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Sample records for delayed cell death

  1. Improving Accuracy in Arrhenius Models of Cell Death: Adding a Temperature-Dependent Time Delay.

    PubMed

    Pearce, John A

    2015-12-01

    The Arrhenius formulation for single-step irreversible unimolecular reactions has been used for many decades to describe the thermal damage and cell death processes. Arrhenius predictions are acceptably accurate for structural proteins, for some cell death assays, and for cell death at higher temperatures in most cell lines, above about 55 °C. However, in many cases--and particularly at hyperthermic temperatures, between about 43 and 55 °C--the particular intrinsic cell death or damage process under study exhibits a significant "shoulder" region that constant-rate Arrhenius models are unable to represent with acceptable accuracy. The primary limitation is that Arrhenius calculations always overestimate the cell death fraction, which leads to severely overoptimistic predictions of heating effectiveness in tumor treatment. Several more sophisticated mathematical model approaches have been suggested and show much-improved performance. But simpler models that have adequate accuracy would provide useful and practical alternatives to intricate biochemical analyses. Typical transient intrinsic cell death processes at hyperthermic temperatures consist of a slowly developing shoulder region followed by an essentially constant-rate region. The shoulder regions have been demonstrated to arise chiefly from complex functional protein signaling cascades that generate delays in the onset of the constant-rate region, but may involve heat shock protein activity as well. This paper shows that acceptably accurate and much-improved predictions in the simpler Arrhenius models can be obtained by adding a temperature-dependent time delay. Kinetic coefficients and the appropriate time delay are obtained from the constant-rate regions of the measured survival curves. The resulting predictions are seen to provide acceptably accurate results while not overestimating cell death. The method can be relatively easily incorporated into numerical models. Additionally, evidence is presented

  2. Improving Accuracy in Arrhenius Models of Cell Death: Adding a Temperature-Dependent Time Delay.

    PubMed

    Pearce, John A

    2015-12-01

    The Arrhenius formulation for single-step irreversible unimolecular reactions has been used for many decades to describe the thermal damage and cell death processes. Arrhenius predictions are acceptably accurate for structural proteins, for some cell death assays, and for cell death at higher temperatures in most cell lines, above about 55 °C. However, in many cases--and particularly at hyperthermic temperatures, between about 43 and 55 °C--the particular intrinsic cell death or damage process under study exhibits a significant "shoulder" region that constant-rate Arrhenius models are unable to represent with acceptable accuracy. The primary limitation is that Arrhenius calculations always overestimate the cell death fraction, which leads to severely overoptimistic predictions of heating effectiveness in tumor treatment. Several more sophisticated mathematical model approaches have been suggested and show much-improved performance. But simpler models that have adequate accuracy would provide useful and practical alternatives to intricate biochemical analyses. Typical transient intrinsic cell death processes at hyperthermic temperatures consist of a slowly developing shoulder region followed by an essentially constant-rate region. The shoulder regions have been demonstrated to arise chiefly from complex functional protein signaling cascades that generate delays in the onset of the constant-rate region, but may involve heat shock protein activity as well. This paper shows that acceptably accurate and much-improved predictions in the simpler Arrhenius models can be obtained by adding a temperature-dependent time delay. Kinetic coefficients and the appropriate time delay are obtained from the constant-rate regions of the measured survival curves. The resulting predictions are seen to provide acceptably accurate results while not overestimating cell death. The method can be relatively easily incorporated into numerical models. Additionally, evidence is presented

  3. Enhancement of suicidal DNA vaccine potency by delaying suicidal DNA-induced cell death.

    PubMed

    Kim, T W; Hung, C-F; Juang, J; He, L; Hardwick, J M; Wu, T-C

    2004-02-01

    DNA-based alphaviral RNA replicon vectors, also called suicidal DNA vectors, alleviate the concerns of integration or transformation related to conventional DNA vectors since suicidal DNA vectors eventually cause apoptosis of transfected cells. However, the expression of inserted genes in these vectors is transient and the potency of suicidal DNA vaccines may be compromised because of apoptotic cell death. Therefore, to enhance the immune response to the human papillomavirus type 16 (HPV-16) E7 antigen, we generated a DNA-based Semliki Forest virus vector, pSCA1, encoding E7 fused with BCL-xL, an antiapoptotic member of the BCL-2 family. Our results indicated that pSCA1 encoding E7/BCL-xL fusion protein delayed cell death in the pSCA1-transfected dendritic cell line and generated significantly higher E7-specific CD8(+) T-cell-mediated immune responses and better antitumor effects than pSCA1 encoding wild-type E7 gene in vaccinated mice. The antiapoptotic function of BCL-xL is important for the enhancement of antigen-specific CD8(+) T-cell responses in vaccinated mice, because a point mutant of BCL-xL lacking antiapoptotic function was ineffective. These results suggest that strategies to delay suicidal DNA-induced cell death using antiapoptotic proteins may greatly enhance the potency of suicidal DNA.

  4. Early and delayed reproductive death in human cells exposed to high energy iron-ion beams

    NASA Astrophysics Data System (ADS)

    Bettega, D.; Calzolari, P.; Doneda, L.; Durante, M.; Tallone, L.

    For radiation protection of the astronauts it is important to know both the acute and the late effects of charged particles. Iron is the most abundant high charge and energy (HZE) specie in galactic cosmic radiation. (HZE) ions are considered to be the major contributors to equivalent dose in space, but the Relative Biological Effectiveness of HZE particles has large uncertainties, expecially for late effects. We have determined early and delayed reproductive death in human fibroblast cells (AG1522) exposed to iron ion beams of energies between 0.2 and 1 GeV/n. The cells were irradiated at the HIMAC accelerator in Chiba (0.2 and 0.5 GeV/n) and at the AGS accelerator at the NASA Space Radiation Laboratory in Brookhaven (1 GeV/n). For each beam the dose--effect curves were measured at least twice in the dose range between 0.5 and 2 Gy. 60 Co gamma rays were used as reference radiation. The following results were obtained: 1) the 1 GeV/n beam effectiveness for inactivation of the AG1522 cells is higher than that of any other beam. 2) the progeny of the irradiated cells show the presence of delayed damage in the form of reproductive death for all the beams with the 1 GeV/n being the most effective. 3) the relative biological effectiveness of the iron beams is higher for delayed compared to early reproductive death. A comparison with preliminary results obtained with 970 MeV/n Ti and 490 MeV/n Si ions will be also reported .

  5. Chikungunya virus–induced autophagy delays caspase-dependent cell death

    PubMed Central

    Joubert, Pierre-Emmanuel; Werneke, Scott W.; de la Calle, Claire; Guivel-Benhassine, Florence; Giodini, Alessandra; Peduto, Lucie; Levine, Beth; Schwartz, Olivier; Lenschow, Deborah J.

    2012-01-01

    Autophagy is an important survival pathway and can participate in the host response to infection. Studying Chikungunya virus (CHIKV), the causative agent of a major epidemic in India, Southeast Asia, and southern Europe, we reveal a novel mechanism by which autophagy limits cell death and mortality after infection. We use biochemical studies and single cell multispectral assays to demonstrate that direct infection triggers both apoptosis and autophagy. CHIKV-induced autophagy is mediated by the independent induction of endoplasmic reticulum and oxidative stress pathways. These cellular responses delay apoptotic cell death by inducing the IRE1α–XBP-1 pathway in conjunction with ROS-mediated mTOR inhibition. Silencing of autophagy genes resulted in enhanced intrinsic and extrinsic apoptosis, favoring viral propagation in cultured cells. Providing in vivo evidence for the relevance of our findings, Atg16LHM mice, which display reduced levels of autophagy, exhibited increased lethality and showed a higher sensitivity to CHIKV-induced apoptosis. Based on kinetic studies and the observation that features of apoptosis and autophagy were mutually exclusive, we conclude that autophagy inhibits caspase-dependent cell death but is ultimately overwhelmed by viral replication. Our study suggests that inducers of autophagy may limit the pathogenesis of acute Chikungunya disease. PMID:22508836

  6. Haem oxygenase delays programmed cell death in wheat aleurone layers by modulation of hydrogen peroxide metabolism.

    PubMed

    Wu, Mingzhu; Huang, Jingjing; Xu, Sheng; Ling, Tengfang; Xie, Yanjie; Shen, Wenbiao

    2011-01-01

    Haem oxygenase-1 (HO-1) confers protection against a variety of oxidant-induced cell and tissue injury in animals and plants. In this report, it is confirmed that programmed cell death (PCD) in wheat aleurone layers is stimulated by GA and prevented by ABA. Meanwhile, HO activity and HO-1 protein expression exhibited lower levels in GA-treated layers, whereas the hydrogen peroxide (H(2)O(2)) content was apparently increased. The pharmacology approach illustrated that scavenging or accumulating H(2)O(2) either delayed or accelerated GA-induced PCD. Furthermore, pretreatment with the HO-1 specific inhibitor, zinc protoporphyrin IX (ZnPPIX), before exposure to GA, not only decreased HO activity but also accelerated GA-induced PCD significantly. The application of the HO-1 inducer, haematin, and the enzymatic reaction product of HO, carbon monoxide (CO) aqueous solution, both of which brought about a noticeable induction of HO expression, substantially prevented GA-induced PCD. These effects were reversed when ZnPPIX was added, suggesting that HO in vivo played a role in delaying PCD. Meanwhile, catalase (CAT) and ascorbate peroxidase (APX) activities or transcripts were enhanced by haematin, CO, or bilirubin (BR), the catalytic by-product of HO. This enhancement resulted in a decrease in H(2)O(2) production and a delay in PCD. In addition, the antioxidants butylated hydroxytoluene (BHT), dithiothreitol (DTT), and ascorbic acid (AsA) were able not only to delay PCD but also to mimic the effects of haematin and CO on HO up-regulation. Overall, the above results suggested that up-regulation of HO expression delays PCD through the down-regulation of H(2)O(2) production.

  7. Delayed luminescence to monitor programmed cell death induced by berberine on thyroid cancer cells

    NASA Astrophysics Data System (ADS)

    Scordino, Agata; Campisi, Agata; Grasso, Rosaria; Bonfanti, Roberta; Gulino, Marisa; Iauk, Liliana; Parenti, Rosalba; Musumeci, Francesco

    2014-11-01

    Correlation between apoptosis and UVA-induced ultraweak photon emission delayed luminescence (DL) from tumor thyroid cell lines was investigated. In particular, the effects of berberine, an alkaloid that has been reported to have anticancer activities, on two cancer cell lines were studied. The FTC-133 and 8305C cell lines, as representative of follicular and anaplastic thyroid human cancer, respectively, were chosen. The results show that berberine is able to arrest cell cycle and activate apoptotic pathway as shown in both cell lines by deoxyribonucleic acid fragmentation, caspase-3 cleavage, p53 and p27 protein overexpression. In parallel, changes in DL spectral components after berberine treatment support the hypothesis that DL from human cells originates mainly from mitochondria, since berberine acts especially at the mitochondrial level. The decrease of DL blue component for both cell lines could be related to the decrease of intra-mitochondrial nicotinamide adenine dinucleotide and may be a hallmark of induced apoptosis. In contrast, the response in the red spectral range is different for the two cell lines and may be ascribed to a different iron homeostasis.

  8. Excitotoxic cell death induces delayed proliferation of endogenous neuroprogenitor cells in organotypic slice cultures of the rat spinal cord.

    PubMed

    Mazzone, G L; Mladinic, M; Nistri, A

    2013-10-31

    The aim of the present report was to investigate whether, in the mammalian spinal cord, cell death induced by transient excitotoxic stress could trigger activation and proliferation of endogenous neuroprogenitor cells as a potential source of a lesion repair process and the underlying time course. Because it is difficult to address these issues in vivo, we used a validated model of spinal injury based on rat organotypic slice cultures that retain the fundamental tissue cytoarchitecture and replicate the main characteristics of experimental damage to the whole spinal cord. Excitotoxicity evoked by 1 h kainate application produced delayed neuronal death (40%) peaking after 1 day without further losses or destruction of white matter cells for up to 2 weeks. After 10 days, cultures released a significantly larger concentration of endogenous glutamate, suggesting functional network plasticity. Indeed, after 1 week the total number of cells had returned to untreated control level, indicating substantial cell proliferation. Activation of progenitor cells started early as they spread outside the central area, and persisted for 2 weeks. Although expression of the neuronal progenitor phenotype was observed at day 3, peaked at 1 week and tapered off at 2 weeks, very few cells matured to neurons. Astroglia precursors started proliferating later and matured at 2 weeks. These data show insult-related proliferation of endogenous spinal neuroprogenitors over a relatively brief time course, and delineate a narrow temporal window for future experimental attempts to drive neuronal maturation and for identifying the factors regulating this process.

  9. Histone deacetylase inhibitors sodium butyrate and valproic acid delay spontaneous cell death in purified rat retinal ganglion cells

    PubMed Central

    Boyle, Jennifer; Pielen, Amelie; Lagrèze, Wolf Alexander

    2011-01-01

    Purpose Histone deacetylase inhibitors (HDACi) have neuroprotective effects under various neurodegenerative conditions, e.g., after optic nerve crush (ONC). HDACi-mediated protection of central neurons by increased histone acetylation has not previously been demonstrated in rat retinal ganglion cells (RGCs), although epigenetic changes were shown to be associated with cell death after ONC. We investigated whether HDACi can delay spontaneous cell death in purified rat RGCs and analyzed concomitant histone acetylation levels. Methods RGCs were purified from newborn (postnatal day [P] 0–P2) rat retinas by immunopanning with antibodies against Thy-1.1 and culturing in serum-free medium for 2 days. RGCs were treated with HDACi, each at several different concentrations: 0.1–10 mM sodium butyrate (SB), 0.1–2 mM valproic acid (VPA), or 0.5–10 nM trichostatin A (TSA). Negative controls were incubated in media alone, while positive controls were incubated in 0.05–0.4 IU/µl erythropoietin. Survival was quantified by counting viable cells using phase-contrast microscopy. The expression of acetylated histone proteins (AcH) 3 and 4 was analyzed in RGCs by immunohistochemistry. Results SB and VPA enhanced RGC survival in culture, with both showing a maximum effect at 0.1 mM (increase in survival to 188% and 163%, respectively). Their neuroprotective effect was comparable to that of erythropoietin at 0.05 IU/µl. TSA 0.5–1.0 nM showed no effect on RGC survival, and concentrations ≥5 nM increased RGC death. AcH3 and AcH4 levels were only significantly increased in RGCs treated with 0.1 mM SB. VPA 0.1 mM produced only a slight effect on histone acetylation. Conclusions Millimolar concentrations of SB and VPA delayed spontaneous cell death in purified RGCs; however, significantly increased histone acetylation levels were only detectable in RGCs after SB treatment. As the potent HDACi TSA was not neuroprotective, mechanisms other than histone acetylation may be the

  10. Role of Rac1 GTPase in JNK signaling and delayed neuronal cell death following global cerebral ischemia.

    PubMed

    Zhang, Quan-Guang; Wang, Ruimin; Han, Dong; Dong, Yan; Brann, Darrell W

    2009-04-10

    The overall goal of this study was to determine the role of Rac1 in POSH/MLK/JNK signaling and delayed neuronal cell death following cerebral ischemia. Temporal studies revealed that Rac1 GTPase activation was significantly elevated in hippocampus CA1 at 10 min to 72 h after cerebral ischemia reperfusion, with peak levels 30 min to 6 h after reperfusion. Total Rac1 protein levels were not significantly changed following cerebral ischemia. Rac1 has been shown to interact with POSH (plenty of SH3s), a scaffold protein that binds to and regulates MLK3 and JNK activation. Co-immunoprecipitation (Co-IP) studies revealed that POSH-Rac1-MLK3 complex formation displayed a significant and prolonged elevation after reperfusion, with a correlative increase in phosphorylation/activation of MLK3 as compared to sham controls. Intracerebroventricular administration of Rac1 antisense oligonucleotides (AS-ODNs) significantly attenuated Rac1 levels and Rac1 activation at 30 min after reperfusion, with a correlated significant attenuation of POSH-MLK3-Rac1 complex formation and MLK3 activation in hippocampus CA1. Infusion of Rac1 AS-ODNs also significantly attenuated post-ischemic activation of JNK, downstream of MLK3, and strongly protected the hippocampus CA1 from ischemic damage. Missense oligos had no effect on any of the parameters measured. The Rac1 AS-ODNs results were further confirmed by administration of a Rac1 inhibitor (NSC23766), which markedly attenuated activation of Rac1 and JNK, and significantly attenuated apoptotic delayed neuronal cell death following cerebral ischemia. As a whole, these studies demonstrate an important role for Rac1 in activation of the prodeath MLK3-JNK kinase signaling pathway and delayed neuronal cell death following cerebral ischemia.

  11. A delay prior to mitotic entry triggers caspase 8-dependent cell death in p53-deficient Hela and HCT-116 cells.

    PubMed

    Silva, Victoria C; Plooster, Melissa; Leung, Jessica C; Cassimeris, Lynne

    2015-01-01

    Stathmin/Oncoprotein 18, a microtubule destabilizing protein, is required for survival of p53-deficient cells. Stathmin-depleted cells are slower to enter mitosis, but whether delayed mitotic entry triggers cell death or whether stathmin has a separate pro-survival function was unknown. To test these possibilities, we abrogated the cell cycle delay by inhibiting Wee1 in synchronized, stathmin-depleted cells and found that apoptosis was reduced to control levels. Synchronized cells treated with a 4 hour pulse of inhibitors to CDK1 or both Aurora A and PLK1 delayed mitotic entry and apoptosis was triggered only in p53-deficient cells. We did not detect mitotic defects downstream of the delayed mitotic entry, indicating that cell death is activated by a mechanism distinct from those activated by prolonged mitotic arrest. Cell death is triggered by initiator caspase 8, based on its cleavage to the active form and by rescue of viability after caspase 8 depletion or treatment with a caspase 8 inhibitor. In contrast, initiator caspase 9, activated by prolonged mitotic arrest, is not activated and is not required for apoptosis under our experimental conditions. P53 upregulates expression of cFLIPL, a protein that blocks caspase 8 activation. cFLIPL levels are lower in cells lacking p53 and these levels are reduced to a greater extent after stathmin depletion. Expression of FLAG-tagged cFLIPL in p53-deficient cells rescues them from apoptosis triggered by stathmin depletion or CDK1 inhibition during G2. These data indicate that a cell cycle delay in G2 activates caspase 8 to initiate apoptosis specifically in p53-deficient cells.

  12. At the core of survival: autophagy delays the onset of both apoptotic and necrotic cell death in a model of ischemic cell injury.

    PubMed

    Loos, B; Genade, S; Ellis, B; Lochner, A; Engelbrecht, A-M

    2011-06-10

    Ischemic cell injury leads to cell death. Three main morphologies have been described: apoptosis, cell death with autophagy and necrosis. Their inherent dynamic nature, a point of no return (PONR) and molecular overlap have been stressed. The relationship between a defined cell death type and the severity of injury remains unclear. The functional role of autophagy and its effects on cell death onset is largely unknown. In this study we report a differential induction of cell death, which is dependent on the severity and duration of an ischemic insult. We show that mild ischemia leads to the induction of autophagy and apoptosis, while moderate or severe ischemia induces both apoptotic and necrotic cell death without increased autophagy. The autophagic response during mild injury was associated with an ATP surge. Real-time imaging and Fluorescence Resonance Energy Transfer (FRET) revealed that increased autophagy delays the PONR of both apoptosis and necrosis significantly. Blocking autophagy shifted PONR to an earlier point in time. Our results suggest that autophagic activity directly alters intracellular metabolic parameters, responsible for maintaining mitochondrial membrane potential and cellular membrane integrity. A similar treatment also improved functional recovery in the perfused rat heart. Taken together, we demonstrate a novel finding: autophagy is implicated only in mild injury and positions the PONR in cell death. PMID:21420401

  13. Amplitude death in networks of delay-coupled delay oscillators.

    PubMed

    Höfener, Johannes M; Sethia, Gautam C; Gross, Thilo

    2013-09-28

    Amplitude death is a dynamical phenomenon in which a network of oscillators settles to a stable state as a result of coupling. Here, we study amplitude death in a generalized model of delay-coupled delay oscillators. We derive analytical results for degree homogeneous networks which show that amplitude death is governed by certain eigenvalues of the network's adjacency matrix. In particular, these results demonstrate that in delay-coupled delay oscillators amplitude death can occur for arbitrarily large coupling strength k. In this limit, we find a region of amplitude death which already occurs at small coupling delays that scale with 1/k. We show numerically that these results remain valid in random networks with heterogeneous degree distribution.

  14. The Hydrogen Sulfide Donor NaHS Delays Programmed Cell Death in Barley Aleurone Layers by Acting as an Antioxidant.

    PubMed

    Zhang, Ying-Xin; Hu, Kang-Di; Lv, Kai; Li, Yan-Hong; Hu, Lan-Ying; Zhang, Xi-Qi; Ruan, Long; Liu, Yong-Sheng; Zhang, Hua

    2015-01-01

    H2S is a signaling molecule in plants and animals. Here we investigated the effects of H2S on programmed cell death (PCD) in barley (Hordeum vulgare L.) aleurone layers. The H2S donor NaHS significantly delayed PCD in aleurone layers isolated from imbibed embryoless barley grain. NaHS at 0.25 mM effectively reduced the accumulation of superoxide anion (·O2 (-)), hydrogen peroxide (H2O2), and malondialdehyde (MDA), promoted the activity of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and decreased those of lipoxygenase (LOX) in isolated aleurone layers. Quantitative-PCR showed that NaHS treatment of aleurone tissue led to enhanced transcript levels of the antioxidant genes HvSOD1, HvAPX, HvCAT1, and HvCAT2 and repressed transcript levels of HvLOX (lipoxygenase gene) and of two cysteine protease genes HvEPA and HvCP3-31. NaHS treatment in gibberellic acid- (GA-) treated aleurone layers also delayed the PCD process, reduced the content of ·O2 (-), and increased POD activity while decreasing LOX activity. Furthermore, α-amylase secretion in barley aleurone layers was enhanced by NaHS treatment regardless of the presence or absence of GA. These data imply that H2S acted as an antioxidant in delaying PCD and enhances α-amylase secretion regardless of the presence of GA in barley aleurone layers.

  15. Cell acidification in apoptosis: granulocyte colony-stimulating factor delays programmed cell death in neutrophils by up-regulating the vacuolar H(+)-ATPase.

    PubMed Central

    Gottlieb, R A; Giesing, H A; Zhu, J Y; Engler, R L; Babior, B M

    1995-01-01

    Neutrophils in tissue culture spontaneously undergo programmed cell death (apoptosis), a process characterized by well-defined morphological alterations affecting the cell nucleus. We found that these morphological changes were preceded by intracellular acidification and that acidification and the apoptotic changes in nuclear morphology were both delayed by granulocyte colony-stimulating factor (G-CSF). Among the agents that defend neutrophils against intracellular acidification is a vacuolar H(+)-ATPase that pumps protons out of the cytosol. When this proton pump was inhibited by bafilomycin A1, G-CSF no longer protected the neutrophils against apoptosis. We conclude that G-CSF delays apoptosis in neutrophils by up-regulating the cells' vacuolar H(+)-ATPase and that intracellular acidification is an early event in the apoptosis program. Images Fig. 1 Fig. 2 PMID:7541139

  16. Cell death, chromosome damage and mitotic delay in normal human, ataxia telangiectasia and retinoblastoma fibroblasts after x-irradiation.

    PubMed

    Zampetti-Bosseler, F; Scott, D

    1981-05-01

    We recently showed (Scott and Zampetti-Bosseler 1980) that X-ray sensitive mouse lymphoma cells sustain more chromosome damage, mitotic delay and spindle defects than X-ray resistant cells. We proposed that (a) chromosome aberrations contribute much more to lethality than spindle defects, and (b) that DNA lesions are less effectively repaired in the sensitive cells and give rise to more G2 mitotic delay and chromosome aberrations. Our present results on human fibroblasts with reported differential sensitivity to ionizing radiation (i.e. normal donors and patients with ataxia telangiectasia and retinoblastoma) support the first hypothesis since we observed a positive correlation between chromosome aberration frequencies and cell killing and no induced spindle defects. Our second hypothesis is however not substantiated since X-ray sensitive fibroblasts from the ataxia patient suffered less mitotic delay than cells from normal donors. A common lesion for mitotic delay and chromosome aberrations can still be assumed by adopting the hypothesis of Painter and Young (1981) that the defect in ataxia cells is not in repair but in a failure of DNA damage to initiate mitotic delay. In contrast to other reports, we found the retinoblastoma cells to be of normal radiation sensitivity (cell killing and aberration).

  17. Thinking about Death Reduces Delay Discounting

    PubMed Central

    Kelley, Nicholas J.; Schmeichel, Brandon J.

    2015-01-01

    The current study tested competing predictions regarding the effect of mortality salience on delay discounting. One prediction, based on evolutionary considerations, was that reminders of death increase the value of the present. Another prediction, based in part on construal level theory, was that reminders of death increase the value of the future. One-hundred eighteen participants thought about personal mortality or a control topic and then completed an inter-temporal choice task pitting the chance to gain $50 now against increasingly attractive rewards three months later. Consistent with the hypothesis inspired by construal theory, participants in the mortality salience condition traded $50 now for $66.67 in three months, whereas participants in the dental pain salience condition required $72.84 in three months in lieu of $50 now. Thus, participants in the mortality salience condition discounted future monetary gains less than other participants, suggesting that thoughts of death may increase the subjective value of the future. PMID:26630664

  18. Depletion of Aurora-A in zebrafish causes growth retardation due to mitotic delay and p53-dependent cell death.

    PubMed

    Jeon, Hee-Yeon; Lee, Hyunsook

    2013-03-01

    Aurora-A is a serine/threonine mitotic kinase that is required for centrosome maturation. Many cancer cells over-express Aurora-A, and several reports have suggested that Aurora-A has prognostic value in the clinical treatment of cancer. Therefore, inhibitors for Aurora-A kinase have been developed. However, studies on Aurora-A are largely performed in cancer cell lines and are sometimes controversial. For effective evaluation of Aurora-A inhibitors in cancer treatment, it is essential to understand its function at the organism level. Here, we report the crucial functions of Aurora-A in homeostasis of spindle organization in mitosis using zebrafish embryogenesis as a model system. Using morpholino technology, we show that depletion of Aurora-A in zebrafish embryogenesis results in short bent trunks, accompanied by growth retardation and eventual cell death. Live-imaging and immunofluorescence analyses of the embryos revealed that the developmental defects are due to problems in mitosis, manifested through monopolar and disorganized spindle formation. Aurora-A-depleted cells exhibited mitotic arrest with congression failure, leading to activation of the spindle assembly checkpoint. Cell death in the absence of Aurora-A was partially rescued by co-injection of the p53 morpholino, suggesting that apoptosis after Aurora-A depletion is p53-dependent. The clinical implications of these results relate to the indication that Aurora-A inhibitors may be effective towards cancers with intact p53.

  19. Modeling delay in genetic networks: From delay birth-death processes to delay stochastic differential equations

    SciTech Connect

    Gupta, Chinmaya; López, José Manuel; Azencott, Robert; Ott, William; Bennett, Matthew R.; Josić, Krešimir

    2014-05-28

    Delay is an important and ubiquitous aspect of many biochemical processes. For example, delay plays a central role in the dynamics of genetic regulatory networks as it stems from the sequential assembly of first mRNA and then protein. Genetic regulatory networks are therefore frequently modeled as stochastic birth-death processes with delay. Here, we examine the relationship between delay birth-death processes and their appropriate approximating delay chemical Langevin equations. We prove a quantitative bound on the error between the pathwise realizations of these two processes. Our results hold for both fixed delay and distributed delay. Simulations demonstrate that the delay chemical Langevin approximation is accurate even at moderate system sizes. It captures dynamical features such as the oscillatory behavior in negative feedback circuits, cross-correlations between nodes in a network, and spatial and temporal information in two commonly studied motifs of metastability in biochemical systems. Overall, these results provide a foundation for using delay stochastic differential equations to approximate the dynamics of birth-death processes with delay.

  20. Modeling delay in genetic networks: From delay birth-death processes to delay stochastic differential equations

    NASA Astrophysics Data System (ADS)

    Gupta, Chinmaya; López, José Manuel; Azencott, Robert; Bennett, Matthew R.; Josić, Krešimir; Ott, William

    2014-05-01

    Delay is an important and ubiquitous aspect of many biochemical processes. For example, delay plays a central role in the dynamics of genetic regulatory networks as it stems from the sequential assembly of first mRNA and then protein. Genetic regulatory networks are therefore frequently modeled as stochastic birth-death processes with delay. Here, we examine the relationship between delay birth-death processes and their appropriate approximating delay chemical Langevin equations. We prove a quantitative bound on the error between the pathwise realizations of these two processes. Our results hold for both fixed delay and distributed delay. Simulations demonstrate that the delay chemical Langevin approximation is accurate even at moderate system sizes. It captures dynamical features such as the oscillatory behavior in negative feedback circuits, cross-correlations between nodes in a network, and spatial and temporal information in two commonly studied motifs of metastability in biochemical systems. Overall, these results provide a foundation for using delay stochastic differential equations to approximate the dynamics of birth-death processes with delay.

  1. Modeling delay in genetic networks: from delay birth-death processes to delay stochastic differential equations.

    PubMed

    Gupta, Chinmaya; López, José Manuel; Azencott, Robert; Bennett, Matthew R; Josić, Krešimir; Ott, William

    2014-05-28

    Delay is an important and ubiquitous aspect of many biochemical processes. For example, delay plays a central role in the dynamics of genetic regulatory networks as it stems from the sequential assembly of first mRNA and then protein. Genetic regulatory networks are therefore frequently modeled as stochastic birth-death processes with delay. Here, we examine the relationship between delay birth-death processes and their appropriate approximating delay chemical Langevin equations. We prove a quantitative bound on the error between the pathwise realizations of these two processes. Our results hold for both fixed delay and distributed delay. Simulations demonstrate that the delay chemical Langevin approximation is accurate even at moderate system sizes. It captures dynamical features such as the oscillatory behavior in negative feedback circuits, cross-correlations between nodes in a network, and spatial and temporal information in two commonly studied motifs of metastability in biochemical systems. Overall, these results provide a foundation for using delay stochastic differential equations to approximate the dynamics of birth-death processes with delay.

  2. Spatiotemporal pattern of neuronal injury induced by DFP in rats: A model for delayed neuronal cell death following acute OP intoxication

    SciTech Connect

    Li Yonggang; Lein, Pamela J.; Liu Cuimei; Bruun, Donald A.; Tewolde, Teclemichael; Ford, Gregory; Ford, Byron D.

    2011-06-15

    Organophosphate (OP) neurotoxins cause acute cholinergic toxicity and seizures resulting in delayed brain damage and persistent neurological symptoms. Testing novel strategies for protecting against delayed effects of acute OP intoxication has been hampered by the lack of appropriate animal models. In this study, we characterize the spatiotemporal pattern of cellular injury after acute intoxication with the OP diisopropylfluorophosphate (DFP). Adult male Sprague-Dawley rats received pyridostigmine (0.1 mg/kg, im) and atropine methylnitrate (20 mg/kg, im) prior to DFP (9 mg/kg, ip) administration. All DFP-treated animals exhibited moderate to severe seizures within minutes after DFP injection but survived up to 72 h. AChE activity was significantly depressed in the cortex, hippocampus, subcortical brain tissue and cerebellum at 1 h post-DFP injection and this inhibition persisted for up to 72 h. Analysis of neuronal injury by Fluoro-Jade B (FJB) labeling revealed delayed neuronal cell death in the hippocampus, cortex, amygdala and thalamus, but not the cerebellum, starting at 4 h and persisting until 72 h after DFP treatment, although temporal profiles varied between brain regions. At 24 h post-DFP injection, the pattern of FJB labeling corresponded to TUNEL staining in most brain regions, and FJB-positive cells displayed reduced NeuN immunoreactivity but were not immunopositive for astrocytic (GFAP), oligodendroglial (O4) or macrophage/microglial (ED1) markers, demonstrating that DFP causes a region-specific delayed neuronal injury mediated in part by apoptosis. These findings indicate the feasibility of this model for testing neuroprotective strategies, and provide insight regarding therapeutic windows for effective pharmacological intervention following acute OP intoxication. - Research Highlights: > DFP induced neuronal FJB labeling starting at 4-8 h after treatment > The pattern of DFP-induced FJB labeling closely corresponded to TUNEL staining > FJB

  3. Carbon monoxide-induced delayed amnesia, delayed neuronal death and change in acetylcholine concentration in mice

    SciTech Connect

    Nabeshima, T.; Katoh, A.; Ishimaru, H.; Yoneda, Y.; Ogita, K.; Murase, K.; Ohtsuka, H.; Inari, K.; Fukuta, T.; Kameyama, T. )

    1991-01-01

    We investigated the interrelationship of delayed amnesia, delayed neuronal death and changes in acetylcholine concentration induced by carbon monoxide (CO)-exposure in mice. In the test for retention of the passive avoidance task, amnesia was observed 5 and 7 days after CO-exposure when the mice were exposed to CO 1 day after training; in the case when the mice were exposed to CO 5 and 7 days before training, amnesia was also observed in a retention test given 1 day after training. The number of pyramidal cells in the hippocampal CA1 subfield was lower than that of the control 3, 5 and 7 days after CO-exposure. But the neurodegeneration in the parietal cortex, area 1, was not observed until 7 days after CO-exposure. The findings indicated that the amnesia and the neuronal death were produced after a delay when the mice were exposed to CO. In addition, the delayed amnesia was closely related to the delayed neuronal death in the hippocampal CA1 subfield. Moreover, (3H)glutamate and (3H)glycine binding sites did not change after CO-exposure but, 7 days after CO-exposure, the concentration of acetylcholine and the binding of (3H)quinuclidinyl benzilate in the frontal cortex and the striatum were found to have significantly changed, but those in the hippocampus did not show significant change. Therefore, we suggest that delayed amnesia induced by CO-exposure may result from delayed neuronal death in the hippocampal CA1 subfield and dysfunction in the acetylcholinergic neurons, in the frontal cortex, the striatum and/or the hippocampus.

  4. Programmed cell death

    SciTech Connect

    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.

  5. Delay and death-thought accessibility: a meta-analysis.

    PubMed

    Steinman, Christopher T; Updegraff, John A

    2015-12-01

    The dual-process component of Terror Management Theory (TMT) proposes that different types of threats lead to increases in death-thought accessibility (DTA) after different delay intervals. Experimental studies of terror management threats' effect on DTA were collected and coded for their use of explicitly death-related (vs. not explicitly death-related) threats, and for their use of delay and task-switching during the delay. Results reveal that studies using death-related threats achieved larger DTA effect-sizes when they included more task-switching or a longer delay between the threat and the DTA measurement. In contrast, studies using threats that were not explicitly death-related achieved smaller DTA effect-sizes when they included more task-switching between the threat and the DTA measurement. These findings provide partial support for the dual-process component's predictions regarding delay and DTA. Limitations and future directions are discussed. PMID:26443599

  6. Delay and death-thought accessibility: a meta-analysis.

    PubMed

    Steinman, Christopher T; Updegraff, John A

    2015-12-01

    The dual-process component of Terror Management Theory (TMT) proposes that different types of threats lead to increases in death-thought accessibility (DTA) after different delay intervals. Experimental studies of terror management threats' effect on DTA were collected and coded for their use of explicitly death-related (vs. not explicitly death-related) threats, and for their use of delay and task-switching during the delay. Results reveal that studies using death-related threats achieved larger DTA effect-sizes when they included more task-switching or a longer delay between the threat and the DTA measurement. In contrast, studies using threats that were not explicitly death-related achieved smaller DTA effect-sizes when they included more task-switching between the threat and the DTA measurement. These findings provide partial support for the dual-process component's predictions regarding delay and DTA. Limitations and future directions are discussed.

  7. Autophagic cell death exists

    PubMed Central

    Clarke, Peter G.H.; Puyal, Julien

    2012-01-01

    The term autophagic cell death (ACD) initially referred to cell death with greatly enhanced autophagy, but is increasingly used to imply a death-mediating role of autophagy, as shown by a protective effect of autophagy inhibition. In addition, many authors require that autophagic cell death must not involve apoptosis or necrosis. Adopting these new and restrictive criteria, and emphasizing their own failure to protect human osteosarcoma cells by autophagy inhibition, the authors of a recent Editor’s Corner article in this journal argued for the extreme rarity or nonexistence of autophagic cell death. We here maintain that, even with the more stringent recent criteria, autophagic cell death exists in several situations, some of which were ignored by the Editor’s Corner authors. We reject their additional criterion that the autophagy in ACD must be the agent of ultimate cell dismantlement. And we argue that rapidly dividing mammalian cells such as cancer cells are not the most likely situation for finding pure ACD. PMID:22652592

  8. Classification of cell death

    PubMed Central

    Kroemer, G; Galluzzi, L; Vandenabeele, P; Abrams, J; Alnemri, ES; Baehrecke, EH; Blagosklonny, MV; El-Deiry, WS; Golstein, P; Green, DR; Hengartner, M; Knight, RA; Kumar, S; Lipton, SA; Malorni, W; Nuñez, G; Peter, ME; Tschopp, J; Yuan, J; Piacentini, M; Zhivotovsky, B; Melino, G

    2009-01-01

    Different types of cell death are often defined by morphological criteria, without a clear reference to precise biochemical mechanisms. The Nomenclature Committee on Cell Death (NCCD) proposes unified criteria for the definition of cell death and of its different morphologies, while formulating several caveats against the misuse of words and concepts that slow down progress in the area of cell death research. Authors, reviewers and editors of scientific periodicals are invited to abandon expressions like ‘percentage apoptosis’ and to replace them with more accurate descriptions of the biochemical and cellular parameters that are actually measured. Moreover, at the present stage, it should be accepted that caspase-independent mechanisms can cooperate with (or substitute for) caspases in the execution of lethal signaling pathways and that ‘autophagic cell death’ is a type of cell death occurring together with (but not necessarily by) autophagic vacuolization. This study details the 2009 recommendations of the NCCD on the use of cell death-related terminology including ‘entosis’, ‘mitotic catastrophe’, ‘necrosis’, ‘necroptosis’ and ‘pyroptosis’. PMID:18846107

  9. [Effect of hypertonic saline solution on delayed neuronal death].

    PubMed

    Hamaguchi, S; Ogata, H; Masawa, N

    1994-04-01

    This experiment was performed to investigate whether hypertonic saline has a preventive effect on delayed neuronal death in the CA1 subfield of the hippocampus. Twenty gerbils were used, and after being anesthetized by inhalation of 1% halothane, both common carotid arteries were occluded for 2.5 min. The animals were injected intravenously with 2 ml/kg of 10% NaCl immediately after reperfusion, and 2 ml/kg of physiological saline solution was used in the same manner in a control group. Five days later, histopathological changes in the CA1 subfield were observed by staining with hematoxylin-eosin and examining sections of the brain under a light microscope. Degenerative or necrotic pyramidal cells exhibited cell shrinkage, nuclear pyknosis, dark staining of the cytoplasm vacuolation and disappearance of the radial striated zone. The pyramidal cell degeneration rate in a 1 mm length of CA1 subfield was 95.6 +/- 1.6% in the ischemia-reperfusion-saline group and 7.1 +/- 3.0% in ischemia-reperfusion-hypertonic saline group, and the difference was statistically significant. This study verified that hypertonic saline prevented delayed neuronal death in the CA1 subfield of hippocampal area after ischemia-reperfusion.

  10. Malonate induces cell death via mitochondrial potential collapse and delayed swelling through an ROS-dependent pathway

    PubMed Central

    Fernandez-Gomez, Francisco J; Galindo, Maria F; Gómez-Lázaro, Maria; Yuste, Victor J; Comella, Joan X; Aguirre, Norberto; Jordán, Joaquín

    2005-01-01

    Herein we study the effects of the mitochondrial complex II inhibitor malonate on its primary target, the mitochondrion. Malonate induces mitochondrial potential collapse, mitochondrial swelling, cytochrome c (Cyt c) release and depletes glutathione (GSH) and nicotinamide adenine dinucleotide coenzyme (NAD(P)H) stores in brain-isolated mitochondria. Although, mitochondrial potential collapse was almost immediate after malonate addition, mitochondrial swelling was not evident before 15 min of drug presence. This latter effect was blocked by cyclosporin A (CSA), Ruthenium Red (RR), magnesium, catalase, GSH and vitamin E. Malonate added to SH-SY5Y cell cultures produced a marked loss of cell viability together with the release of Cyt c and depletion of GSH and NAD(P)H concentrations. All these effects were not apparent in SH-SY5Y cells overexpressing Bcl-xL. When GSH concentrations were lowered with buthionine sulphoximine, cytoprotection afforded by Bcl-xL overexpression was not evident anymore. Taken together, all these data suggest that malonate causes a rapid mitochondrial potential collapse and reactive oxygen species production that overwhelms mitochondrial antioxidant capacity and leads to mitochondrial swelling. Further permeability transition pore opening and the subsequent release of proapoptotic factors such as Cyt c could therefore be, at least in part, responsible for malonate-induced toxicity. PMID:15655518

  11. Heme Oxygenase-1 Delays Gibberellin-Induced Programmed Cell Death of Rice Aleurone Layers Subjected to Drought Stress by Interacting with Nitric Oxide

    PubMed Central

    Wu, Huangming; Zheng, Yan; Liu, Jing; Zhang, Heting; Chen, Huiping

    2016-01-01

    Cereal aleurone layers undergo a gibberellin (GA)-regulated process of programmed cell death (PCD) following germination. Heme oxygenase-1 (HO-1) is known as a rate-liming enzyme in the degradation of heme to biliverdin IXα, carbon monoxide (CO), and free iron ions (Fe2+). It is a critical component in plant development and adaptation to environment stresses. Our previous studies confirmed that HO-1 inducer hematin (Ht) promotes the germination of rice seeds in drought (20% polyethylene glycol-6000, PEG) conditions, but the corresponding effects of HO-1 on the alleviation of germination-triggered PCD in GA-treated rice aleurone layers remain unknown. The present study has determined that GA co-treated with PEG results in lower HO-1 transcript levels and HO activity, which in turn results in the development of vacuoles in aleurone cells, followed by PCD. The pharmacology approach illustrated that up- or down-regulated HO-1 gene expression and HO activity delayed or accelerated GA-induced PCD. Furthermore, the application of the HO-1 inducer Ht and nitric oxide (NO) donor sodium nitroprusside (SNP) not only activated HO-1 gene expression, HO activity, and endogenous NO content, but also blocked GA-induced rapid vacuolation and accelerated aleurone layers PCD under drought stress. However, both HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX) and NO scavenger 2-(4-carboxyphenyl0-4, 4,5,5-tetramethylimidazoline-l-oxyl-3-oxide potassium salt (cPTIO) reserved the effects of Ht and SNP on rice aleurone layer PCD under drought stress by down-regulating endogenous HO-1 and NO, respectively. The inducible effects of Ht and SNP on HO-1 gene expression, HO activity, and NO content were blocked by cPTIO. Together, these results clearly suggest that HO-1 is involved in the alleviation of GA-induced PCD of drought-triggered rice aleurone layers by associating with NO. PMID:26834769

  12. Heme Oxygenase-1 Delays Gibberellin-Induced Programmed Cell Death of Rice Aleurone Layers Subjected to Drought Stress by Interacting with Nitric Oxide.

    PubMed

    Wu, Huangming; Zheng, Yan; Liu, Jing; Zhang, Heting; Chen, Huiping

    2015-01-01

    Cereal aleurone layers undergo a gibberellin (GA)-regulated process of programmed cell death (PCD) following germination. Heme oxygenase-1 (HO-1) is known as a rate-liming enzyme in the degradation of heme to biliverdin IXα, carbon monoxide (CO), and free iron ions (Fe(2+)). It is a critical component in plant development and adaptation to environment stresses. Our previous studies confirmed that HO-1 inducer hematin (Ht) promotes the germination of rice seeds in drought (20% polyethylene glycol-6000, PEG) conditions, but the corresponding effects of HO-1 on the alleviation of germination-triggered PCD in GA-treated rice aleurone layers remain unknown. The present study has determined that GA co-treated with PEG results in lower HO-1 transcript levels and HO activity, which in turn results in the development of vacuoles in aleurone cells, followed by PCD. The pharmacology approach illustrated that up- or down-regulated HO-1 gene expression and HO activity delayed or accelerated GA-induced PCD. Furthermore, the application of the HO-1 inducer Ht and nitric oxide (NO) donor sodium nitroprusside (SNP) not only activated HO-1 gene expression, HO activity, and endogenous NO content, but also blocked GA-induced rapid vacuolation and accelerated aleurone layers PCD under drought stress. However, both HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX) and NO scavenger 2-(4-carboxyphenyl0-4, 4,5,5-tetramethylimidazoline-l-oxyl-3-oxide potassium salt (cPTIO) reserved the effects of Ht and SNP on rice aleurone layer PCD under drought stress by down-regulating endogenous HO-1 and NO, respectively. The inducible effects of Ht and SNP on HO-1 gene expression, HO activity, and NO content were blocked by cPTIO. Together, these results clearly suggest that HO-1 is involved in the alleviation of GA-induced PCD of drought-triggered rice aleurone layers by associating with NO.

  13. GSK-3β inhibition promotes cell death, apoptosis, and in vivo tumor growth delay in neuroblastoma Neuro-2A cell line.

    PubMed

    Dickey, Amy; Schleicher, Stephen; Leahy, Kathleen; Hu, Rong; Hallahan, Dennis; Thotala, Dinesh Kumar

    2011-08-01

    Neuroblastoma is the most common extracranial solid tumor of childhood. While survival rates are high for localized disease, treatment response remains poor for a subset of patients with large tumors or disseminated disease. Thus, there remains much room for improvement in treatment strategies for this disease. Using in vitro and in vivo systems, we present glycogen synthase kinase-3β (GSK-3β) inhibition as a potential mechanism to treat neuroblastoma. Using the specific GSK-3β inhibitor SB415286, we demonstrate that GSK-3β inhibition decreases the viability of Neuro-2A cells, as determined by cell proliferation assay and clonogenic survival. Moreover, we show that GSK-3β inhibition induces apoptosis in neuroblastoma cells, as determined by Annexin V staining and confirmed with DAPI staining. Using flow cytometry, we are able to demonstrate that SB415286 induces the accumulation of cells in the G2/M phase of the cell cycle. Finally, we show that these in vitro results translate into delayed tumor growth in vivo using a heterotopic tumor model in nude mice treated with SB415286. These findings suggest that GSK-3β is a potential molecular target for the treatment of neuroblastoma.

  14. Hydrogen sulfide delays GA-triggered programmed cell death in wheat aleurone layers by the modulation of glutathione homeostasis and heme oxygenase-1 expression.

    PubMed

    Xie, Yanjie; Zhang, Chen; Lai, Diwen; Sun, Ya; Samma, Muhammad Kaleem; Zhang, Jing; Shen, Wenbiao

    2014-01-15

    Hydrogen sulfide (H2S) is considered as a cellular signaling intermediate in higher plants, but corresponding molecular mechanisms and signal transduction pathways in plant biology are still limited. In the present study, a combination of pharmacological and biochemical approaches was used to study the effect of H2S on the alleviation of GA-induced programmed cell death (PCD) in wheat aleurone cells. The results showed that in contrast with the responses of ABA, GA brought about a gradual decrease of l-cysteine desulfhydrase (LCD) activity and H2S production, and thereafter PCD occurred. Exogenous H2S donor sodium hydrosulfide (NaHS) not only effectively blocked the decrease of endogenous H2S release, but also alleviated GA-triggered PCD in wheat aleurone cells. These responses were sensitive to hypotaurine (HT), a H2S scavenger, suggesting that this effect of NaHS was in an H2S-dependent fashion. Further experiment confirmed that H2S, rather than other sodium- or sulphur-containing compounds derived from the decomposing of NaHS, was attributed to the rescuing response. Importantly, the reversing effect was associated with glutathione (GSH) because the NaHS triggered increases of endogenous GSH content and the ratio of GSH/oxidized GSH (GSSG) in GA-treated layers, and the NaHS-mediated alleviation of PCD was markedly eliminated by l-buthionine-sulfoximine (BSO, a selective inhibitor of GSH biosynthesis). The inducible effect of NaHS was also ascribed to the modulation of heme oxygenase-1 (HO-1), because the specific inhibitor of HO-1 zinc protoporphyrin IX (ZnPP) significantly suppressed the NaHS-related responses. By contrast, the above inhibitory effects were reversed partially when carbon monoxide (CO) aqueous solution or bilirubin (BR), two of the by-products of HO-1, was added, respectively. NaHS-triggered HO-1 gene expression in GA-treated layers was also confirmed. Together, the above results clearly suggested that the H2S-delayed PCD in GA-treated wheat

  15. Hydrogen sulfide delays GA-triggered programmed cell death in wheat aleurone layers by the modulation of glutathione homeostasis and heme oxygenase-1 expression.

    PubMed

    Xie, Yanjie; Zhang, Chen; Lai, Diwen; Sun, Ya; Samma, Muhammad Kaleem; Zhang, Jing; Shen, Wenbiao

    2014-01-15

    Hydrogen sulfide (H2S) is considered as a cellular signaling intermediate in higher plants, but corresponding molecular mechanisms and signal transduction pathways in plant biology are still limited. In the present study, a combination of pharmacological and biochemical approaches was used to study the effect of H2S on the alleviation of GA-induced programmed cell death (PCD) in wheat aleurone cells. The results showed that in contrast with the responses of ABA, GA brought about a gradual decrease of l-cysteine desulfhydrase (LCD) activity and H2S production, and thereafter PCD occurred. Exogenous H2S donor sodium hydrosulfide (NaHS) not only effectively blocked the decrease of endogenous H2S release, but also alleviated GA-triggered PCD in wheat aleurone cells. These responses were sensitive to hypotaurine (HT), a H2S scavenger, suggesting that this effect of NaHS was in an H2S-dependent fashion. Further experiment confirmed that H2S, rather than other sodium- or sulphur-containing compounds derived from the decomposing of NaHS, was attributed to the rescuing response. Importantly, the reversing effect was associated with glutathione (GSH) because the NaHS triggered increases of endogenous GSH content and the ratio of GSH/oxidized GSH (GSSG) in GA-treated layers, and the NaHS-mediated alleviation of PCD was markedly eliminated by l-buthionine-sulfoximine (BSO, a selective inhibitor of GSH biosynthesis). The inducible effect of NaHS was also ascribed to the modulation of heme oxygenase-1 (HO-1), because the specific inhibitor of HO-1 zinc protoporphyrin IX (ZnPP) significantly suppressed the NaHS-related responses. By contrast, the above inhibitory effects were reversed partially when carbon monoxide (CO) aqueous solution or bilirubin (BR), two of the by-products of HO-1, was added, respectively. NaHS-triggered HO-1 gene expression in GA-treated layers was also confirmed. Together, the above results clearly suggested that the H2S-delayed PCD in GA-treated wheat

  16. Regulated cell death and adaptive stress responses.

    PubMed

    Galluzzi, Lorenzo; Bravo-San Pedro, José Manuel; Kepp, Oliver; Kroemer, Guido

    2016-06-01

    Eukaryotic cells react to potentially dangerous perturbations of the intracellular or extracellular microenvironment by activating rapid (transcription-independent) mechanisms that attempt to restore homeostasis. If such perturbations persist, cells may still try to cope with stress by activating delayed and robust (transcription-dependent) adaptive systems, or they may actively engage in cellular suicide. This regulated form of cell death can manifest with various morphological, biochemical and immunological correlates, and constitutes an ultimate attempt of stressed cells to maintain organismal homeostasis. Here, we dissect the general organization of adaptive cellular responses to stress, their intimate connection with regulated cell death, and how the latter operates for the preservation of organismal homeostasis.

  17. Programmed cell death in neurodevelopment.

    PubMed

    Yamaguchi, Yoshifumi; Miura, Masayuki

    2015-02-23

    Programmed cell death (PCD) is an evolutionarily conserved contributor to nervous system development. In the vertebrate peripheral nervous system, PCD is the basis of the neurotrophic theory, whereby cell death results from a surplus of neurons relative to target and competition for neurotrophic factors. In addition to stochastic cell death, PCD can be intrinsically determined by cell lineage or position and timing in both invertebrate and vertebrate central nervous systems. The underlying PCD molecular mechanisms include intrinsic transcription factor cascades and regulators of competence/susceptibility to cell death. Here, we provide a framework for understanding neural PCD from its regulation to its functions.

  18. Astrogliosis is a possible player in preventing delayed neuronal death.

    PubMed

    Jeong, Hey-Kyeong; Ji, Kyung-Min; Min, Kyoung-Jin; Choi, Insup; Choi, Dong-Joo; Jou, Ilo; Joe, Eun-Hye

    2014-04-01

    Mitigating secondary delayed neuronal injury has been a therapeutic strategy for minimizing neurological symptoms after several types of brain injury. Interestingly, secondary neuronal loss appeared to be closely related to functional loss and/or death of astrocytes. In the brain damage induced by agonists of two glutamate receptors, N-ethyl-D-aspartic acid (NMDA) and kainic acid (KA), NMDA induced neuronal death within 3 h, but did not increase further thereafter. However, in the KA-injected brain, neuronal death was not obviously detectable even at injection sites at 3 h, but extensively increased to encompass the entire hemisphere at 7 days. Brain inflammation, a possible cause of secondary neuronal damage, showed little differences between the two models. Importantly, however, astrocyte behavior was completely different. In the NMDA-injected cortex, the loss of glial fibrillary acidic protein-expressing (GFAP+) astrocytes was confined to the injection site until 7 days after the injection, and astrocytes around the damage sites showed extensive gliosis and appeared to isolate the damage sites. In contrast, in the KA-injected brain, GFAP+ astrocytes, like neurons, slowly, but progressively, disappeared across the entire hemisphere. Other markers of astrocytes, including S100β, glutamate transporter EAAT2, the potassium channel Kir4.1 and glutamine synthase, showed patterns similar to that of GFAP in both NMDA- and KA-injected cortexes. More importantly, astrocyte disappearance and/or functional loss preceded neuronal death in the KA-injected brain. Taken together, these results suggest that loss of astrocyte support to neurons may be a critical cause of delayed neuronal death in the injured brain. PMID:24802057

  19. Phagocytosis executes delayed neuronal death after focal brain ischemia.

    PubMed

    Neher, Jonas J; Emmrich, Julius V; Fricker, Michael; Mander, Palwinder K; Théry, Clotilde; Brown, Guy C

    2013-10-22

    Delayed neuronal loss and brain atrophy after cerebral ischemia contribute to stroke and dementia pathology, but the mechanisms are poorly understood. Phagocytic removal of neurons is generally assumed to be beneficial and to occur only after neuronal death. However, we report herein that inhibition of phagocytosis can prevent delayed loss and death of functional neurons after transient brain ischemia. Two phagocytic proteins, Mer receptor tyrosine kinase (MerTK) and Milk fat globule EGF-like factor 8 (MFG-E8), were transiently up-regulated by macrophages/microglia after focal brain ischemia in vivo. Strikingly, deficiency in either protein completely prevented long-term functional motor deficits after cerebral ischemia and strongly reduced brain atrophy as a result of inhibiting phagocytosis of neurons. Correspondingly, in vitro glutamate-stressed neurons reversibly exposed the "eat-me" signal phosphatidylserine, leading to their phagocytosis by microglia; this neuronal loss was prevented in the absence of microglia and reduced if microglia were genetically deficient in MerTK or MFG-E8, both of which mediate phosphatidylserine-recognition. Thus, phagocytosis of viable neurons contributes to brain pathology and, surprisingly, blocking this process is strongly beneficial. Therefore, inhibition of specific phagocytic pathways may present therapeutic targets for preventing delayed neuronal loss after transient cerebral ischemia.

  20. Oscillation death in asymmetrically delay-coupled oscillators.

    PubMed

    Zou, Wei; Tang, Yang; Li, Lixiang; Kurths, Jürgen

    2012-04-01

    Symmetrically coupled oscillators represent a limiting case for studying the dynamics of natural systems. Therefore, we here investigate the effect of coupling asymmetry on delay-induced oscillation death (OD) in coupled nonlinear oscillators. It is found that the asymmetrical coupling substantially enlarges the domain of the OD island in the parameter space. Specifically, when the intensity of asymmetry is enhanced by turning down the value of the coupling asymmetry parameter α, the OD island gradually expands along two directions of both the coupling delay and the coupling strength. The expansion behavior of the OD region is well characterized by a power law scaling, R=α(γ) with γ≈-1.19. The minimum value of the intrinsic frequency, for which OD is possible, monotonically decreases with decreasing α and saturates around a constant value in the limit of α→0. The generality of the conducive effect of coupling asymmetry is confirmed in a numerical study of two delay-coupled chaotic Rössler oscillators. Our findings shed an improved light on the understanding of dynamics in asymmetrically delay-coupled systems.

  1. Programmed cell death in protists.

    PubMed

    Deponte, Marcel

    2008-07-01

    Programmed cell death in protists does not seem to make sense at first sight. However, apoptotic markers in unicellular organisms have been observed in all but one of the six/eight major groups of eukaryotes suggesting an ancient evolutionary origin of this regulated process. This review summarizes the available data on apoptotic markers in non-opisthokonts and elucidates potential functions and evolution of programmed cell death. A newly discovered family of caspase-like proteases, the metacaspases, is considered to exert the function of caspases in unicellular organisms. Important results on metacaspases, however, showed that they cannot be always correlated to the measured proteolytic activity during protist cell death. Thus, a major challenge for apoptosis research in a variety of protists remains the identification of the molecular cell death machinery.

  2. Role of tissue plasminogen activator/plasmin cascade in delayed neuronal death after transient forebrain ischemia.

    PubMed

    Takahashi, Hiroshi; Nagai, Nobuo; Urano, Tetsumei

    We studied the possible involvement of the tissue plasminogen activator (t-PA)/plasmin system on both delayed neuronal death in the hippocampus and the associated enhancement of locomotor activity in rats, after transient forebrain ischemia induced by a four-vessel occlusion (FVO). Seven days after FVO, locomotor activity was abnormally increased and, after 10 days, pyramidal cells were degraded in the CA1 region of the hippocampus. FVO increased the t-PA antigen level and its activity in the hippocampus, which peaked at 4 h. Both the enhanced locomotor activity and the degradation of pyramidal cells were significantly suppressed by intracerebroventricular injection of aprotinin, a plasmin inhibitor, at 4 h but not during FVO. These results suggest the importance of the t-PA/plasmin cascade during the early pathological stages of delayed neuronal death in the hippocampus following transient forebrain ischemia.

  3. Caspase-independent cell deaths.

    PubMed

    Lockshin, Richard A; Zakeri, Zahra

    2002-12-01

    A very common and the best understood of the mechanisms of physiological cell death is apoptosis, resulting from the activation, through either of two primary pathways, of site-specific proteases called caspases. There are, however, many other routes to cell death, prominently including autophagy and proteasomal degradation of critical constituents of cells. These routes are frequently seen in experimental situations in which initiator or effector caspases are inhibited or blocked through genetic means, but they are also encountered during normal physiological and pathological processes. Most frequently, autophagic or proteasomal degradation is used to eliminate massive cytoplasm of very large cells, especially post-mitotic cells, and these pathways are prominent even though caspase genes, messages, and pro-enzymes are found in the cells. These forms of cell death are fully physiological and not simply a default pathway for a defective cell; and they are distinct from necrosis. We do not yet understand the extent to which the pathways are linked, what mechanisms trigger the caspase-independent deaths, and how the choices are made.

  4. Regulated cell death in AKI.

    PubMed

    Linkermann, Andreas; Chen, Guochun; Dong, Guie; Kunzendorf, Ulrich; Krautwald, Stefan; Dong, Zheng

    2014-12-01

    AKI is pathologically characterized by sublethal and lethal damage of renal tubules. Under these conditions, renal tubular cell death may occur by regulated necrosis (RN) or apoptosis. In the last two decades, tubular apoptosis has been shown in preclinical models and some clinical samples from patients with AKI. Mechanistically, apoptotic cell death in AKI may result from well described extrinsic and intrinsic pathways as well as ER stress. Central converging nodes of these pathways are mitochondria, which become fragmented and sensitized to membrane permeabilization in response to cellular stress, resulting in the release of cell death-inducing factors. Whereas apoptosis is known to be regulated, tubular necrosis was thought to occur by accident until recent work unveiled several RN subroutines, most prominently receptor-interacting protein kinase-dependent necroptosis and RN induced by mitochondrial permeability transition. Additionally, other cell death pathways, like pyroptosis and ferroptosis, may also be of pathophysiologic relevance in AKI. Combination therapy targeting multiple cell-death pathways may, therefore, provide maximal therapeutic benefits. PMID:24925726

  5. Glutathione in Cancer Cell Death

    PubMed Central

    Ortega, Angel L.; Mena, Salvador; Estrela, Jose M.

    2011-01-01

    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. PMID:24212662

  6. Cell Death in Genome Evolution

    PubMed Central

    Teng, Xinchen; Hardwick, J. Marie

    2015-01-01

    Inappropriate survival of abnormal cells underlies tumorigenesis. Most discoveries about programmed cell death have come from studying model organisms. Revisiting the experimental contexts that inspired these discoveries helps explain confounding biases that inevitably accompany such discoveries. Amending early biases has added a newcomer to the collection of cell death models. Analysis of gene-dependent death in yeast revealed the surprising influence of single gene mutations on subsequent eukaryotic genome evolution. Similar events may influence the selection for mutations during early tumorigenesis. The possibility that an early random mutation might drive the selection for a cancer driver mutation is conceivable but difficult to demonstrate. This was tested in yeast, revealing that mutation of almost any gene appears to specify the selection for a new second mutation. Some human tumors contain pairs of mutant genes homologous to co-occurring mutant genes in yeast. Here we consider how yeast again provide novel insights into tumorigenesis. PMID:25725369

  7. Pancreatic β Cell Mass Death

    PubMed Central

    Marrif, Husnia I.; Al-Sunousi, Salma I.

    2016-01-01

    Type two diabetes (T2D) is a challenging metabolic disorder for which a cure has not yet been found. Its etiology is associated with several phenomena, including significant loss of insulin-producing, beta cellcell) mass via progressive programmed cell death and disrupted cellular autophagy. In diabetes, the etiology of β cell death and the role of mitochondria are complex and involve several layers of mechanisms. Understanding the dynamics of those mechanisms could permit researchers to develop an intervention for the progressive loss of β cells. Currently, diabetes research has shifted toward rejuvenation and plasticity technology and away from the simplified approach of hormonal compensation. Diabetes research is currently challenged by questions such as how to enhance cell survival, decrease apoptosis and replenish β cell mass in diabetic patients. In this review, we discuss evidence that β cell development and mass formation are guided by specific signaling systems, particularly hormones, transcription factors, and growth factors, all of which could be manipulated to enhance mass growth. There is also strong evidence that β cells are dynamically active cells, which, under specific conditions such as obesity, can increase in size and subsequently increase insulin secretion. In certain cases of aggressive or advanced forms of T2D, β cells become markedly impaired, and the only alternatives for maintaining glucose homeostasis are through partial or complete cell grafting (the Edmonton protocol). In these cases, the harvesting of an enriched population of viable β cells is required for transplantation. This task necessitates a deep understanding of the pharmacological agents that affect β cell survival, mass, and function. The aim of this review is to initiate discussion about the important signals in pancreatic β cell development and mass formation and to highlight the process by which cell death occurs in diabetes. This review also examines the

  8. Regulated Cell Death in AKI

    PubMed Central

    Chen, Guochun; Dong, Guie; Kunzendorf, Ulrich; Krautwald, Stefan

    2014-01-01

    AKI is pathologically characterized by sublethal and lethal damage of renal tubules. Under these conditions, renal tubular cell death may occur by regulated necrosis (RN) or apoptosis. In the last two decades, tubular apoptosis has been shown in preclinical models and some clinical samples from patients with AKI. Mechanistically, apoptotic cell death in AKI may result from well described extrinsic and intrinsic pathways as well as ER stress. Central converging nodes of these pathways are mitochondria, which become fragmented and sensitized to membrane permeabilization in response to cellular stress, resulting in the release of cell death–inducing factors. Whereas apoptosis is known to be regulated, tubular necrosis was thought to occur by accident until recent work unveiled several RN subroutines, most prominently receptor-interacting protein kinase–dependent necroptosis and RN induced by mitochondrial permeability transition. Additionally, other cell death pathways, like pyroptosis and ferroptosis, may also be of pathophysiologic relevance in AKI. Combination therapy targeting multiple cell-death pathways may, therefore, provide maximal therapeutic benefits. PMID:24925726

  9. Neurodegeneration in Lurcher mice occurs via multiple cell death pathways.

    PubMed

    Doughty, M L; De Jager, P L; Korsmeyer, S J; Heintz, N

    2000-05-15

    Lurcher (Lc) is a gain-of-function mutation in the delta2 glutamate receptor (GRID2) that results in the cell-autonomous death of cerebellar Purkinje cells in heterozygous lurcher (+/Lc) mice. This in turn triggers the massive loss of afferent granule cells during the first few postnatal weeks. Evidence suggests that the death of Purkinje cells as a direct consequence of GRID2(Lc) activation and the secondary death of granule cells because of target deprivation occur by apoptosis. We have used mice carrying null mutations of both the Bax and p53 genes to examine the roles of these genes in cell loss in lurcher animals. The absence of Bax delayed Purkinje cell death in response to the GRID2(Lc) mutation and permanently rescued the secondary death of granule cells. In contrast, the p53 deletion had no effect on either cell death pathway. Our results demonstrate that target deprivation induces a Bax-dependent, p53-independent cell death response in cerebellar granule cells in vivo. In contrast, Bax plays a minor role in GRID2(Lc)-mediated Purkinje cell death.

  10. Arabidopsis ACCELERATED CELL DEATH2 modulates programmed cell death.

    PubMed

    Yao, Nan; Greenberg, Jean T

    2006-02-01

    The Arabidopsis thaliana chloroplast protein ACCELERATED CELL DEATH2 (ACD2) modulates the amount of programmed cell death (PCD) triggered by Pseudomonas syringae and protoporphyrin IX (PPIX) treatment. In vitro, ACD2 can reduce red chlorophyll catabolite, a chlorophyll derivative. We find that ACD2 shields root protoplasts that lack chlorophyll from light- and PPIX-induced PCD. Thus, chlorophyll catabolism is not obligatory for ACD2 anti-PCD function. Upon P. syringae infection, ACD2 levels and localization change in cells undergoing PCD and in their close neighbors. Thus, ACD2 shifts from being largely in chloroplasts to partitioning to chloroplasts, mitochondria, and, to a small extent, cytosol. ACD2 protects cells from PCD that requires the early mitochondrial oxidative burst. Later, the chloroplasts of dying cells generate NO, which only slightly affects cell viability. Finally, the mitochondria in dying cells have dramatically altered movements and cellular distribution. Overproduction of both ACD2 (localized to mitochondria and chloroplasts) and ascorbate peroxidase (localized to chloroplasts) greatly reduces P. syringae-induced PCD, suggesting a pro-PCD role for mitochondrial and chloroplast events. During infection, ACD2 may bind to and/or reduce PCD-inducing porphyrin-related molecules in mitochondria and possibly chloroplasts that generate reactive oxygen species, cause altered organelle behavior, and activate a cascade of PCD-inducing events.

  11. Folic acid deficiency increases delayed neuronal death, DNA damage, platelet endothelial cell adhesion molecule-1 immunoreactivity, and gliosis in the hippocampus after transient cerebral ischemia.

    PubMed

    Hwang, In Koo; Yoo, Ki-Yeon; Suh, Hong-Won; Kim, Young Sup; Kwon, Dae Young; Kwon, Young-Guen; Yoo, Jun-Hyun; Won, Moo-Ho

    2008-07-01

    Folic acid deficiency increases stroke risk. In the present study, we examined whether folic acid deficiency enhances neuronal damage and gliosis via oxidative stress in the gerbil hippocampus after transient forebrain ischemia. Animals were exposed to a folic acid-deficient diet (FAD) for 3 months and then subjected to occlusion of both common carotid arteries for 5 min. Exposure to an FAD increased plasma homocysteine levels by five- to eightfold compared with those of animals fed with a control diet (CD). In CD-treated animals, most neurons were dead in the hippocampal CA1 region 4 days after ischemia/reperfusion, whereas, in FAD-treated animals, this occurred 3 days after ischemia/reperfusion. Immunostaining for 8-hydroxy-2'-deoxyguanosine (8-OHdG) was performed to examine DNA damage in CA1 neurons in both groups after ischemia, and it was found that 8-OHdG immunoreactivity in both FAD and CD groups peaked at 12 hr after reperfusion, although the immunoreactivity in the FAD group was much greater than that in the CD group. Platelet endothelial cell adhesion molecule-1 (PECAM-1; a final mediator of neutrophil transendothelial migration) immunoreactivity in both groups increased with time after ischemia/reperfusion: Its immunoreactivity in the FAD group was much higher than that in the CD group 3 days after ischemia/reperfusion. In addition, reactive gliosis in the ischemic CA1 region increased with time after ischemia in both groups, but astrocytosis and microgliosis in the FAD group were more severe than in the CD group at all times after ischemia. Our results suggest that folic acid deficiency enhances neuronal damage induced by ischemia.

  12. Programmed cell death in aging

    PubMed Central

    Tower, John

    2015-01-01

    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. PMID:25862945

  13. Active oxygen and cell death in cereal aleurone cells.

    PubMed

    Fath, Angelika; Bethke, Paul; Beligni, Veronica; Jones, Russell

    2002-05-01

    The cereal aleurone layer is a secretory tissue whose function is regulated by gibberellic acid (GA) and abscisic acid (ABA). Aleurone cells lack functional chloroplasts, thus excluding photosynthesis as a source of active oxygen species (AOS) in cell death. Incubation of barley aleurone layers or protoplasts in GA initiated the cell death programme, but incubation in ABA delays programmed cell death (PCD). Light, especially blue and UV-A light, and H(2)O(2) accelerate PCD of GA-treated aleurone cells, but ABA-treated aleurone cells are refractory to light and H(2)O(2) and are not killed. It was shown that light elevated intracellular H(2)O(2), and that the rise in H(2)O(2) was greater in GA-treated cells compared to cells in ABA. Experiments with antioxidants show that PCD in aleurone is probably regulated by AOS. The sensitivity of GA-treated aleurone to light and H(2)O(2) is a result of lowered amounts of enzymes that metabolize AOS. mRNAs encoding catalase, ascorbate peroxidase and superoxide dismutase are all reduced during 6-18 h of incubation in GA, but these mRNAs were present in higher amounts in cells incubated in ABA. The amounts of protein and enzyme activities encoded by these mRNAs were also dramatically reduced in GA-treated cells. Aleurone cells store and metabolize neutral lipids via the glyoxylate cycle in response to GA, and glyoxysomes are one potential source of AOS in the GA-treated cells. Mitochondria are another potential source of AOS in GA-treated cells. AOS generated by these organelles bring about membrane rupture and cell death.

  14. Cell death in the nervous system

    PubMed Central

    Bredesen, Dale E.; Rao, Rammohan V.; Mehlen, Patrick

    2014-01-01

    Neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease trigger neuronal cell death through endogenous suicide pathways. Surprisingly, although the cell death itself may occur relatively late in the course of the degenerative process, the mediators of the underlying cell-death pathways have shown promise as potential therapeutic targets. PMID:17051206

  15. Pathogen Tactics to Manipulate Plant Cell Death.

    PubMed

    Mukhtar, M Shahid; McCormack, Maggie E; Argueso, Cristiana T; Pajerowska-Mukhtar, Karolina M

    2016-07-11

    Cell death is a vital process for multicellular organisms. Programmed cell death (PCD) functions in a variety of processes including growth, development, and immune responses for homeostasis maintenance. In particular, plants and animals utilize PCD to control pathogen invasion and infected cell populations. Despite some similarity, there are a number of key differences between how these organisms initiate and regulate cell death. In contrast to animals, plants are sessile, lack a circulatory system, and have additional cellular structures, including cell walls and chloroplasts. Plant cells have the autonomous ability to induce localized cell death using conserved eukaryotic pathways as well as unique plant-specific pathways. Thus, in order to successfully infect host cells, pathogens must subvert immune responses and avoid detection to prevent PCD and allow infection. Here we discuss the roles of cell death in plant immune responses and the tactics pathogens utilize to avert cell death. PMID:27404256

  16. How cell death shapes cancer

    PubMed Central

    Labi, V; Erlacher, M

    2015-01-01

    Apoptosis has been established as a mechanism of anti-cancer defense. Members of the BCL-2 family are critical mediators of apoptotic cell death in health and disease, often found to be deregulated in cancer and believed to lead to the survival of malignant clones. However, over the years, a number of studies pointed out that a model in which cell death resistance unambiguously acts as a barrier against malignant disease might be too simple. This is based on paradoxical observations made in tumor patients as well as mouse models indicating that apoptosis can indeed drive tumor formation, at least under certain circumstances. One possible explanation for this phenomenon is that apoptosis can promote proliferation critically needed to compensate for cell loss, for example, upon therapy, and to restore tissue homeostasis. However, this, at the same time, can promote tumor development by allowing expansion of selected clones. Usually, tissue resident stem/progenitor cells are a major source for repopulation, some of them potentially carrying (age-, injury- or therapy-induced) genetic aberrations deleterious for the host. Thereby, apoptosis might drive genomic instability by facilitating the emergence of pathologic clones during phases of proliferation and subsequent replication stress-associated DNA damage. Tumorigenesis initiated by repeated cell attrition and repopulation, as confirmed in different genetic models, has parallels in human cancers, exemplified in therapy-induced secondary malignancies and myelodysplastic syndromes in patients with congenital bone marrow failure syndromes. Here, we aim to review evidence in support of the oncogenic role of stress-induced apoptosis. PMID:25741600

  17. Emergence of amplitude death scenario in a network of oscillators under repulsive delay interaction

    NASA Astrophysics Data System (ADS)

    Bera, Bidesh K.; Hens, Chittaranjan; Ghosh, Dibakar

    2016-07-01

    We report the existence of amplitude death in a network of identical oscillators under repulsive mean coupling. Amplitude death appears in a globally coupled network of identical oscillators with instantaneous repulsive mean coupling only when the number of oscillators is more than two. We further investigate that, amplitude death may emerge even in two coupled oscillators as well as network of oscillators if we introduce delay time in the repulsive mean coupling. We have analytically derived the region of amplitude death island and find out how strength of delay controls the death regime in two coupled or a large network of coupled oscillators. We have verified our results on network of delayed Mackey-Glass systems where parameters are set in hyperchaotic regime. We have also tested our coupling approach in two paradigmatic limit cycle oscillators: Stuart-Landau and Van der Pol oscillators.

  18. A necrotic cell death model in a protist.

    PubMed

    Laporte, C; Kosta, A; Klein, G; Aubry, L; Lam, D; Tresse, E; Luciani, M F; Golstein, P

    2007-02-01

    While necrotic cell death is attracting considerable interest, its molecular bases are still poorly understood. Investigations in simple biological models, taken for instance outside the animal kingdom, may benefit from less interference from other cell death mechanisms and from better experimental accessibility, while providing phylogenetic information. Can necrotic cell death occur outside the animal kingdom? In the protist Dictyostelium, developmental stimuli induced in an autophagy mutant a stereotyped sequence of events characteristic of necrotic cell death. This sequence included swift mitochondrial uncoupling with mitochondrial 2',7'-dichlorofluorescein diacetate fluorescence, ATP depletion and increased oxygen consumption. This was followed by perinuclear clustering of dilated mitochondria. Rapid plasma membrane rupture then occurred, which was evidenced by time-lapse videos and quantified by FACS. Of additional interest, developmental stimuli and classical mitochondrial uncouplers triggered a similar sequence of events, and exogenous glucose delayed plasma membrane rupture in a nonglycolytic manner. The occurrence of necrotic cell death in the protist Dictyostelium (1) provides a very favorable model for further study of this type of cell death, and (2) strongly suggests that the mechanism underlying necrotic cell death was present in an ancestor common to the Amoebozoa protists and to animals and has been conserved in evolution.

  19. Cell death: a dynamic response concept.

    PubMed

    Loos, Benjamin; Engelbrecht, Anna-Mart

    2009-07-01

    Autophagy, apoptosis and necrosis have previously been described as distinct static processes that induce and execute cell death. Due to an increased use of novel techniques in mapping cellular death-techniques which allow for reporting of real-time data-the existence of "grey zones" between cell death modes and the existence of the "point of no return" within these have been revealed. This revelation demands the integration of new concepts in describing the cellular death process. Furthermore, since the contribution of autophagy in cell death or cell survival is still poorly understood, it is important to accurately describe its function within the dynamic framework of cell death. In this review cell death is viewed as a dynamic and integrative cellular response to ensure the highest likelihood of self-preservation. Suggestions are offered for conceptualizing cell death modes and their morphological features, both individually and in relation to one another. It addresses the need for distinguishing between dying cells and dead cells so as to better locate and control the onset of cell death. Most importantly, the fundamental role of autophagy, autophagic flux, and the effects of the intracellular metabolic environment on the kinetics of the cell death modes are stressed. It also contextualizes the kinetic dimension of cell death as a process and aims to contribute towards a better understanding of autophagy as a key mechanism within this process. Understanding the dynamic nature of the cell death process and autophagy's central role can reveal new insight for therapeutic intervention in preventing cell death.

  20. Molecular definitions of cell death subroutines: recommendations of the Nomenclature Committee on Cell Death 2012

    PubMed Central

    Galluzzi, L; Vitale, I; Abrams, J M; Alnemri, E S; Baehrecke, E H; Blagosklonny, M V; Dawson, T M; Dawson, V L; El-Deiry, W S; Fulda, S; Gottlieb, E; Green, D R; Hengartner, M O; Kepp, O; Knight, R A; Kumar, S; Lipton, S A; Lu, X; Madeo, F; Malorni, W; Mehlen, P; Nuñez, G; Peter, M E; Piacentini, M; Rubinsztein, D C; Shi, Y; Simon, H-U; Vandenabeele, P; White, E; Yuan, J; Zhivotovsky, B; Melino, G; Kroemer, G

    2012-01-01

    In 2009, the Nomenclature Committee on Cell Death (NCCD) proposed a set of recommendations for the definition of distinct cell death morphologies and for the appropriate use of cell death-related terminology, including ‘apoptosis', ‘necrosis' and ‘mitotic catastrophe'. In view of the substantial progress in the biochemical and genetic exploration of cell death, time has come to switch from morphological to molecular definitions of cell death modalities. Here we propose a functional classification of cell death subroutines that applies to both in vitro and in vivo settings and includes extrinsic apoptosis, caspase-dependent or -independent intrinsic apoptosis, regulated necrosis, autophagic cell death and mitotic catastrophe. Moreover, we discuss the utility of expressions indicating additional cell death modalities. On the basis of the new, revised NCCD classification, cell death subroutines are defined by a series of precise, measurable biochemical features. PMID:21760595

  1. Programmed Cell Death During Caenorhabditis elegans Development.

    PubMed

    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. PMID:27516615

  2. Praying until Death: Apostolicism, Delays and Maternal Mortality in Zimbabwe.

    PubMed

    Munyaradzi Kenneth, Dodzo; Marvellous, Mhloyi; Stanzia, Moyo; Memory, Dodzo-Masawi

    2016-01-01

    Religion affects people's daily lives by solving social problems, although it creates others. Female sexual and reproductive health are among the issues most affected by religion. Apostolic sect members in Zimbabwe have been associated with higher maternal mortality. We explored apostolic beliefs and practices on maternal health using 15 key informant interviews in 5 purposively selected districts of Zimbabwe. Results show that apostolicism promotes high fertility, early marriage, non-use of contraceptives and low or non-use of hospital care. It causes delays in recognizing danger signs, deciding to seek care, reaching and receiving appropriate health care. The existence of a customized spiritual maternal health system demonstrates a huge desire for positive maternal health outcomes among apostolics. We conclude that apostolic beliefs and practices exacerbate delays between onset of maternal complications and receiving help, thus increasing maternal risk. We recommend complementary and adaptive approaches that address the maternal health needs of apostolics in a religiously sensitive manner. PMID:27509018

  3. Praying until Death: Apostolicism, Delays and Maternal Mortality in Zimbabwe

    PubMed Central

    2016-01-01

    Religion affects people’s daily lives by solving social problems, although it creates others. Female sexual and reproductive health are among the issues most affected by religion. Apostolic sect members in Zimbabwe have been associated with higher maternal mortality. We explored apostolic beliefs and practices on maternal health using 15 key informant interviews in 5 purposively selected districts of Zimbabwe. Results show that apostolicism promotes high fertility, early marriage, non-use of contraceptives and low or non-use of hospital care. It causes delays in recognizing danger signs, deciding to seek care, reaching and receiving appropriate health care. The existence of a customized spiritual maternal health system demonstrates a huge desire for positive maternal health outcomes among apostolics. We conclude that apostolic beliefs and practices exacerbate delays between onset of maternal complications and receiving help, thus increasing maternal risk. We recommend complementary and adaptive approaches that address the maternal health needs of apostolics in a religiously sensitive manner. PMID:27509018

  4. Cell biology. Metabolic control of cell death.

    PubMed

    Green, Douglas R; Galluzzi, Lorenzo; Kroemer, Guido

    2014-09-19

    Beyond their contribution to basic metabolism, the major cellular organelles, in particular mitochondria, can determine whether cells respond to stress in an adaptive or suicidal manner. Thus, mitochondria can continuously adapt their shape to changing bioenergetic demands as they are subjected to quality control by autophagy, or they can undergo a lethal permeabilization process that initiates apoptosis. Along similar lines, multiple proteins involved in metabolic circuitries, including oxidative phosphorylation and transport of metabolites across membranes, may participate in the regulated or catastrophic dismantling of organelles. Many factors that were initially characterized as cell death regulators are now known to physically or functionally interact with metabolic enzymes. Thus, several metabolic cues regulate the propensity of cells to activate self-destructive programs, in part by acting on nutrient sensors. This suggests the existence of "metabolic checkpoints" that dictate cell fate in response to metabolic fluctuations. Here, we discuss recent insights into the intersection between metabolism and cell death regulation that have major implications for the comprehension and manipulation of unwarranted cell loss.

  5. Chemotherapeutic Approaches for Targeting Cell Death Pathways

    PubMed Central

    Ricci, M. Stacey; Zong, Wei-Xing

    2011-01-01

    For several decades, apoptosis has taken center stage as the principal mechanism of programmed cell death in mammalian tissues. It also has been increasingly noted that conventional chemotherapeutic agents not only elicit apoptosis but other forms of nonapoptotic death such as necrosis, autophagy, mitotic catastrophe, and senescence. This review presents background on the signaling pathways involved in the different cell death outcomes. A re-examination of what we know about chemotherapy-induced death is vitally important in light of new understanding of nonapoptotic cell death signaling pathways. If we can precisely activate or inhibit molecules that mediate the diversity of cell death outcomes, perhaps we can succeed in more effective and less toxic chemotherapeutic regimens. PMID:16614230

  6. Death receptor pathways mediate targeted and non-targeted effects of ionizing radiations in breast cancer cells

    PubMed Central

    Luce, Audrey; Courtin, Aurélie; Levalois, Céline; Altmeyer-Morel, Sandrine; Romeo, Paul-Henri; Lebeau, Jérôme

    2009-01-01

    Delayed cell death by mitotic catastrophe is a frequent mode of solid tumor cell death after γ-irradiation, a widely used treatment of cancer. Whereas the mechanisms that underlie the early γ-irradiation-induced cell death are well documented, those that drive the delayed cell death are largely unknown. Here we show that the Fas, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and tumor necrosis factor (TNF)-α death receptor pathways mediate the delayed cell death observed after γ-irradiation of breast cancer cells. Early after irradiation, we observe the increased expression of Fas, TRAIL-R and TNF-R that first sensitizes cells to apoptosis. Later, the increased expression of FasL, TRAIL and TNF-α permit the apoptosis engagement linked to mitotic catastrophe. Treatments with TNF-α, TRAIL or anti-Fas antibody, early after radiation exposure, induce apoptosis, whereas the neutralization of the three death receptors pathways impairs the delayed cell death. We also show for the first time that irradiated breast cancer cells excrete soluble forms of the three ligands that can induce the death of sensitive bystander cells. Overall, these results define the molecular basis of the delayed cell death of irradiated cancer cells and identify the death receptors pathways as crucial actors in apoptosis induced by targeted as well as non-targeted effects of ionizing radiation. PMID:19126655

  7. Spontaneous cell death in the chorion laeve.

    PubMed

    Parmley, T H

    1990-06-01

    The granulosa cells of the dominant follicle grow, differentiate, and die in a roughly predictable amount of time. Because the simultaneous death of this population of cells results in menstruation, one may say that the life span of this population of cells "times" the menstrual cycle. Metamorphosis in amphibians and morphogenesis in several vertebrates are other examples of developmental milestones that are "timed" by the life span of specific cell populations. In all these examples, cell death is associated with a specific histology, apoptosis. Apoptosis characterizes the cell death that produces the progressive disappearance of the trophoblast in the chorion laeve as term is approached. Therefore, the histology of trophoblastic death in the near-term chorion laeve corresponds to that of populations of cells with life spans that "time" developmental events. The trophoblastic cell population of the chorion laeve is prematurely destroyed by infiltrating maternal leukocytes in cases of chorioamnionitis.

  8. BOLD delay times using group delay in sickle cell disease

    NASA Astrophysics Data System (ADS)

    Coloigner, Julie; Vu, Chau; Bush, Adam; Borzage, Matt; Rajagopalan, Vidya; Lepore, Natasha; Wood, John

    2016-03-01

    Sickle cell disease (SCD) is an inherited blood disorder that effects red blood cells, which can lead to vasoocclusion, ischemia and infarct. This disease often results in neurological damage and strokes, leading to morbidity and mortality. Functional Magnetic Resonance Imaging (fMRI) is a non-invasive technique for measuring and mapping the brain activity. Blood Oxygenation Level-Dependent (BOLD) signals contain also information about the neurovascular coupling, vascular reactivity, oxygenation and blood propagation. Temporal relationship between BOLD fluctuations in different parts of the brain provides also a mean to investigate the blood delay information. We used the induced desaturation as a label to profile transit times through different brain areas, reflecting oxygen utilization of tissue. In this study, we aimed to compare blood flow propagation delay times between these patients and healthy subjects in areas vascularized by anterior, middle and posterior cerebral arteries. In a group comparison analysis with control subjects, BOLD changes in these areas were found to be almost simultaneous and shorter in the SCD patients, because of their increased brain blood flow. Secondly, the analysis of a patient with a stenosis on the anterior cerebral artery indicated that signal of the area vascularized by this artery lagged the MCA signal. These findings suggest that sickle cell disease causes blood propagation modifications, and that these changes could be used as a biomarker of vascular damage.

  9. Joint aging and chondrocyte cell death

    PubMed Central

    Grogan, Shawn P; D’Lima, Darryl D

    2010-01-01

    Articular cartilage extracellular matrix and cell function change with age and are considered to be the most important factors in the development and progression of osteoarthritis. The multifaceted nature of joint disease indicates that the contribution of cell death can be an important factor at early and late stages of osteoarthritis. Therefore, the pharmacologic inhibition of cell death is likely to be clinically valuable at any stage of the disease. In this article, we will discuss the close association between diverse changes in cartilage aging, how altered conditions influence chondrocyte death, and the implications of preventing cell loss to retard osteoarthritis progression and preserve tissue homeostasis. PMID:20671988

  10. Autophagy and cell death in model organisms.

    PubMed

    Kourtis, N; Tavernarakis, N

    2009-01-01

    Autophagy evolved in unicellular eukaryotes as a means for surviving nutrient stress. During the course of evolution, as multicellular organisms developed specialized cell types and complex intracellular signalling networks, autophagy has been summoned to serve additional cellular functions. Numerous recent studies indicate that apart from its pro-survival role under nutrient limitation, autophagy also participates in cell death. However, the precise role of this catabolic process in dying cells is not fully understood. Although in certain situations autophagy has a protective function, in other types of cell death it actually contributes to cellular destruction. Simple model organisms ranging from the unicellular Saccharomyces cerevisiae to the soil amoeba Dictyostelium discoideum and the metazoans Caenorhabditis elegans and Drosophila melanogaster provide clearly defined cell death paradigms that can be used to dissect the involvement of autophagy in cell death, at the molecular level. In this review, we survey current research in simple organisms, linking autophagy to cell death and discuss the complex interplay between autophagy, cell survival and cell death. PMID:19079286

  11. Entosis and Related Forms of Cell Death within Cells.

    PubMed

    Wang, Y; Wang, X-D

    2015-01-01

    By eliminating the unneeded or mutant cells, programmed cell death actively participates in a wide range of biological processes from embryonic development to homeostasis maintenance in adult. Continuing efforts have identified multiple cell death pathways, with apoptosis, necrosis and autophage the mostly studied. Recently a unique cell death pathway called "cell-in-cell death" has been defined. Unlike traditional cell death pathways, cell-in-cell death, characterized by cell death within another cell, is triggered by the invasion of one cell into its neighbor and executed by either lysosome-dependent degradation or caspase-dependent apoptosis. With remarkable progresses on cell-in-cell over past few years, multiple mechanisms, including entosis, cannibalism and emperitosis, are found to be responsible for cell-in-cell death. Some key questions, such as specific biochemical markers to distinguish precisely the properties of different cell-in-cell structures and the physiological and pathological relevance, remain to be addressed. In light of this situation and a surge of interests, leading scientists in this field intend to share with readers current research progresses on cell-in-cell structures from different model systems through this special edition on cell-in-cell. The mechanistic advances will be highlighted while the future researches be speculated. PMID:26511710

  12. Cell probing by delayed luminescence

    NASA Astrophysics Data System (ADS)

    Musumeci, Francesco; Ballerini, Monica; Baroni, Giuliana; Costato, Michele; Ferraro, Lorenzo; Milani, Marziale; Scordino, Agata; Triglia, Antonio

    1999-05-01

    Delayed luminescence (D.L.) is a measure that provides important information on biological systems fields, structures and activities, by counting impinging and emitted photons. Many recent experimental works have shown the existence of a close connection, sometimes analytically expressed between the biological state of the system and D.L. parameters. Our investigations aim to show that D.L. is a workable analytical technique covering a large number of disciplinary fields, from agriculture to pollution control and from medical diagnostics to food quality control. The authors have conducted systematic research about D.L. from unicellular alga Acetabularia acetabulum to Saccharomyces cerevisiae yeast cultures and about more complex systems such as Soya seed (Glycine max, L.) and its dependence on sample preparation, history, intracellular signaling, metabolism and pollutant presence. We will discuss the most relevant results together with theoretical considerations on the basic interaction at work between biological systems and electromagnetic fields.

  13. Morphological classification of plant cell deaths

    PubMed Central

    van Doorn, W G; Beers, E P; Dangl, J L; Franklin-Tong, V E; Gallois, P; Hara-Nishimura, I; Jones, A M; Kawai-Yamada, M; Lam, E; Mundy, J; Mur, L A J; Petersen, M; Smertenko, A; Taliansky, M; Van Breusegem, F; Wolpert, T; Woltering, E; Zhivotovsky, B; Bozhkov, P V

    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 classification of PCD in plants. Here we suggest a classification based on morphological criteria. According to this classification, the use of the term ‘apoptosis' is not justified in plants, but at least two classes of PCD can be distinguished: vacuolar cell death and necrosis. During vacuolar cell death, the cell contents are removed by a combination of autophagy-like process and release of hydrolases from collapsed lytic vacuoles. Necrosis is characterised by early rupture of the plasma membrane, shrinkage of the protoplast and absence of vacuolar cell death features. Vacuolar cell death is common during tissue and organ formation and elimination, whereas necrosis is typically found under abiotic stress. Some examples of plant PCD cannot be ascribed to either major class and are therefore classified as separate modalities. These are PCD associated with the hypersensitive response to biotrophic pathogens, which can express features of both necrosis and vacuolar cell death, PCD in starchy cereal endosperm and during self-incompatibility. The present classification is not static, but will be subject to further revision, especially when specific biochemical pathways are better defined. PMID:21494263

  14. Programmed cell death in cereal aleurone.

    PubMed

    Fath, A; Bethke, P; Lonsdale, J; Meza-Romero, R; Jones, R

    2000-10-01

    Progress in understanding programmed cell death (PCD) in the cereal aleurone is described. Cereal aleurone cells are specialized endosperm cells that function to synthesize and secrete hydrolytic enzymes that break down reserves in the starchy endosperm. Unlike the cells of the starchy endosperm, aleurone cells are viable in mature grain but undergo PCD when germination is triggered or when isolated aleurone layers or protoplasts are incubated in gibberellic acid (GA). Abscisic acid (ABA) slows down the process of aleurone cell death and isolated aleurone protoplasts can be kept alive in media containing ABA for up to 6 months. Cell death in barley aleurone occurs only after cells become highly vacuolated and is manifested in an abrupt loss of plasma membrane integrity. Aleurone cell death does not follow the apoptotic pathway found in many animal cells. The hallmarks of apoptosis, including internucleosomal DNA cleavage, plasma membrane and nuclear blebbing and formation of apoptotic bodies, are not observed in dying aleurone cells. PCD in barley aleurone cells is accompanied by the accumulation of a spectrum of nuclease and protease activities and the loss of organelles as a result of cellular autolysis.

  15. Caspase-3-mediated degradation of condensin Cap-H regulates mitotic cell death.

    PubMed

    Lai, S-K; Wong, C-H; Lee, Y-P; Li, H-Y

    2011-06-01

    Mitotic death is a major form of cell death in cancer cells that have been treated with chemotherapeutic drugs. However, the mechanisms underlying this form of cell death is poorly understood. Here, we report that the loss of chromosome integrity is an important determinant of mitotic death. During prolonged mitotic arrest, caspase-3 is activated and it cleaves Cap-H, a subunit of condensin I. The depletion of Cap-H results in the loss of condensin I complex at the chromosomes, thus affecting the integrity of the chromosomes. Consequently, DNA fragmentation by caspase-activated DNase is facilitated, thus driving the cell towards mitotic death. By expressing a caspase-resistant form of Cap-H, mitotic death is abrogated and the cells are able to reenter interphase after a long mitotic delay. Taken together, we provide new insights into the molecular events that occur during mitotic death.

  16. Nineteenth century research on cell death.

    PubMed

    Clarke, P G H; Clarke, S

    2012-10-01

    This paper reviews research on cell death in the 19th C. The first report of cell death was by Vogt in 1842, which was remarkably soon after the establishment of the cell theory by Schleiden and Schwann between 1838 and 1842. Initial studies on cell death, including that of Vogt, focused on its occurrence in metamorphosis (Vogt, 1842; Prévost and Lebert, 1844; Weismann, 1863-1866) or in blatant pathology (Virchow, 1858), but as histological techniques improved it was found to be involved in more subtle roles in numerous situations including endochondral ossification (Stieda, 1872), ovarian follicle atresia (Flemming, 1885), cell turnover (Nissen, 1886), the wholesale loss of a population of sensory neurons in fish (Beard, 1889), and the naturally occurring histogenetic death of myocytes (Felix, 1889) and neurons (Collin, 1906). The current categorization of cell death into about three main morphological types has 19th century roots in that apoptosis was well described by Flemming (1885), who called it chromatolysis, and various authors including Noetzel (1895) proposed a threefold classification. This article is part of a Special Issue entitled "Apoptosis: Four Decades Later". PMID:23069997

  17. Programmed cell death and hybrid incompatibility.

    PubMed

    Frank, S A; Barr, C M

    2003-01-01

    We propose a new theory to explain developmental aberrations in plant hybrids. In our theory, hybrid incompatibilities arise from imbalances in the mechanisms that cause male sterility in hermaphroditic plants. Mitochondria often cause male sterility by killing the tapetal tissue that nurtures pollen mother cells. Recent evidence suggests that mitochondria destroy the tapetum by triggering standard pathways of programmed cell death. Some nuclear genotypes repress mitochondrial male sterility and restore pollen fertility. Normal regulation of tapetal development therefore arises from a delicate balance between the disruptive effects of mitochondria and the defensive countermeasures of the nuclear genes. In hybrids, incompatibilities between male-sterile mitochondria and nuclear restorers may frequently upset the regulatory control of programmed cell death, causing tapetal abnormalities and male sterility. We propose that hybrid misregulation of programmed cell death may also spill over into other tissues, explaining various developmental aberrations observed in hybrids.

  18. Parvovirus infection-induced cell death and cell cycle arrest

    PubMed Central

    Chen, Aaron Yun; Qiu, Jianming

    2011-01-01

    The cytopathic effects induced during parvovirus infection have been widely documented. Parvovirus infection-induced cell death is often directly associated with disease outcomes (e.g., anemia resulting from loss of erythroid progenitors during parvovirus B19 infection). Apoptosis is the major form of cell death induced by parvovirus infection. However, nonapoptotic cell death, namely necrosis, has also been reported during infection of the minute virus of mice, parvovirus H-1 and bovine parvovirus. Recent studies have revealed multiple mechanisms underlying the cell death during parvovirus infection. These mechanisms vary in different parvoviruses, although the large nonstructural protein (NS)1 and the small NS proteins (e.g., the 11 kDa of parvovirus B19), as well as replication of the viral genome, are responsible for causing infection-induced cell death. Cell cycle arrest is also common, and contributes to the cytopathic effects induced during parvovirus infection. While viral NS proteins have been indicated to induce cell cycle arrest, increasing evidence suggests that a cellular DNA damage response triggered by an invading single-stranded parvoviral genome is the major inducer of cell cycle arrest in parvovirus-infected cells. Apparently, in response to infection, cell death and cell cycle arrest of parvovirus-infected cells are beneficial to the viral cell lifecycle (e.g., viral DNA replication and virus egress). In this article, we will discuss recent advances in the understanding of the mechanisms underlying parvovirus infection-induced cell death and cell cycle arrest. PMID:21331319

  19. Insulin withdrawal-induced cell death in adult hippocampal neural stem cells as a model of autophagic cell death.

    PubMed

    Baek, Seung-Hoon; Kim, Eun-Kyoung; Goudreau, John L; Lookingland, Keith J; Kim, Seong Who; Yu, Seong-Woon

    2009-02-01

    The term "autophagic cell death" was coined to describe a form of cell death associated with the massive formation of autophagic vacuoles without signs of apoptosis. However, questions about the actual role of autophagy and its molecular basis in cell death remain to be elucidated. We recently reported that adult hippocampal neural stem (HCN) cells undergo autophagic cell death following insulin withdrawal. Insulin-deprived HCN cells exhibit morphological and biochemical markers of autophagy, including accumulation of Beclin 1 and the type II form of microtubule-associated protein 1 light chain 3 (LC3) without evidence of apoptosis. Suppression of autophagy by knockdown of Atg7 reduces cell death, whereas promotion of autophagy with rapamycin augments cell death in insulin-deficient HCN cells. These data reveal a causative role of autophagy in insulin withdrawal-induced HCN cell death. HCN cells have intact apoptotic capability despite the lack of apoptosis following insulin withdrawal. Our study demonstrates that autophagy is the default cell death mechanism in insulin-deficient HCN cells, and provides a genuine model of autophagic cell death in apoptosis-intact cells. Novel insight into molecular mechanisms of this underappreciated form of programmed cell death should facilitate the development of therapeutic methods to cope with human diseases caused by dysregulated cell death.

  20. Time-Lapse Imaging of Cell Death.

    PubMed

    Wallberg, Fredrik; Tenev, Tencho; Meier, Pascal

    2016-03-01

    The best approach to distinguish between necrosis and apoptosis is time-lapse video microscopy. This technique enables a biological process to be photographed at regular intervals over a period, which may last from a few hours to several days, and can be applied to cells in culture or in vivo. We have established two time-lapse microscopy methods based on different ways of calculating cell death: semiautomated and automated. In the semiautomated approach, cell death can be visualized by staining with combinations of Alexa Fluor 647-conjugated Annexin V and Sytox Green (SG), or Annexin V(FITC) and Propidium iodide (PI). The automated method is similar except that all cells are labeled with dyes. This allows faster quantification of data. To this end Cell Tracker Green is used to label all cells at time zero in combination with PI and Alexa Fluor 647-conjugated Annexin V. Necrotic cell death is accompanied by either simultaneous labeling with Annexin V and PI or SG (double-positive), or direct PI or SG staining. Additionally, necrotic cells display characteristic morphology, such as cytoplasmic swelling. In contrast to necrosis where membrane permeabilization is an early event, cells that die by apoptosis lose their membrane permeability relatively late. Therefore, the time between Annexin V staining and PI or SG uptake (double-positive) can be used to distinguish necrosis from apoptosis. This protocol describes the analysis of cell death by time-lapse imaging of HT1080 and L929 cells stained with these dyes, but it can be readily adapted to other cell types of interest. PMID:26933245

  1. Quantitative analysis of delayed neuronal death in the hippocampal subfields of SHRSP and SHR.

    PubMed

    Daisu, Mitsuhiro; Hatta, Toshihisa; Sakurai-Yamashita, Yasuko; Nabika, Toru; Moritake, Kouzo

    2009-06-01

    Transient forebrain ischemia and reperfusion induces delayed neuronal death (DND) in the hippocampal Cornu Ammonis 1 (CA1) subfield of stroke-prone spontaneously hypertensive rat (SHRSP). The vulnerability to DND is potentially related to the genetic susceptibility to stroke in this strain. To elucidate the mechanism of DND in SHRSP, however, it is essential to establish a method for quantitative evaluation of DND, which is not available yet. Male SHRSPs and spontaneously hypertensive rats (SHRs) at 12 weeks of age were used in the experiment. The bilateral common carotid arteries were surgically occluded with aneurysmal clips for 10 min. The brain was taken out 7 days after the experiment of the transient ischemia, and was sliced into serial coronal sections. Quantitative estimation of the number of viable pyramidal cells in the CA1 and CA2/3 subfields was performed based on the stereology with a random and systematic sampling. The transient ischemia and reperfusion (TIR) significantly reduced the number of viable pyramidal cells in CA1 of SHRSP (61000 +/- 20100 in TIR vs. 128500 +/- 21900 in the sham-operation, P < 0.000001 by Student's t-test), while no significant difference was observed in SHR (140300 +/- 30800 in TIR vs. 128200 +/- 16700 in the sham-operation, P = 0.35). Further analysis revealed a dorsal-ventral gradient in the distribution of DND in CA1 of SHRSP with the most severe change in the dorsal area. The quantitative measurement using a stereological method is useful in the precise evaluation of DND in SHRSP. This method can be applied in the studies of effects of medical treatments on the 'ischemia/reperfusion' insult.

  2. The apoptosome: signalling platform of cell death.

    PubMed

    Riedl, Stefan J; Salvesen, Guy S

    2007-05-01

    Recent work on the initial switches that trigger cell death has revealed surprising inventions of nature that ensure the ordered suicide of a cell that has been selected for demise. Particularly intriguing is how a signal--the release of cytochrome c from the mitochondria--is translated into the activation of the death cascade, which leads to a point of no return. Now there is new understanding of how this crucial process is delicately handled by a cytosolic signalling platform known as the apoptosome. The formation of the apoptosome and the activation of its effector, caspase-9, reveals a sophisticated mechanism that might be more common than was initially thought. PMID:17377525

  3. Master stability islands for amplitude death in networks of delay-coupled oscillators.

    PubMed

    Huddy, Stanley R; Sun, Jie

    2016-05-01

    This paper presents a master stability function (MSF) approach for analyzing the stability of amplitude death (AD) in networks of delay-coupled oscillators. Unlike the familiar MSFs for instantaneously coupled networks, which typically have a single input encoding for the effects of the eigenvalues of the network Laplacian matrix, for delay-coupled networks we show that such MSFs generally require two additional inputs: the time delay and the coupling strength. To utilize the MSF for determining the stability of AD of general networks for a chosen nonlinear system (node dynamics) and coupling function, we introduce the concept of master stability islands (MSIs), which are two-dimensional stability islands of the delay-coupling parameter space together with a third dimension ("altitude") encoding for eigenvalues that result in stable AD. We numerically compute the MSFs and visualize the corresponding MSIs for several common chaotic systems including the Rössler, the Lorenz, and Chen's system and find that it is generally possible to achieve AD and that a nonzero time delay is necessary for the stabilization of the AD states.

  4. Master stability islands for amplitude death in networks of delay-coupled oscillators

    NASA Astrophysics Data System (ADS)

    Huddy, Stanley R.; Sun, Jie

    2016-05-01

    This paper presents a master stability function (MSF) approach for analyzing the stability of amplitude death (AD) in networks of delay-coupled oscillators. Unlike the familiar MSFs for instantaneously coupled networks, which typically have a single input encoding for the effects of the eigenvalues of the network Laplacian matrix, for delay-coupled networks we show that such MSFs generally require two additional inputs: the time delay and the coupling strength. To utilize the MSF for determining the stability of AD of general networks for a chosen nonlinear system (node dynamics) and coupling function, we introduce the concept of master stability islands (MSIs), which are two-dimensional stability islands of the delay-coupling parameter space together with a third dimension ("altitude") encoding for eigenvalues that result in stable AD. We numerically compute the MSFs and visualize the corresponding MSIs for several common chaotic systems including the Rössler, the Lorenz, and Chen's system and find that it is generally possible to achieve AD and that a nonzero time delay is necessary for the stabilization of the AD states.

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

    PubMed Central

    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. PMID:27716809

  6. Autophagy prevents autophagic cell death in Tetrahymena in response to oxidative stress.

    PubMed

    Zhang, Si-Wei; Feng, Jiang-Nan; Cao, Yi; Meng, Li-Ping; Wang, Shu-Lin

    2015-05-18

    Autophagy is a major cellular pathway used to degrade long-lived proteins or organelles that may be damaged due to increased reactive oxygen species (ROS) generated by cellular stress. Autophagy typically enhances cell survival, but it may also act to promote cell death under certain conditions. The mechanism underlying this paradox, however, remains unclear. We showed that Tetrahymena cells exerted increased membrane-bound vacuoles characteristic of autophagy followed by autophagic cell death (referred to as cell death with autophagy) after exposure to hydrogen peroxide. Inhibition of autophagy by chloroquine or 3-methyladenine significantly augmented autophagic cell death induced by hydrogen peroxide. Blockage of the mitochondrial electron transport chain or starvation triggered activation of autophagy followed by cell death by inducing the production of ROS due to the loss of mitochondrial membrane potential. This indicated a regulatory role of mitochondrial ROS in programming autophagy and autophagic cell death in Tetrahymena. Importantly, suppression of autophagy enhanced autophagic cell death in Tetrahymena in response to elevated ROS production from starvation, and this was reversed by antioxidants. Therefore, our results suggest that autophagy was activated upon oxidative stress to prevent the initiation of autophagic cell death in Tetrahymena until the accumulation of ROS passed the point of no return, leading to delayed cell death in Tetrahymena.

  7. Autophagy prevents autophagic cell death in Tetrahymena in response to oxidative stress

    PubMed Central

    ZHANG, Si-Wei; FENG, Jiang-Nan; CAO, Yi; MENG, Li-Ping; WANG, Shu-Lin

    2015-01-01

    Autophagy is a major cellular pathway used to degrade long-lived proteins or organelles that may be damaged due to increased reactive oxygen species (ROS) generated by cellular stress. Autophagy typically enhances cell survival, but it may also act to promote cell death under certain conditions. The mechanism underlying this paradox, however, remains unclear. We showed that Tetrahymena cells exerted increased membrane-bound vacuoles characteristic of autophagy followed by autophagic cell death (referred to as cell death with autophagy) after exposure to hydrogen peroxide. Inhibition of autophagy by chloroquine or 3-methyladenine significantly augmented autophagic cell death induced by hydrogen peroxide. Blockage of the mitochondrial electron transport chain or starvation triggered activation of autophagy followed by cell death by inducing the production of ROS due to the loss of mitochondrial membrane potential. This indicated a regulatory role of mitochondrial ROS in programming autophagy and autophagic cell death in Tetrahymena. Importantly, suppression of autophagy enhanced autophagic cell death in Tetrahymena in response to elevated ROS production from starvation, and this was reversed by antioxidants. Therefore, our results suggest that autophagy was activated upon oxidative stress to prevent the initiation of autophagic cell death in Tetrahymena until the accumulation of ROS passed the point of no return, leading to delayed cell death in Tetrahymena. PMID:26018860

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

    PubMed

    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.

  9. Cell death pathways associated with PDT

    NASA Astrophysics Data System (ADS)

    Kessel, David; Reiners, John J., Jr.

    2006-02-01

    Photodynamic therapy leads to both direct and indirect tumor cell death. The latter also involves the consequences of vascular shut-down and immunologic effects. While these factors are a major factor in tumor eradication, there is usually an element of direct cell killing that can reduce the cell population by as much as 2-3 logs. Necrosis was initially believed to represent the predominant PDT death mechanism. An apoptotic response to PDT was first reported by Oleinick in 1991, using a sensitizer that targets the anti-apoptotic protein Bcl-2. Apoptosis leads to fragmentation of DNA and of cells into apoptotic bodies that are removed by phagocytosis. Inflammatory effects are minimized, and the auto- catalytic elements of the process can amplify the death signal. In this study, we examined consequences of Bcl-2 photodamage by a porphycene sensitizer that targets the ER and causes photodamage to the anti-apoptotic protein Bcl-2. Death patterns after Bcl-2 inactivation by a small-molecular antagonist were also assessed. In addition to apoptosis, we also characterized a hitherto undescribed PDT effect, the initiation of autophagy. Autophagy was initially identified as a cell survival pathway, allowing the recycling of components as nutrients become scarce. We propose that autophagy can also represent both a potential survival pathway after PDT damage to cellular organelles, as well as a cell-death pathway. Recent literature reports indicate that autophagy, as well as apoptosis, can be evoked after down-regulation of Bcl-2, a result consistent with results reported here.

  10. Programmed cell death in seeds of angiosperms.

    PubMed

    López-Fernández, María Paula; Maldonado, Sara

    2015-12-01

    During the diversification of angiosperms, seeds have evolved structural, chemical, molecular and physiologically developing changes that specially affect the nucellus and endosperm. All through seed evolution, programmed cell death (PCD) has played a fundamental role. However, examples of PCD during seed development are limited. The present review examines PCD in integuments, nucellus, suspensor and endosperm in those representative examples of seeds studied to date.

  11. Nanomaterials Toxicity and Cell Death Modalities

    PubMed Central

    De Stefano, Daniela; Carnuccio, Rosa; Maiuri, Maria Chiara

    2012-01-01

    In the last decade, the nanotechnology advancement has developed a plethora of novel and intriguing nanomaterial application in many sectors, including research and medicine. However, many risks have been highlighted in their use, particularly related to their unexpected toxicity in vitro and in vivo experimental models. This paper proposes an overview concerning the cell death modalities induced by the major nanomaterials. PMID:23304518

  12. Lipids and cell death in yeast

    PubMed Central

    Eisenberg, Tobias; Büttner, Sabrina

    2014-01-01

    Understanding lipid-induced malfunction represents a major challenge of today's biomedical research. The connection of lipids to cellular and organ dysfunction, cell death, and disease (often referred to as lipotoxicity) is more complex than the sole lipotoxic effects of excess free fatty acids and requires genetically tractable model systems for mechanistic investigation. We herein summarize recent advances in the field of lipid-induced toxicity that employ the established model system for cell death and aging research of budding yeast Saccharomyces cerevisiae. Studies in yeast have shed light on various aspects of lipotoxicity, including free fatty acid toxicity, sphingolipid-modulated cell death as well as the involvement of cardiolipin and lipid peroxidation in the mitochondrial pathways of apoptosis. Regimens used range from exogenously applied lipids, genetic modulation of lipolysis and triacylglyceride synthesis, variations in sphingolipid/ceramide metabolism as well as changes in peroxisome function by either genetic or pharmacological means. In future, the yeast model of programmed cell death will further contribute to the clarification of crucial questions of lipid-associated malfunction. PMID:24119111

  13. Bifurcation Analysis of Fractional Order Single Cell with Delay

    NASA Astrophysics Data System (ADS)

    Çelik, Vedat

    This paper presents the bifurcation analysis of fractional order model of delayed single cell which is proposed for delayed cellular neural networks with respect to the time delay τ. The bifurcation points, time delay τc, are determined by modified Mikhailov stability criterion for a range of fractional delayed cell order 0.3 ≤ q < 1. Numerical results obtained from Adams-Bashforth-Moulton method demonstrate that the supercritical Hopf bifurcation occurs in the system.

  14. Hemoglobins, programmed cell death and somatic embryogenesis.

    PubMed

    Hill, Robert D; Huang, Shuanglong; Stasolla, Claudio

    2013-10-01

    Programmed cell death (PCD) is a universal process in all multicellular organisms. It is a critical component in a diverse number of processes ranging from growth and differentiation to response to stress. Somatic embryogenesis is one such process where PCD is significantly involved. Nitric oxide is increasingly being recognized as playing a significant role in regulating PCD in both mammalian and plant systems. Plant hemoglobins scavenge NO, and evidence is accumulating that events that modify NO levels in plants also affect hemoglobin expression. Here, we review the process of PCD, describing the involvement of NO and plant hemoglobins in the process. NO is an effector of cell death in both plants and vertebrates, triggering the cascade of events leading to targeted cell death that is a part of an organism's response to stress or to tissue differentiation and development. Expression of specific hemoglobins can alter this response in plants by scavenging the NO, thus, interrupting the death process. Somatic embryogenesis is used as a model system to demonstrate how cell-specific expression of different classes of hemoglobins can alter the embryogenic process, affecting hormone synthesis, cell metabolite levels and genes associated with PCD and embryogenic competence. We propose that plant hemoglobins influence somatic embryogenesis and PCD through cell-specific expression of a distinct plant hemoglobin. It is based on the premise that both embryogenic competence and PCD are strongly influenced by cellular NO levels. Increases in cellular NO levels result in elevated Zn(2+) and reactive-oxygen species associated with PCD, but they also result in decreased expression of MYC2, a transcription factor that is a negative effector of indoleacetic acid synthesis, a hormone that positively influences embryogenic competence. Cell-specific hemoglobin expression reduces NO levels as a result of NO scavenging, resulting in cell survival.

  15. Decoding cell death signals in liver inflammation.

    PubMed

    Brenner, Catherine; Galluzzi, Lorenzo; Kepp, Oliver; Kroemer, Guido

    2013-09-01

    Inflammation can be either beneficial or detrimental to the liver, depending on multiple factors. Mild (i.e., limited in intensity and destined to resolve) inflammatory responses have indeed been shown to exert consistent hepatoprotective effects, contributing to tissue repair and promoting the re-establishment of homeostasis. Conversely, excessive (i.e., disproportionate in intensity and permanent) inflammation may induce a massive loss of hepatocytes and hence exacerbate the severity of various hepatic conditions, including ischemia-reperfusion injury, systemic metabolic alterations (e.g., obesity, diabetes, non-alcoholic fatty liver disorders), alcoholic hepatitis, intoxication by xenobiotics and infection, de facto being associated with irreversible liver damage, fibrosis, and carcinogenesis. Both liver-resident cells (e.g., Kupffer cells, hepatic stellate cells, sinusoidal endothelial cells) and cells that are recruited in response to injury (e.g., monocytes, macrophages, dendritic cells, natural killer cells) emit pro-inflammatory signals including - but not limited to - cytokines, chemokines, lipid messengers, and reactive oxygen species that contribute to the apoptotic or necrotic demise of hepatocytes. In turn, dying hepatocytes release damage-associated molecular patterns that-upon binding to evolutionary conserved pattern recognition receptors-activate cells of the innate immune system to further stimulate inflammatory responses, hence establishing a highly hepatotoxic feedforward cycle of inflammation and cell death. In this review, we discuss the cellular and molecular mechanisms that account for the most deleterious effect of hepatic inflammation at the cellular level, that is, the initiation of a massive cell death response among hepatocytes.

  16. Autophagic and apoptotic cell death in amniotic epithelial cells.

    PubMed

    Shen, Z-Y; Li, E-M; Lu, S-Q; Shen, J; Cai, Y-M; Wu, Y-E; Zheng, R-M; Tan, L-J; Xu, L-Y

    2008-11-01

    The aim of this paper is to determine if autophagic cell death is associated with apoptosis and whether it participates in the process of term amniotic rupture. Forty pieces of fresh term amnions, including twenty from a position near the margin of the placentas and twenty from the margin of the naturally ruptured part of the placentas in term gestation were collected, respectively. The amnions were examined by scanning electron microscopy (SEM) and amniotic epithelial (AE) cells were examined by transmission electron microscopy (TEM). Autophagic and apoptotic cell death (PCD) were assayed by laser scanning confocal microscopy (LSCM) or flow cytometry using monodansylcadaverin (MDC) and propidium iodide (PI) stain. BCL(2) and BAX were examined by immunoblotting. Under SEM the amniotic epithelia appeared normal in the position near the placenta. They had an atrophied appearance in the margin of their natural broken parts. In the AE cells PCD was divided into three subtypes by TEM: autophagic cell death with positive stains of MDC and PI; apoptotic cell death; and the mixed type. Quantitative detection showed that there were more death cells, including autophagic and apoptotic, in the AE cells near the ruptured parts than near the placentas. An increased expression of BAX and a decreased expression of BCL(2) protein in the AE cells near the broken margin were observed. Apoptotic and autophagic cell death by the intrinsic pathway are the basic event in the AE cell and they are involved in the cause of membrane rupture of the human amnion in term gestation.

  17. Sickle Cell Trait Not Linked to Early Death in Study

    MedlinePlus

    ... html Sickle Cell Trait Not Linked to Early Death in Study However, black soldiers with the gene ... cell gene variant, are at risk of premature death. People with the sickle cell gene variant do ...

  18. Cell Death and Autophagy in TB

    PubMed Central

    Moraco, Andrew H.; Kornfeld, Hardy

    2014-01-01

    Mycobacterium tuberculosis has succeeded in infecting one third of the human race though inhibition or evasion of innate and adaptive immunity. The pathogen is a facultative intracellular parasite that uses the niche provided by mononuclear phagocytes for its advantage. Complex interactions determine whether the bacillus will or will not be delivered to acidified lysosomes, whether the host phagocyte will survive infection or die, and whether the timing and mode of cell death works to the advantage of the host or the pathogen. Here we discuss cell death and autophagy in TB. These fundamental processes of cell biology feature in all aspects of TB pathogenesis and may be exploited to the treatment or prevention of TB disease. PMID:25453227

  19. Programmed cell death in the plant immune system

    PubMed Central

    Coll, N S; Epple, P; Dangl, J L

    2011-01-01

    Cell death has a central role in innate immune responses in both plants and animals. Besides sharing striking convergences and similarities in the overall evolutionary organization of their innate immune systems, both plants and animals can respond to infection and pathogen recognition with programmed cell death. The fact that plant and animal pathogens have evolved strategies to subvert specific cell death modalities emphasizes the essential role of cell death during immune responses. The hypersensitive response (HR) cell death in plants displays morphological features, molecular architectures and mechanisms reminiscent of different inflammatory cell death types in animals (pyroptosis and necroptosis). In this review, we describe the molecular pathways leading to cell death during innate immune responses. Additionally, we present recently discovered caspase and caspase-like networks regulating cell death that have revealed fascinating analogies between cell death control across both kingdoms. PMID:21475301

  20. Programmed cell death during quinoa perisperm development.

    PubMed

    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.

  1. UV-Induced cell death in plants.

    PubMed

    Nawkar, Ganesh M; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

    2013-01-14

    Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400-700 nm), plants are exposed to UV light, which is comprised of UV-C (below 280 nm), UV-B (280-320 nm) and UV-A (320-390 nm). The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS). Arabidopsis metacaspase-8 (AtMC8) is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1) gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD).

  2. Ferroptosis is an autophagic cell death process.

    PubMed

    Gao, Minghui; Monian, Prashant; Pan, Qiuhui; Zhang, Wei; Xiang, Jenny; Jiang, Xuejun

    2016-09-01

    Ferroptosis is an iron-dependent form of regulated necrosis. It is implicated in various human diseases, including ischemic organ damage and cancer. Here, we report the crucial role of autophagy, particularly autophagic degradation of cellular iron storage proteins (a process known as ferritinophagy), in ferroptosis. Using RNAi screening coupled with subsequent genetic analysis, we identified multiple autophagy-related genes as positive regulators of ferroptosis. Ferroptosis induction led to autophagy activation and consequent degradation of ferritin and ferritinophagy cargo receptor NCOA4. Consistently, inhibition of ferritinophagy by blockage of autophagy or knockdown of NCOA4 abrogated the accumulation of ferroptosis-associated cellular labile iron and reactive oxygen species, as well as eventual ferroptotic cell death. Therefore, ferroptosis is an autophagic cell death process, and NCOA4-mediated ferritinophagy supports ferroptosis by controlling cellular iron homeostasis. PMID:27514700

  3. Cell Death and Deubiquitinases: Perspectives in Cancer

    PubMed Central

    Bhattacharya, Seemana

    2014-01-01

    The process of cell death has important physiological implications. At the organism level it is mostly involved in maintenance of tissue homeostasis. At the cellular level, the strategies of cell death may be categorized as either suicide or sabotage. The mere fact that many of these processes are programmed and that these are often deregulated in pathological conditions is seed to thought. The various players that are involved in these pathways are highly regulated. One of the modes of regulation is via post-translational modifications such as ubiquitination and deubiquitination. In this review, we have first dealt with the different modes and pathways involved in cell death and then we have focused on the regulation of several proteins in these signaling cascades by the different deubiquitinating enzymes, in the perspective of cancer. The study of deubiquitinases is currently in a rather nascent stage with limited knowledge both in vitro and in vivo, but the emerging roles of the deubiquitinases in various processes and their specificity have implicated them as potential targets from the therapeutic point of view. This review throws light on another aspect of cancer therapeutics by targeting the deubiquitinating enzymes. PMID:25121098

  4. Selective inhibition of apicoplast tryptophanyl-tRNA synthetase causes delayed death in Plasmodium falciparum

    PubMed Central

    Pasaje, Charisse Flerida A.; Cheung, Vanessa; Kennedy, Kit; Lim, Erin E.; Baell, Jonathan B.; Griffin, Michael D. W.; Ralph, Stuart A.

    2016-01-01

    The malaria parasite Plasmodium falciparum relies on efficient protein translation. An essential component of translation is the tryptophanyl-tRNA synthetase (TrpRS) that charges tRNAtrp. Here we characterise two isoforms of TrpRS in Plasmodium; one eukaryotic type localises to the cytosol and a bacterial type localises to the remnant plastid (apicoplast). We show that the apicoplast TrpRS aminoacylates bacterial tRNAtrp while the cytosolic TrpRS charges eukaryotic tRNAtrp. An inhibitor of bacterial TrpRSs, indolmycin, specifically inhibits aminoacylation by the apicoplast TrpRS in vitro, and inhibits ex vivo Plasmodium parasite growth, killing parasites with a delayed death effect characteristic of apicoplast inhibitors. Indolmycin treatment ablates apicoplast inheritance and is rescuable by addition of the apicoplast metabolite isopentenyl pyrophosphate (IPP). These data establish that inhibition of an apicoplast housekeeping enzyme leads to loss of the apicoplast and this is sufficient for delayed death. Apicoplast TrpRS is essential for protein translation and is a promising, specific antimalarial target. PMID:27277538

  5. Decoding cell death signals in liver inflammation.

    PubMed

    Brenner, Catherine; Galluzzi, Lorenzo; Kepp, Oliver; Kroemer, Guido

    2013-09-01

    Inflammation can be either beneficial or detrimental to the liver, depending on multiple factors. Mild (i.e., limited in intensity and destined to resolve) inflammatory responses have indeed been shown to exert consistent hepatoprotective effects, contributing to tissue repair and promoting the re-establishment of homeostasis. Conversely, excessive (i.e., disproportionate in intensity and permanent) inflammation may induce a massive loss of hepatocytes and hence exacerbate the severity of various hepatic conditions, including ischemia-reperfusion injury, systemic metabolic alterations (e.g., obesity, diabetes, non-alcoholic fatty liver disorders), alcoholic hepatitis, intoxication by xenobiotics and infection, de facto being associated with irreversible liver damage, fibrosis, and carcinogenesis. Both liver-resident cells (e.g., Kupffer cells, hepatic stellate cells, sinusoidal endothelial cells) and cells that are recruited in response to injury (e.g., monocytes, macrophages, dendritic cells, natural killer cells) emit pro-inflammatory signals including - but not limited to - cytokines, chemokines, lipid messengers, and reactive oxygen species that contribute to the apoptotic or necrotic demise of hepatocytes. In turn, dying hepatocytes release damage-associated molecular patterns that-upon binding to evolutionary conserved pattern recognition receptors-activate cells of the innate immune system to further stimulate inflammatory responses, hence establishing a highly hepatotoxic feedforward cycle of inflammation and cell death. In this review, we discuss the cellular and molecular mechanisms that account for the most deleterious effect of hepatic inflammation at the cellular level, that is, the initiation of a massive cell death response among hepatocytes. PMID:23567086

  6. Current and Emerging Biomarkers of Cell Death in Human Disease

    PubMed Central

    Li, Kongning; Wu, Deng; Chen, Xi; Zhang, Ting; Zhang, Lu; Yi, Ying; Miao, Zhengqiang; Jin, Nana; Bi, Xiaoman; Wang, Hongwei; Wang, Dong

    2014-01-01

    Cell death is a critical biological process, serving many important functions within multicellular organisms. Aberrations in cell death can contribute to the pathology of human diseases. Significant progress made in the research area enormously speeds up our understanding of the biochemical and molecular mechanisms of cell death. According to the distinct morphological and biochemical characteristics, cell death can be triggered by extrinsic or intrinsic apoptosis, regulated necrosis, autophagic cell death, and mitotic catastrophe. Nevertheless, the realization that all of these efforts seek to pursue an effective treatment and cure for the disease has spurred a significant interest in the development of promising biomarkers of cell death to early diagnose disease and accurately predict disease progression and outcome. In this review, we summarize recent knowledge about cell death, survey current and emerging biomarkers of cell death, and discuss the relationship with human diseases. PMID:24949464

  7. Cell Death Control by Matrix Metalloproteinases.

    PubMed

    Zimmermann, Dirk; Gomez-Barrera, Juan A; Pasule, Christian; Brack-Frick, Ursula B; Sieferer, Elke; Nicholson, Tim M; Pfannstiel, Jens; Stintzi, Annick; Schaller, Andreas

    2016-06-01

    In contrast to mammalian matrix metalloproteinases (MMPs) that play important roles in the remodeling of the extracellular matrix in animals, the proteases responsible for dynamic modifications of the plant cell wall are largely unknown. A possible involvement of MMPs was addressed by cloning and functional characterization of Sl2-MMP and Sl3-MMP from tomato (Solanum lycopersicum). The two tomato MMPs were found to resemble mammalian homologs with respect to gelatinolytic activity, substrate preference for hydrophobic amino acids on both sides of the scissile bond, and catalytic properties. In transgenic tomato seedlings silenced for Sl2/3-MMP expression, necrotic lesions were observed at the base of the hypocotyl. Cell death initiated in the epidermis and proceeded to include outer cortical cell layers. In later developmental stages, necrosis spread, covering the entire stem and extending into the leaves of MMP-silenced plants. The subtilisin-like protease P69B was identified as a substrate of Sl2- and Sl3-MMP. P69B was shown to colocalize with Sl-MMPs in the apoplast of the tomato hypocotyl, it exhibited increased stability in transgenic plants silenced for Sl-MMP activity, and it was cleaved and inactivated by Sl-MMPs in vitro. The induction of cell death in Sl2/3-MMP-silenced plants depended on P69B, indicating that Sl2- and Sl3-MMP act upstream of P69B in an extracellular proteolytic cascade that contributes to the regulation of cell death in tomato. PMID:27208293

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

    PubMed

    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.

  9. Cell death goes LIVE: technological advances in real-time tracking of cell death.

    PubMed

    Skommer, Joanna; Darzynkiewicz, Zbigniew; Wlodkowic, Donald

    2010-06-15

    Cell population can be viewed as a quantum system, which like Schrödinger's cat exists as a combination of survival- and death-allowing states. Tracking and understanding cell-to-cell variability in processes of high spatio-temporal complexity such as cell death is at the core of current systems biology approaches. As probabilistic modeling tools attempt to impute information inaccessible by current experimental approaches, advances in technologies for single-cell imaging and omics (proteomics, genomics, metabolomics) should go hand in hand with the computational efforts. Over the last few years we have made exciting technological advances that allow studies of cell death dynamically in real-time and with the unprecedented accuracy. These approaches are based on innovative fluorescent assays and recombinant proteins, bioelectrical properties of cells, and more recently also on state-of-the-art optical spectroscopy. Here, we review current status of the most innovative analytical technologies for dynamic tracking of cell death, and address the interdisciplinary promises and future challenges of these methods.

  10. ACCELERATED CELL DEATH2 suppresses mitochondrial oxidative bursts and modulates cell death in Arabidopsis

    PubMed Central

    Pattanayak, Gopal K.; Venkataramani, Sujatha; Hortensteiner, Stefan; Kunz, Lukas; Christ, Bastien; Moulin, Michael; Smith, Alison G.; Okamoto, Yukihiro; Tamiaki, Hitoshi; Sugishima, Masakazu; Greenberg, Jean T.

    2012-01-01

    SUMMARY The Arabidopsis ACCELERATED CELL DEATH 2 (ACD2) protein protects cells from programmed cell death (PCD) caused by endogenous porphyrin-related molecules like red chlorophyll catabolite or exogenous protoporphyrin IX. We previously found that during bacterial infection, ACD2, a chlorophyll breakdown enzyme, localizes to both chloroplasts and mitochondria in leaves. Additionally, acd2 cells show mitochondrial dysfunctions. In plants with acd2 and ACD2+ sectors, ACD2 functions cell autonomously, implicating a pro-death ACD2 substrate as cell non-autonomous in promoting spreading PCD. ACD2 targeted solely to mitochondria can reduce the accumulation of an ACD2 substrate that originates in chloroplasts, indicating that ACD2 substrate molecules are likely mobile within cells. Two different light-dependent reactive oxygen bursts in mitochondria play prominent and causal roles in the acd2 PCD phenotype. Finally, ACD2 can complement acd2 when targeted to mitochondria or chloroplasts, respectively, as long as it is catalytically active; the ability to bind substrate is not sufficient for ACD2 to function in vitro or in vivo. Together the data suggest that ACD2 localizes dynamically during infection to protect cells from pro-death mobile substrate molecules, some of which may originate in chloroplasts, but have major effects on mitochondria. PMID:21988537

  11. Accelerated cell death 2 suppresses mitochondrial oxidative bursts and modulates cell death in Arabidopsis.

    PubMed

    Pattanayak, Gopal K; Venkataramani, Sujatha; Hortensteiner, Stefan; Kunz, Lukas; Christ, Bastien; Moulin, Michael; Smith, Alison G; Okamoto, Yukihiro; Tamiaki, Hitoshi; Sugishima, Masakazu; Greenberg, Jean T

    2012-02-01

    The Arabidopsis ACCELERATED CELL DEATH 2 (ACD2) protein protects cells from programmed cell death (PCD) caused by endogenous porphyrin-related molecules like red chlorophyll catabolite or exogenous protoporphyrin IX. We previously found that during bacterial infection, ACD2, a chlorophyll breakdown enzyme, localizes to both chloroplasts and mitochondria in leaves. Additionally, acd2 cells show mitochondrial dysfunction. In plants with acd2 and ACD2 (+) sectors, ACD2 functions cell autonomously, implicating a pro-death ACD2 substrate as being cell non-autonomous in promoting the spread of PCD. ACD2 targeted solely to mitochondria can reduce the accumulation of an ACD2 substrate that originates in chloroplasts, indicating that ACD2 substrate molecules are likely to be mobile within cells. Two different light-dependent reactive oxygen bursts in mitochondria play prominent and causal roles in the acd2 PCD phenotype. Finally, ACD2 can complement acd2 when targeted to mitochondria or chloroplasts, respectively, as long as it is catalytically active: the ability to bind substrate is not sufficient for ACD2 to function in vitro or in vivo. Together, the data suggest that ACD2 localizes dynamically during infection to protect cells from pro-death mobile substrate molecules, some of which may originate in chloroplasts, but have major effects on mitochondria.

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

    ERIC Educational Resources Information Center

    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…

  13. Cellular Stress Responses: Cell Survival and Cell Death

    PubMed Central

    Fulda, Simone; Gorman, Adrienne M.; Hori, Osamu; Samali, Afshin

    2010-01-01

    Cells can respond to stress in various ways ranging from the activation of survival pathways to the initiation of cell death that eventually eliminates damaged cells. Whether cells mount a protective or destructive stress response depends to a large extent on the nature and duration of the stress as well as the cell type. Also, there is often the interplay between these responses that ultimately determines the fate of the stressed cell. The mechanism by which a cell dies (i.e., apoptosis, necrosis, pyroptosis, or autophagic cell death) depends on various exogenous factors as well as the cell's ability to handle the stress to which it is exposed. The implications of cellular stress responses to human physiology and diseases are manifold and will be discussed in this review in the context of some major world health issues such as diabetes, Parkinson's disease, myocardial infarction, and cancer. PMID:20182529

  14. Inhibition of caspases prevents ototoxic and ongoing hair cell death

    NASA Technical Reports Server (NTRS)

    Matsui, Jonathan I.; Ogilvie, Judith M.; Warchol, Mark E.

    2002-01-01

    Sensory hair cells die after acoustic trauma or ototoxic insults, but the signal transduction pathways that mediate hair cell death are not known. Here we identify several important signaling events that regulate the death of vestibular hair cells. Chick utricles were cultured in media supplemented with the ototoxic antibiotic neomycin and selected pharmacological agents that influence signaling molecules in cell death pathways. Hair cells that were treated with neomycin exhibited classically defined apoptotic morphologies such as condensed nuclei and fragmented DNA. Inhibition of protein synthesis (via treatment with cycloheximide) increased hair cell survival after treatment with neomycin, suggesting that hair cell death requires de novo protein synthesis. Finally, the inhibition of caspases promoted hair cell survival after neomycin treatment. Sensory hair cells in avian vestibular organs also undergo continual cell death and replacement throughout mature life. It is unclear whether the loss of hair cells stimulates the proliferation of supporting cells or whether the production of new cells triggers the death of hair cells. We examined the effects of caspase inhibition on spontaneous hair cell death in the chick utricle. Caspase inhibitors reduced the amount of ongoing hair cell death and ongoing supporting cell proliferation in a dose-dependent manner. In isolated sensory epithelia, however, caspase inhibitors did not affect supporting cell proliferation directly. Our data indicate that ongoing hair cell death stimulates supporting cell proliferation in the mature utricle.

  15. Apoptosis, oncosis, and necrosis. An overview of cell death.

    PubMed Central

    Majno, G.; Joris, I.

    1995-01-01

    The historical development of the cell death concept is reviewed, with special attention to the origin of the terms necrosis, coagulation necrosis, autolysis, physiological cell death, programmed cell death, chromatolysis (the first name of apoptosis in 1914), karyorhexis, karyolysis, and cell suicide, of which there are three forms: by lysosomes, by free radicals, and by a genetic mechanism (apoptosis). Some of the typical features of apoptosis are discussed, such as budding (as opposed to blebbing and zeiosis) and the inflammatory response. For cell death not by apoptosis the most satisfactory term is accidental cell death. Necrosis is commonly used but it is not appropriate, because it does not indicate a form of cell death but refers to changes secondary to cell death by any mechanism, including apoptosis. Abundant data are available on one form of accidental cell death, namely ischemic cell death, which can be considered an entity of its own, caused by failure of the ionic pumps of the plasma membrane. Because ischemic cell death (in known models) is accompanied by swelling, the name oncosis is proposed for this condition. The term oncosis (derived from ónkos, meaning swelling) was proposed in 1910 by von Reckling-hausen precisely to mean cell death with swelling. Oncosis leads to necrosis with karyolysis and stands in contrast to apoptosis, which leads to necrosis with karyorhexis and cell shrinkage. Images Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 Figure 7 Figure 8 PMID:7856735

  16. Histone deacetylase inhibitors and cell death

    PubMed Central

    Zhang, Jing; Zhong, Qing

    2014-01-01

    Histone deacetylases (HDACs) are a vast family of enzymes involved in chromatin remodeling and have crucial roles in numerous biological processes, largely through their repressive influence on transcription. In addition to modifying histones, HDACs also target many other non-histone protein substrates to regulate gene expression. Recently, HDACs have gained growing attention as HDAC-inhibiting compounds are being developed as promising cancer therapeutics. Histone deacetylase inhibitors (HDACi) have been shown to induce differentiation, cell cycle arrest, apoptosis, autophagy and necrosis in a variety of transformed cell lines. In this review, we mainly discuss how HDACi may elicit a therapeutic response to human cancers through different cell death pathways, in particular, apoptosis and autophagy. PMID:24898083

  17. Programmed Cell Death in Unicellular Phytoplankton.

    PubMed

    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. PMID:27404255

  18. Programmed Cell Death in Unicellular Phytoplankton.

    PubMed

    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.

  19. Macrophage cell death upon intracellular bacterial infection

    PubMed Central

    Lai, Xin-He; Xu, Yunsheng; Chen, Xiao-Ming; Ren, Yi

    2015-01-01

    Macrophage-pathogen interaction is a complex process and the outcome of this tag-of-war for both sides is to live or die. Without attempting to be comprehensive, this review will discuss the complexity and significance of the interaction outcomes between macrophages and some facultative intracellular bacterial pathogens as exemplified by Francisella, Salmonella, Shigella and Yersinia. Upon bacterial infection, macrophages can die by a variety of ways, such as apoptosis, autophagic cell death, necrosis, necroptosis, oncosis, pyronecrosis, pyroptosis etc, which is the focus of this review. PMID:26690967

  20. Dominant inhibitory Ras delays Sindbis virus-induced apoptosis in neuronal cells.

    PubMed Central

    Joe, A K; Ferrari, G; Jiang, H H; Liang, X H; Levine, B

    1996-01-01

    Mature neurons are more resistant than dividing cells or differentiating neurons to Sindbis virus-induced apoptotic death. Therefore, we hypothesized that mitogenic signal transduction pathways may influence susceptibility to Sindbis virus-induced apoptosis. Since Ras, a 21-kDa GTP-binding protein, plays an important role in cellular proliferation and neuronal differentiation, we investigated the effect of an inducible dominant inhibitory Ras on Sindbis virus-induced death of a rat pheochromocytoma cell line, PC12 cells. Dexamethasone induction of dominant inhibitory Ras (Ha Ras(Asn17)) expression in transfected PC12 cell lines (MMTV-M17-21 and GSrasDN6 cells) resulted in a marked delay in Sindbis virus-induced apoptosis, compared with infected, uninduced cells. The delay in death after Sindbis virus infection in induced versus uninduced PC12 cells was not associated with differences in viral titers or viral infectivity. No delay in Sindbis virus-induced apoptosis was observed in Ha Ras(Asn17)-transfected PC12 cells if dexamethasone induction was initiated less than 12 h before Sindbis virus infection or in wild-type PC12 cells infected with a chimeric Sindbis virus construct that expresses Ha Ras(Asn17). The delay in Sindbis virus-induced apoptosis in induced Ha Ras(Asn17)-transfected PC12 cells was associated with a decrease in cellular DNA synthesis as measured by 5'-bromo-2'-deoxyuridine incorporation. Thus, in PC12 cells, inducible dominant inhibitory Ras inhibits cellular proliferation and delays Sindbis virus-induced apoptosis. These findings suggest that a Ras-dependent signaling pathway is a determinant of neuronal susceptibility to Sindbis virus-induced apoptosis. PMID:8892895

  1. Cell Death and DAMPs in Acute Pancreatitis

    PubMed Central

    Kang, Rui; Lotze, Michael T; Zeh, Herbert J; Billiar, Timothy R; Tang, Daolin

    2014-01-01

    Cell death and inflammation are key pathologic responses of acute pancreatitis (AP), the leading cause of hospital admissions for gastrointestinal disorders. It is becoming increasingly clear that damage-associated molecular pattern molecules (DAMPs) play an important role in the pathogenesis of AP by linking local tissue damage to systemic inflammation syndrome. Endogenous DAMPs released from dead, dying or injured cells initiate and extend sterile inflammation via specific pattern recognition receptors. Inhibition of the release and activity of DAMPs (for example, high mobility group box 1, DNA, histones and adenosine triphosphate) provides significant protection against experimental AP. Moreover, increased serum levels of DAMPs in patients with AP correlate with disease severity. These findings provide novel insight into the mechanism, diagnosis and management of AP. DAMPs might be an attractive therapeutic target in AP. PMID:25105302

  2. Cell Death Signaling and Anticancer Therapy

    PubMed Central

    Galluzzi, Lorenzo; Vitale, Ilio; Vacchelli, Erika; Kroemer, Guido

    2011-01-01

    For a long time, it was commonly believed that efficient anticancer regimens would either trigger the apoptotic demise of tumor cells or induce a permanent arrest in the G1 phase of the cell cycle, i.e., senescence. The recent discovery that necrosis can occur in a regulated fashion and the increasingly more precise characterization of the underlying molecular mechanisms have raised great interest, as non-apoptotic pathways might be instrumental to circumvent the resistance of cancer cells to conventional, pro-apoptotic therapeutic regimens. Moreover, it has been shown that some anticancer regimens engage lethal signaling cascades that can ignite multiple oncosuppressive mechanisms, including apoptosis, necrosis, and senescence. Among these signaling pathways is mitotic catastrophe, whose role as a bona fide cell death mechanism has recently been reconsidered. Thus, anticancer regimens get ever more sophisticated, and often distinct strategies are combined to maximize efficacy and minimize side effects. In this review, we will discuss the importance of apoptosis, necrosis, and mitotic catastrophe in the response of tumor cells to the most common clinically employed and experimental anticancer agents. PMID:22655227

  3. Protection of islet cells from inflammatory cell death in vitro.

    PubMed Central

    Burkart, V; Kolb, H

    1993-01-01

    Islet cells cocultured with activated macrophages are lysed within 15 h in vitro. We showed previously that nitric oxide generated by macrophages is a major mediator of islet cell death. We have now probed several pathways to interfere with the chain of events leading to islet cell death. Scavenging of extracellular oxygen radicals by superoxide dismutase and catalase did not improve islet cell survival. Scavenging of extra- and intracellular oxygen radicals by two potent substances, citiolone and dimethyl-thiourea, also did not reduce islet cell lysis, while a lipid-soluble scavenger, probucol, provided partial protection. These findings argue against a synergistic action of nitric oxide and oxygen radicals in islet cell toxicity. The inhibition of poly(ADP-ribose)polymerase by 3-aminobenzamide significantly improved islet cell survival. Selective inhibitors of cyclooxygenase, such as indomethacin or acetylsalicylic acid, did not improve islet cell survival. Full protection was seen in the presence of NDGA, an inhibitor of lipoxygenase, and partial suppression was caused by BW755c, an inhibitor of both lipoxygenase and cyclooxygenase. We conclude that inflammatory islet cell death caused by activated macrophages involves the activation of arachidonic acid metabolism and of poly(ADP-ribose)polymerase, but that scavenging of oxygen free radicals provides little protection from lysis. PMID:8348756

  4. Sulfur dioxide induced programmed cell death in Vicia guard cells.

    PubMed

    Yi, Huilan; Yin, Jingjing; Liu, Xin; Jing, Xiuqing; Fan, Sanhong; Zhang, Hufang

    2012-04-01

    Sulfur dioxide (SO(2)) induced nuclear condensation and nuclear fragmentation and rapid loss of guard cell viability in detached epidermis of Vicia leaves at concentrations of 1 mM and higher (3 h exposure). Caspase inhibitors Z-Asp-CH(2)-DCB (0.1 mM) and TLCK (0.1 mM) markedly suppressed SO(2)-induced cell death. The typical nuclear morphological changes and the inhibition effects of caspase inhibitors suggest the activation of a programmed cell death (PCD) pathway. SO(2)-induced cell death can be blocked by either antioxidants (0.1 mM AsA or 200 U/mL CAT) or Ca(2+) antagonists (0.1mM EGTA or LaCl(3)). AsA and CAT also blocked SO(2)-induced ROS production and [Ca(2+)](cyt) increase. However, EGTA and LaCl(3) can inhibit SO(2)-induced [Ca(2+)](cyt) increase, but cannot suppress SO(2)-induced ROS production. Our results indicate that high concentrations of SO(2) induce guard cell death via a PCD pathway through ROS mediating [Ca(2+)](cyt) elevation, which causes harmful effects to plants.

  5. Xylem cell death: emerging understanding of regulation and function.

    PubMed

    Bollhöner, Benjamin; Prestele, Jakob; Tuominen, Hannele

    2012-02-01

    Evolutionary, as well as genetic, evidence suggests that vascular development evolved originally as a cell death programme that allowed enhanced movement of water in the extinct protracheophytes, and that secondary wall formation in the water-conducting cells evolved afterwards, providing mechanical support for effective long-distance transport of water. The extant vascular plants possess a common regulatory network to coordinate the different phases of xylem maturation, including secondary wall formation, cell death, and finally autolysis of the cell contents, by the action of recently identified NAC domain transcription factors. Consequently, xylem cell death is an inseparable part of the xylem maturation programme, making it difficult to uncouple cell death mechanistically from secondary wall formation, and thus identify the key factors specifically involved in regulation of cell death. Current knowledge suggests that the necessary components for xylem cell death are produced early during xylem differentiation, and cell death is prevented through the action of inhibitors and storage of hydrolytic enzymes in inactive forms in compartments such as the vacuole. Bursting of the central vacuole triggers autolytic hydrolysis of the cell contents, which ultimately leads to cell death. This cascade of events varies between the different xylem cell types. The water-transporting tracheary elements rely on a rapid cell death programme, with hydrolysis of cell contents taking place for the most part, if not entirely, after vacuolar bursting, while the xylem fibres disintegrate cellular contents at a slower pace, well before cell death. This review includes a detailed description of cell morphology, function of plant growth regulators, such as ethylene and thermospermine, and the action of hydrolytic nucleases and proteases during cell death of the different xylem cell types.

  6. Nuclear alterations associated to programmed cell death in larval salivary glands of Apis mellifera (Hymenoptera: Apidae).

    PubMed

    Silva-Zacarin, E C M; Taboga, S R; Silva de Moraes, R L M

    2008-01-01

    The silk glands of bees are a good model for the study of cell death in insects. With the objective to detect the nuclear features during glandular regression stage, larvae at the last instar and pre-pupae were collected and their silk glands were dissected and processed for ultrastructural analysis and histologically for cytochemical and imunocytochemical analysis. The results showed that the cellular nuclei exhibited characteristics of death by atypical apoptosis as well as autophagic cell death. Among the apoptosis characteristic were: nuclear strangulation with bleb formation in some nuclei, DNA fragmentation in most of the nuclei and nucleolar fragmentation. Centripetal chromatin compaction was observed in many nuclei, forming a perichromatin halo differing from typical apoptotic nuclei. With regards to the characteristics of autophagic-programmed cell death, most relevant was the delay in the collapse of many nuclei.

  7. Pyroptotic cell death defends against intracellular pathogens

    PubMed Central

    Jorgensen, Ine; Miao, Edward A

    2015-01-01

    Summary Inflammatory caspases play a central role in innate immunity by responding to cytosolic signals and initiating a twofold response. First, caspase-1 induces the activation and secretion of the two prominent pro-inflammatory cytokines, interleukin-1β (IL-1β) and IL-18. Second, either caspase-1 or caspase-11 can trigger a form of lytic, programmed cell death called pyroptosis. Pyroptosis operates to remove the replication niche of intracellular pathogens, making them susceptible to phagocytosis and killing by a secondary phagocyte. However, aberrant, systemic activation of pyroptosis in vivo may contribute to sepsis. Emphasizing the efficiency of inflammasome detection of microbial infections, many pathogens have evolved to avoid or subvert pyroptosis. This review focuses on molecular and morphological characteristics of pyroptosis and the individual inflammasomes and their contribution to defense against infection in mice and humans. PMID:25879289

  8. Caspases Connect Cell-Death Signaling to Organismal Homeostasis.

    PubMed

    Galluzzi, Lorenzo; López-Soto, Alejandro; Kumar, Sharad; Kroemer, Guido

    2016-02-16

    Some forms of regulated cell death, such as apoptosis, are precipitated by the activation of cysteine proteases of the caspase family, including caspase 8, 9, and 3. Other caspases, such as caspase 1 and 4, are well known for their pro-inflammatory functions but regulate cell death in a limited number of pathophysiological settings. Accumulating evidence suggests that the most conserved function of mammalian caspases is not to control cell death sensu stricto, but to regulate inflammatory and immune reactions to dying cells and infectious challenges. Here, we review the molecular and cellular mechanisms though which mammalian caspases connect cell-death signaling to the maintenance of organismal homeostasis.

  9. Cell death by autophagy: facts and apparent artefacts

    PubMed Central

    Denton, D; Nicolson, S; Kumar, S

    2012-01-01

    Autophagy (the process of self-digestion by a cell through the action of enzymes originating within the lysosome of the same cell) is a catabolic process that is generally used by the cell as a mechanism for quality control and survival under nutrient stress conditions. As autophagy is often induced under conditions of stress that could also lead to cell death, there has been a propagation of the idea that autophagy can act as a cell death mechanism. Although there is growing evidence of cell death by autophagy, this type of cell death, often called autophagic cell death, remains poorly defined and somewhat controversial. Merely the presence of autophagic markers in a cell undergoing death does not necessarily equate to autophagic cell death. Nevertheless, studies involving genetic manipulation of autophagy in physiological settings provide evidence for a direct role of autophagy in specific scenarios. This article endeavours to summarise these physiological studies where autophagy has a clear role in mediating the death process and discusses the potential significance of cell death by autophagy. PMID:22052193

  10. Blocking NMDA receptors delays death in rats with acute liver failure by dual protective mechanisms in kidney and brain.

    PubMed

    Cauli, Omar; González-Usano, Alba; Cabrera-Pastor, Andrea; Gimenez-Garzó, Carla; López-Larrubia, Pilar; Ruiz-Sauri, Amparo; Hernández-Rabaza, Vicente; Duszczyk, Malgorzata; Malek, Michal; Lazarewicz, Jerzy W; Carratalá, Arturo; Urios, Amparo; Miguel, Alfonso; Torregrosa, Isidro; Carda, Carmen; Montoliu, Carmina; Felipo, Vicente

    2014-06-01

    Treatment of patients with acute liver failure (ALF) is unsatisfactory and mortality remains unacceptably high. Blocking NMDA receptors delays or prevents death of rats with ALF. The underlying mechanisms remain unclear. Clarifying these mechanisms will help to design more efficient treatments to increase patient's survival. The aim of this work was to shed light on the mechanisms by which blocking NMDA receptors delays rat's death in ALF. ALF was induced by galactosamine injection. NMDA receptors were blocked by continuous MK-801 administration. Edema and cerebral blood flow were assessed by magnetic resonance. The time course of ammonia levels in brain, muscle, blood, and urine; of glutamine, lactate, and water content in brain; of glomerular filtration rate and kidney damage; and of hepatic encephalopathy (HE) and intracranial pressure was assessed. ALF reduces kidney glomerular filtration rate (GFR) as reflected by reduced inulin clearance. GFR reduction is due to both reduced renal perfusion and kidney tubular damage as reflected by increased Kim-1 in urine and histological analysis. Blocking NMDA receptors delays kidney damage, allowing transient increased GFR and ammonia elimination which delays hyperammonemia and associated changes in brain. Blocking NMDA receptors does not prevent cerebral edema or blood-brain barrier permeability but reduces or prevents changes in cerebral blood flow and brain lactate. The data show that dual protective effects of MK-801 in kidney and brain delay cerebral alterations, HE, intracranial pressure increase and death. NMDA receptors antagonists may increase survival of patients with ALF by providing additional time for liver transplantation or regeneration.

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

    PubMed

    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.

  12. Cell block eleven, looking from the "Death Row" exercise yard, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cell block eleven, looking from the "Death Row" exercise yard, facing north (note cell block fifteen to the right and cell block fourteen in the distance_ - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

  13. Light regulation of cadmium-induced cell death in Arabidopsis

    PubMed Central

    Smith, Sarah J; Wang, Yun; Slabas, Antoni R; Chivasa, Stephen

    2014-01-01

    Cadmium is an environmental pollutant with deleterious effects on both prokaryotic and eukaryotic organisms. In plants, the effects of cadmium toxicity are concentration dependent; lower doses destabilize many physiological processes and inhibit cell growth and multiplication, while higher doses evoke a more severe response that triggers activation of cell death. We recently investigated the effects of light on cadmium toxicity in Arabidopsis using a cell suspension culture system. Although not affecting the inhibitory effects on cell multiplication, we found that light is a powerful regulator of Cd-induced cell death. A very specific proteomic response, which was clearly controlled by light, preceded cell death. Here we discuss the implications of these findings and highlight similarities between the regulation of cell death triggered by Cd and fumonisin B1. We consider how both compounds could be useful tools in dissecting plant cell death signaling. PMID:24398567

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

    PubMed Central

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

    2013-01-01

    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. PMID:23633472

  15. Arabidopsis ACCELERATED CELL DEATH2 Modulates Programmed Cell DeathW⃞

    PubMed Central

    Yao, Nan; Greenberg, Jean T.

    2006-01-01

    The Arabidopsis thaliana chloroplast protein ACCELERATED CELL DEATH2 (ACD2) modulates the amount of programmed cell death (PCD) triggered by Pseudomonas syringae and protoporphyrin IX (PPIX) treatment. In vitro, ACD2 can reduce red chlorophyll catabolite, a chlorophyll derivative. We find that ACD2 shields root protoplasts that lack chlorophyll from light- and PPIX-induced PCD. Thus, chlorophyll catabolism is not obligatory for ACD2 anti-PCD function. Upon P. syringae infection, ACD2 levels and localization change in cells undergoing PCD and in their close neighbors. Thus, ACD2 shifts from being largely in chloroplasts to partitioning to chloroplasts, mitochondria, and, to a small extent, cytosol. ACD2 protects cells from PCD that requires the early mitochondrial oxidative burst. Later, the chloroplasts of dying cells generate NO, which only slightly affects cell viability. Finally, the mitochondria in dying cells have dramatically altered movements and cellular distribution. Overproduction of both ACD2 (localized to mitochondria and chloroplasts) and ascorbate peroxidase (localized to chloroplasts) greatly reduces P. syringae–induced PCD, suggesting a pro-PCD role for mitochondrial and chloroplast events. During infection, ACD2 may bind to and/or reduce PCD-inducing porphyrin-related molecules in mitochondria and possibly chloroplasts that generate reactive oxygen species, cause altered organelle behavior, and activate a cascade of PCD-inducing events. PMID:16387834

  16. Impact of delayed diagnosis time in estimating progression rates to hepatitis C virus-related cirrhosis and death.

    PubMed

    Fu, Bo; Wang, Wenbin; Shi, Xin

    2015-12-01

    Delay of the diagnosis of hepatitis C virus (HCV), and its treatment to avert cirrhosis, is often present sincethe early stage of HCV progression is latent. Current methods to determine the incubation time to HCV-related cirrhosis and the duration time from cirrhosis to subsequent events (e.g. complications or death) used to be based on the time of liver biopsy diagnosis and ignore this delay which led to an interval censoring for the first event time and a double censoring for the subsequent event time. To investigate the impact of this delay in estimating HCV progression rates and relevant estimating bias, we present a correlated two-stage progression model for delayed diagnosis time and fit the developed model to the previously studied hepatitis C cohort data from Edinburgh. Our analysis shows that taking the delayed diagnosis into account gives a mildly different estimate of progression rate to cirrhosis and significantly lower estimated progression rate to HCV-related death in comparison with conventional modelling. We also find that when the delay increases, the bias in estimating progression increases significantly.

  17. Programmed cell death for defense against anomaly and tumor formation

    SciTech Connect

    Kondo, Sohei; Norimura, Toshiyuki; Nomura, Taisei

    1995-12-31

    Cell death after exposure to low-level radiation is often considered evidence that radiation is poisonous, however small the dose. Evidence has been accumulating to support the notion that cell death after low-level exposure to radiation results from activation of suicidal genes {open_quote}programmed cell death{close_quote} or {open_quote}apoptosis{close_quote} - for the health of the whole body. This paper gives experimental evidence that embryos of fruit flies and mouse fetuses have potent defense mechanisms against teratogenic or tumorigenic injury caused by radiation and carcinogens, which function through programmed cell death.

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

    PubMed Central

    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 microarray analysis of H2O2-induced cell death have begun to unravel the complexity of the H2O2 network. This review also describes a novel link between H2O2 and sphingolipids, two signals that can interplay and regulate plant cell death. PMID:15631987

  19. Death of mitochondria during programmed cell death of leaf mesophyll cells.

    PubMed

    Selga, Tūrs; Selga, Maija; Pāvila, Vineta

    2005-12-01

    The role of plant mitochondria in the programmed cell death (PCD) is widely discussed. However, spectrum and sequence of mitochondrial structural changes during different types of PCD in leaves are poorly described. Pea, cucumber and rye plants were grown under controlled growing conditions. A part of them were sprinkled with ethylene releaser to accelerate cell death. During yellowing the palisade parenchyma mitochondria were attracted to nuclear envelope. Mitochondrial matrix became electron translucent. Mitochondria entered vacuole by invagination of tonoplast and formed multivesicular bodies. Ethephon treatment increased the frequency of sticking of mitochondria to the nuclear envelope or chloroplasts and peroxisomes. Mitochondria divided by different mechanisms and became enclosed in Golgi and ER derived authopagic vacuoles or in the central vacuole. Several fold increase of the diameter of cristae became typical. In all cases mitochondria were attached to nuclear envelope. It can be considered as structural mechanism of promoting of PCD.

  20. The endoplasmic reticulum binding protein BiP displays dual function in modulating cell death events.

    PubMed

    Carvalho, Humberto H; Silva, Priscila A; Mendes, Giselle C; Brustolini, Otávio J B; Pimenta, Maiana R; Gouveia, Bianca C; Valente, Maria Anete S; Ramos, Humberto J O; Soares-Ramos, Juliana R L; Fontes, Elizabeth P B

    2014-02-01

    The binding protein (BiP) has been demonstrated to participate in innate immunity and attenuate endoplasmic reticulum- and osmotic stress-induced cell death. Here, we employed transgenic plants with manipulated levels of BiP to assess whether BiP also controlled developmental and hypersensitive programmed cell death (PCD). Under normal conditions, the BiP-induced transcriptome revealed a robust down-regulation of developmental PCD genes and an up-regulation of the genes involved in hypersensitive PCD triggered by nonhost-pathogen interactions. Accordingly, the BiP-overexpressing line displayed delayed leaf senescence under normal conditions and accelerated hypersensitive response triggered by Pseudomonas syringae pv tomato in soybean (Glycine max) and tobacco (Nicotiana tabacum), as monitored by measuring hallmarks of PCD in plants. The BiP-mediated delay of leaf senescence correlated with the attenuation of N-rich protein (NRP)-mediated cell death signaling and the inhibition of the senescence-associated activation of the unfolded protein response (UPR). By contrast, under biological activation of salicylic acid (SA) signaling and hypersensitive PCD, BiP overexpression further induced NRP-mediated cell death signaling and antagonistically inhibited the UPR. Thus, the SA-mediated induction of NRP cell death signaling occurs via a pathway distinct from UPR. Our data indicate that during the hypersensitive PCD, BiP positively regulates the NRP cell death signaling through a yet undefined mechanism that is activated by SA signaling and related to ER functioning. By contrast, BiP's negative regulation of leaf senescence may be linked to its capacity to attenuate the UPR activation and NRP cell death signaling. Therefore, BiP can function either as a negative or positive modulator of PCD events. PMID:24319082

  1. α-Synuclein and neuronal cell death

    PubMed Central

    Cookson, Mark R

    2009-01-01

    α-Synuclein is a small protein that has special relevance for understanding Parkinson disease and related disorders. Not only is α-synuclein found in Lewy bodies characteristic of Parkinson disease, but also mutations in the gene for α-synuclein can cause an inherited form of Parkinson disease and expression of normal α-synuclein can increase the risk of developing Parkinson disease in sporadic, or non-familial, cases. Both sporadic and familial Parkinson disease are characterized by substantial loss of several groups of neurons, including the dopaminergic cells of the substantia nigra that are the target of most current symptomatic therapies. Therefore, it is predicted that α-synuclein, especially in its mutant forms or under conditions where its expression levels are increased, is a toxic protein in the sense that it is associated with an increased rate of neuronal cell death. This review will discuss the experimental contexts in which α-synuclein has been demonstrated to be toxic. I will also outline what is known about the mechanisms by which α-synuclein triggers neuronal damage, and identify some of the current gaps in our knowledge about this subject. Finally, the therapeutic implications of toxicity of α-synuclein will be discussed. PMID:19193223

  2. Photoreceptor cell death and rescue in retinal detachment and degenerations

    PubMed Central

    Murakami, Yusuke; Notomi, Shoji; Hisatomi, Toshio; Nakazawa, Toru; Ishibashi, Tatsuro; Miller, Joan W.; Vavvas, Demetrios G.

    2013-01-01

    Photoreceptor cell death is the ultimate cause of vision loss in various retinal disorders, including retinal detachment (RD). Photoreceptor cell death has been thought to occur mainly through apoptosis, which is the most characterized form of programmed cell death. The caspase family of cysteine proteases plays a central role for inducing apoptosis, and in experimental models of RD, dying photoreceptor cells exhibit caspase activation; however, there is a paradox that caspase inhibition alone does not provide a sufficient protection against photoreceptor cell loss, suggesting that other mechanisms of cell death are involved. Recent accumulating evidence demonstrates that non-apoptotic forms of cell death, such as autophagy and necrosis, are also regulated by specific molecular machinery, such as those mediated by autophagy-related proteins and receptor-interacting protein kinases, respectively. Here we summarize the current knowledge of cell death signaling and its roles in photoreceptor cell death after RD and other retinal degenerative diseases. A body of studies indicate that not only apoptotic but also autophagic and necrotic signaling are involved in photoreceptor cell death, and that combined targeting of these pathways may be an effective neuroprotective strategy for retinal diseases associated with photoreceptor cell loss. PMID:23994436

  3. Modulation of programmed cell death by medicinal plants.

    PubMed

    Thatte, U; Bagadey, S; Dahanukar, S

    2000-02-01

    Programmed cell death (apoptosis), a form of cell death, described by Kerr and Wyllie some 20 years ago, has generated considerable interest in recent years. The mechanisms by which this mode of cell death (seen both in animal and plant cells), takes place have been examined in detail. Extracellular signals and intracellular events have been elaborated. Of interest to the clinician, is the concentrated effort to study pharmacological modulation of programmed cell death. The attempt to influence the natural phenomenon of programmed cell death stems from the fact that it is reduced (like in cancer) or increased (like in neurodegenerative diseases) in several clinical situations. Thus, chemicals that can modify programmed cell death are likely to be potentially useful drugs. From foxglove, which gave digitalis to the Pacific Yew from which came taxol, plants have been a source of research material for useful drugs. Recently, a variety of plant extracts have been investigated for their ability to influence the apoptotic process. This article discusses some of the interesting data. The ability of plants to influence programmed cell death in cancerous cells in an attempt to arrest their proliferation has been the topic of much research. Various cell-lines like HL60, human hepatocellular carcinoma cell line (KIM-1), a cholangiocarcinoma cell-line (KMC-1), B-cell hybridomas, U937 a monocytic cell-line, HeLa cells, human lymphoid leukemia (MOLT-4B) cells and K562 cells have been studied. The agents found to induce programmed cell death (measured either morphologically or flow cytometrically) included extracts of plants like mistletoe and Semicarpus anacardium. Isolated compounds like bryonolic acid (from Trichosanthes kirilowii var. Japonica, crocin (from saffron) and allicin (from Allium sativum) have also been found to induce programmed cell death and therefore arrest proliferation. Even Chinese herbal medicine "Sho-saiko-to" induces programmed cell death in selected

  4. Bacterial programmed cell death of cerebral endothelial cells involves dual death pathways

    PubMed Central

    Bermpohl, Daniela; Halle, Annett; Freyer, Dorette; Dagand, Emilie; Braun, Johann S.; Bechmann, Ingo; Schröder, Nicolas W.J.; Weber, Joerg R.

    2005-01-01

    Major barriers separating the blood from tissue compartments in the body are composed of endothelial cells. Interaction of bacteria with such barriers defines the course of invasive infections, and meningitis has served as a model system to study endothelial cell injury. Here we report the impressive ability of Streptococcus pneumoniae, clinically one of the most important pathogens, to induce 2 morphologically distinct forms of programmed cell death (PCD) in brain-derived endothelial cells. Pneumococci and the major cytotoxins H202 and pneumolysin induce apoptosis-like PCD independent of TLR2 and TLR4. On the other hand, pneumococcal cell wall, a major proinflammatory component, causes caspase-driven classical apoptosis that is mediated through TLR2. These findings broaden the scope of bacterial-induced PCD, link these effects to innate immune TLRs, and provide insight into the acute and persistent phases of damage during meningitis. PMID:15902310

  5. Cell death programs in Yersinia immunity and pathogenesis

    PubMed Central

    Philip, Naomi H.; Brodsky, Igor E.

    2012-01-01

    Cell death plays a central role in host-pathogen interactions, as it can eliminate the pathogen's replicative niche and provide pro-inflammatory signals necessary for an effective immune response; conversely, cell death can allow pathogens to eliminate immune cells and evade anti-microbial effector mechanisms. In response to developmental signals or cell-intrinsic stresses, the executioner caspases-3 and -7 mediate apoptotic cell death, which is generally viewed as immunologically silent or immunosuppressive. A proinflammatory form of cell death that requires caspase-1, termed pyroptosis, is activated in response to microbial products within the host cytosol or disruption of cellular membranes by microbial pathogens. Infection by the bacterial pathogen Yersinia has features of both apoptosis and pyroptosis. Cell death and caspase-1 processing in Yersinia-infected cells occur in response to inhibition of NF-κB and MAPK signaling by the Yersinia virulence factor YopJ. However, the molecular basis of YopJ-induced cell death, and the role of different death pathways in anti-Yersinia immune responses remain enigmatic. Here, we discuss the role that cell death may play in inducing specific pro-inflammatory signals that shape innate and adaptive immune responses against Yersinia infection. PMID:23226685

  6. Cell-in-Cell Death Is Not Restricted by Caspase-3 Deficiency in MCF-7 Cells

    PubMed Central

    Wang, Shan; He, Meifang; Li, Linmei; Liang, Zhihua; Zou, Zehong

    2016-01-01

    Purpose Cell-in-cell structures are created by one living cell entering another homotypic or heterotypic living cell, which usually leads to the death of the internalized cell, specifically through caspase-dependent cell death (emperitosis) or lysosome-dependent cell death (entosis). Although entosis has attracted great attention, its occurrence is controversial, because one cell line used in its study (MCF-7) is deficient in caspase-3. Methods We investigated this issue using MCF-7 and A431 cell lines, which often display cell-in-cell invasion, and have different levels of caspase-3 expression. Cell-in-cell death morphology, microstructures, and signaling pathways were compared in the two cell lines. Results Our results confirmed that MCF-7 cells are caspase-3 deficient with a partial deletion in the CASP-3 gene. These cells underwent cell death that lacked typical apoptotic properties after staurosporine treatment, whereas caspase-3-sufficient A431 cells displayed typical apoptosis. The presence of caspase-3 was related neither to the lysosome-dependent nor to the caspase-dependent cell-in-cell death pathway. However, the existence of caspase-3 was associated with a switch from lysosome-dependent cell-in-cell death to the apoptotic cell-in-cell death pathway during entosis. Moreover, cellular hypoxia, mitochondrial swelling, release of cytochrome C, and autophagy were observed in internalized cells during entosis. Conclusion The occurrence of caspase-independent entosis is not a cell-specific process. In addition, entosis actually represents a cellular self-repair system, functioning through autophagy, to degrade damaged mitochondria resulting from cellular hypoxia in cell-in-cell structures. However, sustained autophagy-associated signal activation, without reduction in cellular hypoxia, eventually leads to lysosome-dependent intracellular cell death. PMID:27721872

  7. High LET radiation enhances nocodazole Induced cell death in HeLa cells through mitotic catastrophe and apoptosis.

    PubMed

    Li, Ping; Zhou, Libin; Dai, Zhongying; Jin, Xiaodong; Liu, Xinguo; Matsumoto, Yoshitaka; Furusawa, Yoshiya; Li, Qiang

    2011-01-01

    To understand how human tumor cells respond to the combined treatment with nocodazole and high LET radiation, alterations in cell cycle, mitotic disturbances and cell death were investigated in the present study. Human cervix carcinoma HeLa cells were exposed to nocodazole for 18 h immediately followed by high LET iron ion irradiation and displayed a sequence of events leading to DNA damages, mitotic aberrations, interphase restitution and endocycle as well as cell death. A prolonged mitotic arrest more than 10 h was observed following nocodazole exposure, no matter the irradiation was present or not. The occurrence of mitotic slippage following the mitotic arrest was only drug-dependent and the irradiation did not accelerate it. The amount of polyploidy cells was increased following mitotic slippage. No detectable G(2) or G(1) arrest was observed in cells upon the combined treatment and the cells reentered the cell cycle still harboring unrepaired cellular damages. This premature entry caused an increase of multipolar mitotic spindles and amplification of centrosomes, which gave rise to lagging chromosomal material, failure of cytokinesis and polyploidization. These mitotic disturbances and their outcomes confirmed the incidence of mitotic catastrophe and delayed apoptotic features displayed by TUNEL method after the combined treatment. These results suggest that the addition of high-LET iron ion irradiation to nocodazole enhanced mitotic catastrophe and delayed apoptosis in HeLa cells. These might be important cell death mechanisms involved in tumor cells in response to the treatment of antimitotic drug combined with high LET radiation.

  8. Cell death by necrosis, a regulated way to go.

    PubMed

    Henriquez, Mauricio; Armisén, Ricardo; Stutzin, Andrés; Quest, Andrew F G

    2008-05-01

    Apoptosis is a programmed form of cell death with well-defined morphological traits that are often associated with activation of caspases. More recently evidence has become available demonstrating that upon caspase inhibition alternative programs of cell death are executed, including ones with features characteristic of necrosis. These findings have changed our view of necrosis as a passive and essentially accidental form of cell death to that of an active, regulated and controllable process. Also necrosis has now been observed in parallel with, rather than as an alternative pathway to, apoptosis. Thus, cell death responses are extremely flexible despite being programmed. In this review, some of the hallmarks of different programmed cell death modes have been highlighted before focusing the discussion on necrosis. Obligatory events associated with this form of cell death include uncompensated cell swelling and related changes at the plasma membrane. In this context, representatives of the transient receptor channel family and their regulation are discussed. Also mechanisms that lead to execution of the necrotic cell death program are highlighted. Emphasis is laid on summarizing our understanding of events that permit switching between cell death modes and how they connect to necrosis. Finally, potential implications for the treatment of some disease states are mentioned. PMID:18473819

  9. Actin as Deathly Switch? How Auxin Can Suppress Cell-Death Related Defence

    PubMed Central

    Chang, Xiaoli; Riemann, Michael; Liu, Qiong; Nick, Peter

    2015-01-01

    Plant innate immunity is composed of two layers – a basal immunity, and a specific effector-triggered immunity, which is often accompanied by hypersensitive cell death. Initiation of cell death depends on a complex network of signalling pathways. The phytohormone auxin as central regulator of plant growth and development represents an important component for the modulation of plant defence. In our previous work, we showed that cell death is heralded by detachment of actin from the membrane. Both, actin response and cell death, are triggered by the bacterial elicitor harpin in grapevine cells. In this study we investigated, whether harpin-triggered actin bundling is necessary for harpin-triggered cell death. Since actin organisation is dependent upon auxin, we used different auxins to suppress actin bundling. Extracellular alkalinisation and transcription of defence genes as the basal immunity were examined as well as cell death. Furthermore, organisation of actin was observed in response to pharmacological manipulation of reactive oxygen species and phospholipase D. We find that induction of defence genes is independent of auxin. However, auxin can suppress harpin-induced cell death and also counteract actin bundling. We integrate our findings into a model, where harpin interferes with an auxin dependent pathway that sustains dynamic cortical actin through the activity of phospholipase D. The antagonism between growth and defence is explained by mutual competition for signal molecules such as superoxide and phosphatidic acid. Perturbations of the auxin-actin pathway might be used to detect disturbed integrity of the plasma membrane and channel defence signalling towards programmed cell death. PMID:25933033

  10. Transcranial Doppler ultrasound in the diagnosis of brain death. Is it useful or does it delay the diagnosis?

    PubMed

    Escudero, D; Otero, J; Quindós, B; Viña, L

    2015-05-01

    Transcranial Doppler ultrasound is able to demonstrate cerebral circulatory arrest associated to brain death, being especially useful in sedated patients, or in those in which complete neurological exploration is not possible. Transcranial Doppler ulstrasound is a portable, noninvasive and high-availability technique. Among its limitations, mention must be made of the absence of acoustic windows and false-negative cases. In patients clinically diagnosed with brain death, with open skulls or with anoxia as the cause of death, cerebral blood flow can be observed by ultrasound, since cerebral circulatory arrest is not always synchronized to the clinical diagnosis. The diagnostic rate is therefore time-dependent, and this fact that must be recognized in order to avoid delays in death certification. Despite its limitations, transcranial Doppler ulstrasound helps solve common diagnostic problems, avoids the unnecessary consumption of resources, and can optimize organ harvesting for transplantation.

  11. Transcranial Doppler ultrasound in the diagnosis of brain death. Is it useful or does it delay the diagnosis?

    PubMed

    Escudero, D; Otero, J; Quindós, B; Viña, L

    2015-05-01

    Transcranial Doppler ultrasound is able to demonstrate cerebral circulatory arrest associated to brain death, being especially useful in sedated patients, or in those in which complete neurological exploration is not possible. Transcranial Doppler ulstrasound is a portable, noninvasive and high-availability technique. Among its limitations, mention must be made of the absence of acoustic windows and false-negative cases. In patients clinically diagnosed with brain death, with open skulls or with anoxia as the cause of death, cerebral blood flow can be observed by ultrasound, since cerebral circulatory arrest is not always synchronized to the clinical diagnosis. The diagnostic rate is therefore time-dependent, and this fact that must be recognized in order to avoid delays in death certification. Despite its limitations, transcranial Doppler ulstrasound helps solve common diagnostic problems, avoids the unnecessary consumption of resources, and can optimize organ harvesting for transplantation. PMID:25583044

  12. Triggering Death of Adherent Cells with Ultraviolet Radiation.

    PubMed

    Crowley, Lisa C; Waterhouse, Nigel J

    2016-01-01

    Ultraviolet (UV) radiation is a convenient stimulus for triggering cell death that is available in most laboratories. We use a Stratalinker UV cross-linker because it is a safe, cheap, reliable, consistent, and easily controlled source of UV irradiation. This protocol describes using a Stratalinker to trigger UV-induced death of HeLa cells. PMID:27371593

  13. Increased Mitochondrial Activity in Anthrax-Induced Cell Death

    PubMed Central

    Li, Chi

    2009-01-01

    Pathogenesis of anthrax lethal toxin (LT) is attributed to its ability to cause death of infected cells. New work has demonstrated that increase of mitochondrial F1F0 ATPase activity and subsequent depletion of cellular ATP level are critical early events during LT-induced cell death. PMID:26124679

  14. Short-term and delayed effects of mother death on calf mortality in Asian elephants

    PubMed Central

    Mar, Khyne U.; Lummaa, Virpi

    2016-01-01

    Long-lived, highly social species with prolonged offspring dependency can show long postreproductive periods. The Mother hypothesis proposes that a need for extended maternal care of offspring together with increased maternal mortality risk associated with old age select for such postreproductive survival, but tests in species with long postreproductive periods, other than humans and marine mammals, are lacking. Here, we investigate the Mother hypothesis with longitudinal data on Asian elephants from timber camps of Myanmar 1) to determine the costs of reproduction on female age-specific mortality risk within 1 year after calving and 2) to quantify the effects of mother loss on calf survival across development. We found that older females did not show an increased immediate mortality risk after calving. Calves had a 10-fold higher mortality risk in their first year if they lost their mother, but this decreased with age to only a 1.1-fold higher risk in the fifth year. We also detected delayed effects of maternal death: calves losing their mother during early ages still suffered from increased mortality risk at ages 3–4 and during adolescence but such effects were weaker in magnitude. Consequently, the Mother hypothesis could account for the first 5 years of postreproductive survival, but there were no costs of continued reproduction on the immediate maternal mortality risk. However, the observed postreproductive lifespan of females surviving to old age commonly exceeds 5 years in Asian elephants, and further studies are thus needed to determine selection for (postreproductive) lifespan in elephants and other comparably long-lived species. PMID:26792972

  15. TRAIL restores DCA/metformin-mediated cell death in hypoxia.

    PubMed

    Hong, Sung-Eun; Kim, Chang Soon; An, Sungkwan; Kim, Hyun-Ah; Hwang, Sang-Gu; Song, Jie-Young; Lee, Jin Kyung; Hong, Jungil; Kim, Jong-Il; Noh, Woo Chul; Jin, Hyeon-Ok; Park, In-Chul

    2016-09-23

    Previous studies have shown that hypoxia can reverse DCA/metformin-induced cell death in breast cancer cells. Therefore, targeting hypoxia is necessary for therapies targeting cancer metabolism. In the present study, we found that TRAIL can overcome the effect of hypoxia on the cell death induced by treatment of DCA and metformin in breast cancer cells. Unexpectedly, DR5 is upregulated in the cells treated with DCA/metformin, and sustained under hypoxia. Blocking DR5 by siRNA inhibited DCA/metformin/TRAIL-induced cell death, indicating that DR5 upregulation plays an important role in sensitizing cancer cells to TRAIL-induced cell death. Furthermore, we found that activation of JNK and c-Jun is responsible for upregulation of DR5 induced by DCA/metformin. These findings support the potential application of combining TRAIL and metabolism-targeting drugs in the treatment of cancers under hypoxia. PMID:27569287

  16. The convergence of radiation and immunogenic cell death signaling pathways

    PubMed Central

    Golden, Encouse B.; Pellicciotta, Ilenia; Demaria, Sandra; Barcellos-Hoff, Mary H.; Formenti, Silvia C.

    2012-01-01

    Ionizing radiation (IR) triggers programmed cell death in tumor cells through a variety of highly regulated processes. Radiation-induced tumor cell death has been studied extensively in vitro and is widely attributed to multiple distinct mechanisms, including apoptosis, necrosis, mitotic catastrophe (MC), autophagy, and senescence, which may occur concurrently. When considering tumor cell death in the context of an organism, an emerging body of evidence suggests there is a reciprocal relationship in which radiation stimulates the immune system, which in turn contributes to tumor cell kill. As a result, traditional measurements of radiation-induced tumor cell death, in vitro, fail to represent the extent of clinically observed responses, including reductions in loco-regional failure rates and improvements in metastases free and overall survival. Hence, understanding the immunological responses to the type of radiation-induced cell death is critical. In this review, the mechanisms of radiation-induced tumor cell death are described, with particular focus on immunogenic cell death (ICD). Strategies combining radiotherapy with specific chemotherapies or immunotherapies capable of inducing a repertoire of cancer specific immunogens might potentiate tumor control not only by enhancing cell kill but also through the induction of a successful anti-tumor vaccination that improves patient survival. PMID:22891162

  17. Capsaicin induces immunogenic cell death in human osteosarcoma cells

    PubMed Central

    Jin, Tao; Wu, Hongyan; Wang, Yanlin; Peng, Hao

    2016-01-01

    Immunogenic cell death (ICD) is characterized by the early surface exposure of calreticulin (CRT). As a specific signaling molecule, CRT on the surface of apoptotic tumor cells mediates the recognition and phagocytosis of tumor cells by antigen presenting cells. To date, only a small quantity of anti-cancer chemicals have been found to induce ICD, therefore it is clinically important to identify novel chemicals that may induce ICD. The purpose of the present study is to explore the function of capsaicin in inducing ICD. In the current study, MTT assays were used to examine the growth inhibiting effects of MG-63 cells when they were treated with capsaicin or cisplatin. Mitochondrial membrane potential and western blot analysis were used to investigate capsaicin- and cisplatin-induced apoptosis. In addition, the effects of capsaicin and cisplatin were evaluated for their abilities in inducing calreticulin membrane translocation and mediating ICD in human osteosarcoma cells (MG-63). The results demonstrated that capsaicin and cisplatin can induce the apoptosis of MG-63 cells. However, only capsaicin induced a rapid translocation of CRT from the intracellular space to the cell surface. Treatment with capsaicin increased phagocytosis of MG-63 cells by dendritic cells (DCs), and these MG-63-loaded DCs could efficiently stimulate the secretion of IFN-γ by lymphocytes. These results identify capsaicin as an anti-cancer agent capable of inducing ICD in human osteosarcoma cells in vitro. PMID:27446273

  18. [Programmed cell death: history and future of a concept].

    PubMed

    Lockshin, Richard A

    2005-01-01

    Cell death was observed and understood since the 19th century, but there was no experimental examination until the mid-20th century. Beginning in the 1960's, several laboratories demonstrated that cell death was biologically controlled (programmed) and that the morphology was common and not readily explained (apoptosis). By 1990 the genetic basis of programmed cell death had been established and the first components of the cell death machinery (caspase 3, bcl-2 and Fas) had been identified, sequenced, and recognized as highly conserved in evolution. The rapid development of the field has given us substantial understanding of how cell death is achieved. However, capitalizing on our knowledge for therapeutic purposes requires us to learn much more about how a cell commits to death, as well as recognizing that apoptosis may be the most common and efficient means of death, but that there are alternative pathways that can result in cell death even when the conventional pathway is blocked. Interestingly enough, many of the arguments and missteps in the history of the field were anticipated by Claude Bernard, and his warnings and recommendations remain valid today.

  19. Nitric oxide and cell death in liver cancer cells.

    PubMed

    Muntané, Jordi; De la Rosa, Angel J; Marín, Luís M; Padillo, Francisco J

    2013-05-01

    Nitric oxide (NO) is a lipophillic, highly diffusible, and short-lived physiological messenger which regulates a variety of physiopathological responses. NO may exert its cellular action through cGMP-dependent and cGMP-independent pathways which includes different postranslational modifications. The effect of NO in cancer depends on the activity and localization of NOS isoforms, concentration and duration of NO exposure, cellular sensitivity, and hypoxia/re-oxygenation process. NO regulates critical factors such as the hypoxia inducible factor-1 (HIF-1) and p53 generally leading to growth arrest, apoptosis or adaptation. NO sensitizes hepatoma cells to chemotherapeutic compounds probably through increased p53 and cell death receptor expressions.

  20. Synchronized renal tubular cell death involves ferroptosis.

    PubMed

    Linkermann, Andreas; Skouta, Rachid; Himmerkus, Nina; Mulay, Shrikant R; Dewitz, Christin; De Zen, Federica; Prokai, Agnes; Zuchtriegel, Gabriele; Krombach, Fritz; Welz, Patrick-Simon; Weinlich, Ricardo; Vanden Berghe, Tom; Vandenabeele, Peter; Pasparakis, Manolis; Bleich, Markus; Weinberg, Joel M; Reichel, Christoph A; Bräsen, Jan Hinrich; Kunzendorf, Ulrich; Anders, Hans-Joachim; Stockwell, Brent R; Green, Douglas R; Krautwald, Stefan

    2014-11-25

    Receptor-interacting protein kinase 3 (RIPK3)-mediated necroptosis is thought to be the pathophysiologically predominant pathway that leads to regulated necrosis of parenchymal cells in ischemia-reperfusion injury (IRI), and loss of either Fas-associated protein with death domain (FADD) or caspase-8 is known to sensitize tissues to undergo spontaneous necroptosis. Here, we demonstrate that renal tubules do not undergo sensitization to necroptosis upon genetic ablation of either FADD or caspase-8 and that the RIPK1 inhibitor necrostatin-1 (Nec-1) does not protect freshly isolated tubules from hypoxic injury. In contrast, iron-dependent ferroptosis directly causes synchronized necrosis of renal tubules, as demonstrated by intravital microscopy in models of IRI and oxalate crystal-induced acute kidney injury. To suppress ferroptosis in vivo, we generated a novel third-generation ferrostatin (termed 16-86), which we demonstrate to be more stable, to metabolism and plasma, and more potent, compared with the first-in-class compound ferrostatin-1 (Fer-1). Even in conditions with extraordinarily severe IRI, 16-86 exerts strong protection to an extent which has not previously allowed survival in any murine setting. In addition, 16-86 further potentiates the strong protective effect on IRI mediated by combination therapy with necrostatins and compounds that inhibit mitochondrial permeability transition. Renal tubules thus represent a tissue that is not sensitized to necroptosis by loss of FADD or caspase-8. Finally, ferroptosis mediates postischemic and toxic renal necrosis, which may be therapeutically targeted by ferrostatins and by combination therapy. PMID:25385600

  1. Synchronized renal tubular cell death involves ferroptosis

    PubMed Central

    Skouta, Rachid; Himmerkus, Nina; Mulay, Shrikant R.; Dewitz, Christin; De Zen, Federica; Prokai, Agnes; Zuchtriegel, Gabriele; Krombach, Fritz; Welz, Patrick-Simon; Weinlich, Ricardo; Vanden Berghe, Tom; Vandenabeele, Peter; Pasparakis, Manolis; Bleich, Markus; Weinberg, Joel M.; Reichel, Christoph A.; Bräsen, Jan Hinrich; Kunzendorf, Ulrich; Anders, Hans-Joachim; Stockwell, Brent R.; Green, Douglas R.; Krautwald, Stefan

    2014-01-01

    Receptor-interacting protein kinase 3 (RIPK3)-mediated necroptosis is thought to be the pathophysiologically predominant pathway that leads to regulated necrosis of parenchymal cells in ischemia–reperfusion injury (IRI), and loss of either Fas-associated protein with death domain (FADD) or caspase-8 is known to sensitize tissues to undergo spontaneous necroptosis. Here, we demonstrate that renal tubules do not undergo sensitization to necroptosis upon genetic ablation of either FADD or caspase-8 and that the RIPK1 inhibitor necrostatin-1 (Nec-1) does not protect freshly isolated tubules from hypoxic injury. In contrast, iron-dependent ferroptosis directly causes synchronized necrosis of renal tubules, as demonstrated by intravital microscopy in models of IRI and oxalate crystal-induced acute kidney injury. To suppress ferroptosis in vivo, we generated a novel third-generation ferrostatin (termed 16-86), which we demonstrate to be more stable, to metabolism and plasma, and more potent, compared with the first-in-class compound ferrostatin-1 (Fer-1). Even in conditions with extraordinarily severe IRI, 16-86 exerts strong protection to an extent which has not previously allowed survival in any murine setting. In addition, 16-86 further potentiates the strong protective effect on IRI mediated by combination therapy with necrostatins and compounds that inhibit mitochondrial permeability transition. Renal tubules thus represent a tissue that is not sensitized to necroptosis by loss of FADD or caspase-8. Finally, ferroptosis mediates postischemic and toxic renal necrosis, which may be therapeutically targeted by ferrostatins and by combination therapy. PMID:25385600

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

    NASA Technical Reports Server (NTRS)

    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.

  3. Programmed Cell Death and Complexity in Microbial Systems.

    PubMed

    Durand, Pierre M; Sym, Stuart; Michod, Richard E

    2016-07-11

    Programmed cell death (PCD) is central to organism development and for a long time was considered a hallmark of multicellularity. Its discovery, therefore, in unicellular organisms presents compelling questions. Why did PCD evolve? What is its ecological effect on communities? To answer these questions, one is compelled to consider the impacts of PCD beyond the cell, for death obviously lowers the fitness of the cell. Here, we examine the ecological effects of PCD in different microbial scenarios and conclude that PCD can increase biological complexity. In mixed microbial communities, the mode of death affects the microenvironment, impacting the interactions between taxa. Where the population comprises groups of relatives, death has a more explicit effect. Death by lysis or other means can be harmful, while PCD can evolve by providing advantages to relatives. The synchronization of death between individuals suggests a group level property is being maintained and the mode of death also appears to have had an impact during the origin of multicellularity. PCD can result in the export of fitness from the cell to the group level via re-usable resources and PCD may also provide a mechanism for how groups beget new groups comprising kin. Furthermore, PCD is a means for solving a central problem of group living - the toxic effects of death - by making resources in dying cells beneficial to others. What emerges from the data reviewed here is that while PCD carries an obvious cost to the cell, it can be a driver of complexity in microbial communities. PMID:27404254

  4. Sorafenib-induced defective autophagy promotes cell death by necroptosis.

    PubMed

    Kharaziha, Pedram; Chioureas, Dimitris; Baltatzis, George; Fonseca, Pedro; Rodriguez, Patricia; Gogvadze, Vladimir; Lennartsson, Lena; Björklund, Ann-Charlotte; Zhivotovsky, Boris; Grandér, Dan; Egevad, Lars; Nilsson, Sten; Panaretakis, Theocharis

    2015-11-10

    Autophagy is one of the main cytoprotective mechanisms that cancer cells deploy to withstand the cytotoxic stress and survive the lethal damage induced by anti-cancer drugs. However, under specific conditions, autophagy may, directly or indirectly, induce cell death. In our study, treatment of the Atg5-deficient DU145 prostate cancer cells, with the multi-tyrosine kinase inhibitor, sorafenib, induces mitochondrial damage, autophagy and cell death. Molecular inhibition of autophagy by silencing ULK1 and Beclin1 rescues DU145 cells from cell death indicating that, in this setting, autophagy promotes cell death. Re-expression of Atg5 restores the lipidation of LC3 and rescues DU145 and MEF atg5-/- cells from sorafenib-induced cell death. Despite the lack of Atg5 expression and LC3 lipidation, DU145 cells form autophagosomes as demonstrated by transmission and immuno-electron microscopy, and the formation of LC3 positive foci. However, the lack of cellular content in the autophagosomes, the accumulation of long-lived proteins, the presence of GFP-RFP-LC3 positive foci and the accumulated p62 protein levels indicate that these autophagosomes may not be fully functional. DU145 cells treated with sorafenib undergo a caspase-independent cell death that is inhibited by the RIPK1 inhibitor, necrostatin-1. Furthermore, treatment with sorafenib induces the interaction of RIPK1 with p62, as demonstrated by immunoprecipitation and a proximity ligation assay. Silencing of p62 decreases the RIPK1 protein levels and renders necrostatin-1 ineffective in blocking sorafenib-induced cell death. In summary, the formation of Atg5-deficient autophagosomes in response to sorafenib promotes the interaction of p62 with RIPK leading to cell death by necroptosis. PMID:26416459

  5. Sorafenib-induced defective autophagy promotes cell death by necroptosis

    PubMed Central

    Kharaziha, Pedram; Chioureas, Dimitris; Baltatzis, George; Fonseca, Pedro; Rodriguez, Patricia; Gogvadze, Vladimir; Lennartsson, Lena; Björklund, Ann-Charlotte; Zhivotovsky, Boris; Grandér, Dan; Egevad, Lars; Nilsson, Sten; Panaretakis, Theocharis

    2015-01-01

    Autophagy is one of the main cytoprotective mechanisms that cancer cells deploy to withstand the cytotoxic stress and survive the lethal damage induced by anti-cancer drugs. However, under specific conditions, autophagy may, directly or indirectly, induce cell death. In our study, treatment of the Atg5-deficient DU145 prostate cancer cells, with the multi-tyrosine kinase inhibitor, sorafenib, induces mitochondrial damage, autophagy and cell death. Molecular inhibition of autophagy by silencing ULK1 and Beclin1 rescues DU145 cells from cell death indicating that, in this setting, autophagy promotes cell death. Re-expression of Atg5 restores the lipidation of LC3 and rescues DU145 and MEF atg5−/− cells from sorafenib-induced cell death. Despite the lack of Atg5 expression and LC3 lipidation, DU145 cells form autophagosomes as demonstrated by transmission and immuno-electron microscopy, and the formation of LC3 positive foci. However, the lack of cellular content in the autophagosomes, the accumulation of long-lived proteins, the presence of GFP-RFP-LC3 positive foci and the accumulated p62 protein levels indicate that these autophagosomes may not be fully functional. DU145 cells treated with sorafenib undergo a caspase-independent cell death that is inhibited by the RIPK1 inhibitor, necrostatin-1. Furthermore, treatment with sorafenib induces the interaction of RIPK1 with p62, as demonstrated by immunoprecipitation and a proximity ligation assay. Silencing of p62 decreases the RIPK1 protein levels and renders necrostatin-1 ineffective in blocking sorafenib-induced cell death. In summary, the formation of Atg5-deficient autophagosomes in response to sorafenib promotes the interaction of p62 with RIPK leading to cell death by necroptosis. PMID:26416459

  6. Stem cell death and survival in heart regeneration and repair.

    PubMed

    Abdelwahid, Eltyeb; Kalvelyte, Audrone; Stulpinas, Aurimas; de Carvalho, Katherine Athayde Teixeira; Guarita-Souza, Luiz Cesar; Foldes, Gabor

    2016-03-01

    Cardiovascular diseases are major causes of mortality and morbidity. Cardiomyocyte apoptosis disrupts cardiac function and leads to cardiac decompensation and terminal heart failure. Delineating the regulatory signaling pathways that orchestrate cell survival in the heart has significant therapeutic implications. Cardiac tissue has limited capacity to regenerate and repair. Stem cell therapy is a successful approach for repairing and regenerating ischemic cardiac tissue; however, transplanted cells display very high death percentage, a problem that affects success of tissue regeneration. Stem cells display multipotency or pluripotency and undergo self-renewal, however these events are negatively influenced by upregulation of cell death machinery that induces the significant decrease in survival and differentiation signals upon cardiovascular injury. While efforts to identify cell types and molecular pathways that promote cardiac tissue regeneration have been productive, studies that focus on blocking the extensive cell death after transplantation are limited. The control of cell death includes multiple networks rather than one crucial pathway, which underlies the challenge of identifying the interaction between various cellular and biochemical components. This review is aimed at exploiting the molecular mechanisms by which stem cells resist death signals to develop into mature and healthy cardiac cells. Specifically, we focus on a number of factors that control death and survival of stem cells upon transplantation and ultimately affect cardiac regeneration. We also discuss potential survival enhancing strategies and how they could be meaningful in the design of targeted therapies that improve cardiac function.

  7. Noncanonical cell death in the nematode Caenorhabditis elegans

    PubMed Central

    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. PMID:25065890

  8. [Death].

    PubMed

    Ribas, Jordi Domingo

    2003-12-01

    Intercultural factors are essential for reflection. In this article, the authors deals with a more direct vision on the special edition about Grief and Mourning, about the topic which lies in the depths of all of our consciences: death and the question what lies beyond death? The author provides us elements to reflect about concepts, some accepted in various cases, rejected in others, but always polemical, which help us to penetrate farther into the real mystery of life: death and what follows death.

  9. Neuronal cell death in neonatal hypoxia-ischemia.

    PubMed

    Northington, Frances J; Chavez-Valdez, Raul; Martin, Lee J

    2011-05-01

    Perinatal hypoxic-ischemic encephalopathy (HIE) is a significant cause of mortality and morbidity in infants and young children. Therapeutic opportunities are very limited for neonatal and pediatric HIE. Specific neural systems and populations of cells are selectively vulnerable in HIE; however, the mechanisms of degeneration are unresolved. These mechanisms involve oxidative stress, excitotoxicity, inflammation, and the activation of several different cell death pathways. Decades ago the structural and mechanistic basis of the cellular degeneration in HIE was thought to be necrosis. Subsequently, largely due to advances in cell biology and to experimental animal studies, emphasis has been switched to apoptosis or autophagy mediated by programmed cell death (PCD) mechanisms as important forms of degeneration in HIE. We have conceptualized based on morphological and biochemical data that this degeneration is better classified according to an apoptosis-necrosis cell death continuum and that programmed cell necrosis has prominent contribution in the neurodegeneration of HIE in animal models. It is likely that neonatal HIE evolves through many cell death chreodes influenced by the dynamic injury landscape. The relevant injury mechanisms remain to be determined in human neonatal HIE, though preliminary work suggests a complexity in the cell death mechanisms greater than that anticipated from experimental animal models. The accurate identification of the various cell death chreodes and their mechanisms unfolding within the immature brain matrix could provide fresh insight for developing meaningful therapies for neonatal and pediatric HIE. PMID:21520238

  10. Ferroptosis is Involved in Acetaminophen Induced Cell Death.

    PubMed

    Lőrincz, Tamás; Jemnitz, Katalin; Kardon, Tamás; Mandl, József; Szarka, András

    2015-09-01

    The recently described form of programmed cell death, ferroptosis can be induced by agents causing GSH depletion or the inhibition of GPX4. Ferroptosis clearly shows distinct morphologic, biochemical and genetic features from apoptosis, necrosis and autophagy. Since NAPQI the highly reactive metabolite of the widely applied analgesic and antipyretic, acetaminophen induces a cell death which can be characterized by GSH depletion, GPX inhibition and caspase independency the involvement of ferroptosis in acetaminophen induced cell death has been investigated. The specific ferroptosis inhibitor ferrostatin-1 failed to elevate the viability of acetaminophen treated HepG2 cells. It should be noticed that these cells do not form NAPQI due to the lack of phase I enzyme expression therefore GSH depletion cannot be observed. However in the case of acetaminophen treated primary mouse hepatocytes the significant elevation of cell viability could be observed upon ferrostatin-1 treatment. Similar to ferrostatin-1 treatment, the addition of the RIP1 kinase inhibitor necrostatin-1 could also elevate the viability of acetaminophen treated primary hepatocytes. Ferrostatin-1 has no influence on the expression of CYP2E1 or on the cellular GSH level which suggest that the protective effect of ferrostatin-1 in APAP induced cell death is not based on the reduced metabolism of APAP to NAPQI or on altered NAPQI conjugation by cellular GSH. Our results suggest that beyond necroptosis and apoptosis a third programmed cell death, ferroptosis is also involved in acetaminophen induced cell death in primary hepatocytes.

  11. Neuronal Cell Death in Neonatal Hypoxia-Ischemia

    PubMed Central

    Northington, Frances J.; Chavez-Valdez, Raul; Martin, Lee J.

    2014-01-01

    Perinatal hypoxic-ischemic encephalopathy (HIE) is a significant cause of mortality and morbidity in infants and young children. Therapeutic opportunities are very limited for neonatal and pediatric HIE. Specific neural systems and populations of cells are selectively vulnerable in HIE; however, the mechanisms of degeneration are unresolved. These mechanisms involve oxidative stress, excitotoxicity, inflammation, and the activation of several different cell death pathways. Decades ago the structural and mechanistic basis of the cellular degeneration in HIE was thought to be necrosis. Subsequently, largely due to advances in cell biology and to experimental animal studies, emphasis has been switched to apoptosis or autophagy mediated by programmed cell death (PCD) mechanisms as important forms of degeneration in HIE. We have conceptualized based on morphological and biochemical data that this degeneration is better classified according to an apoptosis-necrosis cell death continuum and that programmed cell necrosis has prominent contribution in the neurodegeneration of HIE in animal models. It is likely that neonatal HIE evolves through many cell death chreodes influenced by the dynamic injury landscape. The relevant injury mechanisms remain to be determined in human neonatal HIE, though preliminary work suggests a complexity in the cell death mechanisms greater than that anticipated from experimental animal models. The accurate identification of the various cell death chreodes and their mechanisms unfolding within the immature brain matrix could provide fresh insight for developing meaningful therapies for neonatal and pediatric HIE. PMID:21520238

  12. Ferroptosis is Involved in Acetaminophen Induced Cell Death.

    PubMed

    Lőrincz, Tamás; Jemnitz, Katalin; Kardon, Tamás; Mandl, József; Szarka, András

    2015-09-01

    The recently described form of programmed cell death, ferroptosis can be induced by agents causing GSH depletion or the inhibition of GPX4. Ferroptosis clearly shows distinct morphologic, biochemical and genetic features from apoptosis, necrosis and autophagy. Since NAPQI the highly reactive metabolite of the widely applied analgesic and antipyretic, acetaminophen induces a cell death which can be characterized by GSH depletion, GPX inhibition and caspase independency the involvement of ferroptosis in acetaminophen induced cell death has been investigated. The specific ferroptosis inhibitor ferrostatin-1 failed to elevate the viability of acetaminophen treated HepG2 cells. It should be noticed that these cells do not form NAPQI due to the lack of phase I enzyme expression therefore GSH depletion cannot be observed. However in the case of acetaminophen treated primary mouse hepatocytes the significant elevation of cell viability could be observed upon ferrostatin-1 treatment. Similar to ferrostatin-1 treatment, the addition of the RIP1 kinase inhibitor necrostatin-1 could also elevate the viability of acetaminophen treated primary hepatocytes. Ferrostatin-1 has no influence on the expression of CYP2E1 or on the cellular GSH level which suggest that the protective effect of ferrostatin-1 in APAP induced cell death is not based on the reduced metabolism of APAP to NAPQI or on altered NAPQI conjugation by cellular GSH. Our results suggest that beyond necroptosis and apoptosis a third programmed cell death, ferroptosis is also involved in acetaminophen induced cell death in primary hepatocytes. PMID:25962350

  13. Macrophage Activation Redirects Yersinia-Infected Host Cell Death from Apoptosis to Caspase-1-Dependent Pyroptosis

    PubMed Central

    Bergsbaken, Tessa; Cookson, Brad T

    2007-01-01

    Infection of macrophages by Yersinia species results in YopJ-dependent apoptosis, and naïve macrophages are highly susceptible to this form of cell death. Previous studies have demonstrated that macrophages activated with lipopolysaccharide (LPS) prior to infection are resistant to YopJ-dependent cell death; we found this simultaneously renders macrophages susceptible to killing by YopJ− Yersinia pseudotuberculosis (Yptb). YopJ− Yptb-induced macrophage death was dependent on caspase-1 activation, resulting in rapid permeability to small molecules, followed by membrane breakdown and DNA damage, and accompanied by cleavage and release of proinflammatory interleukin-18. Induction of caspase-1-dependent death, or pyroptosis, required the bacterial type III translocon but none of its known translocated proteins. Wild-type Yptb infection also triggered pyroptosis: YopJ-dependent activation of proapoptotic caspase-3 was significantly delayed in activated macrophages and resulted in caspase-1-dependent pyroptosis. The transition to susceptibility was not limited to LPS activation; it was also seen in macrophages activated with other Toll-like receptor (TLR) ligands and intact nonviable bacteria. Yptb infection triggered macrophage activation and activation of caspase-1 in vivo. Y. pestis infection of activated macrophages also stimulated caspase-1 activation. These results indicate that host signaling triggered by TLR and other activating ligands during the course of Yersinia infection redirects both the mechanism of host cell death and the downstream consequences of death by shifting from noninflammatory apoptosis to inflammatory pyroptosis. PMID:17983266

  14. Role of mitochondria in apoptotic and necroptotic cell death in the developing brain

    PubMed Central

    Thornton, Claire; Hagberg, Henrik

    2015-01-01

    Hypoxic–ischemic encephalopathy induces secondary brain injury characterized by delayed energy failure. Currently, therapeutic hypothermia is the sole treatment available after severe intrapartum asphyxia in babies and acts to attenuate secondary loss of high energy phosphates improving both short- and long-term outcome. In order to develop the next generation of neuroprotective therapies, we urgently need to understand the underlying molecular mechanisms leading to cell death. Hypoxia–ischemia creates a toxic intracellular environment including accumulation of reactive oxygen/nitrosative species and intracellular calcium after the insult, inducing mitochondrial impairment. More specifically mitochondrial respiration is suppressed and calcium signaling is dysregulated. At a certain threshold, Bax-dependent mitochondrial permeabilization will occur leading to activation of caspase-dependent and apoptosis-inducing factor-dependent apoptotic cell death. In addition, hypoxia–ischemia induces inflammation, which leads to the release of TNF-α, TRAIL, TWEAK, FasL and Toll-like receptor agonists that will activate death receptors on neurons and oligodendroglia. Death receptors trigger apoptotic death via caspase-8 and necroptotic cell death through formation of the necrosome (composed of RIP1, RIP3 and MLKL), both of which converge at the mitochondria. PMID:25661091

  15. Sickle cell trait and sudden death--bringing it home.

    PubMed Central

    Mitchell, Bruce L.

    2007-01-01

    Sickle cell trait continues to be the leading cause of sudden death for young African Americans in military basic training and civilian organized sports. The syndrome may have caused the death of up to 10 college football players since 1974 and, as recently as 2000, was suspected as the cause of death of three U.S. Army recruits. The penal military-style boot camps in the United States and the recent death of two teenagers with sickle cell trait merits renewed vigor in the education of athletic instructors, the military and the public about conditions associated with sudden death in individuals with sickle cell trait. Images Figure 1 Figure 2 PMID:17393956

  16. Radiation-induced Cochlea hair cell death: mechanisms and protection.

    PubMed

    Tan, Pei-Xin; Du, Sha-Sha; Ren, Chen; Yao, Qi-Wei; Yuan, Ya-Wei

    2013-01-01

    Cochlea hair cell death is regarded to be responsible for the radiation-induced sensorineural hearing loss (SNHL), which is one of the principal complications of radiotherapy (RT) for head and neck cancers. In this mini- review, we focus on the current progresses trying to unravel mechanisms of radiation-induced hair cell death and find out possible protection. P53, reactive oxygen species (ROS) and c-Jun N-terminal kinase (JNK) pathways have been proposed as pivotal in the processes leading to radiation hair cell death. Potential protectants, such as amifostine, N-acetylcysteine (NAC) and epicatechin (EC) , are claimed to be effective at reducing radiation- inducedhair cell death. The RT dosage, selection and application of concurrent chemotherapy should be pre- examined in order to minimize the damage to cochlea hair cells.

  17. Amplitude death and synchronized states in nonlinear time-delay systems coupled through mean-field diffusion.

    PubMed

    Banerjee, Tanmoy; Biswas, Debabrata

    2013-12-01

    We explore and experimentally demonstrate the phenomena of amplitude death (AD) and the corresponding transitions through synchronized states that lead to AD in coupled intrinsic time-delayed hyperchaotic oscillators interacting through mean-field diffusion. We identify a novel synchronization transition scenario leading to AD, namely transitions among AD, generalized anticipatory synchronization (GAS), complete synchronization (CS), and generalized lag synchronization (GLS). This transition is mediated by variation of the difference of intrinsic time-delays associated with the individual systems and has no analogue in non-delayed systems or coupled oscillators with coupling time-delay. We further show that, for equal intrinsic time-delays, increasing coupling strength results in a transition from the unsynchronized state to AD state via in-phase (complete) synchronized states. Using Krasovskii-Lyapunov theory, we derive the stability conditions that predict the parametric region of occurrence of GAS, GLS, and CS; also, using a linear stability analysis, we derive the condition of occurrence of AD. We use the error function of proper synchronization manifold and a modified form of the similarity function to provide the quantitative support to GLS and GAS. We demonstrate all the scenarios in an electronic circuit experiment; the experimental time-series, phase-plane plots, and generalized autocorrelation function computed from the experimental time series data are used to confirm the occurrence of all the phenomena in the coupled oscillators.

  18. Amplitude death and synchronized states in nonlinear time-delay systems coupled through mean-field diffusion

    NASA Astrophysics Data System (ADS)

    Banerjee, Tanmoy; Biswas, Debabrata

    2013-12-01

    We explore and experimentally demonstrate the phenomena of amplitude death (AD) and the corresponding transitions through synchronized states that lead to AD in coupled intrinsic time-delayed hyperchaotic oscillators interacting through mean-field diffusion. We identify a novel synchronization transition scenario leading to AD, namely transitions among AD, generalized anticipatory synchronization (GAS), complete synchronization (CS), and generalized lag synchronization (GLS). This transition is mediated by variation of the difference of intrinsic time-delays associated with the individual systems and has no analogue in non-delayed systems or coupled oscillators with coupling time-delay. We further show that, for equal intrinsic time-delays, increasing coupling strength results in a transition from the unsynchronized state to AD state via in-phase (complete) synchronized states. Using Krasovskii-Lyapunov theory, we derive the stability conditions that predict the parametric region of occurrence of GAS, GLS, and CS; also, using a linear stability analysis, we derive the condition of occurrence of AD. We use the error function of proper synchronization manifold and a modified form of the similarity function to provide the quantitative support to GLS and GAS. We demonstrate all the scenarios in an electronic circuit experiment; the experimental time-series, phase-plane plots, and generalized autocorrelation function computed from the experimental time series data are used to confirm the occurrence of all the phenomena in the coupled oscillators.

  19. Octylphenol induces vitellogenin production and cell death in fish hepatocytes

    SciTech Connect

    Toomey, B.H.; Monteverdi, G.H.; Di Giulio, R.T.

    1999-04-01

    The effects of octylphenol (OP) on vitellogenin production and cell death in hepatocytes from brown bullhead catfish (Americurus nebulosus) were studied. Production of vitellogenin was induced in hepatocytes exposed to 10 to 50 {micro}M OP, whereas a higher concentration of OP (100 {micro}M) induced apoptotic cell death. By 3 h after the addition of 100 {micro}M OP, dying cells showed chromatin condensation and DNA fragmentation as determined by fluorescence microscopy and gel electrophoresis. Later stages of cell death (nuclear membrane breakdown and cell fragmentation into apoptotic bodies) were identified in cells exposed to OP for at least 6 h. Hepatocytes exposed to 100 {micro}M OP also produced less vitellogenin than cells exposed to 50 {micro}M OP. An estrogen receptor antagonist, tamoxifen, greatly decreased vitellogenin production in OP-exposed hepatocytes from male fish but did not decrease cell death in these cells. Thus, although the ability of OP to induce vitellogenin production is likely mediated through interactions with the estrogen receptor, the induction of apoptotic cell death by OP does not appear to be dependent on its estrogenic activity but may be a more general toxic effect.

  20. Cell biology: Death drags down the neighbourhood

    NASA Astrophysics Data System (ADS)

    Vasquez, Claudia G.; Martin, Adam C.

    2015-02-01

    An analysis of dying cells reveals that they play an active part in modifying tissue shape by pulling on neighbouring cells. This induces neighbouring cells to contract at their apices, which results in tissue folding. See Letter p.245

  1. The Impact of Autophagy on Cell Death Modalities

    PubMed Central

    Ryter, Stefan W.; Choi, Augustine M. K.

    2014-01-01

    Autophagy represents a homeostatic cellular mechanism for the turnover of organelles and proteins, through a lysosome-dependent degradation pathway. During starvation, autophagy facilitates cell survival through the recycling of metabolic precursors. Additionally, autophagy can modulate other vital processes such as programmed cell death (e.g., apoptosis), inflammation, and adaptive immune mechanisms and thereby influence disease pathogenesis. Selective pathways can target distinct cargoes (e.g., mitochondria and proteins) for autophagic degradation. At present, the causal relationship between autophagy and various forms of regulated or nonregulated cell death remains unclear. Autophagy can occur in association with necrosis-like cell death triggered by caspase inhibition. Autophagy and apoptosis have been shown to be coincident or antagonistic, depending on experimental context, and share cross-talk between signal transduction elements. Autophagy may modulate the outcome of other regulated forms of cell death such as necroptosis. Recent advances suggest that autophagy can dampen inflammatory responses, including inflammasome-dependent caspase-1 activation and maturation of proinflammatory cytokines. Autophagy may also act as regulator of caspase-1 dependent cell death (pyroptosis). Strategies aimed at modulating autophagy may lead to therapeutic interventions for diseases in which apoptosis or other forms of regulated cell death may play a cardinal role. PMID:24639873

  2. Heme oxygenase-1 accelerates erastin-induced ferroptotic cell death

    PubMed Central

    Kwon, Min-Young; Park, Eunhee

    2015-01-01

    The oncogenic RAS-selective lethal small molecule Erastin triggers a unique iron-dependent form of nonapoptotic cell death termed ferroptosis. Ferroptosis is dependent upon the production of intracellular iron-dependent reactive oxygen species (ROS), but not other metals. However, key regulators remain unknown. The heme oxygenase (HO) is a major intracellular source of iron. In this study, the role of heme oxygenase in Erastin-triggered ferroptotic cancer cell death has been investigated. Zinc protoporphyrin IX (ZnPP), a HO-1 inhibitor, prevented Erastin-triggered ferroptotic cancer cell death. Furthermore, Erastin induced the protein and mRNA levels of HO-1 in HT-1080 fibrosarcoma cells. HO-1+/+ and HO-1−/− fibroblast, HO-1 overexpression, and chycloheximide-treated experiments revealed that the expression of HO-1 has a decisive effects in Erastin-triggered cell death. Hemin and CO-releasing molecules (CORM) promote Erastin-induced ferroptotic cell death, not by biliverdin and bilirubin. In addition, hemin and CORM accelerate the HO-1 expression in the presence of Erastin and increase membranous lipid peroxidation. Thus, HO-1 is an essential enzyme for iron-dependent lipid peroxidation during ferroptotic cell death. PMID:26405158

  3. Inhibition of regulated cell death by cell-penetrating peptides.

    PubMed

    Krautwald, Stefan; Dewitz, Christin; Fändrich, Fred; Kunzendorf, Ulrich

    2016-06-01

    Development of the means to efficiently and continuously renew missing and non-functional proteins in diseased cells remains a major goal in modern molecular medicine. While gene therapy has the potential to achieve this, substantial obstacles must be overcome before clinical application can be considered. A promising alternative approach is the direct delivery of non-permeant active biomolecules, such as oligonucleotides, peptides and proteins, to the affected cells with the purpose of ameliorating an advanced disease process. In addition to receptor-mediated endocytosis, cell-penetrating peptides are widely used as vectors for rapid translocation of conjugated molecules across cell membranes into intracellular compartments and the delivery of these therapeutic molecules is generally referred to as novel prospective protein therapy. As a broad coverage of the enormous amount of published data in this field is unrewarding, this review will provide a brief, focused overview of the technology and a summary of recent studies of the most commonly used protein transduction domains and their potential as therapeutic agents for the treatment of cellular damage and the prevention of regulated cell death. PMID:27048815

  4. Acetylsalicylic acid induces programmed cell death in Arabidopsis cell cultures.

    PubMed

    García-Heredia, José M; Hervás, Manuel; De la Rosa, Miguel A; Navarro, José A

    2008-06-01

    Acetylsalicylic acid (ASA), a derivative from the plant hormone salicylic acid (SA), is a commonly used drug that has a dual role in animal organisms as an anti-inflammatory and anticancer agent. It acts as an inhibitor of cyclooxygenases (COXs), which catalyze prostaglandins production. It is known that ASA serves as an apoptotic agent on cancer cells through the inhibition of the COX-2 enzyme. Here, we provide evidences that ASA also behaves as an agent inducing programmed cell death (PCD) in cell cultures of the model plant Arabidopsis thaliana, in a similar way than the well-established PCD-inducing agent H(2)O(2), although the induction of PCD by ASA requires much lower inducer concentrations. Moreover, ASA is herein shown to be a more efficient PCD-inducing agent than salicylic acid. ASA treatment of Arabidopsis cells induces typical PCD-linked morphological and biochemical changes, namely cell shrinkage, nuclear DNA degradation, loss of mitochondrial membrane potential, cytochrome c release from mitochondria and induction of caspase-like activity. However, the ASA effect can be partially reverted by jasmonic acid. Taking together, these results reveal the existence of common features in ASA-induced animal apoptosis and plant PCD, and also suggest that there are similarities between the pathways of synthesis and function of prostanoid-like lipid mediators in animal and plant organisms.

  5. A unifying mechanism for cancer cell death through ion channel activation by HAMLET.

    PubMed

    Storm, Petter; Klausen, Thomas Kjaer; Trulsson, Maria; Ho C S, James; Dosnon, Marion; Westergren, Tomas; Chao, Yinxia; Rydström, Anna; Yang, Henry; Pedersen, Stine Falsig; Svanborg, Catharina

    2013-01-01

    Ion channels and ion fluxes control many aspects of tissue homeostasis. During oncogenic transformation, critical ion channel functions may be perturbed but conserved tumor specific ion fluxes remain to be defined. Here we used the tumoricidal protein-lipid complex HAMLET as a probe to identify ion fluxes involved in tumor cell death. We show that HAMLET activates a non-selective cation current, which reached a magnitude of 2.74±0.88 nA within 1.43±0.13 min from HAMLET application. Rapid ion fluxes were essential for HAMLET-induced carcinoma cell death as inhibitors (amiloride, BaCl2), preventing the changes in free cellular Na(+) and K(+) concentrations also prevented essential steps accompanying carcinoma cell death, including changes in morphology, uptake, global transcription, and MAP kinase activation. Through global transcriptional analysis and phosphorylation arrays, a strong ion flux dependent p38 MAPK response was detected and inhibition of p38 signaling delayed HAMLET-induced death. Healthy, differentiated cells were resistant to HAMLET challenge, which was accompanied by innate immunity rather than p38-activation. The results suggest, for the first time, a unifying mechanism for the initiation of HAMLET's broad and rapid lethal effect on tumor cells. These findings are particularly significant in view of HAMLET's documented therapeutic efficacy in human studies and animal models. The results also suggest that HAMLET offers a two-tiered therapeutic approach, killing cancer cells while stimulating an innate immune response in surrounding healthy tissues.

  6. Targeting Cell Death Pathways for Therapeutic Intervention in Kidney Diseases.

    PubMed

    Garg, Jay P; Vucic, Domagoj

    2016-05-01

    Precise regulation of cell death and survival is essential for proper maintenance of organismal homeostasis, development, and the immune system. Deregulated cell death can lead to developmental defects, neuropathies, infections, and cancer. Kidney diseases, especially acute pathologies linked to ischemia-reperfusion injury, are among illnesses that profoundly are affected by improper regulation or execution of cell death pathways. Attempts to develop medicines for kidney diseases have been impacted by the complexity of these pathologies given the heterogeneous patient population and diverse etiologies. By analyzing cell death pathways activated in kidney diseases, we attempt to differentiate their importance for these pathologies with a goal of identifying those that have more profound impact and the best therapeutic potential. Although classic apoptosis still might be important, regulated necrosis pathways including necroptosis, ferroptosis, parthanatos, and mitochondrial permeability transition-associated cell death play a significantly role in kidney diseases, especially in acute kidney pathologies. Although targeting receptor-interacting protein 1 kinase appears to be the best therapeutic strategy, combination with inhibitors of other cell death pathways is likely to bring superior benefit and possible cure to patients suffering from kidney diseases. PMID:27339381

  7. Prodigiosin inhibits motility and activates bacterial cell death revealing molecular biomarkers of programmed cell death.

    PubMed

    Darshan, N; Manonmani, H K

    2016-12-01

    The antimicrobial activity of prodigiosin from Serratia nematodiphila darsh1, a bacterial pigment was tested against few food borne bacterial pathogens Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The mode of action of prodigiosin was studied. Prodigiosin induced bactericidal activity indicating a stereotypical set of biochemical and morphological feature of Programmed cell death (PCD). PCD involves DNA fragmentation, generation of ROS, and expression of a protein with caspase-like substrate specificity in bacterial cells. Prodigiosin was observed to be internalized into bacterial cells and was localized predominantly in the membrane and the nuclear fraction, thus, facilitating intracellular trafficking and then binding of prodigiosin to the bacterial DNA. Corresponding to an increasing concentration of prodigiosin, the level of certain proteases were observed to increase in bacteria studied, thus initiating the onset of PCD. Prodigiosin at a sub-inhibitory concentration inhibits motility of pathogens. Our observations indicated that prodigiosin could be a promising antibacterial agent and could be used in the prevention of bacterial infections. PMID:27460563

  8. Prodigiosin inhibits motility and activates bacterial cell death revealing molecular biomarkers of programmed cell death.

    PubMed

    Darshan, N; Manonmani, H K

    2016-12-01

    The antimicrobial activity of prodigiosin from Serratia nematodiphila darsh1, a bacterial pigment was tested against few food borne bacterial pathogens Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The mode of action of prodigiosin was studied. Prodigiosin induced bactericidal activity indicating a stereotypical set of biochemical and morphological feature of Programmed cell death (PCD). PCD involves DNA fragmentation, generation of ROS, and expression of a protein with caspase-like substrate specificity in bacterial cells. Prodigiosin was observed to be internalized into bacterial cells and was localized predominantly in the membrane and the nuclear fraction, thus, facilitating intracellular trafficking and then binding of prodigiosin to the bacterial DNA. Corresponding to an increasing concentration of prodigiosin, the level of certain proteases were observed to increase in bacteria studied, thus initiating the onset of PCD. Prodigiosin at a sub-inhibitory concentration inhibits motility of pathogens. Our observations indicated that prodigiosin could be a promising antibacterial agent and could be used in the prevention of bacterial infections.

  9. Cell death during crisis is mediated by mitotic telomere deprotection.

    PubMed

    Hayashi, Makoto T; Cesare, Anthony J; Rivera, Teresa; Karlseder, Jan

    2015-06-25

    Tumour formation is blocked by two barriers: replicative senescence and crisis. Senescence is triggered by short telomeres and is bypassed by disruption of tumour-suppressive pathways. After senescence bypass, cells undergo crisis, during which almost all of the cells in the population die. Cells that escape crisis harbour unstable genomes and other parameters of transformation. The mechanism of cell death during crisis remains unexplained. Here we show that human cells in crisis undergo spontaneous mitotic arrest, resulting in death during mitosis or in the following cell cycle. This phenotype is induced by loss of p53 function, and is suppressed by telomerase overexpression. Telomere fusions triggered mitotic arrest in p53-compromised non-crisis cells, indicating that such fusions are the underlying cause of cell death. Exacerbation of mitotic telomere deprotection by partial TRF2 (also known as TERF2) knockdown increased the ratio of cells that died during mitotic arrest and sensitized cancer cells to mitotic poisons. We propose a crisis pathway wherein chromosome fusions induce mitotic arrest, resulting in mitotic telomere deprotection and cell death, thereby eliminating precancerous cells from the population.

  10. Surviving apoptosis: life-death signaling in single cells

    PubMed Central

    Flusberg, Deborah A.; Sorger, Peter K.

    2015-01-01

    Tissue development and homeostasis are regulated by opposing pro-survival and pro-death signals. An interesting feature of the Tumor Necrosis Factor (TNF) family of ligands is that they simultaneously activate opposing signals within a single cell via the same ligand-receptor complex. The magnitude of pro-death events such as caspase activation and pro-survival events such as NF-κB activation vary not only from one cell type to the next but also among individual cells of the same type due to intrinsic and extrinsic noise. The molecules involved in these pro-survival/pro-death pathways, and the different phenotypes that result from their activities, have been recently reviewed. Here we focus on the impact of cell-to-cell variability in the strength of these opposing signals on shaping cell fate decisions. PMID:25920803

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

    PubMed

    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. PMID:23915134

  12. Understanding Cone Photoreceptor Cell Death in Achromatopsia.

    PubMed

    Carvalho, Livia S; Vandenberghe, Luk H

    2016-01-01

    Colour vision is only achieved in the presence of healthy and functional cone photoreceptors found in the retina. It is an essential component of human vision and usually the first complaint patients undergoing vision degeneration have is the loss of daylight colour vision. Therefore, an understanding of the biology and basic mechanisms behind cone death under the degenerative state of retinal dystrophies and how the activation of the apoptotic pathway is triggered will provide valuable knowledge. It will also have broader applications for a spectrum of visual disorders and will be critical for future advances in translational research. PMID:26427416

  13. Targeting Cell Survival Proteins for Cancer Cell Death

    PubMed Central

    Pandey, Manoj K.; Prasad, Sahdeo; Tyagi, Amit Kumar; Deb, Lokesh; Huang, Jiamin; Karelia, Deepkamal N.; Amin, Shantu G.; Aggarwal, Bharat B.

    2016-01-01

    Escaping from cell death is one of the adaptations that enable cancer cells to stave off anticancer therapies. The key players in avoiding apoptosis are collectively known as survival proteins. Survival proteins comprise the Bcl-2, inhibitor of apoptosis (IAP), and heat shock protein (HSP) families. The aberrant expression of these proteins is associated with a range of biological activities that promote cancer cell survival, proliferation, and resistance to therapy. Several therapeutic strategies that target survival proteins are based on mimicking BH3 domains or the IAP-binding motif or competing with ATP for the Hsp90 ATP-binding pocket. Alternative strategies, including use of nutraceuticals, transcriptional repression, and antisense oligonucleotides, provide options to target survival proteins. This review focuses on the role of survival proteins in chemoresistance and current therapeutic strategies in preclinical or clinical trials that target survival protein signaling pathways. Recent approaches to target survival proteins-including nutraceuticals, small-molecule inhibitors, peptides, and Bcl-2-specific mimetic are explored. Therapeutic inventions targeting survival proteins are promising strategies to inhibit cancer cell survival and chemoresistance. However, complete eradication of resistance is a distant dream. For a successful clinical outcome, pretreatment with novel survival protein inhibitors alone or in combination with conventional therapies holds great promise. PMID:26927133

  14. Measuring Cell Death by Propidium Iodide Uptake and Flow Cytometry.

    PubMed

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

    2016-01-01

    Propidium iodide (PI) is a small fluorescent molecule that binds to DNA but cannot passively traverse into cells that possess an intact plasma membrane. PI uptake versus exclusion can be used to discriminate dead cells, in which plasma membranes become permeable regardless of the mechanism of death, from live cells with intact membranes. PI is excited by wavelengths between 400 and 600 nm and emits light between 600 and 700 nm, and is therefore compatible with lasers and photodetectors commonly available in flow cytometers. This protocol for PI staining can be used to quantitate cell death in most modern research facilities and universities. PMID:27371595

  15. Morphological and cytochemical determination of cell death by apoptosis

    PubMed Central

    Sobel, Burton E.; Budd, Ralph C.

    2007-01-01

    Several modes of cell death are now recognized, including necrosis, apoptosis, and autophagy. Oftentimes the distinctions between these various modes may not be apparent, although the precise mode may be physiologically important. Accordingly, it is often desirable to be able to classify the mode of cell death. Apoptosis was originally defined by structural alterations in cells observable by transmitted light and electron microscopy. Today, a wide variety of imaging and cytochemical techniques are available for the investigation of apoptosis. This review will highlight many of these methods, and provide a critique on the advantages and disadvantages associated with them for the specific identification of apoptotic cells in culture and tissues. PMID:18000678

  16. Transcriptomics and functional genomics of ROS-induced cell death regulation by RADICAL-INDUCED CELL DEATH1.

    PubMed

    Brosché, Mikael; Blomster, Tiina; Salojärvi, Jarkko; Cui, Fuqiang; Sipari, Nina; Leppälä, Johanna; Lamminmäki, Airi; Tomai, Gloria; Narayanasamy, Shaman; Reddy, Ramesha A; Keinänen, Markku; Overmyer, Kirk; Kangasjärvi, Jaakko

    2014-02-01

    Plant responses to changes in environmental conditions are mediated by a network of signaling events leading to downstream responses, including changes in gene expression and activation of cell death programs. Arabidopsis thaliana RADICAL-INDUCED CELL DEATH1 (RCD1) has been proposed to regulate plant stress responses by protein-protein interactions with transcription factors. Furthermore, the rcd1 mutant has defective control of cell death in response to apoplastic reactive oxygen species (ROS). Combining transcriptomic and functional genomics approaches we first used microarray analysis in a time series to study changes in gene expression after apoplastic ROS treatment in rcd1. To identify a core set of cell death regulated genes, RCD1-regulated genes were clustered together with other array experiments from plants undergoing cell death or treated with various pathogens, plant hormones or other chemicals. Subsequently, selected rcd1 double mutants were constructed to further define the genetic requirements for the execution of apoplastic ROS induced cell death. Through the genetic analysis we identified WRKY70 and SGT1b as cell death regulators functioning downstream of RCD1 and show that quantitative rather than qualitative differences in gene expression related to cell death appeared to better explain the outcome. Allocation of plant energy to defenses diverts resources from growth. Recently, a plant response termed stress-induced morphogenic response (SIMR) was proposed to regulate the balance between defense and growth. Using a rcd1 double mutant collection we show that SIMR is mostly independent of the classical plant defense signaling pathways and that the redox balance is involved in development of SIMR. PMID:24550736

  17. Transcriptomics and Functional Genomics of ROS-Induced Cell Death Regulation by RADICAL-INDUCED CELL DEATH1

    PubMed Central

    Salojärvi, Jarkko; Cui, Fuqiang; Sipari, Nina; Leppälä, Johanna; Lamminmäki, Airi; Tomai, Gloria; Narayanasamy, Shaman; Reddy, Ramesha A.; Keinänen, Markku; Overmyer, Kirk; Kangasjärvi, Jaakko

    2014-01-01

    Plant responses to changes in environmental conditions are mediated by a network of signaling events leading to downstream responses, including changes in gene expression and activation of cell death programs. Arabidopsis thaliana RADICAL-INDUCED CELL DEATH1 (RCD1) has been proposed to regulate plant stress responses by protein-protein interactions with transcription factors. Furthermore, the rcd1 mutant has defective control of cell death in response to apoplastic reactive oxygen species (ROS). Combining transcriptomic and functional genomics approaches we first used microarray analysis in a time series to study changes in gene expression after apoplastic ROS treatment in rcd1. To identify a core set of cell death regulated genes, RCD1-regulated genes were clustered together with other array experiments from plants undergoing cell death or treated with various pathogens, plant hormones or other chemicals. Subsequently, selected rcd1 double mutants were constructed to further define the genetic requirements for the execution of apoplastic ROS induced cell death. Through the genetic analysis we identified WRKY70 and SGT1b as cell death regulators functioning downstream of RCD1 and show that quantitative rather than qualitative differences in gene expression related to cell death appeared to better explain the outcome. Allocation of plant energy to defenses diverts resources from growth. Recently, a plant response termed stress-induced morphogenic response (SIMR) was proposed to regulate the balance between defense and growth. Using a rcd1 double mutant collection we show that SIMR is mostly independent of the classical plant defense signaling pathways and that the redox balance is involved in development of SIMR. PMID:24550736

  18. The response of normal and ataxia-telangiectasia cells to bleomycin: relationships between chromosome damage, cell cycle delay and cell killing.

    PubMed

    Zampetti-Bosseler, F; Scott, D

    1985-08-01

    In agreement with our earlier observation (Scott and Zampetti-Bosseler, 1982) on X-irradiated normal and ataxia-telangiectasia (A-T) fibroblasts, we now report that after bleomycin or neocarzinostatin treatment also, A-T cells exhibit less G2 delay than normal cells. We confirm that A-T cells sustain more chromosome damage and lethality than normal cells after bleomycin. These observations support the hypothesis (Painter and Young, 1980) that A-T cells are defective in the recognition of certain lesions which normally lead to delays in progression through the cell cycle, during which they are repaired, and which, if unrepaired, lead to cell-lethal chromosome damage. However, we find that after bleomycin, as opposed to X-rays, the contribution of this type of lesion to cell death is minimal. The predominant lesions leading to cell death after bleomycin are not manifested at chromosome aberrations and do not lead to G2 delay or DNA-synthesis inhibition. A-T cells are defective in the recognition and/or repair of both types of lesion.

  19. A matter of life and cell death.

    PubMed

    Evan, G; Littlewood, T

    1998-08-28

    In multicellular organisms, mutations in somatic cells affecting critical genes that regulate cell proliferation and survival cause fatal cancers. Repair of the damage is one obvious option, although the relative inconsequence of individual cells in metazoans means that it is often a "safer" strategy to ablate the offending cell. Not surprisingly, corruption of the machinery that senses or implements DNA damage greatly predisposes to cancer. Nonetheless, even when oncogenic mutations do occur, there exist potent mechanisms that limit the expansion of affected cells by suppressing their proliferation or triggering their suicide. Growing understanding of these innate mechanisms is suggesting novel therapeutic strategies for cancer.

  20. Acetaminophen Induces Human Neuroblastoma Cell Death through NFKB Activation

    PubMed Central

    Posadas, Inmaculada; Santos, Pablo; Ceña, Valentín

    2012-01-01

    Neuroblastoma resistance to apoptosis may contribute to the aggressive behavior of this tumor. Therefore, it would be relevant to activate endogenous cellular death mechanisms as a way to improve neuroblastoma therapy. We used the neuroblastoma SH-SY5Y cell line as a model to study the mechanisms involved in acetaminophen (AAP)-mediated toxicity by measuring CYP2E1 enzymatic activity, NFkB p65 subunit activation and translocation to the nucleus, Bax accumulation into the mitochondria, cytochrome c release and caspase activation. AAP activates the intrinsic death pathway in the SH-SY5Y human neuroblastoma cell line. AAP metabolism is partially responsible for this activation, because blockade of the cytochrome CYP2E1 significantly reduced but did not totally prevent, AAP-induced SH-SY5Y cell death. AAP also induced NFkB p65 activation by phosphorylation and its translocation to the nucleus, where NFkB p65 increased IL-1β production. This increase contributed to neuroblastoma cell death through a mechanism involving Bax accumulation into the mitochondria, cytochrome c release and caspase3 activation. Blockade of NFkB translocation to the nucleus by the peptide SN50 prevented AAP-mediated cell death and IL-1β production. Moreover, overexpression of the antiapoptotic protein Bcl-xL did not decrease AAP-mediated IL-1β production, but prevented both AAP and IL-1β-mediated cell death. We also confirmed the AAP toxic actions on SK-N-MC neuroepithelioma and U87MG glioblastoma cell lines. The results presented here suggest that AAP activates the intrinsic death pathway in neuroblastoma cells through a mechanism involving NFkB and IL-1β. PMID:23166834

  1. BGP-15 inhibits caspase-independent programmed cell death in acetaminophen-induced liver injury

    SciTech Connect

    Nagy, Gabor; Szarka, Andras; Lotz, Gabor; Doczi, Judit; Wunderlich, Livius; Kiss, Andras; Jemnitz, Katalin; Veres, Zsuzsa; Banhegyi, Gabor; Schaff, Zsuzsa; Suemegi, Balazs; Mandl, Jozsef

    2010-02-15

    It has been recently shown that acute acetaminophen toxicity results in endoplasmic reticulum redox stress and an increase in cells with apoptotic phenotype in liver. Since activation of effector caspases was absent, the relevance of caspase-independent mechanisms in acetaminophen-induced programmed cell death was investigated. BGP-15, a drug with known protective actions in conditions involving redox imbalance, has been co-administered with a single sublethal dose of acetaminophen. Proapoptotic events and outcome of the injury were investigated. ER redox alterations and early ER-stress-related signaling events induced by acetaminophen, such as ER glutathione depletion, phosphorylation of eIF2alpha and JNK and induction of the transcription factor GADD153, were not counteracted by co-treatment with BGP-15. However, BGP-15 prevented AIF mitochondria-to-nucleus translocation and mitochondrial depolarization. BGP-15 co-treatment attenuated the rate of acetaminophen-induced cell death as assessed by apoptotic index and enzyme serum release. These results reaffirm that acute acetaminophen toxicity involves oxidative stress-induced caspase-independent cell death. In addition, pharmacological inhibition of AIF translocation may effectively protect against or at least delay acetaminophen-induced programmed cell death.

  2. BGP-15 inhibits caspase-independent programmed cell death in acetaminophen-induced liver injury.

    PubMed

    Nagy, Gábor; Szarka, András; Lotz, Gábor; Dóczi, Judit; Wunderlich, Lívius; Kiss, András; Jemnitz, Katalin; Veres, Zsuzsa; Bánhegyi, Gábor; Schaff, Zsuzsa; Sümegi, Balázs; Mandl, József

    2010-02-15

    It has been recently shown that acute acetaminophen toxicity results in endoplasmic reticulum redox stress and an increase in cells with apoptotic phenotype in liver. Since activation of effector caspases was absent, the relevance of caspase-independent mechanisms in acetaminophen-induced programmed cell death was investigated. BGP-15, a drug with known protective actions in conditions involving redox imbalance, has been co-administered with a single sublethal dose of acetaminophen. Proapoptotic events and outcome of the injury were investigated. ER redox alterations and early ER-stress-related signaling events induced by acetaminophen, such as ER glutathione depletion, phosphorylation of eIF2alpha and JNK and induction of the transcription factor GADD153, were not counteracted by co-treatment with BGP-15. However, BGP-15 prevented AIF mitochondria-to-nucleus translocation and mitochondrial depolarization. BGP-15 co-treatment attenuated the rate of acetaminophen-induced cell death as assessed by apoptotic index and enzyme serum release. These results reaffirm that acute acetaminophen toxicity involves oxidative stress-induced caspase-independent cell death. In addition, pharmacological inhibition of AIF translocation may effectively protect against or at least delay acetaminophen-induced programmed cell death.

  3. External and internal triggers of cell death in yeast.

    PubMed

    Falcone, Claudio; Mazzoni, Cristina

    2016-06-01

    In recent years, yeast was confirmed as a useful eukaryotic model system to decipher the complex mechanisms and networks occurring in higher eukaryotes, particularly in mammalian cells, in physiological as well in pathological conditions. This article focuses attention on the contribution of yeast in the study of a very complex scenario, because of the number and interconnection of pathways, represented by cell death. Yeast, although it is a unicellular organism, possesses the basal machinery of different kinds of cell death occurring in higher eukaryotes, i.e., apoptosis, regulated necrosis and autophagy. Here we report the current knowledge concerning the yeast orthologs of main mammalian cell death regulators and executors, the role of organelles and compartments, and the cellular phenotypes observed in the different forms of cell death in response to external and internal triggers. Thanks to the ease of genetic manipulation of this microorganism, yeast strains expressing human genes that promote or counteract cell death, onset of tumors and neurodegenerative diseases have been constructed. The effects on yeast cells of some of these genes are also presented.

  4. Smac-mimetic-induced epithelial cell death reduces the growth of renal cysts.

    PubMed

    Fan, Lucy X; Zhou, Xia; Sweeney, William E; Wallace, Darren P; Avner, Ellis D; Grantham, Jared J; Li, Xiaogang

    2013-12-01

    Past efforts to pharmacologically disrupt the development and growth of renal cystic lesions focused primarily on normalizing the activity of a specific signaling molecule, but the effects of stimulating apoptosis in the proliferating epithelial cells have not been well studied. Although benign, ADPKD renal cysts created by the sustained proliferation of epithelial cells resemble tumors, and malignant cell death can be achieved by cotreatment with TNF-α and a mimetic of second mitochondria-derived activator of caspase (Smac). Notably, TNF-α accumulates to high levels in ADPKD cyst fluid. Here, we report that an Smac-mimetic selectively induces TNF-α-dependent cystic renal epithelial cell death, leading to the removal of cystic epithelial cells from renal tissues and delaying cyst formation. In vitro, a Smac-mimetic (GT13072) induced the degradation of cIAP1 that is required but not sufficient for cell death. Cotreatment with TNF-α augmented the formation and activation of the RIPK1-dependent death complex and the degradation and cleavage of FLIP, an inhibitor of caspase-8, in renal cystic epithelial cells. This approach produced death specifically in Pkd1 mutant epithelial cells, with no effect on normal renal epithelial cells. Moreover, treatment with the Smac-mimetic slowed cyst and kidney enlargement and preserved renal function in two genetic strains of mice with Pkd1 mutations. Thus, our mechanistic data characterize an apoptotic pathway, activated by the selective synergy of an Smac-mimetic and TNF-α in renal cyst fluid, that attenuates cyst development, providing an innovative translational platform for the rational development of novel therapeutics for ADPKD.

  5. Regulation of cell death receptor S-nitrosylation and apoptotic signaling by Sorafenib in hepatoblastoma cells.

    PubMed

    Rodríguez-Hernández, A; Navarro-Villarán, E; González, R; Pereira, S; Soriano-De Castro, L B; Sarrias-Giménez, A; Barrera-Pulido, L; Álamo-Martínez, J M; Serrablo-Requejo, A; Blanco-Fernández, G; Nogales-Muñoz, A; Gila-Bohórquez, A; Pacheco, D; Torres-Nieto, M A; Serrano-Díaz-Canedo, J; Suárez-Artacho, G; Bernal-Bellido, C; Marín-Gómez, L M; Barcena, J A; Gómez-Bravo, M A; Padilla, C A; Padillo, F J; Muntané, J

    2015-12-01

    Nitric oxide (NO) plays a relevant role during cell death regulation in tumor cells. The overexpression of nitric oxide synthase type III (NOS-3) induces oxidative and nitrosative stress, p53 and cell death receptor expression and apoptosis in hepatoblastoma cells. S-nitrosylation of cell death receptor modulates apoptosis. Sorafenib is the unique recommended molecular-targeted drug for the treatment of patients with advanced hepatocellular carcinoma. The present study was addressed to elucidate the potential role of NO during Sorafenib-induced cell death in HepG2 cells. We determined the intra- and extracellular NO concentration, cell death receptor expression and their S-nitrosylation modifications, and apoptotic signaling in Sorafenib-treated HepG2 cells. The effect of NO donors on above parameters has also been determined. Sorafenib induced apoptosis in HepG2 cells. However, low concentration of the drug (10nM) increased cell death receptor expression, as well as caspase-8 and -9 activation, but without activation of downstream apoptotic markers. In contrast, Sorafenib (10 µM) reduced upstream apoptotic parameters but increased caspase-3 activation and DNA fragmentation in HepG2 cells. The shift of cell death signaling pathway was associated with a reduction of S-nitrosylation of cell death receptors in Sorafenib-treated cells. The administration of NO donors increased S-nitrosylation of cell death receptors and overall induction of cell death markers in control and Sorafenib-treated cells. In conclusion, Sorafenib induced alteration of cell death receptor S-nitrosylation status which may have a relevant repercussion on cell death signaling in hepatoblastoma cells.

  6. The life and death of a B cell.

    PubMed

    Defrance, Thierry; Casamayor-Pallejà, Montserrat; Krammer, Peter H

    2002-01-01

    Regulation of apoptosis in the B cell lineage has implications for homeostasis, quality control of the antibody response, and tolerance. In this chapter we examine the different checkpoints that control life and death decisions of B cells during the antigen-independent and antigen-dependent phases of their development. We discuss the cell death mechanism involved in elimination of unwanted B cells at different stages of their development as well as the signals that trigger or repress the apoptotic process. At the steady state, before or after development of an immune response, B cell apoptosis ensures that the antigen receptor (BCR) on newly produced B cells is functional and does not recognize self-antigens with high avidity. It also ensures that the size of the peripheral B cell compartment remains constant in spite of the continuous input of B cells from the bone marrow. All these processes are controlled by the mitochondrial death pathway and are thus perturbed by overexpression of the antiapoptotic members of the bcl-2 gene family. By contrast, the death receptor pathway plays a prominent role during the antigen-dependent phase of B cell development. Three sets of membrane molecules stand as crucial regulators of B cell survival. First, the BCR which plays a central but ambiguous role. On the one hand, it triggers death of B cells that recognize self-antigens or have been exposed to repeated antigenic stimulations. On the other hand, it promotes survival of the peripheral mature B cell pool and protects activated B cells from CD95-induced killing. Second, the death receptor Fas/CD95 which is instrumental in censoring B cells activated in a bystander fashion at the initiation of the response to T-dependent antigens. It also drives elimination of low-affinity and self-reactive B cell clones that arise through the process of somatic mutations during the germinal center reaction. As such, it contributes to the affinity maturation of the antibody response. Finally

  7. Therapeutic approaches to preventing cell death in Huntington disease

    PubMed Central

    Kaplan, Anna; Stockwell, Brent R.

    2012-01-01

    Neurodegenerative diseases affect the lives of millions of patients and their families. Due to the complexity of these diseases and our limited understanding of their pathogenesis, the design of therapeutic agents that can effectively treat these diseases has been challenging. Huntington disease (HD) is one of several neurological disorders with few therapeutic options. HD, like numerous other neurodegenerative diseases, involves extensive neuronal cell loss. One potential strategy to combat HD and other neurodegenerative disorders is to intervene in the execution of neuronal cell death. Inhibiting neuronal cell death pathways may slow the development of neurodegeneration. However, discovering small molecule inhibitors of neuronal cell death remains a significant challenge. Here, we review candidate therapeutic targets controlling cell death mechanisms that have been the focus of research in HD, as well as an emerging strategy that has been applied to developing small molecule inhibitors—fragment-based drug discovery (FBDD). FBDD has been successfully used in both industry and academia to identify selective and potent small molecule inhibitors, with a focus on challenging proteins that are not amenable to traditional high-throughput screening approaches. FBDD has been used to generate potent leads, pre-clinical candidates, and has led to the development of an FDA approved drug. This approach can be valuable for identifying modulators of cell-death-regulating proteins; such compounds may prove to be the key to halting the progression of HD and other neurodegenerative disorders. PMID:22967354

  8. Therapeutic approaches to preventing cell death in Huntington disease.

    PubMed

    Kaplan, Anna; Stockwell, Brent R

    2012-12-01

    Neurodegenerative diseases affect the lives of millions of patients and their families. Due to the complexity of these diseases and our limited understanding of their pathogenesis, the design of therapeutic agents that can effectively treat these diseases has been challenging. Huntington disease (HD) is one of several neurological disorders with few therapeutic options. HD, like numerous other neurodegenerative diseases, involves extensive neuronal cell loss. One potential strategy to combat HD and other neurodegenerative disorders is to intervene in the execution of neuronal cell death. Inhibiting neuronal cell death pathways may slow the development of neurodegeneration. However, discovering small molecule inhibitors of neuronal cell death remains a significant challenge. Here, we review candidate therapeutic targets controlling cell death mechanisms that have been the focus of research in HD, as well as an emerging strategy that has been applied to developing small molecule inhibitors-fragment-based drug discovery (FBDD). FBDD has been successfully used in both industry and academia to identify selective and potent small molecule inhibitors, with a focus on challenging proteins that are not amenable to traditional high-throughput screening approaches. FBDD has been used to generate potent leads, pre-clinical candidates, and has led to the development of an FDA approved drug. This approach can be valuable for identifying modulators of cell-death-regulating proteins; such compounds may prove to be the key to halting the progression of HD and other neurodegenerative disorders. PMID:22967354

  9. Solamargine triggers hepatoma cell death through apoptosis

    PubMed Central

    XIE, XIAODONG; ZHU, HAITAO; YANG, HUIJIAN; HUANG, WENSI; WU, YINGYING; WANG, YING; LUO, YANLING; WANG, DONGQING; SHAO, GENBAO

    2015-01-01

    Solamargine (SM), a steroidal alkaloid glycoside extracted from the traditional Chinese herb Solanum incanum, has been evidenced to inhibit the growth and induce apoptosis in a number of human cancer cell lines. In the present study, the anticancer effect of SM and underlying molecular mechanism of SM-induced apoptosis were investigated on the human hepatocellular carcinoma cells, SMMC7721 and HepG2. The proliferation effects of SM on the SMMC7721 and HepG2 cell lines were evaluated using MTT and colony formation assays. In addition, the percentage of apoptosis was measured using an Annexin V/propidium iodide staining method and the cell cycle distribution mediated by SM was analyzed using flow cytometry. The expression levels of B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), caspase-3, caspase-9, proliferating cell nuclear antigen (pcna) and Ki67 proteins were examined to further demonstrate the proliferate and apoptosis effects of SM on the hepatoma cells. The results indicated that SM effectively inhibited hepatoma cell proliferation and promoted apoptosis. SM resulted in cell cycle arrest at the G2/M phase in the two cell lines. In addition, SM downregulated the levels of proliferation-associated (Ki67 and pcna) and anti-apoptotic (Bcl-2) proteins, and promoted the activity of apoptosis-associated proteins (Bax, caspase-3 and caspase-9). Therefore, the activation of the Bcl-2/Bax and caspase signaling pathways may be involved in the SM-induced apoptosis of hepatoma cells. PMID:26170994

  10. Microenvironmental Effects of Cell Death in Malignant Disease.

    PubMed

    Gregory, Christopher D; Ford, Catriona A; Voss, Jorine J L P

    2016-01-01

    Although apoptosis is well recognized as a cell death program with clear anticancer roles, accumulating evidence linking apoptosis with tissue repair and regeneration indicates that its relationship with malignant disease is more complex than previously thought. Here we review how the responses of neighboring cells in the microenvironment of apoptotic tumor cells may contribute to the cell birth/cell death disequilibrium that provides the basis for cancerous tissue emergence and growth. We describe the bioactive properties of apoptotic cells and consider, in particular, how apoptosis of tumor cells can engender a range of responses including pro-oncogenic signals having proliferative, angiogenic, reparatory, and immunosuppressive features. Drawing on the parallels between wound healing, tissue regeneration and cancer, we propose the concept of the "onco-regenerative niche," a cell death-driven generic network of tissue repair and regenerative mechanisms that are hijacked in cancer. Finally, we consider how the responses to cell death in tumors can be targeted to provide more effective and long-lasting therapies. PMID:27558817

  11. Lung epithelial cell death induced by oil-dispersant mixtures.

    PubMed

    Wang, He; Shi, Yongli; Major, Danielle; Yang, Zhanjun

    2012-08-01

    The dispersants used in oil spill disasters are claimed to be safe, but increased solubility of high-molecular-weight components in crude oil is of public health concern. The water-accommodated fractions (WAF) of crude oil mixed with dispersants may become airborne and cause lung epithelial damage when inhaled. This study was designed to examine the cell death and related death pathways of lung epithelial cells in response to WAF. Cultured A549 cells were treated for 2 or 24h with different concentrations of WAF. The WAF was prepared by mixing each of the dispersants (Corexit EC9527A, Corexit EC9500A and Corexit EC9580A) with crude oil for extraction with PBS. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay, lactate dehydrogenase assay, morphology and cleaved caspase 9 protein, and microtubule-associated protein 1 light chain 3 were all used to measure cell viability, necrosis, apoptosis and autophagy quantitation, respectively. Results showed that the WAF of oil-dispersant mixtures caused cell death in the lung epithelial cells, in a dose-dependent manner, with the major cellular pathways of necrosis and apoptosis involved. Autophagy also occurred in cells exposed to WAF mixtures at lower concentrations before any detectable cell death, indicating greater sensitivity to WAF exposure. The three types of cell behavior, namely necrosis, apoptosis and autophagy, may play different roles in oil spill-related respiratory disorders. PMID:22504303

  12. RACK-1 overexpression protects against goniothalamin-induced cell death

    PubMed Central

    Inayat-Hussain, S.H.; Wong, L.T.; Chan, K.M.; Rajab, N.F.; Din, L.B.; Harun, R.; Kizilors, A.; Saxena, N.; Mourtada-Maarabouni, M.; Farzaneh, F.; Williams, G.T.

    2009-01-01

    Goniothalamin, a styryllactone, has been shown to induce cytotoxicity via apoptosis in several tumor cell lines. In this study, we have examined the potential role of several genes, which were stably transfected into T-cell lines and which regulate apoptosis in different ways, on goniothalamin-induced cell death. Overexpression of full-length receptor for activated protein C-kinase 1 (RACK-1) and pc3n3, which up-regulates endogenous RACK-1, in both Jurkat and W7.2 T cells resulted in inhibition of goniothalamin-induced cell death as assessed by MTT and clonogenic assays. However, overexpression of rFau (antisense sequence to Finkel–Biskis–Reilly murine sarcoma virus-associated ubiquitously expressed gene) in W7.2 cells did not confer resistance to goniothalamin-induced cell death. Etoposide, a clinically used cytotoxic agent, was equipotent in causing cytotoxicity in all the stable transfectants. Assessment of DNA damage by Comet assay revealed goniothalamin-induced DNA strand breaks as early as 1 h in vector control but this effect was inhibited in RACK-1 and pc3n3 stably transfected W7.2 cells. This data demonstrate that RACK-1 plays a crucial role in regulating cell death signalling pathways induced by goniothalamin. PMID:19698770

  13. Detection of Apoptotic Versus Autophagic Cell Death by Flow Cytometry.

    PubMed

    Sica, Valentina; Maiuri, M Chiara; Kroemer, Guido; Galluzzi, Lorenzo

    2016-01-01

    Different modes of regulated cell death (RCD) can be initiated by distinct molecular machineries and their morphological manifestations can be difficult to discriminate. Moreover, cells responding to stress often activate an adaptive response centered around autophagy, and whether such a response is cytoprotective or cytotoxic cannot be predicted based on morphological parameters only. Molecular definitions are therefore important to understand various RCD subroutines from a mechanistic perspective. In vitro, various forms of RCD including apoptosis and autophagic cell death can be easily discriminated from each other with assays that involve chemical or pharmacological interventions targeting key components of either pathway. Here, we detail a straightforward method to discriminate apoptosis from autophagic cell death by flow cytometry, based on the broad-spectrum caspase inhibitor Z-VAD-fmk and the genetic inhibition of ATG5.

  14. Porcine circovirus-2 capsid protein induces cell death in PK15 cells

    SciTech Connect

    Walia, Rupali; Dardari, Rkia Chaiyakul, Mark; Czub, Markus

    2014-11-15

    Studies have shown that Porcine circovirus (PCV)-2 induces apoptosis in PK15 cells. Here we report that cell death is induced in PCV2b-infected PK15 cells that express Capsid (Cap) protein and this effect is enhanced in interferon gamma (IFN-γ)-treated cells. We further show that transient PCV2a and 2b-Cap protein expression induces cell death in PK15 cells at rate similar to PCV2 infection, regardless of Cap protein localization. These data suggest that Cap protein may have the capacity to trigger different signaling pathways involved in cell death. Although further investigation is needed to gain deeper insights into the nature of the pathways involved in Cap-induced cell death, this study provides evidence that PCV2-induced cell death in kidney epithelial PK15 cells can be mapped to the Cap protein and establishes the need for future research regarding the role of Cap-induced cell death in PCV2 pathogenesis. - Highlights: • IFN-γ enhances PCV2 replication that leads to cell death in PK15 cells. • IFN-γ enhances nuclear localization of the PCV2 Capsid protein. • Transient PCV2a and 2b-Capsid protein expression induces cell death. • Cell death is not dictated by specific Capsid protein sub-localization.

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

    PubMed

    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.

  16. Technological advances in real-time tracking of cell death

    PubMed Central

    Skommer, Joanna; Darzynkiewicz, Zbigniew; Wlodkowic, Donald

    2010-01-01

    Cell population can be viewed as a quantum system, which like Schrödinger’s cat exists as a combination of survival- and death-allowing states. Tracking and understanding cell-to-cell variability in processes of high spatio-temporal complexity such as cell death is at the core of current systems biology approaches. As probabilistic modeling tools attempt to impute information inaccessible by current experimental approaches, advances in technologies for single-cell imaging and omics (proteomics, genomics, metabolomics) should go hand in hand with the computational efforts. Over the last few years we have made exciting technological advances that allow studies of cell death dynamically in real-time and with the unprecedented accuracy. These approaches are based on innovative fluorescent assays and recombinant proteins, bioelectrical properties of cells, and more recently also on state-of-the-art optical spectroscopy. Here, we review current status of the most innovative analytical technologies for dynamic tracking of cell death, and address the interdisciplinary promises and future challenges of these methods. PMID:20519963

  17. Ceramide path in human lung cell death.

    PubMed

    Chan, C; Goldkorn, T

    2000-04-01

    Lung epithelium plays a significant role in modulating the inflammatory response to lung injury. Airway epithelial cells are targeted by hydrogen peroxide (H(2)O(2)) and oxygen radicals, which are agents commonly produced during inflammatory processes. The mechanisms and molecular sites affected by H(2)O(2) are largely unknown but may involve the induction of sphingomyelin (SM) hydrolysis to generate ceramide, which serves as a second messenger in initiating an apoptotic response. Here we show that exposure of human airway epithelial (HAE) cells to 50 to 100 microM H(2)O(2) induces within 5 to 10 min a greater than 2-fold activation of neutral sphingomyelinase activity with concomitant SM hydrolysis, ceramide generation, and apoptosis. On the other hand, activation of protein kinase C (PKC) by 12-O-tetradecanoylphorbol-13-acetate inhibits both H(2)O(2)-induced ceramide production and apoptosis. The apoptotic response could be restored by the addition of 25 microM cell-permeant C6-ceramide. These findings indicate that ceramide, the product of SM hydrolysis, plays an important role in H(2)O(2)-induced apoptosis in HAE cells, and that PKC counteracts ceramide-mediated apoptosis in these cells. We suggest that the mediation of epithelial cell apoptosis by ceramide and its inhibition by PKC constitute a central mechanism by which inflammatory processes are modulated in the epithelium of the lung.

  18. Identification of the death zone: a spatially restricted region for programmed cell death that sculpts the fly eye.

    PubMed

    Monserrate, J P; Brachmann, C Baker

    2007-02-01

    Programmed cell death (PCD) sculpts many developing tissues. The final patterning step of the Drosophila retina is the elimination, through PCD, of a subset of interommatidial lattice cells during pupation. It is not understood how this process is spatially regulated to ensure that cells die in the proper positions. To address this, we observed PCD of lattice cells in the pupal retina in real time. This live-visualization method demonstrates that lattice cell apoptosis is a highly specific process. In all, 85% of lattice cells die in exclusive 'death zone' positions between adjacent ommatidia. In contrast, cells that make specific contacts with primary pigment cells are protected from death. Two signaling pathways, Drosophila epidermal growth factor receptor (dEgfr) and Notch, that are thought to be central to the regulation of lattice cell survival and death, are not sufficient to establish the death zone. Thus, application of live visualization to the fly eye gives new insight into a dynamic developmental process.

  19. Signal transduction events in aluminum-induced cell death in tomato suspension cells.

    PubMed

    Yakimova, Elena T; Kapchina-Toteva, Veneta M; Woltering, Ernst J

    2007-06-01

    In this study, some of the signal transduction events involved in AlCl(3)-induced cell death in tomato (Lycopersicon esculentum Mill.) suspension cells were elucidated. Cells treated with 100 microM AlCl(3) showed typical features of programmed cell death (PCD) such as nuclear and cytoplasmic condensation. Cell death was effectively inhibited by protease and human caspase inhibitors indicating a cell death execution mechanism with similarities to animal apoptosis. Cell death was suppressed by application of antoxidants and by inhibitors of phospholipase C (PLC), phospholipase D (PLD) and ethylene signalling pathways. The results suggest that low concentrations of heavy metal ions stimulate both PLC and PLD signalling pathways leading to the production of reactive oxygen species (ROS) and subsequent cell death executed by caspase-like proteases.

  20. Cell death and autophagy: cytokines, drugs, and nutritional factors.

    PubMed

    Bursch, Wilfried; Karwan, Anneliese; Mayer, Miriam; Dornetshuber, Julia; Fröhwein, Ulrike; Schulte-Hermann, Rolf; Fazi, Barbara; Di Sano, Federica; Piredda, Lucia; Piacentini, Mauro; Petrovski, Goran; Fésüs, László; Gerner, Christopher

    2008-12-30

    Cells may use multiple pathways to commit suicide. In certain contexts, dying cells generate large amounts of autophagic vacuoles and clear large proportions of their cytoplasm, before they finally die, as exemplified by the treatment of human mammary carcinoma cells with the anti-estrogen tamoxifen (TAM, < or = 1 microM). Protein analysis during autophagic cell death revealed distinct proteins of the nuclear fraction including GST-pi and some proteasomal subunit constituents to be affected during autophagic cell death. Depending on the functional status of caspase-3, MCF-7 cells may switch between autophagic and apoptotic features of cell death [Fazi, B., Bursch, W., Fimia, G.M., Nardacci R., Piacentini, M., Di Sano, F., Piredda, L., 2008. Fenretinide induces autophagic cell death in caspase-defective breast cancer cells. Autophagy 4(4), 435-441]. Furthermore, the self-destruction of MCF-7 cells was found to be completed by phagocytosis of cell residues [Petrovski, G., Zahuczky, G., Katona, K., Vereb, G., Martinet, W., Nemes, Z., Bursch, W., Fésüs, L., 2007. Clearance of dying autophagic cells of different origin by professional and non-professional phagocytes. Cell Death Diff. 14 (6), 1117-1128]. Autophagy also constitutes a cell's strategy of defense upon cell damage by eliminating damaged bulk proteins/organelles. This biological condition may be exemplified by the treatment of MCF-7 cells with a necrogenic TAM-dose (10 microM), resulting in the lysis of almost all cells within 24h. However, a transient (1h) challenge of MCF-7 cells with the same dose allowed the recovery of cells involving autophagy. Enrichment of chaperones in the insoluble cytoplasmic protein fraction indicated the formation of aggresomes, a potential trigger for autophagy. In a further experimental model HL60 cells were treated with TAM, causing dose-dependent distinct responses: 1-5 microM TAM, autophagy predominant; 7-9 microM, apoptosis predominant; 15 microM, necrosis. These phenomena

  1. An Early and Robust Activation of Caspases Heads Cells for a Regulated Form of Necrotic-like Cell Death.

    PubMed

    Garcia-Belinchón, Mercè; Sánchez-Osuna, María; Martínez-Escardó, Laura; Granados-Colomina, Carla; Pascual-Guiral, Sònia; Iglesias-Guimarais, Victoria; Casanelles, Elisenda; Ribas, Judit; Yuste, Victor J

    2015-08-21

    Apoptosis is triggered by the activation of caspases and characterized by chromatin condensation and nuclear fragmentation (type II nuclear morphology). Necrosis is depicted by a gain in cell volume (oncosis), swelling of organelles, plasma membrane leakage, and subsequent loss of intracellular contents. Although considered as different cell death entities, there is an overlap between apoptosis and necrosis. In this sense, mounting evidence suggests that both processes can be morphological expressions of a common biochemical network known as "apoptosis-necrosis continuum." To gain insight into the events driving the apoptosis-necrosis continuum, apoptotically proficient cells were screened facing several apoptotic inducers for the absence of type II apoptotic nuclear morphologies. Chelerythrine was selected for further studies based on its cytotoxicity and the lack of apoptotic nuclear alterations. Chelerythrine triggered an early plasma membrane leakage without condensed chromatin aggregates. Ultrastructural analysis revealed that chelerythrine-mediated cytotoxicity was compatible with a necrotic-like type of cell death. Biochemically, chelerythrine induced the activation of caspases. Moreover, the inhibition of caspases prevented chelerythrine-triggered necrotic-like cell death. Compared with staurosporine, chelerythrine induced stronger caspase activation detectable at earlier times. After using a battery of chemicals, we found that high concentrations of thiolic antioxidants fully prevented chelerythrine-driven caspase activation and necrotic-like cell death. Lower amounts of thiolic antioxidants partially prevented chelerythrine-mediated cytotoxicity and allowed cells to display type II apoptotic nuclear morphology correlating with a delay in caspase-3 activation. Altogether, these data support that an early and pronounced activation of caspases can drive cells to undergo a form of necrotic-like regulated cell death. PMID:26124276

  2. An Early and Robust Activation of Caspases Heads Cells for a Regulated Form of Necrotic-like Cell Death*

    PubMed Central

    Garcia-Belinchón, Mercè; Sánchez-Osuna, María; Martínez-Escardó, Laura; Granados-Colomina, Carla; Pascual-Guiral, Sònia; Iglesias-Guimarais, Victoria; Casanelles, Elisenda; Ribas, Judit; Yuste, Victor J.

    2015-01-01

    Apoptosis is triggered by the activation of caspases and characterized by chromatin condensation and nuclear fragmentation (type II nuclear morphology). Necrosis is depicted by a gain in cell volume (oncosis), swelling of organelles, plasma membrane leakage, and subsequent loss of intracellular contents. Although considered as different cell death entities, there is an overlap between apoptosis and necrosis. In this sense, mounting evidence suggests that both processes can be morphological expressions of a common biochemical network known as “apoptosis-necrosis continuum.” To gain insight into the events driving the apoptosis-necrosis continuum, apoptotically proficient cells were screened facing several apoptotic inducers for the absence of type II apoptotic nuclear morphologies. Chelerythrine was selected for further studies based on its cytotoxicity and the lack of apoptotic nuclear alterations. Chelerythrine triggered an early plasma membrane leakage without condensed chromatin aggregates. Ultrastructural analysis revealed that chelerythrine-mediated cytotoxicity was compatible with a necrotic-like type of cell death. Biochemically, chelerythrine induced the activation of caspases. Moreover, the inhibition of caspases prevented chelerythrine-triggered necrotic-like cell death. Compared with staurosporine, chelerythrine induced stronger caspase activation detectable at earlier times. After using a battery of chemicals, we found that high concentrations of thiolic antioxidants fully prevented chelerythrine-driven caspase activation and necrotic-like cell death. Lower amounts of thiolic antioxidants partially prevented chelerythrine-mediated cytotoxicity and allowed cells to display type II apoptotic nuclear morphology correlating with a delay in caspase-3 activation. Altogether, these data support that an early and pronounced activation of caspases can drive cells to undergo a form of necrotic-like regulated cell death. PMID:26124276

  3. Glycobiology of cell death: when glycans and lectins govern cell fate

    PubMed Central

    Lichtenstein, R G; Rabinovich, G A

    2013-01-01

    Although one typically thinks of carbohydrates as associated with cell growth and viability, glycosylation also has an integral role in many processes leading to cell death. Glycans, either alone or complexed with glycan-binding proteins, can deliver intracellular signals or control extracellular processes that promote initiation, execution and resolution of cell death programs. Herein, we review the role of glycans and glycan-binding proteins as essential components of the cell death machinery during physiologic and pathologic settings. PMID:23703323

  4. Apoptotic photoreceptor cell death in mouse models of retinitis pigmentosa.

    PubMed Central

    Portera-Cailliau, C; Sung, C H; Nathans, J; Adler, R

    1994-01-01

    Retinitis pigmentosa (RP) is a group of inherited human diseases in which photoreceptor degeneration leads to visual loss and eventually to blindness. Although mutations in the rhodopsin, peripherin, and cGMP phosphodiesterase genes have been identified in some forms of RP, it remains to be determined whether these mutations lead to photoreceptor cell death through necrotic or apoptotic mechanisms. In this paper, we report a test of the hypothesis that photoreceptor cell death occurs by an apoptotic mechanism in three mouse models of RP: retinal degeneration slow (rds) caused by a peripherin mutation, retinal degeneration (rd) caused by a defect in cGMP phosphodiesterase, and transgenic mice carrying a rhodopsin Q344ter mutation responsible for autosomal dominant RP. Two complementary techniques were used to detect apoptosis-specific internucleosomal DNA fragmentation: agarose gel electrophoresis and in situ labeling of apoptotic cells by terminal dUTP nick end labeling. Both methods showed extensive apoptosis of photoreceptors in all three mouse models of retinal degeneration. We also show that apoptotic death occurs in the retina during normal development, suggesting that different mechanisms can cause photoreceptor death by activating an intrinsic death program in these cells. These findings raise the possibility that retinal degenerations may be slowed by interfering with the apoptotic mechanism itself. Images PMID:8302876

  5. Oxidative Stress and Programmed Cell Death in Yeast

    PubMed Central

    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

  6. Programmed Cell Death During Female Gametophyte Development

    SciTech Connect

    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

  7. How does metabolism affect cell death in cancer?

    PubMed

    Villa, Elodie; Ricci, Jean-Ehrland

    2016-07-01

    In cancer research, identifying a specificity of tumor cells compared with 'normal' proliferating cells for targeted therapy is often considered the Holy Grail for researchers and clinicians. Although diverse in origin, most cancer cells share characteristics including the ability to escape cell death mechanisms and the utilization of different methods of energy production. In the current paradigm, aerobic glycolysis is considered the central metabolic characteristic of cancer cells (Warburg effect). However, recent data indicate that cancer cells also show significant changes in other metabolic pathways. Indeed, it was recently suggested that Kreb's cycle, pentose phosphate pathway intermediates, and essential and nonessential amino acids have key roles. Renewed interest in the fact that cancer cells have to reprogram their metabolism in order to proliferate or resist treatment must take into consideration the ability of tumor cells to adapt their metabolism to the local microenvironment (low oxygen, low nutrients). This variety of metabolic sources might be either a strength, resulting in infinite possibilities for adaptation and increased ability to resist chemotherapy-induced death, or a weakness that could be targeted to kill cancer cells. Here, we discuss recent insights showing how energetic metabolism may regulate cell death and how this might be relevant for cancer treatment.

  8. Lipopolysaccharide-activated microglia induce death of oligodendrocyte progenitor cells and impede their development.

    PubMed

    Pang, Y; Campbell, L; Zheng, B; Fan, L; Cai, Z; Rhodes, P

    2010-03-17

    Damage to oligodendrocyte (OL) progenitor cells (OPCs) and hypomyelination are two hallmark features of periventricular leukomalacia (PVL), the most common form of brain damage in premature infants. Clinical and animal studies have linked the incidence of PVL to maternal infection/inflammation, and activated microglia have been proposed to play a central role. However, the precise mechanism of how activated microglia adversely affects the survival and development of OPCs is still not clear. Here we demonstrate that lipopolysaccharide (LPS)-activated microglia are deleterious to OPCs, that is, impeding OL lineage progression, reducing the production of myelin basic protein (MBP), and mediating OPC death. We further demonstrate that LPS-activated microglia mediate OPC death by two distinct mechanisms in a time-dependent manner. The early phase of cell damage occurs within 24 h after LPS treatment, which is mediated by nitric oxide (NO)-dependent oxidative damage and is prevented by N(G)-nitro-l-arginine methyl ester (l-NAME), a general inhibitor of nitric oxide synthase. The delayed cell death is evident at 48 h after LPS treatment, is mediated by cytokines, and is prevented by blocking the activity of tumor necrosis factor-alpha (TNF-alpha) and pro-nerve growth factor (proNGF), but not by l-NAME. Furthermore, microglia-derived insulin-like growth factor-1 (IGF-1) and ciliary neurotrophic factor (CNTF) were significantly suppressed by LPS, and exogenous IGF-1 and CNTF synergistically protected OLs from death induced by LPS-treated microglia conditioned medium, indicating that a deficiency in trophic support may also be involved in OL death. Our finding that LPS-activated microglia not only induce two waves of cell death but also greatly impair OL development may shed some light on the mechanisms underlying selective white matter damage and hypomyelination in PVL.

  9. Danger signalling during cancer cell death: origins, plasticity and regulation

    PubMed Central

    Garg, A D; Martin, S; Golab, J; Agostinis, P

    2014-01-01

    Accumulating data indicates that following anti-cancer treatments, cancer cell death can be perceived as immunogenic or tolerogenic by the immune system. The former is made possible due to the ability of certain anti-cancer modalities to induce immunogenic cell death (ICD) that is associated with the emission of damage-associated molecular patterns (DAMPs), which assist in unlocking a sequence of events leading to the development of anti-tumour immunity. In response to ICD inducers, activation of endoplasmic reticulum (ER) stress has been identified to be indispensable to confer the immunogenic character of cancer cell death, due to its ability to coordinate the danger signalling pathways responsible for the trafficking of vital DAMPs and subsequent anti-cancer immune responses. However, in recent times, certain processes apart from ER stress have emerged (e.g., autophagy and possibly viral response-like signature), which have the ability to influence danger signalling. In this review, we discuss the molecular nature, emerging plasticity in the danger signalling mechanisms and immunological impact of known DAMPs in the context of immunogenic cancer cell death. We also discuss key effector mechanisms modulating the interface between dying cancer cells and the immune cells, which we believe are crucial for the therapeutic relevance of ICD in the context of human cancers, and also discuss the influence of experimental conditions and animal models on these. PMID:23686135

  10. Cell death in protists without mitochondria.

    PubMed

    Chose, Olivier; Sarde, Claude-Olivier; Noël, Christophe; Gerbod, Delphine; Jimenez, Juan-Carlos; Brenner, Catherine; Capron, Monique; Viscogliosi, Eric; Roseto, Alberto

    2003-12-01

    Some protozoans, such as Trichomonad species, do not possess mitochondria. Most of the time, they harbor another type of membrane-bounded organelle, called hydrogenosome from its capacity to produce H(2). This is the case for the human parasite Trichomonas vaginalis. Some other parasites, such as the protist Giardia lamblia, do not harbor any of these organelles. From this observation arises naturally a naive question: How do cells die when the mitochondrion, the cornerstone of apoptotic process, is absent? Data strongly suggest that the mitochondrion and the hydrogenosome arose from a common ancestral endosymbiont. But hydrogenosomes do not appear to directly substitute for mitochondria in apoptotic functions. Thus, it appears judicious to examine more closely the genome of unicellular cells, which do not harbor mitochondria, and search for new molecules that could participate in the apoptotic process in these microorganisms. PMID:15033707

  11. Cell death in protists without mitochondria.

    PubMed

    Chose, Olivier; Sarde, Claude-Olivier; Noël, Christophe; Gerbod, Delphine; Jimenez, Juan-Carlos; Brenner, Catherine; Capron, Monique; Viscogliosi, Eric; Roseto, Alberto

    2003-12-01

    Some protozoans, such as Trichomonad species, do not possess mitochondria. Most of the time, they harbor another type of membrane-bounded organelle, called hydrogenosome from its capacity to produce H(2). This is the case for the human parasite Trichomonas vaginalis. Some other parasites, such as the protist Giardia lamblia, do not harbor any of these organelles. From this observation arises naturally a naive question: How do cells die when the mitochondrion, the cornerstone of apoptotic process, is absent? Data strongly suggest that the mitochondrion and the hydrogenosome arose from a common ancestral endosymbiont. But hydrogenosomes do not appear to directly substitute for mitochondria in apoptotic functions. Thus, it appears judicious to examine more closely the genome of unicellular cells, which do not harbor mitochondria, and search for new molecules that could participate in the apoptotic process in these microorganisms.

  12. DAMPs from Cell Death to New Life

    PubMed Central

    Vénéreau, Emilie; Ceriotti, Chiara; Bianchi, Marco Emilio

    2015-01-01

    Our body handles tissue damage by activating the immune system in response to intracellular molecules released by injured tissues [damage-associated molecular patterns (DAMPs)], in a similar way as it detects molecular motifs conserved in pathogens (pathogen-associated molecular patterns). DAMPs are molecules that have a physiological role inside the cell, but acquire additional functions when they are exposed to the extracellular environment: they alert the body about danger, stimulate an inflammatory response, and finally promote the regeneration process. Beside their passive release by dead cells, some DAMPs can be secreted or exposed by living cells undergoing a life-threatening stress. DAMPs have been linked to inflammation and related disorders: hence, inhibition of DAMP-mediated inflammatory responses is a promising strategy to improve the clinical management of infection- and injury-elicited inflammatory diseases. However, it is important to consider that DAMPs are not only danger signals but also central players in tissue repair. Indeed, some DAMPs have been studied for their role in tissue healing after sterile or infection-associated inflammation. This review is focused on two exemplary DAMPs, HMGB1 and adenosine triphosphate, and their contribution to both inflammation and tissue repair. PMID:26347745

  13. DJ-1 protects against cell death following acute cardiac ischemia–reperfusion injury

    PubMed Central

    Dongworth, R K; Mukherjee, U A; Hall, A R; Astin, R; Ong, S-B; Yao, Z; Dyson, A; Szabadkai, G; Davidson, S M; Yellon, D M; Hausenloy, D J

    2014-01-01

    Novel therapeutic targets are required to protect the heart against cell death from acute ischemia–reperfusion injury (IRI). Mutations in the DJ-1 (PARK7) gene in dopaminergic neurons induce mitochondrial dysfunction and a genetic form of Parkinson's disease. Genetic ablation of DJ-1 renders the brain more susceptible to cell death following ischemia–reperfusion in a model of stroke. Although DJ-1 is present in the heart, its role there is currently unclear. We sought to investigate whether mitochondrial DJ-1 may protect the heart against cell death from acute IRI by preventing mitochondrial dysfunction. Overexpression of DJ-1 in HL-1 cardiac cells conferred the following beneficial effects: reduced cell death following simulated IRI (30.4±4.7% with DJ-1 versus 52.9±4.7% in control; n=5, P<0.05); delayed mitochondrial permeability transition pore (MPTP) opening (a critical mediator of cell death) (260±33 s with DJ-1 versus 121±12 s in control; n=6, P<0.05); and induction of mitochondrial elongation (81.3±2.5% with DJ-1 versus 62.0±2.8% in control; n=6 cells, P<0.05). These beneficial effects of DJ-1 were absent in cells expressing the non-functional DJ-1L166P and DJ-1Cys106A mutants. Adult mice devoid of DJ-1 (KO) were found to be more susceptible to cell death from in vivo IRI with larger myocardial infarct sizes (50.9±3.5% DJ-1 KO versus 41.1±2.5% in DJ-1 WT; n≥7, P<0.05) and resistant to cardioprotection by ischemic preconditioning. DJ-1 KO hearts showed increased mitochondrial fragmentation on electron microscopy, although there were no differences in calcium-induced MPTP opening, mitochondrial respiratory function or myocardial ATP levels. We demonstrate that loss of DJ-1 protects the heart from acute IRI cell death by preventing mitochondrial dysfunction. We propose that DJ-1 may represent a novel therapeutic target for cardioprotection. PMID:24577080

  14. Sensory hair cell death and regeneration in fishes.

    PubMed

    Monroe, Jerry D; Rajadinakaran, Gopinath; Smith, Michael E

    2015-01-01

    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 vs. 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.

  15. Sensory hair cell death and regeneration in fishes

    PubMed Central

    Monroe, Jerry D.; Rajadinakaran, Gopinath; Smith, Michael E.

    2015-01-01

    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 vs. 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. PMID:25954154

  16. Deletion of a single allele of the Pex11β gene is sufficient to cause oxidative stress, delayed differentiation and neuronal death in mouse brain

    PubMed Central

    Ahlemeyer, Barbara; Gottwald, Magdalena; Baumgart-Vogt, Eveline

    2012-01-01

    SUMMARY Impaired neuronal migration and cell death are commonly observed in patients with peroxisomal biogenesis disorders (PBDs), and in mouse models of this diseases. In Pex11β-deficient mice, we observed that the deletion of a single allele of the Pex11β gene (Pex11β+/− heterozygous mice) caused cell death in primary neuronal cultures prepared from the neocortex and cerebellum, although to a lesser extent as compared with the homozygous-null animals (Pex11β−/− mice). In corresponding brain sections, cell death was rare, but differences between the genotypes were similar to those found in vitro. Because PEX11β has been implicated in peroxisomal proliferation, we searched for alterations in peroxisomal abundance in the brain of heterozygous and homozygous Pex11β-null mice compared with wild-type animals. Deletion of one allele of the Pex11β gene slightly increased the abundance of peroxisomes, whereas the deletion of both alleles caused a 30% reduction in peroxisome number. The size of the peroxisomal compartment did not correlate with neuronal death. Similar to cell death, neuronal development was delayed in Pex11β+/− mice, and to a further extent in Pex11β−/− mice, as measured by a reduced mRNA and protein level of synaptophysin and a reduced protein level of the mature isoform of MAP2. Moreover, a gradual increase in oxidative stress was found in brain sections and primary neuronal cultures from wild-type to heterozygous to homozygous Pex11β-deficient mice. SOD2 was upregulated in neurons from Pex11β+/− mice, but not from Pex11β−/− animals, whereas the level of catalase remained unchanged in neurons from Pex11β+/− mice and was reduced in those from Pex11β−/− mice, suggesting a partial compensation of oxidative stress in the heterozygotes, but a failure thereof in the homozygous Pex11β−/− brain. In conclusion, we report the alterations in the brain caused by the deletion of a single allele of the Pex11β gene. Our data

  17. Fatal Delayed Haemolytic Transfusion Reaction and Hyperhaemolysis Syndrome in a Pregnant Woman with Sickle Cell Anaemia.

    PubMed

    Asnawi, Asral Wirda Ahmad; Sathar, Jameela; Mohamed, Rashidah; Deraman, Rohayu; Kumaran, Sri; Hamid, Shahada Sobah Abd; Zakaria, Muhd Zanapiah

    2016-06-01

    Clinical manifestations of sickle cell disease (SCD) arise from the tendency of the sickle haemoglobin to polymerize and deform red blood cells into the characteristic sickle shape. Sickle cell crisis is a devastating complication that may occur in patients with SCD. If not managed properly permanent organ damage and even death may be the final outcome. A case of a 32-year-old Nigerian lady, Gravida 1 Para 0 in her first trimester, with SCD who developed signs and symptoms of delayed haemolytic transfusion reaction after receiving packed red cell transfusion is demonstrated. Multiple red cell alloantibodies were detected in the patient's plasma; anti-Fy a, anti-Jk b and anti-E. The patient miscarriaged and succumbed to complications of hyperhaemolysis with delayed haemolytic transfusion reaction, acute chest syndrome and renal failure. There is an urgent need for mandatory red cell antibody screen and identification especially in high-risk cases. Prevention of alloimmunization by supplying phenotype-specific red cells is also required. PMID:27408406

  18. Fatal Delayed Haemolytic Transfusion Reaction and Hyperhaemolysis Syndrome in a Pregnant Woman with Sickle Cell Anaemia.

    PubMed

    Asnawi, Asral Wirda Ahmad; Sathar, Jameela; Mohamed, Rashidah; Deraman, Rohayu; Kumaran, Sri; Hamid, Shahada Sobah Abd; Zakaria, Muhd Zanapiah

    2016-06-01

    Clinical manifestations of sickle cell disease (SCD) arise from the tendency of the sickle haemoglobin to polymerize and deform red blood cells into the characteristic sickle shape. Sickle cell crisis is a devastating complication that may occur in patients with SCD. If not managed properly permanent organ damage and even death may be the final outcome. A case of a 32-year-old Nigerian lady, Gravida 1 Para 0 in her first trimester, with SCD who developed signs and symptoms of delayed haemolytic transfusion reaction after receiving packed red cell transfusion is demonstrated. Multiple red cell alloantibodies were detected in the patient's plasma; anti-Fy a, anti-Jk b and anti-E. The patient miscarriaged and succumbed to complications of hyperhaemolysis with delayed haemolytic transfusion reaction, acute chest syndrome and renal failure. There is an urgent need for mandatory red cell antibody screen and identification especially in high-risk cases. Prevention of alloimmunization by supplying phenotype-specific red cells is also required.

  19. Mechanisms of Cell Death in Acute Liver Failure

    PubMed Central

    Bantel, Heike; Schulze-Osthoff, Klaus

    2012-01-01

    Acute liver failure (ALF) can be the consequence of various etiologies, that might vary between different geographic regions. Most frequent are intoxications with acetaminophen, viral hepatitis, or liver damage of unknown origin. ALF occurs when the extent of hepatocyte death exceeds the regenerative capacity of the liver. The mode of liver cell death that is predominantly induced in ALF, i.e., apoptosis or necrosis, is still controversial and presumably determined by the etiology, duration, and magnitude of liver injury. Severe liver damage involves oxidative stress and depletion of ATP resulting in necrosis. In contrast, maintenance of ATP stores is required for the execution of apoptosis. Recent data suggest that necrosis resulting from severe liver damage is associated with poor outcome of ALF patients. Discrimination between apoptosis and necrosis might be therefore useful for the identification of ALF patients requiring liver transplantation. Identification of the molecular cell death mechanisms remains an important issue not only for early prediction of ALF outcome, but also for therapeutic interventions. In view of the pleiotropic functions of critical mediators of cell death and tissue regeneration, a particular challenge will be to reduce hepatocellular death without inhibiting the regenerative capacity of the liver. Here, we review the molecular mechanisms of hepatocyte injury and the pathways leading to apoptosis and necrosis, which might represent potential diagnostic and therapeutic targets in ALF. PMID:22485095

  20. Lipid raft involvement in yeast cell growth and death.

    PubMed

    Mollinedo, Faustino

    2012-01-01

    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 Cryptococcus 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. Lipid raft involvement in yeast cell growth and death

    PubMed Central

    Mollinedo, Faustino

    2012-01-01

    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 Cryptococcus 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. PMID:23087902

  2. The Endoplasmic Reticulum Binding Protein BiP Displays Dual Function in Modulating Cell Death Events1[W][OPEN

    PubMed Central

    Carvalho, Humberto H.; Silva, Priscila A.; Mendes, Giselle C.; Brustolini, Otávio J.B.; Pimenta, Maiana R.; Gouveia, Bianca C.; Valente, Maria Anete S.; Ramos, Humberto J.O.; Soares-Ramos, Juliana R.L.; Fontes, Elizabeth P.B.

    2014-01-01

    The binding protein (BiP) has been demonstrated to participate in innate immunity and attenuate endoplasmic reticulum- and osmotic stress-induced cell death. Here, we employed transgenic plants with manipulated levels of BiP to assess whether BiP also controlled developmental and hypersensitive programmed cell death (PCD). Under normal conditions, the BiP-induced transcriptome revealed a robust down-regulation of developmental PCD genes and an up-regulation of the genes involved in hypersensitive PCD triggered by nonhost-pathogen interactions. Accordingly, the BiP-overexpressing line displayed delayed leaf senescence under normal conditions and accelerated hypersensitive response triggered by Pseudomonas syringae pv tomato in soybean (Glycine max) and tobacco (Nicotiana tabacum), as monitored by measuring hallmarks of PCD in plants. The BiP-mediated delay of leaf senescence correlated with the attenuation of N-rich protein (NRP)-mediated cell death signaling and the inhibition of the senescence-associated activation of the unfolded protein response (UPR). By contrast, under biological activation of salicylic acid (SA) signaling and hypersensitive PCD, BiP overexpression further induced NRP-mediated cell death signaling and antagonistically inhibited the UPR. Thus, the SA-mediated induction of NRP cell death signaling occurs via a pathway distinct from UPR. Our data indicate that during the hypersensitive PCD, BiP positively regulates the NRP cell death signaling through a yet undefined mechanism that is activated by SA signaling and related to ER functioning. By contrast, BiP’s negative regulation of leaf senescence may be linked to its capacity to attenuate the UPR activation and NRP cell death signaling. Therefore, BiP can function either as a negative or positive modulator of PCD events. PMID:24319082

  3. Autophagonizer, a novel synthetic small molecule, induces autophagic cell death

    SciTech Connect

    Choi, In-Kwon; Cho, Yoon Sun; Jung, Hye Jin; Kwon, Ho Jeong

    2010-03-19

    Autophagy is an apoptosis-independent mechanism of cell death that protects the cell from environmental imbalances and infection by pathogens. We identified a novel small molecule, 2-(3-Benzyl-4-oxo-3,4,5,6,7,8-hexahydro-benzo[4,5]thieno[2,3-d] pyrimidin-2-ylsulfanylmethyl)-oxazole-4-carboxylic acid (2-pyrrolidin-1-yl-ethyl)-amide (referred as autophagonizer), using high-content cell-based screening and the autophagosome marker EGFP-LC3. Autophagonizer inhibited growth and induced cell death in the human tumor cell lines MCF7, HeLa, HCT116, A549, AGS, and HT1080 via a caspase-independent pathway. Conversion of cytosolic LC3-I to autophagosome-associated LC3-II was greatly enhanced by autophagonizer treatment. Transmission electron microscopy and acridine orange staining revealed increased autophagy in the cytoplasm of autophagonizer-treated cells. In conclusion, autophagonizer is a novel autophagy inducer with unique structure, which induces autophagic cell death in the human tumor cell lines.

  4. The metabolism beyond programmed cell death in yeast

    PubMed Central

    Ring, Julia; Sommer, Cornelia; Carmona-Gutierrez, Didac; Ruckenstuhl, Christoph; Eisenberg, Tobias; Madeo, Frank

    2012-01-01

    A cell's reaction to any change in the endogenous or exogenous conditions often involves a complex response that eventually either leads to cell adaptation and survival or to the initiation and execution of (programmed) cell death. The molecular decision whether to live or die, while depending on a cell's genome, is fundamentally influenced by its actual metabolic status. Thus, the collection of all metabolites present in a biological system at a certain time point (the so-called metabolome) defines its physiological, developmental and pathological state and determines its fate during changing and stressful conditions. The budding yeast Saccharomyces cerevisiae is a unicellular organism that allows to easily modify and monitor conditions affecting the cell's metabolome, for instance through a simple change of the nutrition source. Such changes can be used to mimic and study (patho)physiological scenarios, including caloric restriction and longevity, the Warburg effect in cancer cells or changes in mitochondrial mass affecting cell death. In addition, disruption of single genes or generation of respiratory deficiency (via abrogation of mitochondrial DNA) assists in revealing connections between metabolism and apoptosis. In this minireview, we discuss recent studies using the potential of the yeast model to provide new insights into the processes of stress defense, cell death and longevity. PMID:22480867

  5. Ghrelin Inhibits Oligodendrocyte Cell Death by Attenuating Microglial Activation

    PubMed Central

    Lee, Jee Youn

    2014-01-01

    Background Recently, we reported the antiapoptotic effect of ghrelin in spinal cord injury-induced apoptotic cell death of oligodendrocytes. However, how ghrelin inhibits oligodendrocytes apoptosis, is still unknown. Therefore, in the present study, we examined whether ghrelin inhibits microglia activation and thereby inhibits oligodendrocyte apoptosis. Methods Using total cell extracts prepared from BV-2 cells activated by lipopolysaccharide (LPS) with or without ghrelin, the levels of p-p38 phosphor-p38 mitogen-activated protein kinase (p-p38MAPK), phospho-c-Jun N-terminal kinase (pJNK), p-c-Jun, and pro-nerve growth factor (proNGF) were examined by Western blot analysis. Reactive oxygen species (ROS) production was investigated by using dichlorodihydrofluorescein diacetate. To examine the effect of ghrelin on oligodendrocyte cell death, oligodendrocytes were cocultured in transwell chambers of 24-well plates with LPS-stimulated BV-2 cells. After 48 hours incubation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and terminal deoxynucleotidyl transferase 2'-deoxyuridine, 5'-triphosphate nick end labeling staining were assessed. Results Ghrelin treatment significantly decreased levels of p-p38MAPK, p-JNK, p-c-Jun, and proNGF in LPS-stimulated BV-2 cells. ROS production increased in LPS-stimulated BV-2 cells was also significantly inhibited by ghrelin treatment. In addition, ghrelin significantly inhibited oligodendrocyte cell death when cocultured with LPS-stimulated BV-2 cells. Conclusion Ghrelin inhibits oligodendrocyte cell death by decreasing proNGF and ROS production as well as p38MAPK and JNK activation in activated microglia as an anti-inflammatory hormone. PMID:25309797

  6. Measuring Cell Death by Trypan Blue Uptake and Light Microscopy.

    PubMed

    Crowley, Lisa C; Marfell, Brooke J; Christensen, Melinda E; Waterhouse, Nigel J

    2016-01-01

    Trypan blue is a colorimetric dye that stains dead cells with a blue color easily observed using light microscopy at low resolution. The staining procedure is rapid and cells can be analyzed within minutes. The number of live (unstained) and dead (blue) cells can be counted using a hemocytometer on a basic upright microscope. Trypan blue staining is therefore a convenient assay for rapidly determining the overall viability of cells in a culture before commencing scientific experimentation, or for quantitating cell death following treatment with any cytotoxic stimuli. PMID:27371594

  7. Irvalec Inserts into the Plasma Membrane Causing Rapid Loss of Integrity and Necrotic Cell Death in Tumor Cells

    PubMed Central

    Molina-Guijarro, José M.; Macías, Álvaro; García, Carolina; Muñoz, Eva; García-Fernández, Luis F.; David, Miren; Núñez, Lucía; Martínez-Leal, Juan F.; Moneo, Victoria; Cuevas, Carmen; Lillo, M. Pilar; Villalobos Jorge, Carlos; Valenzuela, Carmen; Galmarini, Carlos M.

    2011-01-01

    Irvalec is a marine-derived antitumor agent currently undergoing phase II clinical trials. In vitro, Irvalec induces a rapid loss of membrane integrity in tumor cells, accompanied of a significant Ca2+ influx, perturbations of membrane conductivity, severe swelling and the formation of giant membranous vesicles. All these effects are not observed in Irvalec-resistant cells, or are significantly delayed by pretreating the cells with Zn2+. Using fluorescent derivatives of Irvalec it was demonstrated that the compound rapidly interacts with the plasma membrane of tumor cells promoting lipid bilayer restructuration. Also, FRET experiments demonstrated that Irvalec molecules localize in the cell membrane close enough to each other as to suggest that the compound could self-organize, forming supramolecular structures that likely trigger cell death by necrosis through the disruption of membrane integrity. PMID:21556352

  8. Sudden infant death syndrome: near-weightlessness and delayed neural transformation.

    PubMed

    Reid, G M; Tervit, H M

    1996-04-01

    Dilation of the pulmonary arteries and increased pulmonary blood volume are recorded in sudden infant death syndrome and in infants living at low barometric pressures (high altitude). Low barometric pressure leads to chronic alveolar hypoxia (1,2). There is diversion and loss of body-fluid under conditions of microgravity (near-weightlessness) encountered in human space-travel and prolonged bedrest (3). The condition mimics shock and oligemia (4,5). The human neonate has underdeveloped postural mechanisms and low muscle-power. A transformation begins at about two months of age, which enables the human infant to adapt to the extrauterine environment (6). The neonate resembles the space traveller who, in a near-weightlessness antigravity environment, develops baroreceptor incompetence, visceral and venous congestion and oliguria. The low birthweight infant displays many of the disorders of the space traveller, viz. poor circulation, high blood-glucose, insulin resistance, weak muscles, slow gut absorption and bone demineralization (7-10). These conditions are virtually identical with the internal adjustments the body makes on lying down (negative gravity or near-weightlessness). We discuss the similarities of sudden infant death syndrome to low barometric pressure environment, orthostatic intolerance, the Pickwickian syndrome and X disease.

  9. Curcumin Attenuates Staurosporine-Mediated Death of Retinal Ganglion Cells

    PubMed Central

    Burugula, Balabharathi; Ganesh, Bhagyalaxmi S.

    2011-01-01

    Purpose. Staurosporine (SS) causes retinal ganglion cell (RGC) death in vivo, but the underlying mechanisms have been unclear. Since previous studies on RGC-5 cells indicated that SS induces cell death by elevating proteases, this study was undertaken to investigate whether SS induces RGC loss by elevating proteases in the retina, and curcumin prevents SS-mediated death of RGCs. Methods. Transformed mouse retinal ganglion-like cells (RGC-5) were treated with 2.0 μM SS and various doses of curcumin. Two optimal doses of SS (12.5 and 100 nM) and curcumin (2.5 and 10 μM) were injected into the vitreous of C57BL/6 mice. Matrix metalloproteinase (MMP)-9, tissue plasminogen activator (tPA), and urokinase plasminogen activator (uPA) activities were assessed by zymography assays. Viability of RGC-5 cells was assessed by MTT assays. RGC and amacrine cell loss in vivo was assessed by immunostaining with Brn3a and ChAT antibodies, respectively. Frozen retinal cross sections were immunostained for nuclear factor-κB (NF-κB). Results. Staurosporine induced uPA and tPA levels in RGC-5 cells, and MMP-9, uPA, and tPA levels in the retinas and promoted the death of RGC-5 cells in vitro and RGCs and amacrine cells in vivo. In contrast, curcumin attenuated RGC and amacrine cell loss, despite elevated levels of proteases. An NF-κB inhibitory peptide reversed curcumin-mediated protective effect on RGC-5 cells, but did not inhibit protease levels. Curcumin did not inhibit protease levels in vivo, but attenuated RGC and amacrine cell loss by restoring NF-κB expression. Conclusions. The results show that curcumin attenuates RGC and amacrine cell death despite elevated levels of proteases and raises the possibility that it may be used as a plausible adjuvant therapeutic agent to prevent the loss of these cells in retinal degenerative conditions. PMID:21498608

  10. Chloromethyl chlorosulfate as a voltage delay inhibitor in lithium cells

    SciTech Connect

    Delnick, F.M.

    1991-04-05

    Chloromethyl chlorosulfate (CMCS) is used as a passive film growth inhibitor in electrochemical cells to minimize voltage delay and low-voltage discharge. Film growth on lithium anodes is significantly diminished when CMCS is added to SOCl{sub 2} and SO{sub 2}Cl{sub 2} electrolytes of lithium batteries. The CMCS also has the effect of extending the shelf-life of Li/SOCl{sub 2} and Li/SO{sub 2}Cl{sub 2} batteries.

  11. Chloromethyl chlorosulfate as a voltage delay inhibitor in lithium cells

    DOEpatents

    Delnick, Frank M.

    1993-01-01

    Chloromethyl chlorosulfate (CMCS) is used as a passive film growth inhibitor in electrochemical cells to minimize voltage delay and low-voltage discharge. Film growth on lithium anodes is significantly diminished when CMCS is added to SOCl.sub.2 and SO.sub.2 Cl.sub.2 electrolytes of lithium batteries. The CMCS also has the effect of extending the shelf-life of Li/SOCl.sub.2 and Li/SO.sub.2 Cl.sub.2 batteries.

  12. Chloromethyl chlorosulfate as a voltage delay inhibitor in lithium cells

    DOEpatents

    Delnick, F.M.

    1993-04-13

    Chloromethyl chlorosulfate (CMCS) is used as a passive film growth inhibitor in electrochemical cells to minimize voltage delay and low-voltage discharge. Film growth on lithium anodes is significantly diminished when CMCS is added to SOCl[sub 2] and SO[sub 2]Cl[sub 2] electrolytes of lithium batteries. The CMCS also has the effect of extending the shelf-life of Li/SOCl[sub 2] and Li/SO[sub 2]Cl[sub 2] batteries.

  13. Cell death monitoring using quantitative optical coherence tomography methods

    NASA Astrophysics Data System (ADS)

    Farhat, Golnaz; Yang, Victor X. D.; Kolios, Michael C.; Czarnota, Gregory J.

    2011-03-01

    Cell death is characterized by a series of predictable morphological changes, which modify the light scattering properties of cells. We present a multi-parametric approach to detecting changes in subcellular morphology related to cell death using optical coherence tomography (OCT). Optical coherence tomography data were acquired from acute myeloid leukemia (AML) cells undergoing apoptosis over a period of 48 hours. Integrated backscatter (IB) and spectral slope (SS) were computed from OCT backscatter spectra and statistical parameters were extracted from a generalized gamma (GG) distribution fit to OCT signal intensity histograms. The IB increased by 2-fold over 48 hours with significant increases observed as early as 4 hours. The SS increased in steepness by 2.5-fold with significant changes at 12 hours, while the GG parameters were sensitive to apoptotic changes at 24 to 48 hours. Histology slides indicated nuclear condensation and fragmentation at 24 hours, suggesting the late scattering changes could be related to nuclear structure. A second series of measurements from AML cells treated with cisplatin, colchicine or ionizing radiation suggested that the GG parameters could potentially differentiate between modes of cell death. Distinct cellular morphology was observed in histology slides obtained from cells treated under each condition.

  14. Evidence of apoptotic cell death in HIV encephalitis.

    PubMed Central

    Petito, C. K.; Roberts, B.

    1995-01-01

    The mechanism of cell death in the brains of patients with acquired immune deficiency syndrome was examined in 15 cases, 8 of whom had human immunodeficiency virus (HIV) encephalitis, and in 8 control cases. Postmortem formalin-fixed, paraffin-embedded sections were prepared for routine histology and immunohistochemistry to detect cell-specific antigens. Apoptosis was detected by its morphology and by in situ end labeling of its characteristic oligonucleosomal fragments. Combined in situ end labeling and immunohistochemistry identified specific cell types. Six acquired immune deficiency syndrome brains, 5 of which had HIV encephalitis, contained positive nuclei by in situ end labeling. Co-labeling studies identified the cells as neurons, reactive astrocytes, and, rarely, the multinucleated giant cells of HIV encephalitis. The only control with nuclei positive by in situ end labeling had hepatic encephalopathy and Alzheimer type II astrocytes; the location and absence of cell-specific markers suggested a glial origin for the labeled cells. These results demonstrate that at least some neuronal and astrocytic death in HIV infection occurs by apoptosis. Its stimuli are unknown, but likely candidates include tumor necrosis factor or HIV viral products. Additionally, we hypothesize that apoptotic death of reactive astrocytes may be a normal mechanism whereby the brain removes an excess number of astrocytes that have proliferated after certain types of brain injury. Images Figure 1 Figure 2 Figure 3 Figure 5 Figure 4 PMID:7747806

  15. Calcium and cell death signaling in neurodegeneration and aging.

    PubMed

    Smaili, Soraya; Hirata, Hanako; Ureshino, Rodrigo; Monteforte, Priscila T; Morales, Ana P; Muler, Mari L; Terashima, Juliana; Oseki, Karen; Rosenstock, Tatiana R; Lopes, Guiomar S; Bincoletto, Claudia

    2009-09-01

    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 may lead 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.

  16. Light uncages a copper complex to induce nonapoptotic cell death.

    PubMed

    Kumbhar, Anupa A; Franks, Andrew T; Butcher, Raymond J; Franz, Katherine J

    2013-03-25

    Cu3G is a Cu(II) complex of a photoactive tetradentate ligand that is cleaved upon UV irradiation to release Cu. Here we show that the cytotoxicity of Cu3G increases in response to brief UV stimulation to result in extensive cytoplasmic vacuolization that is indicative of nonapoptotic cell death. PMID:23417227

  17. Hox proteins: sculpting body parts by activating localized cell death.

    PubMed

    Alonso, Claudio R

    2002-11-19

    Hox proteins shape animal structures by eliciting different developmental programs along the anteroposterior body axis. A recent study reveals that the Drosophila Hox protein Deformed directly activates the cell-death-promoting gene reaper to maintain the boundaries between distinct head segments.

  18. Bortezomib induces autophagic death in proliferating human endothelial cells

    SciTech Connect

    Belloni, Daniela; Veschini, Lorenzo; Foglieni, Chiara; Dell'Antonio, Giacomo; Caligaris-Cappio, Federico; Ferrarini, Marina; Ferrero, Elisabetta

    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.

  19. Mitochondrial and Cell Death Mechanisms in Neurodegenerative Diseases

    PubMed Central

    Martin, Lee J.

    2010-01-01

    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. PMID:21258649

  20. PROGRAMMED CELL DEATH IN EXTRAOCULAR MUSCLE TENDON/SCLERA PRECURSORS

    EPA Science Inventory

    Abstract

    Purpose: This study was designed to examine the occurrence of natural cell death in the periocular mesenchyme of mouse embryos.

    Methods: Vital staining with LysoTracker Red and Nile blue sulphate as well as terminal nick end labeling (TUNEL) were utiliz...

  1. Targeting Mitochondria with Avocatin B Induces Selective Leukemia Cell Death.

    PubMed

    Lee, Eric A; Angka, Leonard; Rota, Sarah-Grace; Hanlon, Thomas; Mitchell, Andrew; Hurren, Rose; Wang, Xiao Ming; Gronda, Marcela; Boyaci, Ezel; Bojko, Barbara; Minden, Mark; Sriskanthadevan, Shrivani; Datti, Alessandro; Wrana, Jeffery L; Edginton, Andrea; Pawliszyn, Janusz; Joseph, Jamie W; Quadrilatero, Joe; Schimmer, Aaron D; Spagnuolo, Paul A

    2015-06-15

    Treatment regimens for acute myeloid leukemia (AML) continue to offer weak clinical outcomes. Through a high-throughput cell-based screen, we identified avocatin B, a lipid derived from avocado fruit, as a novel compound with cytotoxic activity in AML. Avocatin B reduced human primary AML cell viability without effect on normal peripheral blood stem cells. Functional stem cell assays demonstrated selectivity toward AML progenitor and stem cells without effects on normal hematopoietic stem cells. Mechanistic investigations indicated that cytotoxicity relied on mitochondrial localization, as cells lacking functional mitochondria or CPT1, the enzyme that facilitates mitochondria lipid transport, were insensitive to avocatin B. Furthermore, avocatin B inhibited fatty acid oxidation and decreased NADPH levels, resulting in ROS-dependent leukemia cell death characterized by the release of mitochondrial proteins, apoptosis-inducing factor, and cytochrome c. This study reveals a novel strategy for selective leukemia cell eradication based on a specific difference in mitochondrial function. PMID:26077472

  2. Metal-accelerated oxidation in plant cell death

    SciTech Connect

    Czuba, M. )

    1993-05-01

    Cadmium and mercury toxicity is further enhanced by external oxidizing conditions O[sub 3] or inherent plant processes. Lepidium sativum L, Lycopersicon esculentum Mill., or Phaseolus vulgaris L, were grown inpeat-lite to maturity under continuous cadmium exposure followed by one oxidant (O[sub 3]-6 hr. 30 pphm) exposure, with or without foliar calcium pretreatments. In comparison, Daucus carota, L and other species grown in a 71-V suspension, with or without 2,4-D were exposed continuously to low levels of methylmercury during exponential growth and analyzed in aggregates of distinct populations. Proteins were extracted and analyzed. Mechanisms of toxicity and eventual cell death are Ca-mediated and involve chloroplast, stomatal-water relations and changes in oxidant-anti-oxidant components in cells. Whether the metal-accelerated oxidative damage proceeds to cell death, depends on the species and its differential biotransformation system and cell association component.

  3. Autophagy and Tubular Cell Death in the Kidney.

    PubMed

    Havasi, Andrea; Dong, Zheng

    2016-05-01

    Many common renal insults such as ischemia and toxic injury primarily target the tubular epithelial cells, especially the highly metabolically active proximal tubular segment. Tubular epithelial cells are particularly dependent on autophagy to maintain homeostasis and respond to stressors. The pattern of autophagy in the kidney has a unique spatial and chronologic signature. Recent evidence has shown that there is complex cross-talk between autophagy and various cell death pathways. This review specifically discusses the interplay between autophagy and cell death in the renal tubular epithelia. It is imperative to review this topic because recent discoveries have improved our mechanistic understanding of the autophagic process and have highlighted its broad clinical applications, making autophagy a major target for drug development. PMID:27339383

  4. A role for c-myc in chemically induced renal-cell death.

    PubMed Central

    Zhan, Y; Cleveland, J L; Stevens, J L

    1997-01-01

    A variety of genes, including c-myc, are activated by chemical toxicants in vivo and in vitro. Although enforced c-myc expression induces apoptosis after withdrawing survival factors, it is not clear if activation of the endogenous c-myc gene is an apoptotic signal after toxicant exposure. The renal tubular epithelium is a target for many toxicants. c-myc expression is activated by tubular damage. In quiescent LLC-PK1 renal epithelial cells, c-myc but not max or mad mRNA is induced by the nephrotoxicant S-(1,2-dichlorovinyl)-L-cysteine (DCVC). The kinetics of DCVC-induced c-myc expression and apoptosis suggested an association between cell death and prolonged activation of c-myc expression after toxicant exposure. Accordingly, prolonged activation of an estrogen receptor-Myc fusion construct, but not a construct in which a c-Myc transactivation domain had been deleted, was sufficient to induce apoptosis in LLC-PK1 cells. Moreover, under conditions in which necrosis was the predominant cell death pathway caused by DCVC in parental cells, overexpressing c-myc biased the cell death pathway toward apoptosis. DCVC also induced ornithine decarboxylase (odc) mRNA and activated the odc promoter. Activation of the odc promoter by DCVC required consensus c-Myc-Max binding sites in odc intron 1. Inhibiting ODC activity with alpha-difluoromethylornithine delayed DCVC-induced cell death. Therefore, odc is a target gene in the DCVC apoptotic pathway involving c-myc activation and contributes to apoptosis. Finally, a structurally related cytotoxic but nongenotoxic analog of DCVC did not induce c-myc and did not activate the odc promoter or induce apoptosis. The data support the hypothesis that activation of apoptotic cell death in quiescent renal epithelial cells involves induction of c-myc. This is the first study to demonstrate that c-myc induction by a specific nephrotoxicant leads to gene activation and cell death. PMID:9343440

  5. Ceramide Synthase-dependent Ceramide Generation and Programmed Cell Death

    PubMed Central

    Mullen, Thomas D.; Jenkins, Russell W.; Clarke, Christopher J.; Bielawski, Jacek; Hannun, Yusuf A.; Obeid, Lina M.

    2011-01-01

    The sphingolipid ceramide has been widely implicated in the regulation of programmed cell death or apoptosis. The accumulation of ceramide has been demonstrated in a wide variety of experimental models of apoptosis and in response to a myriad of stimuli and cellular stresses. However, the detailed mechanisms of its generation and regulatory role during apoptosis are poorly understood. We sought to determine the regulation and roles of ceramide production in a model of ultraviolet light-C (UV-C)-induced programmed cell death. We found that UV-C irradiation induces the accumulation of multiple sphingolipid species including ceramide, dihydroceramide, sphingomyelin, and hexosylceramide. Late ceramide generation was also found to be regulated by Bcl-xL, Bak, and caspases. Surprisingly, inhibition of de novo synthesis using myriocin or fumonisin B1 resulted in decreased overall cellular ceramide levels basally and in response to UV-C, but only fumonisin B1 inhibited cell death, suggesting the presence of a ceramide synthase (CerS)-dependent, sphingosine-derived pool of ceramide in regulating programmed cell death. We found that this pool did not regulate the mitochondrial pathway, but it did partially regulate activation of caspase-7 and, more importantly, was necessary for late plasma membrane permeabilization. Attempting to identify the CerS responsible for this effect, we found that combined knockdown of CerS5 and CerS6 was able to decrease long-chain ceramide accumulation and plasma membrane permeabilization. These data identify a novel role for CerS and the sphingosine salvage pathway in regulating membrane permeability in the execution phase of programmed cell death. PMID:21388949

  6. Anoikis: a necessary death program for anchorage-dependent cells.

    PubMed

    Chiarugi, Paola; Giannoni, Elisa

    2008-12-01

    Cell to matrix adhesion is a key factor for cellular homeostasis and disruption of such interaction has adverse effects on cell survival. It leads to a specific type of apoptosis known as "anoikis" in most non-transformed cell types. This kind of apoptosis following loss of cell anchorage is important for development, tissue homeostasis and several diseases. Integrins sense mechanical forces arising from the matrix, thereby converting these stimuli to downstream signals modulating cell viability. Anchorage-independent growth is a crucial step during tumorigenesis and in particular during the metastatic spreading of cancer cells. The disruption of the tight control leading an "homeless" cell to death is therefore able to violate the cell defences against transformation. This review analyses the recent investigations into the molecular mechanisms governing anoikis, discussing the different ways in which adhesion can influence this process and addressing the relevance of this unique apoptosis mode in the development of metastatic cancers, as well as in other diseases.

  7. Game theory in the death galaxy: interaction of cancer and stromal cells in tumour microenvironment.

    PubMed

    Wu, Amy; Liao, David; Tlsty, Thea D; Sturm, James C; Austin, Robert H

    2014-08-01

    Preventing relapse is the major challenge to effective therapy in cancer. Within the tumour, stromal (ST) cells play an important role in cancer progression and the emergence of drug resistance. During cancer treatment, the fitness of cancer cells can be enhanced by ST cells because their molecular signalling interaction delays the drug-induced apoptosis of cancer cells. On the other hand, competition among cancer and ST cells for space or resources should not be ignored. We explore the population dynamics of multiple myeloma (MM) versus bone marrow ST cells by using an experimental microecology that we call the death galaxy, with a stable drug gradient and connected microhabitats. Evolutionary game theory is a quantitative way to capture the frequency-dependent nature of interactive populations. Therefore, we use evolutionary game theory to model the populations in the death galaxy with the gradients of pay-offs and successfully predict the future densities of MM and ST cells. We discuss the possible clinical use of such analysis for predicting cancer progression.

  8. Imipramine protects mouse hippocampus against tunicamycin-induced cell death.

    PubMed

    Ono, Yoko; Shimazawa, Masamitsu; Ishisaka, Mitsue; Oyagi, Atsushi; Tsuruma, Kazuhiro; Hara, Hideaki

    2012-12-01

    Endoplasmic reticulum (ER) stress is implicated in various diseases. Recently, some reports have suggested that the sigma-1 receptor may play a role in ER stress, and many antidepressants have a high affinity for the sigma-1 receptor. In the present study, we focused on imipramine, a widely used antidepressant, and investigated whether it might protect against the neuronal cell death induced by tunicamycin, an ER stress inducer. In mouse cultured hippocampal HT22 cells, imipramine inhibited cell death and caspase-3 activation induced by tunicamycin, although it did not alter the elevated expressions of 78 kDa glucose-regulated protein (GRP78) and C/EBP-homologous protein (CHOP). Interestingly, in such cells application of imipramine normalized the expression of the sigma-1 receptor, which was decreased by treatment with tunicamycin alone. Additionally, NE-100, a selective sigma-1 receptor antagonist, abolished the protective effect of imipramine against such tunicamycin-induced cell death. Imipramine inhibited the reduction of mitochondrial membrane potential induced by tunicamycin, and NE-100 blocked this modulating effect of imipramine. Furthermore, in anesthetized mice intracerebroventricular administration of tunicamycin decreased the number of neuronal cells in the hippocampus, particularly in the CA1 and dentate gyrus (DG) areas, and 7 days' imipramine treatment (10mg/kg/day; i.p.) significantly suppressed these reductions in CA1 and DG. These findings suggest that imipramine protects against ER stress-induced hippocampal neuronal cell death both in vitro and in vivo. Such protection may be partly due to the sigma-1 receptor.

  9. Loss of Urokinase Receptor Sensitizes Cells to DNA Damage and Delays DNA Repair

    PubMed Central

    Narayanaswamy, Pavan B.; Hodjat, Mahshid; Haller, Hermann; Dumler, Inna; Kiyan, Yulia

    2014-01-01

    DNA damage induced by numerous exogenous or endogenous factors may have irreversible consequences on the cell leading to cell cycle arrest, senescence and cell death. The DNA damage response (DDR) is powerful signaling machinery triggered in response to DNA damage, to provide DNA damage recognition, signaling and repair. Most anticancer drugs induce DNA damage, and DNA repair in turn attenuates therapeutic efficiency of those drugs. Approaches delaying DNA repair are often used to increase efficiency of treatment. Recent data show that ubiquitin-proteasome system is essential for signaling and repair of DNA damage. However, mechanisms providing regulation of proteasome intracellular localization, activity, and recruitment to DNA damage sites are elusive. Even less investigated are the roles of extranuclear signaling proteins in these processes. In this study, we report the involvement of the serine protease urokinase-type plasminogen activator receptor (uPAR) in DDR-associated regulation of proteasome. We show that in vascular smooth muscle cells (VSMC) uPAR activates DNA single strand break repair signaling pathway. We provide evidence that uPAR is essential for functional assembly of the 26S proteasome. We further demonstrate that uPAR mediates DNA damage-induced phosphorylation, nuclear import, and recruitment of the regulatory subunit PSMD6 to proteasome. We found that deficiency of uPAR and PSMD6 delays DNA repair and leads to decreased cell survival. These data may offer new therapeutic approaches for diseases such as cancer, cardiovascular and neurodegenerative disorders. PMID:24987841

  10. A Conserved Core of Programmed Cell Death Indicator Genes Discriminates Developmentally and Environmentally Induced Programmed Cell Death in Plants.

    PubMed

    Olvera-Carrillo, Yadira; Van Bel, Michiel; Van Hautegem, Tom; Fendrych, Matyáš; Huysmans, Marlies; Simaskova, Maria; van Durme, Matthias; Buscaill, Pierre; Rivas, Susana; S Coll, Nuria; Coppens, Frederik; Maere, Steven; Nowack, Moritz K

    2015-12-01

    A plethora of diverse programmed cell death (PCD) processes has been described in living organisms. In animals and plants, different forms of PCD play crucial roles in development, immunity, and responses to the environment. While the molecular control of some animal PCD forms such as apoptosis is known in great detail, we still know comparatively little about the regulation of the diverse types of plant PCD. In part, this deficiency in molecular understanding is caused by the lack of reliable reporters to detect PCD processes. Here, we addressed this issue by using a combination of bioinformatics approaches to identify commonly regulated genes during diverse plant PCD processes in Arabidopsis (Arabidopsis thaliana). Our results indicate that the transcriptional signatures of developmentally controlled cell death are largely distinct from the ones associated with environmentally induced cell death. Moreover, different cases of developmental PCD share a set of cell death-associated genes. Most of these genes are evolutionary conserved within the green plant lineage, arguing for an evolutionary conserved core machinery of developmental PCD. Based on this information, we established an array of specific promoter-reporter lines for developmental PCD in Arabidopsis. These PCD indicators represent a powerful resource that can be used in addition to established morphological and biochemical methods to detect and analyze PCD processes in vivo and in planta.

  11. Case reports: delayed hemolytic transfusion reaction in sickle cell disease.

    PubMed

    Syed, S K; Sears, D A; Werch, J B; Udden, M M; Milam, J D

    1996-10-01

    This article reports the details of delayed hemolytic transfusion reactions in four patients with sickle cell disease. These cases demonstrate the characteristics of the reactions, the significant risks involved, and the principles useful in diagnosis and treatment. Patients with sickle cell disease are at particular risk for delayed hemolytic transfusion reactions because they may be transfused at intervals over many years; they frequently form alloantibodies because of antigenic differences from the donor population; and they may receive emergency care in different hospitals where transfusion records are not available. In addition, exchange transfusions, which are often used for patients with sickle cell disease and which were given in three of these cases, raise the risks through increased exposure to foreign erythrocyte antigens and through an increased volume of erythrocytes susceptible to hemolysis. It was concluded that the hazards of these transfusion reactions justify preventive measures, such as extended erythrocyte phenotyping of patients with sickle cell disease and extended phenotypic matching of transfused cells. PMID:8853066

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

    PubMed Central

    Estacion, Mark; Schilling, William P

    2002-01-01

    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. PMID:11825342

  13. Lead-induced cell death in testes of young rats.

    PubMed

    Adhikari, N; Sinha, N; Narayan, R; Saxena, D K

    2001-01-01

    Lead is a well-documented testicular toxicant. The present work was planned to study the occurrence of germ cell death after lead administration. Young growing rats were treated with 5, 10 and 20 mg kg(-1) body weight of lead for 2 weeks. Cell death was assessed by employing in situ TUNEL staining, DNA electrophoresis and morphological examination of the tubules. The results showed that Pb induced significant numbers of germ cells to undergo apoptosis in the seminiferous tubules of rats treated with 20 mg kg(-1) body weight. However, DNA fragmentation was not detected at any of the doses. The level of lead accumulation in the testis increased in a dose-dependent manner. PMID:11481659

  14. Glycosphingolipids and cell death: One aim, many ways

    PubMed Central

    Garcia-Ruiz, Carmen; Morales, Albert; Fernández-Checa, José C.

    2015-01-01

    Glycosphingolipids (GSLs) are a family of bioactive lipids that in addition to their role in the regulation of structural properties of membrane bilayers have emerged as crucial players in many biological processes and signal transduction pathways. Rather than being uniformly distributed within membrane bilayers, GSLs are localized in selective domains called lipid rafts where many signaling platforms operate. One of the most important functions of GSLs, particularly ceramide, is their ability to regulate cell death pathways and hence cell fate. This complex role is accomplished by the ability of GSLs to act in distinct subcellular strategic centers, such as mitochondria, endoplasmic reticulum (ER) or lysosomes to mediate apoptosis, ER stress, autophagy, lysosomal membrane permeabilization and necroptosis. Hence better understanding the role of GSLs in cell death may be of relevance for a number of pathological processes and diseases, including neurodegeneration, metabolic liver diseases and cancer. PMID:25637183

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

    PubMed Central

    Garg, Abhishek D.; Galluzzi, Lorenzo; Apetoh, Lionel; Baert, Thais; Birge, Raymond B.; Bravo-San Pedro, José Manuel; Breckpot, Karine; Brough, David; Chaurio, Ricardo; Cirone, Mara; Coosemans, An; Coulie, Pierre G.; De Ruysscher, Dirk; Dini, Luciana; de Witte, Peter; Dudek-Peric, Aleksandra M.; Faggioni, Alberto; Fucikova, Jitka; Gaipl, Udo S.; Golab, Jakub; Gougeon, Marie-Lise; Hamblin, Michael R.; Hemminki, Akseli; Herrmann, Martin; Hodge, James W.; Kepp, Oliver; Kroemer, Guido; Krysko, Dmitri V.; Land, Walter G.; Madeo, Frank; Manfredi, Angelo A.; Mattarollo, Stephen R.; Maueroder, Christian; Merendino, Nicolò; Multhoff, Gabriele; Pabst, Thomas; Ricci, Jean-Ehrland; Riganti, Chiara; Romano, Erminia; Rufo, Nicole; Smyth, Mark J.; Sonnemann, Jürgen; Spisek, Radek; Stagg, John; Vacchelli, Erika; Vandenabeele, Peter; Vandenberk, Lien; Van den Eynde, Benoit J.; Van Gool, Stefaan; Velotti, Francesca; Zitvogel, Laurence; Agostinis, Patrizia

    2015-01-01

    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 the 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 phenomenon, and identify future challenges for this rapidly expanding field of investigation. PMID:26635802

  16. Aquatic viruses induce host cell death pathways and its application.

    PubMed

    Reshi, Latif; Wu, Jen-Leih; Wang, Hao-Ven; Hong, Jiann-Ruey

    2016-01-01

    Virus infections of mammalian and animal cells consist of a series of events. As intracellular parasites, viruses rely on the use of host cellular machinery. Through the use of cell culture and molecular approaches over the past decade, our knowledge of the biology of aquatic viruses has grown exponentially. The increase in aquaculture operations worldwide has provided new approaches for the transmission of aquatic viruses that include RNA and DNA viruses. Therefore, the struggle between the virus and the host for control of the cell's death machinery is crucial for survival. Viruses are obligatory intracellular parasites and, as such, must modulate apoptotic pathways to control the lifespan of their host to complete their replication cycle. This paper updates the discussion on the detailed mechanisms of action that various aquatic viruses use to induce cell death pathways in the host, such as Bad-mediated, mitochondria-mediated, ROS-mediated and Fas-mediated cell death circuits. Understanding how viruses exploit the apoptotic pathways of their hosts may provide great opportunities for the development of future potential therapeutic strategies and pathogenic insights into different aquatic viral diseases.

  17. Methylglyoxal induces mitochondrial dysfunction and cell death in liver.

    PubMed

    Seo, Kyuhwa; Ki, Sung Hwan; Shin, Sang Mi

    2014-09-01

    Degradation of glucose is aberrantly increased in hyperglycemia, which causes various harmful effects on the liver. Methylglyoxal is produced during glucose degradation and the levels of methylglyoxal are increased in diabetes patients. In this study we investigated whether methylglyoxal induces mitochondrial impairment and apoptosis in HepG2 cells and induces liver toxicity in vivo. Methylglyoxal caused apoptotic cell death in HepG2 cells. Moreover, methylglyoxal significantly promoted the production of reactive oxygen species (ROS) and depleted glutathione (GSH) content. Pretreatment with antioxidants caused a marked decrease in methylglyoxal-induced apoptosis, indicating that oxidant species are involved in the apoptotic process. Methylglyoxal treatment induced mitochondrial permeability transition, which represents mitochondrial impairment. However, pretreatment with cyclosporin A, an inhibitor of the formation of the permeability transition pore, partially inhibited methylglyoxal-induced cell death. Furthermore, acute treatment of mice with methylglyoxal increased the plasma levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), indicating liver toxicity. Collectively, our results showed that methylglyoxal increases cell death and induces liver toxicity, which results from ROS-mediated mitochondrial dysfunction and oxidative stress. PMID:25343013

  18. Megasporogenesis and programmed cell death in Tillandsia (Bromeliaceae).

    PubMed

    Papini, Alessio; Mosti, Stefano; Milocani, Eva; Tani, Gabriele; Di Falco, Pietro; Brighigna, Luigi

    2011-10-01

    The degeneration of three of four meiotic products is a very common process in the female gender of oogamous eukaryotes. In Tillandsia (and many other angiosperms), the surviving megaspore has a callose-free wall in chalazal position while the other three megaspores are completely embedded in callose. Therefore, nutrients and signals can reach more easily the functional megaspore from the nucellus through the chalazal pole with respect to the other megaspores. The abortion of three of four megaspores was already recognized as the result of a programmed cell death (PCD) process. We investigated the process to understand the modality of this specific type of PCD and its relationship to the asymmetric callose deposition around the tetrad. The decision on which of the four megaspores will be the supernumerary megaspores in angiosperms, and hence destined to undergo programmed cell death, appears to be linked to the callose layer deposition around the tetrad. During supernumerary megaspores degeneration, events leading to the deletion of the cells do not appear to belong to a single type of cell death. The first morphological signs are typical of autophagy, including the formation of autophagosomes. The TUNEL positivity and a change in morphology of mitochondria and chloroplasts indicate the passage to an apoptotic-like PCD phase, while the cellular remnants undergo a final process resembling at least partially (ER swelling) necrotic morphological syndromes, eventually leading to a mainly lipidic cell corpse still separated from the functional megaspore by a callose layer.

  19. Cell death and survival signalling in the cardiovascular system.

    PubMed

    Tucka, Joanna; Bennett, Martin; Littlewood, Trevor

    2012-01-01

    The loss of cells is an important factor in many diseases, including those of the cardiovascular system. Whereas apoptosis is an essential process in development and tissue homeostasis, its occurrence is often associated with various pathologies. Apoptosis of neurons that fail to make appropriate connections is essential for the selection of correct neural signalling in the developing embryo, but its appearance in adults is often associated with neurodegenerative disease. Similarly, in the cardiovascular system, remodeling of the mammalian outflow tract during the transition from a single to dual series circulation with four chambers is accompanied by a precise pattern of cell death, but apoptosis of cardiomyocytes contributes to ischemia-reperfusion injury in the heart. In many cases, it is unclear whether apoptosis represents a causative association or merely a consequence of the disease itself. There are many excellent reviews on cell death in the cardiovascular system (1-5); in this review we outline the critical signalling pathways that promote the survival of cardiovascular cells, and their relevance to both physiological cell death and disease.

  20. Bcl-xL controls a switch between cell death modes during mitotic arrest

    PubMed Central

    Bah, N; Maillet, L; Ryan, J; Dubreil, S; Gautier, F; Letai, A; Juin, P; Barillé-Nion, S

    2014-01-01

    Antimitotic agents such as microtubule inhibitors (paclitaxel) are widely used in cancer therapy while new agents blocking mitosis onset are currently in development. All these agents impose a prolonged mitotic arrest in cancer cells that relies on sustained activation of the spindle assembly checkpoint and may lead to subsequent cell death by incompletely understood molecular events. We have investigated the role played by anti-apoptotic Bcl-2 family members in the fate of mitotically arrested mammary tumor cells treated with paclitaxel, or depleted in Cdc20, the activator of the anaphase promoting complex. Under these conditions, a weak and delayed mitotic cell death occurs that is caspase- and Bax/Bak-independent. Moreover, BH3 profiling assays indicate that viable cells during mitotic arrest are primed to die by apoptosis and that Bcl-xL is required to maintain mitochondrial integrity. Consistently, Bcl-xL depletion, or treatment with its inhibitor ABT-737 (but not with the specific Bcl-2 inhibitor ABT-199), during mitotic arrest converts cell response to antimitotics to efficient caspase and Bax-dependent apoptosis. Apoptotic priming under conditions of mitotic arrest relies, at least in part, on the phosphorylation on serine 62 of Bcl-xL, which modulates its interaction with Bax and its sensitivity to ABT-737. The phospho-mimetic S62D-Bcl-xL mutant is indeed less efficient than the corresponding phospho-deficient S62A-Bcl-xL mutant in sequestrating Bax and in protecting cancer cells from mitotic cell death or yeast cells from Bax-induced growth inhibition. Our results provide a rationale for combining Bcl-xL targeting to antimitotic agents to improve clinical efficacy of antimitotic strategy in cancer therapy. PMID:24922075

  1. DNA methylation and differential gene regulation in photoreceptor cell death

    PubMed Central

    Farinelli, P; Perera, A; Arango-Gonzalez, B; Trifunovic, D; Wagner, M; Carell, T; Biel, M; Zrenner, E; Michalakis, S; Paquet-Durand, F; Ekström, P A R

    2014-01-01

    Retinitis pigmentosa (RP) defines a group of inherited degenerative retinal diseases causing progressive loss of photoreceptors. To this day, RP is still untreatable and rational treatment development will require a thorough understanding of the underlying cell death mechanisms. Methylation of the DNA base cytosine by DNA methyltransferases (DNMTs) is an important epigenetic factor regulating gene expression, cell differentiation, cell death, and survival. Previous studies suggested an involvement of epigenetic mechanisms in RP, and in this study, increased cytosine methylation was detected in dying photoreceptors in the rd1, rd2, P23H, and S334ter rodent models for RP. Ultrastructural analysis of photoreceptor nuclear morphology in the rd1 mouse model for RP revealed a severely altered chromatin structure during retinal degeneration that coincided with an increased expression of the DNMT isozyme DNMT3a. To identify disease-specific differentially methylated DNA regions (DMRs) on a genomic level, we immunoprecipitated methylated DNA fragments and subsequently analyzed them with a targeted microarray. Genome-wide comparison of DMRs between rd1 and wild-type retina revealed hypermethylation of genes involved in cell death and survival as well as cell morphology and nervous system development. When correlating DMRs with gene expression data, we found that hypermethylation occurred alongside transcriptional repression. Consistently, motif analysis showed that binding sites of several important transcription factors for retinal physiology were hypermethylated in the mutant model, which also correlated with transcriptional silencing of their respective target genes. Finally, inhibition of DNMTs in rd1 organotypic retinal explants using decitabine resulted in a substantial reduction of photoreceptor cell death, suggesting inhibition of DNA methylation as a potential novel treatment in RP. PMID:25476906

  2. Alpha-toxin induces programmed cell death of human T cells, B cells, and monocytes during USA300 infection.

    PubMed

    Nygaard, Tyler K; Pallister, Kyler B; DuMont, Ashley L; DeWald, Mark; Watkins, Robert L; Pallister, Erik Q; Malone, Cheryl; Griffith, Shannon; Horswill, Alexander R; Torres, Victor J; Voyich, Jovanka M

    2012-01-01

    This investigation examines the influence of alpha-toxin (Hla) during USA300 infection of human leukocytes. Survival of an USA300 isogenic deletion mutant of hla (USA300Δhla) in human blood was comparable to the parental wild-type strain and polymorphonuclear leukocyte (PMN) plasma membrane permeability caused by USA300 did not require Hla. Flow cytometry analysis of peripheral blood mononuclear cells (PBMCs) following infection by USA300, USA300Δhla, and USA300Δhla transformed with a plasmid over-expressing Hla (USA300Δhla Comp) demonstrated this toxin plays a significant role inducing plasma membrane permeability of CD14(+), CD3(+), and CD19(+) PBMCs. Rapid plasma membrane permeability independent of Hla was observed for PMNs, CD14(+) and CD19(+) PBMCs following intoxication with USA300 supernatant while the majority of CD3(+) PBMC plasma membrane permeability induced by USA300 required Hla. Addition of recombinant Hla to USA300Δhla supernatant rescued CD3(+) and CD19(+) PBMC plasma membrane permeability generated by USA300 supernatant. An observed delay in plasma membrane permeability caused by Hla in conjunction with Annexin V binding and ApoBrdU Tunel assays examining PBMCs intoxicated with recombinant Hla or infected with USA300, USA300Δhla, USA300Δhla Comp, and USA300ΔsaeR/S suggest Hla induces programmed cell death of monocytes, B cells, and T cells that results in plasma membrane permeability. Together these findings underscore the importance of Hla during S. aureus infection of human tissue and specifically demonstrate Hla activity during USA300 infection triggers programmed cell death of human monocytes, T cells and B cells that leads to plasma membrane permeability.

  3. Sensitization of acute lymphoblastic leukemia cells for LCL161-induced cell death by targeting redox homeostasis.

    PubMed

    Haß, Christina; Belz, Katharina; Schoeneberger, Hannah; Fulda, Simone

    2016-04-01

    Disturbed redox homeostasis with both elevated reactive oxygen species (ROS) levels and antioxidant defense mechanisms has been reported in acute lymphoblastic leukemia (ALL). We therefore hypothesized that inhibition of pathways responsible for ROS detoxification renders ALL cells more susceptible for cell death. Here, we report that pharmacological inhibitors of key pathways for the elimination of ROS, i.e. Erastin, buthionine sulfoximine (BSO) and Auranofin, sensitize ALL cells for cell death upon treatment with the Smac mimetic LCL161 that antagonizes Inhibitor of Apoptosis (IAP) proteins. Erastin, BSO or Auranofin significantly increase LCL161-induced cell death and also act in concert with LCL161 to profoundly suppress long-term clonogenic survival in several ALL cell lines. Erastin or BSO cooperates with LCL161 to stimulate ROS production and lipid peroxidation prior to cell death. ROS production and lipid peroxidation are required for this cotreatment-induced cell death, since ROS scavengers or pharmacological inhibition of lipid peroxidation provides significant protection against cell death. These results emphasize that inhibition of antioxidant defense mechanisms can serve as a potent approach to prime ALL cells for LCL161-induced cell death.

  4. Disaster, Deprivation and Death: Large but delayed infant mortality in the wake of Filipino tropical cyclones

    NASA Astrophysics Data System (ADS)

    Anttila-Hughes, J. K.; Hsiang, S. M.

    2011-12-01

    Tropical cyclones are some of the most disastrous and damaging of climate events, and estimates of their destructive potential abound in the natural and social sciences. Nonetheless, there have been few systematic estimates of cyclones' impact on children's health. This is concerning because cyclones leave in their wake a swath of asset losses and economic deprivation, both known to be strong drivers of poor health outcomes among children. In this paper we provide a household-level estimate of the effect of tropical cyclones on infant mortality in the Philippines, a country with one of the most active cyclone climatologies in the world. We reconstruct historical cyclones with detailed spatial and temporal resolution, allowing us to estimate the multi-year effects of cyclones on individuals living in specific locations. We combine the cyclone reconstruction with woman-level fertility and mortality data from four waves of the Filipino Demographic and Health Survey, providing birth histories for over 55,000 women. In multiple regressions that control for year and region fixed effects as well as intra-annual climate variation, we find that there is a pronounced and robust increase in female infant mortality among poor families in the 12-24 months after storms hit. The estimated mortality rate among this demographic subgroup is much larger than official mortality rates reported by the Filipino government immediately after storms, implying that much of a cyclone's human cost arrives well after the storm has passed. We find that high infant mortality rates are associated with declines in poor families' income and expenditures, including consumption of food and medical services, suggesting that the mechanism by which these deaths are effected may be economic deprivation. These results indicate that a major health and welfare impact of storms has been thus far overlooked, but may be easily prevented through appropriately targeted income support policies.

  5. Intracellular Delivery of Synthetic dsRNA to Leukemic Cells Induces Apoptotic and Necrotic Cell Death.

    PubMed

    Mahmud, S M; Mek, K J; Idris, A

    2016-01-01

    The type of tumour cell death dictates the type of adaptive immune response mounted against the tumours. In haematological malignancies such as acute myeloid leukaemia (AML), immune evasion due to the poor immunogenicity of leukemic cells is a major hurdle in generating an effective immune response. Transfection of synthetic dsRNA, poly I:C, into leukemic cells to trigger tumour cell death and enhance immunogenicity of the tumour is a promising immunotherapeutic approach. However, the temporal cell death kinetics of poly I:C-electroporated AML cells has not been thoroughly investigated. Electroporation of U937 cells, a human AML cell line, with a high dose of poly I:C resulted in cytotoxicity as early as 1 h post-transfection. Flow cytometric analysis revealed the temporal switch from early apoptosis to late apoptosis/secondary necrosis in poly I:C-electroporated cells in which the nuclear morphology at later time points was consistent with necrotic cell death. Our brief findings demonstrated the temporal cell death kinetics of dsRNA-transfected leukemic cells. This finding is an important development in the field of dsRNA immunotherapy for leukaemia as understanding the type of cell death elicited by transfected dsRNA will dictate the type of immune response to be directed against leukemic cells. PMID:27187041

  6. Programmed cell death and clearance of cell corpses in Caenorhabditis elegans.

    PubMed

    Wang, Xiaochen; Yang, Chonglin

    2016-06-01

    Programmed cell death is critical to the development of diverse animal species from C. elegans to humans. In C. elegans, the cell death program has three genetically distinguishable phases. During the cell suicide phase, the core cell death machinery is activated through a protein interaction cascade. This activates the caspase CED-3, which promotes numerous pro-apoptotic activities including DNA degradation and exposure of the phosphatidylserine "eat me" signal on the cell corpse surface. Specification of the cell death fate involves transcriptional activation of the cell death initiator EGL-1 or the caspase CED-3 by coordinated actions of specific transcription factors in distinct cell types. In the cell corpse clearance stage, recognition of cell corpses by phagocytes triggers several signaling pathways to induce phagocytosis of apoptotic cell corpses. Cell corpse-enclosing phagosomes ultimately fuse with lysosomes for digestion of phagosomal contents. This article summarizes our current knowledge about programmed cell death and clearance of cell corpses in C. elegans. PMID:27048817

  7. Cell death induced by the Alternaria mycotoxin Alternariol.

    PubMed

    Bensassi, Fatma; Gallerne, Cindy; Sharaf El Dein, Ossama; Hajlaoui, Mohamed Rabeh; Bacha, Hassen; Lemaire, Christophe

    2012-09-01

    Mycotoxins are unavoidable contaminants of most foods and feeds, and some are known to be detrimental to human health. It is thus worthwhile to understand how cells of the intestinal system, one of the primary targets of these toxins, respond to their toxic effects. In this study, human colon carcinoma cells were used to elucidate the cell death mode and the pathways triggered by Alternariol (AOH), the most important mycotoxin produced by Alternaria species, which are the most common mycoflora infecting small grain cereals worldwide. Treatment of cells with AOH resulted in a loss of cell viability by inducing apoptosis. AOH-induced apoptosis was mediated through a mitochondria-dependent pathway, characterized by a p53 activation, an opening of the mitochondrial permeability transition pore (PTP), a loss of mitochondrial transmembrane potential (ΔΨm), a downstream generation of O(2)(*-) and caspase 9 and 3 activation. Besides, deficiency of the pro-apoptotic protein Bax partially protected cells against AOH-induced mitochondrial alterations. In addition, experiments performed on purified mitochondria indicated that AOH does not directly target this organelle to induce cell death. Our results demonstrate for the first time that AOH-induced cytotoxicity is mediated by activation of the mitochondrial pathway of apoptosis in human colon carcinoma cells.

  8. [Selective "death programs" or pleiotropic"life programs"? Looking for programmed cell death in the light of evolution].

    PubMed

    Ameisen, Jean-Claude

    2005-01-01

    "Nothing in biology makes sense except in the light of evolution", wrote Theodosius Dobzhansky, one of the founders of the Modern Synthesis that led to the unification of evolutionary theory and genetics in the midst of the 20th century. Programmed cell death is a genetically regulated process of cell suicide that is central to the development, homeostasis and integrity of multicellular organisms. Conversely, the dysregulation of mechanisms controlling cell suicide plays a role in the pathogenesis of a wide range of diseases. While great progress has been achieved in the unveiling of the molecular mechanisms of programmed cell death, a new, and somehow puzzling level of complexity has recently begun to emerge, suggesting i) that several different self destruction pathways may exist and operate in parallel in our cells, and ii) that molecular effectors of cell suicide might also perform other functions unrelated to cell death induction and crucial to cell survival, such as cell differentiation, metabolism, and the regulation of the cell cycle. These new findings, with important physiopathological and therapeutic implications, seem at odds with the paradigm of programmed cell death derived from the studies of Caenorhabditis elegans, which led to the concept of the existence of selective, bona fide death genes that emerged and became selected for their sole capacity to execute or repress cell death. In this review, I will argue that this new level of complexity might only make sense and be understood when considered in a broader evolutionary context than that of our phylogenetic divergence from C. elegans. A new view of the regulated cell death pathways emerges when one attempts to ask the question of when and how they may have become selected during a timeline of 4 billion years, at the level of ancestral single-celled organisms, including the bacteria. I will argue that there may be no such thing as a bona fide genetic cell death program. Rather, in the framework of

  9. Hypoxia-induced cell death and changes in hypoxia-inducible factor-1 activity in PC12 cells upon exposure to nerve growth factor.

    PubMed

    Charlier, Nico; Leclere, Norbert; Felderhoff, Ursula; Heldt, Julia; Kietzmann, Thomas; Obladen, Michael; Gross, Johann

    2002-07-15

    The transcription factor hypoxia-inducible factor-1 (HIF-1) strongly contributes to the expression of adaptive genes under hypoxic conditions. In addition, HIF-1 has been implicated in the regulation of delayed neuronal cell death. Suspension-grown and adherent PC12 cells treated with NGF were used as an experimental model for studying the relationship between hypoxia-induced cell death and activation of HIF-1. Cell damage was assessed by flow cytometry of double-stained (Annexin V and propidiumiodide) cells, and by analysis of the overall death parameters LDH and mitochondrial dehydrogenase. In parallel, cells were transfected with a control and a three-hypoxia-responsive-elements (HRE)-containing vector and HIF-1-driven luciferase activity was determined. Exposure of NGF-treated PC12 cells to hypoxia resulted in a higher cell death rate when compared to untreated controls. PC12 cells exposed for 2 days to NGF exhibited a decrease of HIF-1 activity up to a factor of ten. This decrease may contribute to the enhanced hypoxia-induced cell death via reduced expression of HIF-1alpha-regulated genes responsible for adaptation to hypoxia, like those for glucose transport proteins and enzymes of the glycolytic chain. The decrease in HIF-1 activity and the increase in hypoxia sensitivity may suggest that NGF act as an hierarchically organized signaling molecule.

  10. Glucose Levels in Culture Medium Determine Cell Death Mode in MPP+-treated Dopaminergic Neuronal Cells

    PubMed Central

    Yoon, So-Young

    2015-01-01

    We previously demonstrated that 1-methyl-4-phenylpyridinium (MPP+) causes caspase-independent, non-apoptotic death of dopaminergic (DA) neuronal cells. Here, we specifically examined whether change of glucose concentration in culture medium may play a role for determining cell death modes of DA neurons following MPP+ treatment. By incubating MN9D cells in medium containing varying concentrations of glucose (5~35 mM), we found that cells underwent a distinct cell death as determined by morphological and biochemical criteria. At 5~10 mM glucose concentration (low glucose levels), MPP+ induced typical of the apoptotic dell death accompanied with caspase activation and DNA fragmentation as well as cell shrinkage. In contrast, MN9D cells cultivated in medium containing more than 17.5 mM (high glucose levels) did not demonstrate any of these changes. Subsequently, we observed that MPP+ at low glucose levels but not high glucose levels led to ROS generation and subsequent JNK activation. Therefore, MPP+-induced cell death only at low glucose levels was significantly ameliorated following co-treatment with ROS scavenger, caspase inhibitor or JNK inhibitor. We basically confirmed the quite similar pattern of cell death in primary cultures of DA neurons. Taken together, our results suggest that a biochemically distinct cell death mode is recruited by MPP+ depending on extracellular glucose levels. PMID:26412968

  11. In vitro apoptotic cell death during erythroid differentiation.

    PubMed

    Zamai, L; Burattini, S; Luchetti, F; Canonico, B; Ferri, P; Melloni, E; Gonelli, A; Guidotti, L; Papa, S; Falcieri, E

    2004-03-01

    Erythropoiesis occurs in bone marrow and it has been shown that during in vivo erythroid differentiation some immature erythroblasts undergo apoptosis. In this regard, it is known that immature erythroblasts are FasL- and TRAIL-sensitive and can be killed by cells expressing these ligand molecules. In the present study, we have investigated the cell death phenomenon that occurs during a common unilineage model of erythroid development. Purified CD34+ human haemopoietic progenitors were cultured in vitro in the presence of SCF, IL-3 and erythropoietin. Their differentiation stages and apoptosis were followed by multiple technical approaches. Flow cytometric evaluation of surface and intracellular molecules revealed that glycophorin A appeared at day 3-4 of incubation and about 75% of viable cells co-expressed high density glycophorin A (Gly(bright)) and adult haemoglobin at day 14 of culture, indicating that this system reasonably recapitulates in vivo normal erythropoiesis. Interestingly, when mature (Gly(bright)) erythroid cells reached their higher percentages (day 14) almost half of cultured cells were apoptotic. Morphological studies indicated that the majority of dead cells contained cytoplasmic granular material typical of basophilic stage, and DNA analysis by flow cytometry and TUNEL reaction revealed nuclear fragmentation. These observations indicate that in vitro unilineage erythroid differentiation, as in vivo, is associated with apoptotic cell death of cells with characteristics of basophilic erythroblasts. We suggest that the interactions between different death receptors on immature basophilic erythroblasts with their ligands on more mature erythroblasts may contribute to induce apoptosis in vitro. PMID:15004520

  12. Dual induction of apoptotic and autophagic cell death by targeting survivin in head neck squamous cell carcinoma.

    PubMed

    Zhang, L; Zhang, W; Wang, Y-F; Liu, B; Zhang, W-F; Zhao, Y-F; Kulkarni, A B; Sun, Z-J

    2015-01-01

    Survivin is ubiquitously expressed in patients with head neck squamous cell carcinoma (HNSCC) and is associated with poor survival and chemotherapy resistance. Sepantronium bromide (YM155) is a selective survivin suppressant that exhibits potent antitumor activities by inducing apoptosis and autophagy in various types of cancer. However, the curative effects and underlying mechanisms of YM155 in HNSCC remain unclear. This study showed that survivin overexpression positively correlated with p-S6, p-Rb and LAMP2 but negatively correlated with the autophagic marker LC3 in human HNSCC tissues. In vitro studies revealed that YM155 triggered apoptosis of HNSCC cells in mitochondria and death receptor-dependent manner. The treatment also significantly enhanced autophagy by upregulating Beclin1, which led to cell death. YM155 not only downregulated the expression of survivin but also remarkably suppressed the activation of the mTOR signaling pathway in vitro and in vivo. YM155 displayed potent antitumor activities in both CAL27 xenograft and transgenic HNSCC mice models by delaying tumor onset and suppressing tumor growth. Furthermore, YM155 combined with docetaxel promoted tumor regression better than either treatment alone without causing considerable body weight loss in the HNSCC xenograft models. Overall, targeting survivin by YM155 can benefit HNSCC therapy by increasing apoptotic and autophagic cell death, and suppressing prosurvival pathways. PMID:26018732

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

    PubMed

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

    2015-09-01

    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. PMID:26402700

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

    PubMed Central

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

    2015-01-01

    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. PMID:26402700

  15. Morphine Enhances HIV-1SF162-Mediated Neuron Death and Delays Recovery of Injured Neurites

    PubMed Central

    Masvekar, Ruturaj R.; El-Hage, Nazira; Hauser, Kurt F.; Knapp, Pamela E.

    2014-01-01

    HIV-1 enters the CNS soon after initial systemic infection; within the CNS parenchyma infected and/or activated perivascular macrophages, microglia and astrocytes release viral and cellular toxins that drive secondary toxicity in neurons and other cell types. Our previous work has largely modeled HIV-neuropathology using the individual viral proteins Tat or gp120, with murine striatal neurons as targets. To model disease processes more closely, the current study uses supernatant from HIV-1-infected cells. Supernatant from HIV-1SF162-infected differentiated-U937 cells (HIV+sup) was collected and p24 level was measured by ELISA to assess the infection. Injection drug abuse is a significant risk factor for HIV-infection, and opiate drug abusers show increased HIV-neuropathology, even with anti-retroviral treatments. We therefore assessed HIV+sup effects on neuronal survival and neurite growth/pruning with or without concurrent exposure to morphine, an opiate that preferentially acts through µ-opioid receptors. Effects of HIV+sup ± morphine were assessed on neuronal populations, and also by time-lapse imaging of individual cells. HIV+sup caused dose-dependent toxicity over a range of p24 levels (10–500 pg/ml). Significant interactions occurred with morphine at lower p24 levels (10 and 25 pg/ml), and GSK3β was implicated as a point of convergence. In the presence of glia, selective neurotoxic measures were significantly enhanced and interactions with morphine were also augmented, perhaps related to a decreased level of BDNF. Importantly, the arrest of neurite growth that occurred with exposure to HIV+sup was reversible unless neurons were continuously exposed to morphine. Thus, while reducing HIV-infection levels may be protective, ongoing exposure to opiates may limit recovery. Opiate interactions observed in this HIV-infective environment were similar, though not entirely concordant, with Tat/gp120 interactions reported previously, suggesting unique interactions

  16. Vanadium pentoxide induces activation and death of endothelial cells.

    PubMed

    Montiel-Dávalos, Angélica; Gonzalez-Villava, Adriana; Rodriguez-Lara, Vianey; Montaño, Luis Felipe; Fortoul, Teresa I; López-Marure, Rebeca

    2012-01-01

    Vanadium is a transition metal released into the atmosphere, as air-suspended particles, as a result of the combustion of fossil fuels and some metallurgic industry activities. Air-suspended particle pollution causes inflammation-related processes such as thrombosis and other cardiovascular events. Our aim was to evaluate the effect of vanadium pentoxide (V2O5) on endothelial cells since they are key participants in the pathogenesis of several cardiovascular and inflammatory diseases. Cell adhesion, the expression of adhesion molecules and oxidative stress, as well as proliferation, morphology and cell death of human umbilical vein endothelial cells (HUVECs) exposed to V2O5, were evaluated. Vanadium pentoxide at a 3.12 µg cm(-2) concentration induced an enhanced adhesion of the U937 macrophage cell line to HUVECs, owing to an increased expression of late adhesion molecules. HUVECs exposed to V2O5 showed an increase in ROS and nitric oxide production, and a diminished proliferation. These changes in vanadium-treated HUVECs were accompanied by severe morphological changes and apoptotic cell death. Vanadium pentoxide induced serious endothelial cell damage, probably related to the increased cardiovascular morbidity and mortality observed in individuals living in highly air-polluted areas. PMID:21721017

  17. Alcohol-induced cell death in the embryo.

    PubMed

    Smith, S M

    1997-01-01

    Exposure to alcohol during gestation can have profound consequences, but not all cells within the embryo are affected equally. Recent advances in molecular embryology have allowed an exploration of this variation. Much of this research has focused on the embryo's vulnerability to the facial malformations characteristic of fetal alcohol syndrome. Studies using mice and chicks show that alcohol exposure at specific stages of early embryo development results in significant death among the cells destined to give rise to facial structures (i.e., cranial neural crest cells). This type of cell death is through activation of the cell's own "self-destruct" machinery (i.e., apoptosis). Researchers have advanced several theories to explain how alcohol triggers apoptosis in the neural crest cells. These theories include deficiency in a type of vitamin A compound, retinoic acid; reduced levels of antioxidant compounds (i.e., free radical scavengers) that protect against damage from toxic oxygen molecules (i.e., free radicals); and interference with the cell's normal internal communication pathways. PMID:15706739

  18. Molecular mechanisms of cell death in intervertebral disc degeneration (Review)

    PubMed Central

    ZHANG, FAN; ZHAO, XUELING; SHEN, HONGXING; ZHANG, CAIGUO

    2016-01-01

    Intervertebral discs (IVDs) are complex structures that consist of three parts, namely, nucleus pulposus, annulus fibrosus and cartilage endplates. With aging, IVDs gradually degenerate as a consequence of many factors, such as microenvironment changes and cell death. Human clinical trial and animal model studies have documented that cell death, particularly apoptosis and autophagy, significantly contribute to IVD degeneration. The mechanisms underlying this phenomenon include the activation of apoptotic pathways and the regulation of autophagy in response to nutrient deprivation and multiple stresses. In this review, we briefly summarize recent progress in understanding the function and regulation of apoptosis and autophagy signaling pathways. In particular, we focus on studies that reveal the functional mechanisms of these pathways in IVD degeneration. PMID:27121482

  19. Physical modalities inducing immunogenic tumor cell death for cancer immunotherapy

    PubMed Central

    Adkins, Irena; Fucikova, Jitka; Garg, Abhishek D; Agostinis, Patrizia; Špíšek, Radek

    2015-01-01

    The concept of immunogenic cancer cell death (ICD), as originally observed during the treatment with several chemotherapeutics or ionizing irradiation, has revolutionized the view on the development of new anticancer therapies. ICD is defined by endoplasmic reticulum (ER) stress response, reactive oxygen species (ROS) generation, emission of danger-associated molecular patterns and induction of antitumor immunity. Here we describe known and emerging cancer cell death-inducing physical modalities, such as ionizing irradiation, ultraviolet C light, Photodynamic Therapy (PDT) with Hypericin, high hydrostatic pressure (HHP) and hyperthermia (HT), which have been shown to elicit effective antitumor immunity. We discuss the evidence of ICD induced by these modalities in cancer patients together with their applicability in immunotherapeutic protocols and anticancer vaccine development. PMID:25964865

  20. Cytofluorometric Quantification of Cell Death Elicited by NLR Proteins.

    PubMed

    Sica, Valentina; Manic, Gwenola; Kroemer, Guido; Vitale, Ilio; Galluzzi, Lorenzo

    2016-01-01

    Nucleotide-binding domain and leucine-rich repeat containing (NLR) proteins, also known as NOD-like receptors, are critical components of the molecular machinery that senses intracellular danger signals to initiate an innate immune response against invading pathogens or endogenous sources of hazard. The best characterized effect of NLR signaling is the secretion of various cytokines with immunostimulatory effects, including interleukin (IL)-1β and IL-18. Moreover, at least under specific circumstances, NLRs can promote regulated variants of cell death. Here, we detail two protocols for the cytofluorometric quantification of cell death-associated parameters that can be conveniently employed to assess the lethal activity of specific NLRs or their ligands.

  1. Mitochondria, calcium and cell death: A deadly triad in neurodegeneration

    PubMed Central

    Celsi, Fulvio; Pizzo, Paola; Brini, Marisa; Leo, Sara; Fotino, Carmen; Pinton, Paolo; Rizzuto, Rosario

    2009-01-01

    Mitochondrial Ca2+ accumulation is a tightly controlled process, in turn regulating functions as diverse as aerobic metabolism and induction of cell death. The link between Ca2+ (dys)regulation, mitochondria and cellular derangement is particularly evident in neurodegenerative disorders, in which genetic models and environmental factors allowed to identify common traits in the pathogenic routes. We will here summarize: i) the current view of mechanisms and functions of mitochondrial Ca2+ homeostasis, ii) the basic principles of organelle Ca2+ transport, iii) the role of Ca2+ in neuronal cell death, and iv) the new information on the pathogenesis of Alzheimer's, Huntington's and Parkinson's diseases, highlighting the role of Ca2+ and mitochondria. PMID:19268425

  2. Identification of a mitotic death signature in cancer cell lines.

    PubMed

    Sakurikar, Nandini; Eichhorn, Joshua M; Alford, Sarah E; Chambers, Timothy C

    2014-02-28

    This study examined the molecular mechanism of action of anti-mitotic drugs. The hypothesis was tested that death in mitosis occurs through sustained mitotic arrest with robust Cdk1 signaling causing complete phosphorylation of Mcl-1 and Bcl-xL, and conversely, that mitotic slippage is associated with incomplete phosphorylation of Mcl-1/Bcl-xL. The results, obtained from studying six different cancer cell lines, strongly support the hypothesis and identify for the first time a unique molecular signature for mitotic death. The findings represent an important advance in understanding anti-mitotic drug action and provide insight into cancer cell susceptibility to such drugs which has important clinical implications. PMID:24099917

  3. Identification of a mitotic death signature in cancer cell lines.

    PubMed

    Sakurikar, Nandini; Eichhorn, Joshua M; Alford, Sarah E; Chambers, Timothy C

    2014-02-28

    This study examined the molecular mechanism of action of anti-mitotic drugs. The hypothesis was tested that death in mitosis occurs through sustained mitotic arrest with robust Cdk1 signaling causing complete phosphorylation of Mcl-1 and Bcl-xL, and conversely, that mitotic slippage is associated with incomplete phosphorylation of Mcl-1/Bcl-xL. The results, obtained from studying six different cancer cell lines, strongly support the hypothesis and identify for the first time a unique molecular signature for mitotic death. The findings represent an important advance in understanding anti-mitotic drug action and provide insight into cancer cell susceptibility to such drugs which has important clinical implications.

  4. Programmed cell death in plants: lessons from bacteria?

    PubMed Central

    Wang, Junhui; Bayles, Kenneth W.

    2012-01-01

    Programmed cell death (PCD) has well-established roles in the development and physiology of animals, plants, and fungi. Although aspects of PCD control appear evolutionarily conserved between these organisms, the extent of conservation remains controversial. Recently, a putative bacterial PCD protein homolog in plants was found to play a significant role in cell death control, indicating a conservation of function between these highly divergent organisms. Interestingly, these bacterial proteins are thought to be evolutionarily linked to the Bcl-2 family of proteins. In this Opinion article, we propose a new unifying model to describe the relationship between bacterial and plant PCD systems and propose that the underlying control of PCD is conserved across at least three Kingdoms of life. PMID:23083702

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

    SciTech Connect

    Marrero, Maria Teresa; Estevez, Sara; Negrin, Gledy; Quintana, Jose; Leon, Francisco; Estevez, Francisco

    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.

  6. Orexin A attenuates palmitic acid-induced hypothalamic cell death.

    PubMed

    Duffy, Cayla M; Nixon, Joshua P; Butterick, Tammy A

    2016-09-01

    Palmitic acid (PA), an abundant dietary saturated fatty acid, contributes to obesity and hypothalamic dysregulation in part through increase in oxidative stress, insulin resistance, and neuroinflammation. Increased production of reactive oxygen species (ROS) as a result of PA exposure contributes to the onset of neuronal apoptosis. Additionally, high fat diets lead to changes in hypothalamic gene expression profiles including suppression of the anti-apoptotic protein B cell lymphoma 2 (Bcl-2) and upregulation of the pro-apoptotic protein B cell lymphoma 2 associated X protein (Bax). Orexin A (OXA), a hypothalamic peptide important in obesity resistance, also contributes to neuroprotection. Prior studies have demonstrated that OXA attenuates oxidative stress induced cell death. We hypothesized that OXA would be neuroprotective against PA induced cell death. To test this, we treated an immortalized hypothalamic cell line (designated mHypoA-1/2) with OXA and PA. We demonstrate that OXA attenuates PA-induced hypothalamic cell death via reduced caspase-3/7 apoptosis, stabilization of Bcl-2 gene expression, and reduced Bax/Bcl-2 gene expression ratio. We also found that OXA inhibits ROS production after PA exposure. Finally, we show that PA exposure in mHypoA-1/2 cells significantly reduces basal respiration, maximum respiration, ATP production, and reserve capacity. However, OXA treatment reverses PA-induced changes in intracellular metabolism, increasing basal respiration, maximum respiration, ATP production, and reserve capacity. Collectively, these results support that OXA protects against PA-induced hypothalamic dysregulation, and may represent one mechanism through which OXA can ameliorate effects of obesogenic diet on brain health. PMID:27449757

  7. Detection of programmed cell death using fluorescence energy transfer.

    PubMed Central

    Xu, X; Gerard, A L; Huang, B C; Anderson, D C; Payan, D G; Luo, Y

    1998-01-01

    Fluorescence energy transfer (FRET) can be generated when green fluorescent protein (GFP) and blue fluorescent protein (BFP) are covalently linked together by a short peptide. Cleavage of this linkage by protease completely eliminates FRET effect. Caspase-3 (CPP32) is an important cellular protease activated during programmed cell death. An 18 amino acid peptide containing CPP32 recognition sequence, DEVD, was used to link GFP and BFP together. CPP32 activation can be monitored by FRET assay during the apoptosis process. PMID:9518501

  8. Calcium oxalate toxicity in renal epithelial cells: the mediation of crystal size on cell death mode.

    PubMed

    Sun, X-Y; Gan, Q-Z; Ouyang, J-M

    2015-01-01

    The cytotoxicity of calcium oxalate (CaOx) in renal epithelial cells has been studied extensively, but the cell death mode induced by CaOx with different physical properties, such as crystal size and crystal phase, has not been studied in detail. In this study, we comparatively investigated the differences of cell death mode induced by nano-sized (50 nm) and micron-sized (10 μm) calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) to explore the cell death mechanism. The effect of the exposure of nano-/micron-sized COM and COD crystals toward the African green monkey renal epithelial (Vero) cells were investigated by detecting cell cytoskeleton changes, lysosomal integrity, mitochondrial membrane potential (Δψm), apoptosis and/or necrosis, osteopontin (OPN) expression, and malondialdehyde (MDA) release. Nano-/micron-sized COM and COD crystals could cause apoptosis and necrosis simultaneously. Nano-sized crystals primarily caused apoptotic cell death, leading to cell shrinkage, phosphatidylserine ectropion, and nuclear shrinkage, whereas micron-sized crystals primarily caused necrotic cell death, leading to cell swelling and cell membrane and lysosome rupture. Nano-sized COM and COD crystals induced much greater cell death (sum of apoptosis and necrosis) than micron-sized crystals, and COM crystals showed higher cytotoxicity than the same-sized COD crystals. Both apoptosis and necrosis could lead to mitochondria depolarization and elevate the expression of OPN and the generation of lipid peroxidation product MDA. The amount of expressed OPN and generated MDA was positively related to cell injury degree. The physicochemical properties of crystals could affect the cell death mode. The results of this study may provide a basis for future studies on cell death mechanisms.

  9. Calcium oxalate toxicity in renal epithelial cells: the mediation of crystal size on cell death mode

    PubMed Central

    Sun, X-Y; Gan, Q-Z; Ouyang, J-M

    2015-01-01

    The cytotoxicity of calcium oxalate (CaOx) in renal epithelial cells has been studied extensively, but the cell death mode induced by CaOx with different physical properties, such as crystal size and crystal phase, has not been studied in detail. In this study, we comparatively investigated the differences of cell death mode induced by nano-sized (50 nm) and micron-sized (10 μm) calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) to explore the cell death mechanism. The effect of the exposure of nano-/micron-sized COM and COD crystals toward the African green monkey renal epithelial (Vero) cells were investigated by detecting cell cytoskeleton changes, lysosomal integrity, mitochondrial membrane potential (Δψm), apoptosis and/or necrosis, osteopontin (OPN) expression, and malondialdehyde (MDA) release. Nano-/micron-sized COM and COD crystals could cause apoptosis and necrosis simultaneously. Nano-sized crystals primarily caused apoptotic cell death, leading to cell shrinkage, phosphatidylserine ectropion, and nuclear shrinkage, whereas micron-sized crystals primarily caused necrotic cell death, leading to cell swelling and cell membrane and lysosome rupture. Nano-sized COM and COD crystals induced much greater cell death (sum of apoptosis and necrosis) than micron-sized crystals, and COM crystals showed higher cytotoxicity than the same-sized COD crystals. Both apoptosis and necrosis could lead to mitochondria depolarization and elevate the expression of OPN and the generation of lipid peroxidation product MDA. The amount of expressed OPN and generated MDA was positively related to cell injury degree. The physicochemical properties of crystals could affect the cell death mode. The results of this study may provide a basis for future studies on cell death mechanisms. PMID:27551481

  10. Abrin triggers cell death by inactivating a thiol-specific antioxidant protein.

    PubMed

    Shih, S F; Wu, Y H; Hung, C H; Yang, H Y; Lin, J Y

    2001-06-15

    Abrin A-chain (ABRA) inhibits protein synthesis by its N-glycosidase activity as well as induces apoptosis, but the molecular mechanism of ABRA-induced cell death has been obscure. Using an ABRA mutant that lacks N-glycosidase activity as bait in a yeast two-hybrid system, a 30-kDa antioxidant protein-1 (AOP-1) was found to be an ABRA(E164Q)-interacting protein. The interaction was further confirmed in vitro by a glutathione S-transferase pull-down assay. The colocalization of endogenous AOP-1 and exogenous ABR proteins in the cell was demonstrated by confocal immunofluorescence. We also demonstrated that ABRA attenuates AOP-1 antioxidant activity in a dose-dependent manner and the intracellular level of reactive oxygen species (ROS) increases in ABR-treated cells. Moreover, ROS scavengers N-acetylcysteine and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl delayed programmed cell death. This indicates that ROS are important mediators of ABR-induced apoptosis. When ectopically expressed, AOP-1 blocked the release of cytochrome c and prevented apoptosis in ABR-treated cells. These findings suggest that the binding of ABRA to AOP-1 promotes apoptosis by inhibiting the mitochondrial antioxidant protein AOP-1, resulting in the increase of intracellular ROS and the release of cytochrome c from the mitochondria to the cytosol, which activates caspase-9 and caspase-3. PMID:11285261

  11. Cell birth, cell death, cell diversity and DNA breaks: how do they all fit together?

    NASA Technical Reports Server (NTRS)

    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.

  12. Programmed Cell Death in Animal Development and Disease

    PubMed Central

    Fuchs, Yaron; Steller, Hermann

    2015-01-01

    Programmed Cell Death (PCD) plays a fundamental role in animal development and tissue homeostasis. Abnormal regulation of this process is associated with a wide variety of human diseases, including immunological and developmental disorders, neuro-degeneration, and cancer. Here, we provide a brief historical overview of the field and reflect on myriad functions carried out by PCD during development and explore how PCD is regulated. We also focus on the function and regulation of apoptotic proteins, including caspases, the key executioners of apoptosis, highlighting the non-lethal functions of these proteins in diverse developmental processes including cell differentiation and tissue remodeling. Finally, we explore a growing body of work about the connections between apoptosis, stem cells and cancer, focusing on how apoptotic cells release a variety of signals to communicate with their cellular environment, including factors that promote cell division, tissue regeneration, and wound healing. PMID:22078876

  13. Thymoquinone causes multiple effects, including cell death, on dividing plant cells.

    PubMed

    Hassanien, Sameh E; Ramadan, Ahmed M; Azeiz, Ahmed Z Abdel; Mohammed, Rasha A; Hassan, Sabah M; Shokry, Ahmed M; Atef, Ahmed; Kamal, Khalid B H; Rabah, Samar; Sabir, Jamal S M; Abuzinadah, Osama A; El-Domyati, Fotouh M; Martin, Gregory B; Bahieldin, Ahmed

    2013-01-01

    Thymoquinone (TQ) is a major constituent of Nigella sativa oil with reported anti-oxidative activity and anti-inflammatory activity in animal cells. It also inhibits proliferation and induces programmed cell death (apoptosis) in human skin cancer cells. The present study sought to detect the influence of TQ on dividing cells of three plant systems and on expression of Bcl2-associated athanogene-like (BAG-like) genes that might be involved during the process of cell death. BAG genes are known for the regulation of diverse physiological processes in animals, including apoptosis, tumorigenesis, stress responses, and cell division. Synthetic TQ at 0.1mg/mL greatly reduced wheat seed germination rate, whereas 0.2mg/mL completely inhibited germination. An Evans blue assay revealed moderate cell death in the meristematic zone of Glycine max roots after 1h of TQ treatment (0.2mg/mL), with severe cell death occurring in this zone after 2h of treatment. Light microscopy of TQ-treated (0.2mg/mL) onion hairy root tips for 1h revealed anti-mitotic activity and also cell death-associated changes, including nuclear membrane disruption and nuclear fragmentation. Transmission electron microscopy of TQ-treated cells (0.2mg/mL) for 1h revealed shrinkage of the plasma membrane, leakage of cell lysate, degradation of cell walls, enlargement of vacuoles and condensation of nuclei. Expression of one BAG-like gene, previously associated with cell death, was induced 20 min after TQ treatment in Glycine max root tip cells. Thus, TQ has multiple effects, including cell death, on dividing plant cells and plants may serve as a useful system to further investigate the mechanisms underlying the response of eukaryotic cells to TQ.

  14. Cell Cycle-Dependent Mechanisms Underlie Vincristine-Induced Death of Primary Acute Lymphoblastic Leukemia Cells.

    PubMed

    Kothari, Anisha; Hittelman, Walter N; Chambers, Timothy C

    2016-06-15

    Microtubule-targeting agents (MTA), such as the taxanes and vinca alkaloids, are used to treat a variety of cancers due to their ability to perturb microtubule dynamics. In cell culture, MTAs exert their anticancer effects primarily by causing mitotic arrest and cell death. However, accumulating indirect evidence suggests that MTAs may exert their cytotoxicity in human tumors by interfering with interphase microtubules. In this study, we sought to develop and characterize an experimental system in which to test the hypothesis that MTAs induce cell death during interphase. Primary adult acute lymphoblastic leukemia (ALL) cells treated with vincristine only weakly exhibited colocalization between mitotic and apoptotic markers and major characteristics of mitotic death, such as an increase in cells with 4N DNA content before the appearance of cells with <2N DNA content, suggesting a mixed response. Therefore, we separated ALL cells into distinct phases of the cell cycle by centrifugal elutriation, labeled cells with 5-ethynyl-2'-deoxyuridine (EdU), and then treated each population with vincristine. Cells isolated during G1 underwent cell death without evidence of EdU uptake, indicating that the cytotoxic effects of vincristine took place during G1 Conversely, cells isolated during S or G2-M phases underwent death following mitotic arrest. Thus, vincristine induces distinct death programs in primary ALL cells depending on cell-cycle phase, and cells in G1 are particularly susceptible to perturbation of interphase microtubules. Primary ALL cells may therefore provide a powerful model system in which to study the multimodal mechanisms underlying MTA-induced cell death. Cancer Res; 76(12); 3553-61. ©2016 AACR. PMID:27197148

  15. Cell Cycle-Dependent Mechanisms Underlie Vincristine-Induced Death of Primary Acute Lymphoblastic Leukemia Cells.

    PubMed

    Kothari, Anisha; Hittelman, Walter N; Chambers, Timothy C

    2016-06-15

    Microtubule-targeting agents (MTA), such as the taxanes and vinca alkaloids, are used to treat a variety of cancers due to their ability to perturb microtubule dynamics. In cell culture, MTAs exert their anticancer effects primarily by causing mitotic arrest and cell death. However, accumulating indirect evidence suggests that MTAs may exert their cytotoxicity in human tumors by interfering with interphase microtubules. In this study, we sought to develop and characterize an experimental system in which to test the hypothesis that MTAs induce cell death during interphase. Primary adult acute lymphoblastic leukemia (ALL) cells treated with vincristine only weakly exhibited colocalization between mitotic and apoptotic markers and major characteristics of mitotic death, such as an increase in cells with 4N DNA content before the appearance of cells with <2N DNA content, suggesting a mixed response. Therefore, we separated ALL cells into distinct phases of the cell cycle by centrifugal elutriation, labeled cells with 5-ethynyl-2'-deoxyuridine (EdU), and then treated each population with vincristine. Cells isolated during G1 underwent cell death without evidence of EdU uptake, indicating that the cytotoxic effects of vincristine took place during G1 Conversely, cells isolated during S or G2-M phases underwent death following mitotic arrest. Thus, vincristine induces distinct death programs in primary ALL cells depending on cell-cycle phase, and cells in G1 are particularly susceptible to perturbation of interphase microtubules. Primary ALL cells may therefore provide a powerful model system in which to study the multimodal mechanisms underlying MTA-induced cell death. Cancer Res; 76(12); 3553-61. ©2016 AACR.

  16. The variability of autophagy and cell death susceptibility

    PubMed Central

    Loos, Ben; Engelbrecht, Anna-Mart; Lockshin, Richard A.; Klionsky, Daniel J; Zakeri, Zahra

    2013-01-01

    Impaired autophagic machinery is implicated in a number of diseases such as heart disease, neurodegeneration and cancer. A common denominator in these pathologies is a dysregulation of autophagy that has been linked to a change in susceptibility to cell death. Although we have progressed in understanding the molecular machinery and regulation of the autophagic pathway, many unanswered questions remain. How does the metabolic contribution of autophagy connect with the cell’s history and how does its current autophagic flux affect metabolic status and susceptibility to undergo cell death? How does autophagic flux operate to switch metabolic direction and what are the underlying mechanisms in metabolite and energetic sensing, metabolite substrate provision and metabolic integration during the cellular stress response? In this article we focus on unresolved questions that address issues around the role of autophagy in sensing the energetic environment and its role in actively generating metabolite substrates. We attempt to provide answers by explaining how and when a change in autophagic pathway activity such as primary stress response is able to affect cell viability and when not. By addressing the dynamic metabolic relationship between autophagy, apoptosis and necrosis we provide a new perspective on the parameters that connect autophagic activity, severity of injury and cellular history in a logical manner. Last, by evaluating the cell’s condition and autophagic activity in a clear context of regulatory parameters in the intra- and extracellular environment, this review provides new concepts that set autophagy into an energetic feedback loop, that may assist in our understanding of autophagy in maintaining healthy cells or when it controls the threshold between cell death and cell survival. PMID:23846383

  17. Low zinc environment induces stress signaling, senescence and mixed cell death modalities in colon cancer cells.

    PubMed

    Rudolf, Emil; Rudolf, Kamil

    2015-12-01

    Currently it is not clear what type of the final cellular response (i.e. cell death modality or senescence) is induced upon chronic intracellular zinc depletion in colon cancer cells. To address this question, isogenic colon cancer lines SW480 and SW620 exposed to low zinc environment were studied over the period of 6 weeks. Low zinc environment reduced total as well as free intracellular zinc content in both cell lines. Decreased intracellular zinc content resulted in changes in cellular proliferation, cell cycle distribution and activation of stress signaling. In addition, colonocytes with low zinc content displayed increased levels of oxidative stress, changes in mitochondrial activity but in the absence of significant DNA damage. Towards the end of treatment (4th-6th week), exposed cells started to change morphologically, and typical markers of senescence as well as cell death appeared. Of two examined colon cancer cell lines, SW480 cells proved to activate predominantly senescent phenotype, with frequent form of demise being necrosis and mixed cell death modality but not apoptosis. Conversely, SW620 cells activated mostly cell death, with relatively equal distribution of apoptosis and mixed types, while senescent phenotypes and necrosis were present only in a small fraction of cell populations. Addition of zinc at the beginning of 4th week of treatment significantly suppressed cell death phenotypes in both cell lines but had no significant effect on senescence. In conclusion, presented results demonstrate variability of responses to chronic zinc depletion in colon cancer as modeled in vitro.

  18. Involvement of ethylene and lipid signalling in cadmium-induced programmed cell death in tomato suspension cells.

    PubMed

    Yakimova, E T; Kapchina-Toteva, V M; Laarhoven, L-J; Harren, F M; Woltering, E J

    2006-10-01

    Cadmium-induced cell death was studied in suspension-cultured tomato (Lycopersicon esculentum Mill.) cells (line MsK8) treated with CdSO(4). Within 24 h, cadmium treatment induced cell death in a concentration-dependent manner. Cell cultures showed recovery after 2-3 days which indicates the existence of an adaptation mechanism. Cadmium-induced cell death was alleviated by the addition of sub muM concentrations of peptide inhibitors specific to human caspases indicating that cell death proceeds through a mechanism with similarities to animal programmed cell death (PCD, apoptosis). Cadmium-induced cell death was accompanied by an increased production of hydrogen peroxide (H(2)O(2)) and simultaneous addition of antioxidants greatly reduced cell death. Inhibitors of phospholipase C (PLC) and phospholipase D (PLD) signalling pathway intermediates reduced cadmium-induced cell death. Treatment with the G-protein activator mastoparan and a cell permeable analogue of the lipid signal second messenger phosphatidic acid (PA) induced cell death. Ethylene, while not inducing cell death when applied alone, stimulated cadmium-induced cell death. Application of the ethylene biosynthesis inhibitor aminoethoxy vinylglycine (AVG) reduced cadmium-induced cell death, and this effect was alleviated by simultaneous treatment with ethylene. Together the results show that cadmium induces PCD exhibiting apoptotic-like features. The cell death process requires increased H(2)O(2) production and activation of PLC, PLD and ethylene signalling pathways.

  19. EFFECTS OF ETHANOL AND HYDROGEN PEROXIDE ON MOUSE LIMB BUD MESENCHYME DIFFERENTIATION AND CELL DEATH

    EPA Science Inventory

    Many of the morphological defects associated with embryonic alcohol exposure are a result of cell death. During limb development, ethanol administration produces cell death in the limb and digital defects, including postaxial ectrodactyly. Because an accumulation of reactive oxyg...

  20. Cell death stages in single apoptotic and necrotic cells monitored by Raman microspectroscopy

    PubMed Central

    Brauchle, Eva; Thude, Sibylle; Brucker, Sara Y.; Schenke-Layland, Katja

    2014-01-01

    Although apoptosis and necrosis have distinct features, the identification and discrimination of apoptotic and necrotic cell death in vitro is challenging. Immunocytological and biochemical assays represent the current gold standard for monitoring cell death pathways; however, these standard assays are invasive, render large numbers of cells and impede continuous monitoring experiments. In this study, both room temperature (RT)-induced apoptosis and heat-triggered necrosis were analyzed in individual Saos-2 and SW-1353 cells by utilizing Raman microspectroscopy. A targeted analysis of defined cell death modalities, including early and late apoptosis as well as necrosis, was facilitated based on the combination of Raman spectroscopy with fluorescence microscopy. Spectral shifts were identified in the two cell lines that reflect biochemical changes specific for either RT-induced apoptosis or heat-mediated necrosis. A supervised classification model specified apoptotic and necrotic cell death based on single cell Raman spectra. To conclude, Raman spectroscopy allows a non-invasive, continuous monitoring of cell death, which may help shedding new light on complex pathophysiological or drug-induced cell death processes. PMID:24732136

  1. Molecular mechanisms of Ebola virus pathogenesis: focus on cell death

    PubMed Central

    Falasca, L; Agrati, C; Petrosillo, N; Di Caro, A; Capobianchi, M R; Ippolito, G; Piacentini, M

    2015-01-01

    Ebola virus (EBOV) belongs to the Filoviridae family and is responsible for a severe disease characterized by the sudden onset of fever and malaise accompanied by other non-specific signs and symptoms; in 30–50% of cases hemorrhagic symptoms are present. Multiorgan dysfunction occurs in severe forms with a mortality up to 90%. The EBOV first attacks macrophages and dendritic immune cells. The innate immune reaction is characterized by a cytokine storm, with secretion of numerous pro-inflammatory cytokines, which induces a huge number of contradictory signals and hurts the immune cells, as well as other tissues. Other highly pathogenic viruses also trigger cytokine storms, but Filoviruses are thought to be particularly lethal because they affect a wide array of tissues. In addition to the immune system, EBOV attacks the spleen and kidneys, where it kills cells that help the body to regulate its fluid and chemical balance and that make proteins that help the blood to clot. In addition, EBOV causes liver, lungs and kidneys to shut down their functions and the blood vessels to leak fluid into surrounding tissues. In this review, we analyze the molecular mechanisms at the basis of Ebola pathogenesis with a particular focus on the cell death pathways induced by the virus. We also discuss how the treatment of the infection can benefit from the recent experience of blocking/modulating cell death in human degenerative diseases. PMID:26024394

  2. Programmed Cell Death Initiation and Execution in Budding Yeast

    PubMed Central

    Strich, Randy

    2015-01-01

    Apoptosis or programmed cell death (PCD) was initially described in metazoans as a genetically controlled process leading to intracellular breakdown and engulfment by a neighboring cell . This process was distinguished from other forms of cell death like necrosis by maintenance of plasma membrane integrity prior to engulfment and the well-defined genetic system controlling this process. Apoptosis was originally described as a mechanism to reshape tissues during development. Given this context, the assumption was made that this process would not be found in simpler eukaryotes such as budding yeast. Although basic components of the apoptotic pathway were identified in yeast, initial observations suggested that it was devoid of prosurvival and prodeath regulatory proteins identified in mammalian cells. However, as apoptosis became extensively linked to the elimination of damaged cells, key PCD regulatory proteins were identified in yeast that play similar roles in mammals. This review highlights recent discoveries that have permitted information regarding PCD regulation in yeast to now inform experiments in animals. PMID:26272996

  3. Role of mitochondrial function in cell death and body metabolism.

    PubMed

    Lee, Myung-Shik

    2016-01-01

    Mitochondria are the key players in apoptosis and necrosis. Mitochondrial DNA (mtDNA)-depleted r0 cells were resistant to diverse apoptosis inducers such as TNF-alpha, TNFSF10, staurosporine and p53. Apoptosis resistance was accompanied by the absence of mitochondrial potential loss or cytochrome c translocation. r0 cells were also resistant to necrosis induced by reactive oxygen species (ROS) donors due to upregulation of antioxidant enzymes such as manganese superoxide dismutase. Mitochondria also has a close relationship with autophagy that plays a critical role in the turnover of senescent organelles or dysfunctional proteins and may be included in 'cell death' category. It was demonstrated that autophagy deficiency in insulin target tissues such as skeletal muscle induces mitochondrial stress response, which leads to the induction of FGF21 as a 'mitokine' and affects the whole body metabolism. These results show that mitochondria are not simply the power plants of cells generating ATP, but are closely related to several types of cell death and autophagy. Mitochondria affect various pathophysiological events related to diverse disorders such as cancer, metabolic disorders and aging. PMID:27100503

  4. Lysosomal photodamage induces cell death via mitochondrial apoptotic pathway

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Wang, Xian-wang; Li, Hui

    2009-11-01

    Lysosomal photosensitizers have been used in photodynamic therapy (PDT). Combination of such photosensitizers and light causes lysosomal photodamage, inducing cell death. The lysosomal disruption can lead to apoptosis but its signaling pathways remain to be elucidated. In this study, we selected N-aspartyl chlorin e6 (NPe6), an effective photosensitizer which preferentially accumulates in lysosomes, to study the mechanism of apoptosis caused by lysosomal photodamage. Apoptosis in living human lung adenocarcinoma cells treated by NPe6-PDT was studied using real-time single-cell analysis. In this study, the fluorescence probes Cyto c-GFP and DsRed-Mit were used to detect the spatial and temporal changes of cytochrome c in real-time in sub-cell level; the Rhodamine 123 dyes were used to monitor the changes of mitochondrial membrane potential. The results showed that, after PDT treatment,the mitochondrial membrane potential decreased, and cytochrome c released from mitochondria; The caspase-3 was activated obviously. These results suggested that lysosomal photodamage activates mitochondrial apoptotic pathway to induce cell death.

  5. The essential role of evasion from cell death in cancer

    PubMed Central

    Kelly, Gemma; Strasser, Andreas

    2011-01-01

    The link between evasion of apoptosis and the development of cellular hyperplasia and ultimately cancer is implicitly clear if one considers how many cells are produced each day and, hence, how many cells must die to make room for the new ones (reviewed in (Raff, 1996)). Furthermore, cells are frequently experiencing noxious stimuli that can cause lesions in their DNA and faults in DNA replication can occur during cellular proliferation. Such DNA damage needs to be repaired efficiently or cells with irreparable damage must be killed to prevent subsequent division of aberrant cells that may fuel tumorigenesis (reviewed in (Weinberg, 2007)). The detection of genetic lesions in human cancers that activate pro-survival genes or disable pro-apoptotic genes have provided the first evidence that defects in programmed cell death can cause cancer (Tagawa et al., 2005; Tsujimoto et al., 1984; Vaux et al., 1988) and this concept was proven by studies with genetically modified mice (Egle et al., 2004b; Strasser et al., 1990a). It is therefore now widely accepted that evasion of apoptosis is a requirement for both neoplastic transformation and sustained growth of cancer cells (reviewed in (Cory and Adams, 2002; Hanahan and Weinberg, 2000; Weinberg, 2007)). Importantly, apoptosis is also a major contributor to anti-cancer therapy induced killing of tumor cells (reviewed in (Cory and Adams, 2002; Cragg et al., 2009)). Consequently, a detailed understanding of apoptotic cell death will help to better comprehend the complexities of tumorigenesis and should assist with the development of improved targeted therapies for cancer based on the direct activation of the apoptotic machinery (reviewed in (Lessene et al., 2008)). PMID:21704830

  6. Cell Death Control by Matrix Metalloproteinases1[OPEN

    PubMed Central

    Zimmermann, Dirk; Sieferer, Elke; Pfannstiel, Jens

    2016-01-01

    In contrast to mammalian matrix metalloproteinases (MMPs) that play important roles in the remodeling of the extracellular matrix in animals, the proteases responsible for dynamic modifications of the plant cell wall are largely unknown. A possible involvement of MMPs was addressed by cloning and functional characterization of Sl2-MMP and Sl3-MMP from tomato (Solanum lycopersicum). The two tomato MMPs were found to resemble mammalian homologs with respect to gelatinolytic activity, substrate preference for hydrophobic amino acids on both sides of the scissile bond, and catalytic properties. In transgenic tomato seedlings silenced for Sl2/3-MMP expression, necrotic lesions were observed at the base of the hypocotyl. Cell death initiated in the epidermis and proceeded to include outer cortical cell layers. In later developmental stages, necrosis spread, covering the entire stem and extending into the leaves of MMP-silenced plants. The subtilisin-like protease P69B was identified as a substrate of Sl2- and Sl3-MMP. P69B was shown to colocalize with Sl-MMPs in the apoplast of the tomato hypocotyl, it exhibited increased stability in transgenic plants silenced for Sl-MMP activity, and it was cleaved and inactivated by Sl-MMPs in vitro. The induction of cell death in Sl2/3-MMP-silenced plants depended on P69B, indicating that Sl2- and Sl3-MMP act upstream of P69B in an extracellular proteolytic cascade that contributes to the regulation of cell death in tomato. PMID:27208293

  7. Autophagy Protects Against Aminochrome-Induced Cell Death in Substantia Nigra-Derived Cell Line

    PubMed Central

    Paris, Irmgard; Muñoz, Patricia; Huenchuguala, Sandro; Couve, Eduardo; Sanders, Laurie H.; Greenamyre, John Timothy; Caviedes, Pablo; Segura-Aguilar, Juan

    2011-01-01

    Aminochrome, the precursor of neuromelanin, has been proposed to be involved in the neurodegeneration neuromelanin-containing dopaminergic neurons in Parkinson’s disease. We aimed to study the mechanism of aminochrome-dependent cell death in a cell line derived from rat substantia nigra. We found that aminochrome (50μM), in the presence of NAD(P)H-quinone oxidoreductase, EC 1.6.99.2 (DT)-diaphorase inhibitor dicoumarol (DIC) (100μM), induces significant cell death (62 ± 3%; p < 0.01), increase in caspase-3 activation (p < 0.001), release of cytochrome C, disruption of mitochondrial membrane potential (p < 0.01), damage of mitochondrial DNA, damage of mitochondria determined with transmission electron microscopy, a dramatic morphological change characterized as cell shrinkage, and significant increase in number of autophagic vacuoles. To determine the role of autophagy on aminochrome-induced cell death, we incubated the cells in the presence of vinblastine and rapamycin. Interestingly, 10μM vinblastine induces a 5.9-fold (p < 0.001) and twofold (p < 0.01) significant increase in cell death when the cells were incubated with 30μM aminochrome in the absence and presence of DIC, respectively, whereas 10μM rapamycin preincubated 24 h before addition of 50μM aminochrome in the absence and the presence of 100μM DIC induces a significant decrease (p < 0.001) in cell death. In conclusion, autophagy seems to be an important protective mechanism against two different aminochrome-induced cell deaths that initially showed apoptotic features. The cell death induced by aminochrome when DT-diaphorase is inhibited requires activation of mitochondrial pathway, whereas the cell death induced by aminochrome alone requires inhibition of autophagy-dependent degrading of damaged organelles and recycling through lysosomes. PMID:21427056

  8. Adaptation to alkalosis induces cell cycle delay and apoptosis in cortical collecting duct cells: role of Aquaporin-2.

    PubMed

    Rivarola, Valeria; Flamenco, Pilar; Melamud, Luciana; Galizia, Luciano; Ford, Paula; Capurro, Claudia

    2010-08-01

    Collecting ducts (CD) not only constitute the final site for regulating urine concentration by increasing apical membrane Aquaporin-2 (AQP2) expression, but are also essential for the control of acid-base status. The aim of this work was to examine, in renal cells, the effects of chronic alkalosis on cell growth/death as well as to define whether AQP2 expression plays any role during this adaptation. Two CD cell lines were used: WT- (not expressing AQPs) and AQP2-RCCD(1) (expressing apical AQP2). Our results showed that AQP2 expression per se accelerates cell proliferation by an increase in cell cycle progression. Chronic alkalosis induced, in both cells lines, a time-dependent reduction in cell growth. Even more, cell cycle movement, assessed by 5-bromodeoxyuridine pulse-chase and propidium iodide analyses, revealed a G2/M phase cell accumulation associated with longer S- and G2/M-transit times. This G2/M arrest is paralleled with changes consistent with apoptosis. All these effects appeared 24 h before and were always more pronounced in cells expressing AQP2. Moreover, in AQP2-expressing cells, part of the observed alkalosis cell growth decrease is explained by AQP2 protein down-regulation. We conclude that in CD cells alkalosis causes a reduction in cell growth by cell cycle delay that triggers apoptosis as an adaptive reaction to this environment stress. Since cell volume changes are prerequisite for the initiation of cell proliferation or apoptosis, we propose that AQP2 expression facilitates cell swelling or shrinkage leading to the activation of channels necessary to the control of these processes. PMID:20432437

  9. Combinatorial Strategies for the Induction of Immunogenic Cell Death

    PubMed Central

    Bezu, Lucillia; Gomes-da-Silva, Ligia C.; Dewitte, Heleen; Breckpot, Karine; Fucikova, Jitka; Spisek, Radek; Galluzzi, Lorenzo; Kepp, Oliver; Kroemer, Guido

    2015-01-01

    The term “immunogenic cell death” (ICD) is commonly employed to indicate a peculiar instance of regulated cell death (RCD) that engages the adaptive arm of the immune system. The inoculation of cancer cells undergoing ICD into immunocompetent animals elicits a specific immune response associated with the establishment of immunological memory. Only a few agents are intrinsically endowed with the ability to trigger ICD. These include a few chemotherapeutics that are routinely employed in the clinic, like doxorubicin, mitoxantrone, oxaliplatin, and cyclophosphamide, as well as some agents that have not yet been approved for use in humans. Accumulating clinical data indicate that the activation of adaptive immune responses against dying cancer cells is associated with improved disease outcome in patients affected by various neoplasms. Thus, novel therapeutic regimens that trigger ICD are urgently awaited. Here, we discuss current combinatorial approaches to convert otherwise non-immunogenic instances of RCD into bona fide ICD. PMID:25964783

  10. Subnanosecond electric pulses cause membrane permeabilization and cell death.

    PubMed

    Xiao, Shu; Guo, Siqi; Nesin, Vasyl; Heller, Richard; Schoenbach, Karl H

    2011-05-01

    Subnanosecond electric pulses (200 ps) at electric field intensities on the order of 20 kV/cm cause the death of B16.F10 murine melanoma cells when applied for minutes with a pulse repetition rate of 10 kHz. The lethal effect of the ultrashort pulses is found to be caused by a combination of thermal effects and electrical effects. Studies on the cellular level show increased transport across the membrane at much lower exposure times or number of pulses. Exposed to 2000 pulses, NG108 cells exhibit an increase in membrane conductance, but only allow transmembrane currents to flow, if the medium is positively biased with respect to the cell interior. This means that the cell membrane behaves like a rectifying diode. This increase in membrane conductance is a nonthermal process, since the temperature rise due to the pulsing is negligible.

  11. Ceramide metabolism regulates autophagy and apoptotic cell death induced by melatonin in liver cancer cells.

    PubMed

    Ordoñez, Raquel; Fernández, Anna; Prieto-Domínguez, Néstor; Martínez, Laura; García-Ruiz, Carmen; Fernández-Checa, José C; Mauriz, José L; González-Gallego, Javier

    2015-09-01

    Autophagy is a process that maintains homeostasis during stress, although it also contributes to cell death under specific contexts. Ceramides have emerged as important effectors in the regulation of autophagy, mediating the crosstalk with apoptosis. Melatonin induces apoptosis of cancer cells; however, its role in autophagy and ceramide metabolism has yet to be clearly elucidated. This study was aimed to evaluate the effect of melatonin administration on autophagy and ceramide metabolism and its possible link with melatonin-induced apoptotic cell death in hepatocarcinoma (HCC) cells. Melatonin (2 mm) transiently induced autophagy in HepG2 cells through JNK phosphorylation, characterized by increased Beclin-1 expression, p62 degradation, and LC3II and LAMP-2 colocalization, which translated in decreased cell viability. Moreover, ATG5 silencing sensitized HepG2 cells to melatonin-induced apoptosis, suggesting a dual role of autophagy in cell death. Melatonin enhanced ceramide levels through both de novo synthesis and acid sphingomyelinase (ASMase) stimulation. Serine palmitoyltransferase (SPT) inhibition with myriocin prevented melatonin-induced autophagy and ASMase inhibition with imipramine-impaired autophagy flux. However, ASMase inhibition partially protected HepG2 cells against melatonin, while SPT inhibition significantly enhanced cell death. Findings suggest a crosstalk between SPT-mediated ceramide generation and autophagy in protecting against melatonin, while specific ASMase-induced ceramide production participates in melatonin-mediated cell death. Thus, dual blocking of SPT and autophagy emerges as a potential strategy to potentiate the apoptotic effects of melatonin in liver cancer cells.

  12. Statins and Voriconazole Induce Programmed Cell Death in Acanthamoeba castellanii

    PubMed Central

    López-Arencibia, Atteneri; Sifaoui, Ines; Reyes-Batlle, María; Valladares, Basilio; Martínez-Carretero, Enrique; Piñero, José E.; Maciver, Sutherland K.; Lorenzo-Morales, Jacob

    2015-01-01

    Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a life-threatening encephalitis. In order to treat those infections properly, it is necessary to target the treatment not only to the trophozoite but also to the cyst. Furthermore, it may be advantageous to avoid parasite killing by necrosis, which may induce local inflammation. We must also avoid toxicity of host tissue. Many drugs which target eukaryotes are known to induce programmed cell death (PCD), but this process is poorly characterized in Acanthamoeba. Here, we study the processes of programmed cell death in Acanthamoeba, induced by several drugs, such as statins and voriconazole. We tested atorvastatin, fluvastatin, simvastatin, and voriconazole at the 50% inhibitory concentrations (IC50s) and IC90s that we have previously established. In order to evaluate this phenomenon, we investigated the DNA fragmentation, one of the main characteristics of PCD, with quantitative and qualitative techniques. Also, the changes related to phosphatidylserine exposure on the external cell membrane and cell permeability were studied. Finally, because caspases are key to PCD pathways, caspase activity was evaluated in Acanthamoeba. All the drugs assayed in this study induced PCD in Acanthamoeba. To the best of our knowledge, this is the first study where PCD induced by drugs is described quantitatively and qualitatively in Acanthamoeba. PMID:25733513

  13. Programmed cell death in C. elegans, mammals and plants.

    PubMed

    Lord, Christina E N; Gunawardena, Arunika H L A N

    2012-08-01

    Programmed cell death (PCD) is the regulated removal of cells within an organism and plays a fundamental role in growth and development in nearly all eukaryotes. In animals, the model organism Caenorhabditis elegans (C. elegans) has aided in elucidating many of the pathways involved in the cell death process. Various analogous PCD processes can also be found within mammalian PCD systems, including vertebrate limb development. Plants and animals also appear to share hallmarks of PCD, both on the cellular and molecular level. Cellular events visualized during plant PCD resemble those seen in animals including: nuclear condensation, DNA fragmentation, cytoplasmic condensation, and plasma membrane shrinkage. Recently the molecular mechanisms involved in plant PCD have begun to be elucidated. Although few regulatory proteins have been identified as conserved across all eukaryotes, molecular features such as the participation of caspase-like proteases, Bcl-2-like family members and mitochondrial proteins appear to be conserved between plant and animal systems. Transgenic expression of mammalian and C. elegans pro- and anti-apoptotic genes in plants has been observed to dramatically influence the regulatory pathways of plant PCD. Although these genes often show little to no sequence similarity they can frequently act as functional substitutes for one another, thus suggesting that action may be more important than sequence resemblance. Here we present a summary of these findings, focusing on the similarities, between mammals, C. elegans, and plants. An emphasis will be placed on the mitochondria and its role in the cell death pathway within each organism. Through the comparison of these systems on both a cellular and molecular level we can begin to better understand PCD in plant systems, and perhaps shed light on the pathways, which are controlling the process. This manuscript adds to the field of PCD in plant systems by profiling apoptotic factors, to scale on a protein

  14. Bifurcate effects of glucose on caspase-independent cell death during hypoxia

    SciTech Connect

    Aki, Toshihiko; Nara, Akina; Funakoshi, Takeshi; Uemura, Koichi

    2010-06-04

    We investigated the effect of glucose on hypoxic death of rat cardiomyocyte-derived H9c2 cells and found that there is an optimal glucose concentration for protection against hypoxic cell death. Hypoxic cell death in the absence of glucose is accompanied by rapid ATP depletion, release of apoptosis-inducing factor from mitochondria, and nuclear chromatin condensation, all of which are inhibited by glucose in a dose-dependent manner. In contrast, excessive glucose also induces hypoxic cell death that is not accompanied by these events, suggesting a change in the mode of cell death between hypoxic cells with and without glucose supplementation.

  15. Delayed Effects of Whole Brain Radiotherapy in Germ Cell Tumor Patients With Central Nervous System Metastases

    SciTech Connect

    Doyle, Danielle M. Einhorn, Lawrence H.

    2008-04-01

    Purpose: Central nervous system (CNS) metastases are uncommon in patients with germ cell tumors, with an incidence of 2-3%. CNS metastases have been managed with whole brain radiotherapy (WBRT) and concomitant cisplatin-based combination chemotherapy. Our previous study did not observe serious CNS toxicity (Int J Radiat Oncol Biol Phys 1991;22:17-22). We now report on 5 patients who developed delayed significant CNS toxicity. Patients and Methods: We observed 5 patients with delayed CNS toxicity. The initial diagnosis was between 1981 and 2003. All patients had poor-risk disease according to the International Germ Cell Consensus Collaborative Group criteria. Of the 5 patients, 3 had CNS metastases at diagnosis and 2 developed relapses with CNS metastases. These 5 patients underwent WBRT to 4,000-5,000 cGy in 18-28 fractions concurrently with cisplatin-based chemotherapy. Results: All 5 patients developed delayed symptoms consistent with progressive multifocal leukoencephalopathy. The symptoms included seizures, hemiparesis, cranial neuropathy, headaches, blindness, dementia, and ataxia. The median time from WBRT to CNS symptoms was 72 months (range, 9-228). Head imaging revealed multiple abnormalities consistent with gliosis and diffuse cerebral atrophy. Of the 5 patients, 3 had progressive and 2 stable symptoms. Treatment with surgery and/or steroids had modest benefit. The progressive multifocal leukoencephalopathy resulted in significant debility in all 5 patients, resulting in death (3 patients), loss of work, steroid-induced morbidity, and recurrent hospitalizations. Conclusion: Whole brain radiotherapy is not innocuous in young patients with germ cell tumors and can cause late CNS toxicity.

  16. Mitochondrial Dysfunction Induced by Nuclear Poly(ADP-Ribose) Polymerase-1: a Treatable Cause of Cell Death in Stroke

    PubMed Central

    Baxter, Paul; Chen, Yanting; Xu, Yun; Swanson, Raymond A.

    2014-01-01

    Many drugs targeting excitotoxic cell death have demonstrated robust neuroprotective effects in animal models of cerebral ischemia. However, these neuroprotective effects have almost universally required drug administration at relatively short time intervals after ischemia onset. This finding has translated to clinical trial results; interventions targeting excitotoxicity have had no demonstrable efficacy when initiated hours after ischemia onset, but beneficial effects have been reported with more rapid initiation. Consequently, there continues to be a need for interventions with efficacy at later time points after ischemia. Here, we focus on mitochondrial dysfunction as both a relatively late event in ischemic neuronal death and a recognized cause of delayed neuronal death. Activation of poly(ADP-ribose) polymerase-1 (PARP-1) is a primary cause of mitochondrial depolarization and subsequent mitochondria-triggered cell death in ischemia reperfusion. PARP-1 consumes cytosolic NAD+, thereby blocking both glycolytic ATP production and delivery of glucose carbon to mitochondria for oxidative metabolism. However, ketone bodies such as pyruvate, beta- and gamma-hydroxybutyrate, and 1,4-butanediol can fuel mitochondrial metabolism in cells with depleted cytosolic NAD+ as long as the mitochondria remain functional. Ketone bodies have repeatedly been shown to be highly effective in preventing cell death in animal models of ischemia, but a rigorous study of the time window of opportunity for this approach remains to be performed. PMID:24323707

  17. Reduction of cardiac cell death after helium postconditioning in rats: transcriptional analysis of cell death and survival pathways.

    PubMed

    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.

  18. Reduction of Cardiac Cell Death after Helium Postconditioning in Rats: Transcriptional Analysis of Cell Death and Survival Pathways

    PubMed Central

    Oei, Gezina TML; 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

    2014-01-01

    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. PMID:25171109

  19. Hydralazine rescues PC12 cells from acrolein-mediated death.

    PubMed

    Liu-Snyder, Peishan; Borgens, Richard Ben; Shi, Riyi

    2006-07-01

    Acrolein, a major lipid peroxidation product, has been associated with both CNS trauma and neurodegenerative diseases. Because of its long half-life, acrolein is a potent endogenous toxin capable of killing healthy cells during the secondary injury process. Traditionally, attempts to intervene in the process of progressive cell death after the primary injury have included scavenging reactive oxygen species (so-called free radicals). The animal data supporting such an approach have generally been positive, but all human clinical trials attempting a similar outcome in human CNS injury have failed. New drugs that might reduce toxicity by scavenging the products of lipid peroxidation present a promising, and little investigated, therapeutic approach. Hydralazine, a well-known treatment for hypertension, has been reported to react with acrolein, forming hydrazone in cell-free systems. In the companion paper, we have established an acrolein-mediated cell injury model using PC12 cells in vitro. Here we test the hypothesis that the formation of hydrazone adducts with acrolein is able to reduce acrolein toxicity and spare a significant percentage of the population of PC12 cells from death. Concentrations of approximately 1 mM of this aldehyde scavenger can rescue over 80% of the population of PC12 cells. This study provides a basis for a new pharmacological treatment to reduce the effects of secondary injury in the damaged and/or diseased nervous system. In particular, we describe the need for new drugs that possess aldehyde scavenging properties but do not interfere with the regulation of blood pressure.

  20. Apoptotic tubular cell death during acute renal allograft rejection.

    PubMed

    Wever, P C; Aten, J; Rentenaar, R J; Hack, C E; Koopman, G; Weening, J J; ten Berge, I J

    1998-01-01

    Tubular cells are important targets during acute renal allograft rejection and induction of apoptosis might be a mechanism of tubular cell destruction. Susceptibility to induction of apoptosis is regulated by the homologous Bcl-2 and Bax proteins. Expression of Bcl-2 and Bax is regulated by p53, which down-regulates expression of Bcl-2, while simultaneously up-regulating expression of Bax. We studied apoptotic tubular cell death in 10 renal allograft biopsies from transplant recipients with acute rejection by in situ end-labelling and the DNA-binding fluorochrome propidium iodide. Tubular expression of p53, Bcl-2 and Bax was studies by immunohistochemistry. Five renal allograft biopsies from transplant recipients with uncomplicated clinical course and histologically normal renal tissue present in nephrectomy specimens from 4 patients with renal adenocarcinoma served as control specimens. Apoptotic cells and apoptotic bodies were detected in tubular epithelia and tubular lumina in 9 out of 10 acute rejection biopsies. In control renal tissue, apoptotic cells were detected in 1 biopsy only. Compared to control renal tissue, acute renal allograft rejection was, furthermore, associated with a shift in the ratio of Bcl-2 to Bax in favour of Bax in tubular epithelia and increased expression of p53 in tubular nuclei. These observations demonstrate that apoptosis contributes in part to tubular cell destruction during acute renal allograft rejection. In accordance, the shift in the ratio of Bcl-2 to Bax in favour of Bax indicates increased susceptibility of tubular epithelia to induction of apoptosis. The expression of p53 in tubular nuclei during acute renal allograft rejection indicates the presence of damaged DNA, which can be important in initiation of part of the observed apoptosis. These findings elucidate part of the mechanisms controlling apoptotic tubular cell death during acute renal allograft rejection.

  1. Retinal Ganglion Cell Loss is Delayed Following Optic Nerve Crush in NLRP3 Knockout Mice

    PubMed Central

    Puyang, Zhen; Feng, Liang; Chen, Hui; Liang, Peiji; Troy, John B.; Liu, Xiaorong

    2016-01-01

    The NLRP3 inflammasome, a sensor for a variety of pathogen- and host-derived threats, consists of the adaptor ASC (Apoptosis-associated Speck-like protein containing a Caspase Activation and Recruitment Domain (CARD)), pro-caspase-1, and NLRP3 (NOD-Like Receptor family Pyrin domain containing 3). NLRP3-induced neuroinflammation is implicated in the pathogenesis and progression of eye diseases, but it remains unclear whether activation of NLRP3 inflammasome contributes to retinal ganglion cell (RGC) death. Here we examined NLRP3-induced neuroinflammation and RGC survival following partial optic nerve crush (pONC) injury. We showed that NLRP3 was up-regulated in retinal microglial cells following pONC, propagating from the injury site to the optic nerve head and finally the entire retina within one day. Activation of NLRP3-ASC inflammasome led to the up-regulation of caspase-1 and a proinflammatory cytokine, interleukin-1β (IL-1β). In NLRP3 knockout mice, up-regulation of ASC, caspase-1, and IL-1β were all reduced, and, importantly, RGC and axon loss was substantially delayed following pONC injury. The average survival time of RGCs in NLRP3 knockout mice was about one week longer than for control animals. Taken together, our study demonstrated that ablating the NLRP3 gene significantly reduced neuroinflammation and delayed RGC loss after optic nerve crush injury. PMID:26893104

  2. Effect of formaldehyde on cell proliferation and death.

    PubMed

    Szende, Béla; Tyihák, Erno

    2010-12-01

    Formaldehyde (HCHO) may reach living organisms as an exogenous agent or produced within cells. The so-called formaldehydogenic compounds like S-adenosyl-L-methionine, N-hydroxymethyl-L-arginine, 1'-methyl ascorbigen, methanol, E-N-trimethyl lysine and methylamine are special exogenous sources of HCHO. Endogenous HCHO can be formed from hydroxymethyl groups during enzymatic methylation and demethylation processes. HCHO, as a highly reactive compound, is considered to be involved in the induction of apoptosis, consequently in the pathogenesis of atherosclerosis and neurodegenerative processes. The biological action of HCHO is dose-dependent. In vitro studies on tumour cell and endothelial cell cultures showed that HCHO in the concentration of 10.0 mM caused necrotic cell death, 1.0 mM resulted in enhanced apoptosis and reduced mitotic activity, while 0.5 and 0.1 mM enhanced cell proliferation and reduced apoptotic activity. Among formaldehydogenic compounds N-hydroxymethyl-L-arginine, 1'-methyl ascorbigen and the HCHO donor resveratrol may be considered as potential inhibitors of cell proliferation. Endogenous HCHO in plants apparently play a role in regulation of apoptosis and cell proliferation. The genotoxic and carcinogentic effects of HCHO is due to production of DNA-protein cross-links. Low doses of HCHO, reducing apoptotic activity may also accumulate cells with such cross-links. Experimental data point to the possible therapeutic use of methylated lysine residues and methylated arginine residues in the case of neoplasms.

  3. Peruvoside, a Cardiac Glycoside, Induces Primitive Myeloid Leukemia Cell Death.

    PubMed

    Feng, Qian; Leong, Wa Seng; Liu, Liang; Chan, Wai-In

    2016-01-01

    Despite the available chemotherapy and treatment, leukemia remains a difficult disease to cure due to frequent relapses after treatment. Among the heterogeneous leukemic cells, a rare population referred as the leukemic stem cell (LSC), is thought to be responsible for relapses and drug resistance. Cardiac glycosides (CGs) have been used in treating heart failure despite its toxicity. Recently, increasing evidence has demonstrated its new usage as a potential anti-cancer drug. Ouabain, one of the CGs, specifically targeted CD34⁺CD38(-) leukemic stem-like cells, but not the more mature CD34⁺CD38⁺ leukemic cells, making this type of compounds a potential treatment for leukemia. In search of other potential anti-leukemia CGs, we found that Peruvoside, a less studied CG, is more effective than Ouabain and Digitoxin at inducing cell death in primitive myeloid leukemia cells without obvious cytotoxicity on normal blood cells. Similar to Ouabain and Digitoxin, Peruvoside also caused cell cycle arrest at G₂/M stage. It up-regulates CDKN1A expression and activated the cleavage of Caspase 3, 8 and PARP, resulting in apoptosis. Thus, Peruvoside showed potent anti-leukemia effect, which may serve as a new anti-leukemia agent in the future. PMID:27110755

  4. Cell Arrest and Cell Death in Mammalian Preimplantation Development: Lessons from the Bovine Model

    PubMed Central

    Leidenfrost, Sandra; Boelhauve, Marc; Reichenbach, Myriam; Güngör, Tuna; Reichenbach, Horst-Dieter; Sinowatz, Fred; Wolf, Eckhard; Habermann, Felix A.

    2011-01-01

    Background The causes, modes, biological role and prospective significance of cell death in preimplantation development in humans and other mammals are still poorly understood. Early bovine embryos represent a very attractive experimental model for the investigation of this fundamental and important issue. Methods and Findings To obtain reference data on the temporal and spatial occurrence of cell death in early bovine embryogenesis, three-dimensionally preserved embryos of different ages and stages of development up to hatched blastocysts were examined in toto by confocal laser scanning microscopy. In parallel, transcript abundance profiles for selected apoptosis-related genes were analyzed by real-time reverse transcriptase-polymerase chain reaction. Our study documents that in vitro as well as in vivo, the first four cleavage cycles are prone to a high failure rate including different types of permanent cell cycle arrest and subsequent non-apoptotic blastomere death. In vitro produced and in vivo derived blastocysts showed a significant incidence of cell death in the inner cell mass (ICM), but only in part with morphological features of apoptosis. Importantly, transcripts for CASP3, CASP9, CASP8 and FAS/FASLG were not detectable or found at very low abundances. Conclusions In vitro and in vivo, errors and failures of the first and the next three cleavage divisions frequently cause immediate embryo death or lead to aberrant subsequent development, and are the main source of developmental heterogeneity. A substantial occurrence of cell death in the ICM even in fast developing blastocysts strongly suggests a regular developmentally controlled elimination of cells, while the nature and mechanisms of ICM cell death are unclear. Morphological findings as well as transcript levels measured for important apoptosis-related genes are in conflict with the view that classical caspase-mediated apoptosis is the major cause of cell death in early bovine development. PMID

  5. Trial Watch: Immunogenic cell death inducers for anticancer chemotherapy

    PubMed Central

    Pol, Jonathan; Vacchelli, Erika; Aranda, Fernando; Castoldi, Francesca; Eggermont, Alexander; Cremer, Isabelle; Sautès-Fridman, Catherine; Fucikova, Jitka; Galon, Jérôme; Spisek, Radek; Tartour, Eric; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2015-01-01

    The term “immunogenic cell death” (ICD) is now employed to indicate a functionally peculiar form of apoptosis that is sufficient for immunocompetent hosts to mount an adaptive immune response against dead cell-associated antigens. Several drugs have been ascribed with the ability to provoke ICD when employed as standalone therapeutic interventions. These include various chemotherapeutics routinely employed in the clinic (e.g., doxorubicin, epirubicin, idarubicin, mitoxantrone, bleomycin, bortezomib, cyclophosphamide and oxaliplatin) as well as some anticancer agents that are still under preclinical or clinical development (e.g., some microtubular inhibitors of the epothilone family). In addition, a few drugs are able to convert otherwise non-immunogenic instances of cell death into bona fide ICD, and may therefore be employed as chemotherapeutic adjuvants within combinatorial regimens. This is the case of cardiac glycosides, like digoxin and digitoxin, and zoledronic acid. Here, we discuss recent developments on anticancer chemotherapy based on ICD inducers. PMID:26137404

  6. Activated microglia cause reversible apoptosis of pheochromocytoma cells, inducing their cell death by phagocytosis.

    PubMed

    Hornik, Tamara C; Vilalta, Anna; Brown, Guy C

    2016-01-01

    Some apoptotic processes, such as phosphatidylserine exposure, are potentially reversible and do not necessarily lead to cell death. However, phosphatidylserine exposure can induce phagocytosis of a cell, resulting in cell death by phagocytosis: phagoptosis. Phagoptosis of neurons by microglia might contribute to neuropathology, whereas phagoptosis of tumour cells by macrophages might limit cancer. Here, we examined the mechanisms by which BV-2 microglia killed co-cultured pheochromocytoma (PC12) cells that were either undifferentiated or differentiated into neuronal cells. We found that microglia activated by lipopolysaccharide rapidly phagocytosed PC12 cells. Activated microglia caused reversible phosphatidylserine exposure on and reversible caspase activation in PC12 cells, and caspase inhibition prevented phosphatidylserine exposur and decreased subsequent phagocytosis. Nitric oxide was necessary and sufficient to induce the reversible phosphatidylserine exposure and phagocytosis. The PC12 cells were not dead at the time they were phagocytised, and inhibition of their phagocytosis left viable cells. Cell loss was inhibited by blocking phagocytosis mediated by phosphatidylserine, MFG-E8, vitronectin receptors or P2Y6 receptors. Thus, activated microglia can induce reversible apoptosis of target cells, which is insufficient to cause apoptotic cell death, but sufficient to induce their phagocytosis and therefore cell death by phagoptosis.

  7. Ras pathway signaling accelerates programmed cell death in the pathogenic fungus Candida albicans.

    PubMed

    Phillips, Andrew J; Crowe, Jonathan D; Ramsdale, Mark

    2006-01-17

    A better understanding of the molecular basis of programmed cell death (PCD) in fungi could provide information that is useful in the design of antifungal drugs that combat life-threatening fungal infections. Harsh environmental stresses, such as acetic acid or hydrogen peroxide, have been shown to induce PCD in the pathogenic fungus Candida albicans. In this study, we show that dying cells progress from an apoptotic state to a secondary necrotic state and that the rate at which this change occurs is proportional to the intensity of the stimulus. Also, we found that the temporal response is modulated by Ras-cAMP-PKA signals. Mutations that block Ras-cAMP-PKA signaling (ras1Delta, cdc35Delta, tpk1Delta, and tpk2Delta) suppress or delay the apoptotic response, whereas mutations that stimulate signaling (RAS1(val13) and pde2Delta) accelerate the rate of entry of cells into apoptosis. Pharmacological stimulation or inhibition of Ras signaling reinforces these findings. Transient increases in endogenous cAMP occur under conditions that stimulate apoptosis but not growth arrest. Death-specific changes in the abundance of different isoforms of the PKA regulatory subunit, Bcy1p, are also observed. Activation of Ras signals may regulate PCD of C. albicans, either by inhibiting antiapoptotic functions (such as stress responses) or by activating proapoptotic functions. PMID:16407097

  8. Mitochondrial dynamics and cell death in heart failure.

    PubMed

    Marín-García, José; Akhmedov, Alexander T

    2016-03-01

    The highly regulated processes of mitochondrial fusion (joining), fission (division) and trafficking, collectively called mitochondrial dynamics, determine cell-type specific morphology, intracellular distribution and activity of these critical organelles. Mitochondria are critical for cardiac function, while their structural and functional abnormalities contribute to several common cardiovascular diseases, including heart failure (HF). The tightly balanced mitochondrial fusion and fission determine number, morphology and activity of these multifunctional organelles. Although the intracellular architecture of mature cardiomyocytes greatly restricts mitochondrial dynamics, this process occurs in the adult human heart. Fusion and fission modulate multiple mitochondrial functions, ranging from energy and reactive oxygen species production to Ca(2+) homeostasis and cell death, allowing the heart to respond properly to body demands. Tightly controlled balance between fusion and fission is of utmost importance in the high energy-demanding cardiomyocytes. A shift toward fission leads to mitochondrial fragmentation, while a shift toward fusion results in the formation of enlarged mitochondria and in the fusion of damaged mitochondria with healthy organelles. Mfn1, Mfn2 and OPA1 constitute the core machinery promoting mitochondrial fusion, whereas Drp1, Fis1, Mff and MiD49/51 are the core components of fission machinery. Growing evidence suggests that fusion/fission factors in adult cardiomyocytes play essential noncanonical roles in cardiac development, Ca(2+) signaling, mitochondrial quality control and cell death. Impairment of this complex circuit causes cardiomyocyte dysfunction and death contributing to heart injury culminating in HF. Pharmacological targeting of components of this intricate network may be a novel therapeutic modality for HF treatment. PMID:26872674

  9. Comparative analysis of programmed cell death pathways in filamentous fungi

    PubMed Central

    Fedorova, Natalie D; Badger, Jonathan H; Robson, Geoff D; Wortman, Jennifer R; Nierman, William C

    2005-01-01

    Background Fungi can undergo autophagic- or apoptotic-type programmed cell death (PCD) on exposure to antifungal agents, developmental signals, and stress factors. Filamentous fungi can also exhibit a form of cell death called heterokaryon incompatibility (HI) triggered by fusion between two genetically incompatible individuals. With the availability of recently sequenced genomes of Aspergillus fumigatus and several related species, we were able to define putative components of fungi-specific death pathways and the ancestral core apoptotic machinery shared by all fungi and metazoa. Results Phylogenetic profiling of HI-associated proteins from four Aspergilli and seven other fungal species revealed lineage-specific protein families, orphan genes, and core genes conserved across all fungi and metazoa. The Aspergilli-specific domain architectures include NACHT family NTPases, which may function as key integrators of stress and nutrient availability signals. They are often found fused to putative effector domains such as Pfs, SesB/LipA, and a newly identified domain, HET-s/LopB. Many putative HI inducers and mediators are specific to filamentous fungi and not found in unicellular yeasts. In addition to their role in HI, several of them appear to be involved in regulation of cell cycle, development and sexual differentiation. Finally, the Aspergilli possess many putative downstream components of the mammalian apoptotic machinery including several proteins not found in the model yeast, Saccharomyces cerevisiae. Conclusion Our analysis identified more than 100 putative PCD associated genes in the Aspergilli, which may help expand the range of currently available treatments for aspergillosis and other invasive fungal diseases. The list includes species-specific protein families as well as conserved core components of the ancestral PCD machinery shared by fungi and metazoa. PMID:16336669

  10. Alternative flow cytometry strategies to analyze stem cells and cell death in planarians.

    PubMed

    Peiris, Tanuja Harshani; García-Ojeda, Marcos E; Oviedo, Néstor J

    2016-04-01

    Planarians possess remarkable stem cell populations that continuously support cellular turnover and are instrumental in the regeneration of tissues upon injury. Cellular turnover and tissue regeneration in planarians rely on the proper integration of local and systemic signals that regulate cell proliferation and cell death. Thus, understanding the signals controlling cellular proliferation and cell death in planarians could provide valuable insights for maintenance of adult body homeostasis and the biology of regeneration. Flow cytometry techniques have been utilized widely to identify, isolate, and characterize planarian stem cell populations. We developed alternative flow cytometry strategies that reduce the number of reagents and the time of sample preparation to analyze stem cells and cell death in planarians. The sensitivity of these methods is validated with functional studies using RNA interference and treatment with  γ irradiation or stressful conditions that are known to trigger cell death. Altogether, we provide a community resource intended to minimize adverse effects during ex vivo studies of stem cells and cell death in planarians.

  11. Alternative flow cytometry strategies to analyze stem cells and cell death in planarians

    PubMed Central

    Peiris, Tanuja Harshani; García‐Ojeda, Marcos E.

    2016-01-01

    Abstract Planarians possess remarkable stem cell populations that continuously support cellular turnover and are instrumental in the regeneration of tissues upon injury. Cellular turnover and tissue regeneration in planarians rely on the proper integration of local and systemic signals that regulate cell proliferation and cell death. Thus, understanding the signals controlling cellular proliferation and cell death in planarians could provide valuable insights for maintenance of adult body homeostasis and the biology of regeneration. Flow cytometry techniques have been utilized widely to identify, isolate, and characterize planarian stem cell populations. We developed alternative flow cytometry strategies that reduce the number of reagents and the time of sample preparation to analyze stem cells and cell death in planarians. The sensitivity of these methods is validated with functional studies using RNA interference and treatment with  γ irradiation or stressful conditions that are known to trigger cell death. Altogether, we provide a community resource intended to minimize adverse effects during ex vivo studies of stem cells and cell death in planarians. PMID:27307993

  12. Sulbutiamine counteracts trophic factor deprivation induced apoptotic cell death in transformed retinal ganglion cells.

    PubMed

    Kang, Kui Dong; Majid, Aman Shah Abdul; Kim, Kyung-A; Kang, Kyungsu; Ahn, Hong Ryul; Nho, Chu Won; Jung, Sang Hoon

    2010-11-01

    Sulbutiamine is a highly lipid soluble synthetic analogue of vitamin B(1) and is used clinically for the treatment of asthenia. The aim of our study was to demonstrate whether sulbutiamine is able to attenuate trophic factor deprivation induced cell death to transformed retinal ganglion cells (RGC-5). Cells were subjected to serum deprivation for defined periods and sulbutiamine at different concentrations was added to the cultures. Various procedures (e.g. cell viability assays, apoptosis assay, reactive oxygen species analysis, Western blot analysis, flow cytometric analysis, glutathione (GSH) and glutathione-S-transferase (GST) measurement) were used to demonstrate the effect of sulbutiamine. Sulbutiamine dose-dependently attenuated apoptotic cell death induced by serum deprivation and stimulated GSH and GST activity. Moreover, sulbutiamine decreased the expression of cleaved caspase-3 and AIF. This study demonstrates for the first time that sulbutiamine is able to attenuate trophic factor deprivation induced apoptotic cell death in neuronal cells in culture. PMID:20809085

  13. Regulation of Cell Death by IAPs and Their Antagonists.

    PubMed

    Vasudevan, Deepika; Ryoo, Hyung Don

    2015-01-01

    Inhibitors of apoptosis (IAPs) family of genes encode baculovirus IAP-repeat domain-containing proteins with antiapoptotic function. These proteins also contain RING or UBC domains and act by binding to major proapoptotic factors and ubiquitylating them. High levels of IAPs inhibit caspase-mediated apoptosis. For these cells to undergo apoptosis, IAP function must be neutralized by IAP-antagonists. Mammalian IAP knockouts do not exhibit obvious developmental phenotypes, but the cells are more sensitized to apoptosis in response to injury. Loss of the mammalian IAP-antagonist ARTS results in reduced stem cell apoptosis. In addition to the antiapoptotic properties, IAPs regulate the innate immune response, and the loss of IAP function in humans is associated with immunodeficiency. The roles of IAPs in Drosophila apoptosis regulation are more apparent, where the loss of IAP1, or the expression of IAP-antagonists in Drosophila cells, is sufficient to trigger apoptosis. In this organism, apoptosis as a fate is conferred by the transcriptional induction of the IAP-antagonists. Many signaling pathways often converge on shared enhancer regions of IAP-antagonists. Cell death sensitivity is further regulated by posttranscriptional mechanisms, including those regulated by kinases, miRs, and ubiquitin ligases. These mechanisms are employed to eliminate damaged or virus-infected cells, limit neuroblast (neural stem cell) numbers, generate neuronal diversity, and sculpt tissue morphogenesis.

  14. Cell Death and Tissue Remodeling in Planarian Regeneration

    PubMed Central

    Pellettieri, Jason; Fitzgerald, Patrick; Watanabe, Shigeki; Mancuso, Joel; Green, Douglas R.; Alvarado, Alejandro Sánchez

    2010-01-01

    Many long-lived organisms, including humans, can regenerate some adult tissues lost to physical injury or disease. Much of the previous research on mechanisms of regeneration has focused on adult stem cells, which give rise to new tissue necessary for the replacement of missing body parts. Here we report that apoptosis of differentiated cells complements stem cell division during regeneration in the planarian Schmidtea mediterranea. Specifically, we developed a whole-mount TUNEL assay that allowed us to document two dramatic increases in the rate of apoptosis following amputation – an intial localized response near the wound site and a subsequent systemic response that varies in magnitude depending on the type of fragment examined. The latter cell death response can be induced in uninjured organs, occurs in the absence of planarian stem cells, and can also be triggered by prolonged starvation. Taken together, our results implicate apoptosis in the restoration of proper anatomical scale and proportion through remodeling of existing tissues. We also report results from initial mechanistic studies of apoptosis in planarians, which revealed that a S. mediterranea homolog of the antiapoptotic gene BCL2 is required for cell survival in adult animals. We propose that apoptosis is a central mechanism working in concert with stem cell division to restore anatomical form and function during metazoan regeneration. PMID:19766622

  15. Developmental Coordination of Gamete Differentiation with Programmed Cell Death in Sporulating Yeast

    PubMed Central

    Eastwood, Michael D.

    2015-01-01

    The gametogenesis program of the budding yeast Saccharomyces cerevisiae, also known as sporulation, employs unusual internal meiotic divisions, after which all four meiotic products differentiate within the parental cell. We showed previously that sporulation is typically accompanied by the destruction of discarded immature meiotic products through their exposure to proteases released from the mother cell vacuole, which undergoes an apparent programmed rupture. Here we demonstrate that vacuolar rupture contributes to de facto programmed cell death (PCD) of the meiotic mother cell itself. Meiotic mother cell PCD is accompanied by an accumulation of depolarized mitochondria, organelle swelling, altered plasma membrane characteristics, and cytoplasmic clearance. To ensure that the gametes survive the destructive consequences of developing within a cell that is executing PCD, we hypothesized that PCD is restrained from occurring until spores have attained a threshold degree of differentiation. Consistent with this hypothesis, gene deletions that perturb all but the most terminal postmeiotic spore developmental stages are associated with altered PCD. In these mutants, meiotic mother cells exhibit a delay in vacuolar rupture and then appear to undergo an alternative form of PCD associated with catastrophic consequences for the underdeveloped spores. Our findings reveal yeast sporulation as a context of bona fide PCD that is developmentally coordinated with gamete differentiation. PMID:26092920

  16. Isogambogenic acid induces apoptosis-independent autophagic cell death in human non-small-cell lung carcinoma cells.

    PubMed

    Yang, Jianhong; Zhou, Yongzhao; Cheng, Xia; Fan, Yi; He, Shichao; Li, Shucai; Ye, Haoyu; Xie, Caifeng; Wu, Wenshuang; Li, Chunyan; Pei, Heying; Li, Luyuan; Wei, Zhe; Peng, Aihua; Wei, Yuquan; Li, Weimin; Chen, Lijuan

    2015-01-09

    To overcome drug resistance caused by apoptosis deficiency in patients with non-small cell lung carcinoma (NSCLC), there is a need to identify other means of triggering apoptosis-independent cancer cell death. We are the first to report that isogambogenic acid (iso-GNA) can induce apoptosis-independent autophagic cell death in human NSCLC cells. Several features of the iso-GNA-treated NSCLC cells indicated that iso-GNA induced autophagic cell death. First, there was no evidence of apoptosis or cleaved caspase 3 accumulation and activation. Second, iso-GNA treatment induced the formation of autophagic vacuoles, increased LC3 conversion, caused the appearance of autophagosomes and increased the expression of autophagy-related proteins. These findings provide evidence that iso-GNA induces autophagy in NSCLC cells. Third, iso-GNA-induced cell death was inhibited by autophagic inhibitors or by selective ablation of Atg7 and Beclin 1 genes. Furthermore, the mTOR inhibitor rapamycin increased iso-GNA-induced cell death by enhancing autophagy. Finally, a xenograft model provided additional evidence that iso-GNA exhibited anticancer effect through inducing autophagy-dependent cell death in NSCLC cells. Taken together, our results demonstrated that iso-GNA exhibited an anticancer effect by inducing autophagy-dependent cell death in NSCLC cells, which may be an effective chemotherapeutic agent that can be used against NSCLC in a clinical setting.

  17. Isogambogenic acid induces apoptosis-independent autophagic cell death in human non-small-cell lung carcinoma cells

    PubMed Central

    Yang, Jianhong; Zhou, Yongzhao; Cheng, Xia; Fan, Yi; He, Shichao; Li, Shucai; Ye, Haoyu; Xie, Caifeng; Wu, Wenshuang; Li, Chunyan; Pei, Heying; Li, Luyuan; Wei, Zhe; Peng, Aihua; Wei, Yuquan; Li, Weimin; Chen, Lijuan

    2015-01-01

    To overcome drug resistance caused by apoptosis deficiency in patients with non-small cell lung carcinoma (NSCLC), there is a need to identify other means of triggering apoptosis-independent cancer cell death. We are the first to report that isogambogenic acid (iso-GNA) can induce apoptosis-independent autophagic cell death in human NSCLC cells. Several features of the iso-GNA-treated NSCLC cells indicated that iso-GNA induced autophagic cell death. First, there was no evidence of apoptosis or cleaved caspase 3 accumulation and activation. Second, iso-GNA treatment induced the formation of autophagic vacuoles, increased LC3 conversion, caused the appearance of autophagosomes and increased the expression of autophagy-related proteins. These findings provide evidence that iso-GNA induces autophagy in NSCLC cells. Third, iso-GNA-induced cell death was inhibited by autophagic inhibitors or by selective ablation of Atg7 and Beclin 1 genes. Furthermore, the mTOR inhibitor rapamycin increased iso-GNA-induced cell death by enhancing autophagy. Finally, a xenograft model provided additional evidence that iso-GNA exhibited anticancer effect through inducing autophagy-dependent cell death in NSCLC cells. Taken together, our results demonstrated that iso-GNA exhibited an anticancer effect by inducing autophagy-dependent cell death in NSCLC cells, which may be an effective chemotherapeutic agent that can be used against NSCLC in a clinical setting. PMID:25571970

  18. Atg3 Overexpression Enhances Bortezomib-Induced Cell Death in SKM-1 Cell

    PubMed Central

    Wang, Qian; Zhang, Jing; Zhu, Chen; Zhang, Lu; Xu, Xiaoping

    2016-01-01

    Background Myelodysplastic syndrome (MDS) is a group of heterogeneous hematopoietic stem cell malignancies with a high risk of transformation into acute myeloid leukemia (AML). Clonal evolutions are significantly associated with transformation to AML. According to a gene expression microarray, atg3 is downregulated in MDS patients progressing to leukemia, but less is known about the function of Atg3 in the survival and death of MSD/AML cells. Moreover, the role of autophagy as a result of bortezomib treatment is controversial. The current study was designed to investigate the function of Atg3 in SKM-1 cells and to study the effect of Atg3 on cell viability and cell death following bortezomib treatment. Methods Four leukemia cell lines (SKM-1, THP-1, NB4 and K562) and two healthy patients’ bone marrow cells were analyzed for Atg3 expression via qRT-PCR and Western blotting analysis. The role of Atg3 in SKM-1 cell survival and cell death was analyzed by CCK-8 assay, trypan blue exclusion assay, DAPI staining and Annexin V/PI dual staining with or without bortezomib treatment. Western blotting analysis was used to detect proteins in autophagic and caspase signaling pathways. Electron microscopy was used to observe ultrastructural changes after Atg3 overexpression. Results Downregulation of Atg3 expression was detected in four leukemia cell lines compared with healthy bone marrow cells. Atg3 mRNA was significantly decreased in MDS patients’ bone marrow cells. Overexpression of Atg3 in SKM-1 cells resulted in AKT-mTOR-dependent autophagy, a significant reduction in cell proliferation and increased cell death, which could be overcome by the autophagy inhibitor 3-MA. SKM-1 cells overexpressing Atg3 were hypersensitive to bortezomib treatment at different concentrations via autophagic cell death and enhanced sensitivity to apoptosis in the SKM-1 cell line. Following treatment with 3-MA, the sensitivity of Atg3-overexpressing cells to bortezomib treatment was reduced

  19. Regulation of cell death receptor S-nitrosylation and apoptotic signaling by Sorafenib in hepatoblastoma cells☆

    PubMed Central

    Rodríguez-Hernández, A.; Navarro-Villarán, E.; González, R.; Pereira, S.; Soriano-De Castro, L.B.; Sarrias-Giménez, A.; Barrera-Pulido, L.; Álamo-Martínez, J.M.; Serrablo-Requejo, A.; Blanco-Fernández, G.; Nogales-Muñoz, A.; Gila-Bohórquez, A.; Pacheco, D.; Torres-Nieto, M.A.; Serrano-Díaz-Canedo, J.; Suárez-Artacho, G.; Bernal-Bellido, C.; Marín-Gómez, L.M.; Barcena, J.A.; Gómez-Bravo, M.A.; Padilla, C.A.; Padillo, F.J.; Muntané, J.

    2015-01-01

    Nitric oxide (NO) plays a relevant role during cell death regulation in tumor cells. The overexpression of nitric oxide synthase type III (NOS-3) induces oxidative and nitrosative stress, p53 and cell death receptor expression and apoptosis in hepatoblastoma cells. S-nitrosylation of cell death receptor modulates apoptosis. Sorafenib is the unique recommended molecular-targeted drug for the treatment of patients with advanced hepatocellular carcinoma. The present study was addressed to elucidate the potential role of NO during Sorafenib-induced cell death in HepG2 cells. We determined the intra- and extracellular NO concentration, cell death receptor expression and their S-nitrosylation modifications, and apoptotic signaling in Sorafenib-treated HepG2 cells. The effect of NO donors on above parameters has also been determined. Sorafenib induced apoptosis in HepG2 cells. However, low concentration of the drug (10 nM) increased cell death receptor expression, as well as caspase-8 and -9 activation, but without activation of downstream apoptotic markers. In contrast, Sorafenib (10 µM) reduced upstream apoptotic parameters but increased caspase-3 activation and DNA fragmentation in HepG2 cells. The shift of cell death signaling pathway was associated with a reduction of S-nitrosylation of cell death receptors in Sorafenib-treated cells. The administration of NO donors increased S-nitrosylation of cell death receptors and overall induction of cell death markers in control and Sorafenib-treated cells. In conclusion, Sorafenib induced alteration of cell death receptor S-nitrosylation status which may have a relevant repercussion on cell death signaling in hepatoblastoma cells. PMID:26233703

  20. Molecular and cellular control of cell death and defense signaling in pepper.

    PubMed

    Choi, Hyong Woo; Hwang, Byung Kook

    2015-01-01

    Pepper (Capsicum annuum L.) provides a good experimental system for studying the molecular and functional genomics underlying the ability of plants to defend themselves against microbial pathogens. Cell death is a genetically programmed response that requires specific host cellular factors. Hypersensitive response (HR) is defined as rapid cell death in response to a pathogen attack. Pepper plants respond to pathogen attacks by activating genetically controlled HR- or disease-associated cell death. HR cell death, specifically in incompatible interactions between pepper and Xanthomonas campestris pv. vesicatoria, is mediated by the molecular genetics and biochemical machinery that underlie pathogen-induced cell death in plants. Gene expression profiles during the HR-like cell death response, virus-induced gene silencing and transient and transgenic overexpression approaches are used to isolate and identify HR- or disease-associated cell death genes in pepper plants. Reactive oxygen species, nitric oxide, cytosolic calcium ion and defense-related hormones such as salicylic acid, jasmonic acid, ethylene and abscisic acid are involved in the execution of pathogen-induced cell death in plants. In this review, we summarize recent molecular and cellular studies of the pepper cell death-mediated defense response, highlighting the signaling events of cell death in disease-resistant pepper plants. Comprehensive knowledge and understanding of the cellular functions of pepper cell death response genes will aid the development of novel practical approaches to enhance disease resistance in pepper, thereby helping to secure the future supply of safe and nutritious pepper plants worldwide.

  1. The mystery of underground death: cell death in roots during ontogeny and in response to environmental factors.

    PubMed

    Bagniewska-Zadworna, A; Arasimowicz-Jelonek, M

    2016-03-01

    Programmed cell death (PCD) is an essential part of the ontogeny of roots and their tolerance/resistance mechanisms, allowing adaptation and growth under adverse conditions. It occurs not only at the cellular and subcellular level, but also at the levels of tissues, organs and even whole plants. This process involves a wide spectrum of mechanisms, from signalling and the expression of specific genes to the degradation of cellular structures. The major goals of this review were to broaden current knowledge about PCD processes in roots, and to identify mechanisms associated with both developmental and stress-associated cell death in roots. Vacuolar cell death, when cell contents are removed by a combination of an autophagy-associated process and the release of hydrolases from a collapsed vacuole, is responsible for programming self-destruction. Regardless of the conditions and factors inducing PCD, its subcellular events usually include the accumulation of autophagosome-like structures, and the formation of massive lytic compartments. In some cases these are followed by the nuclear changes of chromatin condensation and DNA fragmentation. Tonoplast disruption and vacuole implosion occur very rapidly, are irreversible and constitute a definitive step toward cell death in roots. Active cell elimination plays an important role in various biological processes in the life history of plants, leading to controlled cellular death during adaptation to changing environmental conditions, and organ remodelling throughout development and senescence. PMID:26332667

  2. Citreoviridin induces ROS-dependent autophagic cell death in human liver HepG2 cells.

    PubMed

    Liu, Ya-Nan; Wang, Yue-Xia; Liu, Xiao-Fang; Jiang, Li-Ping; Yang, Guang; Sun, Xian-Ce; Geng, Cheng-Yan; Li, Qiu-Juan; Chen, Min; Yao, Xiao-Feng

    2015-03-01

    Citreoviridin (CIT) is one of toxic mycotoxins derived from fungal species in moldy cereals. Whether CIT exerts hepatotoxicity and the precise molecular mechanisms of CIT hepatotoxicity are not completely elucidated. In this study, the inhibitor of autophagosome formation, 3-methyladenine, protected the cells against CIT cytotoxicity, and the autophagy stimulator rapamycin further decreased the cell viability of CIT-treated HepG2 cells. Knockdown of Atg5 with Atg5 siRNA alleviated CIT-induced cell death. These finding suggested the hypothesis that autophagic cell death contributed to CIT-induced cytotoxicity in HepG2 cells. CIT increased the autophagosome number in HepG2 cells observed under a transmission electron microscope, and this effect was confirmed by the elevated LC3-II levels detected through Western blot. Reduction of P62 protein levels and the result of LC3 turnover assay indicated that the accumulation of autophagosomes in the CIT-treated HepG2 cells was due to increased formation rather than impaired degradation. The pretreatment of HepG2 cells with the ROS inhibitor NAC reduced autophagosome formation and reversed the CIT cytotoxicity, indicating that CIT-induced autophagic cell death was ROS-dependent. In summary, ROS-dependent autophagic cell death of HpeG2 cells described in this study may help to elucidate the underlying mechanism of CIT cytotoxicity.

  3. Mitophagy switches cell death from apoptosis to necrosis in NSCLC cells treated with oncolytic measles virus.

    PubMed

    Xia, Mao; Meng, Gang; Jiang, Aiqin; Chen, Aiping; Dahlhaus, Meike; Gonzalez, Patrick; Beltinger, Christian; Wei, Jiwu

    2014-06-15

    Although apoptotic phenomena have been observed in malignant cells infected by measles virus vaccine strain Edmonston B (MV-Edm), the precise oncolytic mechanisms are poorly defined. In this study we found that MV-Edm induced autophagy and sequestosome 1-mediated mitophagy leading to decreased cytochrome c release, which blocked the pro-apoptotic cascade in non-small cell lung cancer cells (NSCLCs). The decrease of apoptosis by mitophagy favored viral replication. Persistent viral replication sustained by autophagy ultimately resulted in necrotic cell death due to ATP depletion. Importantly, when autophagy was impaired in NSCLCs MV-Edm-induced cell death was significantly abrogated despite of increased apoptosis. Taken together, our results define a novel oncolytic mechanism by which mitophagy switches cell death from apoptosis to more efficient necrosis in NSCLCs following MV-Edm infection. This provides a foundation for future improvement of oncolytic virotherapy or antiviral therapy.

  4. 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

    PubMed Central

    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. PMID:25594039

  5. 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.

    PubMed

    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. PMID:25594039

  6. An atypical active cell death process underlies the fungicidal activity of ciclopirox olamine against the yeast Saccharomyces cerevisiae.

    PubMed

    Almeida, Bruno; Sampaio-Marques, Belém; Carvalho, Joana; Silva, Manuel T; Leão, Cecília; Rodrigues, Fernando; Ludovico, Paula

    2007-05-01

    Ciclopirox olamine (CPO), a fungicidal agent widely used in clinical practice, induced in Saccharomyces cerevisiae an active cell death (ACD) process characterized by changes in nuclear morphology and chromatin condensation associated with the appearance of a population in the sub-G(0)/G(1) cell cycle phase and an arrest delay in the G(2)/M phases. This ACD was associated neither with intracellular reactive oxygen species (ROS) signaling, as revealed by the use of different classes of ROS scavengers, nor with a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive phenotype. Furthermore, CPO-induced cell death seems to be dependent on unknown protease activity but independent of the apoptotic regulators Aif1p and Yca1p and of autophagic pathways involving Apg5p, Apg8p and Uth1p. Our results show that CPO triggers in S. cerevisiae an atypical nonapoptotic, nonautophagic ACD with as yet unknown regulators. PMID:17233764

  7. Cell death versus cell survival instructed by supramolecular cohesion of nanostructures

    PubMed Central

    Newcomb, Christina J.; Sur, Shantanu; Ortony, Julia H.; Lee, One-Sun; Matson, John B.; Boekhoven, Job; Yu, Jeong Min; Schatz, George C.; Stupp, Samuel I.

    2014-01-01

    Many naturally occurring peptides containing cationic and hydrophobic domains have evolved to interact with mammalian cell membranes and have been incorporated into materials for non-viral gene delivery, cancer therapy, or treatment of microbial infections. Their electrostatic attraction to the negatively charged cell surface and hydrophobic interactions with the membrane lipids enable intracellular delivery or cell lysis. While the effects of hydrophobicity and cationic charge of soluble molecules on the cell membrane are well known, the interactions between materials with these molecular features and cells remain poorly understood. Here we report that varying the cohesive forces within nanofibres of supramolecular materials with nearly identical cationic and hydrophobic structure instruct cell death or cell survival. Weak intermolecular bonds promote cell death through disruption of lipid membranes, while materials reinforced by hydrogen bonds support cell viability. These findings provide new strategies to design biomaterials that interact with the cell membrane. PMID:24531236

  8. A Versatile Cell Death Screening Assay Using Dye-Stained Cells and Multivariate Image Analysis

    PubMed Central

    Collins, Tony J.; Ylanko, Jarkko; Geng, Fei

    2015-01-01

    Abstract A novel dye-based method for measuring cell death in image-based screens is presented. Unlike conventional high- and medium-throughput cell death assays that measure only one form of cell death accurately, using multivariate analysis of micrographs of cells stained with the inexpensive mix, red dye nonyl acridine orange, and a nuclear stain, it was possible to quantify cell death induced by a variety of different agonists even without a positive control. Surprisingly, using a single known cytotoxic agent as a positive control for training a multivariate classifier allowed accurate quantification of cytotoxicity for mechanistically unrelated compounds enabling generation of dose–response curves. Comparison with low throughput biochemical methods suggested that cell death was accurately distinguished from cell stress induced by low concentrations of the bioactive compounds Tunicamycin and Brefeldin A. High-throughput image-based format analyses of more than 300 kinase inhibitors correctly identified 11 as cytotoxic with only 1 false positive. The simplicity and robustness of this dye-based assay makes it particularly suited to live cell screening for toxic compounds. PMID:26422066

  9. PDK2-mediated alternative splicing switches Bnip3 from cell death to cell survival.

    PubMed

    Gang, Hongying; Dhingra, Rimpy; Lin, Junjun; Hai, Yan; Aviv, Yaron; Margulets, Victoria; Hamedani, Mohammad; Thanasupawat, Thatchawan; Leygue, Etienne; Klonisch, Thomas; Davie, James R; Kirshenbaum, Lorrie A

    2015-09-28

    Herein we describe a novel survival pathway that operationally links alternative pre-mRNA splicing of the hypoxia-inducible death protein Bcl-2 19-kD interacting protein 3 (Bnip3) to the unique glycolytic phenotype in cancer cells. While a full-length Bnip3 protein (Bnip3FL) encoded by exons 1-6 was expressed as an isoform in normal cells and promoted cell death, a truncated spliced variant of Bnip3 mRNA deleted for exon 3 (Bnip3Δex3) was preferentially expressed in several human adenocarcinomas and promoted survival. Reciprocal inhibition of the Bnip3Δex3/Bnip3FL isoform ratio by inhibiting pyruvate dehydrogenase kinase isoform 2 (PDK2) in Panc-1 cells rapidly induced mitochondrial perturbations and cell death. The findings of the present study reveal a novel survival pathway that functionally couples the unique glycolytic phenotype in cancer cells to hypoxia resistance via a PDK2-dependent mechanism that switches Bnip3 from cell death to survival. Discovery of the survival Bnip3Δex3 isoform may fundamentally explain how certain cells resist Bnip3 and avert death during hypoxia.

  10. PDK2-mediated alternative splicing switches Bnip3 from cell death to cell survival

    PubMed Central

    Gang, Hongying; Dhingra, Rimpy; Lin, Junjun; Hai, Yan; Aviv, Yaron; Margulets, Victoria; Hamedani, Mohammad; Thanasupawat, Thatchawan; Leygue, Etienne; Klonisch, Thomas; Davie, James R.

    2015-01-01

    Herein we describe a novel survival pathway that operationally links alternative pre-mRNA splicing of the hypoxia-inducible death protein Bcl-2 19-kD interacting protein 3 (Bnip3) to the unique glycolytic phenotype in cancer cells. While a full-length Bnip3 protein (Bnip3FL) encoded by exons 1–6 was expressed as an isoform in normal cells and promoted cell death, a truncated spliced variant of Bnip3 mRNA deleted for exon 3 (Bnip3Δex3) was preferentially expressed in several human adenocarcinomas and promoted survival. Reciprocal inhibition of the Bnip3Δex3/Bnip3FL isoform ratio by inhibiting pyruvate dehydrogenase kinase isoform 2 (PDK2) in Panc-1 cells rapidly induced mitochondrial perturbations and cell death. The findings of the present study reveal a novel survival pathway that functionally couples the unique glycolytic phenotype in cancer cells to hypoxia resistance via a PDK2-dependent mechanism that switches Bnip3 from cell death to survival. Discovery of the survival Bnip3Δex3 isoform may fundamentally explain how certain cells resist Bnip3 and avert death during hypoxia. PMID:26416963

  11. PDK2-mediated alternative splicing switches Bnip3 from cell death to cell survival.

    PubMed

    Gang, Hongying; Dhingra, Rimpy; Lin, Junjun; Hai, Yan; Aviv, Yaron; Margulets, Victoria; Hamedani, Mohammad; Thanasupawat, Thatchawan; Leygue, Etienne; Klonisch, Thomas; Davie, James R; Kirshenbaum, Lorrie A

    2015-09-28

    Herein we describe a novel survival pathway that operationally links alternative pre-mRNA splicing of the hypoxia-inducible death protein Bcl-2 19-kD interacting protein 3 (Bnip3) to the unique glycolytic phenotype in cancer cells. While a full-length Bnip3 protein (Bnip3FL) encoded by exons 1-6 was expressed as an isoform in normal cells and promoted cell death, a truncated spliced variant of Bnip3 mRNA deleted for exon 3 (Bnip3Δex3) was preferentially expressed in several human adenocarcinomas and promoted survival. Reciprocal inhibition of the Bnip3Δex3/Bnip3FL isoform ratio by inhibiting pyruvate dehydrogenase kinase isoform 2 (PDK2) in Panc-1 cells rapidly induced mitochondrial perturbations and cell death. The findings of the present study reveal a novel survival pathway that functionally couples the unique glycolytic phenotype in cancer cells to hypoxia resistance via a PDK2-dependent mechanism that switches Bnip3 from cell death to survival. Discovery of the survival Bnip3Δex3 isoform may fundamentally explain how certain cells resist Bnip3 and avert death during hypoxia. PMID:26416963

  12. A Versatile Cell Death Screening Assay Using Dye-Stained Cells and Multivariate Image Analysis.

    PubMed

    Collins, Tony J; Ylanko, Jarkko; Geng, Fei; Andrews, David W

    2015-11-01

    A novel dye-based method for measuring cell death in image-based screens is presented. Unlike conventional high- and medium-throughput cell death assays that measure only one form of cell death accurately, using multivariate analysis of micrographs of cells stained with the inexpensive mix, red dye nonyl acridine orange, and a nuclear stain, it was possible to quantify cell death induced by a variety of different agonists even without a positive control. Surprisingly, using a single known cytotoxic agent as a positive control for training a multivariate classifier allowed accurate quantification of cytotoxicity for mechanistically unrelated compounds enabling generation of dose-response curves. Comparison with low throughput biochemical methods suggested that cell death was accurately distinguished from cell stress induced by low concentrations of the bioactive compounds Tunicamycin and Brefeldin A. High-throughput image-based format analyses of more than 300 kinase inhibitors correctly identified 11 as cytotoxic with only 1 false positive. The simplicity and robustness of this dye-based assay makes it particularly suited to live cell screening for toxic compounds.

  13. New Insights into Mitochondrial Structure during Cell Death

    PubMed Central

    Perkins, Guy; Bossy-Wetzel, Ella; Ellisman, Mark H.

    2009-01-01

    Mitochondria play a pivotal role in the cascade of events associated with cell death pathways that are involved with several forms of neurodegeneration. Recent findings show that in the Bax/Bak-dependent pathway of apoptosis, the release of cytochrome c from mitochondria is a consequence of two carefully coordinated events: opening of crista junctions triggered by OPA1 oligomer disassembly and formation of outer-membrane pores. Both steps are necessary for the complete release of proapoptotic proteins. The remodeling of mitochondrial structure accompanies this pathway, including mitochondrial fission, and cristae and crista junction alterations. Yet, there is controversy surrounding the timing of certain remodeling events and whether they are necessary early events required for the release of pro-apoptotic factors or are simply a downstream after-effect. Here, we analyze the current knowledge of mitochondrial remodeling during cell death and discuss what structural alterations occur to this organelle during neurodegeneration, focusing on the higher resolution structural correlates obtained by electron microscopy and electron tomography. PMID:19464290

  14. Photodynamic Efficiency: From Molecular Photochemistry to Cell Death.

    PubMed

    Bacellar, Isabel O L; Tsubone, Tayana M; Pavani, Christiane; Baptista, Mauricio S

    2015-08-31

    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.

  15. Photodynamic Efficiency: From Molecular Photochemistry to Cell Death

    PubMed Central

    Bacellar, Isabel O. L.; Tsubone, Tayana M.; Pavani, Christiane; Baptista, Mauricio S.

    2015-01-01

    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. PMID:26334268

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Smac mimetic and oleanolic acid synergize to induce cell death in human hepatocellular carcinoma cells.

    PubMed

    Liese, Juliane; Abhari, Behnaz Ahangarian; Fulda, Simone

    2015-08-28

    Chemotherapy resistance of hepatocellular carcinoma (HCC) is still a major unsolved problem highlighting the need to develop novel therapeutic strategies. Here, we identify a novel synergistic induction of cell death by the combination of the Smac mimetic BV6, which antagonizes Inhibitor of apoptosis (IAP) proteins, and the triterpenoid oleanolic acid (OA) in human HCC cells. Importantly, BV6 and OA also cooperate to suppress long-term clonogenic survival as well as tumor growth in a preclinical in vivo model of HCC underscoring the clinical relevance of our findings. In contrast, BV6/OA cotreatment does not exert cytotoxic effects against normal primary hepatocytes, pointing to some tumor selectivity. Mechanistic studies show that BV6/OA cotreatment leads to DNA fragmentation and caspase-3 cleavage, while supply of the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD.fmk) revealed a cell type-dependent requirement of caspases for BV6/OA-induced cell death. The receptor interacting protein (RIP)1 kinase Inhibitor Necrostatin-1 (Nec-1) or genetic knockdown of RIP1 fails to rescue BV6/OA-mediated cell death, indicating that BV6/OA cotreatment does not primarily engage necroptotic cell death. Notably, the addition of several reactive oxygen species (ROS) scavengers significantly decreases BV6/OA-triggered cell death, indicating that ROS production contributes to BV6/OA-induced cell death. In conclusion, cotreatment of Smac mimetic and OA represents a novel approach for the induction of cell death in HCC and implicates further studies.

  18. Smac mimetic and oleanolic acid synergize to induce cell death in human hepatocellular carcinoma cells.

    PubMed

    Liese, Juliane; Abhari, Behnaz Ahangarian; Fulda, Simone

    2015-08-28

    Chemotherapy resistance of hepatocellular carcinoma (HCC) is still a major unsolved problem highlighting the need to develop novel therapeutic strategies. Here, we identify a novel synergistic induction of cell death by the combination of the Smac mimetic BV6, which antagonizes Inhibitor of apoptosis (IAP) proteins, and the triterpenoid oleanolic acid (OA) in human HCC cells. Importantly, BV6 and OA also cooperate to suppress long-term clonogenic survival as well as tumor growth in a preclinical in vivo model of HCC underscoring the clinical relevance of our findings. In contrast, BV6/OA cotreatment does not exert cytotoxic effects against normal primary hepatocytes, pointing to some tumor selectivity. Mechanistic studies show that BV6/OA cotreatment leads to DNA fragmentation and caspase-3 cleavage, while supply of the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD.fmk) revealed a cell type-dependent requirement of caspases for BV6/OA-induced cell death. The receptor interacting protein (RIP)1 kinase Inhibitor Necrostatin-1 (Nec-1) or genetic knockdown of RIP1 fails to rescue BV6/OA-mediated cell death, indicating that BV6/OA cotreatment does not primarily engage necroptotic cell death. Notably, the addition of several reactive oxygen species (ROS) scavengers significantly decreases BV6/OA-triggered cell death, indicating that ROS production contributes to BV6/OA-induced cell death. In conclusion, cotreatment of Smac mimetic and OA represents a novel approach for the induction of cell death in HCC and implicates further studies. PMID:25917078

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

    PubMed Central

    Jacobs, Keith M.; Bhave, Sandeep R.; Ferraro, Daniel J.; Jaboin, Jerry J.; Hallahan, Dennis E.; Thotala, Dinesh

    2012-01-01

    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. PMID:22675363

  20. Uropathogenic Escherichia coli Epigenetically Manipulate Host Cell Death Pathways.

    PubMed

    Zhang, Zhengguo; Wang, Ming; Eisel, Florian; Tchatalbachev, Svetlin; Chakraborty, Trinad; Meinhardt, Andreas; Bhushan, Sudhanshu

    2016-04-01

    Urinary tract infections caused by uropathogenic Escherichia coli (UPEC) pathovars belong to the most frequent infections in human. It is well established that UPEC can subvert innate immune responses, but the role of UPEC in interfering with host cell death pathways is not known. Here, we show that UPEC abrogates activation of the host cell prosurvival protein kinase B signaling pathway, which results in the activation of mammalian forkhead box O (FOXO) transcription factors. Although FOXOs were localized in the nucleus and showed increased DNA-binding activity, no change in the expression levels of FOXO target genes were observed. UPEC can suppress BIM expression induced by LY249002, which results in attenuation of caspase 3 activation and blockage of apoptosis. Mechanistically, BIM expression appears to be epigenetically silenced by a decrease in histone 4 acetylation at the BIM promoter site. Taken together, these results suggest that UPEC can epigenetically silence BIM expression, a molecular switch that prevents apoptosis.

  1. Simplification of vacuole structure during plant cell death triggered by culture filtrates of Erwinia carotovora.

    PubMed

    Hirakawa, Yumi; Nomura, Toshihisa; Hasezawa, Seiichiro; Higaki, Takumi

    2015-01-01

    Vacuoles are suggested to play crucial roles in plant defense-related cell death. During programmed cell death, previous live cell imaging studies have observed vacuoles to become simpler in structure and have implicated this simplification as a prelude to the vacuole's rupture and consequent lysis of the plasma membrane. Here, we examined dynamics of the vacuole in cell cycle-synchronized tobacco BY-2 (Nicotiana tabacum L. cv. Bright Yellow 2) cells during cell death induced by application of culture filtrates of Erwinia carotovora. The filtrate induced death in about 90% of the cells by 24 h. Prior to cell death, vacuole shape simplified and endoplasmic actin filaments disassembled; however, the vacuoles did not rupture until after plasma membrane integrity was lost. Instead of facilitating rupture, the simplification of vacuole structure might play a role in the retrieval of membrane components needed for defense-related cell death.

  2. Tumor-derived death receptor 6 modulates dendritic cell development.

    PubMed

    DeRosa, David C; Ryan, Paul J; Okragly, Angela; Witcher, Derrick R; Benschop, Robert J

    2008-06-01

    Studies in murine models of cancer as well as in cancer patients have demonstrated that the immune response to cancer is often compromised. This paradigm is viewed as one of the major mechanisms of tumor escape. Many therapies focus on employing the professional antigen presenting dendritic cells (DC) as a strategy to overcome immune inhibition in cancer patients. Death receptor 6 (DR6) is an orphan member of the tumor necrosis factor receptor superfamily (TNFRSF21). It is overexpressed on many tumor cells and DR6(-/-) mice display altered immunity. We investigated whether DR6 plays a role in tumorigenesis by negatively affecting the generation of anti-tumor activity. We show that DR6 is uniquely cleaved from the cell surface of tumor cell lines by the membrane-associated matrix metalloproteinase (MMP)-14, which is often overexpressed on tumor cells and is associated with malignancy. We also demonstrate that >50% of monocytes differentiating into DC die when the extracellular domain of DR6 is present. In addition, DR6 affects the cell surface phenotype of the resulting immature DC and changes their cytokine production upon stimulation with LPS/IFN-gamma. The effects of DR6 are mostly amended when these immature DC are matured with IL-1beta/TNF-alpha, as measured by cell surface phenotype and their ability to present antigen. These results implicate MMP-14 and DR6 as a mechanism tumor cells can employ to actively escape detection by the immune system by affecting the generation of antigen presenting cells.

  3. Anti-apoptotic effect of clusterin on cisplatin-induced cell death of retinoblastoma cells.

    PubMed

    Song, Hyun Beom; Jun, Hyoung-Oh; Kim, Jin Hyoung; Yu, Young Suk; Kim, Kyu-Won; Min, Bon Hong; Kim, Jeong Hun

    2013-12-01

    Clusterin is a cytoprotective chaperone protein that is known to protect various retinal cells. It was also reported to be overexpressed in several types of malignant tumors, whose chemoresistance correlates with the expression of clusterin. Herein, we investigated the effect of clusterin on cisplatin-induced cell death of retinoblastoma cells. Firstly, evaluation of clusterin expression demonstrated that it was highly expressed in human retinoblastoma tissues and cell lines (SNUOT-Rb1 and Y79) particularly in the area between viable cells around vessels and necrotic zones in the relatively avascular area in human retinoblastoma tissues. Furthermore, the effects of cisplatin on retinoblastoma cells were evaluated. Cisplatin (1 µg/ml) significantly affected cell viability of SNUOT-Rb1 cells by inducing caspase-3-dependent apoptosis. Notably, the cell death due to cisplatin was prevented by 5 µg/ml of clusterin administered 4 h prior to cisplatin treatment by inhibiting cisplatin-induced apoptosis. Furthermore, overexpression of clusterin exerted its anti-apoptotic effect on cisplatin-induced apoptosis, and effectively prevented cisplatin-induced cell death. These data suggest that clusterin, found to be expressed in human retinoblastoma, may exert anti-apoptotic effects on cisplatin-induced apoptosis and prevent cell death. Therefore, clusterin can contribute to cisplatin resistance of retinoblastoma.

  4. Resveratrol induces cell death and inhibits human herpesvirus 8 replication in primary effusion lymphoma cells.

    PubMed

    Tang, Feng-Yi; Chen, Chang-Yu; Shyu, Huey-Wen; Hong, Shin; Chen, Hung-Ming; Chiou, Yee-Hsuan; Lin, Kuan-Hua; Chou, Miao-Chen; Wang, Lin-Yu; Wang, Yi-Fen

    2015-12-01

    Resveratrol (3,4',5-trihydroxy-trans-stilbene) has been reported to inhibit proliferation of various cancer cells. However, the effects of resveratrol on the human herpesvirus 8 (HHV8) harboring primary effusion lymphoma (PEL) cells remains unclear. The anti-proliferation effects and possible mechanisms of resveratrol in the HHV8 harboring PEL cells were examined in this study. Results showed that resveratrol induced caspase-3 activation and the formation of acidic vacuoles in the HHV8 harboring PEL cells, indicating resveratrol treatment could cause apoptosis and autophagy in PEL cells. In addition, resveratrol treatment increased ROS generation but did not lead to HHV8 reactivation. ROS scavenger (N-acetyl cysteine, NAC) could attenuate both the resveratrol induced caspase-3 activity and the formation of acidic vacuoles, but failed to attenuate resveratrol induced PEL cell death. Caspase inhibitor, autophagy inhibitors and necroptosis inhibitor could not block resveratrol induced PEL cell death. Moreover, resveratrol disrupted HHV8 latent infection, inhibited HHV8 lytic gene expression and decreased virus progeny production. Overexpression of HHV8-encoded viral FLICE inhibitory protein (vFLIP) could partially block resveratrol induced cell death in PEL cells. These data suggest that resveratrol-induced cell death in PEL cells may be mediated by disruption of HHV8 replication. Resveratrol may be a potential anti-HHV8 drug and an effective treatment for HHV8-related tumors.

  5. Anti-apoptotic effect of clusterin on cisplatin-induced cell death of retinoblastoma cells.

    PubMed

    Song, Hyun Beom; Jun, Hyoung-Oh; Kim, Jin Hyoung; Yu, Young Suk; Kim, Kyu-Won; Min, Bon Hong; Kim, Jeong Hun

    2013-12-01

    Clusterin is a cytoprotective chaperone protein that is known to protect various retinal cells. It was also reported to be overexpressed in several types of malignant tumors, whose chemoresistance correlates with the expression of clusterin. Herein, we investigated the effect of clusterin on cisplatin-induced cell death of retinoblastoma cells. Firstly, evaluation of clusterin expression demonstrated that it was highly expressed in human retinoblastoma tissues and cell lines (SNUOT-Rb1 and Y79) particularly in the area between viable cells around vessels and necrotic zones in the relatively avascular area in human retinoblastoma tissues. Furthermore, the effects of cisplatin on retinoblastoma cells were evaluated. Cisplatin (1 µg/ml) significantly affected cell viability of SNUOT-Rb1 cells by inducing caspase-3-dependent apoptosis. Notably, the cell death due to cisplatin was prevented by 5 µg/ml of clusterin administered 4 h prior to cisplatin treatment by inhibiting cisplatin-induced apoptosis. Furthermore, overexpression of clusterin exerted its anti-apoptotic effect on cisplatin-induced apoptosis, and effectively prevented cisplatin-induced cell death. These data suggest that clusterin, found to be expressed in human retinoblastoma, may exert anti-apoptotic effects on cisplatin-induced apoptosis and prevent cell death. Therefore, clusterin can contribute to cisplatin resistance of retinoblastoma. PMID:24085287

  6. Humanin Derivatives Inhibit Necrotic Cell Death in Neurons

    PubMed Central

    Cohen, Aviv; Lerner-Yardeni, Jenny; Meridor, David; Kasher, Roni; Nathan, Ilana; Parola, Abraham H

    2015-01-01

    Humanin and its derivatives are peptides known for their protective antiapoptotic effects against Alzheimer’s disease. Herein, we identify a novel function of the humanin-derivative AGA(C8R)-HNG17 (namely, protection against cellular necrosis). Necrosis is one of the main modes of cell death, which was until recently considered an unmoderated process. However, recent findings suggest the opposite. We have found that AGA(C8R)-HNG17 confers protection against necrosis in the neuronal cell lines PC-12 and NSC-34, where necrosis is induced in a glucose-free medium by either chemohypoxia or by a shift from apoptosis to necrosis. Our studies in traumatic brain injury models in mice, where necrosis is the main mode of neuronal cell death, have shown that AGA(C8R)-HNG17 has a protective effect. This result is demonstrated by a decrease in a neuronal severity score and by a reduction in brain edema, as measured by magnetic resonance imaging (MRI). An insight into the peptide’s antinecrotic mechanism was attained through measurements of cellular ATP levels in PC-12 cells under necrotic conditions, showing that the peptide mitigates a necrosis-associated decrease in ATP levels. Further, we demonstrate the peptide’s direct enhancement of the activity of ATP synthase activity, isolated from rat-liver mitochondria, suggesting that AGA(C8R)-HNG17 targets the mitochondria and regulates cellular ATP levels. Thus, AGA(C8R)-HNG17 has potential use for the development of drug therapies for necrosis-related diseases, for example, traumatic brain injury, stroke, myocardial infarction, and other conditions for which no efficient drug-based treatment is currently available. Finally, this study provides new insight into the mechanisms underlying the antinecrotic mode of action of AGA(C8R)-HNG17. PMID:26062019

  7. Humanin Derivatives Inhibit Necrotic Cell Death in Neurons.

    PubMed

    Cohen, Aviv; Lerner-Yardeni, Jenny; Meridor, David; Kasher, Roni; Nathan, Ilana; Parola, Abraham H

    2015-01-01

    Humanin and its derivatives are peptides known for their protective antiapoptotic effects against Alzheimer's disease. Herein, we identify a novel function of the humanin-derivative AGA(C8R)-HNG17 (namely, protection against cellular necrosis). Necrosis is one of the main modes of cell death, which was until recently considered an unmoderated process. However, recent findings suggest the opposite. We have found that AGA(C8R)-HNG17 confers protection against necrosis in the neuronal cell lines PC-12 and NSC-34, where necrosis is induced in a glucose-free medium by either chemohypoxia or by a shift from apoptosis to necrosis. Our studies in traumatic brain injury models in mice, where necrosis is the main mode of neuronal cell death, have shown that AGA(C8R)-HNG17 has a protective effect. This result is demonstrated by a decrease in a neuronal severity score and by a reduction in brain edema, as measured by magnetic resonance imaging (MRI). An insight into the peptide's antinecrotic mechanism was attained through measurements of cellular ATP levels in PC-12 cells under necrotic conditions, showing that the peptide mitigates a necrosis-associated decrease in ATP levels. Further, we demonstrate the peptide's direct enhancement of the activity of ATP synthase activity, isolated from rat-liver mitochondria, suggesting that AGA(C8R)-HNG17 targets the mitochondria and regulates cellular ATP levels. Thus, AGA(C8R)-HNG17 has potential use for the development of drug therapies for necrosis-related diseases, for example, traumatic brain injury, stroke, myocardial infarction, and other conditions for which no efficient drug-based treatment is currently available. Finally, this study provides new insight into the mechanisms underlying the antinecrotic mode of action of AGA(C8R)-HNG17.

  8. Humanin Derivatives Inhibit Necrotic Cell Death in Neurons.

    PubMed

    Cohen, Aviv; Lerner-Yardeni, Jenny; Meridor, David; Kasher, Roni; Nathan, Ilana; Parola, Abraham H

    2015-01-01

    Humanin and its derivatives are peptides known for their protective antiapoptotic effects against Alzheimer's disease. Herein, we identify a novel function of the humanin-derivative AGA(C8R)-HNG17 (namely, protection against cellular necrosis). Necrosis is one of the main modes of cell death, which was until recently considered an unmoderated process. However, recent findings suggest the opposite. We have found that AGA(C8R)-HNG17 confers protection against necrosis in the neuronal cell lines PC-12 and NSC-34, where necrosis is induced in a glucose-free medium by either chemohypoxia or by a shift from apoptosis to necrosis. Our studies in traumatic brain injury models in mice, where necrosis is the main mode of neuronal cell death, have shown that AGA(C8R)-HNG17 has a protective effect. This result is demonstrated by a decrease in a neuronal severity score and by a reduction in brain edema, as measured by magnetic resonance imaging (MRI). An insight into the peptide's antinecrotic mechanism was attained through measurements of cellular ATP levels in PC-12 cells under necrotic conditions, showing that the peptide mitigates a necrosis-associated decrease in ATP levels. Further, we demonstrate the peptide's direct enhancement of the activity of ATP synthase activity, isolated from rat-liver mitochondria, suggesting that AGA(C8R)-HNG17 targets the mitochondria and regulates cellular ATP levels. Thus, AGA(C8R)-HNG17 has potential use for the development of drug therapies for necrosis-related diseases, for example, traumatic brain injury, stroke, myocardial infarction, and other conditions for which no efficient drug-based treatment is currently available. Finally, this study provides new insight into the mechanisms underlying the antinecrotic mode of action of AGA(C8R)-HNG17. PMID:26062019

  9. Cell death atlas of the postnatal mouse ventral forebrain and hypothalamus: effects of age and sex.

    PubMed

    Ahern, Todd H; Krug, Stefanie; Carr, Audrey V; Murray, Elaine K; Fitzpatrick, Emmett; Bengston, Lynn; McCutcheon, Jill; De Vries, Geert J; Forger, Nancy G

    2013-08-01

    Naturally occurring cell death is essential to the development of the mammalian nervous system. Although the importance of developmental cell death has been appreciated for decades, there is no comprehensive account of cell death across brain areas in the mouse. Moreover, several regional sex differences in cell death have been described for the ventral forebrain and hypothalamus, but it is not known how widespread the phenomenon is. We used immunohistochemical detection of activated caspase-3 to identify dying cells in the brains of male and female mice from postnatal day (P) 1 to P11. Cell death density, total number of dying cells, and regional volume were determined in 16 regions of the hypothalamus and ventral forebrain (the anterior hypothalamus, arcuate nucleus, anteroventral periventricular nucleus, medial preoptic nucleus, paraventricular nucleus, suprachiasmatic nucleus, and ventromedial nucleus of the hypothalamus; the basolateral, central, and medial amygdala; the lateral and principal nuclei of the bed nuclei of the stria terminalis; the caudate-putamen; the globus pallidus; the lateral septum; and the islands of Calleja). All regions showed a significant effect of age on cell death. The timing of peak cell death varied between P1 to P7, and the average rate of cell death varied tenfold among regions. Several significant sex differences in cell death and/or regional volume were detected. These data address large gaps in the developmental literature and suggest interesting region-specific differences in the prevalence and timing of cell death in the hypothalamus and ventral forebrain.

  10. Drug insight: cancer therapy strategies based on restoration of endogenous cell death mechanisms.

    PubMed

    Reed, John C

    2006-07-01

    Cell death is a normal facet of human physiology, ensuring tissue homeostasis by offsetting cell production with cell demise. Neoplasms arise in part because of defects in physiological cell death mechanisms, contributing to pathological cell expansion. Defects in normal cell death pathways also contribute to cancer progression by permitting progressively aberrant cell behaviors, while also desensitizing tumor cells to immune-mediated attack, radiation, and chemotherapy. Through basic research, much has been learned about the molecular mechanisms responsible for cell turnover and how tumors escape cell death. By exploiting this knowledge base, several innovative strategies for eradicating malignancies have materialized that are based on restoration of natural pathways for cell autodestruction. Some of these strategies have advanced into human clinical trials. Several of the current strategies based on targeting core components of the cell death machinery for cancer therapy are reviewed here, and a summary of progress toward clinical applications is provided. PMID:16826219

  11. Functional inactivation of Rb sensitizes cancer cells to TSC2 inactivation induced cell Death

    PubMed Central

    Danos, Arpad M.; Liao, Yang; Li, Xuan; Du, Wei

    2012-01-01

    We showed previously that inactivation of TSC2 induces death in cancer cells lacking the Retinoblastoma (Rb) tumor suppressor under stress conditions, suggesting that inactivation of TSC2 can potentially be used as an approach to specifically kill cancers that have lost WT Rb. As Rb is often inactivated in cancers by overexpression of cyclin D1, loss of p16ink4a cdk inhibitor, or expression of viral oncoproteins, it will be interesting to determine if such functional inactivation of Rb would similarly sensitize cancer cells to TSC2 inactivation induced cell death. In addition, many cancers lack functional Pten, resulting in increased PI3K/Akt signaling that has been shown to modulate E2F-induced cell death. Therefore it will be interesting to test whether loss of Pten will affect TSC2 inactivation induced killing of Rb mutant cancer cells. Here, we show that overexpression of Cyclin D1 or the viral oncogene E1a sensitizes cancer cells to TSC2 knockdown induced cell death and growth inhibition. On the other hand, knockdown of p16ink4a sensitizes cancer cells to TSC2 knockdown induced cell death in a manner that is likely dependant on serum induction of Cyclin D1 to inactivate the Rb function. Additionally, we demonstrate that loss of Pten does not interfere with TSC2 knockdown induced cell death in Rb mutant cancer cells. Together, these results suggest that TSC2 is potentially a useful target for a large spectrum of cancer types with an inactivated Rb pathway. PMID:23022476

  12. Prune melanoidins protect against oxidative stress and endothelial cell death.

    PubMed

    Posadino, Anna Maria; Cossu, Annalisa; Piga, Antonio; Madrau, Monica Assunta; Del Caro, Alessandra; Colombino, Maria; Paglietti, Bianca; Rubino, Salvatore; Iaccarino, Ciro; Crosio, Claudia; Sanna, Bastiano; Pintus, Gianfranco

    2011-06-01

    The health-promoting effects of fruit and vegetable consumption are thought to be due to phytochemicals contained in fresh plant material. Whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed plums (prunes) were isolated and their presence confirmed by hydroxymethylfurfural content and browning index. Oxidative-induced endothelial cell (EC) damage is the trigger for the development of cardiovascular diseases (CVD); therefore the potential protective effect of prune melanoidins on hydrogen peroxide-induced oxidative cell damage was investigated on human endothelial ECV304 cells. Cytoplasmic and mitochondrial redox status was assessed by using the novel, redox-sensitive, ratiometric fluorescent protein sensor (roGFP), while mitochondrial membrane potential (MMP) was investigated with the fluorescent dye, JC-1. Treatment of ECV304 cells with hydrogen peroxide dose-dependently induced both mitochondrial and cytoplasmic oxidation, in addition to MMP dissipation, with ensuing cell death. Pretreatment of ECV304 with prune melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide elicited phenomena, clearly indicating that these polymers protect human EC against oxidative stress.

  13. The oncolytic peptide LTX-315 triggers immunogenic cell death

    PubMed Central

    Zhou, H; Forveille, S; Sauvat, A; Yamazaki, T; Senovilla, L; Ma, Y; Liu, P; Yang, H; Bezu, L; Müller, K; Zitvogel, L; Rekdal, Ø; Kepp, O; Kroemer, G

    2016-01-01

    LTX-315 is a cationic amphilytic peptide that preferentially permeabilizes mitochondrial membranes, thereby causing partially BAX/BAK1-regulated, caspase-independent necrosis. Based on the observation that intratumorally injected LTX-315 stimulates a strong T lymphocyte-mediated anticancer immune response, we investigated whether LTX-315 may elicit the hallmarks of immunogenic cell death (ICD), namely (i) exposure of calreticulin on the plasma membrane surface, (ii) release of ATP into the extracellular space, (iii) exodus of HMGB1 from the nucleus, and (iv) induction of a type-1 interferon response. Using a panel of biosensor cell lines and robotized fluorescence microscopy coupled to automatic image analysis, we observed that LTX-315 induces all known ICD characteristics. This conclusion was validated by several independent methods including immunofluorescence stainings (for calreticulin), bioluminescence assays (for ATP), immunoassays (for HMGB1), and RT-PCRs (for type-1 interferon induction). When injected into established cancers, LTX-315 caused a transiently hemorrhagic focal necrosis that was accompanied by massive release of HMGB1 (from close-to-all cancer cells), as well as caspase-3 activation in a fraction of the cells. LTX-315 was at least as efficient as the positive control, the anthracycline mitoxantrone (MTX), in inducing local inflammation with infiltration by myeloid cells and T lymphocytes. Collectively, these results support the idea that LTX-315 can induce ICD, hence explaining its capacity to mediate immune-dependent therapeutic effects. PMID:26962684

  14. Programmed cell death in plants: A chloroplastic connection

    PubMed Central

    Ambastha, Vivek; Tripathy, Baishnab C; Tiwari, Budhi Sagar

    2015-01-01

    Programmed cell death (PCD) is an integral cellular program by which targeted cells culminate to demise under certain developmental and pathological conditions. It is essential for controlling cell number, removing unwanted diseased or damaged cells and maintaining the cellular homeostasis. The details of PCD process has been very well elucidated and characterized in animals but similar understanding of the process in plants has not been achieved rather the field is still in its infancy that sees some sporadic reports every now and then. The plants have 2 energy generating sub-cellular organelles- mitochondria and chloroplasts unlike animals that just have mitochondria. The presence of chloroplast as an additional energy transducing and ROS generating compartment in a plant cell inclines to advocate the involvement of chloroplasts in PCD execution process. As chloroplasts are supposed to be progenies of unicellular photosynthetic organisms that evolved as a result of endosymbiosis, the possibility of retaining some of the components involved in bacterial PCD by chloroplasts cannot be ruled out. Despite several excellent reviews on PCD in plants, there is a void on an update of information at a place on the regulation of PCD by chloroplast. This review has been written to provide an update on the information supporting the involvement of chloroplast in PCD process and the possible future course of the field. PMID:25760871

  15. Chloroquine-induced autophagic vacuole accumulation and cell death in glioma cells is p53 independent.

    PubMed

    Geng, Ying; Kohli, Latika; Klocke, Barbara J; Roth, Kevin A

    2010-05-01

    Glioblastoma (GBM) is a high-grade central nervous system malignancy and despite aggressive treatment strategies, GBM patients have a median survival time of just 1 year. Chloroquine (CQ), an antimalarial lysosomotropic agent, has been identified as a potential adjuvant in the treatment regimen of GBMs. However, the mechanism of CQ-induced tumor cell death is poorly defined. We and others have shown that CQ-mediated cell death may be p53-dependent and at least in part due to the intrinsic apoptotic death pathway. Here, we investigated the effects of CQ on 5 established human GBM lines, differing in their p53 gene status. CQ was found to induce a concentration-dependent death in each of these cell lines. Although CQ treatment increased caspase-3-like enzymatic activity in all 5 cell lines, a broad-spectrum caspase inhibitor did not significantly attenuate death. Moreover, CQ caused an accumulation of autophagic vacuoles in all cell lines and was found to affect the levels and subcellular distribution of cathepsin D, suggesting that altered lysosomal function may also play a role in CQ-induced cell death. Thus, CQ can induce p53-independent death in gliomas that do not require caspase-mediated apoptosis. To potentially identify more potent chemotherapeutics, various CQ derivatives and lysosomotropic compounds were tested on the GBM cells. Quinacrine and mefloquine were found to be more potent than CQ in killing GBM cells in vitro and given their superior blood-brain barrier penetration compared with CQ may prove more efficacious as chemotherapeutic agents for GBM patients.

  16. Cyclosporin A inhibits programmed cell death and cytochrome c release induced by fusicoccin in sycamore cells.

    PubMed

    Contran, N; Cerana, R; Crosti, P; Malerba, M

    2007-01-01

    Programmed cell death plays a vital role in normal plant development, response to environmental stresses, and defense against pathogen attack. Different types of programmed cell death occur in plants and the involvement of mitochondria is still under investigation. In sycamore (Acer pseudoplatanus L.) cultured cells, the phytotoxin fusicoccin induces cell death that shows apoptotic features, including chromatin condensation, DNA fragmentation, and release of cytochrome c from mitochondria. In this work, we show that cyclosporin A, an inhibitor of the permeability transition pore of animal mitochondria, inhibits the cell death, DNA fragmentation, and cytochrome c release induced by fusicoccin. In addition, we show that fusicoccin induces a change in the shape of mitochondria which is not prevented by cyclosporin A. These results suggest that the release of cytochrome c induced by fusicoccin occurs through a cyclosporin A-sensitive system that is similar to the permeability transition pore of animal mitochondria and they make it tempting to speculate that this release may be involved in the phytotoxin-induced programmed cell death of sycamore cells.

  17. Photodynamic therapy-induced programmed cell death in carcinoma cell lines

    NASA Astrophysics Data System (ADS)

    He, Xiao-Yan; Sikes, Robert A.; Thomsen, Sharon L.; Chung, L.; Jacques, Steven L.

    1993-06-01

    The mode of cell death following photodynamic therapy (PDT) was investigated from the perspective of programmed cell death (apoptosis). Human prostate carcinoma cells (PC3), human non-small cell lung carcinoma (H322a), and rat mammary carcinoma (MTF7) were treated by PDT following sensitization with dihematoporphyrin ether (DHE). The response of these carcinoma cell lines to PDT was variable. An examination of extracted cellular DNA by gel electrophoresis showed the characteristic DNA ladder pattern indicative of internucleosomal cleavage of DNA during apoptosis. MTF7 and PC3 responded to PDT by inducing apoptosis while H322a had no apoptotic response. The magnitude of the response and the PDT dosage required to induce the effect were different in PC3 and MTF7. MTF7 cells responded with rapid apoptosis at the dose of light and drug that yielded 50% cell death (LD50). In contrast, PC3 showed only marginal apoptosis at the LD50 but had a marked response at the LD85. Furthermore, the onset of apoptosis followed slower kinetics in PC3 (2 hr - 4 hr) than in MTF7 (< 1 hr). H322a cells were killed by PDT but failed to exhibit any apoptotic response. This study indicates that apoptosis may occur during PDT induced cell death, but this pathway is not universal for all cancer cell lines.

  18. Immune cell populations in cutaneous delayed-type hypersensitivity

    PubMed Central

    1983-01-01

    Delayed-type hypersensitivity (DTH) is a prototypic T lymphocyte- mediated response to antigenic challenge. In this study, mononuclear cells infiltrating the skin during cutaneous response to tuberculin in presensitized human subjects (responders) and nonimmune controls were identified using monoclonal antibodies by indirect immunofluorescence. In both responders and controls the infiltrate consisted mainly of T lymphocytes (T11+ and OKT3+) and monocytes (OKM1+, 63D3+, Mo2+) which initially accumulated in proximity to small blood vessels and later infiltrated the interstitial dermis and epidermis. More T lymphocytes reacted with OKT4 than with OKT8. 6 h after tuberculin the ratio of OKT4/OKT8 in tissue from responders exceeded that in blood, whereas in tissues studied at 15-48 h and in all control tissues those ratios in blood and tissue were similar. Evidence of T lymphocyte activation was sought using monoclonal antibodies anti-Tac, OKT9, and OKT10. In responders but not in controls the proportion of infiltrating cells reactive with these antibodies increased during the course of DTH. The presence of activated T lymphocytes in tissue was not associated with a comparable increase in peripheral blood cell populations identified by anti-Tac and OKT10. Studies using anti-B1, Leu-7, and anti-IgD/IgM revealed comparatively few reactive cells. Dual-labeling studies demonstrated that most Leu-7--reactive cells also bound T11 while fewer bound OKM1 or OKT8 and that cells reactive with OKIa1 and T11 constituted largely nonoverlapping populations. Specific patterns of reactivity were not observed when tissues were stained with anti-human C3, or poly C9-MA, a monoclonal antibody reactive with a neoantigen on polymerized C9 of the membrane attack complex of complement. The number of epidermal Langerhans cells identified by OKT6 was similar in responders and controls. Thus, the cutaneous response to tuberculin in sensitized individuals is characterized by early enrichment of

  19. Sex stratified neuronal cultures to study ischemic cell death pathways.

    PubMed

    Fairbanks, Stacy L; Vest, Rebekah; Verma, Saurabh; Traystman, Richard J; Herson, Paco S

    2013-01-01

    Sex differences in neuronal susceptibility to ischemic injury and neurodegenerative disease have long been observed, but the signaling mechanisms responsible for those differences remain unclear. Primary disassociated embryonic neuronal culture provides a simplified experimental model with which to investigate the neuronal cell signaling involved in cell death as a result of ischemia or disease; however, most neuronal cultures used in research today are mixed sex. Researchers can and do test the effects of sex steroid treatment in mixed sex neuronal cultures in models of neuronal injury and disease, but accumulating evidence suggests that the female brain responds to androgens, estrogens, and progesterone differently than the male brain. Furthermore, neonate male and female rodents respond differently to ischemic injury, with males experiencing greater injury following cerebral ischemia than females. Thus, mixed sex neuronal cultures might obscure and confound the experimental results; important information might be missed. For this reason, the Herson Lab at the University of Colorado School of Medicine routinely prepares sex-stratified primary disassociated embryonic neuronal cultures from both hippocampus and cortex. Embryos are sexed before harvesting of brain tissue and male and female tissue are disassociated separately, plated separately, and maintained separately. Using this method, the Herson Lab has demonstrated a male-specific role for the ion channel TRPM2 in ischemic cell death. In this manuscript, we share and discuss our protocol for sexing embryonic mice and preparing sex-stratified hippocampal primary disassociated neuron cultures. This method can be adapted to prepare sex-stratified cortical cultures and the method for embryo sexing can be used in conjunction with other protocols for any study in which sex is thought to be an important determinant of outcome. PMID:24378980

  20. Phagocytosis genes nonautonomously promote developmental cell death in the Drosophila ovary

    PubMed Central

    Timmons, Allison K.; Mondragon, Albert A.; Schenkel, Claire E.; Yalonetskaya, Alla; Taylor, Jeffrey D.; Moynihan, Katherine E.; Etchegaray, Jon Iker; Meehan, Tracy L.; McCall, Kimberly

    2016-01-01

    Programmed cell death (PCD) is usually considered a cell-autonomous suicide program, synonymous with apoptosis. Recent research has revealed that PCD is complex, with at least a dozen cell death modalities. Here, we demonstrate that the large-scale nonapoptotic developmental PCD in the Drosophila ovary occurs by an alternative cell death program where the surrounding follicle cells nonautonomously promote death of the germ line. The phagocytic machinery of the follicle cells, including Draper, cell death abnormality (Ced)-12, and c-Jun N-terminal kinase (JNK), is essential for the death and removal of germ-line–derived nurse cells during late oogenesis. Cell death events including acidification, nuclear envelope permeabilization, and DNA fragmentation of the nurse cells are impaired when phagocytosis is inhibited. Moreover, elimination of a small subset of follicle cells prevents nurse cell death and cytoplasmic dumping. Developmental PCD in the Drosophila ovary is an intriguing example of nonapoptotic, nonautonomous PCD, providing insight on the diversity of cell death mechanisms. PMID:26884181

  1. Phagocytosis genes nonautonomously promote developmental cell death in the Drosophila ovary.

    PubMed

    Timmons, Allison K; Mondragon, Albert A; Schenkel, Claire E; Yalonetskaya, Alla; Taylor, Jeffrey D; Moynihan, Katherine E; Etchegaray, Jon Iker; Meehan, Tracy L; McCall, Kimberly

    2016-03-01

    Programmed cell death (PCD) is usually considered a cell-autonomous suicide program, synonymous with apoptosis. Recent research has revealed that PCD is complex, with at least a dozen cell death modalities. Here, we demonstrate that the large-scale nonapoptotic developmental PCD in the Drosophila ovary occurs by an alternative cell death program where the surrounding follicle cells nonautonomously promote death of the germ line. The phagocytic machinery of the follicle cells, including Draper, cell death abnormality (Ced)-12, and c-Jun N-terminal kinase (JNK), is essential for the death and removal of germ-line-derived nurse cells during late oogenesis. Cell death events including acidification, nuclear envelope permeabilization, and DNA fragmentation of the nurse cells are impaired when phagocytosis is inhibited. Moreover, elimination of a small subset of follicle cells prevents nurse cell death and cytoplasmic dumping. Developmental PCD in the Drosophila ovary is an intriguing example of nonapoptotic, nonautonomous PCD, providing insight on the diversity of cell death mechanisms. PMID:26884181

  2. Phagocytosis genes nonautonomously promote developmental cell death in the Drosophila ovary.

    PubMed

    Timmons, Allison K; Mondragon, Albert A; Schenkel, Claire E; Yalonetskaya, Alla; Taylor, Jeffrey D; Moynihan, Katherine E; Etchegaray, Jon Iker; Meehan, Tracy L; McCall, Kimberly

    2016-03-01

    Programmed cell death (PCD) is usually considered a cell-autonomous suicide program, synonymous with apoptosis. Recent research has revealed that PCD is complex, with at least a dozen cell death modalities. Here, we demonstrate that the large-scale nonapoptotic developmental PCD in the Drosophila ovary occurs by an alternative cell death program where the surrounding follicle cells nonautonomously promote death of the germ line. The phagocytic machinery of the follicle cells, including Draper, cell death abnormality (Ced)-12, and c-Jun N-terminal kinase (JNK), is essential for the death and removal of germ-line-derived nurse cells during late oogenesis. Cell death events including acidification, nuclear envelope permeabilization, and DNA fragmentation of the nurse cells are impaired when phagocytosis is inhibited. Moreover, elimination of a small subset of follicle cells prevents nurse cell death and cytoplasmic dumping. Developmental PCD in the Drosophila ovary is an intriguing example of nonapoptotic, nonautonomous PCD, providing insight on the diversity of cell death mechanisms.

  3. Consensus guidelines for the detection of immunogenic cell death

    PubMed Central

    Kepp, Oliver; Senovilla, Laura; Vitale, Ilio; Vacchelli, Erika; Adjemian, Sandy; Agostinis, Patrizia; Apetoh, Lionel; Aranda, Fernando; Barnaba, Vincenzo; Bloy, Norma; Bracci, Laura; Breckpot, Karine; Brough, David; Buqué, Aitziber; Castro, Maria G.; Cirone, Mara; Colombo, Maria I.; Cremer, Isabelle; Demaria, Sandra; Dini, Luciana; Eliopoulos, Aristides G.; Faggioni, Alberto; Formenti, Silvia C.; Fučíková, Jitka; Gabriele, Lucia; Gaipl, Udo S.; Galon, Jérôme; Garg, Abhishek; Ghiringhelli, François; Giese, Nathalia A.; Guo, Zong Sheng; Hemminki, Akseli; Herrmann, Martin; Hodge, James W.; Holdenrieder, Stefan; Honeychurch, Jamie; Hu, Hong-Min; Huang, Xing; Illidge, Tim M.; Kono, Koji; Korbelik, Mladen; Krysko, Dmitri V.; Loi, Sherene; Lowenstein, Pedro R.; Lugli, Enrico; Ma, Yuting; Madeo, Frank; Manfredi, Angelo A.; Martins, Isabelle; Mavilio, Domenico; Menger, Laurie; Merendino, Nicolò; Michaud, Michael; Mignot, Gregoire; Mossman, Karen L.; Multhoff, Gabriele; Oehler, Rudolf; Palombo, Fabio; Panaretakis, Theocharis; Pol, Jonathan; Proietti, Enrico; Ricci, Jean-Ehrland; Riganti, Chiara; Rovere-Querini, Patrizia; Rubartelli, Anna; Sistigu, Antonella; Smyth, Mark J.; Sonnemann, Juergen; Spisek, Radek; Stagg, John; Sukkurwala, Abdul Qader; Tartour, Eric; Thorburn, Andrew; Thorne, Stephen H.; Vandenabeele, Peter; Velotti, Francesca; Workenhe, Samuel T.; Yang, Haining; Zong, Wei-Xing; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    Apoptotic cells have long been considered as intrinsically tolerogenic or unable to elicit immune responses specific for dead cell-associated antigens. However, multiple stimuli can trigger a functionally peculiar type of apoptotic demise that does not go unnoticed by the adaptive arm of the immune system, which we named “immunogenic cell death” (ICD). ICD is preceded or accompanied by the emission of a series of immunostimulatory damage-associated molecular patterns (DAMPs) in a precise spatiotemporal configuration. Several anticancer agents that have been successfully employed in the clinic for decades, including various chemotherapeutics and radiotherapy, can elicit ICD. Moreover, defects in the components that underlie the capacity of the immune system to perceive cell death as immunogenic negatively influence disease outcome among cancer patients treated with ICD inducers. Thus, ICD has profound clinical and therapeutic implications. Unfortunately, the gold-standard approach to detect ICD relies on vaccination experiments involving immunocompetent murine models and syngeneic cancer cells, an approach that is incompatible with large screening campaigns. Here, we outline strategies conceived to detect surrogate markers of ICD in vitro and to screen large chemical libraries for putative ICD inducers, based on a high-content, high-throughput platform that we recently developed. Such a platform allows for the detection of multiple DAMPs, like cell surface-exposed calreticulin, extracellular ATP and high mobility group box 1 (HMGB1), and/or the processes that underlie their emission, such as endoplasmic reticulum stress, autophagy and necrotic plasma membrane permeabilization. We surmise that this technology will facilitate the development of next-generation anticancer regimens, which kill malignant cells and simultaneously convert them into a cancer-specific therapeutic vaccine. PMID:25941621

  4. Baicalein induces programmed cell death in Candida albicans.

    PubMed

    Dai, Bao-Di; Cao, Ying-Ying; Huang, Shan; Xu, Yong-Gang; Gao, Ping-Hui; Wang, Yan; Jiang, Yuan-Ying

    2009-08-01

    Recent evidence has revealed the occurrence of an apoptotic phenotype in Candida albicans that is inducible with environmental stresses such as acetic acid, hydrogen peroxide, and amphotericin B. In the present study, we found that the Chinese herbal medicine Baicalein (BE), which was one of the skullcapflavones, can induce apoptosis in C. albicans. The apoptotic effects of BE were detected by flow cytometry using Annexin V-FITC and DAPI, and it was confirmed by transmission electron microscopy analysis. After exposure to 4 microg/ml BE for 12 h, about 10% of C. albicans cells were apoptotic. Both the increasing intracellular levels of reactive oxygen species (ROS) and upregulation of some redox-related genes (CAP1, SOD2, TRR1) were observed. Furthermore, we compared the survivals of CAP1 deleted, wild-type, and overexpressed strains and found that Cap1p attenuated BE-initiated cell death, which was coherent with a higher mRNA level of the CAP1 gene. In addition, the mitochondrial membrane potential of C. albicans cells changed significantly ( p<0.001) upon BE treatment compared with control. Taken together, our results indicate that BE treatment induces apoptosis in C.albicans cells, and the apoptosis was associated with the breakdown of mitochondrial membrane potential. PMID:19734718

  5. Nonapoptotic cell death in acute kidney injury and transplantation.

    PubMed

    Linkermann, Andreas

    2016-01-01

    Acute tubular necrosis causes a loss of renal function, which clinically presents as acute kidney failure (AKI). The biochemical signaling pathways that trigger necrosis have been investigated in detail over the past 5 years. It is now clear that necrosis (regulated necrosis, RN) represents a genetically driven process that contributes to the pathophysiology of AKI. RN pathways such as necroptosis, ferroptosis, parthanatos, and mitochondrial permeability transition-induced regulated necrosis (MPT-RN) may be mechanistically distinct, and the relative contributions to overall organ damage during AKI in living organisms largely remain elusive. In a synchronized manner, some necrotic programs induce the breakdown of tubular segments and multicellular functional units, whereas others are limited to killing single cells in the tubular compartment. Importantly, the means by which a renal cell dies may have implications for the subsequent inflammatory response. In this review, the recent advances in the field of renal cell death in AKI and key enzymes that might serve as novel therapeutic targets will be discussed. As a consequence of the interference with RN, the immunogenicity of dying cells in AKI in renal transplants will be diminished, rendering inhibitors of RN indirect immunosuppressive agents. PMID:26759047

  6. TORC1 is required to balance cell proliferation and cell death in planarians.

    PubMed

    Tu, Kimberly C; Pearson, Bret J; Sánchez Alvarado, Alejandro

    2012-05-15

    Multicellular organisms are equipped with cellular mechanisms that enable them to replace differentiated cells lost to normal physiological turnover, injury, and for some such as planarians, even amputation. This process of tissue homeostasis is generally mediated by adult stem cells (ASCs), tissue-specific stem cells responsible for maintaining anatomical form and function. To do so, ASCs must modulate the balance between cell proliferation, i.e. in response to nutrients, and that of cell death, i.e. in response to starvation or injury. But how these two antagonistic processes are coordinated remains unclear. Here, we explore the role of the core components of the TOR pathway during planarian tissue homeostasis and regeneration and identified an essential function for TORC1 in these two processes. RNAi-mediated silencing of TOR in intact animals resulted in a significant increase in cell death, whereas stem cell proliferation and stem cell maintenance were unaffected. Amputated animals failed to increase stem cell proliferation after wounding and displayed defects in tissue remodeling. Together, our findings suggest two distinct roles for TORC1 in planarians. TORC1 is required to modulate the balance between cell proliferation and cell death during normal cell turnover and in response to nutrients. In addition, it is required to initiate appropriate stem cell proliferation during regeneration and for proper tissue remodeling to occur to maintain scale and proportion.

  7. How does ethanol induce apoptotic cell death of SK-N-SH neuroblastoma cells.

    PubMed

    Moon, Yong; Kwon, Yongil; Yu, Shun

    2013-07-15

    A body of evidence suggests that ethanol can lead to damage of neuronal cells. However, the mechanism underlying the ethanol-induced damage of neuronal cells remains unclear. The role of mitogen-activated protein kinases in ethanol-induced damage was investigated in SK-N-SH neuroblastoma cells. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide cell viability assay, DNA fragmentation detection, and flow cytometric analysis showed that ethanol induced apoptotic cell death and cell cycle arrest, characterized by increased caspase-3 activity, DNA fragmentation, nuclear disruption, and G1 arrest of cell cycle of the SK-N-SH neuroblastoma cells. In addition, western blot analysis indicated that ethanol induced a lasting increase in c-Jun N-terminal protein kinase activity and a transient increase in p38 kinase activity of the neuroblastoma cells. c-Jun N-terminal protein kinase or p38 kinase inhibitors significantly reduced the ethanol-induced cell death. Ethanol also increased p53 phosphorylation, followed by an increase in p21 tumor suppressor protein and a decrease in phospho-Rb (retinoblastoma) protein, leading to alterations in the expressions and activity of cyclin dependent protein kinases. Our results suggest that ethanol mediates apoptosis of SK-N-SH neuroblastoma cells by activating p53-related cell cycle arrest possibly through activation of the c-Jun N-terminal protein kinase-related cell death pathway. PMID:25206494

  8. TORC1 is required to balance cell proliferation and cell death in planarians

    PubMed Central

    Tu, Kimberly C.; Pearson, Bret J.; Alvarado, Alejandro Sánchez

    2012-01-01

    Multicellular organisms are equipped with cellular mechanisms that enable them to replace differentiated cells lost to normal physiological turnover, injury, and for some such as planarians, even amputation. This process of tissue homeostasis is generally mediated by adult stem cells (ASCs), tissue-specific stem cells responsible for maintaining anatomical form and function. To do so, ASCs must modulate the balance between cell proliferation, i.e. in response to nutrients, and that of cell death, i.e. in response to starvation or injury. But how these two antagonistic processes are coordinated remains unclear. Here, we explore the role of the core components of the TOR pathway during planarian tissue homeostasis and regeneration and identified an essential function for TORC1 in these two processes. RNAi-mediated silencing of TOR in intact animals resulted in a significant increase in cell death, whereas stem cell proliferation and stem cell maintenance were unaffected. Amputated animals failed to increase stem cell proliferation after wounding and displayed defects in tissue remodeling. Together, our findings suggest two distinct roles for TORC1 in planarians. TORC1 is required to modulate the balance between cell proliferation and cell death during normal cell turnover and in response to nutrients. In addition, it is required to initiate appropriate stem cell proliferation during regeneration and for proper tissue remodeling to occur to maintain scale and proportion. PMID:22445864

  9. DJ-1 Protects Pancreatic Beta Cells from Cytokine- and Streptozotocin-Mediated Cell Death.

    PubMed

    Jain, Deepak; Weber, Gesine; Eberhard, Daniel; Mehana, Amir E; Eglinger, Jan; Welters, Alena; Bartosinska, Barbara; Jeruschke, Kay; Weiss, Jürgen; Päth, Günter; Ariga, Hiroyoshi; Seufert, Jochen; Lammert, Eckhard

    2015-01-01

    A hallmark feature of type 1 and type 2 diabetes mellitus is the progressive dysfunction and loss of insulin-producing pancreatic beta cells, and inflammatory cytokines are known to trigger beta cell death. Here we asked whether the anti-oxidant protein DJ-1 encoded by the Parkinson's disease gene PARK7 protects islet cells from cytokine- and streptozotocin-mediated cell death. Wild type and DJ-1 knockout mice (KO) were treated with multiple low doses of streptozotocin (MLDS) to induce inflammatory beta cell stress and cell death. Subsequently, glucose tolerance tests were performed, and plasma insulin as well as fasting and random blood glucose concentrations were monitored. Mitochondrial morphology and number of insulin granules were quantified in beta cells. Moreover, islet cell damage was determined in vitro after streptozotocin and cytokine treatment of isolated wild type and DJ-1 KO islets using calcein AM/ethidium homodimer-1 staining and TUNEL staining. Compared to wild type mice, DJ-1 KO mice became diabetic following MLDS treatment. Insulin concentrations were substantially reduced, and fasting blood glucose concentrations were significantly higher in MLDS-treated DJ-1 KO mice compared to equally treated wild type mice. Rates of beta cell apoptosis upon MLDS treatment were twofold higher in DJ-1 KO mice compared to wild type mice, and in vitro inflammatory cytokines led to twice as much beta cell death in pancreatic islets from DJ-1 KO mice versus those of wild type mice. In conclusion, this study identified the anti-oxidant protein DJ-1 as being capable of protecting pancreatic islet cells from cell death induced by an inflammatory and cytotoxic setting. PMID:26422139

  10. Ceramide metabolism regulates autophagy and apoptotic-cell death induced by melatonin in liver cancer cells

    PubMed Central

    Ordoñez, Raquel; Fernández, Ana; Prieto-Domínguez, Néstor; Martínez, Laura; García-Ruiz, Carmen; Fernández-Checa, José C.; Mauriz, José L.; González-Gallego, Javier

    2015-01-01

    Autophagy is a process that maintains homeostasis during stress, although it also contributes to cell death under specific contexts. Ceramides have emerged as important effectors in the regulation of autophagy, mediating the crosstalk with apoptosis. Melatonin induces apoptosis of cancer cells; however, its role in autophagy and ceramide metabolism has yet to be clearly elucidated. This study was aimed to evaluate the effect of melatonin administration on autophagy and ceramide metabolism and its possible link with melatonin-induced apoptotic cell death in hepatocarcinoma (HCC) cells. Melatonin (2 mM) transiently induced autophagy in HepG2 cells through JNK phosphorylation, characterized by increased Beclin1 expression, p62 degradation and LC3II and LAMP2 colocalization, which translated in decreased cell viability. Moreover, ATG5-silencing sensitized HepG2 cells to melatonin induced-apoptosis, suggesting a dual role of autophagy in cell death. Melatonin enhanced ceramide levels through both de novo synthesis and acid sphingomyelinase (ASMase) stimulation. Serine palmitoyl transferase (SPT) inhibition with myriocin prevented melatonin induced autophagy and ASMase inhibition with imipramine impaired autophagy flux. However, ASMase inhibition partially protected HepG2 cells against melatonin while SPT inhibition significantly enhanced cell death. Findings suggest a cross-talk between SPT-mediated ceramide generation and autophagy in protecting against melatonin, while specific ASMase-induced ceramide production participates in melatonin-mediated cell death. Thus, dual blocking of SPT and autophagy emerge as a potential strategy to potentiate the apoptotic effects of melatonin in liver cancer cells. PMID:25975536

  11. Cell-Centric View of Apoptosis and Apoptotic Cell Death-Inducing Antitumoral Strategies

    PubMed Central

    Apraiz, Aintzane; Boyano, Maria Dolores; Asumendi, Aintzane

    2011-01-01

    Programmed cell death and especially apoptotic cell death, occurs under physiological conditions and is also desirable under pathological circumstances. However, the more we learn about cellular signaling cascades, the less plausible it becomes to find restricted and well-limited signaling pathways. In this context, an extensive description of pathway-connections is necessary in order to point out the main regulatory molecules as well as to select the most appropriate therapeutic targets. On the other hand, irregularities in programmed cell death pathways often lead to tumor development and cancer-related mortality is projected to continue increasing despite the effort to develop more active and selective antitumoral compounds. In fact, tumor cell plasticity represents a major challenge in chemotherapy and improvement on anticancer therapies seems to rely on appropriate drug combinations. An overview of the current status regarding apoptotic pathways as well as available chemotherapeutic compounds provides a new perspective of possible future anticancer strategies. PMID:24212653

  12. Calcium signaling as a mediator of cell energy demand and a trigger to cell death.

    PubMed

    Bhosale, Gauri; Sharpe, Jenny A; Sundier, Stephanie Y; Duchen, Michael R

    2015-09-01

    Calcium signaling is pivotal to a host of physiological pathways. A rise in calcium concentration almost invariably signals an increased cellular energy demand. Consistent with this, calcium signals mediate a number of pathways that together serve to balance energy supply and demand. In pathological states, calcium signals can precipitate mitochondrial injury and cell death, especially when coupled to energy depletion and oxidative or nitrosative stress. This review explores the mechanisms that couple cell signaling pathways to metabolic regulation or to cell death. The significance of these pathways is exemplified by pathological case studies, such as those showing loss of mitochondrial calcium uptake 1 in patients and ischemia/reperfusion injury.

  13. Calcium signaling as a mediator of cell energy demand and a trigger to cell death

    PubMed Central

    Bhosale, Gauri; Sharpe, Jenny A.; Sundier, Stephanie Y.

    2015-01-01

    Calcium signaling is pivotal to a host of physiological pathways. A rise in calcium concentration almost invariably signals an increased cellular energy demand. Consistent with this, calcium signals mediate a number of pathways that together serve to balance energy supply and demand. In pathological states, calcium signals can precipitate mitochondrial injury and cell death, especially when coupled to energy depletion and oxidative or nitrosative stress. This review explores the mechanisms that couple cell signaling pathways to metabolic regulation or to cell death. The significance of these pathways is exemplified by pathological case studies, such as those showing loss of mitochondrial calcium uptake 1 in patients and ischemia/reperfusion injury. PMID:26375864

  14. NFκB inhibitors induce cell death in glioblastomas.

    PubMed

    Zanotto-Filho, Alfeu; Braganhol, Elizandra; Schröder, Rafael; de Souza, Luís Henrique T; Dalmolin, Rodrigo J S; Pasquali, Matheus A Bittencourt; Gelain, Daniel Pens; Battastini, Ana Maria Oliveira; Moreira, José Cláudio Fonseca

    2011-02-01

    Identification of novel target pathways in glioblastoma (GBM) remains critical due to poor prognosis, inefficient therapies and recurrence associated with these tumors. In this work, we evaluated the role of nuclear-factor-kappa-B (NFκB) in the growth of GBM cells, and the potential of NFκB inhibitors as antiglioma agents. NFκB pathway was found overstimulated in GBM cell lines and in tumor specimens compared to normal astrocytes and healthy brain tissues, respectively. Treatment of a panel of established GBM cell lines (U138MG, U87, U373 and C6) with pharmacological NFκB inhibitors (BAY117082, parthenolide, MG132, curcumin and arsenic trioxide) and NFκB-p65 siRNA markedly decreased the viability of GBMs as compared to inhibitors of other signaling pathways such as MAPKs (ERK, JNK and p38), PKC, EGFR and PI3K/Akt. In addition, NFκB inhibitors presented a low toxicity to normal astrocytes, indicating selectivity to cancerous cells. In GBMs, mitochondrial dysfunction (membrane depolarization, bcl-xL downregulation and cytochrome c release) and arrest in the G2/M phase were observed at the early steps of NFκB inhibitors treatment. These events preceded sub-G1 detection, apoptotic body formation and caspase-3 activation. Also, NFκB was found overstimulated in cisplatin-resistant C6 cells, and treatment of GBMs with NFκB inhibitors overcame cisplatin resistance besides potentiating the effects of the chemotherapeutics, cisplatin and doxorubicin. These findings support NFκB as a potential target to cell death induction in GBMs, and that the NFκB inhibitors may be considered for in vivo testing on animal models and possibly on GBM therapy.

  15. Licensed to Kill: Mitochondria, Chloroplasts, and Cell Death.

    PubMed

    Van Aken, Olivier; Van Breusegem, Frank

    2015-11-01

    Programmed cell death (PCD) is crucial in plant organogenesis and survival. In this review the involvement of mitochondria and chloroplasts in PCD execution is critically assessed. Recent findings support a central role for mitochondria in PCD, with newly identified components of the mitochondrial electron transport chain (mETC), FOF1 ATP synthase, cardiolipins, and ATPase AtOM66. While chloroplasts received less attention, their contribution to PCD is well supported, suggesting that they possibly contribute by producing reactive oxygen species (ROS) in the presence of light or even contribute through cytochrome f release. Finally we discuss two working models where mitochondria and chloroplasts could cooperatively execute PCD: mitochondria initiate the commitment steps and recruit chloroplasts for swift execution or, alternatively, mitochondria and chloroplasts could operate in parallel.

  16. Autophagy in Dictyostelium: genes and pathways, cell death and infection.

    PubMed

    Calvo-Garrido, Javier; Carilla-Latorre, Sergio; Kubohara, Yuzuru; Santos-Rodrigo, Natalia; Mesquita, Ana; Soldati, Thierry; Golstein, Pierre; Escalante, Ricardo

    2010-08-01

    The use of simple organisms to understand the molecular and cellular function of complex processes is instrumental for the rapid development of biomedical research. A remarkable example has been the discovery in S. cerevisiae of a group of proteins involved in the pathways of autophagy. Orthologues of these proteins have been identified in humans and experimental model organisms. Interestingly, some mammalian autophagy proteins do not seem to have homologues in yeast but are present in Dictyostelium, a social amoeba with two distinctive life phases, a unicellular stage in nutrient-rich conditions that differentiates upon starvation into a multicellular stage that depends on autophagy. This review focuses on the identification and annotation of the putative Dictyostelium autophagy genes and on the role of autophagy in development, cell death and infection by bacterial pathogens. PMID:20603609

  17. OXIDATIVE STRESS INDUCES CELL DEATH IN CD-1 MOUSE CRANIAL NEURAL CREST CELLS IN VITRO

    EPA Science Inventory

    OXIDATIVE STRESS INDUCES CELL DEATH IN CD-1 MOUSE CRANIAL NEURAL CREST CELLS IN VITRO. J.B. Smith, K.K. Sulik, E.S. Hunter III. University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.
    The induction of craniofacial defects by ethanol exposure is mediated in part by...

  18. Dynamic quantitative photothermal monitoring of cell death of individual human red blood cells upon glucose depletion

    NASA Astrophysics Data System (ADS)

    Vasudevan, Srivathsan; Chen, George Chung Kit; Andika, Marta; Agarwal, Shuchi; Chen, Peng; Olivo, Malini

    2010-09-01

    Red blood cells (RBCs) have been found to undergo ``programmed cell death,'' or eryptosis, and understanding this process can provide more information about apoptosis of nucleated cells. Photothermal (PT) response, a label-free photothermal noninvasive technique, is proposed as a tool to monitor the cell death process of living human RBCs upon glucose depletion. Since the physiological status of the dying cells is highly sensitive to photothermal parameters (e.g., thermal diffusivity, absorption, etc.), we applied linear PT response to continuously monitor the death mechanism of RBC when depleted of glucose. The kinetics of the assay where the cell's PT response transforms from linear to nonlinear regime is reported. In addition, quantitative monitoring was performed by extracting the relevant photothermal parameters from the PT response. Twofold increases in thermal diffusivity and size reduction were found in the linear PT response during cell death. Our results reveal that photothermal parameters change earlier than phosphatidylserine externalization (used for fluorescent studies), allowing us to detect the initial stage of eryptosis in a quantitative manner. Hence, the proposed tool, in addition to detection of eryptosis earlier than fluorescence, could also reveal physiological status of the cells through quantitative photothermal parameter extraction.

  19. HAMLET (human alpha-lactalbumin made lethal to tumor cells) triggers autophagic tumor cell death.

    PubMed

    Aits, Sonja; Gustafsson, Lotta; Hallgren, Oskar; Brest, Patrick; Gustafsson, Mattias; Trulsson, Maria; Mossberg, Ann-Kristin; Simon, Hans-Uwe; Mograbi, Baharia; Svanborg, Catharina

    2009-03-01

    HAMLET, a complex of partially unfolded alpha-lactalbumin and oleic acid, kills a wide range of tumor cells. Here we propose that HAMLET causes macroautophagy in tumor cells and that this contributes to their death. Cell death was accompanied by mitochondrial damage and a reduction in the level of active mTOR and HAMLET triggered extensive cytoplasmic vacuolization and the formation of double-membrane-enclosed vesicles typical of macroautophagy. In addition, HAMLET caused a change from uniform (LC3-I) to granular (LC3-II) staining in LC3-GFP-transfected cells reflecting LC3 translocation during macroautophagy, and this was blocked by the macroautophagy inhibitor 3-methyladenine. HAMLET also caused accumulation of LC3-II detected by Western blot when lysosomal degradation was inhibited suggesting that HAMLET caused an increase in autophagic flux. To determine if macroautophagy contributed to cell death, we used RNA interference against Beclin-1 and Atg5. Suppression of Beclin-1 and Atg5 improved the survival of HAMLET-treated tumor cells and inhibited the increase in granular LC3-GFP staining. The results show that HAMLET triggers macroautophagy in tumor cells and suggest that macroautophagy contributes to HAMLET-induced tumor cell death.

  20. Direct induction of autophagy by Atg1 inhibits cell growth and induces apoptotic cell death

    PubMed Central

    Scott, Ryan C.; Juhász, Gábor; Neufeld, Thomas P.

    2007-01-01

    Background To survive starvation and other forms of stress, eukaryotic cells undergo a lysosomal process of cytoplasmic degradation known as autophagy. Autophagy has been implicated in a number of cellular and developmental processes, including cell growth control and programmed cell death. However, direct evidence of a causal role for autophagy in these processes is lacking, due in part to the pleiotropic effects of signaling molecules such as TOR that regulate autophagy. Here, we circumvent this difficulty by directly manipulating autophagy rates in Drosophila through the autophagy-specific protein kinase Atg1. Results We find that overexpression of Atg1 is sufficient to induce high levels of autophagy, the first such demonstration among wild type Atg proteins. In contrast to findings in yeast, induction of autophagy by Atg1 is dependent on its kinase activity. We find that cells with high levels of Atg1-induced autophagy are rapidly eliminated, demonstrating that autophagy is capable of inducing cell death. However, this cell death is caspase dependent and displays DNA fragmentation, suggesting that autophagy represents an alternative induction of apoptosis, rather than a distinct form of cell death. In addition, we demonstrate that Atg1-induced autophagy strongly inhibits cell growth, and that Atg1 mutant cells have a relative growth advantage under conditions of reduced TOR signaling. Finally, we show that Atg1 expression results in negative feedback on the activity of TOR itself. Conclusions Our results reveal a central role for Atg1 in mounting a coordinated autophagic response, and demonstrate that autophagy has the capacity to induce cell death. Furthermore, this work identifies autophagy as a critical mechanism by which inhibition of TOR signaling leads to reduced cell growth. PMID:17208179

  1. Carbon monoxide and mitochondria—modulation of cell metabolism, redox response and cell death

    PubMed Central

    Almeida, Ana S.; Figueiredo-Pereira, Cláudia; Vieira, Helena L. A.

    2015-01-01

    Carbon monoxide (CO) is an endogenously produced gasotransmitter, which is associated with cytoprotection and cellular homeostasis in several distinct cell types and tissues. CO mainly targets mitochondria because: (i) mitochondrial heme-proteins are the main potential candidates for CO to bind, (ii) many CO's biological actions are dependent on mitochondrial ROS signaling and (iii) heme is generated in the mitochondrial compartment. Mitochondria are the key cell energy factory, producing ATP through oxidative phosphorylation and regulating cell metabolism. These organelles are also implicated in many cell signaling pathways and the production of reactive oxygen species (ROS). Finally, mitochondria contain several factors activating programmed cell death pathways, which are released from the mitochondrial inter-membrane space upon mitochondrial membrane permeabilization. Therefore, disclosing CO mode of action at mitochondria opens avenues for deeper understanding CO's biological properties. Herein, it is discussed how CO affects the three main aspects of mitochondrial modulation of cell function: metabolism, redox response and cell death. PMID:25709582

  2. To Be or Not to Be?: How Selective Autophagy and Cell Death Govern Cell Fate

    PubMed Central

    Green, Douglas R.; Levine, Beth

    2014-01-01

    The health of metazoan organisms requires an effective response to organellar and cellular damage – either by repair of such damage and/or by elimination of the damaged parts of the cells or the damaged cell in its entirety. Here we consider the progress that has been made in the last two decades in determining the fates of damaged organelles and damaged cells, through discrete, but genetically overlapping, pathways involving the selective autophagy and cell death machinery. We further discuss the ways in which the autophagy machinery may impact the clearance and consequences of dying cells for host physiology. Failure in the proper removal of damaged organelles and/or damaged cells by selective autophagy and cell death processes is likely to contribute to developmental abnormalities, cancer, aging, inflammation, and other diseases. PMID:24679527

  3. Type I collagen gel protects murine fibrosarcoma L929 cells from TNFα-induced cell death

    SciTech Connect

    Wang, Hong-Ju; He, Wen-Qi; Chen, Ling; Liu, Wei-Wei; Xu, Qian; Xia, Ming-Yu; Hayashi, Toshihiko; Fujisaki, Hitomi; Hattori, Shunji; Tashiro, Shin-ichi; Onodera, Satoshi; Ikejima, Takashi

    2015-02-20

    Murine fibrosarcoma L929 cells have been used to test efficacy of proinflammatory cytokine TNFα. In the present study, we reported on protective effect of type I collagen gel used as L929 cell culture. L929 cell grew and proliferated well on collagen gel. However, the L929 cells exhibited cobblestone-like morphology which was much different from the spread fusiform shape when cultured on conventional cell dishes as well as the cells tended to aggregate. On conventional cell culture dishes, the cells treated with TNFα became round in shape and eventually died in a necroptotic manner. The cells cultured on collagen gel, however, were completely unaffected. TNFα treatment was reported to induce autophagy in L929 cells on the plastic dish, and therefore we investigated the effect of collagen gel on induction of autophagy. The results indicated that autophagy induced by TNFα treatment was much reduced when the cells were cultured on collagen gel. In conclusion, type I collagen gel protected L929 cell from TNFα-induced cell death. - Highlights: • Collagen gel culture changed the morphology of L929 cells. • L929 cell cultured on collagen gel were resistant to TNFα-induced cell death. • Collagen gel culture inhibited TNFα-induced autophagy in L929 cells.

  4. Activation of caspase-8 and Erk-1/2 in domes regulates cell death induced by confluence in MDCK cells.

    PubMed

    Chang, Yung-Heng; Lin, Hsi-Hui; Wang, Yang-Kao; Chiu, Wen-Tai; Su, Hsiao-Wen; Tang, Ming-Jer

    2007-04-01

    Under normal culture conditions, cells adhere to culture dish, spread out, proliferate, and finally cover all areas and reach confluence. During the confluent stage, cell proliferation ceases and differentiation is enhanced. Meanwhile, cell death also appears as the monolayer confluence proceeds. To delineate the mechanism of cell death induced by the confluent process, we employed Madin-Darby canine kidney (MDCK) cells. When approaching confluence, MDCK cells exhibited increase the levels of caspase-2 and enhanced the activity of caspase-8. Using various caspase inhibitors to block apoptosis, we found that only z-VAD-fmk and z-IETD-fmk can inhibit confluent cell death, indicating that confluent cell death is mediated by activation of caspase-8. Overexpression of Bcl-2 inhibited confluent cell death, suggesting the involvement of mitochondria-dependent pathway in confluent cell death. Interestingly, the activity of phospho-Erk (p-Erk) was initially decreased before confluence, but markedly increased after confluence. Immunofluorescence staining studies showed that p-Erk was expressed exclusively on dome-forming cells that underwent apoptosis. Treatment of confluent MDCK cells with PD98059 and UO126, the inhibitors of MEK, enhanced apoptosis as well as activity of caspase-8. These data indicate that elevation of p-Erk activity during confluence may serve to suppress confluent cell death. Taken together, activation of caspase-8 contributes to and results in confluent cell death, whereas elevated p-Erk activity serves to prevent confluent cell death by regulating activation of caspase-8.

  5. Catching up with solid tumor oncology: what is the evidence for a prognostic role of programmed cell death-ligand 1/programmed cell death-1 expression in B-cell lymphomas?

    PubMed Central

    McClanahan, Fabienne; Sharp, Thomas G.; Gribben, John G.

    2016-01-01

    Therapeutic strategies targeting the programmed cell death-ligand 1/programmed cell death-1 pathway have shown significant responses and good tolerability in solid malignancies. Although preclinical studies suggest that inhibiting programmed cell death-ligand 1/programmed cell death-1 interactions might also be highly effective in hematological malignancies, remarkably few clinical trials have been published. Determining patients who will benefit most from programmed cell death-ligand 1/programmed cell death-1-directed immunotherapy and whether programmed cell death-ligand 1/programmed cell death-1 are adequate prognostic markers becomes an increasingly important clinical question, especially as aberrant programmed cell death-ligand 1/programmed cell death-1 expression are key mediators of impaired anti-tumor immune responses in a range of B-cell lymphomas. Herein, we systematically review the published literature on the expression and prognostic value of programmed cell death-ligand 1/programmed cell death-1 in these patients and identify considerable differences in expression patterns, distribution and numbers of programmed cell death-ligand 1+/programmed cell death-1+cells, both between and within lymphoma subtypes, which is reflected in conflicting findings regarding the prognostic value of programmed cell death-ligand 1+/programmed cell death-1+ cells. This can be partly explained by differences in methodologies (techniques, protocols, cutoff values) and definitions of positivity. Moreover, lymphomagenesis, disease progression, and prognosis appear to be determined not only by the presence, numbers and distribution of specific subtypes of T cells, but also by other cells and additional immune checkpoints. Collectively, our findings indicate that programmed cell death-ligand 1/programmed cell death-1 interactions play an essential role in B-cell lymphoma biology and are of clinical importance, but that the overall outcome is determined by additional components

  6. Temporal rhythm of petal programmed cell death in Ipomoea purpurea.

    PubMed

    Gui, M-Y; Ni, X-L; Wang, H-B; Liu, W-Z

    2016-09-01

    Flowers are the main sexual reproductive organs in plants. The shapes, colours and scents of corolla of plant flowers are involved in attracting insect pollinators and increasing reproductive success. The process of corolla senescence was investigated in Ipomoea purpurea (Convolvulaceae) in this study. In the research methods of plant anatomy, cytology, cell chemistry and molecular biology were used. The results showed that at the flowering stage cells already began to show distortion, chromatin condensation, mitochondrial membrane degradation and tonoplast dissolution and rupture. At this stage genomic DNA underwent massive but gradual random degradation. However, judging from the shape and structure, aging characteristics did not appear until the early flower senescence stage. The senescence process was slow, and it was completed at the late stage of flower senescence with a withering corolla. We may safely arrive at the conclusion that corolla senescence of I. purpurea was mediated by programmed cell death (PCD) that occurred at the flowering stage. The corolla senescence exhibited an obvious temporal rhythm, which demonstrated a high degree of coordination with pollination and fertilization. PMID:27259176

  7. Autophagy mediates phase transitions from cell death to life.

    PubMed

    Han, Kyungreem; Kim, Jinwoong; Choi, MooYoung

    2015-09-01

    Autophagy is a lysosomal degradation pathway, which is critical for maintaining normal cellular functions. Despite considerable advances in defining the specific molecular mechanism governing the autophagy pathway during the last decades, we are still far from understanding the underlying principle of the autophagy machinery and its complex role in human disease. As an alternative attempt to reinvigorate the search for the principle of the autophagy pathway, we in this study make use of the computer-aided analysis, complementing current molecular-level studies of autophagy. Specifically, we propose a hypothesis that autophagy mediates cellular phase transitions and demonstrate that the autophagic phase transitions are essential to the maintenance of normal cellular functions and critical in the fate of a cell, i.e., cell death or survival. This study should provide valuable insight into how interactions of sub-cellular components such as genes and protein modules/complexes regulate autophagy and then impact on the dynamic behaviors of living cells as a whole, bridging the microscopic molecular-level studies and the macroscopic cellular-level and physiological approaches. PMID:27441218

  8. Ganglioside GD2 in reception and transduction of cell death signal in tumor cells

    PubMed Central

    2014-01-01

    Background Ganglioside GD2 is expressed on plasma membranes of various types of malignant cells. One of the most promising approaches for cancer immunotherapy is the treatment with monoclonal antibodies recognizing tumor-associated markers such as ganglioside GD2. It is considered that major mechanisms of anticancer activity of anti-GD2 antibodies are complement-dependent cytotoxicity and/or antibody-mediated cellular cytotoxicity. At the same time, several studies suggested that anti-GD2 antibodies are capable of direct induction of cell death of number of tumor cell lines, but it has not been investigated in details. In this study we investigated the functional role of ganglioside GD2 in the induction of cell death of multiple tumor cell lines by using GD2-specific monoclonal antibodies. Methods Expression of GD2 on different tumor cell lines was analyzed by flow cytometry using anti-GD2 antibodies. By using HPTLC followed by densitometric analysis we measured the amount of ganglioside GD2 in total ganglioside fractions isolated from tumor cell lines. An MTT assay was performed to assess viability of GD2-positive and -negative tumor cell lines treated with anti-GD2 mAbs. Cross-reactivity of anti-GD2 mAbs with other gangliosides or other surface molecules was investigated by ELISA and flow cytometry. Inhibition of GD2 expression was achieved by using of inhibitor for ganglioside synthesis PDMP and/or siRNA for GM2/GD2 and GD3 synthases. Results Anti-GD2 mAbs effectively induced non-classical cell death that combined features of both apoptosis and necrosis in GD2-positive tumor cells and did not affect GD2-negative tumors. Anti-GD2 mAbs directly induced cell death, which included alteration of mitochondrial membrane potential, induction of apoptotic volume decrease and cell membrane permeability. This cytotoxic effect was mediated exclusively by specific binding of anti-GD2 antibodies with ganglioside GD2 but not with other molecules. Moreover, the level of GD2

  9. Oxidative Stress, Cell Death, and Other Damage to Alveolar Epithelial Cells Induced by Cigarette Smoke

    PubMed Central

    Aoshiba, K; Nagai, A

    2003-01-01

    Cigarette smoking is a major risk factor in the development of various lung diseases, including pulmonary emphysema, pulmonary fibrosis, and lung cancer. The mechanisms of these diseases include alterations in alveolar epithelial cells, which are essential in the maintenance of normal alveolar architecture and function. Following cigarette smoking, alterations in alveolar epithelial cells induce an increase in epithelial permeability, a decrease in surfactant production, the inappropriate production of inflammatory cytokines and growth factors, and an increased risk of lung cancer. However, the most deleterious effect of cigarette smoke on alveolar epithelial cells is cell death, i.e., either apoptosis or necrosis depending on the magnitude of cigarette smoke exposure. Cell death induced by cigarette smoke exposure can largely be accounted for by an enhancement in oxidative stress. In fact, cigarette smoke contains and generates many reactive oxygen species that damage alveolar epithelial cells. Whether apoptosis and/or necrosis in alveolar epithelial cells is enhanced in healthy cigarette smokers is presently unclear. However, recent evidence indicates that the apoptosis of alveolar epithelial cells and alveolar endothelial cells is involved in the pathogenesis of pulmonary emphysema, an important cigarette smoke-induced lung disease characterized by the loss of alveolar structures. This review will discuss oxidative stress, cell death, and other damage to alveolar epithelial cells induced by cigarette smoke. PMID:19570263

  10. Oxidative Stress, Cell Death, and Other Damage to Alveolar Epithelial Cells Induced by Cigarette Smoke

    PubMed Central

    Aoshiba, K; Nagai, A

    2003-01-01

    Cigarette smoking is a major risk factor in the development of various lung diseases, including pulmonary emphysema, pulmonary fibrosis, and lung cancer. The mechanisms of these diseases include alterations in alveolar epithelial cells, which are essential in the maintenance of normal alveolar architecture and function. Following cigarette smoking, alterations in alveolar epithelial cells induce an increase in epithelial permeability, a decrease in surfactant production, the inappropriate production of inflammatory cytokines and growth factors, and an increased risk of lung cancer. However, the most deleterious effect of cigarette smoke on alveolar epithelial cells is cell death, i.e., either apoptosis or necrosis depending on the magnitude of cigarette smoke exposure. Cell death induced by cigarette smoke exposure can largely be accounted for by an enhancement in oxidative stress. In fact, cigarette smoke contains and generates many reactive oxygen species that damage alveolar epithelial cells. Whether apoptosis and/or necrosis in alveolar epithelial cells is enhanced in healthy cigarette smokers is presently unclear. However, recent evidence indicates that the apoptosis of alveolar epithelial cells and alveolar endothelial cells is involved in the pathogenesis of pulmonary emphysema, an important cigarette smoke-induced lung disease characterized by the loss of alveolar structures. This review will discuss oxidative stress, cell death, and other damage to alveolar epithelial cells induced by cigarette smoke.

  11. Artocarpus communis Induces Autophagic Instead of Apoptotic Cell Death in Human Hepatocellular Carcinoma Cells.

    PubMed

    Tzeng, Cheng-Wei; Tzeng, Wen-Sheng; Lin, Liang-Tzung; Lee, Chiang-Wen; Yen, Ming-Hong; Yen, Feng-Lin; Lin, Chun-Ching

    2015-01-01

    For centuries, natural plant extracts have played an important role in traditional medicine for curing and preventing diseases. Studies have revealed that Artocarpus communis possess various bioactivities, such as anti-inflammation, anti-oxidant, and anticancer activities. A. communis offers economic value as a source of edible fruit, yields timber, and is widely used in folk medicines. However, little is known about its molecular mechanisms of anticancer activity. Here, we demonstrate the antiproliferative activity of A. communis methanol extract (AM) and its dichloromethane fraction (AD) in two human hepatocellular carcinoma (HCC) cell lines, HepG2 and PLC/PRF/5. Colony assay showed the long-term inhibitory effect of both extracts on cell growth. DNA laddering and immunoblotting analyses revealed that both extracts did not induce apoptosis in the hepatoma cell lines. AM and AD-treated cells demonstrated different cell cycle distribution compared to UV-treated cells, which presented apoptotic cell death with high sub-G1 ratio. Instead, acridine orange staining revealed that AM and AD triggered autophagosome accumulation. Immunoblotting showed a significant expression of autophagy-related proteins, which indicated the autophagic cell death (ACD) of hepatoma cell lines. This study therefore demonstrates that A. communis AM and its dichloromethane fraction can induce ACD in HCC cells and elucidates the potential of A. communis extracts for development as anti tumor therapeutic agents that utilize autophagy as mechanism in mediating cancer cell death.

  12. Artocarpus communis Induces Autophagic Instead of Apoptotic Cell Death in Human Hepatocellular Carcinoma Cells.

    PubMed

    Tzeng, Cheng-Wei; Tzeng, Wen-Sheng; Lin, Liang-Tzung; Lee, Chiang-Wen; Yen, Ming-Hong; Yen, Feng-Lin; Lin, Chun-Ching

    2015-01-01

    For centuries, natural plant extracts have played an important role in traditional medicine for curing and preventing diseases. Studies have revealed that Artocarpus communis possess various bioactivities, such as anti-inflammation, anti-oxidant, and anticancer activities. A. communis offers economic value as a source of edible fruit, yields timber, and is widely used in folk medicines. However, little is known about its molecular mechanisms of anticancer activity. Here, we demonstrate the antiproliferative activity of A. communis methanol extract (AM) and its dichloromethane fraction (AD) in two human hepatocellular carcinoma (HCC) cell lines, HepG2 and PLC/PRF/5. Colony assay showed the long-term inhibitory effect of both extracts on cell growth. DNA laddering and immunoblotting analyses revealed that both extracts did not induce apoptosis in the hepatoma cell lines. AM and AD-treated cells demonstrated different cell cycle distribution compared to UV-treated cells, which presented apoptotic cell death with high sub-G1 ratio. Instead, acridine orange staining revealed that AM and AD triggered autophagosome accumulation. Immunoblotting showed a significant expression of autophagy-related proteins, which indicated the autophagic cell death (ACD) of hepatoma cell lines. This study therefore demonstrates that A. communis AM and its dichloromethane fraction can induce ACD in HCC cells and elucidates the potential of A. communis extracts for development as anti tumor therapeutic agents that utilize autophagy as mechanism in mediating cancer cell death. PMID:25967668

  13. Contact-independent cell death of human microglial cells due to pathogenic Naegleria fowleri trophozoites.

    PubMed

    Kim, Jong-Hyun; Kim, Daesik; Shin, Ho-Joon

    2008-12-01

    Free-living Naegleria fowleri leads to a fatal infection known as primary amebic meningoencephalitis in humans. Previously, the target cell death could be induced by phagocytic activity of N. fowleri as a contact-dependent mechanism. However, in this study we investigated the target cell death under a non-contact system using a tissue-culture insert. The human microglial cells, U87MG cells, co-cultured with N. fowleri trophozoites for 30 min in a non-contact system showed morphological changes such as the cell membrane destruction and a reduction in the number. By fluorescence-activated cell sorter (FACS) analysis, U87MG cells co-cultured with N. fowleri trophozoites in a non-contact system showed a significant increase of apoptotic cells (16%) in comparison with that of the control or N. fowleri lysate. When U87MG cells were co-cultured with N. fowleri trophozoites in a non-contact system for 30 min, 2 hr, and 4 hr, the cytotoxicity of amebae against target cells was 40.5, 44.2, and 45.6%, respectively. By contrast, the cytotoxicity of non-pathogenic N. gruberi trophozoites was 10.2, 12.4, and 13.2%, respectively. These results suggest that the molecules released from N. fowleri in a contact-independent manner as well as phagocytosis in a contact-dependent manner may induce the host cell death.

  14. A High Concentration of Genistein Induces Cell Death in Human Uterine Leiomyoma Cells by Autophagy

    PubMed Central

    Castro, Lysandra; Gao, Xioahua; Moore, Alicia B; Yu, Linda; Di, Xudong; Kissling, Grace E; Dixon, Darlene

    2016-01-01

    Genistein, an estrogenic, soy-derived isoflavone, may play a protective role against hormone-related cancers. We have reported that a high concentration of genistein inhibits cell proliferation and induces apoptosis in human uterine smooth muscle cells, but not in leiomyoma (fibroid) cells. To better understand the differential cell death responses of normal and tumor cells to a high concentration of genistein, we treated uterine smooth muscle cells and uterine leiomyoma cells with 50 μg/ml of genistein for 72 h and 168 h, and assessed for mediators of apoptosis, cytotoxicity and autophagy. We found that leiomyoma cells had increased protection from apoptosis by expressing an increased ratio of Bcl-2: bak at 72 h and 168 h; however, in smooth muscle cells, the Bcl-2: bak ratio was decreased at 72 h, but significantly rebounded by 168 h. The apoptosis extrinsic factors, Fas ligand and Fas receptor, were highly expressed in uterine smooth muscle cells following genistein treatment at both time points as evidenced by confocal microscopy. This was not seen in the uterine leiomyoma cells; however, cytotoxicity as indicated by elevated lactate dehydrogenase levels was significantly enhanced at 168 h. Increased immunoexpression of an autophagy/autophagosome marker was also observed in the leiomyoma cells, although minimally present in smooth muscle cells at 72 h. Ultrastructurally, there was evidence of autophagic vacuoles in the leiomyoma cells; whereas, the normal smooth muscle cells showed nuclear fragmentation indicative of apoptosis. In summary, our data show differential cell death pathways induced by genistein in tumor and normal uterine smooth muscle cells, and suggest novel cell death pathways that can be targeted for preventive and intervention strategies for inhibiting fibroid tumor cell growth in vivo. PMID:27512718

  15. Tomato Phospholipid Hydroperoxide Glutathione Peroxidase Inhibits Cell Death Induced by Bax and Oxidative Stresses in Yeast and Plants1

    PubMed Central

    Chen, Shaorong; Vaghchhipawala, Zarir; Li, Wei; Asard, Han; Dickman, Martin B.

    2004-01-01

    Using a conditional life or death screen in yeast, we have isolated a tomato (Lycopersicon esculentum) gene encoding a phospholipid hydroperoxide glutathione peroxidase (LePHGPx). The protein displayed reduced glutathione-dependent phospholipid hydroperoxide peroxidase activity, but differs from counterpart mammalian enzymes that instead contain an active seleno-Cys. LePHGPx functioned as a cytoprotector in yeast (Saccharomyces cerevisiae), preventing Bax, hydrogen peroxide, and heat stress induced cell death, while also delaying yeast senescence. When tobacco (Nicotiana tabacum) leaves were exposed to lethal levels of salt and heat stress, features associated with mammalian apoptosis were observed. Importantly, transient expression of LePHGPx protected tobacco leaves from salt and heat stress and suppressed the apoptotic-like features. As has been reported, conditional expression of Bax was lethal in tobacco, resulting in tissue collapse and membrane permeability to Evans blue. When LePHGPx was coexpressed with Bax, little cell death and no vital staining were observed. Moreover, stable expression of LePHGPx in tobacco conferred protection against the fungal phytopathogen Botrytis cinerea. Taken together, our data indicated that LePHGPx can protect plant tissue from a variety of stresses. Moreover, functional screens in yeast are a viable tool for the identification of plant genes that regulate cell death. PMID:15235116

  16. Fusaric acid induction of programmed cell death modulated through nitric oxide signalling in tobacco suspension cells.

    PubMed

    Jiao, Jiao; Zhou, Benguo; Zhu, Xiaoping; Gao, Zhengliang; Liang, Yuancun

    2013-10-01

    Fusaric acid (FA) is a nonhost-selective toxin mainly produced by Fusarium oxysporum, the causal agent of plant wilt diseases. We demonstrate that FA can induce programmed cell death (PCD) in tobacco suspension cells and the FA-induced PCD is modulated by nitric oxide (NO) signalling. Cells undergoing cell death induced by FA treatment exhibited typical characteristics of PCD including cytoplasmic shrinkage, chromatin condensation, DNA fragmentation, membrane plasmolysis, and formation of small cytoplasmic vacuoles. In addition, caspase-3-like activity was activated upon the FA treatment. The process of FA-induced PCD was accompanied by a rapid accumulation of NO in a FA dose-dependent manner. Pre-treatment of cells with NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) or NO synthase inhibitor N(G)-monomethyl-arginine monoacetate (L-NMMA) significantly reduced the rate of FA-induced cell death. Furthermore, the caspase-3-like activity and the expression of PAL and Hsr203J genes were alleviated by application of cPTIO or L-NMMA to FA-treated tobacco cells. This indicates that NO is an important factor involved in the FA-induced PCD. Our results also show that pre-treatment of tobacco cells with a caspase-3-specific inhibitor, Ac-DEVD-CHO, can reduce the rate of FA-induced cell death. These results demonstrate that the FA-induced cell death is a PCD and is modulated by NO signalling through caspase-3-like activation. PMID:23838885

  17. Eiger-induced cell death relies on Rac1-dependent endocytosis

    PubMed Central

    Ruan, W; Srinivasan, A; Lin, S; Kara, k-I; Barker, P A

    2016-01-01

    Signaling via tumor necrosis factor receptor (TNFR) superfamily members regulates cellular life and death decisions. A subset of mammalian TNFR proteins, most notably the p75 neurotrophin receptor (p75NTR), induces cell death through a pathway that requires activation of c-Jun N-terminal kinases (JNKs). However the receptor-proximal signaling events that mediate this remain unclear. Drosophila express a single tumor necrosis factor (TNF) ligand termed Eiger (Egr) that activates JNK-dependent cell death. We have exploited this model to identify phylogenetically conserved signaling events that allow Egr to induce JNK activation and cell death in vivo. Here we report that Rac1, a small GTPase, is specifically required in Egr-mediated cell death. rac1 loss of function blocks Egr-induced cell death, whereas Rac1 overexpression enhances Egr-induced killing. We identify Vav as a GEF for Rac1 in this pathway and demonstrate that dLRRK functions as a negative regulator of Rac1 that normally acts to constrain Egr-induced death. Thus dLRRK loss of function increases Egr-induced cell death in the fly. We further show that Rac1-dependent entry of Egr into early endosomes is a crucial prerequisite for JNK activation and for cell death and show that this entry requires the activity of Rab21 and Rab7. These findings reveal novel regulatory mechanisms that allow Rac1 to contribute to Egr-induced JNK activation and cell death. PMID:27054336

  18. Eiger-induced cell death relies on Rac1-dependent endocytosis.

    PubMed

    Ruan, W; Srinivasan, A; Lin, S; Kara, k-I; Barker, P A

    2016-01-01

    Signaling via tumor necrosis factor receptor (TNFR) superfamily members regulates cellular life and death decisions. A subset of mammalian TNFR proteins, most notably the p75 neurotrophin receptor (p75NTR), induces cell death through a pathway that requires activation of c-Jun N-terminal kinases (JNKs). However the receptor-proximal signaling events that mediate this remain unclear. Drosophila express a single tumor necrosis factor (TNF) ligand termed Eiger (Egr) that activates JNK-dependent cell death. We have exploited this model to identify phylogenetically conserved signaling events that allow Egr to induce JNK activation and cell death in vivo. Here we report that Rac1, a small GTPase, is specifically required in Egr-mediated cell death. rac1 loss of function blocks Egr-induced cell death, whereas Rac1 overexpression enhances Egr-induced killing. We identify Vav as a GEF for Rac1 in this pathway and demonstrate that dLRRK functions as a negative regulator of Rac1 that normally acts to constrain Egr-induced death. Thus dLRRK loss of function increases Egr-induced cell death in the fly. We further show that Rac1-dependent entry of Egr into early endosomes is a crucial prerequisite for JNK activation and for cell death and show that this entry requires the activity of Rab21 and Rab7. These findings reveal novel regulatory mechanisms that allow Rac1 to contribute to Egr-induced JNK activation and cell death. PMID:27054336

  19. Endothelial cell loss is not a major cause of neuronal and glial cell death following contusion injury of the spinal cord.

    PubMed

    Casella, Gizelda T B; Bunge, Mary Bartlett; Wood, Patrick M

    2006-11-01

    Contusion of the spinal cord causes an immediate local loss of neurons and disruption of vasculature; additional loss continues thereafter. To explore the possibility of a causal link between delayed endothelial cell (EC) death and secondary neural cell loss, we evaluated neural and endothelial cell survival, and measured inflammatory cell infiltration, at times up to 48 h after contusion injury to the adult rat thoracic spinal cord. Female Fischer rats (200 g), subjected to moderate (10 g x 12.5 mm) weight drop injuries by the MASCIS (NYU) impactor, were analyzed at 15 min and at 1, 8, 24 and 48 h. ECs, neurons, astrocytes, oligodendrocytes, neutrophils and activated macrophages/microglia were counted in transverse sections. At the injury site, 90% of all neurons died within 48 h of injury; no medium-large diameter neurons survived beyond 48 h. EC death occurred with kinetics similar to glial cell death. Because, in the injury site, most cell death occurred before 8 h, it preceded inflammatory cell infiltration. Three millimeters rostral and caudal to the injury epicenter neuronal numbers were stable for 8 h, and a sharp decrease in neuronal numbers beginning at 8 h strongly correlated with the onset of inflammatory cell infiltration. Glial and blood vessel numbers remained relatively stable in these areas up to 48 h. These results suggest that the loss of ECs during the first 48 h after a contusion injury is not a major cause of neuronal and glial cell death and, in tissue adjacent to the epicenter, inflammatory cell infiltration leads to neuronal loss. PMID:16872600

  20. Cell Death Conversion under Hypoxic Condition in Tumor Development and Therapy

    PubMed Central

    Qiu, Yu; Li, Peng; Ji, Chunyan

    2015-01-01

    Hypoxia, which is common during tumor progression, plays important roles in tumor biology. Failure in cell death in response to hypoxia contributes to progression and metastasis of tumors. On the one hand, the metabolic and oxidative stress following hypoxia could lead to cell death by triggering signal cascades, like LKB1/AMPK, PI3K/AKT/mTOR, and altering the levels of effective components, such as the Bcl-2 family, Atg and p62. On the other hand, hypoxia-induced autophagy can serve as a mechanism to turn over nutrients, so as to mitigate the adverse condition and then avoid cell death potentially. Due to the effective role of hypoxia, this review focuses on the crosstalk in cell death under hypoxia in tumor progression. Additionally, the illumination of cell death in hypoxia could shed light on the clinical applications of cell death targeted therapy. PMID:26512660

  1. Mcl-1 protects prostate cancer cells from cell death mediated by chemotherapy-induced DNA damage

    PubMed Central

    Reiner, Teresita; de las Pozas, Alicia; Parrondo, Ricardo; Palenzuela, Deanna; Cayuso, William; Rai, Priyamvada; Perez-Stable, Carlos

    2015-01-01

    The anti-apoptotic protein Mcl-1 is highly expressed in castration-resistant prostate cancer (CRPC), resulting in resistance to apoptosis and association with poor prognosis. Although predominantly localized in the cytoplasm, there is evidence that Mcl-1 exhibits nuclear localization where it is thought to protect against DNA damage-induced cell death. The role of Mcl-1 in mediating resistance to chemotherapy-induced DNA damage in prostate cancer (PCa) is not known. We show in human PCa cell lines and in TRAMP, a transgenic mouse model of PCa, that the combination of the antimitotic agent ENMD-1198 (analog of 2-methoxyestradiol) with betulinic acid (BA, increases proteotoxic stress) targets Mcl-1 by increasing its proteasomal degradation, resulting in increased γH2AX (DNA damage) and apoptotic/necrotic cell death. Knockdown of Mcl-1 in CRPC cells leads to elevated γH2AX, DNA strand breaks, and cell death after treatment with 1198 + BA- or doxorubicin. Additional knockdowns in PC3 cells suggests that cytoplasmic Mcl-1 protects against DNA damage by blocking the mitochondrial release of apoptosis-inducing factor and thereby preventing its nuclear translocation and subsequent interaction with the cyclophilin A endonuclease. Overall, our results suggest that chemotherapeutic agents that target Mcl-1 will promote cell death in response to DNA damage, particularly in CRPC. PMID:26425662

  2. Gingerol sensitizes TRAIL-induced apoptotic cell death of glioblastoma cells

    SciTech Connect

    Lee, Dae-Hee; Kim, Dong-Wook; Jung, Chang-Hwa; Lee, Yong J.; Park, Daeho

    2014-09-15

    Glioblastoma multiforme (GBM) is the most lethal and aggressive astrocytoma of primary brain tumors in adults. Although there are many clinical trials to induce the cell death of glioblastoma cells, most glioblastoma cells have been reported to be resistant to TRAIL-induced apoptosis. Here, we showed that gingerol as a major component of