNK1/2 kinase in leukemic cells. In addition, benfotiamine induced the down regulation of the cell cycle regulator CDK3 which resulted in G1 cell cycle arrest in the sensitive leukemic cells. Moreover, combination index studies showed that benfotiamine enhanced the antiproliferative activities of cytarabine against leukemia cells. These findings suggest that benfotiamine has antitumor therapeutic potential.

  6. Activation of Extracellular Signal-Regulated Protein Kinases 1 and 2 (ERK1/2 by Free Fatty Acid Receptor 1 (FFAR1/GPR40 Protects from Palmitate-Induced Beta Cell Death, but Plays no Role in Insulin Secretion

    Directory of Open Access Journals (Sweden)

    Madhura Panse

    2015-03-01

    Full Text Available Aims: GPR40/FFAR1 mediates palmitate-induced stimulation of insulin secretion but its involvement in lipotoxicity is controversial. Our previous observations suggest that FFAR1/GPR40 agonists protect against lipotoxicity although the underlying mechanism remains elusive. The present study examines the role of ERK1/2 and GPR40/FFAR1 in palmitate-induced stimulation of insulin secretion and beta cell death. Methods: Insulin secretion of INS-1E cells was measured by radioimmunoassay. Protein phosphorylation was examined on Western blots. Apoptosis was assessed by TUNEL staining. Results: Palmitate and the GPR40/FFAR1 agonist TUG-469 increased phosphorylation of ERK1/2 at low (2.8 mmol/L and high (12 mmol/L glucose but stimulated insulin secretion only at high glucose. The MEK1 inhibitor PD98059 significantly reduced phosphorylation of ERK1/2 but did not reverse the stimulation of secretion induced by glucose, palmitate or TUG-469. PD98059 rather augmented glucose-induced secretion. Prolonged exposure to palmitate stimulated apoptosis, an effect counteracted by TUG-469. PD98059 accentuated palmitate-induced apoptosis and reversed TUG-469-mediated inhibition of cell death. Conclusions: Activation of ERK1/2 by palmitate and GPR40/FFAR1 agonist correlates neither with stimulation of insulin secretion nor with induction of apoptosis. The results suggest a significant anti-apoptotic role of ERK1/2 under conditions of lipotoxicity.

  7. Lipid constituents in oligodendroglial cells alter susceptibility to H2O2-induced apoptotic cell death via ERK activation.

    Science.gov (United States)

    Brand, A; Gil, S; Seger, R; Yavin, E

    2001-02-01

    The present work examines the effect of membrane lipid composition on activation of extracellular signal-regulated protein kinases (ERK) and cell death following oxidative stress. When subjected to 50 microM docosahexaenoic acid (DHA, 22 : 6 n-3), cellular phospholipids of OLN 93 cells, a clonal line of oligodendroglia origin low in DHA, were enriched with this polyunsaturated fatty acid. In the presence of 1 mM N,N-dimethylethanolamine (dEa) a new phospholipid species analog was formed in lieu of phosphatidylcholine. Exposure of DHA-enriched cells to 0.5 mM H2O2, caused sustained activation of ERK up to 24 h. At this time massive apoptotic cell death was demonstrated by ladder and TUNEL techniques. H2O2-induced stress applied to dEa or DHA/dEa co-supplemented cells showed only a transient ERK activation and no cell death after 24 h. Moreover, while ERK was rapidly translocated into the nucleus in DHA-enriched cells, dEa supplements completely blocked ERK nuclear translocation. This study suggests that H2O2-induced apoptotic cell death is associated with prolonged ERK activation and nuclear translocation in DHA-enriched OLN 93 cells, while both phenomena are prevented by dEa supplements. Thus, the membrane lipid composition ultimately modulates ERK activation and translocation and therefore can promote or prevent apoptotic cell death.

  8. Mitochondrial impairment induces excitotoxic death in cerebellar granule cells.

    Science.gov (United States)

    Bobba, Antonella; Atlante, Anna; Azzariti, Amalia; Sgaramella, Giuseppe; Calissano, Pietro; Marra, Ersilia

    2004-06-01

    A close relationship links mitochondria to cell death with mitochondrial function-impairment considered a major biochemical event in the process of both apoptosis and necrosis. We have used different inhibitors of oxidative phosphorylation, i.e. mitochondrial respiratory chain and ATP synthesis inhibitors, and an uncoupler to investigate the mode of cell death caused by these compounds in cerebellar granule cells. This study shows that in cultured cerebellar granule cells either oxidative phosphorylation inhibitors or uncoupler induce an excitotoxic-like reaction which is mediated by activation of NMDA receptors and is likely due to the release of glutamate. Consistently, survival may occur if the toxic action of glutamate is prevented.

  9. Cell volume regulation: physiology and pathophysiology

    DEFF Research Database (Denmark)

    Lambert, I H; Hoffmann, E K; Pedersen, Stine Helene Falsig

    2008-01-01

    not only under physiological conditions, e.g. following accumulation of nutrients, during epithelial absorption/secretion processes, following hormonal/autocrine stimulation, and during induction of apoptosis, but also under pathophysiological conditions, e.g. hypoxia, ischaemia and hyponatremia....../hypernatremia. On the other hand, it has recently become clear that an increase or reduction in cell volume can also serve as a specific signal in the regulation of physiological processes such as transepithelial transport, cell migration, proliferation and death. Although the mechanisms by which cell volume perturbations...... are sensed are still far from clear, significant progress has been made with respect to the nature of the sensors, transducers and effectors that convert a change in cell volume into a physiological response. In the present review, we summarize recent major developments in the field, and emphasize...

  10. PKC activation induces inflammatory response and cell death in human bronchial epithelial cells.

    Directory of Open Access Journals (Sweden)

    Hyunhee Kim

    Full Text Available A variety of airborne pathogens can induce inflammatory responses in airway epithelial cells, which is a crucial component of host defence. However, excessive inflammatory responses and chronic inflammation also contribute to different diseases of the respiratory system. We hypothesized that the activation of protein kinase C (PKC is one of the essential mechanisms of inflammatory response in airway epithelial cells. In the present study, we stimulated human bronchial lung epithelial (BEAS-2B cells with the phorbol ester Phorbol 12, 13-dibutyrate (PDBu, and examined gene expression profile using microarrays. Microarray analysis suggests that PKC activation induced dramatic changes in gene expression related to multiple cellular functions. The top two interaction networks generated from these changes were centered on NFκB and TNF-α, which are two commonly known pathways for cell death and inflammation. Subsequent tests confirmed the decrease in cell viability and an increase in the production of various cytokines. Interestingly, each of the increased cytokines was differentially regulated at mRNA and/or protein levels by different sub-classes of PKC isozymes. We conclude that pathological cell death and cytokine production in airway epithelial cells in various situations may be mediated through PKC related signaling pathways. These findings suggest that PKCs can be new targets for treatment of lung diseases.

  11. Eclalbasaponin II induces autophagic and apoptotic cell death in human ovarian cancer cells

    Directory of Open Access Journals (Sweden)

    Yoon Jin Cho

    2016-09-01

    Full Text Available Triterpenoids echinocystic acid and its glycosides, isolated from several Eclipta prostrata, have been reported to possess various biological activities such as anti-inflammatory, anti-bacterial, and anti-diabetic activity. However, the cytotoxicity of the triterpenoids in human cancer cells and their molecular mechanism of action are poorly understood. In the present study, we found that eclalbasaponin II with one glucose moiety has potent cytotoxicity in three ovarian cancer cells and two endometrial cancer cells compared to an aglycone echinocystic acid and eclalbasaponin I with two glucose moiety. Eclalbasaponin II treatment dose-dependently increased sub G1 population. Annexin V staining revealed that eclalbasaponin II induced apoptosis in SKOV3 and A2780 ovarian cancer cells. In addition, eclalbasaponin II-induced cell death was associated with characteristics of autophagy; an increase in acidic vesicular organelle content and elevation of the levels of LC3-II. Interestingly, autophagy inhibitor BaF1 suppressed the eclalbasaponin II-induced apoptosis. Moreover, eclalbasaponin II activated JNK and p38 signaling and inhibited the mTOR signaling. We further demonstrated that pre-treatment with a JNK and p38 inhibitor and mTOR activator attenuated the eclalbasaponin II-induced autophagy. This suggests that eclalbasaponin II induces apoptotic and autophagic cell death through the regulation of JNK, p38, and mTOR signaling in human ovarian cancer cells.

  12. Macrophage alternative activation confers protection against lipotoxicity-induced cell death

    Directory of Open Access Journals (Sweden)

    Lingling Dai

    2017-10-01

    Conclusions: Our data suggest that ATM cell death is closely linked to metabolic inflammation. Within WAT where concentrations of free fatty acids fluctuate, M2 polarization regulated by the Stat6-Ppar axis enhances ATM's tolerance to lipid-mediated stress, thereby maintaining the homeostatic state.

  13. EBV and Apoptosis: The Viral Master Regulator of Cell Fate?

    Science.gov (United States)

    Kelly, Gemma L.

    2017-01-01

    Epstein–Barr virus (EBV) was first discovered in cells from a patient with Burkitt lymphoma (BL), and is now known to be a contributory factor in 1–2% of all cancers, for which there are as yet, no EBV-targeted therapies available. Like other herpesviruses, EBV adopts a persistent latent infection in vivo and only rarely reactivates into replicative lytic cycle. Although latency is associated with restricted patterns of gene expression, genes are never expressed in isolation; always in groups. Here, we discuss (1) the ways in which the latent genes of EBV are known to modulate cell death, (2) how these mechanisms relate to growth transformation and lymphomagenesis, and (3) how EBV genes cooperate to coordinately regulate key cell death pathways in BL and lymphoblastoid cell lines (LCLs). Since manipulation of the cell death machinery is critical in EBV pathogenesis, understanding the mechanisms that underpin EBV regulation of apoptosis therefore provides opportunities for novel therapeutic interventions. PMID:29137176

  14. Exposure to low-dose X-rays promotes peculiar autophagic cell death in Drosophila melanogaster, an effect that can be regulated by the inducible expression of Hml dsRNA

    Energy Technology Data Exchange (ETDEWEB)

    Kanao, Tomoko [Department of Radiological Sciences, International University of Health and Welfare, Kitakanemaru 2600-1, Ohtawara-shi, Tochigi-ken 324-8501 (Japan); Miyachi, Yukihisa [Department of Radiological Sciences, International University of Health and Welfare, Kitakanemaru 2600-1, Ohtawara-shi, Tochigi-ken 324-8501 (Japan)]. E-mail: ymiyachi@iuhw.ac.jp

    2006-03-20

    We previously reported that to induce an early emergence effect with low-dose X-irradiation in Drosophila, exposure during the prepupae stage is necessary. The present study examined the mechanism by which low-dose radiation rapidly eliminates larval cells and activates the formation of the imaginal discs during metamorphosis. Upon exposure to 0.5 Gy X-rays at 2 h after puparium formation (APF), the larval salivary glands swelled and were surrounded by remarkably thick structures containing an acid phosphatase (Acph) enzyme, implicating a peculiar autophagic cell death. TUNEL staining revealed the presence of DNA fragmentations compared with cells from sham controls which remained unchanged until 12 h APF. Additionally, the salivary glands of exposed flies were completely destroyed by 10 h APF. Furthermore, exposure to 0.5 Gy X-rays also facilitated the activity of the engulfment function of dendritic cells (DCs); they were generated in the larval salivary glands, engulfed the cell corpses and finally moved to the fat body. Data from an experiment demonstrating the inducible expression of Hml double-stranded RNA (dsRNA) indicate that a slow rate of engulfment of larval cells results in a longer time to emergence. Thus, the animals subjected to low-dose X-rays activated autophagic processes, resulting in significantly faster adult eclosion.

  15. Role of SOCE architects STIM and Orai proteins in Cell Death.

    Science.gov (United States)

    Tanwar, Jyoti; Motiani, Rajender K

    2017-06-09

    Calcium (Ca2+) signaling plays a critical role in regulating plethora of cellular functions including cell survival, proliferation and migration. The perturbations in cellular Ca2+ homeostasis can lead to cell death either by activating autophagic pathways or through induction of apoptosis. Endoplasmic reticulum (ER) is the major storehouse of Ca2+ within cells and a number of physiological agonists mediate ER Ca2+ release by activating IP3 receptors (IP3R). This decrease in ER Ca2+ levels is sensed by STIM, which physically interacts and activates plasma membrane Ca2+ selective Orai channels. Emerging literature implicates a key role for STIM1, STIM2, Orai1 and Orai3 in regulating both cell survival and death pathways. In this review, we will retrospect the work highlighting the role of STIM and Orai homologs in regulating cell death signaling. We will further discuss the rationales that could explain the dual role of STIM and Orai proteins in regulating cell fate decisions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The MST/Hippo Pathway and Cell Death: A Non-Canonical Affair.

    Science.gov (United States)

    Fallahi, Emma; O'Driscoll, Niamh A; Matallanas, David

    2016-06-17

    The MST/Hippo signalling pathway was first described over a decade ago in Drosophila melanogaster and the core of the pathway is evolutionary conserved in mammals. The mammalian MST/Hippo pathway regulates organ size, cell proliferation and cell death. In addition, it has been shown to play a central role in the regulation of cellular homeostasis and it is commonly deregulated in human tumours. The delineation of the canonical pathway resembles the behaviour of the Hippo pathway in the fly where the activation of the core kinases of the pathway prevents the proliferative signal mediated by the key effector of the pathway YAP. Nevertheless, several lines of evidence support the idea that the mammalian MST/Hippo pathway has acquired new features during evolution, including different regulators and effectors, crosstalk with other essential signalling pathways involved in cellular homeostasis and the ability to actively trigger cell death. Here we describe the current knowledge of the mechanisms that mediate MST/Hippo dependent cell death, especially apoptosis. We include evidence for the existence of complex signalling networks where the core proteins of the pathway play a central role in controlling the balance between survival and cell death. Finally, we discuss the possible involvement of these signalling networks in several human diseases such as cancer, diabetes and neurodegenerative disorders.

  17. The silencing of adenine nucleotide translocase isoform 1 induces oxidative stress and programmed cell death in ADF human glioblastoma cells.

    Science.gov (United States)

    Lena, Annalisa; Rechichi, Mariarosa; Salvetti, Alessandra; Vecchio, Donatella; Evangelista, Monica; Rainaldi, Giuseppe; Gremigni, Vittorio; Rossi, Leonardo

    2010-07-01

    Adenine nucleotide translocases (ANTs) are multitask proteins involved in several aspects of cell metabolism, as well as in the regulation of cell death/survival processes. We investigated the role played by ANT isoforms 1 and 2 in the growth of a human glioblastoma cell line (ADF cells). The silencing of ANT2 isoform, by small interfering RNA, did not produce significant changes in ADF cell viability. By contrast, the silencing of ANT1 isoform strongly reduced ADF cell viability by inducing a non-apoptotic cell death process resembling paraptosis. We demonstrated that cell death induced by ANT1 depletion cannot be ascribed to the loss of the ATP/ADP exchange function of this protein. By contrast, our findings indicate that ANT1-silenced cells experience oxidative stress, thus allowing us to hypothesize that the effect of ANT1-silencing on ADF is mediated by the loss of the ANT1 uncoupling function. Several studies ascribe a pro-apoptotic role to ANT1 as a result of the observation that ANT1 overexpression sensitizes cells to mitochondrial depolarization or to apoptotic stimuli. In the present study, we demonstrate that, despite its pro-apoptotic function at a high expression level, the reduction of ANT1 density below a physiological baseline impairs fundamental functions of this protein in ADF cells, leading them to undertake a cell death process.

  18. Entamoeba histolytica induces cell death of HT29 colonic epithelial cells via NOX1-derived ROS.

    Science.gov (United States)

    Kim, Kyeong Ah; Kim, Ju Young; Lee, Young Ah; Min, Arim; Bahk, Young Yil; Shin, Myeong Heon

    2013-02-01

    Entamoeba histolytica, which causes amoebic colitis and occasionally liver abscess in humans, is able to induce host cell death. However, signaling mechanisms of colon cell death induced by E. histolytica are not fully elucidated. In this study, we investigated the signaling role of NOX in cell death of HT29 colonic epithelial cells induced by E. histolytica. Incubation of HT29 cells with amoebic trophozoites resulted in DNA fragmentation that is a hallmark of apoptotic cell death. In addition, E. histolytica generate intracellular reactive oxygen species (ROS) in a contact-dependent manner. Inhibition of intracellular ROS level with treatment with DPI, an inhibitor of NADPH oxidases (NOXs), decreased Entamoeba-induced ROS generation and cell death in HT29 cells. However, pan-caspase inhibitor did not affect E. histolytica-induced HT29 cell death. In HT29 cells, catalytic subunit NOX1 and regulatory subunit Rac1 for NOX1 activation were highly expressed. We next investigated whether NADPH oxidase 1 (NOX1)-derived ROS is closely associated with HT29 cell death induced by E. histolytica. Suppression of Rac1 by siRNA significantly inhibited Entamoeba-induced cell death. Moreover, knockdown of NOX1 by siRNA, effectively inhibited E. histolytica-triggered DNA fragmentation in HT29 cells. These results suggest that NOX1-derived ROS is required for apoptotic cell death in HT29 colon epithelial cells induced by E. histolytica.

  19. Cardiac Glycoside Glucoevatromonoside Induces Cancer Type-Specific Cell Death

    Directory of Open Access Journals (Sweden)

    Naira F. Z. Schneider

    2018-03-01

    Full Text Available Cardiac glycosides (CGs are natural compounds used traditionally to treat congestive heart diseases. Recent investigations repositioned CGs as potential anticancer agents. To discover novel cytotoxic CG scaffolds, we selected the cardenolide glucoevatromonoside (GEV out of 46 CGs for its low nanomolar anti-lung cancer activity. GEV presented reduced toxicity toward non-cancerous cell types (lung MRC-5 and PBMC and high-affinity binding to the Na+/K+-ATPase α subunit, assessed by computational docking. GEV-induced cell death was caspase-independent, as investigated by a multiparametric approach, and culminates in severe morphological alterations in A549 cells, monitored by transmission electron microscopy, live cell imaging and flow cytometry. This non-canonical cell death was not preceded or accompanied by exacerbation of autophagy. In the presence of GEV, markers of autophagic flux (e.g. LC3I-II conversion were impacted, even in presence of bafilomycin A1. Cell death induction remained unaffected by calpain, cathepsin, parthanatos, or necroptosis inhibitors. Interestingly, GEV triggered caspase-dependent apoptosis in U937 acute myeloid leukemia cells, witnessing cancer-type specific cell death induction. Differential cell cycle modulation by this CG led to a G2/M arrest, cyclin B1 and p53 downregulation in A549, but not in U937 cells. We further extended the anti-cancer potential of GEV to 3D cell culture using clonogenic and spheroid formation assays and validated our findings in vivo by zebrafish xenografts. Altogether, GEV shows an interesting anticancer profile with the ability to exert cytotoxic effects via induction of different cell death modalities.

  20. BID links ferroptosis to mitochondrial cell death pathways

    Directory of Open Access Journals (Sweden)

    Sandra Neitemeier

    2017-08-01

    In the present study, we find that erastin-induced ferroptosis in neuronal cells was accompanied by BID transactivation to mitochondria, loss of mitochondrial membrane potential, enhanced mitochondrial fragmentation and reduced ATP levels. These hallmarks of mitochondrial demise are also established features of oxytosis, a paradigm of cell death induced by Xc- inhibition by millimolar concentrations of glutamate. Bid knockout using CRISPR/Cas9 approaches preserved mitochondrial integrity and function, and mediated neuroprotective effects against both, ferroptosis and oxytosis. Furthermore, the BID-inhibitor BI-6c9 inhibited erastin-induced ferroptosis, and, in turn, the ferroptosis inhibitors ferrostatin-1 and liproxstatin-1 prevented mitochondrial dysfunction and cell death in the paradigm of oxytosis. These findings show that mitochondrial transactivation of BID links ferroptosis to mitochondrial damage as the final execution step in this paradigm of oxidative cell death.

  1. Omega-3 docosahexaenoic acid induces pyroptosis cell death in triple-negative breast cancer cells.

    Science.gov (United States)

    Pizato, Nathalia; Luzete, Beatriz Christina; Kiffer, Larissa Fernanda Melo Vasconcelos; Corrêa, Luís Henrique; de Oliveira Santos, Igor; Assumpção, José Antônio Fagundes; Ito, Marina Kiyomi; Magalhães, Kelly Grace

    2018-01-31

    The implication of inflammation in pathophysiology of several type of cancers has been under intense investigation. Omega-3 fatty acids can modulate inflammation and present anticancer effects, promoting cancer cell death. Pyroptosis is an inflammation related cell death and so far, the function of docosahexaenoic acid (DHA) in pyroptosis cell death has not been described. This study investigated the role of DHA in triggering pyroptosis activation in breast cancer cells. MDA-MB-231 breast cancer cells were supplemented with DHA and inflammation cell death was analyzed. DHA-treated breast cancer cells triggered increased caspase-1and gasdermin D activation, enhanced IL-1β secretion, translocated HMGB1 towards the cytoplasm, and membrane pore formation when compared to untreated cells, suggesting DHA induces pyroptosis programmed cell death in breast cancer cells. Moreover, caspase-1 inhibitor (YVAD) could protect breast cancer cells from DHA-induced pyroptotic cell death. In addition, membrane pore formation showed to be a lysosomal damage and ROS formation-depended event in breast cancer cells. DHA triggered pyroptosis cell death in MDA-MB-231by activating several pyroptosis markers in these cells. This is the first study that shows the effect of DHA triggering pyroptosis programmed cell death in breast cancer cells and it could improve the understanding of the omega-3 supplementation during breast cancer treatment.

  2. Substrate curvature regulates cell migration.

    Science.gov (United States)

    He, Xiuxiu; Jiang, Yi

    2017-05-23

    Cell migration is essential in many aspects of biology. Many basic migration processes, including adhesion, membrane protrusion and tension, cytoskeletal polymerization, and contraction, have to act in concert to regulate cell migration. At the same time, substrate topography modulates these processes. In this work, we study how substrate curvature at micrometer scale regulates cell motility. We have developed a 3D mechanical model of single cell migration and simulated migration on curved substrates with different curvatures. The simulation results show that cell migration is more persistent on concave surfaces than on convex surfaces. We have further calculated analytically the cell shape and protrusion force for cells on curved substrates. We have shown that while cells spread out more on convex surfaces than on concave ones, the protrusion force magnitude in the direction of migration is larger on concave surfaces than on convex ones. These results offer a novel biomechanical explanation to substrate curvature regulation of cell migration: geometric constrains bias the direction of the protrusion force and facilitates persistent migration on concave surfaces.

  3. Caspase-2 mediates a Brucella abortus RB51-induced hybrid cell death having features of apoptosis and pyroptosis

    Directory of Open Access Journals (Sweden)

    Denise Nicole Bronner

    2013-11-01

    Full Text Available Programmed cell death (PCD can play a crucial role in tuning the immune response to microbial infection. Although PCD can occur in different forms, all are mediated by a family of proteases called caspases. Caspase-2 is the most conserved caspase; however its function in cell death is ill-defined. Previously we demonstrated that live attenuated cattle vaccine strain Brucella abortus RB51 induces caspase-2-mediated PCD of infected macrophages. However, the mechanism of caspase-2-mediated cell death pathway remained unclear. In this study, we found that caspase-2 mediated proinflammatory cell death of RB51-infected macrophages and regulated many genes in different PCD pathways. We show that the activation of proapoptotic caspases-3 and -8 was dependent upon caspase-2. Caspase-2 regulated mitochondrial cytochrome c release and TNFα production, both of which are known to activate caspase-3 and caspase-8, respectively. In addition to TNFα, RB51-induced caspase-1 and IL-1β production was also driven by caspase-2-mediated mitochondrial dysfunction. Interestingly, pore formation, a phenomenon commonly associated with caspase-1-mediated pyroptosis, occurred; however it did not contribute to RB51-induced proinflammatory cell death. Our data suggest that caspase-2 acts as an initiator caspase that mediates a novel RB51-induced hybrid cell death that simulates but differs from typical apoptosis and pyroptosis. The initiator role of the caspase-2-mediated cell death was also conserved in cellular stress-induced cell death of macrophages treated with etoposide, naphthalene, or anti-Fas. Caspase-2 also regulated caspase-3 and -8 activation, as well as cell death in macrophages treated with each of the three reagents. Taken together, our data has demonstrated that caspase-2 can play an important role in mediating a proinflammatory response and a hybrid cell death that demonstrates features of both apoptosis and pyroptosis.

  4. Green tea polyphenol induces significant cell death in human lung ...

    African Journals Online (AJOL)

    Green tea polyphenol induces significant cell death in human lung cancer cells. Jie Huang, Fa-jiu Li, Shi Chen, Yi Shi, Xiao-jiang Wang, Chuan-hai Wang, Qing- ..... method for the determination of green and black tea polyphenols in biomatrices by high-performance liquid chromatography with coulometric array detection.

  5. Palladium induced oxidative stress and cell death in normal ...

    African Journals Online (AJOL)

    Pretreatment of hepatocytes with ROS scavengers and MPT pore sealing agents reduced cell death which explains the role of oxidative stress and mitochondrial pathway of ROS formation in Pd hepatocytes cell toxicity. Overall, the results have distinctly determined the mechanism by which Pd-induced toxicity in the ...

  6. Cell death by mitotic catastrophe: a molecular definition

    NARCIS (Netherlands)

    Castedo, M.; Perfettini, J.-L.; Roumier, T.; Andreau, K.; Medema, R.H.; Kroemer, G.

    2004-01-01

    The current literature is devoid of a clearcut definition of mitotic catastrophe, a type of cell death that occurs during mitosis. Here, we propose that mitotic catastrophe results from a combination of deficient cell-cycle checkpoints (in particular the DNA structure checkpoints and the spindle

  7. Cell volume regulation in epithelial physiology and cancer

    DEFF Research Database (Denmark)

    Pedersen, Stine Helene Falsig; Hoffmann, Else Kay; Novak, Ivana

    2013-01-01

    regulation both rely on the spatially and temporally coordinated function of ion channels and transporters. In healthy epithelia, specific ion channels/transporters localize to the luminal and basolateral membranes, contributing to functional epithelial polarity. In pathophysiological processes...... such as cancer, transepithelial and cell volume regulatory ion transport are dys-regulated. Furthermore, epithelial architecture and coordinated ion transport function are lost, cell survival/death balance is altered, and new interactions with the stroma arise, all contributing to drug resistance. Since altered...

  8. Programmed Necrosis: A Prominent Mechanism of Cell Death following Neonatal Brain Injury

    Directory of Open Access Journals (Sweden)

    Raul Chavez-Valdez

    2012-01-01

    Full Text Available Despite the introduction of therapeutic hypothermia, neonatal hypoxic ischemic (HI brain injury remains a common cause of developmental disability. Development of rational adjuvant therapies to hypothermia requires understanding of the pathways of cell death and survival modulated by HI. The conceptualization of the apoptosis-necrosis “continuum” in neonatal brain injury predicts mechanistic interactions between cell death and hydrid forms of cell death such as programmed or regulated necrosis. Many of the components of the signaling pathway regulating programmed necrosis have been studied previously in models of neonatal HI. In some of these investigations, they participate as part of the apoptotic pathways demonstrating clear overlap of programmed death pathways. Receptor interacting protein (RIP-1 is at the crossroads between types of cellular death and survival and RIP-1 kinase activity triggers formation of the necrosome (in complex with RIP-3 leading to programmed necrosis. Neuroprotection afforded by the blockade of RIP-1 kinase following neonatal HI suggests a role for programmed necrosis in the HI injury to the developing brain. Here, we briefly review the state of the knowledge about the mechanisms behind programmed necrosis in neonatal brain injury recognizing that a significant proportion of these data derive from experiments in cultured cell and some from in vivo adult animal models. There are still more questions than answers, yet the fascinating new perspectives provided by the understanding of programmed necrosis in the developing brain may lay the foundation for new therapies for neonatal HI.

  9. Nuclear calcium controls the apoptotic-like cell death induced by d-erythro-sphinganine in tobacco cells.

    Science.gov (United States)

    Lachaud, Christophe; Da Silva, Daniel; Cotelle, Valérie; Thuleau, Patrice; Xiong, Tou Cheu; Jauneau, Alain; Brière, Christian; Graziana, Annick; Bellec, Yannick; Faure, Jean-Denis; Ranjeva, Raoul; Mazars, Christian

    2010-01-01

    Studies performed in animals have highlighted the major role of sphingolipids in regulating the balance between cell proliferation and cell death. Sphingolipids have also been shown to induce cell death in plants via calcium-based signalling pathways but the contribution of free cytosolic and/or nuclear calcium in the overall process has never been evaluated. Here, we show that increase in tobacco BY-2 cells of the endogenous content of Long Chain Bases (LCBs) caused by external application of d-erythro-sphinganine (DHS) is followed by immediate dose-dependent elevations of cellular free calcium concentration within the first minute in the cytosol and 10min later in the nucleus. Cells challenged with DHS enter a death process through apoptotic-like mechanisms. Lanthanum chloride, a general blocker of calcium entry, suppresses the cellular calcium variations and the PCD induced by DHS. Interestingly, dl-2-amino-5-phosphopentanoic acid (AP5) and [(+)-dizocilpine] (MK801), two inhibitors of animal and plant ionotropic glutamate receptors, suppress DHS-induced cell death symptoms by selectively inhibiting the variations of nuclear calcium concentration. The selective action of these compounds demonstrates the crucial role of nuclear calcium signature in controlling DHS-induced cell death in tobacco cells. 2009 Elsevier Ltd. All rights reserved.

  10. Non-apoptotic cell death associated with perturbations of macropinocytosis

    Directory of Open Access Journals (Sweden)

    William A. Maltese

    2015-02-01

    Full Text Available Although macropinocytosis is widely recognized as a distinct form of fluid-phase endocytosis in antigen-presenting dendritic cells, it also occurs constitutively in many other normal and transformed cell types. Recent studies have established that various genetic or pharmacological manipulations can hyperstimulate macropinocytosis or disrupt normal macropinosome trafficking pathways, leading to accumulation of greatly enlarged cytoplasmic vacuoles. In some cases, this extreme vacuolization is associated with a unique form of non-apoptotic cell death termed ‘methuosis’, from the Greek methuo (to drink to intoxication. It remains unclear whether cell death related to dysfunctional macropinocytosis occurs in normal physiological contexts. However, the finding that some types of cancer cells are particularly vulnerable to this unusual form of cell death has raised the possibility that small molecules capable of altering macropinosome trafficking or function might be useful as therapeutic agents against cancers that are resistant to drugs that work by inducing apoptosis. Herein we review examples of cell death associated with dysfunctional macropinocytosis and summarize what is known about the underlying mechanisms.

  11. Non-apoptotic cell death associated with perturbations of macropinocytosis.

    Science.gov (United States)

    Maltese, William A; Overmeyer, Jean H

    2015-01-01

    Although macropinocytosis is widely recognized as a distinct form of fluid-phase endocytosis in antigen-presenting dendritic cells, it also occurs constitutively in many other normal and transformed cell types. Recent studies have established that various genetic or pharmacological manipulations can hyperstimulate macropinocytosis or disrupt normal macropinosome trafficking pathways, leading to accumulation of greatly enlarged cytoplasmic vacuoles. In some cases, this extreme vacuolization is associated with a unique form of non-apoptotic cell death termed "methuosis," from the Greek methuo (to drink to intoxication). It remains unclear whether cell death related to dysfunctional macropinocytosis occurs in normal physiological contexts. However, the finding that some types of cancer cells are particularly vulnerable to this unusual form of cell death has raised the possibility that small molecules capable of altering macropinosome trafficking or function might be useful as therapeutic agents against cancers that are resistant to drugs that work by inducing apoptosis. Herein we review examples of cell death associated with dysfunctional macropinocytosis and summarize what is known about the underlying mechanisms.

  12. Regulators of Tfh cell differentiation

    Directory of Open Access Journals (Sweden)

    Gajendra Motiram Jogdand

    2016-11-01

    Full Text Available The follicular helper T (Tfh cells help is critical for activation of B cells, antibody class switching and germinal center formation. The Tfh cells are characterized by the expression of CXCR5, ICOS, PD-1, Bcl-6, and IL-21. They are involved in clearing infections and are adversely linked with autoimmune diseases and also have a role in viral replication as well as clearance. Tfh cells are generated from naïve CD4 T cells with sequential steps involving cytokine signaling (IL-21, IL-6, IL-12, activin A, migration and positioning in the germinal center by CXCR5, surface receptors (ICOS/ICOSL, SAP/SLAM as well as transcription factor (Bcl-6, c-Maf, STAT3 signaling and repressor miR155. On the other hand Tfh generation is negatively regulated at specific steps of Tfh generation by specific cytokine (IL-2, IL-7, surface receptor (PD-1, CTLA-4, transcription factors Blimp-1, STAT5, T-bet, KLF-2 signaling and repressor miR 146a. Interestingly, miR 17-92 and FOXO1 acts as a positive as well as a negative regulator of Tfh differentiation depending on the time of expression and disease specificity. Tfh cells are also generated from the conversion of other effector T cells as exemplified by Th1 cells converting into Tfh during viral infection. The mechanistic details of effector T cells conversion into Tfh are yet to be clear. To manipulate Tfh cells for therapeutic implication and or for effective vaccination strategies, it is important to know positive and negative regulators of Tfh generation. Hence, in this review we have highlighted and interlinked molecular signaling from cytokines, surface receptors, transcription factors, ubiquitin Ligase and miRNA as positive and negative regulators for Tfh differentiation.

  13. Staphylococcus aureus induces eosinophil cell death mediated by α-hemolysin.

    Directory of Open Access Journals (Sweden)

    Lynne R Prince

    Full Text Available Staphylococcus aureus, a major human pathogen, exacerbates allergic disorders, including atopic dermatitis, nasal polyps and asthma, which are characterized by tissue eosinophilia. Eosinophils, via their destructive granule contents, can cause significant tissue damage, resulting in inflammation and further recruitment of inflammatory cells. We hypothesised that the relationship between S. aureus and eosinophils may contribute to disease pathology. We found that supernatants from S. aureus (SH1000 strain cultures cause rapid and profound eosinophil necrosis, resulting in dramatic cell loss within 2 hours. This is in marked contrast to neutrophil granulocytes where no significant cell death was observed (at equivalent dilutions. Supernatants prepared from a strain deficient in the accessory gene regulator (agr that produces reduced levels of many important virulence factors, including the abundantly produced α-hemolysin (Hla, failed to induce eosinophil death. The role of Hla in mediating eosinophil death was investigated using both an Hla deficient SH1000-modified strain, which did not induce eosinophil death, and purified Hla, which induced concentration-dependent eosinophil death via both apoptosis and necrosis. We conclude that S. aureus Hla induces aberrant eosinophil cell death in vitro and that this may increase tissue injury in allergic disease.

  14. Staphylococcus aureus induces eosinophil cell death mediated by α-hemolysin.

    Science.gov (United States)

    Prince, Lynne R; Graham, Kirstie J; Connolly, John; Anwar, Sadia; Ridley, Robert; Sabroe, Ian; Foster, Simon J; Whyte, Moira K B

    2012-01-01

    Staphylococcus aureus, a major human pathogen, exacerbates allergic disorders, including atopic dermatitis, nasal polyps and asthma, which are characterized by tissue eosinophilia. Eosinophils, via their destructive granule contents, can cause significant tissue damage, resulting in inflammation and further recruitment of inflammatory cells. We hypothesised that the relationship between S. aureus and eosinophils may contribute to disease pathology. We found that supernatants from S. aureus (SH1000 strain) cultures cause rapid and profound eosinophil necrosis, resulting in dramatic cell loss within 2 hours. This is in marked contrast to neutrophil granulocytes where no significant cell death was observed (at equivalent dilutions). Supernatants prepared from a strain deficient in the accessory gene regulator (agr) that produces reduced levels of many important virulence factors, including the abundantly produced α-hemolysin (Hla), failed to induce eosinophil death. The role of Hla in mediating eosinophil death was investigated using both an Hla deficient SH1000-modified strain, which did not induce eosinophil death, and purified Hla, which induced concentration-dependent eosinophil death via both apoptosis and necrosis. We conclude that S. aureus Hla induces aberrant eosinophil cell death in vitro and that this may increase tissue injury in allergic disease.

  15. Activation-Induced Cell Death of Dendritic Cells Is Dependent on Sphingosine Kinase 1.

    Science.gov (United States)

    Schwiebs, Anja; Friesen, Olga; Katzy, Elisabeth; Ferreirós, Nerea; Pfeilschifter, Josef M; Radeke, Heinfried H

    2016-01-01

    Sphingosine 1-phosphate (S1P) is an immune modulatory lipid mediator and has been implicated in numerous pathophysiological processes. S1P is produced by sphingosine kinase 1 (Sphk1) and Sphk2. Dendritic cells (DCs) are central for the direction of immune responses and crucially involved in autoimmunity and cancerogenesis. In this study we examined the function and survival of bone marrow-derived DCs under long-term inflammatory stimulation. We observed that differentiated cells undergo activation-induced cell death (AICD) upon LPS stimulation with an increased metabolic activity shortly after stimulation, followed by a rapid activation of caspase 3 and subsequent augmented apoptosis. Importantly, we highlight a profound role of Sphk1 in secretion of inflammatory cytokines and survival of dendritic cells that might be mediated by a change in sphingolipid levels as well as by a change in STAT3 expression. Cell growth during differentiation of Sphk1-deficient cells treated with the functional S1P receptor antagonist FTYP was reduced. Importantly, in dendritic cells we did not observe a compensatory regulation of Sphk2 mRNA in Sphk1-deficient cells. Instead, we discovered a massive increase in Sphk1 mRNA concentration upon long-term stimulation with LPS in wild type cells that might function as an attempt to rescue from inflammation-caused cell death. Taken together, in this investigation we describe details of a crucial involvement of sphingolipids and Sphk1 in AICD during long-term immunogenic activity of DCs that might play an important role in autoimmunity and might explain the differences in immune response observed in in vivo studies of Sphk1 modulation.

  16. METACASPASE9 modulates autophagy to confine cell death to the target cells during Arabidopsis vascular xylem differentiation

    Directory of Open Access Journals (Sweden)

    Sacha Escamez

    2016-02-01

    Full Text Available We uncovered that the level of autophagy in plant cells undergoing programmed cell death determines the fate of the surrounding cells. Our approach consisted of using Arabidopsis thaliana cell cultures capable of differentiating into two different cell types: vascular tracheary elements (TEs that undergo programmed cell death (PCD and protoplast autolysis, and parenchymatic non-TEs that remain alive. The TE cell type displayed higher levels of autophagy when expression of the TE-specific METACASPASE9 (MC9 was reduced using RNAi (MC9-RNAi. Misregulation of autophagy in the MC9-RNAi TEs coincided with ectopic death of the non-TEs, implying the existence of an autophagy-dependent intercellular signalling from within the TEs towards the non-TEs. Viability of the non-TEs was restored when AUTOPHAGY2 (ATG2 was downregulated specifically in MC9-RNAi TEs, demonstrating the importance of autophagy in the spatial confinement of cell death. Our results suggest that other eukaryotic cells undergoing PCD might also need to tightly regulate their level of autophagy to avoid detrimental consequences for the surrounding cells.

  17. Oxidative Stress and Programmed Cell Death in Yeast

    Science.gov (United States)

    Farrugia, Gianluca; Balzan, Rena

    2012-01-01

    Yeasts, such as Saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies. This review will discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ROS), their molecular targets, and the metabolic responses elicited by cellular ROS accumulation. Responses of yeast to accumulated ROS include upregulation of antioxidants mediated by complex transcriptional changes, activation of pro-survival pathways such as mitophagy, and programmed cell death (PCD) which, apart from apoptosis, includes pathways such as autophagy and necrosis, a form of cell death long considered accidental and uncoordinated. The role of ROS in yeast aging will also be discussed. PMID:22737670

  18. Induction of Cancer Cell Death by Isoflavone: The Role of Multiple Signaling Pathways

    Science.gov (United States)

    Li, Yiwei; Kong, Dejuan; Bao, Bin; Ahmad, Aamir; Sarkar, Fazlul H.

    2011-01-01

    Soy isoflavones have been documented as dietary nutrients broadly classified as “natural agents” which plays important roles in reducing the incidence of hormone-related cancers in Asian countries, and have shown inhibitory effects on cancer development and progression in vitro and in vivo, suggesting the cancer preventive or therapeutic activity of soy isoflavones against cancers. Emerging experimental evidence shows that isoflavones could induce cancer cell death by regulating multiple cellular signaling pathways including Akt, NF-κB, MAPK, Wnt, androgen receptor (AR), p53 and Notch signaling, all of which have been found to be deregulated in cancer cells. Therefore, homeostatic regulation of these important cellular signaling pathways by isoflavones could be useful for the activation of cell death signaling, which could result in the induction of apoptosis of both pre-cancerous and/or cancerous cells without affecting normal cells. In this article, we have attempted to summarize the current state-of-our-knowledge regarding the induction of cancer cell death pathways by isoflavones, which is believed to be mediated through the regulation of multiple cellular signaling pathways. The knowledge gained from this article will provide a comprehensive view on the molecular mechanism(s) by which soy isoflavones may exert their effects on the prevention of tumor progression and/or treatment of human malignancies, which would also aid in stimulating further in-depth mechanistic research and foster the initiation of novel clinical trials. PMID:22200028

  19. Sensory hair cell death and regeneration in fishes

    Directory of Open Access Journals (Sweden)

    Jerry D. Monroe

    2015-04-01

    Full Text Available Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation versus direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.

  20. Pulsating electromagnetic field stimulation prevents cell death of puromycin treated U937 cell line.

    Science.gov (United States)

    Kaszuba-Zwoinska, J; Wojcik, K; Bereta, M; Ziomber, A; Pierzchalski, P; Rokita, E; Marcinkiewicz, J; Zaraska, W; Thor, P

    2010-04-01

    Aim of study was to verify whether pulsating electromagnetic field (PEMF) can affect cancer cells proliferation and death. U937 human lymphoid cell line at densities starting from 1 x 10(6) cells/ml to 0.0625 x 10(6) cells/ml, were exposed to a pulsating magnetic field 50 Hz, 45+/-5 mT three times for 3 h per each stimulation with 24 h intervals. Proliferation has been studied by counting number of cells stimulated and non-stimulated by PEMF during four days of cultivation. Viability of cells was analyzed by APC labeled Annexin V and 7-AAD (7-amino-actinomycin D) dye binding and flow cytometry. Growing densities of cells increase cell death in cultures of U937 cells. PEMF exposition decreased amount of cells only in higher densities. Measurement of Annexin V binding and 7-AAD dye incorporation has shown that density-induced cell death corresponds with decrease of proliferation activity. PEMF potentiated density-induced death both apoptosis and necrosis. The strongest influence of PEMF has been found for 1 x 10(6)cells/ml and 0.5 x 10(6) cells/ml density. To eliminate density effect on cell death, for further studies density 0.25 x 10(6) cells/ml was chosen. Puromycin, a telomerase inhibitor, was used as a cell death inducer at concentration 100 microg/ml. Combined interaction of three doses of puromycin and three fold PEMF interaction resulted in a reduced of apoptosis by 24,7% and necrosis by 13%. PEMF protects U937 cells against puromycin- induced cell death. PEMF effects on the human lymphoid cell line depends upon cell density. Increased density induced cells death and on the other hand prevented cells death induced by puromycin.

  1. Molecular characterization of propolis-induced cell death in Saccharomyces cerevisiae.

    Science.gov (United States)

    de Castro, Patrícia Alves; Savoldi, Marcela; Bonatto, Diego; Barros, Mário Henrique; Goldman, Maria Helena S; Berretta, Andresa A; Goldman, Gustavo Henrique

    2011-03-01

    Propolis, a natural product of plant resins, is used by the bees to seal holes in their honeycombs and protect the hive entrance. However, propolis has also been used in folk medicine for centuries. Here, we apply the power of Saccharomyces cerevisiae as a model organism for studies of genetics, cell biology, and genomics to determine how propolis affects fungi at the cellular level. Propolis is able to induce an apoptosis cell death response. However, increased exposure to propolis provides a corresponding increase in the necrosis response. We showed that cytochrome c but not endonuclease G (Nuc1p) is involved in propolis-mediated cell death in S. cerevisiae. We also observed that the metacaspase YCA1 gene is important for propolis-mediated cell death. To elucidate the gene functions that may be required for propolis sensitivity in eukaryotes, the full collection of about 4,800 haploid S. cerevisiae deletion strains was screened for propolis sensitivity. We were able to identify 138 deletion strains that have different degrees of propolis sensitivity compared to the corresponding wild-type strains. Systems biology revealed enrichment for genes involved in the mitochondrial electron transport chain, vacuolar acidification, negative regulation of transcription from RNA polymerase II promoter, regulation of macroautophagy associated with protein targeting to vacuoles, and cellular response to starvation. Validation studies indicated that propolis sensitivity is dependent on the mitochondrial function and that vacuolar acidification and autophagy are important for yeast cell death caused by propolis.

  2. Molecular Characterization of Propolis-Induced Cell Death in Saccharomyces cerevisiae▿†

    Science.gov (United States)

    de Castro, Patrícia Alves; Savoldi, Marcela; Bonatto, Diego; Barros, Mário Henrique; Goldman, Maria Helena S.; Berretta, Andresa A.; Goldman, Gustavo Henrique

    2011-01-01

    Propolis, a natural product of plant resins, is used by the bees to seal holes in their honeycombs and protect the hive entrance. However, propolis has also been used in folk medicine for centuries. Here, we apply the power of Saccharomyces cerevisiae as a model organism for studies of genetics, cell biology, and genomics to determine how propolis affects fungi at the cellular level. Propolis is able to induce an apoptosis cell death response. However, increased exposure to propolis provides a corresponding increase in the necrosis response. We showed that cytochrome c but not endonuclease G (Nuc1p) is involved in propolis-mediated cell death in S. cerevisiae. We also observed that the metacaspase YCA1 gene is important for propolis-mediated cell death. To elucidate the gene functions that may be required for propolis sensitivity in eukaryotes, the full collection of about 4,800 haploid S. cerevisiae deletion strains was screened for propolis sensitivity. We were able to identify 138 deletion strains that have different degrees of propolis sensitivity compared to the corresponding wild-type strains. Systems biology revealed enrichment for genes involved in the mitochondrial electron transport chain, vacuolar acidification, negative regulation of transcription from RNA polymerase II promoter, regulation of macroautophagy associated with protein targeting to vacuoles, and cellular response to starvation. Validation studies indicated that propolis sensitivity is dependent on the mitochondrial function and that vacuolar acidification and autophagy are important for yeast cell death caused by propolis. PMID:21193549

  3. Identification of a cell death pathway in Candida albicans during the response to pheromone.

    Science.gov (United States)

    Alby, Kevin; Schaefer, Dana; Sherwood, Racquel Kim; Jones, Stephen K; Bennett, Richard J

    2010-11-01

    Mating in hemiascomycete yeasts involves the secretion of pheromones that induce sexual differentiation in cells of the opposite mating type. Studies in Saccharomyces cerevisiae have revealed that a subpopulation of cells experiences cell death during exposure to pheromone. In this work, we tested whether the phenomenon of pheromone-induced death (PID) also occurs in the opportunistic pathogen Candida albicans. Mating in C. albicans is uniquely regulated by white-opaque phenotypic switching; both cell types respond to pheromone, but only opaque cells undergo the morphological transition and cell conjugation. We show that approximately 20% of opaque cells, but not white cells, of laboratory strain SC5314 experience pheromone-induced death. Furthermore, analysis of mutant strains revealed that PID was significantly reduced in strains lacking Fig1 or Fus1 transmembrane proteins that are induced during the mating process and, we now show, are necessary for efficient mating in C. albicans. The level of PID was also Ca(2+) dependent, as chelation of Ca(2+) ions increased cell death to almost 50% of the population. However, in contrast to S. cerevisiae PID, pheromone-induced killing of C. albicans cells was largely independent of signaling via the Ca(2+)-dependent protein phosphatase calcineurin, even when combined with the loss of Cmk1 and Cmk2 proteins. Finally, we demonstrate that levels of PID vary widely between clinical isolates of C. albicans, with some strains experiencing close to 70% cell death. We discuss these findings in light of the role of prodeath and prosurvival pathways operating in yeast cells undergoing the morphological response to pheromone.

  4. Herceptin conjugates linked by EDC boost direct tumor cell death via programmed tumor cell necrosis.

    Directory of Open Access Journals (Sweden)

    Jiemiao Hu

    Full Text Available Tumor-targeted antibody therapy is one of the safest biological therapeutics for cancer patients, but it is often ineffective at inducing direct tumor cell death and is ineffective against resistant tumor cells. Currently, the antitumor efficacy of antibody therapy is primarily achieved by inducing indirect tumor cell death, such as antibody-dependent cell cytotoxicity. Our study reveals that Herceptin conjugates, if generated via the crosslinker EDC (1-ethyl-3-(3-dimethylaminopropyl carbodiimide hydrochloride, are capable of engendering human epidermal growth factor receptor 2 (Her2 positive tumor cells death. Using a high-performance liquid chromatography (HPLC system, three peaks with estimated molecular weights of antibody monomer, dimer, and trimer were isolated. Both Herceptin trimer and dimer separated by HPLC induced significant levels of necrotic tumor cell death, although the trimer was more effective than the dimer. Notably, the Herceptin trimer also induced Herceptin-resistant tumor cell death. Surprisingly different from the known cell death mechanism that often results from antibody treatment, the Herceptin trimer elicited effective and direct tumor cell death via a novel mechanism: programmed cell necrosis. In Her2-positive cells, inhibition of necrosis pathways significantly reversed Herceptin trimer-induced cell death. In summary, the Herceptin trimer reported herein harbors great potential for overcoming tumor cell resistance to Herceptin treatment.

  5. Herceptin Conjugates Linked by EDC Boost Direct Tumor Cell Death via Programmed Tumor Cell Necrosis

    Science.gov (United States)

    Hughes, Dennis; Esteva, Francisco J.; Liu, Bolin; Chandra, Joya; Li, Shulin

    2011-01-01

    Tumor-targeted antibody therapy is one of the safest biological therapeutics for cancer patients, but it is often ineffective at inducing direct tumor cell death and is ineffective against resistant tumor cells. Currently, the antitumor efficacy of antibody therapy is primarily achieved by inducing indirect tumor cell death, such as antibody-dependent cell cytotoxicity. Our study reveals that Herceptin conjugates, if generated via the crosslinker EDC (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride), are capable of engendering human epidermal growth factor receptor 2 (Her2) positive tumor cells death. Using a high-performance liquid chromatography (HPLC) system, three peaks with estimated molecular weights of antibody monomer, dimer, and trimer were isolated. Both Herceptin trimer and dimer separated by HPLC induced significant levels of necrotic tumor cell death, although the trimer was more effective than the dimer. Notably, the Herceptin trimer also induced Herceptin-resistant tumor cell death. Surprisingly different from the known cell death mechanism that often results from antibody treatment, the Herceptin trimer elicited effective and direct tumor cell death via a novel mechanism: programmed cell necrosis. In Her2-positive cells, inhibition of necrosis pathways significantly reversed Herceptin trimer-induced cell death. In summary, the Herceptin trimer reported herein harbors great potential for overcoming tumor cell resistance to Herceptin treatment. PMID:21853100

  6. Two distinct Ras genes from Puccinia striiformis exhibit differential roles in rust pathogenicity and cell death.

    Science.gov (United States)

    Cheng, Yulin; Wang, Wumei; Yao, Juanni; Huang, Lili; Voegele, Ralf T; Wang, Xiaojie; Kang, Zhensheng

    2016-11-01

    Ras genes have been shown to regulate a variety of cellular processes in higher eukaryotes. However, much less is known about their function(s) in fungi, especially plant pathogenic fungi. Here, we report the identification and functional analysis of Ras genes from Puccinia striiformis f. sp. tritici (Pst), an important fungal pathogen in wheat production worldwide. Pst contains two Ras genes, PsRas1 and PsRas2, which share 48.6% similarity at the protein level and fall into two different phylogenetic clades. Both PsRas1 and PsRas2 have conserved protein sequences among different Pst isolates, but exhibit different transcript profiles during Pst infection. Silencing of PsRas1 or PsRas2 indicates that PsRas2 but not PsRas1 contributes significantly to rust pathogenicity. However, overexpression of PsRas1, but not PsRas2, promotes cell death in yeast and plants. Further studies show that all conserved domains of Ras GTPases in PsRas1 are needed to induce this cell death. In plants, PsRas1-triggered cell death shows similar characteristics as plant hypersensitive response. Our findings suggest that PsRas1 and PsRas2 take over different functions in rust pathogenicity and cell death, thus facilitating the understanding of cell death, pathogenic mechanisms of plant pathogenic fungi and the search for novel pathogen control strategies. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Light influences how the fungal toxin deoxynivalenol affects plant cell death and defense responses

    National Research Council Canada - National Science Library

    Ansari, Khairul I; Doyle, Siamsa M; Kacprzyk, Joanna; Khan, Mojibur R; Walter, Stephanie; Brennan, Josephine M; Arunachalam, Chanemouga Soundharam; McCabe, Paul F; Doohan, Fiona M

    2014-01-01

    ... (Arabidopsis thaliana) cell cultures. We show that 10 μg mL(-1) DON does not cause cell death in Arabidopsis cell cultures, and its ability to retard heat-induced cell death is light dependent...

  8. Control of cell death pathways by HTLV-1 proteins.

    Science.gov (United States)

    Saggioro, Daniela; Silic-Benussi, Micol; Biasiotto, Roberta; D'Agostino, Donna M; Ciminale, Vincenzo

    2009-01-01

    Individuals infected with HTLV-1 harbor the virus mainly in CD4+ memory T-cells as a lifelong infection that remains subclinical in the majority of cases. However, about 3-5% of HTLV-1-infected individuals develop an aggressive T-cell neoplasia (ATLL) or a neurodegenerative disease (TSP/HAM) after a latency period ranging from years to decades. This review summarizes the current knowledge of the effects of the HTLV-1 proteins Tax, p13 and p12 on cell death and survival pathways. Tax, the major oncogenic determinant of HTLV-1, enhances cell survival through its effects on the NF-kappaB, CREB and AKT pathways and on the tumor suppressors p53 and Rb. p13 is targeted to the inner mitochondrial membrane and sensitizes cells to the Fas/ceramide apoptotic pathway and reactive oxygen species-mediated cell death. p12 enhances release of calcium from the endoplasmic reticulum and therefore may influence calcium-dependent apoptotic signals, including opening of the mitochondrial permeability transition pore. The long-term fate of HTLV-1-infected cells (apoptosis, survival, transformation) may therefore depend on the balance of the effects of Tax, p13 and p12 on cell death pathways.

  9. Hydrogen peroxide produced by oral Streptococci induces macrophage cell death.

    Directory of Open Access Journals (Sweden)

    Nobuo Okahashi

    Full Text Available Hydrogen peroxide (H2O2 produced by members of the mitis group of oral streptococci plays important roles in microbial communities such as oral biofilms. Although the cytotoxicity of H2O2 has been widely recognized, the effects of H2O2 produced by oral streptococci on host defense systems remain unknown. In the present study, we investigated the effect of H2O2 produced by Streptococcus oralis on human macrophage cell death. Infection by S. oralis was found to stimulate cell death of a THP-1 human macrophage cell line at multiplicities of infection greater than 100. Catalase, an enzyme that catalyzes the decomposition of H2O2, inhibited the cytotoxic effect of S. oralis. S. oralis deletion mutants lacking the spxB gene, which encodes pyruvate oxidase, and are therefore deficient in H2O2 production, showed reduced cytotoxicity toward THP-1 macrophages. Furthermore, H2O2 alone was capable of inducing cell death. The cytotoxic effect seemed to be independent of inflammatory responses, because H2O2 was not a potent stimulator of tumor necrosis factor-α production in macrophages. These results indicate that streptococcal H2O2 plays a role as a cytotoxin, and is implicated in the cell death of infected human macrophages.

  10. CD40 stimulation sensitizes CLL cells to rituximab-induced cell death

    NARCIS (Netherlands)

    Jak, M.; van Bochove, G. G. W.; van Lier, R. A. W.; Eldering, E.; van Oers, M. H. J.

    2011-01-01

    In vitro CD40-stimulated chronic lymphocytic leukemia (CLL) cells are resistant to cytotoxic drugs. In sharp contrast, we here show that CD40 stimulation sensitizes CLL cells to rituximab-mediated cell death. This increased sensitivity is specific for anti-CD20 treatment. Rituximab-mediated death in

  11. Cross-talk of nitric oxide and reactive oxygen species in plant programed cell death

    Directory of Open Access Journals (Sweden)

    Yiqin eWang

    2013-08-01

    Full Text Available In plants, programed cell death (PCD is an important mechanism to regulate multiple aspects of growth and development, as well as to remove damaged or infected cells during responses to environmental stresses and pathogen attacks. Under biotic and abiotic stresses, plant cells exhibit a rapid synthesis of nitric oxide (NO and a parallel accumulation of reactive oxygen species (ROS. Frequently, these responses trigger a PCD process leading to an intrinsic execution of plant cells. The accumulating evidence suggests that both NO and ROS play key roles in PCD. These redox active small molecules can trigger cell death either independently or synergistically. Here we summarize the recent progress on the cross-talk of NO and ROS signals in the hypersensitive response (HR, leaf senescence and other kinds of plant PCD caused by diverse cues.

  12. Cross-talk of nitric oxide and reactive oxygen species in plant programed cell death.

    Science.gov (United States)

    Wang, Yiqin; Loake, Gary J; Chu, Chengcai

    2013-01-01

    In plants, programed cell death (PCD) is an important mechanism to regulate multiple aspects of growth and development, as well as to remove damaged or infected cells during responses to environmental stresses and pathogen attacks. Under biotic and abiotic stresses, plant cells exhibit a rapid synthesis of nitric oxide (NO) and a parallel accumulation of reactive oxygen species (ROS). Frequently, these responses trigger a PCD process leading to an intrinsic execution of plant cells. The accumulating evidence suggests that both NO and ROS play key roles in PCD. These redox active small molecules can trigger cell death either independently or synergistically. Here we summarize the recent progress on the cross-talk of NO and ROS signals in the hypersensitive response, leaf senescence, and other kinds of plant PCD caused by diverse cues.

  13. Ammonium is toxic for aging yeast cells, inducing death and shortening of the chronological lifespan.

    Directory of Open Access Journals (Sweden)

    Júlia Santos

    Full Text Available Here we show that in aging Saccharomyces cerevisiae (budding yeast cells, NH(4 (+ induces cell death associated with shortening of chronological life span. This effect is positively correlated with the concentration of NH(4 (+ added to the culture medium and is particularly evident when cells are starved for auxotrophy-complementing amino acids. NH(4 (+-induced cell death is accompanied by an initial small increase of apoptotic cells followed by extensive necrosis. Autophagy is inhibited by NH(4 (+, but this does not cause a decrease in cell viability. We propose that the toxic effects of NH(4 (+ are mediated by activation of PKA and TOR and inhibition of Sch9p. Our data show that NH(4 (+ induces cell death in aging cultures through the regulation of evolutionary conserved pathways. They may also provide new insights into longevity regulation in multicellular organisms and increase our understanding of human disorders such as hyperammonemia as well as effects of amino acid deprivation employed as a therapeutic strategy.

  14. Nuclear DAMP complex-mediated RAGE-dependent macrophage cell death

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ruochan [Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Department of Infectious Diseases and State Key Lab of Viral Hepatitis, Xiangya Hospital, Central South University, Changsha, Hunan 410008 (China); Fu, Sha; Fan, Xue-Gong [Department of Infectious Diseases and State Key Lab of Viral Hepatitis, Xiangya Hospital, Central South University, Changsha, Hunan 410008 (China); Lotze, Michael T.; Zeh, Herbert J. [Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Tang, Daolin, E-mail: tangd2@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Kang, Rui, E-mail: kangr@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213 (United States)

    2015-03-13

    High mobility group box 1 (HMGB1), histone, and DNA are essential nuclear components involved in the regulation of chromosome structure and function. In addition to their nuclear function, these molecules act as damage-associated molecular patterns (DAMPs) alone or together when released extracellularly. The synergistic effect of these nuclear DNA-HMGB1-histone complexes as DAMP complexes (nDCs) on immune cells remains largely unexplored. Here, we demonstrate that nDCs limit survival of macrophages (e.g., RAW264.7 and peritoneal macrophages) but not cancer cells (e.g., HCT116, HepG2 and Hepa1-6). nDCs promote production of inflammatory tumor necrosis factor α (TNFα) release, triggering reactive oxygen species-dependent apoptosis and necrosis. Moreover, the receptor for advanced glycation end products (RAGE), but not toll-like receptor (TLR)-4 and TLR-2, was required for Akt-dependent TNFα release and subsequent cell death following treatment with nDCs. Genetic depletion of RAGE by RNAi, antioxidant N-Acetyl-L-cysteine, and TNFα neutralizing antibody significantly attenuated nDC-induced cell death. These findings provide evidence supporting novel signaling mechanisms linking nDCs and inflammation in macrophage cell death. - Highlights: • Nuclear DAMP complexes (nDCs) selectively induce cell death in macrophages, but not cancer cells. • TNFα-mediated oxidative stress is required for nDC-induced death. • RAGE-mediated Akt activation is required for nDC-induced TNFα release. • Blocking RAGE and TNFα inhibits nDC-induced macrophage cell death.

  15. Retinal Cell Death Caused by Sodium Iodate Involves Multiple Caspase-Dependent and Caspase-Independent Cell-Death Pathways

    Directory of Open Access Journals (Sweden)

    Jasmin Balmer

    2015-07-01

    Full Text Available Herein, we have investigated retinal cell-death pathways in response to the retina toxin sodium iodate (NaIO3 both in vivo and in vitro. C57/BL6 mice were treated with a single intravenous injection of NaIO3 (35 mg/kg. Morphological changes in the retina post NaIO3 injection in comparison to untreated controls were assessed using electron microscopy. Cell death was determined by TdT-mediated dUTP-biotin nick end labeling (TUNEL staining. The activation of caspases and calpain was measured using immunohistochemistry. Additionally, cytotoxicity and apoptosis in retinal pigment epithelial (RPE cells, primary retinal cells, and the cone photoreceptor (PRC cell line 661W were assessed in vitro after NaIO3 treatment using the ApoToxGlo™ assay. The 7-AAD/Annexin-V staining was performed and necrostatin (Nec-1 was administered to the NaIO3-treated cells to confirm the results. In vivo, degenerating RPE cells displayed a rounded shape and retracted microvilli, whereas PRCs featured apoptotic nuclei. Caspase and calpain activity was significantly upregulated in retinal sections and protein samples from NaIO3-treated animals. In vitro, NaIO3 induced necrosis in RPE cells and apoptosis in PRCs. Furthermore, Nec-1 significantly decreased NaIO3-induced RPE cell death, but had no rescue effect on treated PRCs. In summary, several different cell-death pathways are activated in retinal cells as a result of NaIO3.

  16. Induction of immunogenic cell death of tumors by newly synthesized heterocyclic quinone derivative.

    Directory of Open Access Journals (Sweden)

    Keum-Joo Son

    Full Text Available Many cancer types are serious diseases causing mortality, and new therapeutics with improved efficacy and safety are required. Immuno-(cell-therapy is considered as one of the promising therapeutic strategies for curing intractable cancer. In this study, we tested R2016, a newly developed heterocyclic quinone derivative, for induction of immunogenic tumor cell death and as a possible novel immunochemotherapeutic. We studied the anti-cancer effects of R2016 against LLC, a lung cancer cell line and B16F10, a melanoma cell line. LLC (non-immunogenic and B16F10 (immunogenic cells were killed by R2016 in dose-dependent manner. R2016 reduced the viability of both LLC and B16F10 tumor cells by inducing apoptosis and necrosis, while it demonstrated no cytotoxicity against normal splenocytes. Expression of immunogenic death markers on the cell surface of R2016 treated tumor cells including calreticulin (CRT and heat shock proteins (HSPs was increased along with the induction of their genes. Increased CRT expression correlated with dendritic cell (DC uptake of dying tumor cells: the proportion of CRT+CD11c+cells was increased in the R2016-treated group. The gene transcription of Calr3, Hspb1, and Tnfaip6, which are related to immunogenicity induction of dead cells, was up-regulated in the R2016 treated tumor cells. On the other hand, ANGPT1, FGF7, and URGCP gene levels were down-regulated by R2016 treatment. This data suggests that R2016 induced immunogenic tumor cell death, and suggests R2016 as an effective anti-tumor immunochemotherapeutic modality.

  17. Induction of immunogenic cell death of tumors by newly synthesized heterocyclic quinone derivative.

    Science.gov (United States)

    Son, Keum-Joo; Choi, Ki Ryung; Ryu, Chung-Kyu; Lee, Seog Jae; Kim, Ho Jeong; Lee, Hyunah

    2017-01-01

    Many cancer types are serious diseases causing mortality, and new therapeutics with improved efficacy and safety are required. Immuno-(cell)-therapy is considered as one of the promising therapeutic strategies for curing intractable cancer. In this study, we tested R2016, a newly developed heterocyclic quinone derivative, for induction of immunogenic tumor cell death and as a possible novel immunochemotherapeutic. We studied the anti-cancer effects of R2016 against LLC, a lung cancer cell line and B16F10, a melanoma cell line. LLC (non-immunogenic) and B16F10 (immunogenic) cells were killed by R2016 in dose-dependent manner. R2016 reduced the viability of both LLC and B16F10 tumor cells by inducing apoptosis and necrosis, while it demonstrated no cytotoxicity against normal splenocytes. Expression of immunogenic death markers on the cell surface of R2016 treated tumor cells including calreticulin (CRT) and heat shock proteins (HSPs) was increased along with the induction of their genes. Increased CRT expression correlated with dendritic cell (DC) uptake of dying tumor cells: the proportion of CRT+CD11c+cells was increased in the R2016-treated group. The gene transcription of Calr3, Hspb1, and Tnfaip6, which are related to immunogenicity induction of dead cells, was up-regulated in the R2016 treated tumor cells. On the other hand, ANGPT1, FGF7, and URGCP gene levels were down-regulated by R2016 treatment. This data suggests that R2016 induced immunogenic tumor cell death, and suggests R2016 as an effective anti-tumor immunochemotherapeutic modality.

  18. N-acetylcysteine effectively mitigates cadmium-induced oxidative damage and cell death in Leydig cells in vitro.

    Science.gov (United States)

    Khanna, Smita; Mitra, Sumonto; Lakhera, Pramesh C; Khandelwal, Shashi

    2016-01-01

    Cadmium (Cd) is known to cause severe damage to various organs including lung, liver, kidney, brain and reproductive system. Several studies have reported the induction of oxidative stress pathways following Cd exposure. Since oxidative stress is also deemed responsible for inducing male infertility, a growing worldwide concern, we tried to understand whether the antioxidant N-acetylcysteine (NAC) can be a potential therapeutic agent to counter Cd toxicity using primary Leydig cells. This study highlights the initial cellular alterations which culminate in cell death induction. Primary Leydig cells were isolated from 28-day-old male Wistar rats, exposed to various concentrations of Cd in vitro and biochemical and cell death parameters were evaluated to understand the effect of Cd. NAC pre-treatment was done to understand its protective efficacy. Following Cd exposure to Leydig cells in vitro, we found simultaneous intracellular calcium (Ca(2+)) increase and reduction in mitochondrial membrane polarization at 30 min, followed by significant induction of reactive oxygen species and MAPK-extracellular-regulated kinases with concurrent glutathione depletion at 1 h, and significant cell death (both necrotic and apoptotic) at 6 and 18 h, respectively. Pre-treatment with NAC abrogated all these toxic manifestations and showed significantly reduced cell death. NAC also rescued the expression of 3-βHSD, a major steroidogenic protein. Taken together, these data illustrated that NAC can be used as a potential protective agent against Cd-induced testicular toxicity, especially with regards to oxidative stress-induced Leydig cell toxicity.

  19. Heat shock genes–integrating cell survival and death

    Indian Academy of Sciences (India)

    2007-03-22

    Mar 22, 2007 ... Heat shock induced gene expression and other cellular responses help limit the damage caused by stress and thus facilitate cellular recovery. Cellular damage also triggers apoptotic cell death through several pathways. This paper briefly reviews interactions of the major heat shock proteins with ...

  20. Mitochondrial and Cell Death Mechanisms in Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Lee J. Martin

    2010-03-01

    Full Text Available Alzheimer’s disease (AD, Parkinson’s disease (PD and amyotrophic lateral sclerosis (ALS are the most common human adult-onset neurodegenerative diseases. They are characterized by prominent age-related neurodegeneration in selectively vulnerable neural systems. Some forms of AD, PD, and ALS are inherited, and genes causing these diseases have been identified. Nevertheless, the mechanisms of the neuronal cell death are unresolved. Morphological, biochemical, genetic, as well as cell and animal model studies reveal that mitochondria could have roles in this neurodegeneration. The functions and properties of mitochondria might render subsets of selectively vulnerable neurons intrinsically susceptible to cellular aging and stress and overlying genetic variations, triggering neurodegeneration according to a cell death matrix theory. In AD, alterations in enzymes involved in oxidative phosphorylation, oxidative damage, and mitochondrial binding of Aβ and amyloid precursor protein have been reported. In PD, mutations in putative mitochondrial proteins have been identified and mitochondrial DNA mutations have been found in neurons in the substantia nigra. In ALS, changes occur in mitochondrial respiratory chain enzymes and mitochondrial cell death proteins. Transgenic mouse models of human neurodegenerative disease are beginning to reveal possible principles governing the biology of selective neuronal vulnerability that implicate mitochondria and the mitochondrial permeability transition pore. This review summarizes how mitochondrial pathobiology might contribute to neuronal death in AD, PD, and ALS and could serve as a target for drug therapy.

  1. Mitochondria can Power Cells to Life and Death

    Indian Academy of Sciences (India)

    apoptosis. Failed apoptosis may give rise to cancer, whereas excessive cell death may result in Alzheimer's disease, Parkinson's disease, atherosclerosis, ischemic heart disease and many others. (Table 2). A number of agents, including those of viral origin, have been found to inhibit the process of apoptosis (Table 3).

  2. Immunohistochemical Aspects of Cell Death in Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Bălăşescu Elena

    2016-03-01

    Full Text Available Introduction. Diabetes Mellitus causes ultrastructural changes triggered by partially clarified cellular mechanisms. Since cell death is an important mechanism in the appearance and progression of diabetic nephropathy, we studied alteration of several markers of apoptotic pathways signaling in renal tissue of diabetic or prediabetic patients.

  3. What history tells us XXI. Apoptosis and programmed cell death ...

    Indian Academy of Sciences (India)

    2010-04-30

    Apr 30, 2010 ... Home; Journals; Journal of Biosciences; Volume 35; Issue 2. What history tells us XXI. Apoptosis and programmed cell death: when biological categories are blurred. Michel Morange. Series Volume 35 Issue 2 June 2010 pp 177-181 ...

  4. Bortezomib induces autophagic death in proliferating human endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Belloni, Daniela; Veschini, Lorenzo [Myeloma Unit, Department of Oncology, IRCCS H San Raffaele, Milan (Italy); Foglieni, Chiara [Department of Cardiology, IRCCS H San Raffaele, Milan (Italy); Dell' Antonio, Giacomo [Department of Pathology, IRCCS H San Raffaele, Milan (Italy); Caligaris-Cappio, Federico [Myeloma Unit, Department of Oncology, IRCCS H San Raffaele, Milan (Italy); Universita Vita-Salute IRCCS H San Raffaele, Milan (Italy); Ferrarini, Marina [Myeloma Unit, Department of Oncology, IRCCS H San Raffaele, Milan (Italy); Ferrero, Elisabetta, E-mail: elisabetta.ferrero@hsr.it [Myeloma Unit, Department of Oncology, IRCCS H San Raffaele, Milan (Italy)

    2010-04-01

    The proteasome inhibitor Bortezomib has been approved for the treatment of relapsed/refractory multiple myeloma (MM), thanks to its ability to induce MM cell apoptosis. Moreover, Bortezomib has antiangiogenic properties. We report that endothelial cells (EC) exposed to Bortezomib undergo death to an extent that depends strictly on their activation state. Indeed, while quiescent EC are resistant to Bortezomib, the drug results maximally toxic in EC switched toward angiogenesis with FGF, and exerts a moderate effect on subconfluent HUVEC. Moreover, EC activation state deeply influences the death pathway elicited by Bortezomib: after treatment, angiogenesis-triggered EC display typical features of apoptosis. Conversely, death of subconfluent EC is preceded by ROS generation and signs typical of autophagy, including intense cytoplasmic vacuolization with evidence of autophagosomes at electron microscopy, and conversion of the cytosolic MAP LC3 I form toward the autophagosome-associated LC3 II form. Treatment with the specific autophagy inhibitor 3-MA prevents both LC3 I/LC3 II conversion and HUVEC cell death. Finally, early removal of Bortezomib is accompanied by the recovery of cell shape and viability. These findings strongly suggest that Bortezomib induces either apoptosis or autophagy in EC; interfering with the autophagic response may potentiate the antiangiogenic effect of the drug.

  5. Networked T cell death following macrophage infection by Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Stephen H-F Macdonald

    Full Text Available BACKGROUND: Depletion of T cells following infection by Mycobacterium tuberculosis (Mtb impairs disease resolution, and interferes with clinical test performance that relies on cell-mediated immunity. A number of mechanisms contribute to this T cell suppression, such as activation-induced death and trafficking of T cells out of the peripheral circulation and into the diseased lungs. The extent to which Mtb infection of human macrophages affects T cell viability however, is not well characterised. METHODOLOGY/PRINCIPAL FINDINGS: We found that lymphopenia (<1.5 × 10(9 cells/l was prevalent among culture-positive tuberculosis patients, and lymphocyte counts significantly improved post-therapy. We previously reported that Mtb-infected human macrophages resulted in death of infected and uninfected bystander macrophages. In the current study, we sought to examine the influence of infected human alveolar macrophages on T cells. We infected primary human alveolar macrophages (the primary host cell for Mtb or PMA-differentiated THP-1 cells with Mtb H37Ra, then prepared cell-free supernatants. The supernatants of Mtb-infected macrophages caused dose-dependent, caspase-dependent, T cell apoptosis. This toxic effect of infected macrophage secreted factors did not require TNF-α or Fas. The supernatant cytotoxic signal(s were heat-labile and greater than 50 kDa in molecular size. Although ESAT-6 was toxic to T cells, other Mtb-secreted factors tested did not influence T cell viability; nor did macrophage-free Mtb bacilli or broth from Mtb cultures. Furthermore, supernatants from Mycobacterium bovis Bacille de Calmette et Guerin (BCG- infected macrophages also elicited T cell death suggesting that ESAT-6 itself, although cytotoxic, was not the principal mediator of T cell death in our system. CONCLUSIONS: Mtb-Infected macrophages secrete heat-labile factors that are toxic to T cells, and may contribute to the immunosuppression seen in tuberculosis as well as

  6. Heterogeneity reduces sensitivity of cell death for TNF-Stimuli

    Directory of Open Access Journals (Sweden)

    Schliemann Monica

    2011-12-01

    Full Text Available Abstract Background Apoptosis is a form of programmed cell death essential for the maintenance of homeostasis and the removal of potentially damaged cells in multicellular organisms. By binding its cognate membrane receptor, TNF receptor type 1 (TNF-R1, the proinflammatory cytokine Tumor Necrosis Factor (TNF activates pro-apoptotic signaling via caspase activation, but at the same time also stimulates nuclear factor κB (NF-κB-mediated survival pathways. Differential dose-response relationships of these two major TNF signaling pathways have been described experimentally and using mathematical modeling. However, the quantitative analysis of the complex interplay between pro- and anti-apoptotic signaling pathways is an open question as it is challenging for several reasons: the overall signaling network is complex, various time scales are present, and cells respond quantitatively and qualitatively in a heterogeneous manner. Results This study analyzes the complex interplay of the crosstalk of TNF-R1 induced pro- and anti-apoptotic signaling pathways based on an experimentally validated mathematical model. The mathematical model describes the temporal responses on both the single cell level as well as the level of a heterogeneous cell population, as observed in the respective quantitative experiments using TNF-R1 stimuli of different strengths and durations. Global sensitivity of the heterogeneous population was quantified by measuring the average gradient of time of death versus each population parameter. This global sensitivity analysis uncovers the concentrations of Caspase-8 and Caspase-3, and their respective inhibitors BAR and XIAP, as key elements for deciding the cell's fate. A simulated knockout of the NF-κB-mediated anti-apoptotic signaling reveals the importance of this pathway for delaying the time of death, reducing the death rate in the case of pulse stimulation and significantly increasing cell-to-cell variability. Conclusions Cell

  7. Molecular Control of Interdigital Cell Death and Cell Differentiation by Retinoic Acid during Digit Development

    Directory of Open Access Journals (Sweden)

    Martha Elena Díaz-Hernández

    2014-04-01

    Full Text Available The precise coordination of cell death and cell differentiation during the formation of developing digits is essential for generating properly shaped limbs. Retinoic acid (RA has a fundamental role in digit development; it promotes or inhibits the molecular expression of several critical genes. This control of gene expression establishes molecular cascades that enable both the commencement of cell death and the inhibition of cell differentiation. In this review, we focus on the antagonistic functions between RA and fibroblast growth factor (FGF signaling in the control of cell death and between RA and transforming growth factor beta (TGFβ signaling in the control of cell differentiation.

  8. T315 Decreases Acute Myeloid Leukemia Cell Viability through a Combination of Apoptosis Induction and Autophagic Cell Death

    Directory of Open Access Journals (Sweden)

    Chang-Fang Chiu

    2016-08-01

    Full Text Available T315, an integrin-linked kinase (ILK inhibitor, has been shown to suppress the proliferation of breast cancer, stomach cancer and chronic lymphocytic leukemia cells. Here we demonstrate that T315 decreases cell viability of acute myeloid leukemia (AML cell lines (HL-60 and THP-1 and primary leukemia cells from AML patients in a dose-responsive manner. Normal human bone marrow cells are less sensitive than leukemia cells to T315. T315 down regulates protein kinase B (Akt and p-Akt and induces caspase activation, poly-ADP-ribose polymerase (PARP cleavage, apoptosis and autophagy through an ILK-independent manner. Interestingly, pretreatment with autophagy inhibitors rescues cells from apoptosis and concomitant PARP cleavage, which implicates a key role of autophagic cell death in T315-mediated cytotoxicity. T315 also demonstrates efficacy in vivo, suppressing the growth of THP-1 xenograft tumors in athymic nude mice when administered intraperitoneally. This study shows that autophagic cell death and apoptosis cooperatively contribute to the anticancer activity of T315 in AML cells. In conclusion, the complementary roles of apoptotic and autophagic cell death should be considered in the future assessment of the translational value of T315 in AML therapy.

  9. Nek5 interacts with mitochondrial proteins and interferes negatively in mitochondrial mediated cell death and respiration.

    Science.gov (United States)

    Melo Hanchuk, Talita D; Papa, Priscila Ferreira; La Guardia, Paolo G; Vercesi, Anibal E; Kobarg, Jörg

    2015-06-01

    Mitochondria are involved in energy supply, signaling, cell death and cellular differentiation and have been implicated in several human diseases. Neks (NIMA-related kinases) represent a family of mammal protein kinases that play essential roles in cell-cycle progression, but other functions have recently been related. A yeast two-hybrid (Y2H) screen was performed to identify and characterize Nek5 interaction partners and the mitochondrial proteins Cox11, MTX-2 and BCLAF1 were retrieved. Apoptosis assay showed protective effects of stable hNek5 expression from Hek293-T's cell death after thapsigargin treatment (2 μM). Nek5 silenced cells as well as cells expressing a "kinase dead" version of Nek5, displayed an increase in ROS formation after 4 h of thapsigargin treatment. Mitochondrial respiratory chain activity was found decreased upon stable hNek5expression. Cells silenced for hNek5 on the other hand presented 1.7 fold increased basal rates of respiration, especially at the electrons transfer steps from TMPD to cytochrome c and at the complex II. In conclusion, our data suggest for the first time mitochondrial localization and functions for Nek5 and its participation in cell death and cell respiration regulation. Stable expression of hNek5 in Hek293T cells resulted in enhanced cell viability, decreased cell death and drug resistance, while depletion of hNek5by shRNA overcame cancer cell drug resistance and induced apoptosis in vitro. Stable expression of hNek5 also inhibits thapsigargin promoted apoptosis and the respiratory chain complex IV in HEK293T cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Melatonin Modulates Neuronal Cell Death Induced by Endoplasmic Reticulum Stress under Insulin Resistance Condition

    Directory of Open Access Journals (Sweden)

    Juhyun Song

    2017-06-01

    Full Text Available Insulin resistance (IR is an important stress factor in the central nervous system, thereby aggravating neuropathogenesis and triggering cognitive decline. Melatonin, which is an antioxidant phytochemical and synthesized by the pineal gland, has multiple functions in cellular responses such as apoptosis and survival against stress. This study investigated whether melatonin modulates the signaling of neuronal cell death induced by endoplasmic reticulum (ER stress under IR condition using SH-SY5Y neuroblastoma cells. Apoptosis cell death signaling markers (cleaved Poly [ADP-ribose] polymerase 1 (PARP, p53, and Bax and ER stress markers (phosphorylated eIF2α (p-eIF2α, ATF4, CHOP, p-IRE1, and spliced XBP1 (sXBP1 were measured using reverse transcription-PCR, quantitative PCR, and western blottings. Immunofluorescence staining was also performed for p-ASK1 and p-IRE1. The mRNA or protein expressions of cell death signaling markers and ER stress markers were increased under IR condition, but significantly attenuated by melatonin treatment. Insulin-induced activation of ASK1 (p-ASK1 was also dose dependently attenuated by melatonin treatment. The regulatory effect of melatonin on neuronal cells under IR condition was associated with ASK1 signaling. In conclusion, the result suggested that melatonin may alleviate ER stress under IR condition, thereby regulating neuronal cell death signaling.

  11. Autophagy modulates endoplasmic reticulum stress-induced cell death in podocytes: a protective role.

    Science.gov (United States)

    Cheng, Yu-Chi; Chang, Jer-Ming; Chen, Chien-An; Chen, Hung-Chun

    2015-04-01

    Endoplasmic reticulum stress occurs in a variety of patho-physiological mechanisms and there has been great interest in managing this pathway for the treatment of clinical diseases. Autophagy is closely interconnected with endoplasmic reticulum stress to counteract the possible injurious effects related with the impairment of protein folding. Studies have shown that glomerular podocytes exhibit high rate of autophagy to maintain as terminally differentiated cells. In this study, podocytes were exposed to tunicamycin and thapsigargin to induce endoplasmic reticulum stress. Thapsigargin/tunicamycin treatment induced a significant increase in endoplasmic reticulum stress and of cell death, represented by higher GADD153 and GRP78 expression and propidium iodide flow cytometry, respectively. However, thapsigargin/tunicamycin stimulation also enhanced autophagy development, demonstrated by monodansylcadaverine assay and LC3 conversion. To evaluate the regulatory effects of autophagy on endoplasmic reticulum stress-induced cell death, rapamycin (Rap) or 3-methyladenine (3-MA) was added to enhance or inhibit autophagosome formation. Endoplasmic reticulum stress-induced cell death was decreased at 6 h, but was not reduced at 24 h after Rap+TG or Rap+TM treatment. In contrast, endoplasmic reticulum stress-induced cell death increased at 6 and 24 h after 3-MA+TG or 3-MA+TM treatment. Our study demonstrated that thapsigargin/tunicamycin treatment induced endoplasmic reticulum stress which resulted in podocytes death. Autophagy, which counteracted the induced endoplasmic reticulum stress, was simultaneously enhanced. The salvational role of autophagy was supported by adding Rap/3-MA to mechanistically regulate the expression of autophagy and autophagosome formation. In summary, autophagy helps the podocytes from cell death and may contribute to sustain the longevity as a highly differentiated cell lineage. © 2014 by the Society for Experimental Biology and Medicine.

  12. Molecular and Translational Classifications of DAMPs in Immunogenic Cell Death

    Directory of Open Access Journals (Sweden)

    Abhishek D Garg

    2015-11-01

    Full Text Available The immunogenicity of malignant cells has recently been acknowledged as a critical determinant of efficacy in cancer therapy. Thus, besides developing direct immunostimulatory regimens including dendritic cell-based vaccines, checkpoint-blocking therapies, and adoptive T-cell transfer, researchers have started to focus on the overall immunobiology of neoplastic cells. It is now clear that cancer cells can succumb to some anticancer therapies by undergoing a peculiar form of cell death that is characterized by an increased immunogenic potential, owing to the emission of so-called damage-associated molecular patterns (DAMPs. The emission of DAMPs and other immunostimulatory factors by cells succumbing to immunogenic cell death (ICD favors the establishment of a productive interface with the immune system. This results in the elicitation of tumor-targeting immune responses associated with the elimination of residual, treatment-resistant cancer cells, as well as with the establishment of immunological memory. Although ICD has been characterized with increased precision since its discovery, several questions remain to be addressed. Here, we summarize and tabulate the main molecular, immunological, preclinical and clinical aspects of ICD, in an attempt to capture the essence of this clinically relevant phenomenon, and identify future challenges for this rapidly expanding field of investigation.

  13. Blockade of maitotoxin-induced oncotic cell death reveals zeiosis

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    Schilling William P

    2002-01-01

    Full Text Available Abstract Background Maitotoxin (MTX initiates cell death by sequentially activating 1 Ca2+ influx via non-selective cation channels, 2 uptake of vital dyes via formation of large pores, and 3 release of lactate dehydrogenase, an indication of cell lysis. MTX also causes formation of membrane blebs, which dramatically dilate during the cytolysis phase. To determine the role of phospholipase C (PLC in the cell death cascade, U73122, a specific inhibitor of PLC, and U73343, an inactive analog, were examined on MTX-induced responses in bovine aortic endothelial cells. Results Addition of either U73122 or U73343, prior to MTX, produced a concentration-dependent inhibition of the cell death cascade (IC50 ≈ 1.9 and 0.66 μM, respectively suggesting that the effect of these agents was independent of PLC. Addition of U73343 shortly after MTX, prevented or attenuated the effects of the toxin, but addition at later times had little or no effect. Time-lapse videomicroscopy showed that U73343 dramatically altered the blebbing profile of MTX-treated cells. Specifically, U73343 blocked bleb dilation and converted the initial blebbing event into "zeiosis", a type of membrane blebbing commonly associated with apoptosis. Cells challenged with MTX and rescued by subsequent addition of U73343, showed enhanced caspase-3 activity 48 hr after the initial insult, consistent with activation of the apoptotic program. Conclusions Within minutes of MTX addition, endothelial cells die by oncosis. Rescue by addition of U73343 shortly after MTX showed that a small percentage of cells are destined to die by oncosis, but that a larger percentage survive; cells that survive the initial insult exhibit zeiosis and may ultimately die by apoptotic mechanisms.

  14. Antitumor agent 25-epi Ritterostatin GN1N induces endoplasmic reticulum stress and autophagy mediated cell death in melanoma cells.

    Science.gov (United States)

    Riaz Ahmed, Kausar Begam; Kanduluru, Ananda Kumar; Feng, Li; Fuchs, Philip L; Huang, Peng

    2017-05-01

    Metastatic melanoma is the most aggressive of all skin cancers and is associated with poor prognosis owing to lack of effective treatments. 25-epi Ritterostatin GN1N is a novel antitumor agent with yet undefined mechanisms of action. We sought to delineate the antitumor mechanisms of 25-epi Ritterostatin GN1N in melanoma cells to determine the potential of this compound as a treatment for melanoma. Activation of the endoplasmic reticulum (ER) stress protein glucose-regulated protein 78 (GRP78) has been associated with increased melanoma progression, oncogenic signaling, drug resistance, and suppression of cell death. We found that 25-epi Ritterostatin GN1N induced cell death in melanoma cells at nanomolar concentrations, and this cell death was characterized by inhibition of GRP78 expression, increased expression of the ER stress marker CHOP, loss of mitochondrial membrane potential, and lipidation of the autophagy marker protein LC3B. Importantly, normal melanocytes exhibited limited sensitivity to 25-epi Ritterostatin GN1N. Subsequent in vivo results demonstrated that 25-epi Ritterostatin GN1N reduced melanoma growth in mouse tumor xenografts and did not affect body weight, suggesting minimal toxicity. In summary, our findings indicate that 25-epi Ritterostatin GN1N causes ER stress and massive autophagy, leading to collapse of mitochondrial membrane potential and cell death in melanoma cells, with minimal effects in normal melanocytes. Thus, 25-epi Ritterostatin GN1N is a promising anticancer agent that warrants further investigation.

  15. Augmented trophoblast cell death in preeclampsia can proceed via ceramide-mediated necroptosis.

    Science.gov (United States)

    Bailey, Liane Jennifer; Alahari, Sruthi; Tagliaferro, Andrea; Post, Martin; Caniggia, Isabella

    2017-02-02

    Preeclampsia, a serious hypertensive disorder of pregnancy, is characterized by elevated ceramide (CER) content that is responsible for heightened trophoblast cell death rates via apoptosis and autophagy. Whether trophoblast cells undergo necroptosis, a newly characterized form of regulated necrosis, and the potential role of CER in this process remain to be established. Herein, we report that exposure of both JEG3 cells and primary isolated cytotrophoblasts to C16:0 CER in conjunction with a caspase-8 inhibitor (Q-VD-OPh) promoted necroptotic cell death, as evidenced by increased expression and association of receptor-interacting protein kinases RIP1 and RIP3, as well as phosphorylation of mixed lineage kinase domain-like (MLKL) protein. MLKL activation and oligomerization could be abrogated by pretreatment with the necroptosis inhibitor necrostatin-1 (Nec-1). CER+Q-VD-OPH-treated primary trophoblasts displayed striking necrotic morphology along with disrupted fusion processes as evidenced by maintenance of E-cadherin-stained membrane boundaries and reduced glial cell missing-1 expression, but these events were effectively reversed using Nec-1. Of clinical relevance, we established an increased susceptibility to necroptotic cell death in preeclamptic placentae relative to normotensive controls. In preeclampsia, increased necrosome (RIP1/RIP3) protein levels, as well as MLKL activation and oligomerization associated with necrotic cytotrophoblast morphology. In addition, caspase-8 activity was reduced in severe early-onset preeclampsia cases. This study is the first to report that trophoblast cells undergo CER-induced necroptotic cell death, thereby contributing to the increased placental dysfunction and cell death found in preeclampsia.

  16. Cell swelling and volume regulation

    DEFF Research Database (Denmark)

    Hoffmann, Else Kay

    1992-01-01

    The extracellular space in the brain is typically 20% of the tissue volume and is reduced to at least half its size under conditions of neural insult. Whether there is a minimum size to the extracellular space was discussed. A general model for cell volume regulation was presented, followed...... by a discussion on how many of the generally involved mechanisms are identified in neural cells and (or) in astrocytes. There seems to be clear evidence suggesting that parallel K+ and Cl- channels mediate regulatory volume decrease in primary cultures of astrocytes, and a stretch-activated cation channel has...... been reported. The role of the different channels was discussed. A taurine leak pathway is clearly activated after cell swelling both in astrocytes and in neurones. The relations between the effect of glutamate and cell swelling were discussed. Discussion on the clearance of potassium from...

  17. Singapore grouper iridovirus, a large DNA virus, induces nonapoptotic cell death by a cell type dependent fashion and evokes ERK signaling.

    Science.gov (United States)

    Huang, Xiaohong; Huang, Youhua; Ouyang, Zhengliang; Xu, Lixiao; Yan, Yang; Cui, Huachun; Han, Xin; Qin, Qiwei

    2011-08-01

    Virus induced cell death, including apoptosis and nonapoptotic cell death, plays a critical role in the pathogenesis of viral diseases. Singapore grouper iridovirus (SGIV), a novel iridovirus of genus Ranavirus, causes high mortality and heavy economic losses in grouper aquaculture. Here, using fluorescence microscopy, electron microscopy and biochemical assays, we found that SGIV infection in host (grouper spleen, EAGS) cells evoked nonapoptotic programmed cell death (PCD), characterized by appearance of cytoplasmic vacuoles and distended endoplasmic reticulum, in the absence of DNA fragmentation, apoptotic bodies and caspase activation. In contrast, SGIV induced typical apoptosis in non-host (fathead minnow, FHM) cells, as evidenced by caspase activation and DNA fragmentation, suggesting that SGIV infection induced nonapoptotic cell death by a cell type dependent fashion. Furthermore, viral replication was essential for SGIV induced nonapoptotic cell death, but not for apoptosis. Notably, the disruption of mitochondrial transmembrane potential (ΔΨm) and externalization of phosphatidylserine (PS) were not detected in EAGS cells but in FHM cells after SGIV infection. Moreover, the extracellular signal-regulated kinase (ERK) signaling was involved in SGIV infection induced nonapoptotic cell death and viral replication. This is a first demonstration of ERK-mediated nonapoptotic cell death induced by a DNA virus. These findings contribute to understanding the mechanisms of iridovirus pathogenesis.

  18. Ouabain-induced perturbations in intracellular ionic homeostasis regulate death receptor-mediated apoptosis

    Science.gov (United States)

    Panayiotidis, Mihalis I.; Franco, Rodrigo; Bortner, Carl D.; Cidlowski, John A.

    2012-01-01

    Apoptosis is defined by specific morphological and biochemical characteristics including cell shrinkage (termed apoptotic volume decrease), a process that results from the regulation of ion channels and plasma membrane transporter activity. The Na+-K+-ATPase is the predominant pump that controls cell volume and plasma membrane potential in cells and alterations in its function have been suggested to be associated with apoptosis. We report here that the Na+-K+-ATPase inhibitor ouabain, potentiates apoptosis in the human lymphoma Jurkat cells exposed to Fas ligand (FasL) or Tumor necrosis factor--related apoptosis-inducing ligand (TRAIL) but not other apoptotic agents such as H2O2, thapsigargin or UV-C implicating a role for the Na+-K+-ATPase in death receptor-induced apoptosis. Interestingly, ouabain also potentiated perturbations in cell Ca2+ homeostasis only in conjunction with the apoptotic inducer FasL but not TRAIL. Ouabain did not affect alterations in the intracellular Ca2+ levels in response to H2O2, thapsigargin or UV-C. FasL-induced alterations in Ca2+ were not abolished in Ca2+-free medium but incubation of cells with BAPTA-AM inhibited both Ca2+ perturbations and the ouabain-induced potentiation of FasL-induced apoptosis. Our data suggest that the impairment of the Na+-K+-ATPase activity during apoptosis is linked to perturbations in cell Ca2+ homeostasis that modulate apoptosis induced by the activation of Fas by FasL. PMID:20422450

  19. Hepatocyte growth factor enhances death receptor-induced apoptosis by up-regulating DR5

    Directory of Open Access Journals (Sweden)

    Goodwin C Rory

    2008-11-01

    Full Text Available Abstract Background Hepatocyte growth factor (HGF and its receptor c-MET are commonly expressed in malignant gliomas and embryonic neuroectodermal tumors including medulloblastoma and appear to play an important role in the growth and dissemination of these malignancies. Dependent on cell context and the involvement of specific downstream effectors, both pro- and anti-apoptotic effects of HGF have been reported. Methods Human medulloblastoma cells were treated with HGF for 24–72 hours followed by death receptor ligand TRAIL (Tumor necrosis factor-related apoptosis-inducing ligand for 24 hours. Cell death was measured by MTT and Annexin-V/PI flow cytometric analysis. Changes in expression levels of targets of interest were measured by Northern blot analysis, quantitative reverse transcription-PCR, Western blot analysis as well as immunoprecipitation. Results In this study, we show that HGF promotes medulloblastoma cell death induced by TRAIL. TRAIL alone triggered apoptosis in DAOY cells and death was enhanced by pre-treating the cells with HGF for 24–72 h prior to the addition of TRAIL. HGF (100 ng/ml enhanced TRAIL (10 ng/ml induced cell death by 36% (P Conclusion Taken together, these and previous findings indicate that HGF:c-Met pathway either promotes or inhibits medulloblastoma cell death via pathway and context specific mechanisms.

  20. Canthin-6-one induces cell death, cell cycle arrest and differentiation in human myeloid leukemia cells.

    Science.gov (United States)

    Vieira Torquato, Heron F; Ribeiro-Filho, Antonio C; Buri, Marcus V; Araújo Júnior, Roberto T; Pimenta, Renata; de Oliveira, José Salvador R; Filho, Valdir C; Macho, Antonio; Paredes-Gamero, Edgar J; de Oliveira Martins, Domingos T

    2017-04-01

    Canthin-6-one is a natural product isolated from various plant genera and from fungi with potential antitumor activity. In the present study, we evaluate the antitumor effects of canthin-6-one in human myeloid leukemia lineages. Kasumi-1 lineage was used as a model for acute myeloid leukemia. Cells were treated with canthin-6-one and cell death, cell cycle and differentiation were evaluated in both total cells (Lin+) and leukemia stem cell population (CD34+CD38-Lin-/low). Among the human lineages tested, Kasumi-1 was the most sensitive to canthin-6-one. Canthin-6-one induced cell death with apoptotic (caspase activation, decrease of mitochondrial potential) and necrotic (lysosomal permeabilization, double labeling of annexin V/propidium iodide) characteristics. Moreover, canthin-6-one induced cell cycle arrest at G0/G1 (7μM) and G2 (45μM) evidenced by DNA content, BrdU incorporation and cyclin B1/histone 3 quantification. Canthin-6-one also promoted differentiation of Kasumi-1, evidenced by an increase in the expression of myeloid markers (CD11b and CD15) and the transcription factor PU.1. Furthermore, a reduction of the leukemic stem cell population and clonogenic capability of stem cells were observed. These results show that canthin-6-one can affect Kasumi-1 cells by promoting cell death, cell cycle arrest and cell differentiation depending on concentration used. Canthin-6-one presents an interesting cytotoxic activity against leukemic cells and represents a promising scaffold for the development of molecules for anti-leukemic applications, especially by its anti-leukemic stem cell activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Galectin-3 promotes caspase-independent cell death of HIV-1-infected macrophages.

    Science.gov (United States)

    Xue, Jing; Fu, Chunyan; Cong, Zhe; Peng, Lingjuan; Peng, Zhuoying; Chen, Ting; Wang, Wei; Jiang, Hong; Wei, Qiang; Qin, Chuan

    2017-01-01

    HIV-1-infected macrophages are a key contributor to the formation of a viral reservoir and new treatment strategies focus on eliminating this pool of virus. Galectin-3 is a potent apoptosis-inducing protein that regulates diverse cellular activities. In the present study, we investigated whether galectin-3 could induce cell death in HIV-1-infected macrophages using HIV-1-infected THP1 monocytes (THP1-MNs) and THP1-derived macrophages (THP1-MΦs) as in vitro cellular models. We found that THP1-MΦs were more resistant than the THP1-MNs to HIV-1 infection-induced death, and that HIV-1 infection of the THP1-MΦs increased expression of the anti-apoptotic proteins Mcl-1, Bcl-2 and Bcl-xL. Additionally, galectin-3 but not FasL, tumor necrosis factor (TNF)-related apoptosis-inducing ligand or TNF-α, could induce cell death in HIV-1-infected THP1-MΦs. A similar result was shown for primary human monocyte-derived macrophages. Galectin-3-induced cell death was also significantly increased in macrophages obtained from SIVmac251-infected macaques compared to that of macrophages from healthy macaques. Furthermore, galectin-3-induced cell death in HIV-1-infected THP1-MΦs was caspase independent. Interestingly, endonuclease G (Endo G) was increased in the nucleus and decreased in the cytoplasm of galectin-3-treated cells; thus, galectin-3-induced cell death in HIV-1-infected THP1-MΦs is most likely related to the translocation of Endo G from the cytoplasm to the nucleus. These findings suggest that galectin-3 may potentially aid in the eradication of HIV-1/SIV-infected macrophages. © 2016 Federation of European Biochemical Societies.

  2. Flow cytometry in the study of cell death

    Directory of Open Access Journals (Sweden)

    Álvaro L Bertho

    2000-06-01

    Full Text Available In this report we present a concise review concerning the use of flow cytometric methods to characterize and differentiate between two different mechanisms of cell death, apoptosis and necrosis. The applications of these techniques to clinical and basic research are also considered. The following cell features are useful to characterize the mode of cell death: (1 activation of an endonuclease in apoptotic cells results in extraction of the low molecular weight DNA following cell permeabilization, which, in turn, leads to their decreased stainability with DNA-specific fluorochromes. Measurements of DNA content make it possible to identify apoptotic cells and to recognize the cell cycle phase specificity of apoptotic process; (2 plasma membrane integrity, which is lost in necrotic but not in apoptotic cells; (3 the decrease in forward light scatter, paralleled either by no change or an increase in side scatter, represent early changes during apoptosis. The data presented indicate that flow cytometry can be applied to basic research of the molecular and biochemical mechanisms of apoptosis, as well as in the clinical situations, where the ability to monitor early signs of apoptosis in some systems may be predictive for the outcome of some treatment protocols.

  3. Immunohistochemistry of Programmed Cell Death in Archival Human Pathology Specimens

    Directory of Open Access Journals (Sweden)

    Takami Matsuyama

    2012-05-01

    Full Text Available Immunohistochemistry (IHC for detecting key signal molecules involved in programmed cell death (PCD in archival human pathology specimens is fairly well established. Detection of cleaved caspase-3 in lymphocytes in rheumatoid arthritis (RA and gastric surface foveolar glandular epithelia but not in synoviocytes in RA, gastric fundic glandular epithelia, or nasal NK/T-cell lymphoma (NKTCL cells suggests anti-apoptotic mechanisms in cell differentiation and in oncogenesis such as the induction of survivin. Enzymatically pretreated and ultra-super sensitive detection of beclin-1 in synoviocytes in RA and gastric fundic glandular epithelia suggests enhanced autophagy. The deposition of beclin-1 in fibrinoid necrosis in RA and expression of beclin-1 in detached gastric fundic glandular cells suggest that enhanced autophagy undergoes autophagic cell death (ACD. NKTCL exhibited enhanced autophagy through LC3 labeling and showed densely LC3 labeled cell-debris in regions of peculiar necrosis without deposition of beclin-1, indicating massive ACD in NKTCL and the alternative pathway enhancing autophagy following autophagic vesicle nucleation. Autophagy progression was monitored by labeling aggregated mitochondria and cathepsin D. The cell-debris in massive ACD in NKTCL were positive for 8-hydroxydeoxyguanosine, suggesting DNA oxidation occurred in ACD. Immunohistochemical autophagy and PCD analysis in archival human pathology specimens may offer new insights into autophagy in humans.

  4. Pinacidil and levamisole prevent glutamate-induced death of hippocampal neuronal cells through reducing ROS production.

    Science.gov (United States)

    Shukry, Mustafa; Kamal, Tarek; Ali, Radi; Farrag, Foad; Almadaly, Essam; Saleh, Ayman A; Abu El-Magd, Mohammed

    2015-10-01

    Activators of both adenosine 5'-triphosphate (ATP)-sensitive K(+) (KATP) channel and cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel have significant in vivo and in vitro neuroprotection against glutamate-induced death of some neuronal cells. Here, the effect of the KATP channel activator, pinacidil, and the CFTR Cl(-) channel opener, levamisole, against glutamate-induced oxidative stress were investigated in mouse hippocampal cells, HT22. The results from cell viability assay (WST-1) showed that pinacidil and levamisole weakly protected cells against glutamate-induced toxicity at 10 μM and their effect increased in a dose-dependent manner till reach maximum protection at 300 μM. Pretreatment with pinacidil or levamisole significantly suppressed the elevation of reactive oxygen species (ROS) triggered by glutamate through stabilising mitochondrial membrane potential and subsequently protected HT22 cells against glutamate-induced death. HT22 cells viability was maintained by pinacidil and levamisole in presence of glutathione inhibitor, BSO. Also, pinacidil and levamisole pretreatment did not induce recovery of glutathione levels decreased by glutamate Expectedly, this protection was abolished by the KATP and CFTR Cl(-) channels blocker, glibenclamide. Thus, both pinacidil and levamisole protect HT22 cells against glutamate-induced cell death through stabilising mitochondrial membrane potential and subsequently decreasing ROS production.

  5. Bee Venom Protects against Rotenone-Induced Cell Death in NSC34 Motor Neuron Cells.

    Science.gov (United States)

    Jung, So Young; Lee, Kang-Woo; Choi, Sun-Mi; Yang, Eun Jin

    2015-09-21

    Rotenone, an inhibitor of mitochondrial complex I of the mitochondrial respiratory chain, is known to elevate mitochondrial reactive oxygen species and induce apoptosis via activation of the caspase-3 pathway. Bee venom (BV) extracted from honey bees has been widely used in oriental medicine and contains melittin, apamin, adolapin, mast cell-degranulating peptide, and phospholipase A₂. In this study, we tested the effects of BV on neuronal cell death by examining rotenone-induced mitochondrial dysfunction. NSC34 motor neuron cells were pretreated with 2.5 μg/mL BV and stimulated with 10 μM rotenone to induce cell toxicity. We assessed cell death by Western blotting using specific antibodies, such as phospho-ERK1/2, phospho-JNK, and cleaved capase-3 and performed an MTT assay for evaluation of cell death and mitochondria staining. Pretreatment with 2.5 μg/mL BV had a neuroprotective effect against 10 μM rotenone-induced cell death in NSC34 motor neuron cells. Pre-treatment with BV significantly enhanced cell viability and ameliorated mitochondrial impairment in rotenone-treated cellular model. Moreover, BV treatment inhibited the activation of JNK signaling and cleaved caspase-3 related to cell death and increased ERK phosphorylation involved in cell survival in rotenone-treated NSC34 motor neuron cells. Taken together, we suggest that BV treatment can be useful for protection of neurons against oxidative stress or neurotoxin-induced cell death.

  6. Bee Venom Protects against Rotenone-Induced Cell Death in NSC34 Motor Neuron Cells

    Directory of Open Access Journals (Sweden)

    So Young Jung

    2015-09-01

    Full Text Available Rotenone, an inhibitor of mitochondrial complex I of the mitochondrial respiratory chain, is known to elevate mitochondrial reactive oxygen species and induce apoptosis via activation of the caspase-3 pathway. Bee venom (BV extracted from honey bees has been widely used in oriental medicine and contains melittin, apamin, adolapin, mast cell-degranulating peptide, and phospholipase A2. In this study, we tested the effects of BV on neuronal cell death by examining rotenone-induced mitochondrial dysfunction. NSC34 motor neuron cells were pretreated with 2.5 μg/mL BV and stimulated with 10 μM rotenone to induce cell toxicity. We assessed cell death by Western blotting using specific antibodies, such as phospho-ERK1/2, phospho-JNK, and cleaved capase-3 and performed an MTT assay for evaluation of cell death and mitochondria staining. Pretreatment with 2.5 μg/mL BV had a neuroprotective effect against 10 μM rotenone-induced cell death in NSC34 motor neuron cells. Pre-treatment with BV significantly enhanced cell viability and ameliorated mitochondrial impairment in rotenone-treated cellular model. Moreover, BV treatment inhibited the activation of JNK signaling and cleaved caspase-3 related to cell death and increased ERK phosphorylation involved in cell survival in rotenone-treated NSC34 motor neuron cells. Taken together, we suggest that BV treatment can be useful for protection of neurons against oxidative stress or neurotoxin-induced cell death.

  7. Non-canonical programmed cell death mechanisms triggered by natural compounds.

    Science.gov (United States)

    Diederich, Marc; Cerella, Claudia

    2016-10-01

    Natural compounds are the fundament of pharmacological treatments and more than 50% of all anticancer drugs are of natural origins or at least derived from scaffolds present in Nature. Over the last 25 years, molecular mechanisms triggered by natural anticancer compounds were investigated. Emerging research showed that molecules of natural origins are useful for both preventive and therapeutic purposes by targeting essential hallmarks and enabling characteristics described by Hanahan and Weinberg. Moreover, natural compounds were able to change the differentiation status of selected cell types. One of the earliest response of cells treated by pharmacologically active compounds is the change of its morphology leading to ultra-structural perturbations: changes in membrane composition, cytoskeleton integrity, alterations of the endoplasmic reticulum, mitochondria and of the nucleus lead to formation of morphological alterations that are a characteristic of both compound and cancer type preceding cell death. Apoptosis and autophagy were traditionally considered as the most prominent cell death or cell death-related mechanisms. By now multiple other cell death modalities were described and most likely involved in response to chemotherapeutic treatment. It can be hypothesized that especially necrosis-related phenotypes triggered by various treatments or evolving from apoptotic or autophagic mechanisms, provide a more efficient therapeutic outcome depending on cancer type and genetic phenotype of the patient. In fact, the recent discovery of multiple regulated forms of necrosis and the initial elucidation of the corresponding cell signaling pathways appear nowadays as important tools to clarify the immunogenic potential of non-canonical forms of cell death induction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Triggering cell death by nanographene oxide mediated hyperthermia

    Science.gov (United States)

    Vila, M.; Matesanz, M. C.; Gonçalves, G.; Feito, M. J.; Linares, J.; Marques, P. A. A. P.; Portolés, M. T.; Vallet-Regi, M.

    2014-01-01

    Graphene oxide (GO) has been proposed as an hyperthermia agent for anticancer therapies due to its near-infrared (NIR) optical absorption ability which, with its small two-dimensional size, could have a unique performance when compared to that of any other nanoparticle. Nevertheless, attention should be given to the hyperthermia route and the kind of GO-cell interactions induced in the process. The hyperthermia laser irradiation parameters, such as exposure time and laser power, were investigated to control the temperature rise and consequent damage in the GOs containing cell culture medium. The type of cell damage produced was evaluated as a function of these parameters. The results showed that cell culture temperature (after irradiating cells with internalized GO) increases preferentially with laser power rather than with exposure time. Moreover, when laser power is increased, necrosis is the preferential cell death leading to an increase of cytokine release to the medium.

  9. Different Types of Cell Death Induced by Enterotoxins

    Directory of Open Access Journals (Sweden)

    Ming-Yuan Hong

    2010-08-01

    Full Text Available The infection of bacterial organisms generally causes cell death to facilitate microbial invasion and immune escape, both of which are involved in the pathogenesis of infectious diseases. In addition to the intercellular infectious processes, pathogen-produced/secreted enterotoxins (mostly exotoxins are the major weapons that kill host cells and cause diseases by inducing different types of cell death, particularly apoptosis and necrosis. Blocking these enterotoxins with synthetic drugs and vaccines is important for treating patients with infectious diseases. Studies of enterotoxin-induced apoptotic and necrotic mechanisms have helped us to create efficient strategies to use against these well-characterized cytopathic toxins. In this article, we review the induction of the different types of cell death from various bacterial enterotoxins, such as staphylococcal enterotoxin B, staphylococcal alpha-toxin, Panton-Valentine leukocidin, alpha-hemolysin of Escherichia coli, Shiga toxins, cytotoxic necrotizing factor 1, heat-labile enterotoxins, and the cholera toxin, Vibrio cholerae. In addition, necrosis caused by pore-forming toxins, apoptotic signaling through cross-talk pathways involving mitochondrial damage, endoplasmic reticulum stress, and lysosomal injury is discussed.

  10. Cytokines in immunogenic cell death: Applications for cancer immunotherapy.

    Science.gov (United States)

    Showalter, Anne; Limaye, Arati; Oyer, Jeremiah L; Igarashi, Robert; Kittipatarin, Christina; Copik, Alicja J; Khaled, Annette R

    2017-09-01

    Despite advances in treatments like chemotherapy and radiotherapy, metastatic cancer remains a leading cause of death for cancer patients. While many chemotherapeutic agents can efficiently eliminate cancer cells, long-term protection against cancer is not achieved and many patients experience cancer recurrence. Mobilizing and stimulating the immune system against tumor cells is one of the most effective ways to protect against cancers that recur and/or metastasize. Activated tumor specific cytotoxic T lymphocytes (CTLs) can seek out and destroy metastatic tumor cells and reduce tumor lesions. Natural Killer (NK) cells are a front-line defense against drug-resistant tumors and can provide tumoricidal activity to enhance tumor immune surveillance. Cytokines like IFN-γ or TNF play a crucial role in creating an immunogenic microenvironment and therefore are key players in the fight against metastatic cancer. To this end, a group of anthracyclines or treatments like photodynamic therapy (PDT) exert their effects on cancer cells in a manner that activates the immune system. This process, known as immunogenic cell death (ICD), is characterized by the release of membrane-bound and soluble factors that boost the function of immune cells. This review will explore different types of ICD inducers, some in clinical trials, to demonstrate that optimizing the cytokine response brought about by treatments with ICD-inducing agents is central to promoting anti-cancer immunity that provides long-lasting protection against disease recurrence and metastasis. Copyright © 2017. Published by Elsevier Ltd.

  11. Anticancer Effect of Ginger Extract against Pancreatic Cancer Cells Mainly through Reactive Oxygen Species-Mediated Autotic Cell Death.

    Directory of Open Access Journals (Sweden)

    Miho Akimoto

    Full Text Available The extract of ginger (Zingiber officinale Roscoe and its major pungent components, [6]-shogaol and [6]-gingerol, have been shown to have an anti-proliferative effect on several tumor cell lines. However, the anticancer activity of the ginger extract in pancreatic cancer is poorly understood. Here, we demonstrate that the ethanol-extracted materials of ginger suppressed cell cycle progression and consequently induced the death of human pancreatic cancer cell lines, including Panc-1 cells. The underlying mechanism entailed autosis, a recently characterized form of cell death, but not apoptosis or necroptosis. The extract markedly increased the LC3-II/LC3-I ratio, decreased SQSTM1/p62 protein, and enhanced vacuolization of the cytoplasm in Panc-1 cells. It activated AMPK, a positive regulator of autophagy, and inhibited mTOR, a negative autophagic regulator. The autophagy inhibitors 3-methyladenine and chloroquine partially prevented cell death. Morphologically, however, focal membrane rupture, nuclear shrinkage, focal swelling of the perinuclear space and electron dense mitochondria, which are unique morphological features of autosis, were observed. The extract enhanced reactive oxygen species (ROS generation, and the antioxidant N-acetylcystein attenuated cell death. Our study revealed that daily intraperitoneal administration of the extract significantly prolonged survival (P = 0.0069 in a peritoneal dissemination model and suppressed tumor growth in an orthotopic model of pancreatic cancer (P < 0.01 without serious adverse effects. Although [6]-shogaol but not [6]-gingerol showed similar effects, chromatographic analyses suggested the presence of other constituent(s as active substances. Together, these results show that ginger extract has potent anticancer activity against pancreatic cancer cells by inducing ROS-mediated autosis and warrants further investigation in order to develop an efficacious candidate drug.

  12. Transcriptional control of non-apoptotic developmental cell death in C. elegans.

    Science.gov (United States)

    Malin, Jennifer A; Kinet, Maxime J; Abraham, Mary C; Blum, Elyse S; Shaham, Shai

    2016-12-01

    Programmed cell death is an essential aspect of animal development. Mutations in vertebrate genes that mediate apoptosis only mildly perturb development, suggesting that other cell death modes likely have important roles. Linker cell-type death (LCD) is a morphologically conserved cell death form operating during the development of Caenorhabditis elegans and vertebrates. We recently described a molecular network governing LCD in C. elegans, delineating a key role for the transcription factor heat-shock factor 1 (HSF-1). Although HSF-1 functions to protect cells from stress in many settings by inducing expression of protein folding chaperones, it promotes LCD by inducing expression of the conserved E2 ubiquitin-conjugating enzyme LET-70/UBE2D2, which is not induced by stress. Following whole-genome RNA interference and candidate gene screens, we identified and characterized four conserved regulators required for LCD. Here we show that two of these, NOB-1/Hox and EOR-1/PLZF, act upstream of HSF-1, in the context of Wnt signaling. A third protein, NHR-67/TLX/NR2E1, also functions upstream of HSF-1, and has a separate activity that prevents precocious expression of HSF-1 transcriptional targets. We demonstrate that the SET-16/mixed lineage leukemia 3/4 (MLL3/4) chromatin regulation complex functions at the same step or downstream of HSF-1 to control LET-70/UBE2D2 expression. Our results identify conserved proteins governing LCD, and demonstrate that transcriptional regulators influence this process at multiple levels.

  13. Cell birth, cell death, cell diversity and DNA breaks: how do they all fit together?

    Science.gov (United States)

    Gilmore, E. C.; Nowakowski, R. S.; Caviness, V. S. Jr; Herrup, K.

    2000-01-01

    Substantial death of migrating and differentiating neurons occurs within the developing CNS of mice that are deficient in genes required for repair of double-stranded DNA breaks. These findings suggest that large-scale, yet previously unrecognized, double-stranded DNA breaks occur normally in early postmitotic and differentiating neurons. Moreover, they imply that cell death occurs if the breaks are not repaired. The cause and natural function of such breaks remains a mystery; however, their occurrence has significant implications. They might be detected by histological methods that are sensitive to DNA fragmentation and mistakenly interpreted to indicate cell death when no relationship exists. In a broader context, there is now renewed speculation that DNA recombination might be occurring during neuronal development, similar to DNA recombination in developing lymphocytes. If this is true, the target gene(s) of recombination and their significance remain to be determined.

  14. Regulatory T cells and human myeloid dendritic cells promote tolerance via programmed death ligand-1.

    Directory of Open Access Journals (Sweden)

    Shoba Amarnath

    2010-02-01

    Full Text Available Immunotherapy using regulatory T cells (Treg has been proposed, yet cellular and molecular mechanisms of human Tregs remain incompletely characterized. Here, we demonstrate that human Tregs promote the generation of myeloid dendritic cells (DC with reduced capacity to stimulate effector T cell responses. In a model of xenogeneic graft-versus-host disease (GVHD, allogeneic human DC conditioned with Tregs suppressed human T cell activation and completely abrogated posttransplant lethality. Tregs induced programmed death ligand-1 (PD-L1 expression on Treg-conditioned DC; subsequently, Treg-conditioned DC induced PD-L1 expression in vivo on effector T cells. PD-L1 blockade reversed Treg-conditioned DC function in vitro and in vivo, thereby demonstrating that human Tregs can promote immune suppression via DC modulation through PD-L1 up-regulation. This identification of a human Treg downstream cellular effector (DC and molecular mechanism (PD-L1 will facilitate the rational design of clinical trials to modulate alloreactivity.

  15. Arctigenin preferentially induces tumor cell death under glucose deprivation by inhibiting cellular energy metabolism.

    Science.gov (United States)

    Gu, Yuan; Qi, Chunting; Sun, Xiaoxiao; Ma, Xiuquan; Zhang, Haohao; Hu, Lihong; Yuan, Junying; Yu, Qiang

    2012-08-15

    Selectively eradicating cancer cells with minimum adverse effects on normal cells is a major challenge in the development of anticancer therapy. We hypothesize that nutrient-limiting conditions frequently encountered by cancer cells in poorly vascularized solid tumors might provide an opportunity for developing selective therapy. In this study, we investigated the function and molecular mechanisms of a natural compound, arctigenin, in regulating tumor cell growth. We demonstrated that arctigenin selectively promoted glucose-starved A549 tumor cells to undergo necrosis by inhibiting mitochondrial respiration. In doing so, arctigenin elevated cellular level of reactive oxygen species (ROS) and blocked cellular energy metabolism in the glucose-starved tumor cells. We also demonstrated that cellular ROS generation was caused by intracellular ATP depletion and played an essential role in the arctigenin-induced tumor cell death under the glucose-limiting condition. Furthermore, we combined arctigenin with the glucose analogue 2-deoxyglucose (2DG) and examined their effects on tumor cell growth. Interestingly, this combination displayed preferential cell-death inducing activity against tumor cells compared to normal cells. Hence, we propose that the combination of arctigenin and 2DG may represent a promising new cancer therapy with minimal normal tissue toxicity. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  16. Microfluidic monitoring of programmed cell death in living plant seed tissue

    DEFF Research Database (Denmark)

    Mark, Christina; Heiskanen, Arto; Zor, Kinga

    Programmed cell death (PCD) is a highly regulated process in which cells are dismantled. Reactive oxygen species (ROS) are involved in PCD in plants, but the relationship between and mechanisms behind ROS and PCD are only poorly understood in plant cells compared to in animal cells (Gechev, Tsanko......, et al., (2006), BioEssays, 28, p. 1091). Microfluidic cell culture enables in vitro experiments to approach in vivo conditions. Combining microfluidics with the Lab-On-a-Chip concept allows implementing a wide range of assays for real-time monitoring of effects in a biological system of factors...... such as concentration of selected compounds, external pH, oxygen consumption, redox state and cell viability. The aleurone layer of the barley seed is a 2-3 single cell type thick tissue that can be dissected from the embryo and starchy endosperm. During incubation in vitro this mechanically very robust maintains...

  17. Cell death in the injured brain: roles of metallothioneins

    DEFF Research Database (Denmark)

    Pedersen, Mie Ø; Larsen, Agnete; Stoltenberg, Meredin

    2009-01-01

    oxygen species (ROS). ROS promote oxidative stress, which leads to neurodegeneration and ultimately results in programmed cell death (secondary injury). Since this delayed, secondary tissue loss occurs days to months following the primary injury it provides a therapeutic window where potential...... neuroprotective treatment could alleviate ongoing neurodegeneration, cell death and neurological impairment following TBI. Various neuroprotective drug candidates have been described, tested and proven effective in pre-clinical studies, including glutamate receptor antagonists, calcium-channel blockers......, and caspase inhibitors. However, most of the scientific efforts have failed in translating the experimental results into clinical trials. Despite intensive research, effective neuroprotective therapies are lacking in the clinic, and TBI continues to be a major cause of morbidity and mortality. This paper...

  18. The role of mitochondria in yeast programmed cell death

    Directory of Open Access Journals (Sweden)

    Nicoletta eGuaragnella

    2012-07-01

    Full Text Available Mammalian apoptosis and yeast programmed cell death (PCD share a variety of features including ROS production, protease activity and a major role played by mitochondria. In view of this, and of the distinctive characteristics differentiating yeast and multicellular organism PCD, the mitochondrial contribution to cell death in the genetically tractable yeast Saccharomyces cerevisiae has been intensively investigated. In this mini-review we report whether and how yeast mitochondrial function and proteins belonging to oxidative phosphorylation, protein trafficking into and out of mitochondria, and mitochondrial dynamics, play a role in PCD. Since in PCD many processes take place over time, emphasis will be placed on an experimental model based on acetic acid induced PCD (AA-PCD which has the unique feature of having been investigated as a function of time. As will be described there are at least two AA-PCD pathways each with a multifaceted role played by mitochondrial components, in particular by cytochrome c.

  19. Zanthoxylum fruit extract from Japanese pepper promotes autophagic cell death in cancer cells.

    Science.gov (United States)

    Nozaki, Reo; Kono, Toru; Bochimoto, Hiroki; Watanabe, Tsuyoshi; Oketani, Kaori; Sakamaki, Yuichi; Okubo, Naoto; Nakagawa, Koji; Takeda, Hiroshi

    2016-10-25

    Zanthoxylum fruit, obtained from the Japanese pepper plant (Zanthoxylum piperitum De Candolle), and its extract (Zanthoxylum fruit extract, ZFE) have multiple physiological activities (e.g., antiviral activity). However, the potential anticancer activity of ZFE has not been fully examined. In this study, we investigated the ability of ZFE to induce autophagic cell death (ACD). ZFE caused remarkable autophagy-like cytoplasmic vacuolization, inhibited cell proliferation, and ultimately induced cell death in the human cancer cell lines DLD-1, HepG2, and Caco-2, but not in A549, MCF-7, or WiDr cells. ZFE increased the level of LC3-II protein, a marker of autophagy. Knockdown of ATG5 using siRNA inhibited ZFE-induced cytoplasmic vacuolization and cell death. Moreover, in cancer cells that could be induced to undergo cell death by ZFE, the extract increased the phosphorylation of c-Jun N-terminal kinase (JNK), and the JNK inhibitor SP600125 attenuated both vacuolization and cell death. Based on morphology and expression of marker proteins, ZFE-induced cell death was neither apoptosis nor necrosis. Normal intestinal cells were not affected by ZFE. Taken together, our findings show that ZFE induces JNK-dependent ACD, which appears to be the main mechanism underlying its anticancer activity, suggesting a promising starting point for anticancer drug development.

  20. Using microfluidics to study programmed cell death: A new approach

    DEFF Research Database (Denmark)

    Mark, Christina; Zor, Kinga; Heiskanen, Arto

    This project focuses on applying microfluidic tissue culture for electrochemical or optical measurements during programmed cell death (PCD) in barley aleurone layer to increase understanding of the underlying mechanisms of PCD in plants. Microfluidic tissue culture enables in vitro experiments...... a double-fluorescent probe-system also used by Fath et al5. Future challenges include integrating both these systems into a microfluidic device for plant tissue culture....

  1. Targeted cancer cell death induced by biofunctionalized magnetic nanowires

    KAUST Repository

    Contreras, Maria F.

    2014-02-01

    Magnetic micro and nanomaterials are increasingly interesting for biomedical applications since they possess many advantageous properties: they can become biocompatible, they can be functionalized to target specific cells and they can be remotely manipulated by magnetic fields. The goal of this study is to use antibody-functionalized nickel nanowires (Ab-NWs) as an alternative method in cancer therapy overcoming the limitations of current treatments that lack specificity and are highly cytotoxic. Ab-NWs have been incubated with cancer cells and a 12% drop on cell viability was observed for a treatment of only 10 minutes and an alternating magnetic field of low intensity and low frequency. It is believed that the Ab-NWs vibrate transmitting a mechanical force to the targeted cells inducing cell death. © 2014 IEEE.

  2. Cell Death-Associated Molecular-Pattern Molecules: Inflammatory Signaling and Control

    Directory of Open Access Journals (Sweden)

    Beatriz Sangiuliano

    2014-01-01

    Full Text Available Apoptosis, necroptosis, and pyroptosis are different cellular death programs characterized in organs and tissues as consequence of microbes infection, cell stress, injury, and chemotherapeutics exposure. Dying and death cells release a variety of self-proteins and bioactive chemicals originated from cytosol, nucleus, endoplasmic reticulum, and mitochondria. These endogenous factors are named cell death-associated molecular-pattern (CDAMP, damage-associated molecular-pattern (DAMP molecules, and alarmins. Some of them cooperate or act as important initial or delayed inflammatory mediators upon binding to diverse membrane and cytosolic receptors coupled to signaling pathways for the activation of the inflammasome platforms and NF-κB multiprotein complexes. Current studies show that the nonprotein thiols and thiol-regulating enzymes as well as highly diffusible prooxidant reactive oxygen and nitrogen species released together in extracellular inflammatory milieu play essential role in controlling pro- and anti-inflammatory activities of CDAMP/DAMP and alarmins. Here, we provide an overview of these emerging concepts and mechanisms of triggering and maintenance of tissue inflammation under massive death of cells.

  3. The Na+/H+ exchanger NHE1 in stress-induced signal transduction: implications for cell proliferation and cell death

    DEFF Research Database (Denmark)

    Pedersen, Stine Falsig

    2006-01-01

    has expanded from one of a household protein involved in ion homeostasis to that of a multifaceted regulator and/or modulator of a wide variety of cell functions. NHE1 plays pivotal roles in response to a number of important physiological stress conditions which, in addition to cell shrinkage...... and acidification, include hypoxia and mechanical stimuli, such as cell stretch. It has recently become apparent that NHE1-mediated modulation of, e.g., cell migration, morphology, proliferation, and death results not only from NHE1-mediated changes in pHi, cell volume, and/or [Na+]i, but also from direct protein-protein...... interactions with, e.g., ezrin/radixin/moesin (ERM) proteins and regulation of cellular signaling events, including the activity of mitogen-activated protein kinases (MAPKs) and Akt/protein kinase B (PKB). The aim of this review is to present and discuss new findings implicating NHE1 activation as a central...

  4. Transcriptional regulation of the cell cycle

    NARCIS (Netherlands)

    Stahl, M.

    2006-01-01

    Transcriptional regulators play an important role during cell cycle progression. A subset of these even seems to have a critical function in regulating cell cycle transitions. In this thesis, I have addressed the importance of transcriptional control in the regulation of cell cycle progression, in

  5. Caspase-2 mediates a Brucella abortus RB51-induced hybrid cell death having features of apoptosis and pyroptosis.

    Science.gov (United States)

    Bronner, Denise N; O'Riordan, Mary X D; He, Yongqun

    2013-01-01

    Programmed cell death (PCD) can play a crucial role in tuning the immune response to microbial infection. Although PCD can occur in different forms, all are mediated by a family of proteases called caspases. Caspase-2 is the most conserved caspase, however, its function in cell death is ill-defined. Previously we demonstrated that live attenuated cattle vaccine strain Brucella abortus RB51 induces caspase-2-mediated and caspase-1-independent PCD of infected macrophages. We also discovered that rough attenuated B. suis strain VTRS1 induces a caspase-2-mediated and caspase-1-independent proinflammatory cell death in infected macrophages, which was tentatively coined "caspase-2-mediated pyroptosis". However, the mechanism of caspase-2-mediated cell death pathway remained unclear. In this study, we found that caspase-2 mediated proinflammatory cell death of RB51-infected macrophages and regulated many genes in different PCD pathways. We show that the activation of proapoptotic caspases-3 and -8 was dependent upon caspase-2. Caspase-2 regulated mitochondrial cytochrome c release and TNFα production, both of which are known to activate caspase-3 and caspase-8, respectively. In addition to TNFα, RB51-induced caspase-1 and IL-1β production was also driven by caspase-2-mediated mitochondrial dysfunction. Interestingly, pore formation, a phenomenon commonly associated with caspase-1-mediated pyroptosis, occurred; however, unlike its role in S. typhimurium-induced pyroptosis, pore formation did not contribute to RB51-induced proinflammatory cell death. Our data suggest that caspase-2 acts as an initiator caspase that mediates a novel RB51-induced hybrid cell death that simulates but differs from typical non-proinflammatory apoptosis and caspase-1-mediated proinflammatory pyroptosis. The initiator role of the caspase-2-mediated cell death was also conserved in cellular stress-induced cell death of macrophages treated with etoposide, naphthalene, or anti-Fas. Caspase-2 also

  6. Ethical considerations in the regulation of euthanasia and physician-assisted death in Canada.

    Science.gov (United States)

    Landry, Joshua T; Foreman, Thomas; Kekewich, Michael

    2015-11-01

    On February 6th 2015 the Supreme Court of Canada (SCC) released their decision on Carter v Canada (Attorney General) to uphold a judgment from a lower court which determined that the current prohibition in Canada on physician-assisted dying violated the s. 7 [Charter of Rights and Freedoms] rights of competent adults whose medical condition causes intolerable suffering. The purpose of this piece is to briefly examine current regulations from Oregon (USA), Belgium, and the Netherlands, in which physician-assisted death and/or euthanasia is currently permitted, as well as from the province of Quebec which recently passed Bill-52, "An Act Respecting End-of-Life Care." We present ethical considerations that would be pertinent in the development of policies and regulations across Canada in light of this SCC decision: patient and provider autonomy, determining a relevant decision-making standard for practice, and explicating challenges with the SCC criteria for assisted-death eligibility with special consideration to the provision of assisted-death, and review of assisted-death cases. [It is not the goal of this paper to address all questions related to the regulation and policy development of euthanasia and assisted death in Canada, but rather to stimulate and guide the conversations in these areas for policy makers, professional bodies, and regulators.]. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. HSpin1, a transmembrane protein interacting with Bcl-2/Bcl-xL, induces a caspase-independent autophagic cell death.

    Science.gov (United States)

    Yanagisawa, H; Miyashita, T; Nakano, Y; Yamamoto, D

    2003-07-01

    The Drosophila spinster (spin) gene product is required for programmed cell death in the nervous and reproductive systems. We have identified a human homologue of the Drosophila spin gene product (HSpin1). HSpin1 bound to Bcl-2 and apoptosis regulator Bcl-X (Bcl-xL), but not to proapoptotic members such as Bcl-2-associated X protein and Bcl-2 homologous antagonist killer, in cells treated with TNF-alpha. Exogenous expression of HSpin1 resulted in the cell death without inducing a release of cytochrome c from mitochondria. Overexpression of Bcl-xL inhibited the HSpin1-induced cell death. Interestingly, a necrosis inhibitor, pyrrolidine dithiocarbomate, but not the pancaspase inhibitors, carbobenzoxy-VAD-fluoromethyl ketone and p35, blocked the HSpin1-induced cell death. HSpin1-induced cell death increases autophagic vacuole and mature form of cathepsin D, suggesting a novel caspase-independent cell death, which is link to autophagy.

  8. In Vitro Cell Death Determination for Drug Discovery: A Landscape Review of Real Issues

    Directory of Open Access Journals (Sweden)

    Benoite Méry

    2017-02-01

    Full Text Available Cell death plays a crucial role for a myriad of physiological processes, and several human diseases such as cancer are characterized by its deregulation. There are many methods available for both quantifying and qualifying the accurate process of cell death which occurs. Choosing the right assay tool is essential to generate meaningful data, provide sufficient information for clinical applications, and understand cell death processes. In vitro cell death assays are important steps in the search for new therapies against cancer as the ultimate goal remains the elaboration of drugs that interfere with specific cell death mechanisms. However, choosing a cell viability or cytotoxicity assay among the many available options is a daunting task. Indeed, cell death can be approached by several viewpoints and require a more holistic approach. This review provides an overview of cell death assays usually used in vitro for assessing cell death so as to elaborate new potential chemotherapeutics and discusses considerations for using each assay.

  9. Control of nonapoptotic developmental cell death in Caenorhabditis elegans by a polyglutamine-repeat protein.

    Science.gov (United States)

    Blum, Elyse S; Abraham, Mary C; Yoshimura, Satoshi; Lu, Yun; Shaham, Shai

    2012-02-24

    Death is a vital developmental cell fate. In Caenorhabditis elegans, programmed death of the linker cell, which leads gonadal elongation, proceeds independently of caspases and apoptotic effectors. To identify genes promoting linker-cell death, we performed a genome-wide RNA interference screen. We show that linker-cell death requires the gene pqn-41, encoding an endogenous polyglutamine-repeat protein. pqn-41 functions cell-autonomously and is expressed at the onset of linker-cell death. pqn-41 expression is controlled by the mitogen-activated protein kinase kinase SEK-1, which functions in parallel to the zinc-finger protein LIN-29 to promote cellular demise. Linker-cell death is morphologically similar to cell death associated with normal vertebrate development and polyglutamine-induced neurodegeneration. Our results may therefore provide molecular inroads to understanding nonapoptotic cell death in metazoan development and disease.

  10. Cadmium-induced programmed cell death signaling in tomato suspension cells

    NARCIS (Netherlands)

    Yakimova, E.T.; Woltering, E.J.; Kapchina-Toteva, V.M.

    2009-01-01

    Here we present a summary of our study on cadmium-induced cell death signaling in a model system of suspension-cultured tomato cells. Exposure of the cells to CdSO4 induced typical for PCD (cytoplasm shrinkage and nuclear condensation) morphological changes of the dead cells. Ethylene and hydrogen

  11. Crystalline structure of pulverized dental calculus induces cell death in oral epithelial cells.

    Science.gov (United States)

    Ziauddin, S M; Yoshimura, A; Montenegro Raudales, J L; Ozaki, Y; Higuchi, K; Ukai, T; Kaneko, T; Miyazaki, T; Latz, E; Hara, Y

    2017-11-20

    Dental calculus is a mineralized deposit attached to the tooth surface. We have shown that cellular uptake of dental calculus triggers nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation, leading to the processing of the interleukin-1β precursor into its mature form in mouse and human phagocytes. The activation of the NLRP3 inflammasome also induced a lytic form of programmed cell death, pyroptosis, in these cells. However, the effects of dental calculus on other cell types in periodontal tissue have not been investigated. The aim of this study was to determine whether dental calculus can induce cell death in oral epithelial cells. HSC-2 human oral squamous carcinoma cells, HOMK107 human primary oral epithelial cells and immortalized mouse macrophages were exposed to dental calculus or 1 of its components, hydroxyapatite crystals. For inhibition assays, the cells were exposed to dental calculus in the presence or absence of cytochalasin D (endocytosis inhibitor), z-YVAD-fmk (caspase-1 inhibitor) or glyburide (NLRP3 inflammasome inhibitor). Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) release and staining with propidium iodide. Tumor necrosis factor-α production was quantified by enzyme-linked immunosorbent assay. Oral epithelial barrier function was examined by permeability assay. Dental calculus induced cell death in HSC-2 cells, as judged by LDH release and propidium iodide staining. Dental calculus also induced LDH release from HOMK107 cells. Following heat treatment, dental calculus lost its capacity to induce tumor necrosis factor-α in mouse macrophages, but could induce LDH release in HSC-2 cells, indicating a major role of inorganic components in cell death. Hydroxyapatite crystals also induced cell death in both HSC-2 and HOMK107 cells, as judged by LDH release, indicating the capacity of crystal particles to induce cell death. Cell death induced by dental

  12. Differentiation of conductive cells: a matter of life and death.

    Science.gov (United States)

    Heo, Jung-Ok; Blob, Bernhard; Helariutta, Ykä

    2017-02-01

    Two major conducting tissues in plants, phloem and xylem, are composed of highly specialized cell types adapted to long distance transport. Sieve elements (SEs) in the phloem display a thick cell wall, callose-rich sieve plates and low cytoplasmic density. SE differentiation is driven by selective autolysis combined with enucleation, after which the plasma membrane and some organelles are retained. By contrast, differentiation of xylem tracheary elements (TEs) involves complete clearance of the cellular components by programmed cell death followed by autolysis of the protoplast; this is accompanied by extensive deposition of lignin and cellulose in the cell wall. Emerging molecular data on TE and SE differentiation indicate a central role for NAC and MYB type transcription factors in both processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Functional role of kallikrein 6 in regulating immune cell survival.

    Directory of Open Access Journals (Sweden)

    Isobel A Scarisbrick

    2011-03-01

    Full Text Available Kallikrein 6 (KLK6 is a newly identified member of the kallikrein family of secreted serine proteases that prior studies indicate is elevated at sites of central nervous system (CNS inflammation and which shows regulated expression with T cell activation. Notably, KLK6 is also elevated in the serum of multiple sclerosis (MS patients however its potential roles in immune function are unknown. Herein we specifically examine whether KLK6 alters immune cell survival and the possible mechanism by which this may occur.Using murine whole splenocyte preparations and the human Jurkat T cell line we demonstrate that KLK6 robustly supports cell survival across a range of cell death paradigms. Recombinant KLK6 was shown to significantly reduce cell death under resting conditions and in response to camptothecin, dexamethasone, staurosporine and Fas-ligand. Moreover, KLK6-over expression in Jurkat T cells was shown to generate parallel pro-survival effects. In mixed splenocyte populations the vigorous immune cell survival promoting effects of KLK6 were shown to include both T and B lymphocytes, to occur with as little as 5 minutes of treatment, and to involve up regulation of the pro-survival protein B-cell lymphoma-extra large (Bcl-XL, and inhibition of the pro-apoptotic protein Bcl-2-interacting mediator of cell death (Bim. The ability of KLK6 to promote survival of splenic T cells was also shown to be absent in cell preparations derived from PAR1 deficient mice.KLK6 promotes lymphocyte survival by a mechanism that depends in part on activation of PAR1. These findings point to a novel molecular mechanism regulating lymphocyte survival that is likely to have relevance to a range of immunological responses that depend on apoptosis for immune clearance and maintenance of homeostasis.

  14. Caloric restriction suppresses apoptotic cell death in the mammalian cochlea and leads to prevention of presbycusis.

    Science.gov (United States)

    Someya, Shinichi; Yamasoba, Tatsuya; Weindruch, Richard; Prolla, Tomas A; Tanokura, Masaru

    2007-10-01

    Presbycusis is characterized by an age-related progressive decline of auditory function, and arises mainly from the degeneration of hair cells or spiral ganglion (SG) cells in the cochlea. Here we show that caloric restriction suppresses apoptotic cell death in the mouse cochlea and prevents late onset of presbycusis. Calorie restricted (CR) mice, which maintained body weight at the same level as that of young control (YC) mice, retained normal hearing and showed no cochlear degeneration. CR mice also showed a significant reduction in the number of TUNEL-positive cells and cleaved caspase-3-positive cells relative to middle-age control (MC) mice. Microarray analysis revealed that CR down-regulated the expression of 24 apoptotic genes, including Bak and Bim. Taken together, our findings suggest that loss of critical cells through apoptosis is an important mechanism of presbycusis in mammals, and that CR can retard this process by suppressing apoptosis in the inner ear tissue.

  15. Topological defects in epithelia govern cell death and extrusion

    Science.gov (United States)

    Saw, Thuan Beng; Doostmohammadi, Amin; Nier, Vincent; Kocgozlu, Leyla; Thampi, Sumesh; Toyama, Yusuke; Marcq, Philippe; Lim, Chwee Teck; Yeomans, Julia M.; Ladoux, Benoit

    2017-04-01

    Epithelial tissues (epithelia) remove excess cells through extrusion, preventing the accumulation of unnecessary or pathological cells. The extrusion process can be triggered by apoptotic signalling, oncogenic transformation and overcrowding of cells. Despite the important linkage of cell extrusion to developmental, homeostatic and pathological processes such as cancer metastasis, its underlying mechanism and connections to the intrinsic mechanics of the epithelium are largely unexplored. We approach this problem by modelling the epithelium as an active nematic liquid crystal (that has a long range directional order), and comparing numerical simulations to strain rate and stress measurements within monolayers of MDCK (Madin Darby canine kidney) cells. Here we show that apoptotic cell extrusion is provoked by singularities in cell alignments in the form of comet-shaped topological defects. We find a universal correlation between extrusion sites and positions of nematic defects in the cell orientation field in different epithelium types. The results confirm the active nematic nature of epithelia, and demonstrate that defect-induced isotropic stresses are the primary precursors of mechanotransductive responses in cells, including YAP (Yes-associated protein) transcription factor activity, caspase-3-mediated cell death, and extrusions. Importantly, the defect-driven extrusion mechanism depends on intercellular junctions, because the weakening of cell-cell interactions in an α-catenin knockdown monolayer reduces the defect size and increases both the number of defects and extrusion rates, as is also predicted by our model. We further demonstrate the ability to control extrusion hotspots by geometrically inducing defects through microcontact printing of patterned monolayers. On the basis of these results, we propose a mechanism for apoptotic cell extrusion: spontaneously formed topological defects in epithelia govern cell fate. This will be important in predicting

  16. Involvement of cytochrome c and caspases in apoptotic cell death of human submandibular gland ductal cells induced by concanamycin A.

    Science.gov (United States)

    Aiko, Katsuya; Tsujisawa, Toshiyuki; Koseki, Takeyoshi; Hashimoto, Shinichi; Morimoto, Yasuhiro; Amagasa, Teruo; Nishihara, Tatsuji

    2002-08-01

    In the present study, we found that a specific inhibitor of vacuolar type H+-ATPase (V-ATPase), concanamycin A, induced apoptosis in a human submandibular gland ductal cancer cell line, HSG. Immunoblot analysis revealed that cytochrome c was released from mitochondria into the cytoplasm when HSG cells were cultured with concanamycin A for 6 h. The maximum activities of caspase-3 and -9 were reached in HSG cells after 18 and 12 h culture of concanamycin A, respectively. Both caspase-3 and -9 were cleaved to an active form in HSG cells cultured with concanamycin A. Interestingly, concanamycin A decreased the level of heat shock protein 27 (HSP27) in HSG cells. Taken together, these findings suggest that apoptosis in HSG cells induced by concanamycin A is regulated by cytochrome c released from mitochondria into cytoplasm and the subsequent activation of caspases, and that HSP27 may interfere with caspase-dependent apoptotic cell death induced by concanamycin A.

  17. The complexity of apoptotic cell death in mollusks: An update.

    Science.gov (United States)

    Romero, A; Novoa, B; Figueras, A

    2015-09-01

    Apoptosis is a type of programmed cell death that produces changes in cell morphology and in biochemical intracellular processes without inflammatory reactions. The components of the apoptotic pathways are conserved throughout evolution. Caspases are key molecules involved in the transduction of the death signal and are responsible for many of the biochemical and morphological changes associated with apoptosis. Nowadays, It is known that caspases are activated through two major apoptotic pathways (the extrinsic or death receptor pathway and the intrinsic or mitochondrial pathway), but there are also evidences of at least other alternative pathway (the perforin/granzyme pathway). Apoptosis in mollusks seems to be similar in complexity to apoptosis in vertebrates but also has unique features maybe related to their recurrent exposure to environmental changes, pollutants, pathogens and also related to the sedentary nature of some stages in the life cycle of mollusks bivalves and gastropods. As in other animals, apoptotic process is involved in the maintenance of tissue homeostasis and also constitutes an important immune response that can be triggered by a variety of stimuli, including cytokines, hormones, toxic insults, viruses, and protozoan parasites. The main goal of this work is to present the current knowledge of the molecular mechanisms of apoptosis in mollusks and to highlight those steps that need further study. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Autophagy, programmed cell death and reactive oxygen species in sexual reproduction in plants.

    Science.gov (United States)

    Kurusu, Takamitsu; Kuchitsu, Kazuyuki

    2017-05-01

    Autophagy is one of the major cellular processes of recycling of proteins, metabolites and intracellular organelles, and plays crucial roles in the regulation of innate immunity, stress responses and programmed cell death (PCD) in many eukaryotes. It is also essential in development and sexual reproduction in many animals. In plants, although autophagy-deficient mutants of Arabidopsis thaliana show phenotypes in abiotic and biotic stress responses, their life cycle seems normal and thus little had been known until recently about the roles of autophagy in development and reproduction. Rice mutants defective in autophagy show sporophytic male sterility and immature pollens, indicating crucial roles of autophagy during pollen maturation. Enzymatic production of reactive oxygen species (ROS) by respiratory burst oxidase homologues (Rbohs) play multiple roles in regulating anther development, pollen tube elongation and fertilization. Significance of autophagy and ROS in the regulation of PCD of transient cells during plant sexual reproduction is discussed in comparison with animals.

  19. Functions of BCL-XL at the Interface between Cell Death and Metabolism

    Directory of Open Access Journals (Sweden)

    Judith Michels

    2013-01-01

    Full Text Available The BCL-2 homolog BCL-XL, one of the two protein products of BCL2L1, has originally been characterized for its prominent prosurvival functions. Similar to BCL-2, BCL-XL binds to its multidomain proapoptotic counterparts BAX and BAK, hence preventing the formation of lethal pores in the mitochondrial outer membrane, as well as to multiple BH3-only proteins, thus interrupting apical proapoptotic signals. In addition, BCL-XL has been suggested to exert cytoprotective functions by sequestering a cytosolic pool of the pro-apoptotic transcription factor p53 and by binding to the voltage-dependent anion channel 1 (VDAC1, thereby inhibiting the so-called mitochondrial permeability transition (MPT. Thus, BCL-XL appears to play a prominent role in the regulation of multiple distinct types of cell death, including apoptosis and regulated necrosis. More recently, great attention has been given to the cell death-unrelated functions of BCL-2-like proteins. In particular, BCL-XL has been shown to modulate a number of pathophysiological processes, including—but not limited to—mitochondrial ATP synthesis, protein acetylation, autophagy and mitosis. In this short review article, we will discuss the functions of BCL-XL at the interface between cell death and metabolism.

  20. Alix and ALG-2 are involved in tumor necrosis factor receptor 1-induced cell death.

    Science.gov (United States)

    Mahul-Mellier, Anne-Laure; Strappazzon, Flavie; Petiot, Anne; Chatellard-Causse, Christine; Torch, Sakina; Blot, Béatrice; Freeman, Kimberley; Kuhn, Loriane; Garin, Jérome; Verna, Jean-Marc; Fraboulet, Sandrine; Sadoul, Rémy

    2008-12-12

    Alix/AIP1 regulates cell death in a way involving interactions with the calcium-binding protein ALG-2 and with proteins of ESCRT (endosomal sorting complex required for transport). Using mass spectrometry we identified caspase-8 among proteins co-immunoprecipitating with Alix in dying neurons. We next demonstrated that Alix and ALG-2 interact with pro-caspase-8 and that Alix forms a complex with the TNFalpha receptor-1 (TNF-R1), depending on its capacity to bind ESCRT proteins. Thus, Alix and ALG-2 may allow the recruitment of pro-caspase-8 onto endosomes containing TNF-R1, a step thought to be necessary for activation of the apical caspase. In line with this, expression of Alix deleted of its ALG-2-binding site (AlixDeltaALG-2) significantly reduced TNF-R1-induced cell death, without affecting endocytosis of the receptor. In a more physiological setting, we found that programmed cell death of motoneurons, which can be inhibited by AlixDeltaALG-2, is regulated by TNF-R1. Taken together, these results highlight Alix and ALG-2 as new actors of the TNF-R1 pathway.

  1. Modulation of calcium-induced cell death in human neural stem cells by the novel peptidylarginine deiminase-AIF pathway.

    Science.gov (United States)

    U, Kin Pong; Subramanian, Venkataraman; Nicholas, Antony P; Thompson, Paul R; Ferretti, Patrizia

    2014-06-01

    PADs (peptidylarginine deiminases) are calcium-dependent enzymes that change protein-bound arginine to citrulline (citrullination/deimination) affecting protein conformation and function. PAD up-regulation following chick spinal cord injury has been linked to extensive tissue damage and loss of regenerative capability. Having found that human neural stem cells (hNSCs) expressed PAD2 and PAD3, we studied PAD function in these cells and investigated PAD3 as a potential target for neuroprotection by mimicking calcium-induced secondary injury responses. We show that PAD3, rather than PAD2 is a modulator of cell growth/death and that PAD activity is not associated with caspase-3-dependent cell death, but is required for AIF (apoptosis inducing factor)-mediated apoptosis. PAD inhibition prevents association of PAD3 with AIF and AIF cleavage required for its translocation to the nucleus. Finally, PAD inhibition also hinders calcium-induced cytoskeleton disassembly and association of PAD3 with vimentin, that we show to be associated also with AIF; together this suggests that PAD-dependent cytoskeleton disassembly may play a role in AIF translocation to the nucleus. This is the first study highlighting a role of PAD activity in balancing hNSC survival/death, identifying PAD3 as an important upstream regulator of calcium-induced apoptosis, which could be targeted to reduce neural loss, and shedding light on the mechanisms involved. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Betulinic acid induces cell death by necrosis in Trypanosoma cruzi.

    Science.gov (United States)

    Sousa, Paloma Leão; Souza, Racquel Oliveira da Silva; Tessarolo, Louise Donadello; de Menezes, Ramon Róseo Paula Pessoa Bezerra; Sampaio, Tiago Lima; Canuto, Jader Almeida; Martins, Alice Maria Costa

    2017-10-01

    Chagas' disease is a neglected disease caused by the protozoan parasite Trypanosoma cruzi and constitutes a serious health problem worldwide. The treatment is limited, with variable efficacy of benznidazole and nifurtimox. Betulinic Acid (BA), a triterpene, can be found in medicinal herbs and has a wide variety of biological and pharmacological activities. The objective was to evaluate betulinic acid effects on the cell death mechanism in Trypanosoma cruzi strain Y. BA inhibited the growth of epimastigotes in periods of 24h (IC 50 =73.43μM), 48h (IC 50 =119.8μM) and 72h (IC 50 =212.2μM) of incubation; of trypomastigotes (IC 50 =51.88μM) in periods of 24h and intracellular amastigotes (IC 50 =25.94μM) in periods of 24 and 48h of incubation, no toxicity on LLC-MK 2 cells at the concentrations used. Analysis of the possible mechanism of parasite cell death showed alterations in mitochondrial membrane potential, alterations in cell membrane integrity, an increase in the formation of reactive oxygen species and increase swelling of the reservosomes. In conclusion, betulinic acid was be able to inhibition all developmental forms of Trypanosoma cruzi Y strain with necrotic mechanism and involvement of mitochondrial membrane potential alteration and increase in reactive oxygen species. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. The Drosophila caspase DRONC is required for metamorphosis and cell death in response to irradiation and developmental signals.

    Science.gov (United States)

    Waldhuber, Markus; Emoto, Kazuo; Petritsch, Claudia

    2005-07-01

    Cell death is essential for eliminating excess cells during development as well as removing damaged cells. While multiple conserved apoptosis pathways involving different cascades of caspases, which are cysteine proteases, have been identified, their regulation in the context of a developing organism is not very well understood. Expression of the Drosophila caspase-9 homolog, DRONC, can be induced by ecdysone, a steroid hormone, which induces metamorphosis. To elucidate the functional role of DRONC during metamorphosis and for cell death during development we have generated and analyzed two loss-of-function alleles of DRONC. We report that DRONC is required for developmentally induced neuroblast cell death and apoptosis in response to X irradiation. DRONC mutants show reduced pupariation even in the presence of high levels of ecdysone and impaired cell death of larval midgut. The levels of ecdysone-inducible transcripts such as E75A and Reaper (Rpr) are normal in the absence of DRONC, suggesting that DRONC acts downstream of these genes. In addition, Reaper and Grim, but not Hid induced apoptosis is sensitive to a reduction of DRONC levels. Our study places DRONC at a central point of convergence for multiple cell death pathways and for the ecdysone pathway regulating metamorphosis.

  4. Mycobacterium tuberculosis infection induces non-apoptotic cell death of human dendritic cells

    Directory of Open Access Journals (Sweden)

    Ryan Ruth CM

    2011-10-01

    Full Text Available Abstract Background Dendritic cells (DCs connect innate and adaptive immunity, and are necessary for an efficient CD4+ and CD8+ T cell response after infection with Mycobacterium tuberculosis (Mtb. We previously described the macrophage cell death response to Mtb infection. To investigate the effect of Mtb infection on human DC viability, we infected these phagocytes with different strains of Mtb and assessed viability, as well as DNA fragmentation and caspase activity. In parallel studies, we assessed the impact of infection on DC maturation, cytokine production and bacillary survival. Results Infection of DCs with live Mtb (H37Ra or H37Rv led to cell death. This cell death proceeded in a caspase-independent manner, and without nuclear fragmentation. In fact, substrate assays demonstrated that Mtb H37Ra-induced cell death progressed without the activation of the executioner caspases, 3/7. Although the death pathway was triggered after infection, the DCs successfully underwent maturation and produced a host-protective cytokine profile. Finally, dying infected DCs were permissive for Mtb H37Ra growth. Conclusions Human DCs undergo cell death after infection with live Mtb, in a manner that does not involve executioner caspases, and results in no mycobactericidal effect. Nonetheless, the DC maturation and cytokine profile observed suggests that the infected cells can still contribute to TB immunity.

  5. Mycobacterium tuberculosis infection induces non-apoptotic cell death of human dendritic cells

    LENUS (Irish Health Repository)

    Ryan, Ruth CM

    2011-10-24

    Abstract Background Dendritic cells (DCs) connect innate and adaptive immunity, and are necessary for an efficient CD4+ and CD8+ T cell response after infection with Mycobacterium tuberculosis (Mtb). We previously described the macrophage cell death response to Mtb infection. To investigate the effect of Mtb infection on human DC viability, we infected these phagocytes with different strains of Mtb and assessed viability, as well as DNA fragmentation and caspase activity. In parallel studies, we assessed the impact of infection on DC maturation, cytokine production and bacillary survival. Results Infection of DCs with live Mtb (H37Ra or H37Rv) led to cell death. This cell death proceeded in a caspase-independent manner, and without nuclear fragmentation. In fact, substrate assays demonstrated that Mtb H37Ra-induced cell death progressed without the activation of the executioner caspases, 3\\/7. Although the death pathway was triggered after infection, the DCs successfully underwent maturation and produced a host-protective cytokine profile. Finally, dying infected DCs were permissive for Mtb H37Ra growth. Conclusions Human DCs undergo cell death after infection with live Mtb, in a manner that does not involve executioner caspases, and results in no mycobactericidal effect. Nonetheless, the DC maturation and cytokine profile observed suggests that the infected cells can still contribute to TB immunity.

  6. Misexpression of the cyclin-dependent kinase inhibitor ICK1/KRP1 in single-celled Arabidopsis trichomes reduces endoreduplication and cell size and induces cell death.

    Science.gov (United States)

    Schnittger, Arp; Weinl, Christina; Bouyer, Daniel; Schöbinger, Ulrike; Hülskamp, Martin

    2003-02-01

    A positive correlation between cell size and DNA content has been recognized in many plant cell types. Conversely, misexpression of a dominant-negative cyclin-dependent kinase (CDK) or CDK inhibitor proteins (ICK/KRPs) in Arabidopsis and tobacco leaves has revealed that cell growth can be uncoupled from cell cycle progression and DNA content. However, cell growth also appears to be controlled in a non-cell-autonomous manner by organ size, making it difficult in a ubiquitous expression assay to judge the cell-autonomous function of putative cell growth regulators. Here, we investigated the function of the CDK inhibitor ICK1/KRP1 on cell growth and differentiation independent of any compensatory influence of an organ context using Arabidopsis trichomes as a model system. By analyzing cell size with respect to DNA content, we dissected cell growth in a DNA-dependent and a DNA-independent process. We further found that ICK1/KRP1 misexpression interfered with differentiation and induced cell death, linking cell cycle progression, differentiation, and cell death in plants. The function of ICK1/KRP1 in planta was found to be dependent on a C-terminal domain and regulated negatively by an N-terminal domain. Finally, we identified CDKA;1 and a D-type cyclin as possible targets of ICK1/KRP1 expression in vivo.

  7. Inhibition of telomerase recruitment and cancer cell death.

    Science.gov (United States)

    Nakashima, Mai; Nandakumar, Jayakrishnan; Sullivan, Kelly D; Espinosa, Joaquín M; Cech, Thomas R

    2013-11-15

    Continued proliferation of human cells requires maintenance of telomere length, usually accomplished by telomerase. Telomerase is recruited to chromosome ends by interaction with a patch of amino acids (the TEL patch, for TPP1 glutamate (E) and leucine (L)-rich patch) on the surface of telomere protein TPP1. In previous studies, interruption of this interaction by mutation prevented telomere extension in HeLa cells, but the cell culture continued to grow. We now show that the telomerase inhibitor BIBR1532 acts together with TEL patch mutations to inhibit the growth of HeLa cell lines and that apoptosis is a prominent mechanism of death of these cells. Survivor cells take over the population beginning around 40 days in culture. These cells no longer express the TEL patch mutant TPP1, apparently because of silencing of the expression cassette, a survival mechanism that would not be available to cancer cells. These results provide hope that inhibiting the binding of telomerase to the TEL patch of TPP1, perhaps together with a modest inhibition of the telomerase enzyme, could comprise an effective anticancer therapy for the ∼90% of human tumors that are telomerase-positive.

  8. Akt is transferred to the nucleus of cells treated with apoptin, and it participates in apoptin-induced cell death

    DEFF Research Database (Denmark)

    Maddika, S; Bay, GH; Kroczak, TJ

    2007-01-01

    OBJECTIVES: The phosphatidylinositol 3-kinase (PI3-K)/Akt pathway is well known for the regulation of cell survival, proliferation, and some metabolic routes. MATERIALS AND METHODS: In this study, we document a novel role for the PI3-K/Akt pathway during cell death induced by apoptin, a tumour...

  9. PARP-1 and p53 Regulate the Increased Susceptibility to Oxidative Death of Lymphocytes from MCI and AD Patients.

    Science.gov (United States)

    Salech, Felipe; Ponce, Daniela P; SanMartín, Carol D; Rogers, Nicole K; Chacón, Carlos; Henríquez, Mauricio; Behrens, Maria I

    2017-01-01

    Mild cognitive impairment (MCI) is a clinically detectable initial stage of cognitive deterioration with a high conversion rate to dementia. There is increasing evidence that some of the cerebral alterations present in Alzheimer type dementia can be found in peripheral tissues. We have previously shown that lymphocytes from Alzheimer's disease (AD) patients have increased susceptibility to hydrogen peroxide (H2O2)-induced death that depends on dementia severity. We here investigated whether lymphocytes from MCI patients show increased vulnerability to death, and explored the involvement of Poly [ADP-ribose] polymerase (PARP-1) and p53 in the regulation of this process. Lymphocytes from 16 MCI and 10 AD patients, and 15 healthy controls (HCs) were submitted to increasing concentrations of H2O2 for 20 h. Cell death was determined by flow cytometry, in the presence or absence of PARP-1 inhibitors (3-aminobenzamide (3-ABA) or Nicotinamide (NAM)), or the p53 inhibitor (nutlin-3) or stabilizer (pifithrin-α). PARP-1 and p53 mRNA levels were determined by quantitative PCR (qPCR). Lymphocytes from MCI patients showed increased susceptibility to death, attaining intermediate values between AD and controls. PARP inhibitors -3-ABA and NAM- markedly protected from H2O2-induced death, making the difference between MCI and controls disappear, but not the difference between AD and controls. PARP-1 mRNA expression was increased in MCI lymphocytes. Modulation of p53 with Nutlin-3 or pifithrin-α did not modify the H2O2-induced death of lymphocytes from MCI or AD patients, but augmented the death in control lymphocytes attaining levels similar to MCI and AD. Accordingly, p53 mRNA expression was increased in AD and MCI lymphocytes compared to controls. In all, these results show that increased oxidative death is present in lymphocytes at the MCI stage. PARP-1 has a preponderant role, with complete death protection achieved with PARP inhibition in MCI lymphocytes, but not in AD

  10. Reduction of cardiac cell death after helium postconditioning in rats: transcriptional analysis of cell death and survival pathways.

    Science.gov (United States)

    Oei, Gezina T M L; Heger, Michal; van Golen, Rowan F; Alles, Lindy K; Flick, Moritz; van der Wal, Allard C; van Gulik, Thomas M; Hollmann, Markus W; Preckel, Benedikt; Weber, Nina C

    2015-01-20

    Helium, a noble gas, has been used safely in humans. In animal models of regional myocardial ischemia/reperfusion (I/R) it was shown that helium conditioning reduces infarct size. Currently, it is not known how helium exerts its cytoprotective effects and which cell death/survival pathways are affected. The objective of this study, therefore, was to investigate the cell protective effects of helium postconditioning by PCR array analysis of genes involved in necrosis, apoptosis and autophagy. Male rats were subjected to 25 min of ischemia and 5, 15 or 30 min of reperfusion. Semiquantitative histological analysis revealed that 15 min of helium postconditioning reduced the extent of I/R-induced cell damage. This effect was not observed after 5 and 30 min of helium postconditioning. Analysis of the differential expression of genes showed that 15 min of helium postconditioning mainly caused upregulation of genes involved in autophagy and inhibition of apoptosis versus I/R alone. The results suggest that the cytoprotective effects of helium inhalation may be caused by a switch from pro-cell-death signaling to activation of cell survival mechanisms, which appears to affect a wide range of pathways.

  11. Modulating cell-to-cell variability and sensitivity to death ligands by co-drugging

    Science.gov (United States)

    Flusberg, Deborah A.; Sorger, Peter K.

    2013-06-01

    TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) holds promise as an anti-cancer therapeutic but efficiently induces apoptosis in only a subset of tumor cell lines. Moreover, even in clonal populations of responsive lines, only a fraction of cells dies in response to TRAIL and individual cells exhibit cell-to-cell variability in the timing of cell death. Fractional killing in these cell populations appears to arise not from genetic differences among cells but rather from differences in gene expression states, fluctuations in protein levels and the extent to which TRAIL-induced death or survival pathways become activated. In this study, we ask how cell-to-cell variability manifests in cell types with different sensitivities to TRAIL, as well as how it changes when cells are exposed to combinations of drugs. We show that individual cells that survive treatment with TRAIL can regenerate the sensitivity and death-time distribution of the parental population, demonstrating that fractional killing is a stable property of cell populations. We also show that cell-to-cell variability in the timing and probability of apoptosis in response to treatment can be tuned using combinations of drugs that together increase apoptotic sensitivity compared to treatment with one drug alone. In the case of TRAIL, modulation of cell-to-cell variability by co-drugging appears to involve a reduction in the threshold for mitochondrial outer membrane permeabilization.

  12. HYAL-2–WWOX–SMAD4 signaling in cell death and anticancer response

    Directory of Open Access Journals (Sweden)

    Li-Jin Hsu

    2016-12-01

    Full Text Available Hyaluronidase HYAL-2 is a membrane-anchored protein and also localizes, in part, in the lysosome. Recent study from animal models revealed that both HYAL-1 and HYAL-2 are essential for the metabolism of hyaluronan (HA. Hyal-2 deficiency is associated with chronic thrombotic microangiopathy with hemolytic anemia in mice due to over accumulation of high molecular size HA. HYAL-2 is essential for platelet generation. Membrane HYAL-2 degrades HA bound by co-receptor CD44. Also, in a non-canonical signal pathway, HYAL-2 serves as a receptor for transforming growth factor beta (TGF-β to signal with downstream tumor suppressors WWOX and SMAD4 to control gene transcription. When SMAD4 responsive element is overly driven by the HYAL-2–WWOX–SMAD4 signaling complex, cell death occurs. When rats are subjected to traumatic brain injury, over accumulation of a HYAL-2–WWOX complex occurs in the nucleus to cause neuronal death. HA induces the signaling of HYAL-2–WWOX–SMAD4 and relocation of the signaling complex to the nucleus. If the signaling complex is overexpressed, bubbling cell death occurs in WWOX-expressing cells. In addition, a small synthetic peptide Zfra (zinc finger-like protein that regulates apoptosis binds membrane HYAL-2 of non-T/non-B spleen HYAL-2+ CD3- CD19- Z lymphocytes and activates the cells to generate memory anticancer response against many types of cancer cells in vivo. Whether the HYAL-2–WWOX–SMAD4 signaling complex is involved is discussed. In this review and opinion article, we have updated the current knowledge of HA, HYAL-2 and WWOX, HYAL-2–WWOX–SMAD4 signaling, bubbling cell death, and Z cell activation for memory anticancer response.

  13. Expression of the Arabidopsis high-affinity hexose transporter STP13 correlates with programmed cell death

    DEFF Research Database (Denmark)

    Nørholm, Morten Helge Hauberg; Nour-Eldin, Hussam H; Brodersen, Peter

    2006-01-01

    We report the biochemical characterization in Xenopus oocytes of the Arabidopsis thaliana membrane protein, STP13, as a high affinity, hexose-specific H(+)-symporter. Studies with kinase activators suggest that it is negatively regulated by phosphorylation. STP13 promoter GFP reporter lines show ......13 in PCD is supported by microarray data from e.g. plants undergoing senescence and a strong correlation between STP13 transcripts and the PCD phenotype in different accelerated cell death (acd11) mutants....... GFP expression only in the vascular tissue in emerging petals under non-stressed conditions. Quantitative PCR and the pSTP13-GFP plants show induction of STP13 in programmed cell death (PCD) obtained by treatments with the fungal toxin fumonisin B1 and the pathogen Pseudomonas syringae. A role for STP...

  14. From Cell Death to Metabolism: Holin-Antiholin Homologues with New Functions

    DEFF Research Database (Denmark)

    van den Esker, Marielle H.; Kovács, Ákos T.; Kuipers, Oscar P.

    2017-01-01

    Programmed cell death in bacteria is generally triggered by membrane proteins with functions analogous to those of bacteriophage holins: they disrupt the membrane potential, whereas antiholins antagonize this process. The holin-like class of proteins is present in all three domains of life......, but their functions can be different, depending on the species. Using a series of biochemical and genetic approaches, in a recent article in mBio, Charbonnier et al. (mBio 8:e00976-17, 2017, https://doi.org/10.1128/mBio.00976-17) demonstrate that the antiholin homologue in Bacillus subtilis transports pyruvate...... and is regulated in an unconventional way by its substrate molecule. Here, we discuss the connection between cell death and metabolism in various bacteria carrying genes encoding these holin-antiholin analogues and place the recent study by Charbonnier et al. in an evolutionary context....

  15. Cocaine induces cell death and activates the transcription nuclear factor kappa-B in PC12 cells.

    Science.gov (United States)

    Lepsch, Lucilia B; Munhoz, Carolina D; Kawamoto, Elisa M; Yshii, Lidia M; Lima, Larissa S; Curi-Boaventura, Maria F; Salgado, Thais M L; Curi, Rui; Planeta, Cleopatra S; Scavone, Cristoforo

    2009-02-01

    Cocaine is a worldwide used drug and its abuse is associated with physical, psychiatric and social problems. The mechanism by which cocaine causes neurological damage is very complex and involves several neurotransmitter systems. For example, cocaine increases extracellular levels of dopamine and free radicals, and modulates several transcription factors. NF-kappaB is a transcription factor that regulates gene expression involved in cellular death. Our aim was to investigate the toxicity and modulation of NF-kappaB activity by cocaine in PC 12 cells. Treatment with cocaine (1 mM) for 24 hours induced DNA fragmentation, cellular membrane rupture and reduction of mitochondrial activity. A decrease in Bcl-2 protein and mRNA levels, and an increase in caspase 3 activity and cleavage were also observed. In addition, cocaine (after 6 hours treatment) activated the p50/p65 subunit of NF-kappaB complex and the pretreatment of the cells with SCH 23390, a D1 receptor antagonist, attenuated the NF-kappaB activation. Inhibition of NF-kappaB activity by using PDTC and Sodium Salicilate increased cell death caused by cocaine. These results suggest that cocaine induces cell death (apoptosis and necrosis) and activates NF-kappaB in PC12 cells. This activation occurs, at least partially, due to activation of D1 receptors and seems to have an anti-apoptotic effect on these cells.

  16. The Combination of Alcohol and Cigarette Smoke Induces Endoplasmic Reticulum Stress and Cell Death in Pancreatic Acinar Cells.

    Science.gov (United States)

    Lugea, Aurelia; Gerloff, Andreas; Su, Hsin-Yuan; Xu, Zhihong; Go, Ariel; Hu, Cheng; French, Samuel W; Wilson, Jeremy S; Apte, Minoti V; Waldron, Richard T; Pandol, Stephen J

    2017-12-01

    Smoking, an independent risk factor for pancreatitis, accelerates the development of alcoholic pancreatitis. Alcohol feeding of mice induces up-regulation of spliced X-box binding protein 1 (XBP1s), which regulates the endoplasmic reticulum (ER) unfolded protein response and promotes cell survival upon ER stress. We examined whether smoking affects the adaptive mechanisms induced by alcohol and accelerates disorders of the ER in pancreatic acinar cells. We studied the combined effects of ethanol (EtOH) and cigarette smoke extract (CSE) on ER stress and cell death responses in mouse and human primary acini and the acinar cell line AR42J. Cells were incubated with EtOH (50 mmol/L), CSE (20-40 μg/mL), or both (CSE+EtOH), and analyzed by immunoblotting, quantitative reverse-transcription polymerase chain reaction, and cell death assays. Some cells were incubated with MKC-3946, an inhibitor of endoplasmic reticulum to nucleus signaling 1 (ERN1, also called IRE1) that blocks XBP1s formation. Male Sprague-Dawley rats were fed isocaloric amounts of an EtOH-containing (Lieber-DeCarli) or control diet for 11 weeks and exposed to cigarette smoke or room air in an exposure chamber for 2 hours each day. During the last 3 weeks, a subset of rats received intravenous injections of lipopolysaccharide (LPS, 3 mg/kg per week) to induce pancreatitis or saline (control). Pancreatic tissues were collected and analyzed by histology and immunostaining techniques. In AR42J and primary acini, CSE+EtOH induced cell death (necrosis and apoptosis), but neither agent alone had this effect. Cell death was associated with a significant decrease in expression of XBP1s. CSE+EtOH, but neither agent alone, slightly decreased adenosine triphosphate levels in AR42J cells, but induced oxidative stress and sustained activation (phosphorylation) of eukaryotic translation initiation factor 2 alpha kinase 3 (EIF2AK3, also called PERK) and increased protein levels of DNA damage inducible transcript 3 (DDIT

  17. The NRF2 Activation and Antioxidative Response Are Not Impaired Overall during Hyperoxia-Induced Lung Epithelial Cell Death

    Directory of Open Access Journals (Sweden)

    Haranatha R. Potteti

    2013-01-01

    Full Text Available Lung epithelial and endothelial cell death caused by pro-oxidant insults is a cardinal feature of acute lung injury/acute respiratory distress syndrome (ALI/ARDS patients. The NF-E2-related factor 2 (NRF2 activation in response to oxidant exposure is crucial to the induction of several antioxidative and cytoprotective enzymes that mitigate cellular stress. Since prolonged exposure to hyperoxia causes cell death, we hypothesized that chronic hyperoxia impairs NRF2 activation, resulting in cell death. To test this hypothesis, we exposed nonmalignant small airway epithelial cells (AECs to acute (1–12 h and chronic (36–48 h hyperoxia and evaluated cell death, NRF2 nuclear accumulation and target gene expression, and NRF2 recruitment to the endogenous HMOX1 and NQO1 promoters. As expected, hyperoxia gradually induced death in AECs, noticeably and significantly by 36 h; ~60% of cells were dead by 48 h. However, we unexpectedly found increased expression levels of NRF2-regulated antioxidative genes and nuclear NRF2 in AECs exposed to chronic hyperoxia as compared to acute hyperoxia. Chromatin Immunoprecipitation (ChIP assays revealed an increased recruitment of NRF2 to the endogenous HMOX1 and NQO1 promoters in AECs exposed to acute or chronic hyperoxia. Thus, our findings demonstrate that NRF2 activation and antioxidant gene expression are functional during hyperoxia-induced lung epithelial cell death and that chronic hyperoxia does not impair NRF2 signaling overall.

  18. Clozapine Induces Autophagic Cell Death in Non-Small Cell Lung Cancer Cells

    Directory of Open Access Journals (Sweden)

    Yu-Chun Yin

    2015-02-01

    Full Text Available Background/Aims: Previous studies have shown that patients with schizophrenia have a lower incidence of cancer than the general population, and several antipsychotics have been demonstrated to have cytotoxic effects on cancer cells. However, the mechanisms underlying these results remain unclear. The present study aimed to investigate the effect of clozapine, which is often used to treat patients with refractory schizophrenia, on the growth of non-small cell lung carcinoma cell lines and to examine whether autophagy contributes to its effects. Methods: A549 and H1299 cells were treated with clozapine, and cell cytotoxicity, cell cycle and autophagy were then assessed. The autophagy inhibitor bafilomycin A1 and siRNA-targeted Atg7 were used to determine the role of autophagy in the effect of clozapine. Results: Clozapine inhibited A549 and H1299 proliferation and increased p21 and p27 expression levels, leading to cell cycle arrest. Clozapine also induced a high level of autophagy, but not apoptosis, in both cell lines, and the growth inhibitory effect of clozapine was blunted by treatment with the autophagy inhibitor bafilomycin A1 or with an siRNA targeting atg7. Conclusions: Clozapine inhibits cell proliferation by inducing autophagic cell death in two non-small cell lung carcinoma cell lines. These findings may provide insights into the relationship between clozapine use and the lower incidence of lung cancer among patients with schizophrenia.

  19. Inhibition by anandamide of 6-hydroxydopamine-induced cell death in PC12 cells.

    LENUS (Irish Health Repository)

    Mnich, Katarzyna

    2010-01-01

    6-hydroxydopamine (6-OHDA) is a selective neurotoxin that is widely used to investigate cell death and protective strategies in models of Parkinson\\'s disease. Here, we investigated the effects of the endogenous cannabinoid, anandamide, on 6-OHDA-induced toxicity in rat adrenal phaeochromocytoma PC12 cells. Morphological analysis and caspase-3 activity assay revealed that anandamide inhibited 6-OHDA-induced apoptosis. The protection was not affected by antagonists of either cannabinoid receptors (CB(1) or CB(2)) or the vanilloid receptor TRPV1. Anandamide-dependent protection was reduced by pretreatment with LY294002 (inhibitor of phosphatidylinositol 3-kinase, PI3K) and unaffected by U0126 (inhibitor of extracellularly-regulated kinase). Interestingly, phosphorylation of c-Jun-NH2-terminal kinase (JNK) in cells exposed to 6-OHDA was strongly reduced by anandamide pre-treatment. Furthermore, 6-OHDA induced c-Jun activation and increased Bim expression, both of which were inhibited by anandamide. Together, these data demonstrate antiapoptotic effects of anandamide and also suggest a role for activation of PI3K and inhibition of JNK signalling in anandamide-mediated protection against 6-OHDA.

  20. GAS1 induces cell death through an intrinsic apoptotic pathway.

    Science.gov (United States)

    Zarco, Natanael; González-Ramírez, Ricardo; González, Rosa O; Segovia, José

    2012-06-01

    Growth Arrest Specific 1 (GAS1) is a protein expressed when cells are arrested and during development. When ectopically expressed, GAS1 induces cell arrest and apoptosis of different cell lines, and we have previously demonstrated that the apoptotic process set off by GAS1 is caused by its capacity inhibiting the GDNF-mediated intracellular survival signaling. In the present work, we have dissected the molecular pathway leading to cell death. We employed the SH-SY5Y human neuroblastoma cell line that expresses GAS1 when deprived of serum. We observed, as we have previously described, that the presence of GAS1 reduces RET phosphorylation and inhibits the activation of AKT. We have now determined that the presence of GAS1 also triggers the dephosphorylation of BAD, which, in turn, provokes the release of Cytochrome-c from the mitochondria to the cytosol activating caspase-9, prompting the activity of caspase-3 and resulting in apoptosis of the cells. The apoptotic process is intrinsic, because there is no activation of caspase-8, thus this is consistent with apoptosis induced by the lack of trophic support. Interestingly, in cells where GAS1 has been silenced there is a significant delay in the onset of apoptosis.

  1. Anhydrobiosis and programmed cell death in plants: Commonalities and Differences

    Directory of Open Access Journals (Sweden)

    Samer Singh

    2015-05-01

    Full Text Available Anhydrobiosis is an adaptive strategy of certain organisms or specialised propagules to survive in the absence of water while programmed cell death (PCD is a finely tuned cellular process of the selective elimination of targeted cell during developmental programme and perturbed biotic and abiotic conditions. Particularly during water stress both the strategies serve single purpose i.e., survival indicating PCD may also function as an adaptive process under certain conditions. During stress conditions PCD cause targeted cells death in order to keep the homeostatic balance required for the organism survival, whereas anhydrobiosis suspends cellular metabolic functions mimicking a state similar to death until reestablishment of the favourable conditions. Anhydrobiosis is commonly observed among organisms that have ability to revive their metabolism on rehydration after removal of all or almost all cellular water without damage. This feature is widely represented in terrestrial cyanobacteria and bryophytes where it is very common in both vegetative and reproductive stages of life-cycle. In the course of evolution, with the development of advanced vascular system in higher plants, anhydrobiosis was gradually lost from the vegetative phase of life-cycle. Though it is retained in resurrection plants that primarily belong to thallophytes and a small group of vascular angiosperm, it can be mostly found restricted in orthodox seeds of higher plants. On the contrary, PCD is a common process in all eukaryotes from unicellular to multicellular organisms including higher plants and mammals. In this review we discuss physiological and biochemical commonalities and differences between anhydrobiosis and PCD.

  2. Diel in situ picophytoplankton cell death cycles coupled with cell division

    NARCIS (Netherlands)

    Llabres, M.; Agustí, S.; Herndl, G.J.

    2011-01-01

    The diel variability in picophytoplankton cell death was analyzed by quantifying the proportion of dead cyanobacteria Prochlorococcus and Synechococcus cells along several in situ diel cycles in the open Mediterranean Sea. During the diel cycle, total cell abundance varied on average 2.8 +/- 0.6 and

  3. Caspase-2-dependent dendritic cell death, maturation, and priming of T cells in response to Brucella abortus infection.

    Directory of Open Access Journals (Sweden)

    Xinna Li

    Full Text Available Smooth virulent Brucella abortus strain 2308 (S2308 causes zoonotic brucellosis in cattle and humans. Rough B. abortus strain RB51, derived from S2308, is a live attenuated cattle vaccine strain licensed in the USA and many other countries. Our previous report indicated that RB51, but not S2308, induces a caspase-2-dependent apoptotic and necrotic macrophage cell death. Dendritic cells (DCs are professional antigen presenting cells critical for bridging innate and adaptive immune responses. In contrast to Brucella-infected macrophages, here we report that S2308 induced higher levels of apoptotic and necrotic cell death in wild type bone marrow-derived DCs (WT BMDCs than RB51. The RB51 and S2308-induced BMDC cell death was regulated by caspase-2, indicated by the minimal cell death in RB51 and S2308-infected BMDCs isolated from caspase-2 knockout mice (Casp2KO BMDCs. More S2308 bacteria were taken up by Casp2KO BMDCs than wild type BMDCs. Higher levels of S2308 and RB51 cells were found in infected Casp2KO BMDCs compared to infected WT BMDCs at different time points. RB51-infected wild type BMDCs were mature and activated as shown by significantly up-regulated expression of CD40, CD80, CD86, MHC-I, and MHC-II. RB51 induced the production of cytokines TNF-α, IL-6, IFN-γ and IL12/IL23p40 in infected BMDCs. RB51-infected WT BMDCs also stimulated the proliferation of CD4(+ and CD8(+ T cells compared to uninfected WT BMDCs. However, the maturation, activation, and cytokine secretion are significantly impaired in Casp2KO BMDCs infected with RB51 or Salmonella (control. S2308-infected WT and Casp2KO BMDCs were not activated and could not induce cytokine production. These results demonstrated that virulent smooth strain S2308 induced more apoptotic and necrotic dendritic cell death than live attenuated rough vaccine strain RB51; however, RB51, but not its parent strain S2308, induced caspase-2-mediated DC maturation, cytokine production, antigen

  4. Caspase-2-dependent dendritic cell death, maturation, and priming of T cells in response to Brucella abortus infection.

    Science.gov (United States)

    Li, Xinna; He, Yongqun

    2012-01-01

    Smooth virulent Brucella abortus strain 2308 (S2308) causes zoonotic brucellosis in cattle and humans. Rough B. abortus strain RB51, derived from S2308, is a live attenuated cattle vaccine strain licensed in the USA and many other countries. Our previous report indicated that RB51, but not S2308, induces a caspase-2-dependent apoptotic and necrotic macrophage cell death. Dendritic cells (DCs) are professional antigen presenting cells critical for bridging innate and adaptive immune responses. In contrast to Brucella-infected macrophages, here we report that S2308 induced higher levels of apoptotic and necrotic cell death in wild type bone marrow-derived DCs (WT BMDCs) than RB51. The RB51 and S2308-induced BMDC cell death was regulated by caspase-2, indicated by the minimal cell death in RB51 and S2308-infected BMDCs isolated from caspase-2 knockout mice (Casp2KO BMDCs). More S2308 bacteria were taken up by Casp2KO BMDCs than wild type BMDCs. Higher levels of S2308 and RB51 cells were found in infected Casp2KO BMDCs compared to infected WT BMDCs at different time points. RB51-infected wild type BMDCs were mature and activated as shown by significantly up-regulated expression of CD40, CD80, CD86, MHC-I, and MHC-II. RB51 induced the production of cytokines TNF-α, IL-6, IFN-γ and IL12/IL23p40 in infected BMDCs. RB51-infected WT BMDCs also stimulated the proliferation of CD4(+) and CD8(+) T cells compared to uninfected WT BMDCs. However, the maturation, activation, and cytokine secretion are significantly impaired in Casp2KO BMDCs infected with RB51 or Salmonella (control). S2308-infected WT and Casp2KO BMDCs were not activated and could not induce cytokine production. These results demonstrated that virulent smooth strain S2308 induced more apoptotic and necrotic dendritic cell death than live attenuated rough vaccine strain RB51; however, RB51, but not its parent strain S2308, induced caspase-2-mediated DC maturation, cytokine production, antigen presentation, and T

  5. Inhibition of never in mitosis A (NIMA)-related kinase-4 reduces survivin expression and sensitizes cancer cells to TRAIL-induced cell death.

    Science.gov (United States)

    Park, So Jung; Jo, Doo Sin; Jo, Se-Young; Shin, Dong Woon; Shim, Sangmi; Jo, Yoon Kyung; Shin, Ji Hyun; Ha, Ye Jin; Jeong, Seong-Yun; Hwang, Jung Jin; Kim, Young Sam; Suh, Young-Ah; Chang, Jong Wook; Kim, Jin Cheon; Cho, Dong-Hyung

    2016-10-04

    The tumor necrosis factor-related apoptosis inducing ligand (TRAIL) preferentially induces apoptosis in cancer cells. However, many tumors are resistant to TRAIL-induced apoptosis, and resistance mechanisms are not fully understood. To identify novel regulatory molecules of TRAIL resistance, we screened a siRNA library targeting the human kinome, and NEK4 (NIMA-related kinase-4) was identified. Knockdown of NEK4 sensitized TRAIL-resistant cancer cells and in vivo xenografts to cell death. In contrast, over expression of NEK4 suppressed TRAIL-induced cell death in TRAIL-sensitive cancer cells. In addition, loss of NEK4 resulted in decrease of the anti-apoptotic protein survivin, but an increase in apoptotic cell death. Interestingly, NEK4 was highly upregulated in tumor tissues derived from patients with lung cancer and colon cancer. These results suggest that inhibition of NEK4 sensitizes cancer cells to TRAIL-induced apoptosis by regulation of survivin expression.

  6. Thy28 protects against anti-CD3-mediated thymic cell death in vivo.

    Science.gov (United States)

    Toyota, H; Sudo, K; Kojima, K; Yanase, N; Nagao, T; Takahashi, R H; Iobe, H; Kuwabara, T; Kakiuchi, T; Mizuguchi, J

    2015-04-01

    Apoptotic cell death plays a pivotal role in the development and/or maintenance of several tissues including thymus. Deregulated thymic cell death is associated with autoimmune diseases including experimental autoimmune encephalomyelitis (EAE), a prototype murine model for analysis of human multiple sclerosis. Because Thy28 expression is modulated during thymocyte development, we tested whether Thy28 affects induction of EAE as effectively as antigen-induced thymocyte deletion using Thy28 transgenic (TG) mice. Thy28 TG mice showed partial resistance to anti-CD3 monoclonal antibody (mAb)-induced thymic cell death in vivo, as assessed by annexin V-expression and loss of mitochondrial membrane potential. The resistance to anti-CD3 mAb-induced cell death in Thy28 TG mice appeared to correlate with a decreased c-Jun N-terminal kinase phosphorylation and reduced down-regulation of Bcl-xL. Moreover, thymic hyperplasia was detected in Thy28 TG mice, although thymocyte development was unaltered. Development of peripheral lymphoid tissues including spleen and lymph nodes was also unaltered. Thy28 TG spleen T cells showed an increased production of IFN-γ, but not IL-17, in response to both anti-CD3 and anti-CD28 mAbs. Finally, Thy28 TG mice displayed accelerated induction of EAE as assessed by disease incidence, clinical score, and pathology following immunization with myelin oligodendrocyte glycoprotein compared with control WT mice. These findings suggest that modulation of Thy28 expression plays a crucial role in the determination of thymic cell fate, which may contribute to the development of EAE through proinflammatory cytokine production.

  7. Programmed Cell Death in Procyclic Form Trypanosoma brucei rhodesiense - Identification of Differentially Expressed Genes during Con A Induced Death

    Directory of Open Access Journals (Sweden)

    Welburn Susan C

    1999-01-01

    Full Text Available Trypanosoma brucei rhodesiense can be induced to undergo apoptosis after stimulation with Con A. As cell death in these parasites is associated with de novo gene expression we have applied a differential display technique, Randomly Amplified Differential Expressed Sequence-Polymerase Chain Reaction (RADES-PCR to the study of gene expression during Con A induced cell death in these organisms. Twenty-two differentially displayed products have been cloned and sequenced. These represent the first endogenous genes to be identified as implicated in cellular death in trypanosomatids (the most primitive eukaryote in which apoptosis has been described. Evidence for an ancestral death machinery, `proto-apoptosis' in single celled organisms is discussed.

  8. Attenuation of oxidative neuronal cell death by coffee phenolic phytochemicals

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Eun Sun; Jang, Young Jin [Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921 (Korea, Republic of); Hwang, Mun Kyung; Kang, Nam Joo [Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921 (Korea, Republic of); Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea, Republic of); Lee, Ki Won [Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea, Republic of)], E-mail: kiwon@konkuk.ac.kr; Lee, Hyong Joo [Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921 (Korea, Republic of)], E-mail: leehyjo@snu.ac.kr

    2009-02-10

    Neurodegenerative disorders such as Alzheimer's disease (AD) are strongly associated with oxidative stress, which is induced by reactive oxygen species (ROS) including hydrogen peroxide (H{sub 2}O{sub 2}). Recent studies suggest that moderate coffee consumption may reduce the risk of neurodegenerative diseases such as AD, but the molecular mechanisms underlying this effect remain to be clarified. In this study, we investigated the protective effects of chlorogenic acid (5-O-caffeoylquinic acid; CGA), a major phenolic phytochemical found in instant decaffeinated coffee (IDC), and IDC against oxidative PC12 neuronal cell death. IDC (1 and 5 {mu}g/ml) or CGA (1 and 5 {mu}M) attenuated H{sub 2}O{sub 2}-induced PC12 cell death. H{sub 2}O{sub 2}-induced nuclear condensation and DNA fragmentation were strongly inhibited by pretreatment with IDC or CGA. Pretreatment with IDC or CGA also inhibited the H{sub 2}O{sub 2}-induced cleavage of poly(ADP-ribose) polymerase (PARP), and downregulation of Bcl-X{sub L} and caspase-3. The accumulation of intracellular ROS in H{sub 2}O{sub 2}-treated PC12 cells was dose-dependently diminished by IDC or CGA. The activation of c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) by H{sub 2}O{sub 2} in PC12 cells was also inhibited by IDC or CGA. Collectively, these results indicate that IDC and CGA protect PC12 cells from H{sub 2}O{sub 2}-induced apoptosis by blocking the accumulation of intracellular ROS and the activation of MAPKs.

  9. Staurosporine induces necroptotic cell death under caspase-compromised conditions in U937 cells.

    Directory of Open Access Journals (Sweden)

    Zsuzsanna A Dunai

    Full Text Available For a long time necrosis was thought to be an uncontrolled process but evidences recently have revealed that necrosis can also occur in a regulated manner. Necroptosis, a type of programmed necrosis is defined as a death receptor-initiated process under caspase-compromised conditions. The process requires the kinase activity of receptor-interacting protein kinase 1 and 3 (RIPK1 and RIPK3 and mixed lineage kinase domain-like protein (MLKL, as a substrate of RIPK3. The further downstream events remain elusive. We applied known inhibitors to characterize the contributing enzymes in necroptosis and their effect on cell viability and different cellular functions were detected mainly by flow cytometry. Here we report that staurosporine, the classical inducer of intrinsic apoptotic pathway can induce necroptosis under caspase-compromised conditions in U937 cell line. This process could be hampered at least partially by the RIPK1 inhibitor necrotstin-1 and by the heat shock protein 90 kDa inhibitor geldanamycin. Moreover both the staurosporine-triggered and the classical death ligand-induced necroptotic pathway can be effectively arrested by a lysosomal enzyme inhibitor CA-074-OMe and the recently discovered MLKL inhibitor necrosulfonamide. We also confirmed that the enzymatic role of poly(ADP-ribosepolymerase (PARP is dispensable in necroptosis but it contributes to membrane disruption in secondary necrosis. In conclusion, we identified a novel way of necroptosis induction that can facilitate our understanding of the molecular mechanisms of necroptosis. Our results shed light on alternative application of staurosporine, as a possible anticancer therapeutic agent. Furthermore, we showed that the CA-074-OMe has a target in the signaling pathway leading to necroptosis. Finally, we could differentiate necroptotic and secondary necrotic processes based on participation of PARP enzyme.

  10. Cyclosporine A induces apoptotic and autophagic cell death in rat pituitary GH3 cells.

    Science.gov (United States)

    Kim, Han Sung; Choi, Seung-Il; Jeung, Eui-Bae; Yoo, Yeong-Min

    2014-01-01

    Cyclosporine A (CsA) is a powerful immunosuppressive drug with side effects including the development of chronic nephrotoxicity. In this study, we investigated CsA treatment induced apoptotic and autophagic cell death in pituitary GH3 cells. CsA treatment (0.1 to 10 µM) decreased survival of GH3 cells in a dose-dependent manner. Cell viability decreased significantly with increasing CsA concentrations largely due to an increase in apoptosis, while cell death rates due to autophagy altered only slightly. Several molecular and morphological features correlated with cell death through these distinct pathways. At concentrations ranging from 1.0 to 10 µM, CsA induced a dose-dependent increase in expression of the autophagy markers LC3-I and LC3-II. Immunofluorescence staining revealed markedly increased levels of both LC3 and lysosomal-associated membrane protein 2 (Lamp2), indicating increases in autophagosomes. At the same CsA doses, apoptotic cell death was apparent as indicated by nuclear and DNA fragmentation and increased p53 expression. In apoptotic or autophagic cells, p-ERK levels were highest at 1.0 µM CsA compared to control or other doses. In contrast, Bax levels in both types of cell death were increased in a dose-dependent manner, while Bcl-2 levels showed dose-dependent augmentation in autophagy and were decreased in apoptosis. Manganese superoxide dismutase (Mn-SOD) showed a similar dose-dependent reduction in cells undergoing apoptosis, while levels of the intracellular calcium ion exchange maker calbindin-D9k were decreased in apoptosis (1.0 to 5 µM CsA), but unchanged in autophagy. In conclusion, these results suggest that CsA induction of apoptotic or autophagic cell death in rat pituitary GH3 cells depends on the relative expression of factors and correlates with Bcl-2 and Mn-SOD levels.

  11. Early death during chemotherapy in patients with small-cell lung cancer

    DEFF Research Database (Denmark)

    Lassen, U N; Osterlind, K; Hirsch, F R

    1999-01-01

    Based on an increased frequency of early death (death within the first treatment cycle) in our two latest randomized trials of combination chemotherapy in small-cell lung cancer (SCLC), we wanted to identify patients at risk of early non-toxic death (ENTD) and early toxic death (ETD). Data were...

  12. How Heme Oxygenase-1 Prevents Heme-Induced Cell Death.

    Directory of Open Access Journals (Sweden)

    Lilibeth Lanceta

    Full Text Available Earlier observations indicate that free heme is selectively toxic to cells lacking heme oxygenase-1 (HO-1 but how this enzyme prevents heme toxicity remains unexplained. Here, using A549 (human lung cancer and immortalized human bronchial epithelial cells incubated with exogenous heme, we find knock-down of HO-1 using siRNA does promote the accumulation of cell-associated heme and heme-induced cell death. However, it appears that the toxic effects of heme are exerted by "loose" (probably intralysosomal iron because cytotoxic effects of heme are lessened by pre-incubation of HO-1 deficient cells with desferrioxamine (which localizes preferentially in the lysosomal compartment. Desferrioxamine also decreases lysosomal rupture promoted by intracellularly generated hydrogen peroxide. Supporting the importance of endogenous oxidant production, both chemical and siRNA inhibition of catalase activity predisposes HO-1 deficient cells to heme-mediated killing. Importantly, it appears that HO-1 deficiency somehow blocks the induction of ferritin; control cells exposed to heme show ~10-fold increases in ferritin heavy chain expression whereas in heme-exposed HO-1 deficient cells ferritin expression is unchanged. Finally, overexpression of ferritin H chain in HO-1 deficient cells completely prevents heme-induced cytotoxicity. Although two other products of HO-1 activity--CO and bilirubin--have been invoked to explain HO-1-mediated cytoprotection, we conclude that, at least in this experimental system, HO-1 activity triggers the induction of ferritin and the latter is actually responsible for the cytoprotective effects of HO-1 activity.

  13. Mitochondrial peroxiredoxin 3 regulates sensory cell survival in the cochlea.

    Directory of Open Access Journals (Sweden)

    Fu-Quan Chen

    Full Text Available This study delineates the role of peroxiredoxin 3 (Prx3 in hair cell death induced by several etiologies of acquired hearing loss (noise trauma, aminoglycoside treatment, age. In vivo, Prx3 transiently increased in mouse cochlear hair cells after traumatic noise exposure, kanamycin treatment, or with progressing age before any cell loss occurred; when Prx3 declined, hair cell loss began. Maintenance of high Prx3 levels via treatment with the radical scavenger 2,3-dihydroxybenzoate prevented kanamycin-induced hair cell death. Conversely, reducing Prx3 levels with Prx3 siRNA increased the severity of noise-induced trauma. In mouse organ of Corti explants, reactive oxygen species and levels of Prx3 mRNA and protein increased concomitantly at early times of drug challenge. When Prx3 levels declined after prolonged treatment, hair cells began to die. The radical scavenger p-phenylenediamine maintained Prx3 levels and attenuated gentamicin-induced hair cell death. Our results suggest that Prx3 is up-regulated in response to oxidative stress and that maintenance of Prx3 levels in hair cells is a critical factor in their susceptibility to acquired hearing loss.

  14. The endocannabinoid N-arachidonoyl dopamine (NADA) selectively induces oxidative stress-mediated cell death in hepatic stellate cells but not in hepatocytes.

    Science.gov (United States)

    Wojtalla, Alexandra; Herweck, Frank; Granzow, Michaela; Klein, Sabine; Trebicka, Jonel; Huss, Sebastian; Lerner, Raissa; Lutz, Beat; Schildberg, Frank Alexander; Knolle, Percy Alexander; Sauerbruch, Tilman; Singer, Manfred Vincenz; Zimmer, Andreas; Siegmund, Sören Volker

    2012-04-15

    The endocannabinoid system is a crucial regulator of hepatic fibrogenesis. We have previously shown that the endocannabinoid anandamide (AEA) is a lipid mediator that blocks proliferation and induces death in hepatic stellate cells (HSCs), the main fibrogenic cell type in the liver, but not in hepatocytes. However, the effects of other endocannabinoids such as N-arachidonoyl dopamine (NADA) have not yet been investigated. The NADA-synthesizing enzyme tyrosine hydroxylase was mainly expressed in sympathetic neurons in portal tracts. Its expression pattern stayed unchanged in normal or fibrotic liver. NADA dose dependently induced cell death in culture-activated primary murine or human HSCs after 2-4 h, starting from 5 μM. Despite caspase 3 cleavage, NADA-mediated cell death showed typical features of necrosis, including ATP depletion. Although the cannabinoid receptors CB1, CB2, or transient receptor potential cation channel subfamily V, member 1 were expressed in HSCs, their pharmacological or genetic blockade failed to inhibit NADA-mediated death, indicating a cannabinoid-receptor-independent mechanism. Interestingly, membrane cholesterol depletion with methyl-β-cyclodextrin inhibited AEA- but not NADA-induced death. NADA significantly induced reactive oxygen species formation in HSCs. The antioxidant glutathione (GSH) significantly decreased NADA-induced cell death. Similar to AEA, primary hepatocytes were highly resistant against NADA-induced death. Resistance to NADA in hepatocytes was due to high levels of GSH, since GSH depletion significantly increased NADA-induced death. Moreover, high expression of the AEA-degrading enzyme fatty acid amide hydrolase (FAAH) in hepatocytes also conferred resistance towards NADA-induced death, since pharmacological or genetic FAAH inhibition significantly augmented hepatocyte death. Thus the selective induction of cell death in HSCs proposes NADA as a novel antifibrogenic mediator.

  15. Death by over-eating: The Gaucher disease associated gene GBA1, identified in a screen for mediators of autophagic cell death, is necessary for developmental cell death in Drosophila midgut

    Science.gov (United States)

    Schejter, Eyal; Bialik, Shani; Levin-Zaidman, Smadar; Kimchi, Adi

    2017-01-01

    ABSTRACT Autophagy is critical for homeostasis and cell survival during stress, but can also lead to cell death, a little understood process that has been shown to contribute to developmental cell death in lower model organisms, and to human cancer cell death. We recently reported1 on our thorough molecular and morphologic characterization of an autophagic cell death system involving resveratrol treatment of lung carcinoma cells. To gain mechanistic insight into this death program, we performed a signalome-wide RNAi screen for genes whose functions are necessary for resveratrol-induced death. The screen identified GBA1, the gene encoding the lysosomal enzyme glucocerebrosidase, as an important mediator of autophagic cell death. Here we further show the physiological relevance of GBA1 to developmental cell death in midgut regression during Drosophila metamorphosis. We observed a delay in midgut cell death in two independent Gba1a RNAi lines, indicating the critical importance of Gba1a for midgut development. Interestingly, loss-of-function GBA1 mutations lead to Gaucher Disease and are a significant risk factor for Parkinson Disease, which have been associated with defective autophagy. Thus GBA1 is a conserved element critical for maintaining proper levels of autophagy, with high levels leading to autophagic cell death. PMID:28933588

  16. Steroid-triggered, cell-autonomous death of a Drosophila motoneuron during metamorphosis.

    Science.gov (United States)

    Winbush, Ari; Weeks, Janis C

    2011-04-27

    The metamorphosis of Drosophila melanogaster is accompanied by elimination of obsolete neurons via programmed cell death (PCD). Metamorphosis is regulated by ecdysteroids, including 20-hydroxyecdysone (20E), but the roles and modes of action of hormones in regulating neuronal PCD are incompletely understood. We used targeted expression of GFP to track the fate of a larval motoneuron, RP2, in ventral ganglia. RP2s in abdominal neuromeres two through seven (A2 to A7) exhibited fragmented DNA by 15 hours after puparium formation (h-APF) and were missing by 20 h-APF. RP2 death began shortly after the 'prepupal pulse' of ecdysteroids, during which time RP2s expressed ecdysteroid receptors (EcRs). Genetic manipulations showed that RP2 death required the function of EcR-B isoforms, the death-activating gene, reaper (but not hid), and the apoptosome component, Dark. PCD was blocked by expression of the caspase inhibitor p35 but unaffected by manipulating Diap1. In contrast, aCC motoneurons in neuromeres A2 to A7, and RP2s in neuromere A1, expressed EcRs during the prepupal pulse but survived into the pupal stage under all conditions tested. To test the hypothesis that ecdysteroids trigger RP2's death directly, we placed abdominal GFP-expressing neurons in cell culture immediately prior to the prepupal pulse, with or without 20E. 20E induced significant PCD in putative RP2s, but not in control neurons, as assessed by morphological criteria and propidium iodide staining. These findings suggest that the rise of ecdysteroids during the prepupal pulse acts directly, via EcR-B isoforms, to activate PCD in RP2 motoneurons in abdominal neuromeres A2 to A7, while sparing RP2s in A1. Genetic manipulations suggest that RP2's death requires Reaper function, apoptosome assembly and Diap1-independent caspase activation. RP2s offer a valuable 'single cell' approach to the molecular understanding of neuronal death during insect metamorphosis and, potentially, of neurodegeneration in other

  17. Steroid-triggered, cell-autonomous death of a Drosophila motoneuron during metamorphosis

    Directory of Open Access Journals (Sweden)

    Winbush Ari

    2011-04-01

    Full Text Available Abstract Background The metamorphosis of Drosophila melanogaster is accompanied by elimination of obsolete neurons via programmed cell death (PCD. Metamorphosis is regulated by ecdysteroids, including 20-hydroxyecdysone (20E, but the roles and modes of action of hormones in regulating neuronal PCD are incompletely understood. Results We used targeted expression of GFP to track the fate of a larval motoneuron, RP2, in ventral ganglia. RP2s in abdominal neuromeres two through seven (A2 to A7 exhibited fragmented DNA by 15 hours after puparium formation (h-APF and were missing by 20 h-APF. RP2 death began shortly after the 'prepupal pulse' of ecdysteroids, during which time RP2s expressed ecdysteroid receptors (EcRs. Genetic manipulations showed that RP2 death required the function of EcR-B isoforms, the death-activating gene, reaper (but not hid, and the apoptosome component, Dark. PCD was blocked by expression of the caspase inhibitor p35 but unaffected by manipulating Diap1. In contrast, aCC motoneurons in neuromeres A2 to A7, and RP2s in neuromere A1, expressed EcRs during the prepupal pulse but survived into the pupal stage under all conditions tested. To test the hypothesis that ecdysteroids trigger RP2's death directly, we placed abdominal GFP-expressing neurons in cell culture immediately prior to the prepupal pulse, with or without 20E. 20E induced significant PCD in putative RP2s, but not in control neurons, as assessed by morphological criteria and propidium iodide staining. Conclusions These findings suggest that the rise of ecdysteroids during the prepupal pulse acts directly, via EcR-B isoforms, to activate PCD in RP2 motoneurons in abdominal neuromeres A2 to A7, while sparing RP2s in A1. Genetic manipulations suggest that RP2's death requires Reaper function, apoptosome assembly and Diap1-independent caspase activation. RP2s offer a valuable 'single cell' approach to the molecular understanding of neuronal death during insect

  18. Programmed cell death-1 is expressed in large retinal ganglion cells and is upregulated after optic nerve crush.

    Science.gov (United States)

    Wang, Wei; Chan, Ann; Qin, Yu; Kwong, Jacky M K; Caprioli, Joseph; Levinson, Ralph; Chen, Ling; Gordon, Lynn K

    2015-11-01

    Programmed cell death-1 (PD-1) is a key negative receptor inducibly expressed on T cells, B cells and dendritic cells. It was discovered on T cells undergoing classical programmed cell death. Studies showed that PD-1 ligation promotes retinal ganglion cell (RGC) death during retinal development. The purpose of this present study is to characterize PD-1 regulation in the retina after optic nerve crush (ONC). C57BL/6 mice were subjected to ONC and RGC loss was monitored by immunolabelling with RNA-binding protein with multiple splicing (Rbpms). Time course of PD-1 mRNA expression was determined by real-time PCR. PD-1 expression was detected with anti-PD-1 antibody on whole mount retinas. PD-1 staining intensity was quantitated. Colocalization of PD-1 and cleaved-caspase-3 after ONC was analyzed. Real-time PCR results demonstrated that PD-1 gene expression was significantly upregulated at day 1, 3, 7, 10 and 14 after ONC. Immunofluorescent staining revealed a dramatic increase of PD-1 expression following ONC. In both control and injured retinas, PD-1 tended to be up-expressed in a subtype of RGCs, whose somata size were significantly larger than others. Compared to control, PD-1 intensity in large RGCs was increased by 82% in the injured retina. None of the large RGCs expressed cleaved-caspase-3 at day 5 after ONC. Our work presents the first evidence of PD-1 induction in RGCs after ONC. This observation supports further investigation into the role of PD-1 expression during RGC death or survival following injury. Published by Elsevier Ltd.

  19. A receptor tyrosine kinase inhibitor, Tyrphostin A9 induces cancer cell death through Drp1 dependent mitochondria fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Park, So Jung; Park, Young Jun; Shin, Ji Hyun; Kim, Eun Sung [Graduate School of East-West Medical Science, Kyung Hee University, Gyeoggi-Do 446-701 (Korea, Republic of); Hwang, Jung Jin; Jin, Dong-Hoon; Kim, Jin Cheon [Institute for Innovative Cancer Research, Asan Medical Center, Seoul 138-736 (Korea, Republic of); Cho, Dong-Hyung, E-mail: dhcho@khu.ac.kr [Graduate School of East-West Medical Science, Kyung Hee University, Gyeoggi-Do 446-701 (Korea, Republic of)

    2011-05-13

    Highlights: {yields} We screened and identified Tyrphostin A9, a receptor tyrosine kinase inhibitor as a strong mitochondria fission inducer. {yields} Tyrphostin A9 treatment promotes mitochondria dysfunction and contributes to cytotoxicity in cancer cells. {yields} Tyrphostin A9 induces apoptotic cell death through a Drp1-mediated pathway. {yields} Our studies suggest that Tyrphostin A9 induces mitochondria fragmentation and apoptotic cell death via Drp1 dependently. -- Abstract: Mitochondria dynamics controls not only their morphology but also functions of mitochondria. Therefore, an imbalance of the dynamics eventually leads to mitochondria disruption and cell death. To identify specific regulators of mitochondria dynamics, we screened a bioactive chemical compound library and selected Tyrphostin A9, a tyrosine kinase inhibitor, as a potent inducer of mitochondrial fission. Tyrphostin A9 treatment resulted in the formation of fragmented mitochondria filament. In addition, cellular ATP level was decreased and the mitochondrial membrane potential was collapsed in Tyr A9-treated cells. Suppression of Drp1 activity by siRNA or over-expression of a dominant negative mutant of Drp1 inhibited both mitochondrial fragmentation and cell death induced by Tyrpohotin A9. Moreover, treatment of Tyrphostin A9 also evoked mitochondrial fragmentation in other cells including the neuroblastomas. Taken together, these results suggest that Tyrphostin A9 induces Drp1-mediated mitochondrial fission and apoptotic cell death.

  20. Using microfluidics to study programmed cell death: A new approach

    DEFF Research Database (Denmark)

    Mark, Christina; Zor, Kinga; Heiskanen, Arto

    This project focuses on applying microfluidic tissue culture for electrochemical or optical measurements during programmed cell death (PCD) in barley aleurone layer to increase understanding of the underlying mechanisms of PCD in plants. Microfluidic tissue culture enables in vitro experiments...... to approach in vivo conditions. Microfluidics also allow implementation of a wide range of electrochemical or optical assays for online, real-time, parallel analysis of important parameters such as redox activity, O2 and H2O2 concentration, extracellular pH, cell viability and enzyme activity1,2. Currently...... a double-fluorescent probe-system also used by Fath et al5. Future challenges include integrating both these systems into a microfluidic device for plant tissue culture....

  1. Photodynamic Efficiency: From Molecular Photochemistry to Cell Death

    Directory of Open Access Journals (Sweden)

    Isabel O. L. Bacellar

    2015-08-01

    Full Text Available Photodynamic therapy (PDT is a clinical modality used to treat cancer and infectious diseases. The main agent is the photosensitizer (PS, which is excited by light and converted to a triplet excited state. This latter species leads to the formation of singlet oxygen and radicals that oxidize biomolecules. The main motivation for this review is to suggest alternatives for achieving high-efficiency PDT protocols, by taking advantage of knowledge on the chemical and biological processes taking place during and after photosensitization. We defend that in order to obtain specific mechanisms of cell death and maximize PDT efficiency, PSes should oxidize specific molecular targets. We consider the role of subcellular localization, how PS photochemistry and photophysics can change according to its nanoenvironment, and how can all these trigger specific cell death mechanisms. We propose that in order to develop PSes that will cause a breakthrough enhancement in the efficiency of PDT, researchers should first consider tissue and intracellular localization, instead of trying to maximize singlet oxygen quantum yields in in vitro tests. In addition to this, we also indicate many open questions and challenges remaining in this field, hoping to encourage future research.

  2. Mechanisms of palmitate-induced cell death in human osteoblasts

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    Krishanthi Gunaratnam

    2013-11-01

    Lipotoxicity is an overload of lipids in non-adipose tissues that affects function and induces cell death. Lipotoxicity has been demonstrated in bone cells in vitro using osteoblasts and adipocytes in coculture. In this condition, lipotoxicity was induced by high levels of saturated fatty acids (mostly palmitate secreted by cultured adipocytes acting in a paracrine manner. In the present study, we aimed to identify the underlying mechanisms of lipotoxicity in human osteoblasts. Palmitate induced autophagy in cultured osteoblasts, which was preceded by the activation of autophagosomes that surround palmitate droplets. Palmitate also induced apoptosis though the activation of the Fas/Jun kinase (JNK apoptotic pathway. In addition, osteoblasts could be protected from lipotoxicity by inhibiting autophagy with the phosphoinositide kinase inhibitor 3-methyladenine or by inhibiting apoptosis with the JNK inhibitor SP600125. In summary, we have identified two major molecular mechanisms of lipotoxicity in osteoblasts and in doing so we have identified a new potential therapeutic approach to prevent osteoblast dysfunction and death, which are common features of age-related bone loss and osteoporosis.

  3. Ion Channels Involved in Cell Volume Regulation

    DEFF Research Database (Denmark)

    Hoffmann, Else Kay

    2011-01-01

    This mini review outlines studies of cell volume regulation in two closely related mammalian cell lines: nonadherent Ehrlich ascites tumour cells (EATC) and adherent Ehrlich Lettre ascites (ELA) cells. Focus is on the regulatory volume decrease (RVD) that occurs after cell swelling, the volume...

  4. Induction of Neuronal Cell Death by Paraneoplastic Ma1 Antigen

    Science.gov (United States)

    Chen, Huai-Lu; D’Mello, Santosh R.

    2016-01-01

    Paraneoplastic Ma1 (PNMA1) is a member of a family of proteins involved in an autoimmune disorder called paraneoplastic neurological syndrome. Although it is widely expressed in brain, nothing is known about the function of PNMA1 in neurons. We find that PNMA1 expression is highest in the perinatal brain, a period during which developmentally regulated neuronal death occurs. PNMA1 expression increases in cerebellar granule neurons (CGNs) induced to die by low potassium (LK) and in cortical neurons following homocysteic acid (HCA) treament. Elevated PNMA1 expression is also observed in the degenerating striatum in two separate mouse models of Huntington’s disease, the R6/2 transgenic model and the 3-nitropropionic acid-induced chemical model. Suppression of endogenous PNMA1 expression inhibits LK-induced neuronal apoptosis. Ectopic expression of PNMA1 promotes apoptosis even in medium containing high potassium, a condition that normally ensures survival of CGNs. Deletion of the N-terminal half of the PNMA1 protein abrogates its apoptotic activity, whereas deletion of the C-terminal half renders the protein more toxic. Within the N-terminal half, the ability to induce neuronal death depends on the presence of a BH3-like domain. In addition to being necessary for apoptosis, the BH3-like domain is necessary for self-association of PNMA1. Apoptosis by PNMA1 expression is inhibited by overexpression of Bcl2, suggesting that PNMA1-induced neuronal death may depend on the binding of a proapoptotic member of the Bcl2 family to the BH3 domain. Taken together, our results suggest that PNMA1 is a proapoptotic protein in neurons, elevated expression of which may contribute to neurodegenerative disorders. PMID:20936693

  5. Inhibition of the sarco/endoplasmic reticulum (ER) Ca2+-ATPase by thapsigargin analogs induces cell death via ER Ca2+ depletion and the unfolded protein response

    DEFF Research Database (Denmark)

    Sehgal, Pankaj; Szalai, Paula; Olesen, Claus

    2017-01-01

    Calcium (Ca2+) is a fundamental regulator of cell signaling and function. Thapsigargin (Tg) blocks the sarco/endoplasmic reticulum (ER) Ca2+-ATPase (SERCA), disrupts Ca2+ homeostasis, and causes cell death. However, the exact mechanisms whereby SERCA-inhibition induces cell death are incompletely...... and their detrimental effects on cell viability. Furthermore, caspase activation and cell death were associated with a sustained unfolded protein response (UPR). We conclude that ER Ca2+ drainage and sustained UPR activation are key for initiation of apoptosis at low concentrations of Tg and Tg analogs, whereas high...

  6. Breast cancer cells with acquired antiestrogen resistance are sensitized to cisplatin-induced cell death

    DEFF Research Database (Denmark)

    Yde, Christina Westmose; Gyrd-Hansen, Mads; Lykkesfeldt, Anne E

    2007-01-01

    with parental MCF-7 cells. Our data show that Bcl-2 can protect antiestrogen-resistant breast cancer cells from cisplatin-induced cell death, indicating that the reduced expression of Bcl-2 in the antiestrogen-resistant cells plays a role in sensitizing the cells to cisplatin treatment....... for future breast cancer treatment. In this study, we have investigated the effect of the chemotherapeutic compound cisplatin using a panel of antiestrogen-resistant breast cancer cell lines established from the human breast cancer cell line MCF-7. We show that the antiestrogen-resistant cells...

  7. Necrosis, and then stress induced necrosis-like cell death, but not apoptosis, should be the preferred cell death mode for chemotherapy: clearance of a few misconceptions.

    Science.gov (United States)

    Zhang, Ju; Lou, Xiaomin; Jin, Longyu; Zhou, Rongjia; Liu, Siqi; Xu, Ningzhi; Liao, D Joshua

    2014-01-01

    Cell death overarches carcinogenesis and is a center of cancer researches, especially therapy studies. There have been many nomenclatures on cell death, but only three cell death modes are genuine, i.e. apoptosis, necrosis and stress-induced cell death (SICD). Like apoptosis, SICD is programmed. Like necrosis, SICD is a pathological event and may trigger regeneration and scar formation. Therefore, SICD has subtypes of stress-induced apoptosis-like cell death (SIaLCD) and stress-induced necrosis-like cell death (SInLCD). Whereas apoptosis removes redundant but healthy cells, SICD removes useful but ill or damaged cells. Many studies on cell death involve cancer tissues that resemble parasites in the host patients, which is a complicated system as it involves immune clearance of the alien cancer cells by the host. Cancer resembles an evolutionarily lower-level organism having a weaker apoptosis potential and poorer DNA repair mechanisms. Hence, targeting apoptosis for cancer therapy, i.e. killing via SIaLCD, will be less efficacious and more toxic. On the other hand, necrosis of cancer cells releases cellular debris and components to stimulate immune function, thus counteracting therapy-caused immune suppression and making necrosis better than SIaLCD for chemo drug development.

  8. Eryptosis: An Erythrocyte’s Suicidal Type of Cell Death

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    Lisa Repsold

    2018-01-01

    Full Text Available Erythrocytes play an important role in oxygen and carbon dioxide transport. Although erythrocytes possess no nucleus or mitochondria, they fulfil several metabolic activities namely, the Embden-Meyerhof pathway, as well as the hexose monophosphate shunt. Metabolic processes within the erythrocyte contribute to the morphology/shape of the cell and important constituents are being kept in an active, reduced form. Erythrocytes undergo a form of suicidal cell death called eryptosis. Eryptosis results from a wide variety of contributors including hyperosmolarity, oxidative stress, and exposure to xenobiotics. Eryptosis occurs before the erythrocyte has had a chance to be naturally removed from the circulation after its 120-day lifespan and is characterised by the presence of membrane blebbing, cell shrinkage, and phosphatidylserine exposure that correspond to nucleated cell apoptotic characteristics. After eryptosis is triggered there is an increase in cytosolic calcium (Ca2+ ion levels. This increase causes activation of Ca2+-sensitive potassium (K+ channels which leads to a decrease in intracellular potassium chloride (KCl and shrinkage of the erythrocyte. Ceramide, produced by sphingomyelinase from the cell membrane’s sphingomyelin, contributes to the occurrence of eryptosis. Eryptosis ensures healthy erythrocyte quantity in circulation whereas excessive eryptosis may set an environment for the clinical presence of pathophysiological conditions including anaemia.

  9. Cell death induction by the BH3 mimetic GX15-070 in thyroid carcinoma cells.

    Science.gov (United States)

    Broecker-Preuss, Martina; Viehof, Jan; Jastrow, Holger; Becher-Boveleth, Nina; Fuhrer, Dagmar; Mann, Klaus

    2015-07-22

    The evasion of cell death is one of the hallmarks of cancer, contributing to both tumor progression and resistance to therapy. Dedifferentiated and anaplastic thyroid carcinomas that do not take up radioiodine are resistant to conventional anticancer treatments and patients with these tumors are difficult to treat. BH3 mimetics are a new class of drugs that target anti-apoptotic proteins of the BCL-2 family and promote cell death. The purpose of this study was to analyze the molecular effects of the BH3 mimetic GX15-070 on thyroid carcinoma cell lines and to characterize cell death induced by GX15-070. A total of 17 cell lines derived from follicular, papillary, and anaplastic thyroid carcinomas were treated with GX15-070. Cell viability was measured with MTT assay while cell cycle phase distribution and subG1 peaks were determined after propidium iodide staining. We assessed cell death via the caspase 3/7 activity, caspase cleavage products, lactate dehydrogenase (LDH) liberation assays, and a LC3 analysis by western blot. Ultrastructural changes were analysed by electron microscopy of GX15-070-treated cells. After GX15-070 treatment, the number of viable cells was decreased in all cell lines examined, with IC50 values ranging from 48nM to 3.25 μM. We observed biochemical markers of autophagic cell death and necrosis like LC3 conversion and LDH release after the GX15-070 treatment. Electron microscopy revealed several common characteristic ultrastructural changes like swelling of mitochondria, dilatation of rough endoplasmic reticulum, membrane blebbing and formation of vacuoles. GX15-070 treatment induced DNA fragmentation detected by subG1-peak induction and an arrest in G1 phase of the cell cycle. Caspase activation after GX15-070 incubation was detected but had no effect on viability of cells. With these experiments we demonstrated the efficacy of the BH3 mimetic drug GX15-070 acting against dedifferentiated thyroid carcinoma cells of various histological

  10. miR-181 interacts with signaling adaptor molecule DENN/MADD and enhances TNF-induced cell death.

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    Samira Ghorbani

    Full Text Available MicroRNAs are small noncoding RNAs, which regulate the expression of protein coding transcripts through mRNA degradation or translational inhibition. Numerous reports have highlighted the role of miRNAs in regulating cell death pathways including the expression of genes involved in the induction of apoptosis. Tumor necrosis factor alpha (TNF-α is a proinflammatory cytokine which can send pro-death signals through its receptor TNFR1. Diverse adaptor molecules including DENN/MADD adaptor protein have been shown to modulate TNF-α pro-death signaling via recruitment of MAP kinases to TNFR1 and activation of pro-survival NFκB signaling. Herein, we investigated the role of microRNA-181 (miR-181 in regulating DENN/MADD expression levels and its subsequent effects on TNF-α-induced cell death. Using bioinformatics analyses followed by luciferase reporter assays we showed that miR-181 interacts with the 3' UTR of DENN/MADD transcripts. miR-181 overexpression also led to decreased endogenous DENN/MADD mRNA levels in L929 murine fibroblasts. Flow cytometric analysis of miR-181 transfected cells showed this miRNA accentuates mitochondrial membrane potential loss caused by TNF-α. These findings were associated with enhanced apoptosis of L929 cells following TNF-α treatment. Overall, these data point to the potential role of miR-181 in regulating TNF-α pro-death signaling, which could be of importance from pathogenesis and therapeutic perspectives in inflammatory disorders associated with tissue degeneration and cell death.

  11. Cell Death Pathways and Phthalocyanine as an Efficient Agent for Photodynamic Cancer Therapy

    Science.gov (United States)

    Mfouo-Tynga, Ivan; Abrahamse, Heidi

    2015-01-01

    The mechanisms of cell death can be predetermined (programmed) or not and categorized into apoptotic, autophagic and necrotic pathways. The process of Hayflick limits completes the execution of death-related mechanisms. Reactive oxygen species (ROS) are associated with oxidative stress and subsequent cytodamage by oxidizing and degrading cell components. ROS are also involved in immune responses, where they stabilize and activate both hypoxia-inducible factors and phagocytic effectors. ROS production and presence enhance cytodamage and photodynamic-induced cell death. Photodynamic cancer therapy (PDT) uses non-toxic chemotherapeutic agents, photosensitizer (PS), to initiate a light-dependent and ROS-related cell death. Phthalocyanines (PCs) are third generation and stable PSs with improved photochemical abilities. They are effective inducers of cell death in various neoplastic models. The metallated PCs localize in critical cellular organelles and are better inducers of cell death than other previous generation PSs as they favor mainly apoptotic cell death events. PMID:25955645

  12. Cell Death Pathways and Phthalocyanine as an Efficient Agent for Photodynamic Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Ivan Mfouo-Tynga

    2015-05-01

    Full Text Available The mechanisms of cell death can be predetermined (programmed or not and categorized into apoptotic, autophagic and necrotic pathways. The process of Hayflick limits completes the execution of death-related mechanisms. Reactive oxygen species (ROS are associated with oxidative stress and subsequent cytodamage by oxidizing and degrading cell components. ROS are also involved in immune responses, where they stabilize and activate both hypoxia-inducible factors and phagocytic effectors. ROS production and presence enhance cytodamage and photodynamic-induced cell death. Photodynamic cancer therapy (PDT uses non-toxic chemotherapeutic agents, photosensitizer (PS, to initiate a light-dependent and ROS-related cell death. Phthalocyanines (PCs are third generation and stable PSs with improved photochemical abilities. They are effective inducers of cell death in various neoplastic models. The metallated PCs localize in critical cellular organelles and are better inducers of cell death than other previous generation PSs as they favor mainly apoptotic cell death events.

  13. XIAP is not required for human tumor cell survival in the absence of an exogenous death signal

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    Peach Robert

    2010-01-01

    Full Text Available Abstract Background The X-linked Inhibitor of Apoptosis (XIAP has attracted much attention as a cancer drug target. It is the only member of the IAP family that can directly inhibit caspase activity in vitro, and it can regulate apoptosis and other biological processes through its C-terminal E3 ubiquitin ligase RING domain. However, there is controversy regarding XIAP's role in regulating tumor cell proliferation and survival under normal growth conditions in vitro. Methods We utilized siRNA to systematically knock down XIAP in ten human tumor cell lines and then monitored both XIAP protein levels and cell viability over time. To examine the role of XIAP in the intrinsic versus extrinsic cell death pathways, we compared the viability of XIAP depleted cells treated either with a variety of mechanistically distinct, intrinsic pathway inducing agents, or the canonical inducer of the extrinsic pathway, TNF-related apoptosis-inducing ligand (TRAIL. Results XIAP knockdown had no effect on the viability of six cell lines, whereas the effect in the other four was modest and transient. XIAP knockdown only sensitized tumor cells to TRAIL and not the mitochondrial pathway inducing agents. Conclusions These data indicate that XIAP has a more central role in regulating death receptor mediated apoptosis than it does the intrinsic pathway mediated cell death.

  14. Therapeutic strategies of drug repositioning targeting autophagy to induce cancer cell death: from pathophysiology to treatment.

    Science.gov (United States)

    Yoshida, Go J

    2017-03-09

    The 2016