BH3-only Protein Noxa Is a Mediator of Hypoxic Cell Death Induced by Hypoxia-inducible Factor 1α

Hypoxia is a common cause of cell death and is implicated in many disease processes including stroke and chronic degenerative disorders. In response to hypoxia, cells express a variety of genes, which allow adaptation to altered metabolic demands, decreased oxygen demands, and the removal of irreversibly damaged cells. Using polymerase chain reaction–based suppression subtractive hybridization to find genes that are differentially expressed in hypoxia, we identified the BH3-only Bcl-2 family protein Noxa. Noxa is a candidate molecule mediating p53-induced apoptosis. We show that Noxa promoter responds directly to hypoxia via hypoxia-inducible factor (HIF)-1α. Suppression of Noxa expression by antisense oligonucleotides rescued cells from hypoxia-induced cell death and decreased infarction volumes in an animal model of ischemia. Further, we show that reactive oxygen species and resultant cytochrome c release participate in Noxa-mediated hypoxic cell death. Altogether, our results show that Noxa is induced by HIF-1α and mediates hypoxic cell death.

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Gonadotrophins modulate cell death-related genes expression in human endometrium

Hormone Molecular Biology and Clinical Investigation ◽

10.1515/hmbci-2019-0074 ◽

2020 ◽

Vol 41 (2) ◽

Author(s):

Sandro Sacchi ◽

Paola Sena ◽

Chiara Addabbo ◽

Erika Cuttone ◽

Antonio La Marca

Keyword(s):

Cell Death ◽

Quantitative Polymerase Chain Reaction ◽

Hypoxia Inducible Factor ◽

Endometrial Cells ◽

Microtubule Associated Proteins ◽

Genes Expression ◽

Associated Proteins ◽

Polymerase Chain ◽

Cytochrome P450 Family ◽

Apoptosis Marker

AbstractBackgroundGonadotrophins exert their functions by binding follicle-stimulating hormone receptor (FSHR) or luteinizing hormone and human chorionic gonadotropin receptor (LHCGR) present on endometrium. Within ovaries, FSH induces autophagy and apoptosis of granulosa cells leading to atresia of non-growing follicles, whereas hCG and LH have anti-apoptotic functions. Endometrial cells express functioning gonadotrophin receptors. The objective of this study was to analyze the effect of gonadotrophins on physiology and endometrial cells survival.Materials and methodsCollected endometria were incubated for 48 or 72 h with 100 ng/mL of recombinant human FSH (rhFSH), recombinant human LH (rhLH) or highly purified hCG (HPhCG) alone or combined. Controls omitted gonadotrophins. The effect of gonadotrophins on cytochrome P450 family 11 subfamily A polypeptide 1 (CYP11A1), hypoxia inducible factor 1α (HIF1A), and cell-death-related genes expression was evaluated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Immunohistochemistry for microtubule-associated proteins 1A/1B light chain 3B (MAP1LC3B) and apoptotic protease activating factor 1 (APAF-1) was performed.ResultsGonadotrophins are able to modulate the endometrial cells survival. FSH induced autophagy and apoptosis by increasing the relative expression of MAP1LC3B and FAS receptor. In FSH-treated samples, expression of apoptosis marker APAF-1 was detected and co-localized on autophagic cells. hCG and LH does not modulate the expression of cell-death-related genes while the up-regulation of pro-proliferative epiregulin gene was observed. When combined with FSH, hCG and LH prevent autophagy and apoptosis FSH-induced.ConclusionsDifferent gonadotrophins specifically affect endometrial cells viability differently: FSH promotes autophagy and apoptosis while LH and hCG alone or combined with rhFSH does not.

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Sensitization for γ-Irradiation-Induced Apoptosis by Smac.

Blood ◽

10.1182/blood.v104.11.3392.3392 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3392-3392

Author(s):

Stavros Giagkousiklidis ◽

Hubert Kasperczyk ◽

Meike Vogler ◽

Klaus-Michael Debatin ◽

Simone Fulda

Keyword(s):

Cell Death ◽

Tumor Cell ◽

Membrane Damage ◽

Neuroblastoma Cells ◽

Cellular Stress Response ◽

Caspase Inhibitor ◽

Cytochrome C Release ◽

Γ Irradiation ◽

Induced Apoptosis ◽

First Time

Abstract Smac is released from mitochondria during the onset of apoptosis and promotes apoptosis via abrogating the binding of Inhibitor of Apoptosis Proteins (IAPs) to caspases. γ-irradiation is one of the most commonly used therapeutic approaches in clinical oncology, which triggers cell death in tumors via DNA and/or membrane damage. Since we recently found that Smac agonists sensitized even resistant tumors for apoptosis induced by death receptor ligation or anticancer drugs, we investigated the effect of Smac agonists on apoptosis following γ-irradiation in the present study. Here, we report for the first time that overexpression of mitochondrial or cytosolic Smac significantly increased radiosensitivity of various cancers. Transfection-enforced expression of Smac strongly enhanced apoptosis upon γ-irradiation in SH-EP neuroblastoma cells, which were resistant to g-irradiation in the absence of Smac. Importantly, Smac overexpression also reduced clonogenic tumor cell survival following γ-irradiation. Analysis of signaling pathways revealed that overexpression of Smac resulted in more rapid and more potent activation of caspase pathways, e.g caspase-2, -3,- 8, -9. The broad range caspase inhibitor zVAD.fmk abrogated apoptosis upon γ-irradiation indicating that apoptosis was mediated by caspases. In addition, overexpression of Smac promoted loss of mitochondrial membrane potential and cytochrome c release upon γ-irradiation. Interestingly, γ-irradiation-induced mitochondrial perturbations were blocked in the presence of the caspase inhibitor zVAD.fmk suggesting that caspase activity was required for mitochondrial alterations in response to γ-irradiation. Notably, cell cycle alterations and activation of NF-κB occured in a similar manner in vector control and Smac-transfected cells suggesting that Smac did not significantly alter the initial cellular stress response upon γ-irradiation. Importantly, Smac overexpression sensitized various tumor cell lines for γ-irradiation-induced apoptosis, indicating that the sensitization effect of Smac for γ-irradiation was not restricted to a particular cell type. By demonstrating that Smac can sensitize various tumor cells towards γ-irradiation-induced cell death, our findings provide for the first time evidence that Smac agonists may be a useful tool to enhance radiosensitivity in a variety of human cancers.

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High-Dialysate-Glucose-Induced Oxidative Stress and Mitochondrial-Mediated Apoptosis in Human Peritoneal Mesothelial Cells

Oxidative Medicine and Cellular Longevity ◽

10.1155/2014/642793 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 9

Author(s):

Kuan-Yu Hung ◽

Shin-Yun Liu ◽

Te-Cheng Yang ◽

Tien-Ling Liao ◽

Shu-Huei Kao

Keyword(s):

Cell Death ◽

Mitochondrial Dysfunction ◽

Mesothelial Cells ◽

Cytochrome C Release ◽

Dialysis Adequacy ◽

Peritoneal Mesothelial Cells ◽

Functional Changes ◽

Key Factor ◽

Human Peritoneal Mesothelial Cells ◽

Induced Apoptosis

Human peritoneal mesothelial cells (HPMCs) are a critical component of the peritoneal membrane and play a pivotal role in dialysis adequacy. Loss of HPMCs can contribute to complications in peritoneal dialysis. Compelling evidence has shown that high-dialysate glucose is a key factor causing functional changes and cell death in HPMCs. We investigated the mechanism of HPMC apoptosis induced by high-dialysate glucose, particularly the role of mitochondria in the maintenance of HPMCs. HPMCs were incubated at glucose concentrations of 5 mM, 84 mM, 138 mM, and 236 mM. Additionally, N-acetylcysteine (NAC) was used as an antioxidant to clarify the mechanism of high-dialysate-glucose-induced apoptosis. Exposing HPMCs to high-dialysate glucose resulted in substantial apoptosis with cytochrome c release, followed by caspase activation and poly(ADP-ribose) polymerase cleavage. High-dialysate glucose induced excessive reactive oxygen species production and lipid peroxidation as well as oxidative damage to DNA. Mitochondrial fragmentation, multiple mitochondrial DNA deletions, and dissipation of the mitochondrial membrane potential were also observed. The mitochondrial dysfunction and cell death were suppressed using NAC. These results indicated that mitochondrial dysfunction is one of the main causes of high-dialysate-glucose-induced HPMC apoptosis.

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Inhibition of NGF deprivation–induced death by low oxygen involves suppression of BIMEL and activation of HIF-1

The Journal of Cell Biology ◽

10.1083/jcb.200407079 ◽

2005 ◽

Vol 168 (6) ◽

pp. 911-920 ◽

Cited By ~ 31

Author(s):

Liang Xie ◽

Randall S. Johnson ◽

Robert S. Freeman

Keyword(s):

Cell Death ◽

Cytochrome C ◽

Protective Effect ◽

Sympathetic Neurons ◽

Hypoxia Inducible Factor ◽

Trophic Factor ◽

Low Oxygen ◽

Cytochrome C Release ◽

Targeted Deletion ◽

Trophic Factor Deprivation

Changes in O2 tension can significantly impact cell survival, yet the mechanisms underlying these effects are not well understood. Here, we report that maintaining sympathetic neurons under low O2 inhibits apoptosis caused by NGF deprivation. Low O2 exposure blocked cytochrome c release after NGF withdrawal, in part by suppressing the up-regulation of BIMEL. Forced BIMEL expression removed the block to cytochrome c release but did not prevent protection by low O2. Exposing neurons to low O2 also activated hypoxia-inducible factor (HIF) and expression of a stabilized form of HIF-1α (HIF-1αPP→AG) inhibited cell death in normoxic, NGF-deprived cells. Targeted deletion of HIF-1α partially suppressed the protective effect of low O2, whereas deletion of HIF-1α combined with forced BIMEL expression completely reversed the ability of low O2 to inhibit cell death. These data suggest a new model for how O2 tension can influence apoptotic events that underlie trophic factor deprivation–induced cell death.

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Triptolide induces caspase-dependent cell death mediated via the mitochondrial pathway in leukemic cells

Blood ◽

10.1182/blood-2005-09-3898 ◽

2006 ◽

Vol 108 (2) ◽

pp. 630-637 ◽

Cited By ~ 120

Author(s):

Bing Z. Carter ◽

Duncan H. Mak ◽

Wendy D. Schober ◽

Teresa McQueen ◽

David Harris ◽

...

Keyword(s):

Cell Death ◽

Anticancer Agents ◽

Chinese Herb ◽

Mitochondrial Pathway ◽

Leukemic Cells ◽

Cytochrome C Release ◽

Knock Out ◽

Dependent Cell ◽

Induced Apoptosis

Triptolide, a diterpenoid isolated from the Chinese herb Tripterygium wilfordii Hook.f, has shown antitumor activities in a broad range of solid tumors. Here, we examined its effects on leukemic cells and found that, at 100 nM or less, it potently induced apoptosis in various leukemic cell lines and primary acute myeloid leukemia (AML) blasts. We then attempted to identify its mechanisms of action. Triptolide induced caspase-dependent cell death accompanied by a significant decrease in XIAP levels. Forced XIAP overexpression attenuated triptolide-induced cell death. Triptolide also decreased Mcl-1 but not Bcl-2 and Bcl-XL levels. Bcl-2 overexpression suppressed triptolide-induced apoptosis. Further, triptolide induced loss of the mitochondrial membrane potential and cytochrome C release. Caspase-9 knock-out cells were resistant, while caspase-8–deficient cells were sensitive to triptolide, suggesting criticality of the mitochondrial but not the death receptor pathway for triptolide-induced apoptosis. Triptolide also enhanced cell death induced by other anticancer agents. Collectively, our results demonstrate that triptolide decreases XIAP and potently induces caspase-dependent apoptosis in leukemic cells mediated through the mitochondrial pathway at low nanomolar concentrations. The potent antileukemic activity of triptolide in vitro warrants further investigation of this compound for the treatment of leukemias and other malignancies.

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The ZIKA Virus Delays Cell Death Through the Anti-Apoptotic Bcl-2 Family Proteins

Cells ◽

10.3390/cells8111338 ◽

2019 ◽

Vol 8 (11) ◽

pp. 1338 ◽

Cited By ~ 5

Author(s):

Jonathan Turpin ◽

Etienne Frumence ◽

Philippe Desprès ◽

Wildriss Viranaicken ◽

Pascale Krejbich-Trotot

Keyword(s):

Cell Death ◽

Host Cell ◽

Zika Virus ◽

Congenital Defects ◽

Host Cell Apoptosis ◽

Family Protein ◽

Global Concern ◽

Apoptotic Pathways ◽

Induced Apoptosis ◽

Replicon Type

Zika virus (ZIKV) is an emerging human mosquito-transmitted pathogen of global concern, known to be associated with complications such as congenital defects and neurological disorders in adults. ZIKV infection is associated with induction of cell death. However, previous studies suggest that the virally induced apoptosis occurs at a slower rate compared to the course of viral production. In this present study, we investigated the capacity of ZIKV to delay host cell apoptosis. We provide evidence that ZIKV has the ability to interfere with apoptosis whether it is intrinsically or extrinsically induced. In cells expressing viral replicon-type constructions, we show that this control is achieved through replication. Finally, our work highlights an important role for anti-apoptotic Bcl-2 family protein in the ability of ZIKV to control apoptotic pathways, avoiding premature cell death and thereby promoting virus replication in the host-cell.

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Abstract 1950: Role of Superoxide, Nitric Oxide and Peroxynitrite in Doxorubicin-induced Cell Death in vitro and in vivo

Circulation ◽

10.1161/circ.116.suppl_16.ii_420-a ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Partha Mukhopadhyay ◽

Mohanraj Rajesh ◽

Sandor Bátkai ◽

György Haskó ◽

Csaba Szabo ◽

...

Keyword(s):

Cell Death ◽

Caspase 3 ◽

Superoxide Generation ◽

Cytochrome C Release ◽

Mitochondrial Superoxide ◽

Induced Apoptosis ◽

Peroxynitrite Scavengers

Although doxorubicin (DOX) is one of the most potent antitumor agents available, its clinical use is limited because of the risk of severe cardiotoxicity often leading to irreversible congestive heart failure. Apoptotic cell death is a key component in DOX-induced cardiotoxicity, but its trigger(s) and mechanisms are poorly understood. Here, we explore the role of peroxynitrite (a reactive oxidant produced from the diffusion-controlled reaction between nitric oxide and superoxide anion) in DOX-induced cell death. Using a well-established in vivo mouse model of DOX-induced acute heart failure, we demonstrate marked increases in myocardial apoptosis (caspase-3 and 9 gene expression, caspase 3 activity, cytochrome-c release, and TUNEL), iNOS but not eNOS and nNOS expression, 3-nitrotyrosine formation and a decrease in myocardial contractility following DOX treatment. Pre-treatment of mice with peroxynitrite scavengers markedly attenuated DOX-induced myocardial cell death and dysfunction without affecting iNOS expression. DOX induced increased superoxide generation and nitrotyrosine formation in the mitochondria, dissipation of mitochondrial membrane potential, apoptosis (cytochrome-C release, annexin V staining, caspase activation, nuclear fragmentation), and disruption of actin cytoskeleton structure in cardiac-derived H9c2 cells. Selective iNOS inhibitors attenuated DOX-induced apoptosis, without affecting increased mitochondrial superoxide generation, whereas NO donors increased DOX-induced cell death in vitro . The peroxynitrite scavengers FeTMPyP and MnTMPyP markedly reduced both DOX- or peroxynitrite-induced nitrotyrosine formation and cell death in vitro , without affecting DOX-induced increased mitochondrial superoxide formation. Thus, peroxynitrite is a major trigger of DOX-induced apoptosis, and its effective neutralization can be of significant therapeutic benefit.

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Caspase-dependent cytochrome c release and cell death in chick cardiomyocytes after simulated ischemia-reperfusion

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.01063.2003 ◽

2004 ◽

Vol 286 (6) ◽

pp. H2280-H2286 ◽

Cited By ~ 32

Author(s):

Yimin Qin ◽

Terry L. Vanden Hoek ◽

Kim Wojcik ◽

Travis Anderson ◽

Chang-Qing Li ◽

...

Keyword(s):

Cell Death ◽

Cytochrome C ◽

Ischemia Reperfusion ◽

Caspase 8 ◽

Caspase 9 ◽

Cytochrome C Release ◽

Simulated Ischemia ◽

Baseline Levels ◽

Caspase 2 ◽

Induced Apoptosis

We recently demonstrated that reperfusion rapidly induces the mitochondrial pathway of apoptosis in chick cardiomyocytes after 1 h of simulated ischemia. Here we tested whether ischemia-reperfusion (I/R)-induced apoptosis could be initiated by caspase-dependent cytochrome c release in this model of cardiomyocyte injury. Fluorometric assays of caspase activity showed little, if any, activation of caspases above baseline levels induced by 1 h of ischemia alone. However, these assays revealed rapid activation of caspase-2, yielding a 2.95 ± 0.52-fold increase (over ischemia only) within the 1st h of reperfusion, whereas activities of caspases-3, -8, and -9 increased only slightly from their baseline levels. The rapid and prominent activation of caspase-2 suggested that it could be an important initiator caspase in this model, and using specific caspase inhibitors given only at the point of reperfusion, we tested this hypothesis. The caspase-2 inhibitor benzyloxycarbonyl-Val-Asp(Ome)-Val-Ala-Asp(Ome)-CH2F was the only caspase inhibitor that significantly inhibited cytochrome c release from mitochondria. This inhibitor also completely blocked activation of caspases-3, -8, and -9. The caspase-3/7 inhibitor transiently and only partially blocked caspase-2 activity and was less effective in blocking the activities of caspases-8 and -9. The caspase-8 inhibitor failed to significantly block caspase-2 or -3, and the caspase-9 inhibitor blocked only caspase-9. Furthermore, the caspase-2 inhibitor protected against I/R-induced cell death, but the caspase-8 inhibitor failed to do so. These data suggest that active caspase-2 initiates cytochrome c release after reperfusion and that it is critical for the I/R-induced apoptosis in this model.

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Calcineurin-mediated Bad translocation regulates cyanide-induced neuronal apoptosis

Biochemical Journal ◽

10.1042/bj20031107 ◽

2004 ◽

Vol 379 (3) ◽

pp. 805-813 ◽

Cited By ~ 25

Author(s):

Yan SHOU ◽

Li LI ◽

Krishnan PRABHAKARAN ◽

Joseph L. BOROWITZ ◽

Gary E. ISOM

Keyword(s):

Cell Death ◽

Cytochrome C ◽

Cyclosporin A ◽

Apoptotic Cell ◽

Calcineurin Inhibitors ◽

Apoptotic Response ◽

Cytochrome C Release ◽

Cortical Cells ◽

Subsequent Activation ◽

Induced Apoptosis

In cyanide-induced apoptosis, an increase in cytosolic free Ca2+ and generation of reactive oxygen species are initiation stimuli for apoptotic cell death. Previous studies have shown that cyanide-stimulated translocation of Bax (Bcl-associated X protein) to mitochondria is linked with release of cytochrome c and subsequent activation of a caspase cascade [Shou, Li, Prabhakaran, Borowitz and Isom (2003) Toxicol. Sci. 75, 99–107]. In the present study, the relationship of the cyanide-induced increase in cytosolic free Ca2+ to activation of Bad (Bcl-2/Bcl-XL-antagonist, causing cell death) was determined in cortical cells. Bad is a Ca2+-sensitive pro-apoptotic Bcl-2 protein, which on activation translocates from cytosol to mitochondria to initiate cytochrome c release. In cultured primary cortical cells, cyanide produced a concentration- and time-dependent translocation of Bad from cytosol to mitochondria. Translocation occurred early in the apoptotic response, since mitochondrial Bad was detected within 1 h of cyanide treatment. Mitochondrial levels of the protein continued to increase up to 12 h post-cyanide exposure. Concurrent with Bad translocation, a Ca2+-sensitive increase in cellular calcineurin activity was observed. Increased cytosolic Ca2+ and calcineurin activation stimulated Bad translocation since BAPTA [bis-(o-aminophenoxy)ethane-N,N,N´,N´-tetra-acetic acid], an intracellular Ca2+ chelator, and cyclosporin A, a calcineurin inhibitor, significantly reduced translocation. BAPTA also blocked release of cytochrome c from mitochondria as well as apoptosis. Furthermore, treatment of cells with the calcineurin inhibitors cyclosporin A or FK506 blocked the apoptotic response, linking calcineurin activation and the subsequent translocation of Bad to cell death. These observations show that by inducing a rapid increase in cytosolic free Ca2+, cyanide can partially initiate the apoptotic cascade through a calcineurin-mediated translocation of Bad to mitochondria.

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Identification of the Hypoxia-Inducible Factor 1α-Responsive HGTD-P Gene as a Mediator in the Mitochondrial Apoptotic Pathway

Molecular and Cellular Biology ◽

10.1128/mcb.24.9.3918-3927.2004 ◽

2004 ◽

Vol 24 (9) ◽

pp. 3918-3927 ◽

Cited By ~ 51

Author(s):

Mi-Jung Lee ◽

Jee-Youn Kim ◽

Kyoungho Suk ◽

Jae-Hoon Park

Keyword(s):

Cell Death ◽

Mitochondrial Permeability Transition ◽

Apoptotic Cell ◽

Hypoxia Inducible Factor ◽

Permeability Transition ◽

Hypoxic Cell ◽

Voltage Dependent Anion Channel ◽

Apoptotic Pathway ◽

Hypoxia Inducible Factor 1Α ◽

P Gene

ABSTRACT Hypoxia-inducible factor 1α (HIF-1α) controls the cellular responses to hypoxia, activating transcription of a range of genes involved in adaptive processes such as increasing glycolysis and promoting angiogenesis. However, paradoxically, HIF-1α also participates in hypoxic cell death. Several gene products, such as BNip3, RTP801, and Noxa, were identified as HIF-1α-responsive proapoptotic proteins, but the complicated hypoxic cell death pathways could not be completely explained by the few known genes. Moreover, molecules linking the proapoptotic signals of HIF-1α directly to mitochondrial permeability transition are missing. In this work, we report the identification of an HIF-1α-responsive proapoptotic molecule, HGTD-P. Its expression was directly regulated by HIF-1α through a hypoxia-responsive element on the HGTD-P promoter region. When overexpressed, HGTD-P was localized to mitochondria and facilitated apoptotic cell death via typical mitochondrial apoptotic cascades, including permeability transition, cytochrome c release, and caspase 9 activation. In the process of permeability transition induction, the death-inducing domain of HGTD-P physically interacted with the voltage-dependent anion channel. In addition, suppression of HGTD-P expression by small interfering RNA or antisense oligonucleotides protected against hypoxic cell death. Taken together, our data indicate that HGTD-P is a new HIF-1α-responsive proapoptotic molecule that activates mitochondrial apoptotic cascades.

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