Transient Receptor Potential Vanilloid 1 Expression Mediates Capsaicin-Induced Cell Death.

PubMed

Ramírez-Barrantes, Ricardo; Córdova, Claudio; Gatica, Sebastian; Rodriguez, Belén; Lozano, Carlo; Marchant, Ivanny; Echeverria, Cesar; Simon, Felipe; Olivero, Pablo

2018-01-01

The transient receptor potential (TRP) ion channel family consists of a broad variety of non-selective cation channels that integrate environmental physicochemical signals for dynamic homeostatic control. Involved in a variety of cellular physiological processes, TRP channels are fundamental to the control of the cell life cycle. TRP channels from the vanilloid (TRPV) family have been directly implicated in cell death. TRPV1 is activated by pain-inducing stimuli, including inflammatory endovanilloids and pungent exovanilloids, such as capsaicin (CAP). TRPV1 activation by high doses of CAP (>10 μM) leads to necrosis, but also exhibits apoptotic characteristics. However, CAP dose-response studies are lacking in order to determine whether CAP-induced cell death occurs preferentially via necrosis or apoptosis. In addition, it is not known whether cytosolic Ca 2+ and mitochondrial dysfunction participates in CAP-induced TRPV1-mediated cell death. By using TRPV1-transfected HeLa cells, we investigated the underlying mechanisms involved in CAP-induced TRPV1-mediated cell death, the dependence of CAP dose, and the participation of mitochondrial dysfunction and cytosolic Ca 2+ increase. Together, our results contribute to elucidate the pathophysiological steps that follow after TRPV1 stimulation with CAP. Low concentrations of CAP (1 μM) induce cell death by a mechanism involving a TRPV1-mediated rapid and transient intracellular Ca 2+ increase that stimulates plasma membrane depolarization, thereby compromising plasma membrane integrity and ultimately leading to cell death. Meanwhile, higher doses of CAP induce cell death via a TRPV1-independent mechanism, involving a slow and persistent intracellular Ca 2+ increase that induces mitochondrial dysfunction, plasma membrane depolarization, plasma membrane loss of integrity, and ultimately, cell death.

An endogenous 55 kDa TNF receptor mediates cell death in a neural cell line.

PubMed

Sipe, K J; Srisawasdi, D; Dantzer, R; Kelley, K W; Weyhenmeyer, J A

1996-06-01

Tumor necrosis factor-alpha (TNF) is associated with developmental and injury-related events in the central nervous system (CNS). In the present study, we have examined the role of TNF on neurons using the clonal murine neuroblastoma line, N1E-115 (N1E). N1E cells represent a well-defined model for studying neuronal development since they can be maintained as either undifferentiated, mitotically active neuroblasts or as differentiated, mature neurons. Northern and reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that both undifferentiated and differentiated N1Es express transcripts for the 55 kDa TNF receptor (TNFR), but not the 75 kDa TNFR. The biological activity of the expressed TNF receptor was demonstrated by a dose dependent cytotoxicity to either recombinant murine or human TNF when the cells were incubated with the transcriptional inhibitor actinomycin D. The lack of the 75 kDa receptor mRNA expression and the dose dependent response to rHuTNF, an agonist specific for the murine 55 kDa receptor, suggest that the TNF induced cytotoxicity is mediated through the 55 kDa receptor in both the undifferentiated and differentiated N1Es. Light microscopic observations, flow cytometric analysis of hypodiploid DNA, and electrophoretic analysis of nucleosomal DNA fragmentation of N1Es treated with actinomycin D and TNF revealed features characteristic of both necrotic and apoptotic cell death. These findings demonstrate that blast and mature N1E cells express the 55 kDa TNF receptor which is responsible for inducing both necrotic and apoptotic death in these cells. The observation that actinomycin D renders N1E cells susceptible to the cytotoxic effects of TNF indicates that a sensitization step, such as removal of an endogenous protective factor or viral-mediated inhibition of transcription, may be necessary for TNF cytotoxicity in neurons.

Differential immunomodulatory activity of tumor cell death induced by cancer therapeutic toll-like receptor ligands.

PubMed

Klein, Johanna C; Wild, Clarissa A; Lang, Stephan; Brandau, Sven

2016-06-01

Synthetic toll-like receptor (TLR) ligands stimulate defined immune cell subsets and are currently tested as novel immunotherapeutic agents against cancer with, however, varying clinical efficacy. Recent data showed the expression of TLR receptors also on tumor cells. In this study we investigated immunological events associated with the induction of tumor cell death by poly(I:C) and imiquimod. A human head and neck squamous cell carcinoma (HNSCC) cell line was exposed to poly(I:C) and imiquimod, which were delivered exogenously via culture medium or via electroporation. Cell death and cell biological consequences thereof were analyzed. For in vivo analyses, a human xenograft and a syngeneic immunocompetent mouse model were used. Poly(I:C) induced cell death only if delivered by electroporation into the cytosol. Cell death induced by poly(I:C) resulted in cytokine release and activation of monocytes in vitro. Monocytes activated by the supernatant of cancer cells previously exposed to poly(I:C) recruited significantly more Th1 cells than monocytes exposed to control supernatants. If delivered exogenously, imiquimod also induced tumor cell death and some release of interleukin-6, but cell death was not associated with release of Th1 cytokines, interferons, monocyte activation and Th1 recruitment. Interestingly, intratumoral injection of poly(I:C) triggered tumor cell death in tumor-bearing mice and reduced tumor growth independent of TLR signaling on host cells. Imiquimod did not affect tumor size. Our data suggest that common cancer therapeutic RNA compounds can induce functionally diverse types of cell death in tumor cells with implications for the use of TLR ligands in cancer immunotherapy.

Gefitinib enhances human colon cancer cells to TRAIL-induced apoptosis of via autophagy- and JNK-mediated death receptors upregulation.

PubMed

Chen, Lei; Meng, Yue; Guo, Xiaoqing; Sheng, Xiaotong; Tai, Guihua; Zhang, Fenglei; Cheng, Hairong; Zhou, Yifa

2016-11-01

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a potent cancer cell-specific apoptosis-inducing cytokine with little toxicity to most normal cells. Here, we report that gefitinib and TRAIL in combination produce a potent synergistic effect on TRAIL-sensitive human colon cancer HCT116 cells and an additive effect on TRAIL-resistant HT-29 cells. Interestingly, gefitinib increases the expression of cell surface receptors DR4 and DR5, possibly explaining the synergistic effect. Knockdown of DR4 and DR5 by siRNA significantly decreases gefitinib- and TRAIL-mediated cell apoptosis, supporting this idea. Because the inhibition of gefitinib-induced autophagy by 3-MA significantly decreases DR4 and DR5 upregulation, as well as reduces gefitinib- and TRAIL-induced apoptosis, we conclude that death receptor upregulation is autophagy mediated. Furthermore, our results indicate that death receptor expression may also be regulated by JNK activation, because pre-treatment of cells with JNK inhibitor SP600125 significantly decreases gefitinib-induced death receptor upregulation. Interestingly, SP600125 also inhibits the expression CHOP, yet CHOP has no impact on death receptor expressions. We also find here that phosphorylation of Akt and ERK might also be required for TRAIL sensitization. In summary, our results indicate that gefitinib effectively enhances TRAIL-induced apoptosis, likely via autophagy and JNK- mediated death receptor expression and phosphorylation of Akt and ERK.

The Sigma Receptor Ligand (+)-Pentazocine Prevents Apoptotic Retinal Ganglion Cell Death induced in vitro by Homocysteine and Glutamate

PubMed Central

Martin, Pamela Moore; Ola, Mohammad S.; Agarwal, Neeraj; Ganapathy, Vadivel; Smith, Sylvia B.

2013-01-01

Recent studies demonstrated that the excitotoxic amino acid homocysteine induces apoptotic death of retinal ganglion cells in vivo. In the present study, an in vitro rat retinal ganglion cell (RGC-5) culture system was used to analyze the toxicity of acute exposure to high levels of homocysteine, the mechanism of homocysteine-induced toxicity and the usefulness of σR1 ligands as neuroprotectants. When cultured RGC-5 cells were subjected to treatment with 1 mM D, L- homocysteine, a significant increase in cell death was detected by TUNEL analysis and analysis of activated caspase. When cells were treated with homocysteine- or glutamate in the presence of MK-801, an antagonist of the NMDA receptor, the cell death was inhibited significantly. In contrast, NBQX, an antagonist of the AMPA/Kainate receptor, and nifedipine, a calcium channel blocker, did not prevent the homocysteine- or glutamate-induced cell death. Semi-quantitative RT-PCR and immunocytochemical analysis demonstrated that RGC-5 cells exposed to homocysteine or glutamate express type 1 sigma receptor at levels similar to control cells. Treatment of RGC-5 cells with 3 µM or 10 µM concentrations of the σR1-specific ligand (+)-pentazocine inhibited significantly the apoptotic cell death induced by homocysteine or glutamate. The results suggest that homocysteine is toxic to ganglion cells in vitro, that the toxicity is mediated via NMDA receptor activation, and that the σR1-specific ligand (+)-pentazocine can block the RGC-5 cell death induced by homocysteine and glutamate. PMID:15046867

Poly(ADP-ribose) polymerase inhibitors sensitize cancer cells to death receptor-mediated apoptosis by enhancing death receptor expression.

PubMed

Meng, X Wei; Koh, Brian D; Zhang, Jin-San; Flatten, Karen S; Schneider, Paula A; Billadeau, Daniel D; Hess, Allan D; Smith, B Douglas; Karp, Judith E; Kaufmann, Scott H

2014-07-25

Recombinant human tumor necrosis factor-α-related apoptosis inducing ligand (TRAIL), agonistic monoclonal antibodies to TRAIL receptors, and small molecule TRAIL receptor agonists are in various stages of preclinical and early phase clinical testing as potential anticancer drugs. Accordingly, there is substantial interest in understanding factors that affect sensitivity to these agents. In the present study we observed that the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib and veliparib sensitize the myeloid leukemia cell lines ML-1 and K562, the ovarian cancer line PEO1, non-small cell lung cancer line A549, and a majority of clinical AML isolates, but not normal marrow, to TRAIL. Further analysis demonstrated that PARP inhibitor treatment results in activation of the FAS and TNFRSF10B (death receptor 5 (DR5)) promoters, increased Fas and DR5 mRNA, and elevated cell surface expression of these receptors in sensitized cells. Chromatin immunoprecipitation demonstrated enhanced binding of the transcription factor Sp1 to the TNFRSF10B promoter in the presence of PARP inhibitor. Knockdown of PARP1 or PARP2 (but not PARP3 and PARP4) not only increased expression of Fas and DR5 at the mRNA and protein level, but also recapitulated the sensitizing effects of the PARP inhibition. Conversely, Sp1 knockdown diminished the PARP inhibitor effects. In view of the fact that TRAIL is part of the armamentarium of natural killer cells, these observations identify a new facet of PARP inhibitor action while simultaneously providing the mechanistic underpinnings of a novel therapeutic combination that warrants further investigation.

Poly(ADP-ribose) Polymerase Inhibitors Sensitize Cancer Cells to Death Receptor-mediated Apoptosis by Enhancing Death Receptor Expression*

PubMed Central

Meng, X. Wei; Koh, Brian D.; Zhang, Jin-San; Flatten, Karen S.; Schneider, Paula A.; Billadeau, Daniel D.; Hess, Allan D.; Smith, B. Douglas; Karp, Judith E.; Kaufmann, Scott H.

2014-01-01

Recombinant human tumor necrosis factor-α-related apoptosis inducing ligand (TRAIL), agonistic monoclonal antibodies to TRAIL receptors, and small molecule TRAIL receptor agonists are in various stages of preclinical and early phase clinical testing as potential anticancer drugs. Accordingly, there is substantial interest in understanding factors that affect sensitivity to these agents. In the present study we observed that the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib and veliparib sensitize the myeloid leukemia cell lines ML-1 and K562, the ovarian cancer line PEO1, non-small cell lung cancer line A549, and a majority of clinical AML isolates, but not normal marrow, to TRAIL. Further analysis demonstrated that PARP inhibitor treatment results in activation of the FAS and TNFRSF10B (death receptor 5 (DR5)) promoters, increased Fas and DR5 mRNA, and elevated cell surface expression of these receptors in sensitized cells. Chromatin immunoprecipitation demonstrated enhanced binding of the transcription factor Sp1 to the TNFRSF10B promoter in the presence of PARP inhibitor. Knockdown of PARP1 or PARP2 (but not PARP3 and PARP4) not only increased expression of Fas and DR5 at the mRNA and protein level, but also recapitulated the sensitizing effects of the PARP inhibition. Conversely, Sp1 knockdown diminished the PARP inhibitor effects. In view of the fact that TRAIL is part of the armamentarium of natural killer cells, these observations identify a new facet of PARP inhibitor action while simultaneously providing the mechanistic underpinnings of a novel therapeutic combination that warrants further investigation. PMID:24895135

Influence of Berry-Polyphenols on Receptor Signaling and Cell-Death Pathways: Implications for Breast Cancer Prevention

PubMed Central

Aiyer, Harini S; Warri, Anni M; Woode, Denzel R; Hilakivi-Clarke, Leena; Clarke, Robert

2012-01-01

Breast cancer is the most commonly diagnosed cancer among women worldwide. Many women have become more aware of the benefits of increasing fruit consumption, as part of a healthy lifestyle, for the prevention of cancer. The mechanisms by which fruits, including berries, prevent breast cancer can be partially explained by exploring their interactions with pathways known influence cell-proliferation and evasion of cell-death. Two receptor pathways- estrogen receptor (ER) and tyrosine kinase receptors, especially the epidermal growth factor receptor (EGFR) family- are drivers of cell-proliferation and play a significant role in the development of both primary and recurrent breast cancer. There is strong evidence to show that several phytochemicals present in berries such as cyanidin, delphinidin, quercetin, kaempferol, ellagic acid, resveratrol and pterostilbene, interact with and alter the effects of these pathways. Further, they also induce cell death (apoptosis and autophagy) via their influence on kinase signaling. In this review, we summarize in vitro data regarding the interaction of berry polyphenols with the specific receptors and the mechanisms by which they induce cell death. Further, we also present in vivo data of primary breast cancer prevention by individual compounds and whole berries. Finally, we present a possible role for berries and berry compounds in the prevention of breast cancer and our perspective on the areas that require further research. PMID:22300613

Activation of aryl hydrocarbon receptor reduces carbendazim-induced cell death

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Kuo-Liang

Carbendazim inhibits microtubule assembly, thus blocking mitosis and inhibiting cancer cell proliferation. Accordingly, carbendazim is being explored as an anticancer drug. Data show that carbendazim increased mRNA and protein expressions and promoter activity of CYP1A1. In addition, carbendazim activated transcriptional activity of the aryl hydrocarbon response element, and induced nuclear translocation of the aryl hydrocarbon receptor (AhR), a sign the AhR is activated. Carbendazim-induced CYP1A1 expression was blocked by AhR antagonists, and was abolished in AhR signal-deficient cells. Results demonstrated that carbendazim activated the AhR, thereby stimulating CYP1A1 expression. In order to understand whether AhR-induced metabolic enzymes turn carbendazim intomore » less-toxic metabolites, Hoechst 33342 staining to reveal carbendazim-induced nuclear changes and flow cytometry to reveal the subG{sub 0}/G{sub 1} population were applied to monitor carbendazim-induced cell apoptosis. Carbendazim induced less apoptosis in Hepa-1c1c7 cells than in AhR signal-deficient Hepa-1c1c7 mutant cells. Pretreatment with β-NF, an AhR agonist that highly induces CYP1A1 expression, decreased carbendazim-induced cell death. In addition, the lower the level of AhR was, the lower the vitality present in carbendazim-treated cells, including hepatoma cells and their derivatives with AhR RNA interference, also embryonic kidney cells, bladder carcinoma cells, and AhR signal-deficient Hepa-1c1c7 cells. In summary, carbendazim is an AhR agonist. The toxicity of carbendazim was lower in cells with the AhR signal. This report provides clues indicating that carbendazim is more potent at inducing cell death in tissues without than in those with the AhR signal, an important reference for applying carbendazim in cancer chemotherapy. - Highlights: • Carbendazim induced transcriptional activity of the aryl hydrocarbon response element. • Carbendazim induced nuclear translocation of the

GRIM REAPER peptide binds to receptor kinase PRK5 to trigger cell death in Arabidopsis

PubMed Central

Wrzaczek, Michael; Vainonen, Julia P; Stael, Simon; Tsiatsiani, Liana; Help-Rinta-Rahko, Hanna; Gauthier, Adrien; Kaufholdt, David; Bollhöner, Benjamin; Lamminmäki, Airi; Staes, An; Gevaert, Kris; Tuominen, Hannele; Van Breusegem, Frank; Helariutta, Ykä; Kangasjärvi, Jaakko

2015-01-01

Recognition of extracellular peptides by plasma membrane-localized receptor proteins is commonly used in signal transduction. In plants, very little is known about how extracellular peptides are processed and activated in order to allow recognition by receptors. Here, we show that induction of cell death in planta by a secreted plant protein GRIM REAPER (GRI) is dependent on the activity of the type II metacaspase METACASPASE-9. GRI is cleaved by METACASPASE-9 in vitro resulting in the release of an 11 amino acid peptide. This peptide bound in vivo to the extracellular domain of the plasma membrane-localized, atypical leucine-rich repeat receptor-like kinase POLLEN-SPECIFIC RECEPTOR-LIKE KINASE 5 (PRK5) and was sufficient to induce oxidative stress/ROS-dependent cell death. This shows a signaling pathway in plants from processing and activation of an extracellular protein to recognition by its receptor. PMID:25398910

GRIM REAPER peptide binds to receptor kinase PRK5 to trigger cell death in Arabidopsis.

PubMed

Wrzaczek, Michael; Vainonen, Julia P; Stael, Simon; Tsiatsiani, Liana; Help-Rinta-Rahko, Hanna; Gauthier, Adrien; Kaufholdt, David; Bollhöner, Benjamin; Lamminmäki, Airi; Staes, An; Gevaert, Kris; Tuominen, Hannele; Van Breusegem, Frank; Helariutta, Ykä; Kangasjärvi, Jaakko

2015-01-02

Recognition of extracellular peptides by plasma membrane-localized receptor proteins is commonly used in signal transduction. In plants, very little is known about how extracellular peptides are processed and activated in order to allow recognition by receptors. Here, we show that induction of cell death in planta by a secreted plant protein GRIM REAPER (GRI) is dependent on the activity of the type II metacaspase METACASPASE-9. GRI is cleaved by METACASPASE-9 in vitro resulting in the release of an 11 amino acid peptide. This peptide bound in vivo to the extracellular domain of the plasma membrane-localized, atypical leucine-rich repeat receptor-like kinase POLLEN-SPECIFIC RECEPTOR-LIKE KINASE 5 (PRK5) and was sufficient to induce oxidative stress/ROS-dependent cell death. This shows a signaling pathway in plants from processing and activation of an extracellular protein to recognition by its receptor. © 2014 The Authors.

Glucose Deprivation Induces ATF4-Mediated Apoptosis through TRAIL Death Receptors

PubMed Central

Iurlaro, Raffaella; Püschel, Franziska; León-Annicchiarico, Clara Lucía; O'Connor, Hazel; Martin, Seamus J.; Palou-Gramón, Daniel; Lucendo, Estefanía

2017-01-01

ABSTRACT Metabolic stress occurs frequently in tumors and in normal tissues undergoing transient ischemia. Nutrient deprivation triggers, among many potential cell death-inducing pathways, an endoplasmic reticulum (ER) stress response with the induction of the integrated stress response transcription factor ATF4. However, how this results in cell death remains unknown. Here we show that glucose deprivation triggered ER stress and induced the unfolded protein response transcription factors ATF4 and CHOP. This was associated with the nontranscriptional accumulation of TRAIL receptor 1 (TRAIL-R1) (DR4) and with the ATF4-mediated, CHOP-independent induction of TRAIL-R2 (DR5), suggesting that cell death in this context may involve death receptor signaling. Consistent with this, the ablation of TRAIL-R1, TRAIL-R2, FADD, Bid, and caspase-8 attenuated cell death, although the downregulation of TRAIL did not, suggesting ligand-independent activation of TRAIL receptors. These data indicate that stress triggered by glucose deprivation promotes the ATF4-dependent upregulation of TRAIL-R2/DR5 and TRAIL receptor-mediated cell death. PMID:28242652

A novel Arabidopsis CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) mutant with enhanced pathogen-induced cell death and altered receptor processing.

PubMed

Petutschnig, Elena K; Stolze, Marnie; Lipka, Ulrike; Kopischke, Michaela; Horlacher, Juliane; Valerius, Oliver; Rozhon, Wilfried; Gust, Andrea A; Kemmerling, Birgit; Poppenberger, Brigitte; Braus, Gerhard H; Nürnberger, Thorsten; Lipka, Volker

2014-12-01

Plants detect pathogens by sensing microbe-associated molecular patterns (MAMPs) through pattern recognition receptors. Pattern recognition receptor complexes also have roles in cell death control, but the underlying mechanisms are poorly understood. Here, we report isolation of cerk1-4, a novel mutant allele of the Arabidopsis chitin receptor CERK1 with enhanced defense responses. We identified cerk1-4 in a forward genetic screen with barley powdery mildew and consequently characterized it by pathogen assays, mutant crosses and analysis of defense pathways. CERK1 and CERK1-4 proteins were analyzed biochemically. The cerk1-4 mutation causes an amino acid exchange in the CERK1 ectodomain. Mutant plants maintain chitin signaling capacity but exhibit hyper-inducible salicylic acid concentrations and deregulated cell death upon pathogen challenge. In contrast to chitin signaling, the cerk1-4 phenotype does not require kinase activity and is conferred by the N-terminal part of the receptor. CERK1 undergoes ectodomain shedding, a well-known process in animal cell surface proteins. Wild-type plants contain the full-length CERK1 receptor protein as well as a soluble form of the CERK1 ectodomain, whereas cerk1-4 plants lack the N-terminal shedding product. Our work suggests that CERK1 may have a chitin-independent role in cell death control and is the first report of ectodomain shedding in plants. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

The Fas/CD95 Receptor Regulates the Death of Autoreactive B Cells and the Selection of Antigen-Specific B Cells

PubMed Central

Koncz, Gabor; Hueber, Anne-Odile

2012-01-01

Cell death receptors have crucial roles in the regulation of immune responses. Here we review recent in vivo data confirming that the Fas death receptor (TNFSR6) on B cells is important for the regulation of autoimmunity since the impairment of only Fas function on B cells results in uncontrolled autoantibody production and autoimmunity. Fas plays a role in the elimination of the non-specific and autoreactive B cells in germinal center, while during the selection of antigen-specific B cells different escape signals ensure the resistance to Fas-mediated apoptosis. Antigen-specific survival such as BCR or MHCII signal or coreceptors (CD19) cooperating with BCR inhibits the formation of death inducing signaling complex. Antigen-specific survival can be reinforced by antigen-independent signals of IL-4 or CD40 overproducing the anti-apoptotic members of the Bcl-2 family proteins. PMID:22848207

Death receptor-independent FADD signalling triggers hepatitis and hepatocellular carcinoma in mice with liver parenchymal cell-specific NEMO knockout.

PubMed

Ehlken, H; Krishna-Subramanian, S; Ochoa-Callejero, L; Kondylis, V; Nadi, N E; Straub, B K; Schirmacher, P; Walczak, H; Kollias, G; Pasparakis, M

2014-11-01

Hepatocellular carcinoma (HCC) usually develops in the context of chronic hepatitis triggered by viruses or toxic substances causing hepatocyte death, inflammation and compensatory proliferation of liver cells. Death receptors of the TNFR superfamily regulate cell death and inflammation and are implicated in liver disease and cancer. Liver parenchymal cell-specific ablation of NEMO/IKKγ, a subunit of the IκB kinase (IKK) complex that is essential for the activation of canonical NF-κB signalling, sensitized hepatocytes to apoptosis and caused the spontaneous development of chronic hepatitis and HCC in mice. Here we show that hepatitis and HCC development in NEMO(LPC-KO) mice is triggered by death receptor-independent FADD-mediated hepatocyte apoptosis. TNF deficiency in all cells or conditional LPC-specific ablation of TNFR1, Fas or TRAIL-R did not prevent hepatocyte apoptosis, hepatitis and HCC development in NEMO(LPC-KO) mice. To address potential functional redundancies between death receptors we generated and analysed NEMO(LPC-KO) mice with combined LPC-specific deficiency of TNFR1, Fas and TRAIL-R and found that also simultaneous lack of all three death receptors did not prevent hepatocyte apoptosis, chronic hepatitis and HCC development. However, LPC-specific combined deficiency in TNFR1, Fas and TRAIL-R protected the NEMO-deficient liver from LPS-induced liver failure, showing that different mechanisms trigger spontaneous and LPS-induced hepatocyte apoptosis in NEMO(LPC-KO) mice. In addition, NK cell depletion did not prevent liver damage and hepatitis. Moreover, NEMO(LPC-KO) mice crossed into a RAG-1-deficient genetic background-developed hepatitis and HCC. Collectively, these results show that the spontaneous development of hepatocyte apoptosis, chronic hepatitis and HCC in NEMO(LPC-KO) mice occurs independently of death receptor signalling, NK cells and B and T lymphocytes, arguing against an immunological trigger as the critical stimulus driving

Endoplasmic reticulum-resident E3 ubiquitin ligase Hrd1 controls B-cell immunity through degradation of the death receptor CD95/Fas

PubMed Central

Kong, Sinyi; Yang, Yi; Xu, Yuanming; Wang, Yajun; Zhang, Yusi; Melo-Cardenas, Johanna; Xu, Xiangping; Gao, Beixue; Thorp, Edward B.; Zhang, Donna D.; Zhang, Bin; Song, Jianxun; Zhang, Kezhong; Zhang, Jianning; Zhang, Jinping; Li, Huabin; Fang, Deyu

2016-01-01

Humoral immunity involves multiple checkpoints during B-cell development, maturation, and activation. The cell death receptor CD95/Fas-mediated apoptosis plays a critical role in eliminating the unwanted activation of B cells by self-reactive antigens and in maintaining B-cell homeostasis through activation-induced B-cell death (AICD). The molecular mechanisms controlling AICD remain largely undefined. Herein, we show that the E3 ubiquitin ligase Hrd1 protected B cells from activation-induced cell death by degrading the death receptor Fas. Hrd1-null B cells exhibited high Fas expression during activation and rapidly underwent Fas-mediated apoptosis, which could be largely inhibited by FasL neutralization. Fas mutation in Hrd1 KO mice abrogated the increase in B-cell AICD. We identified Hrd1 as the first E3 ubiquitin ligase of the death receptor Fas and Hrd1-mediated Fas destruction as a molecular mechanism in regulating B-cell immunity. PMID:27573825

Endoplasmic reticulum-resident E3 ubiquitin ligase Hrd1 controls B-cell immunity through degradation of the death receptor CD95/Fas.

PubMed

Kong, Sinyi; Yang, Yi; Xu, Yuanming; Wang, Yajun; Zhang, Yusi; Melo-Cardenas, Johanna; Xu, Xiangping; Gao, Beixue; Thorp, Edward B; Zhang, Donna D; Zhang, Bin; Song, Jianxun; Zhang, Kezhong; Zhang, Jianning; Zhang, Jinping; Li, Huabin; Fang, Deyu

2016-09-13

Humoral immunity involves multiple checkpoints during B-cell development, maturation, and activation. The cell death receptor CD95/Fas-mediated apoptosis plays a critical role in eliminating the unwanted activation of B cells by self-reactive antigens and in maintaining B-cell homeostasis through activation-induced B-cell death (AICD). The molecular mechanisms controlling AICD remain largely undefined. Herein, we show that the E3 ubiquitin ligase Hrd1 protected B cells from activation-induced cell death by degrading the death receptor Fas. Hrd1-null B cells exhibited high Fas expression during activation and rapidly underwent Fas-mediated apoptosis, which could be largely inhibited by FasL neutralization. Fas mutation in Hrd1 KO mice abrogated the increase in B-cell AICD. We identified Hrd1 as the first E3 ubiquitin ligase of the death receptor Fas and Hrd1-mediated Fas destruction as a molecular mechanism in regulating B-cell immunity.

TRAIL Death Receptor-4, Decoy Receptor-1 and Decoy Receptor-2 Expression on CD8+ T Cells Correlate with the Disease Severity in Patients with Rheumatoid Arthritis

PubMed Central

2010-01-01

Background Rheumatoid Arthritis (RA) is a chronic autoimmune inflammatory disorder. Although the pathogenesis of disease is unclear, it is well known that T cells play a major role in both development and perpetuation of RA through activating macrophages and B cells. Since the lack of TNF-Related Apoptosis Inducing Ligand (TRAIL) expression resulted in defective thymocyte apoptosis leading to an autoimmune disease, we explored evidence for alterations in TRAIL/TRAIL receptor expression on peripheral T lymphocytes in the molecular mechanism of RA development. Methods The expression of TRAIL/TRAIL receptors on T cells in 20 RA patients and 12 control individuals were analyzed using flow cytometry. The correlation of TRAIL and its receptor expression profile was compared with clinical RA parameters (RA activity scored as per DAS28) using Spearman Rho Analysis. Results While no change was detected in the ratio of CD4+ to CD8+ T cells between controls and RA patient groups, upregulation of TRAIL and its receptors (both death and decoy) was detected on both CD4+ and CD8+ T cells in RA patients compared to control individuals. Death Receptor-4 (DR4) and the decoy receptors DcR1 and DcR2 on CD8+ T cells, but not on CD4+ T cells, were positively correlated with patients' DAS scores. Conclusions Our data suggest that TRAIL/TRAIL receptor expression profiles on T cells might be important in revelation of RA pathogenesis. PMID:20799941

Senescent cells re-engineered to express soluble programmed death receptor-1 for inhibiting programmed death receptor-1/programmed death ligand-1 as a vaccination approach against breast cancer.

PubMed

Chen, Zehong; Hu, Kang; Feng, Lieting; Su, Ruxiong; Lai, Nan; Yang, Zike; Kang, Shijun

2018-06-01

Various types of vaccines have been proposed as approaches for prevention or delay of the onset of cancer by boosting the endogenous immune system. We previously developed a senescent-cell-based vaccine, induced by radiation and veliparib, as a preventive and therapeutic tool against triple-negative breast cancer. However, the programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1) pathway was found to play an important role in vaccine failure. Hence, we further developed soluble programmed death receptor-1 (sPD1)-expressing senescent cells to overcome PD-L1/PD-1-mediated immune suppression while vaccinating to promote dendritic cell (DC) maturity, thereby amplifying T-cell activation. In the present study, sPD1-expressing senescent cells showed a particularly active status characterized by growth arrest and modified immunostimulatory cytokine secretion in vitro. As expected, sPD1-expressing senescent tumor cell vaccine (STCV/sPD-1) treatment attracted more mature DC and fewer exhausted-PD1 + T cells in vivo. During the course of the vaccine studies, we observed greater safety and efficacy for STCV/sPD-1 than for control treatments. STCV/sPD-1 pre-injections provided complete protection from 4T1 tumor challenge in mice. Additionally, the in vivo therapeutic study of mice with s.c. 4T1 tumor showed that STCV/sPD-1 vaccination delayed tumorigenesis and suppressed tumor progression at early stages. These results showed that STCV/sPD-1 effectively induced a strong antitumor immune response against cancer and suggested that it might be a potential strategy for TNBC prevention. © 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Cigarette smoke-induced cell death of a spermatocyte cell line can be prevented by inactivating the Aryl hydrocarbon receptor

PubMed Central

Esakky, P; Hansen, D A; Drury, A M; Cusumano, A; Moley, K H

2015-01-01

Cigarette smoke exposure causes germ cell death during spermatogenesis. Our earlier studies demonstrated that cigarette smoke condensate (CSC) causes spermatocyte cell death in vivo and growth arrest of the mouse spermatocyte cell line (GC-2spd(ts)) in vitro via the aryl hydrocarbon receptor (AHR). We hypothesize here that inactivation of AHR could prevent the CSC-induced cell death in spermatocytes. We demonstrate that CSC exposure generates oxidative stress, which differentially regulates mitochondrial apoptosis in GC-2spd(ts) and wild type (WT) and AHR knockout (AHR-KO) mouse embryonic fibroblasts (MEFs). SiRNA-mediated silencing of Ahr augments the extent of CSC-mediated cellular damage while complementing the AHR-knockout condition. Pharmacological inhibition using the AHR-antagonist (CH223191) modulates the CSC-altered expression of apoptotic proteins and significantly abrogates DNA fragmentation though the cleavage of PARP appears AHR independent. Pretreatment with CH223191 at concentrations above 50 μM significantly prevents the CSC-induced activation of caspase-3/7 and externalization of phosphatidylserine in the plasma membrane. However, MAPK inhibitors alone or together with CH223191 could not prevent the membrane damage upon CSC addition and the caspase-3/7 activation and membrane damage in AHR-deficient MEF indicates the interplay of multiple cell signaling and cytoprotective ability of AHR. Thus the data obtained on one hand signifies the protective role of AHR in maintaining normal cellular homeostasis and the other, could be a potential prophylactic therapeutic target to promote cell survival and growth under cigarette smoke exposed environment by receptor antagonism via CH223191-like mechanism. Antagonist-mediated inactivation of the aryl hydrocarbon receptor blocks downstream events leading to cigarette smoke-induced cell death of a spermatocyte cell line. PMID:27551479

Death Receptor-Induced Apoptosis Signalling Regulation by Ezrin Is Cell Type Dependent and Occurs in a DISC-Independent Manner in Colon Cancer Cells

PubMed Central

Iessi, Elisabetta; Zischler, Luciana; Etringer, Aurélie; Bergeret, Marion; Morlé, Aymeric; Jacquemin, Guillaume; Morizot, Alexandre; Shirley, Sarah; Lalaoui, Najoua; Elifio-Esposito, Selene L.; Fais, Stefano; Garrido, Carmen; Solary, Eric; Micheau, Olivier

2015-01-01

Ezrin belongs to the ERM (ezrin-radixin-moesin) protein family and has been demonstrated to regulate early steps of Fas receptor signalling in lymphoid cells, but its contribution to TRAIL-induced cell death regulation in adherent cancer cells remains unknown. In this study we report that regulation of FasL and TRAIL-induced cell death by ezrin is cell type dependant. Ezrin is a positive regulator of apoptosis in T-lymphoma cell line Jurkat, but a negative regulator in colon cancer cells. Using ezrin phosphorylation or actin-binding mutants, we provide evidence that negative regulation of death receptor-induced apoptosis by ezrin occurs in a cytoskeleton- and DISC-independent manner, in colon cancer cells. Remarkably, inhibition of apoptosis induced by these ligands was found to be tightly associated with regulation of ezrin phosphorylation on serine 66, the tumor suppressor gene WWOX and activation of PKA. Deficiency in WWOX expression in the liver cancer SK-HEP1 or the pancreatic Mia PaCa-2 cell lines as well as WWOX silencing or modulation of PKA activation by pharmacological regulators, in the colon cancer cell line SW480, abrogated regulation of TRAIL signalling by ezrin. Altogether our results show that death receptor pro-apoptotic signalling regulation by ezrin can occur downstream of the DISC in colon cancer cells. PMID:26010871

Oncolytic vesicular stomatitis virus induces apoptosis in U87 glioblastoma cells by a type II death receptor mechanism and induces cell death and tumor clearance in vivo.

PubMed

Cary, Zachary D; Willingham, Mark C; Lyles, Douglas S

2011-06-01

Vesicular stomatitis virus (VSV) is a potential oncolytic virus for treating glioblastoma multiforme (GBM), an aggressive brain tumor. Matrix (M) protein mutants of VSV have shown greater selectivity for killing GBM cells versus normal brain cells than VSV with wild-type M protein. The goal of this research was to determine the contribution of death receptor and mitochondrial pathways to apoptosis induced by an M protein mutant (M51R) VSV in U87 human GBM tumor cells. Compared to controls, U87 cells expressing a dominant negative form of Fas (dnFas) or overexpressing Bcl-X(L) had reduced caspase-3 activation following infection with M51R VSV, indicating that both the death receptor pathway and mitochondrial pathways are important for M51R VSV-induced apoptosis. Death receptor signaling has been classified as type I or type II, depending on whether signaling is independent (type I) or dependent on the mitochondrial pathway (type II). Bcl-X(L) overexpression inhibited caspase activation in response to a Fas-inducing antibody, similar to the inhibition in response to M51R VSV infection, indicating that U87 cells behave as type II cells. Inhibition of apoptosis in vitro delayed, but did not prevent, virus-induced cell death. Murine xenografts of U87 cells that overexpress Bcl-X(L) regressed with a time course similar to that of control cells following treatment with M51R VSV, and tumors were not detectable at 21 days postinoculation. Immunohistochemical analysis demonstrated similar levels of viral antigen expression but reduced activation of caspase-3 following virus treatment of Bcl-X(L)-overexpressing tumors compared to controls. Further, the pathological changes in tumors following treatment with virus were quite different in the presence versus the absence of Bcl-X(L) overexpression. These results demonstrate that M51R VSV efficiently induces oncolysis in GBM tumor cells despite deregulation of apoptotic pathways, underscoring its potential use as a treatment for

Immunotherapy targeting folate receptor induces cell death associated with autophagy in ovarian cancer

PubMed Central

Wen, Yunfei; Graybill, Whitney S.; Previs, Rebecca A.; Hu, Wei; Ivan, Cristina; Mangala, Lingegowda S.; Zand, Behrouz; Nick, Alpa M.; Jennings, Nicholas B.; Dalton, Heather J.; Sehgal, Vasudha; Ram, Prahlad; Lee, Ju-Seog; Vivas-Mejia, Pablo E.; Coleman, Robert L.; Sood, Anil K.

2014-01-01

Purpose Cancer cells are highly dependent on folate metabolism, making them susceptible to drugs that inhibit folate receptor activities. Targeting overexpressed folate receptor alpha (FRα) in cancer cells offers a therapeutic opportunity. We investigated the functional mechanisms of MORAB-003 (farletuzumab), a humanized monoclonal antibody against FRα, in ovarian cancer models. Experimental Design We first examined FRα expression in an array of human ovarian cancer cell lines and then assessed the in vivo effect of MORAB-003 on tumor growth and progression in several orthotopic mouse models of ovarian cancer derived from these cell lines. Molecular mechanisms of tumor cell death induced by MORAB-003 were investigated by cDNA and protein expression profiling analysis. Mechanistic studies were performed to determine the role of autophagy in MORAB-003–induced cell death. Results MORAB-003 significantly decreased tumor growth in the high-FRα IGROV1 and SKOV3ip1 models but not in the low-FRα A2780 model. MORAB-003 reduced proliferation but had no significant effect on apoptosis. Protein expression and cDNA microarray analyses showed that MORAB-003 regulated an array of autophagy-related genes. It also significantly increased expression of LC3 isoform II and enriched autophagic vacuolization. Blocking autophagy with hydroxychloroquine or bafilomycin A1 reversed the growth inhibition induced by MORAB-003. In add, alteration of FOLR1 gene copy number significantly correlated with shorter disease-free survival in patients with ovarian serous cystadenocarcinoma. Conclusions MORAB-003 displays prominent antitumor activity in ovarian cancer models expressing FRα at high levels. Blockade of folate receptor by MORAB-003 induced sustained autophagy and suppressed cell proliferation. PMID:25416196

Meconium increases type 1 angiotensin II receptor expression and alveolar cell death.

PubMed

Rosenfeld, Charles R; Zagariya, Alexander M; Liu, Xiao-Tie; Willis, Brigham C; Fluharty, Steven; Vidyasagar, Dharmapuri

2008-03-01

The pulmonary renin-angiotensin system (RAS) contributes to inflammation and epithelial apoptosis in meconium aspiration. It is unclear if both angiotensin II receptors (ATR) contribute, where they are expressed and if meconium modifies subtype expression. We examined ATR subtypes in 2 wk rabbit pup lungs before and after meconium exposure and with and without captopril pretreatment or type 1 receptor (AT1R) inhibition with losartan, determining expression and cellular localization with immunoblots, RT-PCR and immunohistochemistry, respectively. Responses of cultured rat alveolar type II pneumocytes were also examined. Type 2 ATR were undetected in newborn lung before and after meconium instillation. AT1R were expressed in pulmonary vascular and bronchial smooth muscle and alveolar and bronchial epithelium. Meconium increased total lung AT1R protein approximately 3-fold (p = 0.006), mRNA 29% (p = 0.006) and immunostaining in bronchial and alveolar epithelium and smooth muscle, which were unaffected by captopril and losartan. Meconium also increased AT1R expression >3-fold in cultured type II pneumocytes and caused concentration-dependent cell death inhibited by losartan. Meconium increases AT1R expression in newborn rabbit lung and cultured type II pneumocytes and induces AT1R-mediated cell death. The pulmonary RAS contributes to the pathogenesis of meconium aspiration through increased receptor expression.

Tyrosine kinase receptor EGFR regulates the switch in cancer cells between cell survival and cell death induced by autophagy in hypoxia.

PubMed

Chen, Yongqiang; Henson, Elizabeth S; Xiao, Wenyan; Huang, Daniel; McMillan-Ward, Eileen M; Israels, Sara J; Gibson, Spencer B

2016-06-02

Autophagy is an intracellular lysosomal degradation pathway where its primary function is to allow cells to survive under stressful conditions. Autophagy is, however, a double-edge sword that can either promote cell survival or cell death. In cancer, hypoxic regions contribute to poor prognosis due to the ability of cancer cells to adapt to hypoxia in part through autophagy. In contrast, autophagy could contribute to hypoxia induced cell death in cancer cells. In this study, we showed that autophagy increased during hypoxia. At 4 h of hypoxia, autophagy promoted cell survival whereas, after 48 h of hypoxia, autophagy increased cell death. Furthermore, we found that the tyrosine phosphorylation of EGFR (epidermal growth factor receptor) decreased after 16 h in hypoxia. Furthermore, EGFR binding to BECN1 in hypoxia was significantly higher at 4 h compared to 72 h. Knocking down or inhibiting EGFR resulted in an increase in autophagy contributing to increased cell death under hypoxia. In contrast, when EGFR was reactivated by the addition of EGF, the level of autophagy was reduced which led to decreased cell death. Hypoxia led to autophagic degradation of the lipid raft protein CAV1 (caveolin 1) that is known to bind and activate EGFR in a ligand-independent manner during hypoxia. By knocking down CAV1, the amount of EGFR phosphorylation was decreased in hypoxia and amount of autophagy and cell death increased. This indicates that the activation of EGFR plays a critical role in the switch between cell survival and cell death induced by autophagy in hypoxia.

Neuroprotective effect against axonal damage-induced retinal ganglion cell death in apolipoprotein E-deficient mice through the suppression of kainate receptor signaling.

PubMed

Omodaka, Kazuko; Nishiguchi, Koji M; Yasuda, Masayuki; Tanaka, Yuji; Sato, Kota; Nakamura, Orie; Maruyama, Kazuichi; Nakazawa, Toru

2014-10-24

Apolipoprotein E (ApoE) plays important roles in the body, including a carrier of cholesterols, an anti-oxidant, and a ligand for the low-density lipoprotein receptors. In the nervous system, the presence of ApoE4 isoforms is associated with Alzheimer's disease. ApoE gene polymorphisms are also associated with glaucoma, but the function of ApoE in the retina remains unclear. In this study, we investigated the role of ApoE in axonal damage-induced RGC death. ApoE was detected in the astrocytes and Müller cells in the wild-type (WT) retina. RGC damage was induced in adult ApoE-deficient mice (male, 10-12 weeks old) through ocular hypertension (OH), optic nerve crush (NC), or by administering kainic acid (KA) intravitreally. The WT mice were treated with a glutamate receptor antagonist (MK801 or CNQX) 30 min before performing NC or left untreated. Seven days later, the retinas were flat mounted and Fluorogold-labeled RGCs were counted. We found that the RGCs in the ApoE-deficient mice were resistant to OH-induced RGC death and optic nerve degeneration 4 weeks after induction. In WT mice, NC effectively induced RGC death (control: 4085±331 cells/mm(2), NC: 1728±170 cells/mm(2)). CNQX, an inhibitor of KA receptors, suppressed this RGC death (3031±246 cells/mm(2)), but MK801, an inhibitor of NMDA receptors, did not (1769±212 cells/mm(2)). This indicated the involvement of KA receptor signaling in NC-induced RGC death. We found that NC- or KA-induced RGC death was significantly less in the ApoE-deficient mice than in the WT mice. These data suggest that the ApoE deficiency had a neuroprotective effect against axonal damage-induced RGC death by suppressing the KA receptor signaling. Copyright © 2014 Elsevier B.V. All rights reserved.

Cannabinoid-induced cell death in endometrial cancer cells: involvement of TRPV1 receptors in apoptosis.

PubMed

Fonseca, B M; Correia-da-Silva, G; Teixeira, N A

2018-05-01

Among a variety of phytocannabinoids, Δ 9 -tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most promising therapeutic compounds. Besides the well-known palliative effects in cancer patients, cannabinoids have been shown to inhibit in vitro growth of tumor cells. Likewise, the major endocannabinoids (eCBs), anandamide (AEA) and 2-arachidonoylglycerol (2-AG), induce tumor cell death. The purpose of the present study was to characterize cannabinoid elements and evaluate the effect of cannabinoids in endometrial cancer cell viability. The presence of cannabinoid receptors, transient receptor potential vanilloid 1 (TRPV1), and endocannabinoid-metabolizing enzymes were determined by qRT-PCR and Western blot. We also examined the effects and the underlying mechanisms induced by eCBs and phytocannabinoids in endometrial cancer cell viability. Besides TRPV1, both EC cell lines express all the constituents of the endocannabinoid system. We observed that at concentrations higher than 5 μM, eCBs and CBD induced a significant reduction in cell viability in both Ishikawa and Hec50co cells, whereas THC did not cause any effect. In Ishikawa cells, contrary to Hec50co, treatment with AEA and CBD resulted in an increase in the levels of activated caspase -3/-7, in cleaved PARP, and in reactive oxygen species generation, confirming that the reduction in cell viability observed in the MTT assay was caused by the activation of the apoptotic pathway. Finally, these effects were dependent on TRPV1 activation and intracellular calcium levels. These data indicate that cannabinoids modulate endometrial cancer cell death. Selective targeting of TPRV1 by AEA, CBD, or other stable analogues may be an attractive research area for the treatment of estrogen-dependent endometrial carcinoma. Our data further support the evaluation of CBD and CBD-rich extracts for the potential treatment of endometrial cancer, particularly, that has become non-responsive to common therapies.

The machinery of Nod-like receptors: refining the paths to immunity and cell death.

PubMed

Saleh, Maya

2011-09-01

One of the fundamental aspects of the innate immune system is its capacity to discriminate between self and non-self or altered self, and to quickly respond by eliciting effector mechanisms that act in concert to restore normalcy. This capacity is determined by a set of evolutionarily conserved pattern recognition receptors (PRRs) that sense the presence of microbial motifs or endogenous danger signals, including tissue damage, cellular transformation or metabolic perturbation, and orchestrate the nature, duration and intensity of the innate immune response. Nod-like receptors (NLRs), a group of intracellular PRRs, are particularly essential as evident by the high incidence of genetic variations in their genes in various diseases of homeostasis. Here, I overview the signaling mechanisms of NLRs and discuss the mounting evidence of evolutionary conservation between their pathways and the cell death machinery. I also describe their effector functions that link the sensing of danger to the induction of inflammation, autophagy or cell death. © 2011 John Wiley & Sons A/S.

Sigma-2 ligands and PARP inhibitors synergistically trigger cell death in breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDonald, Elizabeth S.; Mankoff, Julia; Makvandi, Mehran

The sigma-2 receptor is overexpressed in proliferating cells compared to quiescent cells and has been used as a target for imaging solid tumors by positron emission tomography. Recent work has suggested that the sigma-2 receptor may also be an effective therapeutic target for cancer therapy. Poly (ADP-ribose) polymerase (PARP) is a family of enzymes involved in DNA damage response. In this study, we looked for potential synergy of cytotoxicity between PARP inhibitors and sigma-2 receptor ligands in breast cancer cell lines. We showed that the PARP inhibitor, YUN3-6, sensitized mouse breast cancer cell line, EMT6, to sigma-2 receptor ligand (SV119,more » WC-26, and RHM-138) induced cell death determined by cell viability assay and colony forming assay. The PARP inhibitor, olaparib, sensitized tumor cells to a different sigma-2 receptor ligand SW43-induced apoptosis and cell death in human triple negative cell line, MDA-MB-231. Olaparib inhibited PARP activity and cell proliferation, and arrested cells in G2/M phase of the cell cycle in MDA-MB-231 cells. Subsequently cells became sensitized to SW43 induced cell death. In conclusion, the combination of sigma-2 receptor ligands and PARP inhibitors appears to hold promise for synergistically triggering cell death in certain types of breast cancer cells and merits further investigation. - Highlights: • PARPi, YUN3-6 and olaparib, and σ2 ligands, SV119 and SW43, were evaluated. • Mouse and human breast cancer cells, EMT6 and MDA-MB-231 respectively, were used. • YUN3-6 and SV119 synergistically triggered cell death in EMT6 cells. • Olaparib and SW43 additively triggered cell death in MDA-MB-231 cells. • Olaparib arrested cells in G2/M in MDA-MB-231 cells.« less

Activation of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}) induces cell death through MAPK-dependent mechanism in osteoblastic cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Sung Hun; Yoo, Chong Il; Medical Research Institute, College of Medicine, Pusan National University, Pusan, 602-739

2006-09-01

The present study was undertaken to determine the role of the mitogen-activated protein kinase (MAPK) subfamilies in cell death induced by PPAR{gamma} agonists in osteoblastic cells. Ciglitazone and troglitazone, PPAR{gamma} agonists, resulted in a concentration- and time-dependent cell death, which was largely attributed to apoptosis. But a PPAR{alpha} agonist ciprofibrate did not affect the cell death. Ciglitazone caused reactive oxygen species (ROS) generation and ciglitazone-induced cell death was prevented by antioxidants, suggesting an important role of ROS generation in the ciglitazone-induced cell death. ROS generation and cell death induced by ciglitazone were inhibited by the PPAR{gamma} antagonist GW9662. Ciglitazone treatmentmore » caused activation of extracellular signal-regulated kinase (ERK) and p38. Activation of ERK was dependent on epidermal growth factor receptor (EGFR) and that of p38 was independent. Ciglitazone-induced cell death was significantly prevented by PD98059, an inhibitor of ERK upstream kinase MEK1/2, and SB203580, a p38 inhibitor. Ciglitazone treatment increased Bax expression and caused a loss of mitochondrial membrane potential, and its effect was prevented by N-acetylcysteine, PD98059, and SB203580. Ciglitazone induced caspase activation, which was prevented by PD98059 and SB203580. The general caspase inhibitor z-DEVD-FMK and the specific inhibitor of caspases-3 DEVD-CHO exerted the protective effect against the ciglitazone-induced cell death. The EGFR inhibitors AG1478 and suramin protected against the ciglitazone-induced cell death. Taken together, these findings suggest that the MAPK signaling pathways play an active role in mediating the ciglitazone-induced cell death of osteoblasts and function upstream of a mitochondria-dependent mechanism. These data may provide a novel insight into potential therapeutic strategies for treatment of osteoporosis.« less

Absence of Toll-like receptor 4 signaling results in delayed Yersinia enterocolitica YopP-induced cell death of dendritic cells.

PubMed

Gröbner, Sabine; Schulz, Sebastian; Soldanova, Irena; Gunst, Dani S J; Waibel, Michaela; Wesselborg, Sebastian; Borgmann, Stefan; Autenrieth, Ingo B

2007-01-01

In an initial period (< or =4 h) Toll-like receptor 4 (TLR4) signaling is required for Yersinia enterocolitica YopP-induced dendritic cell (DC) death. Later (>4 h), DC die independent of TLR4 signaling. In TLR4-deficient DC caspase 8 cleavage is delayed, indicating that TLR4 signaling accelerates caspase 8 activation, leading to DC death.

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

PubMed

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

2018-01-01

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

Angiotensin II attenuates NMDA receptor-mediated neuronal cell death and prevents the associated reduction in Bcl-2 expression.

PubMed

Schelman, William R; Andres, Robert; Ferguson, Paul; Orr, Brent; Kang, Evan; Weyhenmeyer, James A

2004-09-10

While angiotensin II (Ang II) plays a major role in the regulation of blood pressure, fluid homeostasis and neuroendocrine function, recent studies have also implicated the peptide hormone in cell growth, differentiation and apoptosis. In support of this, we have previously demonstrated that Ang II attenuates N-methyl-D-aspartate (NMDA) receptor signaling [Molec. Brain Res. 48 (1997) 197]. To further examine the modulatory role of Ang II on NMDA receptor function, we investigated the effect of angiotensin receptor (AT) activation on NMDA-mediated cell death and the accompanying decrease in Bcl-2 expression. The viability of differentiated N1E-115 and NG108-15 neuronal cell lines was reduced following exposure to NMDA in a dose-dependent manner. MTT analysis (mitochondrial integrity) revealed a decrease in cell survival of 49.4+/-12.3% in NG108 cells and 79.9+/-6.8% in N1E cells following treatment with 10 mM NMDA for 20 h. Cytotoxicity in N1E cells was inhibited by the noncompetitive NMDA receptor antagonist, MK-801. Further, NMDA receptor-mediated cell death in NG108 cells was attenuated by treatment with Ang II. The Ang II effect was inhibited by both AT1 and AT2 receptor antagonists, losartan and PD123319, respectively, suggesting that both receptor subtypes may play a role in the survival effect of Ang II. Since it has been shown that activation of NMDA receptors alters the expression of Bcl-2 family proteins, Western blot analysis was performed in N1E cells to determine whether Ang II alters the NMDA-induced changes in Bcl-2 expression. A concentration-dependent decrease of intracellular Bcl-2 protein levels was observed following treatment with NMDA, and this reduction was inhibited by MK801. Addition of Ang II suppressed the NMDA receptor-mediated reduction in Bcl-2. The Ang II effect on NMDA-mediated changes in Bcl-2 levels was blocked by PD123319, but was not significantly changed by losartan, suggesting AT2 receptor specificity. Taken together, these

Soluble Tumor Necrosis Factor Alpha Promotes Retinal Ganglion Cell Death in Glaucoma via Calcium-Permeable AMPA Receptor Activation.

PubMed

Cueva Vargas, Jorge L; Osswald, Ingrid K; Unsain, Nicolas; Aurousseau, Mark R; Barker, Philip A; Bowie, Derek; Di Polo, Adriana

2015-09-02

Loss of vision in glaucoma results from the selective death of retinal ganglion cells (RGCs). Tumor necrosis factor α (TNFα) signaling has been linked to RGC damage, however, the mechanism by which TNFα promotes neuronal death remains poorly defined. Using an in vivo rat glaucoma model, we show that TNFα is upregulated by Müller cells and microglia/macrophages soon after induction of ocular hypertension. Administration of XPro1595, a selective inhibitor of soluble TNFα, effectively protects RGC soma and axons. Using cobalt permeability assays, we further demonstrate that endogenous soluble TNFα triggers the upregulation of Ca(2+)-permeable AMPA receptor (CP-AMPAR) expression in RGCs of glaucomatous eyes. CP-AMPAR activation is not caused by defects in GluA2 subunit mRNA editing, but rather reflects selective downregulation of GluA2 in neurons exposed to elevated eye pressure. Intraocular administration of selective CP-AMPAR blockers promotes robust RGC survival supporting a critical role for non-NMDA glutamate receptors in neuronal death. Our study identifies glia-derived soluble TNFα as a major inducer of RGC death through activation of CP-AMPARs, thereby establishing a novel link between neuroinflammation and cell loss in glaucoma. Tumor necrosis factor α (TNFα) has been implicated in retinal ganglion cell (RGC) death, but how TNFα exerts this effect is poorly understood. We report that ocular hypertension, a major risk factor in glaucoma, upregulates TNFα production by Müller cells and microglia. Inhibition of soluble TNFα using a dominant-negative strategy effectively promotes RGC survival. We find that TNFα stimulates the expression of calcium-permeable AMPA receptors (CP-AMPAR) in RGCs, a response that does not depend on abnormal GluA2 mRNA editing but on selective downregulation of the GluA2 subunit by these neurons. Consistent with this, CP-AMPAR blockers promote robust RGC survival supporting a critical role for non-NMDA glutamate receptors

Death receptor 3 signaling enhances proliferation of human regulatory T cells.

PubMed

Bittner, Sebastian; Knoll, Gertrud; Ehrenschwender, Martin

2017-04-01

Exploiting regulatory T cells (Tregs) to control aberrant immune reactions is a promising therapeutic approach, but is hampered by their relative paucity. In mice, activation of death receptor 3 (DR3), a member of the TNF-receptor superfamily (TNFRSF), increases Treg frequency and efficiently controls exuberant immune activation. For human Tregs, neither DR3 expression nor potential functions have been described. Here, we show that human Tregs express DR3 and demonstrate DR3-mediated activation of p38, ERK, and NFκB. DR3 stimulation enhances Treg expansion ex vivo while retaining their suppressive capacity. In summary, our results establish a functional role for DR3 signaling in human Tregs and could potentially help to tailor Treg-based therapies. © 2017 Federation of European Biochemical Societies.

Secreted calmodulin-like skin protein inhibits neuronal death in cell-based Alzheimer's disease models via the heterotrimeric Humanin receptor

PubMed Central

Hashimoto, Y; Nawa, M; Kurita, M; Tokizawa, M; Iwamatsu, A; Matsuoka, M

2013-01-01

Humanin is a secreted bioactive peptide that is protective in a variety of death models, including cell-based neuronal death models related to Alzheimer's disease (AD). To mediate the protective effect in AD-related death models, Humanin signals via a cell-surface receptor that is generally composed of three subunits: ciliary neurotrophic factor receptor α, WSX-1 and gp130 (heterotrimeric Humanin receptor; htHNR). However, the protective effect of Humanin via the htHNR is weak (EC50=1–10 μℳ); therefore, it is possible that another physiological agonist for this receptor exists in vivo. In the current study, calmodulin-like skin protein (CLSP), a calmodulin relative with an undefined function, was shown to be secreted and inhibit neuronal death via the htHNR with an EC50 of 10–100 pℳ. CLSP was highly expressed in the skin, and the concentration in circulating normal human blood was ∼5 nℳ. When administered intraperitoneally in mice, recombinant CLSP was transported across the blood-cerebrospinal fluid (CSF)-barrier and its concentration in the CSF reaches 1/100 of its serum concentration at 1 h after injection. These findings suggest that CLSP is a physiological htHNR agonist. PMID:23519124

Simultaneous induction of apoptotic, autophagic, and necrosis-like cell death by monoclonal antibodies recognizing chicken transferrin receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohno, Yoshiya; Yagi, Hideki; Nakamura, Masanori

Programmed cell death (PCD) is categorized as apoptotic, autophagic, or necrosis-like. Although the possibility that plural (two or three) death signals could be induced by a given stimulus has been reported, the precise mechanisms regulating PCD are not well understood. Recently, we have obtained two anti-chicken transferrin receptor (TfR) monoclonal antibodies (mAbs; D18 and D19) inducing a unique cell death. Although the cell death had several features of apoptosis, autophagic and necrosis-like morphological alterations were simultaneously observed in electron microphotographs. In addition to cells with condensed chromatin and an intact plasma membrane (apoptotic cells), cells having many vacuoles in themore » cytoplasm (autophagic cells), and enlarged cells with ruptured plasma membranes (necrosis-like cells) were observed in DT40 cells treated with the mAbs, however, the latter two types of dead cells were not detected upon treatment with staurosporine, a typical apoptosis inducer. In autophagic cells, numerous membrane-bound vesicles occupying most of the cytoplasmic space, which frequently contained electron-dense materials from cytoplasmic fragments and organelles, were observed. The simultaneous induction of multiple death signals from a stimulus via the TfR is of great interest to those researching cell death. In addition, activation of caspases was observed in DT40 cells treated with D19, however, the cell death was not inhibited with z-VAD-fmk, a pan-caspase inhibitor, suggesting that at least in part, a caspase-independent pathway is involved in the TfR-mediated cell death.« less

Ruthenium complexes with phenylterpyridine derivatives target cell membrane and trigger death receptors-mediated apoptosis in cancer cells.

PubMed

Deng, Zhiqin; Gao, Pan; Yu, Lianling; Ma, Bin; You, Yuanyuan; Chan, Leung; Mei, Chaoming; Chen, Tianfeng

2017-06-01

Elucidation of the communication between metal complexes and cell membrane may provide useful information for rational design of metal-based anticancer drugs. Herein we synthesized a novel class of ruthenium (Ru) complexes containing phtpy derivatives (phtpy = phenylterpyridine), analyzed their structure-activity relationship and revealed their action mechanisms. The result showed that, the increase in the planarity of hydrophobic Ru complexes significantly enhanced their lipophilicity and cellular uptake. Meanwhile, the introduction of nitro group effectively improved their anticancer efficacy. Further mechanism studies revealed that, complex (2c), firstly accumulated on cell membrane and interacted with death receptors to activate extrinsic apoptosis signaling pathway. The complex was then transported into cell cytoplasm through transferrin receptor-mediated endocytosis. Most of the intracellular 2c accumulated in cell plasma, decreasing the level of cellular ROS, inducing the activation of caspase-9 and thus intensifying the apoptosis. At the same time, the residual 2c can translocate into cell nucleus to interact with DNA, induce DNA damage, activate p53 pathway and enhance apoptosis. Comparing with cisplatin, 2c possesses prolonged circulation time in blood, comparable antitumor ability and importantly, much lower toxicity in vivo. Taken together, this study uncovers the role of membrane receptors in the anticancer actions of Ru complexes, and provides fundamental information for rational design of membrane receptor targeting anticancer drugs. Copyright © 2017 Elsevier Ltd. All rights reserved.

FasL-triggered death of Jurkat cells requires caspase 8-induced, ATP-dependent cross-talk between Fas and the purinergic receptor P2X(7).

PubMed

Aguirre, Adam; Shoji, Kenji F; Sáez, Juan C; Henríquez, Mauricio; Quest, Andrew F G

2013-02-01

Fas ligation via the ligand FasL activates the caspase-8/caspase-3-dependent extrinsic death pathway. In so-called type II cells, an additional mechanism involving tBid-mediated caspase-9 activation is required to efficiently trigger cell death. Other pathways linking FasL-Fas interaction to activation of the intrinsic cell death pathway remain unknown. However, ATP release and subsequent activation of purinergic P2X(7) receptors (P2X(7)Rs) favors cell death in some cells. Here, we evaluated the possibility that ATP release downstream of caspase-8 via pannexin1 hemichannels (Panx1 HCs) and subsequent activation of P2X(7)Rs participate in FasL-stimulated cell death. Indeed, upon FasL stimulation, ATP was released from Jurkat cells in a time- and caspase-8-dependent manner. Fas and Panx1 HCs colocalized and inhibition of the latter, but not connexin hemichannels, reduced FasL-induced ATP release. Extracellular apyrase, which hydrolyzes ATP, reduced FasL-induced death. Also, oxidized-ATP or Brilliant Blue G, two P2X(7)R blockers, reduced FasL-induced caspase-9 activation and cell death. These results represent the first evidence indicating that the two death receptors, Fas and P2X(7)R connect functionally via caspase-8 and Panx1 HC-mediated ATP release to promote caspase-9/caspase-3-dependent cell death in lymphoid cells. Thus, a hitherto unsuspected route was uncovered connecting the extrinsic to the intrinsic pathway to amplify death signals emanating from the Fas receptor in type II cells. Copyright © 2012 Wiley Periodicals, Inc.

The intracellular carboxyl tail of the PAR-2 receptor controls intracellular signaling and cell death.

PubMed

Zhu, Zhihui; Stricker, Rolf; Li, Rong yu; Zündorf, Gregor; Reiser, Georg

2015-03-01

The protease-activated receptors are a group of unique G protein-coupled receptors, including PAR-1, PAR-2, PAR-3 and PAR-4. PAR-2 is activated by multiple trypsin-like serine proteases, including trypsin, tryptase and coagulation proteases. The clusters of phosphorylation sites in the PAR-2 carboxyl tail are suggested to be important for the binding of adaptor proteins to initiate intracellular signaling to Ca(2+) and mitogen-activated protein kinases. To explore the functional role of PAR-2 carboxyl tail in controlling intracellular Ca(2+), ERK and AKT signaling, a series of truncated mutants containing different clusters of serines/threonines were generated and expressed in HEK293 cells. Firstly, we observed that lack of the complete C-terminus of PAR-2 in a mutated receptor gave a relatively low level of localization on the cell plasma membrane. Secondly, the shortened carboxyl tail containing 13 amino acids was sufficient for receptor internalization. Thirdly, the cells expressing truncation mutants showed deficits in their capacity to couple to intracellular Ca(2+) and ERK and AKT signaling upon trypsin challenge. In addition, HEK293 cells carrying different PAR-2 truncation mutants displayed decreased levels of cell survival after long-lasting trypsin stimulation. In summary, the PAR-2 carboxyl tail was found to control the receptor localization, internalization, intracellular Ca(2+) responses and signaling to ERK and AKT. The latter can be considered to be important for cell death control.

Synergistic interaction of the cannabinoid and death receptor systems - a potential target for future cancer therapies?

PubMed

Keresztes, Attila; Streicher, John M

2017-10-01

Cannabinoid receptors have been shown to interact with other receptors, including tumor necrosis factor receptor superfamily (TNFRS) members, to induce cancer cell death. When cannabinoids and death-inducing ligands (including TNF-related apoptosis-inducing ligand) are administered together, they have been shown to synergize and demonstrate enhanced antitumor activity in vitro. Certain cannabinoid ligands have been shown to sensitize cancer cells and synergistically interact with members of the TNFRS, thus suggesting that the combination of cannabinoids with death receptor (DR) ligands induces additive or synergistic tumor cell death. This review summarizes recent findings on the interaction of the cannabinoid and DR systems and suggests possible clinical co-application of cannabinoids and DR ligands in the treatment of various malignancies. © 2017 Federation of European Biochemical Societies.

Accelerated retinal ganglion cell death in mice deficient in the Sigma-1 receptor.

PubMed

Mavlyutov, Timur A; Nickells, Robert W; Guo, Lian-Wang

2011-04-26

The sigma-1 receptor (σR1), a ligand-operated chaperone, has been inferred to be neuroprotective in previous studies using σR1 ligands. The σR1 specificity of the protective function, however, has yet to be firmly established, due to the existence of non-σR1 targets of the ligands. Here, we used the σR1-knockout mouse (Sigmar1(-/-)) to demonstrate unambiguously the role of the σR1 in protecting the retinal ganglion cells against degeneration after acute damage to the optic nerve. Retinal σR binding sites were labeled with radioiodinated σR ligands and analyzed by autoradiography. Localization of the σR1 was performed by indirect immunofluorescence on frozen retinal sections. Retinal ganglion cell death was induced by acute optic nerve crush in wild-type and Sigmar1(-/-) mice. Surviving cells in the ganglion cell layer were counted on Nissl-stained retinal whole mounts 7 days after the crush surgery. Photoaffinity labeling indicated the presence of the σR1 in the retina, in concentrations equivalent to those in liver tissue. Immunolabeling detected this receptor in cells of both the ganglion cell layer and the photoreceptor cell layer in wild-type retinas. Quantification of cells remaining after optic nerve crush showed that 86.8±7.9% cells remained in the wild-type ganglion cell layer, but only 68.3±3.4% survived in the Sigmar1(-/-), demonstrating a significant difference between the wild-type and the Sigmar1(-/-) in crush-induced ganglion cell loss. Our data indicated faster retinal ganglion cell death in Sigmar1(-/-) than in wild-type mice under the stresses caused by optic nerve crush, providing direct evidence for a role of the σR1 in alleviating retinal degeneration. This conclusion is consistent with the previous pharmacological studies using σR1 agonists. Thus, our study supports the idea that the σR1 is a promising therapeutic target for neurodegenerative retinal diseases, such as glaucoma.

Natriuretic peptide receptor A inhibition suppresses gastric cancer development through reactive oxygen species-mediated G2/M cell cycle arrest and cell death.

PubMed

Li, Zheng; Wang, Ji-Wei; Wang, Wei-Zhi; Zhi, Xiao-Fei; Zhang, Qun; Li, Bo-Wen; Wang, Lin-Jun; Xie, Kun-Ling; Tao, Jin-Qiu; Tang, Jie; Wei, Song; Zhu, Yi; Xu, Hao; Zhang, Dian-Cai; Yang, Li; Xu, Ze-Kuan

2016-10-01

Natriuretic peptide receptor A (NPRA), the major receptor for atrial natriuretic peptide (ANP), has been implicated in tumorigenesis; however, the role of ANP-NPRA signaling in the development of gastric cancer remains unclear. Immunohistochemical analyses indicated that NPRA expression was positively associated with gastric tumor size and cancer stage. NPRA inhibition by shRNA induced G2/M cell cycle arrest, cell death, and autophagy in gastric cancer cells, due to accumulation of reactive oxygen species (ROS). Either genetic or pharmacologic inhibition of autophagy led to caspase-dependent cell death. Therefore, autophagy induced by NPRA silencing may represent a cytoprotective mechanism. ROS accumulation activated c-Jun N-terminal kinase (JNK) and AMP-activated protein kinase (AMPK). ROS-mediated activation of JNK inhibited cell proliferation by disturbing cell cycle and decreased cell viability. In addition, AMPK activation promoted autophagy in NPRA-downregulated cancer cells. Overall, our results indicate that the inhibition of NPRA suppresses gastric cancer development and targeting NPRA may represent a promising strategy for the treatment of gastric cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Nanoarchitectured electrochemical cytosensors for selective detection of leukemia cells and quantitative evaluation of death receptor expression on cell surfaces.

PubMed

Zheng, Tingting; Fu, Jia-Ju; Hu, Lihui; Qiu, Fan; Hu, Minjin; Zhu, Jun-Jie; Hua, Zi-Chun; Wang, Hui

2013-06-04

The variable susceptibility to the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment observed in various types of leukemia cells is related to the difference in the expression levels of death receptors, DR4 and DR5, on the cell surfaces. Quantifying the DR4/DR5 expression status on leukemia cell surfaces is of vital importance to the development of diagnostic tools to guide death receptor-based leukemia treatment. Taking the full advantages of novel nanobiotechnology, we have developed a robust electrochemical cytosensing approach toward ultrasensitive detection of leukemia cells with detection limit as low as ~40 cells and quantitative evaluation of DR4/DR5 expression on leukemia cell surfaces. The optimization of electron transfer and cell capture processes at specifically tailored nanobiointerfaces and the incorporation of multiple functions into rationally designed nanoprobes provide unique opportunities of integrating high specificity and signal amplification on one electrochemical cytosensor. The high sensitivity and selectivity of this electrochemical cytosensing approach also allows us to evaluate the dynamic alteration of DR4/DR5 expression on the surfaces of living cells in response to drug treatments. Using the TRAIL-resistant HL-60 cells and TRAIL-sensitive Jurkat cells as model cells, we have further verified that the TRAIL susceptibility of various types of leukemia cells is directly correlated to the surface expression levels of DR4/DR5. This versatile electrochemical cytosensing platform is believed to be of great clinical value for the early diagnosis of human leukemia and the evaluation of therapeutic effects on leukemia patients after radiation therapy or drug treatment.

A type III effector antagonizes death receptor signalling during bacterial gut infection.

PubMed

Pearson, Jaclyn S; Giogha, Cristina; Ong, Sze Ying; Kennedy, Catherine L; Kelly, Michelle; Robinson, Keith S; Lung, Tania Wong Fok; Mansell, Ashley; Riedmaier, Patrice; Oates, Clare V L; Zaid, Ali; Mühlen, Sabrina; Crepin, Valerie F; Marches, Olivier; Ang, Ching-Seng; Williamson, Nicholas A; O'Reilly, Lorraine A; Bankovacki, Aleksandra; Nachbur, Ueli; Infusini, Giuseppe; Webb, Andrew I; Silke, John; Strasser, Andreas; Frankel, Gad; Hartland, Elizabeth L

2013-09-12

Successful infection by enteric bacterial pathogens depends on the ability of the bacteria to colonize the gut, replicate in host tissues and disseminate to other hosts. Pathogens such as Salmonella, Shigella and enteropathogenic and enterohaemorrhagic (EPEC and EHEC, respectively) Escherichia coli use a type III secretion system (T3SS) to deliver virulence effector proteins into host cells during infection that promote colonization and interfere with antimicrobial host responses. Here we report that the T3SS effector NleB1 from EPEC binds to host cell death-domain-containing proteins and thereby inhibits death receptor signalling. Protein interaction studies identified FADD, TRADD and RIPK1 as binding partners of NleB1. NleB1 expressed ectopically or injected by the bacterial T3SS prevented Fas ligand or TNF-induced formation of the canonical death-inducing signalling complex (DISC) and proteolytic activation of caspase-8, an essential step in death-receptor-induced apoptosis. This inhibition depended on the N-acetylglucosamine transferase activity of NleB1, which specifically modified Arg 117 in the death domain of FADD. The importance of the death receptor apoptotic pathway to host defence was demonstrated using mice deficient in the FAS signalling pathway, which showed delayed clearance of the EPEC-like mouse pathogen Citrobacter rodentium and reversion to virulence of an nleB mutant. The activity of NleB suggests that EPEC and other attaching and effacing pathogens antagonize death-receptor-induced apoptosis of infected cells, thereby blocking a major antimicrobial host response.

A type III effector antagonises death receptor signalling during bacterial gut infection

PubMed Central

Pearson, Jaclyn S; Giogha, Cristina; Ong, Sze Ying; Kennedy, Catherine L; Kelly, Michelle; Robinson, Keith S; Wong, Tania; Mansell, Ashley; Riedmaier, Patrice; Oates, Clare VL; Zaid, Ali; Mühlen, Sabrina; Crepin, Valerie F; Marches, Olivier; Ang, Ching-Seng; Williamson, Nicholas A; O’Reilly, Lorraine A; Bankovacki, Aleksandra; Nachbur, Ueli; Infusini, Giuseppe; Webb, Andrew I; Silke, John; Strasser, Andreas; Frankel, Gad; Hartland, Elizabeth L

2013-01-01

Successful infection by enteric bacterial pathogens depends on the ability of the bacteria to colonise the gut, replicate in host tissues and disseminate to other hosts. Pathogens such as Salmonella, Shigella and enteropathogenic and enterohaemorrhagic E. coli (EPEC and EHEC), utilise a type III secretion system (T3SS) to deliver virulence effector proteins into host cells during infection that promote colonisation and interfere with antimicrobial host responses 1-3. Here we report that the T3SS effector NleB1 from EPEC binds to host cell death domain containing proteins and thereby inhibits death receptor signalling. Protein interaction studies identified FADD, TRADD and RIPK1 as binding partners of NleB1. NleB1 expressed ectopically or injected by the bacterial T3SS prevented Fas ligand or TNF-induced formation of the canonical death inducing signalling complex (DISC) and proteolytic activation of caspase-8, an essential step in death receptor induced apoptosis. This inhibition depended on the N-GlcNAc transferase activity of NleB1, which specifically modified Arg117 in the death domain of FADD. The importance of the death receptor apoptotic pathway to host defence was demonstrated using mice deficient in the FAS signalling pathway, which showed delayed clearance of the EPEC-like mouse pathogen Citrobacter rodentium and reversion to virulence of an nleB mutant. The activity of NleB suggests that EPEC and other attaching and effacing (A/E) pathogens antagonise death receptor induced apoptosis of infected cells, thereby blocking a major antimicrobial host response. PMID:24025841

Cell death is induced by ciglitazone, a peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) agonist, independently of PPAR{gamma} in human glioma cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Myoung Woo; Kim, Dae Seong; Kim, Hye Ryung

Highlights: Black-Right-Pointing-Pointer Greater than 30 {mu}M ciglitazone induces cell death in glioma cells. Black-Right-Pointing-Pointer Cell death by ciglitazone is independent of PPAR{gamma} in glioma cells. Black-Right-Pointing-Pointer CGZ induces cell death by the loss of MMP via decreased Akt. -- Abstract: Peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) regulates multiple signaling pathways, and its agonists induce apoptosis in various cancer cells. However, their role in cell death is unclear. In this study, the relationship between ciglitazone (CGZ) and PPAR{gamma} in CGZ-induced cell death was examined. At concentrations of greater than 30 {mu}M, CGZ, a synthetic PPAR{gamma} agonist, activated caspase-3 and induced apoptosis inmore » T98G cells. Treatment of T98G cells with less than 30 {mu}M CGZ effectively induced cell death after pretreatment with 30 {mu}M of the PPAR{gamma} antagonist GW9662, although GW9662 alone did not induce cell death. This cell death was also observed when cells were co-treated with CGZ and GW9662, but was not observed when cells were treated with CGZ prior to GW9662. In cells in which PPAR{gamma} was down-regulated cells by siRNA, lower concentrations of CGZ (<30 {mu}M) were sufficient to induce cell death, although higher concentrations of CGZ ( Greater-Than-Or-Slanted-Equal-To 30 {mu}M) were required to induce cell death in control T98G cells, indicating that CGZ effectively induces cell death in T98G cells independently of PPAR{gamma}. Treatment with GW9662 followed by CGZ resulted in a down-regulation of Akt activity and the loss of mitochondrial membrane potential (MMP), which was accompanied by a decrease in Bcl-2 expression and an increase in Bid cleavage. These data suggest that CGZ is capable of inducing apoptotic cell death independently of PPAR{gamma} in glioma cells, by down-regulating Akt activity and inducing MMP collapse.« less

Pore-forming toxin-mediated ion dysregulation leads to death receptor-independent necroptosis of lung epithelial cells during bacterial pneumonia

PubMed Central

González-Juarbe, Norberto; Bradley, Kelley Margaret; Shenoy, Anukul Taranath; Gilley, Ryan Paul; Reyes, Luis Felipe; Hinojosa, Cecilia Anahí; Restrepo, Marcos Ignacio; Dube, Peter Herman; Bergman, Molly Ann; Orihuela, Carlos Javier

2017-01-01

We report that pore-forming toxins (PFTs) induce respiratory epithelial cell necroptosis independently of death receptor signaling during bacterial pneumonia. Instead, necroptosis was activated as a result of ion dysregulation arising from membrane permeabilization. PFT-induced necroptosis required RIP1, RIP3 and MLKL, and could be induced in the absence or inhibition of TNFR1, TNFR2 and TLR4 signaling. We detected activated MLKL in the lungs from mice and nonhuman primates experiencing Serratia marcescens and Streptococcus pneumoniae pneumonia, respectively. We subsequently identified calcium influx and potassium efflux as the key initiating signals responsible for necroptosis; also that mitochondrial damage was not required for necroptosis activation but was exacerbated by MLKL activation. PFT-induced necroptosis in respiratory epithelial cells did not involve CamKII or reactive oxygen species. KO mice deficient in MLKL or RIP3 had increased survival and reduced pulmonary injury during S. marcescens pneumonia. Our results establish necroptosis as a major cell death pathway active during bacterial pneumonia and that necroptosis can occur without death receptor signaling. PMID:28387756

Pore-forming toxin-mediated ion dysregulation leads to death receptor-independent necroptosis of lung epithelial cells during bacterial pneumonia.

PubMed

González-Juarbe, Norberto; Bradley, Kelley Margaret; Shenoy, Anukul Taranath; Gilley, Ryan Paul; Reyes, Luis Felipe; Hinojosa, Cecilia Anahí; Restrepo, Marcos Ignacio; Dube, Peter Herman; Bergman, Molly Ann; Orihuela, Carlos Javier

2017-05-01

We report that pore-forming toxins (PFTs) induce respiratory epithelial cell necroptosis independently of death receptor signaling during bacterial pneumonia. Instead, necroptosis was activated as a result of ion dysregulation arising from membrane permeabilization. PFT-induced necroptosis required RIP1, RIP3 and MLKL, and could be induced in the absence or inhibition of TNFR1, TNFR2 and TLR4 signaling. We detected activated MLKL in the lungs from mice and nonhuman primates experiencing Serratia marcescens and Streptococcus pneumoniae pneumonia, respectively. We subsequently identified calcium influx and potassium efflux as the key initiating signals responsible for necroptosis; also that mitochondrial damage was not required for necroptosis activation but was exacerbated by MLKL activation. PFT-induced necroptosis in respiratory epithelial cells did not involve CamKII or reactive oxygen species. KO mice deficient in MLKL or RIP3 had increased survival and reduced pulmonary injury during S. marcescens pneumonia. Our results establish necroptosis as a major cell death pathway active during bacterial pneumonia and that necroptosis can occur without death receptor signaling.

Enhancement of death-receptor induced caspase-8-activation in the death-inducing signalling complex by uncoupling of oxidative phosphorylation.

PubMed

Vier, Juliane; Gerhard, Monika; Wagner, Hermann; Häcker, Georg

2004-01-01

Signalling through the death receptor CD95 induces apoptosis by formation of a signalling complex at the cell membrane and subsequent caspase-8 and caspase-3-activation. Treatment of Jurkat T cells with protonophores across the mitochondrial membrane such as 2,4-dinitrophenol (DNP) enhances the death-inducing capacity of CD95. In this study, we show that this enhancement is due to the specific acceleration of caspase-8-processing and activation at the CD95-receptor. DNP-treatment did not affect NF-kappaB-induction by CD95. Immunoprecipitation experiments showed that the amounts of the adapter FADD/MORT1 and pro-caspase-8 at the CD95-receptor were not altered by DNP. Subcellular fractionation studies revealed that the amount of mature caspase-8 but not pro-caspase at the membrane was increased following CD95-stimulation in the presence of DNP. As a consequence of caspase-activation, c-FLIP-levels in the cytosol decreased. In Jurkat cells overexpressing c-FLIPS, DNP was still able to enhance caspase-activation. The enhancing capacity of DNP was seen in some cell lines (Jurkat, CEM and HeLa) but not in SKW6 cells and was also found in mitogen-stimulated human T cells. Furthermore, the enhancement extended to TRAIL-induced caspase-activation. Thus, a mechanism exists by which caspase-8-activation can be accelerated at death receptors and this mechanism can be triggered by targeting mitochondrial oxidative phosphorylation.

Lack of T-cell receptor-induced signaling is crucial for CD95 ligand up-regulation and protects cutaneous T-cell lymphoma cells from activation-induced cell death.

PubMed

Klemke, Claus-Detlev; Brenner, Dirk; Weiss, Eva-Maria; Schmidt, Marc; Leverkus, Martin; Gülow, Karsten; Krammer, Peter H

2009-05-15

Restimulation of previously activated T cells via the T-cell receptor (TCR) leads to activation-induced cell death (AICD), which is, at least in part, dependent on the death receptor CD95 (APO-1, FAS) and its natural ligand (CD95L). Here, we characterize cutaneous T-cell lymphoma (CTCL) cells (CTCL tumor cell lines and primary CTCL tumor cells from CTCL patients) as AICD resistant. We show that CTCL cells have elevated levels of the CD95-inhibitory protein cFLIP. However, cFLIP is not responsible for CTCL AICD resistance. Instead, our data suggest that reduced TCR-proximal signaling in CTCL cells is responsible for the observed AICD resistance. CTCL cells exhibit no PLC-gamma1 activity, resulting in an impaired Ca(2+)release and reduced generation of reactive oxygen species upon TCR stimulation. Ca(2+) and ROS production are crucial for up-regulation of CD95L and reconstitution of both signals resulted in AICD sensitivity of CTCL cells. In accordance with these data, CTCL tumor cells from patients with Sézary syndrome do not up-regulate CD95L upon TCR-stimulation and are therefore resistant to AICD. These results show a novel mechanism of AICD resistance in CTCL that could have future therapeutic implications to overcome apoptosis resistance in CTCL patients.

Coengagement of CD16 and CD94 receptors mediates secretion of chemokines and induces apoptotic death of naive natural killer cells.

PubMed

Jewett, Anahid; Cacalano, Nicholas A; Head, Christian; Teruel, Antonia

2006-04-01

Down-modulation of CD16 (FcgammaRIII) receptors and loss of natural killer (NK) cell function have been observed in oral cancer patients. However, neither the mechanisms nor the significance of the decrease in CD16 receptors have been fully understood. The cytotoxic activity and survival of NK cells are negatively regulated by antibodies directed against CD16 surface receptor. The addition of anti-CD94 antibody in combination with either F(ab')(2) fragment or intact anti-CD16 antibody to NK cells resulted in significant inhibition of NK cell cytotoxic function and induction of apoptosis in resting human peripheral blood NK cells. Addition of interleukin-2 to anti-CD16 and/or anti-CD94 antibody-treated NK cells significantly inhibited apoptosis and increased the function of NK cells. There was a significant increase in tumor necrosis factor-alpha (TNF-alpha) but not IFN-gamma secretion in NK cells treated either with anti-CD16 antibody alone or in combination with anti-CD94 antibodies. Consequently, the addition of anti-TNF-alpha antibody partially inhibited apoptosis of NK cells mediated by the combination of anti-CD94 and anti-CD16 antibodies. Increase in apoptotic death of NK cells also correlated with an increase in type 2 inflammatory cytokines and in the induction of chemokines. Thus, we conclude that binding of antibodies to CD16 and CD94 NK cell receptors induces death of the NK cells and signals for the release of chemokines.

Accelerated retinal ganglion cell death in mice deficient in the Sigma-1 receptor

PubMed Central

Mavlyutov, Timur A.; Nickells, Robert W.

2011-01-01

Purpose The sigma-1 receptor (σR1), a ligand-operated chaperone, has been inferred to be neuroprotective in previous studies using σR1 ligands. The σR1 specificity of the protective function, however, has yet to be firmly established, due to the existence of non-σR1 targets of the ligands. Here, we used the σR1-knockout mouse (Sigmar1−/−) to demonstrate unambiguously the role of the σR1 in protecting the retinal ganglion cells against degeneration after acute damage to the optic nerve. Methods Retinal σR binding sites were labeled with radioiodinated σR ligands and analyzed by autoradiography. Localization of the σR1 was performed by indirect immunofluorescence on frozen retinal sections. Retinal ganglion cell death was induced by acute optic nerve crush in wild-type and Sigmar1−/− mice. Surviving cells in the ganglion cell layer were counted on Nissl-stained retinal whole mounts 7 days after the crush surgery. Results Photoaffinity labeling indicated the presence of the σR1 in the retina, in concentrations equivalent to those in liver tissue. Immunolabeling detected this receptor in cells of both the ganglion cell layer and the photoreceptor cell layer in wild-type retinas. Quantification of cells remaining after optic nerve crush showed that 86.8±7.9% cells remained in the wild-type ganglion cell layer, but only 68.3±3.4% survived in the Sigmar1−/−, demonstrating a significant difference between the wild-type and the Sigmar1−/− in crush-induced ganglion cell loss. Conclusions Our data indicated faster retinal ganglion cell death in Sigmar1−/− than in wild-type mice under the stresses caused by optic nerve crush, providing direct evidence for a role of the σR1 in alleviating retinal degeneration. This conclusion is consistent with the previous pharmacological studies using σR1 agonists. Thus, our study supports the idea that the σR1 is a promising therapeutic target for neurodegenerative retinal diseases, such as glaucoma. PMID

Fas cell surface death receptor controls hepatic lipid metabolism by regulating mitochondrial function.

PubMed

Item, Flurin; Wueest, Stephan; Lemos, Vera; Stein, Sokrates; Lucchini, Fabrizio C; Denzler, Rémy; Fisser, Muriel C; Challa, Tenagne D; Pirinen, Eija; Kim, Youngsoo; Hemmi, Silvio; Gulbins, Erich; Gross, Atan; O'Reilly, Lorraine A; Stoffel, Markus; Auwerx, Johan; Konrad, Daniel

2017-09-07

Nonalcoholic fatty liver disease is one of the most prevalent metabolic disorders and it tightly associates with obesity, type 2 diabetes, and cardiovascular disease. Reduced mitochondrial lipid oxidation contributes to hepatic fatty acid accumulation. Here, we show that the Fas cell surface death receptor (Fas/CD95/Apo-1) regulates hepatic mitochondrial metabolism. Hepatic Fas overexpression in chow-fed mice compromises fatty acid oxidation, mitochondrial respiration, and the abundance of mitochondrial respiratory complexes promoting hepatic lipid accumulation and insulin resistance. In line, hepatocyte-specific ablation of Fas improves mitochondrial function and ameliorates high-fat-diet-induced hepatic steatosis, glucose tolerance, and insulin resistance. Mechanistically, Fas impairs fatty acid oxidation via the BH3 interacting-domain death agonist (BID). Mice with genetic or pharmacological inhibition of BID are protected from Fas-mediated impairment of mitochondrial oxidation and hepatic steatosis. We suggest Fas as a potential novel therapeutic target to treat obesity-associated fatty liver and insulin resistance.Hepatic steatosis is a common disease closely associated with metabolic syndrome and insulin resistance. Here Item et al. show that Fas, a member of the TNF receptor superfamily, contributes to mitochondrial dysfunction, steatosis development, and insulin resistance under high fat diet.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marrero, Maria Teresa; Estevez, Sara; Negrin, Gledy

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 inhibitormore » 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.« less

Catalytically active Yersinia outer protein P induces cleavage of RIP and caspase-8 at the level of the DISC independently of death receptors in dendritic cells.

PubMed

Gröbner, Sabine; Adkins, Irena; Schulz, Sebastian; Richter, Kathleen; Borgmann, Stefan; Wesselborg, Sebastian; Ruckdeschel, Klaus; Micheau, Olivier; Autenrieth, Ingo B

2007-10-01

Yersinia outer protein P (YopP) is injected by Y. enterocolitica into host cells thereby inducing apoptotic and necrosis-like cell death in dendritic cells (DC). Here we show the pathways involved in DC death caused by the catalytic activity of YopP. Infection with Yersinia enterocolitica, translocating catalytically active YopP into DC, triggered procaspase-8 cleavage and c-FLIPL degradation. YopP-dependent caspase-8 activation was, however, not mediated by tumor necrosis factor (TNF) receptor family members since the expression of both CD95/Fas/APO-1 and TRAIL-R2 on DC was low, and DC were resistant to apoptosis induced by agonistic anti-CD95 antibodies or TNF-related apoptosis-inducing ligand (TRAIL). Moreover, DC from TNF-Rp55-/- mice were not protected against YopP-induced cell death demonstrating that TNF-R1 is also not involved in this process. Activation of caspase-8 was further investigated by coimmunoprecitation of FADD from Yersinia-infected DC. We found that both cleaved caspase-8 and receptor interacting protein 1 (RIP1) were associated with the Fas-associated death domain (FADD) indicating the formation of an atypical death-inducing signaling complex (DISC). Furthermore, degradation of RIP mediated by the Hsp90 inhibitor geldanamycin significantly impaired YopP-induced cell death. Altogether our findings indicate that Yersinia-induced DC death is independent of death domain containing receptors, but mediated by RIP and caspase-8 at the level of DISC.

A receptor tyrosine kinase inhibitor, Tyrphostin A9 induces cancer cell death through Drp1 dependent mitochondria fragmentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, So Jung; Park, Young Jun; Shin, Ji Hyun

2011-05-13

Highlights: {yields} We screened and identified Tyrphostin A9, a receptor tyrosine kinase inhibitor as a strong mitochondria fission inducer. {yields} Tyrphostin A9 treatment promotes mitochondria dysfunction and contributes to cytotoxicity in cancer cells. {yields} Tyrphostin A9 induces apoptotic cell death through a Drp1-mediated pathway. {yields} Our studies suggest that Tyrphostin A9 induces mitochondria fragmentation and apoptotic cell death via Drp1 dependently. -- Abstract: Mitochondria dynamics controls not only their morphology but also functions of mitochondria. Therefore, an imbalance of the dynamics eventually leads to mitochondria disruption and cell death. To identify specific regulators of mitochondria dynamics, we screened a bioactivemore » chemical compound library and selected Tyrphostin A9, a tyrosine kinase inhibitor, as a potent inducer of mitochondrial fission. Tyrphostin A9 treatment resulted in the formation of fragmented mitochondria filament. In addition, cellular ATP level was decreased and the mitochondrial membrane potential was collapsed in Tyr A9-treated cells. Suppression of Drp1 activity by siRNA or over-expression of a dominant negative mutant of Drp1 inhibited both mitochondrial fragmentation and cell death induced by Tyrpohotin A9. Moreover, treatment of Tyrphostin A9 also evoked mitochondrial fragmentation in other cells including the neuroblastomas. Taken together, these results suggest that Tyrphostin A9 induces Drp1-mediated mitochondrial fission and apoptotic cell death.« less

Lysosomal membrane permeabilization is an early event in Sigma-2 receptor ligand mediated cell death in pancreatic cancer.

PubMed

Hornick, John R; Vangveravong, Suwanna; Spitzer, Dirk; Abate, Carmen; Berardi, Francesco; Goedegebuure, Peter; Mach, Robert H; Hawkins, William G

2012-05-02

Sigma-2 receptor ligands have been studied for treatment of pancreatic cancer because they are preferentially internalized by proliferating cells and induce apoptosis. This mechanism of apoptosis is poorly understood, with varying reports of caspase-3 dependence. We evaluated multiple sigma-2 receptor ligands in this study, each shown to decrease tumor burden in preclinical models of human pancreatic cancer. Fluorescently labeled sigma-2 receptor ligands of two classes (derivatives of SW43 and PB282) localize to cell membrane components in Bxpc3 and Aspc1 pancreatic cancer cells and accumulate in lysosomes. We found that interactions in the lysosome are critical for cell death following sigma-2 ligand treatment because selective inhibition of a protective lysosomal membrane glycoprotein, LAMP1, with shRNA greatly reduced the viability of cells following treatment. Sigma-2 ligands induced lysosomal membrane permeabilization (LMP) and protease translocation triggering downstream effectors of apoptosis. Subsequently, cellular oxidative stress was greatly increased following treatment with SW43, and the hydrophilic antioxidant N-acetylcysteine (NAC) gave greater protection against this than a lipophilic antioxidant, α-tocopherol (α-toco). Conversely, PB282-mediated cytotoxicity relied less on cellular oxidation, even though α-toco did provide protection from this ligand. In addition, we found that caspase-3 induction was not as significantly inhibited by cathepsin inhibitors as by antioxidants. Both NAC and α-toco protected against caspase-3 induction following PB282 treatment, while only NAC offered protection following SW43 treatment. The caspase-3 inhibitor DEVD-FMK offered significant protection from PB282, but not SW43. Sigma-2 ligand SW43 commits pancreatic cancer cells to death by a caspase-independent process involving LMP and oxidative stress which is protected from by NAC. PB282 however undergoes a caspase-dependent death following LMP protected by DEVD

The metabotropic P2Y4 receptor participates in the commitment to differentiation and cell death of human neuroblastoma SH-SY5Y cells.

PubMed

Cavaliere, Fabio; Nestola, Valeria; Amadio, Susanna; D'Ambrosi, Nadia; Angelini, Daniela F; Sancesario, Giuseppe; Bernardi, Giorgio; Volonté, Cinzia

2005-02-01

Extracellular nucleotides exert a variety of biological actions through different subtypes of P2 receptors. Here we characterized in the human neuroblastoma SH-SY5Y cells the simultaneous presence of various P2 receptors, belonging to the P2X ionotropic and P2Y metabotropic families. Western blot analysis detected the P2X1,2,4,5,6,7 and P2Y1,2,4,6, but not the P2X3 and P2Y12 receptors. We then investigated which biological effects were mediated by the P2Y4 subtype and its physiological pyrimidine agonist UTP. We found that neuronal differentiation of the SH-SY5Y cells with dibutiryl-cAMP increased the expression of the P2Y4 protein and that UTP itself was able to positively interfere with neuritogenesis. Moreover, transient transfection and activation of P2Y4 also facilitated neuritogenesis in SH-SY5Y cells, as detected by morphological phase contrast analysis and confocal examination of neurofilament proteins NFL. This was concurrent with increased transcription of immediate-early genes linked to differentiation such as cdk-5 and NeuroD6, and activity of AP-1 transcription family members such as c-fos, fos-B, and jun-D. Nevertheless, a prolonged activation of the P2Y4 receptor by UTP also induced cell death, both in naive, differentiated, and P2Y4-transfected SH-SY5Y cells, as measured by direct count of intact nuclei and cytofluorimetric analysis of damaged DNA. Taken together, our data indicate that the high expression and activation of the P2Y4 receptor participates in the neuronal differentiation and commitment to death of SH-SY5Y cells.

P2X7 receptor promotes intestinal inflammation in chemically induced colitis and triggers death of mucosal regulatory T cells.

PubMed

Figliuolo, Vanessa R; Savio, Luiz Eduardo Baggio; Safya, Hanaa; Nanini, Hayandra; Bernardazzi, Cláudio; Abalo, Alessandra; de Souza, Heitor S P; Kanellopoulos, Jean; Bobé, Pierre; Coutinho, Cláudia M L M; Coutinho-Silva, Robson

2017-06-01

P2X7 receptor activation contributes to inflammation development in different pathologies. We previously reported that the P2X7 receptor is over-expressed in the gut mucosa of patients with inflammatory bowel disease, and that P2X7 inhibition protects against chemically induced colitis. Here, we investigated in detail the role of the P2X7 receptor in inflammatory bowel disease development, by treating P2X7 knockout (KO) and WT mice with two different (and established) colitis inductors. P2X7 KO mice were protected against gut inflammation induced by 2,4,6-trinitrobenzenesulfonic acid or oxazolone, with no weight loss or gut histological alterations after treatment. P2X7 receptor knockout induced regulatory T cell accumulation in the colon, as evaluated by qRT-PCR for FoxP3 expression and immunostaining for CD90/CD45RB low . Flow cytometry analysis of mesenteric lymph node cells showed that P2X7 activation (by ATP) triggered regulatory T cell death. In addition, such cells from P2X7 KO mice expressed more CD103, suggesting increased migration of regulatory T cells to the colon (relative to the WT). Our results show that the P2X7 has a key role during inflammation development in inflammatory bowel disease, by triggering the death and retention in the mesenteric lymph nodes of regulatory T cells that would otherwise promote immune system tolerance in the gut. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of transglutaminase 2 in PAC1 receptor mediated protection against hypoxia-induced cell death and neurite outgrowth in differentiating N2a neuroblastoma cells.

PubMed

Algarni, Alanood S; Hargreaves, Alan J; Dickenson, John M

2017-03-15

The PAC 1 receptor and tissue transglutaminase (TG2) play important roles in neurite outgrowth and modulation of neuronal cell survival. In this study, we investigated the regulation of TG2 activity by the PAC 1 receptor in retinoic acid-induced differentiating N2a neuroblastoma cells. TG2 transamidase activity was determined using an amine incorporation and a peptide cross linking assay. In situ TG2 activity was assessed by visualising the incorporation of biotin-X-cadaverine using confocal microscopy. TG2 phosphorylation was monitored via immunoprecipitation and Western blotting. The role of TG2 in PAC 1 receptor-induced cytoprotection and neurite outgrowth was investigated by monitoring hypoxia-induced cell death and appearance of axonal-like processes, respectively. The amine incorporation and protein crosslinking activity of TG2 increased in a time and concentration-dependent manner following stimulation with pituitary adenylate cyclase-activating polypeptide-27 (PACAP-27). PACAP-27 mediated increases in TG2 activity were abolished by the TG2 inhibitors Z-DON and R283 and by pharmacological inhibition of protein kinase A (KT 5720 and Rp-cAMPs), protein kinase C (Ro 31-8220), MEK1/2 (PD 98059), and removal of extracellular Ca 2+ . Fluorescence microscopy demonstrated PACAP-27 induced in situ TG2 activity. TG2 inhibition blocked PACAP-27 induced attenuation of hypoxia-induced cell death and outgrowth of axon-like processes. TG2 activation and cytoprotection were also observed in human SH-SY5Y cells. Together, these results demonstrate that TG2 activity was stimulated downstream of the PAC 1 receptor via a multi protein kinase dependent pathway. Furthermore, PAC 1 receptor-induced cytoprotection and neurite outgrowth are dependent upon TG2. These results highlight the importance of TG2 in the cellular functions of the PAC 1 receptor. Copyright © 2017 Elsevier Inc. All rights reserved.

Soluble TL1A is sufficient for activation of death receptor 3.

PubMed

Bittner, Sebastian; Knoll, Gertrud; Füllsack, Simone; Kurz, Maria; Wajant, Harald; Ehrenschwender, Martin

2016-01-01

Death receptor 3 (DR3) is a typical member of the tumor necrosis factor receptor family, and was initially identified as a T-cell co-stimulatory molecule. However, further studies revealed a more complex and partly dichotomous role for DR3 and its ligand TL1A under (patho)physiological conditions. TL1A and DR3 are not only a driving force in the development of autoimmune and inflammatory diseases, but also play an important role in counteracting these processes through an increase in the number of regulatory T cells. Ligands of the tumor necrosis factor family typically occur in two forms, membrane-bound and soluble, that can differ strikingly with respect to their efficacy in activating their corresponding receptor(s). Ligand-based approaches to activate the TL1A-DR3 pathway therefore require understanding of the molecular prerequisites of TL1A-based DR3 activation. To date, this has not been addressed. Here, we show that recombinant soluble trimeric TL1A is fully sufficient to strongly activate DR3-associated pro- and anti-apoptotic signaling pathways. In contrast to the TRAIL death receptors, which are much better activated by soluble TRAIL upon secondary ligand oligomerization, but similarly to the death receptor tumor necrosis factor receptor 1, DR3 is efficiently activated by soluble TL1A trimers. Additionally, we have measured the affinity of TL1A-DR3 interaction in a cell-based system, and demonstrated TL1A-induced DR3 internalization. Identification of DR3 as a tumor necrosis factor receptor that responds to soluble ligand trimers without further oligomerization provides a basis for therapeutic exploitation of the TL1A-DR3 pathway. © 2015 FEBS.

Contribution of programmed cell death receptor (PD)-1 to Kupffer cell dysfunction in murine polymicrobial sepsis.

PubMed

Wang, Fei; Huang, Xin; Chung, Chun-Shiang; Chen, Yaping; Hutchins, Noelle A; Ayala, Alfred

2016-08-01

Recent studies suggest that coinhibitory receptors appear to be important in contributing sepsis-induced immunosuppression. Our laboratory reported that mice deficient in programmed cell death receptor (PD)-1 have increased bacterial clearance and improved survival in experimental sepsis induced by cecal ligation and puncture (CLP). In response to infection, the liver clears the blood of bacteria and produces cytokines. Kupffer cells, the resident macrophages in the liver, are strategically situated to perform the above functions. However, it is not known if PD-1 expression on Kupffer cells is altered by septic stimuli, let alone if PD-1 ligation contributes to the altered microbial handling seen. Here we report that PD-1 is significantly upregulated on Kupffer cells during sepsis. PD-1-deficient septic mouse Kupffer cells displayed markedly enhanced phagocytosis and restoration of the expression of major histocompatibility complex II and CD86, but reduced CD80 expression compared with septic wild-type (WT) mouse Kupffer cells. In response to ex vivo LPS stimulation, the cytokine productive capacity of Kupffer cells derived from PD-1-/- CLP mice exhibited a marked, albeit partial, restoration of the release of IL-6, IL-12, IL-1β, monocyte chemoattractant protein-1, and IL-10 compared with septic WT mouse Kupffer cells. In addition, PD-1 gene deficiency decreased LPS-induced apoptosis of septic Kupffer cells, as indicated by decreased levels of cleaved caspase-3 and reduced terminal deoxynucleotidyl transferase dUTP nick end-labeling-positive cells. Exploring the signal pathways involved, we found that, after ex vivo LPS stimulation, septic PD-1-/- mouse Kupffer cells exhibited an increased Akt phosphorylation and a reduced p38 phosphorylation compared with septic WT mouse Kupffer cells. Together, these results indicate that PD-1 appears to play an important role in regulating the development of Kupffer cell dysfunction seen in sepsis. Copyright © 2016 the

Contribution of programmed cell death receptor (PD)-1 to Kupffer cell dysfunction in murine polymicrobial sepsis

PubMed Central

Wang, Fei; Huang, Xin; Chung, Chun-Shiang; Chen, Yaping; Hutchins, Noelle A.

2016-01-01

Recent studies suggest that coinhibitory receptors appear to be important in contributing sepsis-induced immunosuppression. Our laboratory reported that mice deficient in programmed cell death receptor (PD)-1 have increased bacterial clearance and improved survival in experimental sepsis induced by cecal ligation and puncture (CLP). In response to infection, the liver clears the blood of bacteria and produces cytokines. Kupffer cells, the resident macrophages in the liver, are strategically situated to perform the above functions. However, it is not known if PD-1 expression on Kupffer cells is altered by septic stimuli, let alone if PD-1 ligation contributes to the altered microbial handling seen. Here we report that PD-1 is significantly upregulated on Kupffer cells during sepsis. PD-1-deficient septic mouse Kupffer cells displayed markedly enhanced phagocytosis and restoration of the expression of major histocompatibility complex II and CD86, but reduced CD80 expression compared with septic wild-type (WT) mouse Kupffer cells. In response to ex vivo LPS stimulation, the cytokine productive capacity of Kupffer cells derived from PD-1−/− CLP mice exhibited a marked, albeit partial, restoration of the release of IL-6, IL-12, IL-1β, monocyte chemoattractant protein-1, and IL-10 compared with septic WT mouse Kupffer cells. In addition, PD-1 gene deficiency decreased LPS-induced apoptosis of septic Kupffer cells, as indicated by decreased levels of cleaved caspase-3 and reduced terminal deoxynucleotidyl transferase dUTP nick end-labeling-positive cells. Exploring the signal pathways involved, we found that, after ex vivo LPS stimulation, septic PD-1−/− mouse Kupffer cells exhibited an increased Akt phosphorylation and a reduced p38 phosphorylation compared with septic WT mouse Kupffer cells. Together, these results indicate that PD-1 appears to play an important role in regulating the development of Kupffer cell dysfunction seen in sepsis. PMID:27288425

Cell death at the intestinal epithelial front line.

PubMed

Delgado, Maria Eugenia; Grabinger, Thomas; Brunner, Thomas

2016-07-01

The intestinal epithelium represents the largest epithelial surface in our body. This single-cell-layer epithelium mediates important functions in the absorption of nutrients and in the maintenance of barrier function, preventing luminal microorganisms from invading the body. Due to its constant regeneration the intestinal epithelium is a tissue not only with very high proliferation rates but also with very prominent physiological and pathophysiological cell death induction. The normal physiological differentiation and maturation of intestinal epithelial cells leads to their shedding and apoptotic cell death within a few days, without disturbing the epithelial barrier integrity. In contrast excessive intestinal epithelial cell death induced by irradiation, drugs and inflammation severely impairs the vital functions of this tissue. In this review we discuss cell death processes in the intestinal epithelium in health and disease, with special emphasis on cell death triggered by the tumour necrosis factor receptor family. © 2015 FEBS.

Contribution of TMEM16F to pyroptotic cell death.

PubMed

Ousingsawat, Jiraporn; Wanitchakool, Podchanart; Schreiber, Rainer; Kunzelmann, Karl

2018-02-20

Pyroptosis is a highly inflammatory form of programmed cell death that is caused by infection with intracellular pathogens and activation of canonical or noncanonical inflammasomes. The purinergic receptor P2X 7 is activated by the noncanonical inflammasome and contributes essentially to pyroptotic cell death. The Ca 2+ activated phospholipid scramblase and ion channel TMEM16F has been shown earlier to control cellular effects downstream of purinergic P2X 7 receptors that ultimately lead to cell death. As pyroptotic cell death is accompanied by an increases in intracellular Ca 2+ , we asked whether TMEM16F is activated during pyroptosis. The N-terminal cleavage product of gasdermin D (GD-N) is an executioner of pyroptosis by forming large plasma membrane pores. Expression of GD-N enhanced basal Ca 2+ levels and induced cell death. We observed that GD-N induced cell death in HEK293 and HAP1 cells, which was depending on expression of endogenous TMEM16F. GD-N activated large whole cell currents that were suppressed by knockdown or inhibition of TMEM16F. The results suggest that whole cell currents induced by the pore forming domain of gasdermin-D, are at least in part due to activation of TMEM16F. Knockdown of other TMEM16 paralogues expressed in HAP1 cells suggest TMEM16F as a crucial element during pyroptosis and excluded a role of other TMEM16 proteins. Thus TMEM16F supports pyroptosis and other forms of inflammatory cell death such as ferroptosis. Its potent inhibition by tannic acid may be part of the anti-inflammatory effects of flavonoids.

Critical Involvement of Extracellular ATP Acting on P2RX7 Purinergic Receptors in Photoreceptor Cell Death

PubMed Central

Notomi, Shoji; Hisatomi, Toshio; Kanemaru, Takaaki; Takeda, Atsunobu; Ikeda, Yasuhiro; Enaida, Hiroshi; Kroemer, Guido; Ishibashi, Tatsuro

2011-01-01

Stressed cells release ATP, which participates in neurodegenerative processes through the specific ligation of P2RX7 purinergic receptors. Here, we demonstrate that extracellular ATP and the more specific P2RX7 agonist, 2′- and 3′-O-(4-benzoylbenzoyl)-ATP, both induce photoreceptor cell death when added to primary retinal cell cultures or when injected into the eyes from wild-type mice, but not into the eyes from P2RX7−/− mice. Photoreceptor cell death was accompanied by the activation of caspase-8 and -9, translocation of apoptosis-inducing factor from mitochondria to nuclei, and TUNEL-detectable chromatin fragmentation. All hallmarks of photoreceptor apoptosis were prevented by premedication or co-application of Brilliant Blue G, a selective P2RX7 antagonist that is already approved for the staining of internal limiting membranes during ocular surgery. ATP release is up-regulated by nutrient starvation in primary retinal cell cultures and seems to be an initializing event that triggers primary and/or secondary cell death via the positive feedback loop on P2RX7. Our results encourage the potential application of Brilliant Blue G as a novel neuroprotective agent in retinal diseases or similar neurodegenerative pathologies linked to excessive extracellular ATP. PMID:21983632

Cyproterone acetate enhances TRAIL-induced androgen-independent prostate cancer cell apoptosis via up-regulation of death receptor 5.

PubMed

Chen, Linjie; Wolff, Dennis W; Xie, Yan; Lin, Ming-Fong; Tu, Yaping

2017-03-07

Virtually all prostate cancer deaths occur due to obtaining the castration-resistant phenotype after prostate cancer cells escaped from apoptosis and/or growth suppression initially induced by androgen receptor blockade. TNF-related apoptosis-inducing ligand (TRAIL) was an attractive cancer therapeutic agent due to its minimal toxicity to normal cells and remarkable apoptotic activity in tumor cells. However, most localized cancers including prostate cancer are resistant to TRAIL-induced apoptosis, thereby creating a therapeutic challenge of inducing TRAIL sensitivity in cancer cells. Herein the effects of cyproterone acetate, an antiandrogen steroid, on the TRAIL-induced apoptosis of androgen receptor-negative prostate cancer cells are reported. Cell apoptosis was assessed by both annexin V/propidium iodide labeling and poly (ADP-ribose) polymerase cleavage assays. Gene and protein expression changes were determined by quantitative real-time PCR and western blot assays. The effect of cyproterone acetate on gene promoter activity was determined by luciferase reporter assay. Cyproterone acetate but not AR antagonist bicalutamide dramatically increased the susceptibility of androgen receptor-negative human prostate cancer PC-3 and DU145 cells to TRAIL-induced apoptosis but no effects on immortalized human prostate stromal PS30 cells and human embryonic kidney HEK293 cells. Further investigation of the TRAIL-induced apoptosis pathway revealed that cyproterone acetate exerted its effect by selectively increasing death receptor 5 (DR5) mRNA and protein expression. Cyproterone acetate treatment also increased DR5 gene promoter activity, which could be abolished by mutation of a consensus binding domain of transcription factor CCAAT-enhancer-binding protein homologous protein (CHOP) in the DR5 gene promoter. Cyproterone acetate increases CHOP expression in a concentration and time-dependent manner and endoplasmic reticulum stress reducer 4-phenylbutyrate could block

Lysosomal Membrane Permeabilization is an Early Event in Sigma-2 Receptor Ligand Mediated Cell Death in Pancreatic Cancer

PubMed Central

2012-01-01

Background Sigma-2 receptor ligands have been studied for treatment of pancreatic cancer because they are preferentially internalized by proliferating cells and induce apoptosis. This mechanism of apoptosis is poorly understood, with varying reports of caspase-3 dependence. We evaluated multiple sigma-2 receptor ligands in this study, each shown to decrease tumor burden in preclinical models of human pancreatic cancer. Results Fluorescently labeled sigma-2 receptor ligands of two classes (derivatives of SW43 and PB282) localize to cell membrane components in Bxpc3 and Aspc1 pancreatic cancer cells and accumulate in lysosomes. We found that interactions in the lysosome are critical for cell death following sigma-2 ligand treatment because selective inhibition of a protective lysosomal membrane glycoprotein, LAMP1, with shRNA greatly reduced the viability of cells following treatment. Sigma-2 ligands induced lysosomal membrane permeabilization (LMP) and protease translocation triggering downstream effectors of apoptosis. Subsequently, cellular oxidative stress was greatly increased following treatment with SW43, and the hydrophilic antioxidant N-acetylcysteine (NAC) gave greater protection against this than a lipophilic antioxidant, α-tocopherol (α-toco). Conversely, PB282-mediated cytotoxicity relied less on cellular oxidation, even though α-toco did provide protection from this ligand. In addition, we found that caspase-3 induction was not as significantly inhibited by cathepsin inhibitors as by antioxidants. Both NAC and α-toco protected against caspase-3 induction following PB282 treatment, while only NAC offered protection following SW43 treatment. The caspase-3 inhibitor DEVD-FMK offered significant protection from PB282, but not SW43. Conclusions Sigma-2 ligand SW43 commits pancreatic cancer cells to death by a caspase-independent process involving LMP and oxidative stress which is protected from by NAC. PB282 however undergoes a caspase-dependent death

K6 linked polyubiquitylation of FADD by CHIP prevents death inducing signaling complex formation suppressing cell death.

PubMed

Seo, Jinho; Lee, Eun-Woo; Shin, Jihye; Seong, Daehyeon; Nam, Young Woo; Jeong, Manhyung; Lee, Seon-Hyeong; Lee, Cheolju; Song, Jaewhan

2018-05-23

Fas-associated death domain (FADD) is an adaptor protein recruiting complexes of caspase 8 to death ligand receptors to induce extrinsic apoptotic cell death in response to a TNF superfamily member. Although, formation of the complex of FADD and caspase 8 upon death stimuli has been studied in detail, posttranslational modifications fine-tuning these processes have yet to be identified. Here we revealed that K6-linked polyubiquitylation of FADD on lysines 149 and 153 mediated by C terminus HSC70-interacting protein (CHIP) plays an important role in preventing formation of the death inducing signaling complex (DISC), thus leading to the suppression of cell death. Cells depleted of CHIP showed higher sensitivity toward death ligands such as FasL and TRAIL, leading to upregulation of DISC formation composed of a death receptor, FADD, and caspase 8. CHIP was able to bind to FADD, induce K6-linked polyubiquitylation of FADD, and suppress DISC formation. By mass spectrometry, lysines 149 and 153 of FADD were found to be responsible for CHIP-mediated FADD ubiquitylation. FADD mutated at these sites was capable of more potent cell death induction as compared with the wild type and was no longer suppressed by CHIP. On the other hand, CHIP deficient in E3 ligase activity was not capable of suppressing FADD function and of FADD ubiquitylation. CHIP depletion in ME-180 cells induced significant sensitization of these cells toward TRAIL in xenograft analyses. These results imply that K6-linked ubiquitylation of FADD by CHIP is a crucial checkpoint in cytokine-dependent extrinsic apoptosis.

Clonidine Induces Apoptosis of Human Corneal Epithelial Cells through Death Receptors-Mediated, Mitochondria-Dependent Signaling Pathway.

PubMed

Fan, Dan; Fan, Ting-Jun

2017-03-01

Clonidine, an α2-adrenoreceptor agonist, is an anti-glaucoma drug clinically used in many developing countries, and its abuse might damage the cornea and impair human vision. However, its cytotoxicity and precise mechanisms need to be elucidated. Herein, we investigated the cytotoxicity of clonidine and its underlying mechanisms, using an in vitro model of human corneal epithelial (HCEP) cells and an in vivo model of cat corneas, respectively. HCEP cells were treated with various doses of clonidine for 1-28 h, resulting in abnormal morphology, decline of cell viability and G1 phase arrest in a time- and/or dose-dependent manner. Moreover, clonidine treatment induced elevation of plasma membrane permeability, phosphatidylserine externalization, DNA fragmentation, and apoptotic body formation in HCEP cells. Furthermore, we found that clonidine treatment resulted in activated caspase-2, -3, -8, and -9, disruption of the mitochondrial transmembrane potential, downregulation of Bcl-2, and upregulation of Bad, cytoplasmic cytochrome c and apoptosis inducing factor, suggesting that clonidine-induced apoptosis is triggered through Fas/TNFR1 death receptors and Bcl-2 family proteins-mediated mitochondria-dependent pathways. Finally, our in vivo results displayed that 0.25% clonidine could induce DNA fragmentation of cat corneal epithelial cells. In summary, our findings suggest that clonidine above 1/32 of its clinical therapeutic dosage is cytotoxic to corneal epithelial cells by inducing cell apoptosis both in vitro and in vivo, and its pro-apoptotic effect on HCEP cells is triggered by a Fas/TNFR1 death receptors-mediated, mitochondria-dependent signaling pathway. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Fas-associated Protein with Death Domain (FADD)-independent Recruitment of c-FLIPL to Death Receptor 5*

PubMed Central

Jin, Tai-Guang; Kurakin, Alexei; Benhaga, Nordine; Abe, Karon; Mohseni, Mehrdad; Sandra, Ferry; Song, Keli; Kay, Brian K.; Khosravi-Far, Roya

2010-01-01

Here we show a novel mechanism by which FLICE-like inhibitory protein (c-FLIP) regulates apoptosis induced by tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and one of its receptors, DR5. c-FLIP is a critical regulator of the TNF family of cytokine receptor signaling. c-FLIP has been postulated to prevent formation of the competent death-inducing signaling complex (DISC) in a ligand-dependent manner, through its interaction with FADD and/or caspase-8. In order to identify regulators of TRAIL function, we used the intracellular death domain (DD) of DR5 as a target to screen a phage-displayed combinatorial peptide library. The DD of DR5 selected from the library a peptide that showed sequence similarity to a stretch of amino acids in the C terminus of c-FLIPL. The phage-displayed peptide selectively interacted with the DD of DR5 in in vitro binding assays. Similarly, full-length c-FLIP (c-FLIPL) and the C-terminal p12 domain of c-FLIP interacted with DR5 both in in vitro pull-down assays and in mammalian cells. This interaction was independent of TRAIL. To the contrary, TRAIL treatment released c-FLIPL from DR5, permitting the recruitment of FADD to the active DR5 signaling complex. By employing FADD-deficient Jurkat cells, we demonstrate that DR5 and c-FLIPL interact in a FADD-independent manner. Moreover, we show that a cellular membrane permeable version of the peptide corresponding to the DR5 binding domain of c-FLIP induces apoptosis in mammalian cells. Taken together, these findings indicate that c-FLIPL interacts with the DD of DR5, thus preventing death signaling by DR5 prior to the formation of an active DISC. Because TRAIL and DR5 are ubiquitously expressed, the interaction of c-FLIPL and DR5 indicates a mechanism by which tumor selective apoptosis can be achieved through protecting normal cells from undergoing death receptor-induced apoptosis. PMID:15485835

Death receptor Fas (CD95) signaling in the central nervous system: tuning neuroplasticity?

PubMed

Reich, Arno; Spering, Christopher; Schulz, Jörg B

2008-09-01

For over a decade, neuroscientific research has focused on processes of apoptosis and its contribution to the pathophysiology of neurological diseases. In the central nervous system, the degree of intrinsic mitochondrial-mediated apoptotic signaling expresses a cell's individual metabolic stress, whereas activation of the extrinsic death receptor-induced cascade is regarded as a sign of imbalanced cellular networks. Under physiological conditions, most neurons possess death receptors without being sensitive to receptor-mediated apoptosis. This paradox raises two questions: what is the evolutionary advantage of expressing potentially harmful proteins? How is their signaling controlled? This review summarizes the functional relevance of FasL-Fas signaling--a quintessential death ligand/receptor system--in different neurological disease models ranging from traumatic, inflammatory and ischemic to neurodegenerative processes. Furthermore, it outlines alternative non-apoptotic Fas signaling, shedding new light on its neuroplastic capacity. Finally, receptor-proximal regulatory proteins are introduced and identified as potential protagonists of disease-modifying neurological therapies.

17-beta estradiol inhibits oxidative stress-induced accumulation of AIF into nucleolus and PARP1-dependent cell death via estrogen receptor alpha.

PubMed

Batnasan, Enkhzaya; Wang, Ruoxi; Wen, Jitao; Ke, Yueshuang; Li, Xiaoxue; Bohio, Ameer Ali; Zeng, Xianlu; Huo, Hongliang; Han, Liping; Boldogh, Istvan; Ba, Xueqing

2015-01-05

Oxidative stress-induced DNA damage results in over-activation of poly(ADP-ribose) polymerase 1 (PARP1), leading to parthanatos, a newly discovered cell elimination pathway. Inhibition of PARP1-dependent cell death has shown to improve the outcome of diseases, including stroke, heart ischemia, and neurodegenerative diseases. In the present study we aimed to detect whether estrogen plays a protective role in inhibiting parthanatos. We utilized human mammary adenocarcinoma cells (MCF7) that abundantly express the estrogen receptor alpha and beta (ERα and ERβ). Parthanatos was induced by challenging the cells with hydrogen peroxide (H2O2). Microscopic imaging and molecular biological techniques, such as Western blot analysis and RNA interference, were performed. The results showed 17β estradiol (E2) protected MCF7 cells from PARP1-dependent cell death by decreasing protein PARylation, and AIF translocation into nuclei/nucleoli. Down-regulation of ERα expression by siRNA before E2 addition resulted in the failure of the E2-mediated inhibition of H2O2-induced protein PARylation and AIF nucleolar translocation. Together these data suggest that estrogen via its alpha-type receptor inhibits oxidative stress-induced, PARP1-dependent cell death. The present study provided us insight into how to apply hormone therapy in intervention of parthanatos-implicated ischemic and degenerative diseases. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Critical involvement of extracellular ATP acting on P2RX7 purinergic receptors in photoreceptor cell death.

PubMed

Notomi, Shoji; Hisatomi, Toshio; Kanemaru, Takaaki; Takeda, Atsunobu; Ikeda, Yasuhiro; Enaida, Hiroshi; Kroemer, Guido; Ishibashi, Tatsuro

2011-12-01

Stressed cells release ATP, which participates in neurodegenerative processes through the specific ligation of P2RX7 purinergic receptors. Here, we demonstrate that extracellular ATP and the more specific P2RX7 agonist, 2'- and 3'-O-(4-benzoylbenzoyl)-ATP, both induce photoreceptor cell death when added to primary retinal cell cultures or when injected into the eyes from wild-type mice, but not into the eyes from P2RX7(-/-) mice. Photoreceptor cell death was accompanied by the activation of caspase-8 and -9, translocation of apoptosis-inducing factor from mitochondria to nuclei, and TUNEL-detectable chromatin fragmentation. All hallmarks of photoreceptor apoptosis were prevented by premedication or co-application of Brilliant Blue G, a selective P2RX7 antagonist that is already approved for the staining of internal limiting membranes during ocular surgery. ATP release is up-regulated by nutrient starvation in primary retinal cell cultures and seems to be an initializing event that triggers primary and/or secondary cell death via the positive feedback loop on P2RX7. Our results encourage the potential application of Brilliant Blue G as a novel neuroprotective agent in retinal diseases or similar neurodegenerative pathologies linked to excessive extracellular ATP. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Mitochondrial calcium uniporter silencing potentiates caspase-independent cell death in MDA-MB-231 breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curry, Merril C.; Peters, Amelia A.; Kenny, Paraic A.

Highlights: •Some clinical breast cancers are associated with MCU overexpression. •MCU silencing did not alter cell death initiated with the Bcl-2 inhibitor ABT-263. •MCU silencing potentiated caspase-independent cell death initiated by ionomycin. •MCU silencing promoted ionomycin-mediated cell death without changes in bulk Ca{sup 2+}. -- Abstract: The mitochondrial calcium uniporter (MCU) transports free ionic Ca{sup 2+} into the mitochondrial matrix. We assessed MCU expression in clinical breast cancer samples using microarray analysis and the consequences of MCU silencing in a breast cancer cell line. Our results indicate that estrogen receptor negative and basal-like breast cancers are characterized by elevated levelsmore » of MCU. Silencing of MCU expression in the basal-like MDA-MB-231 breast cancer cell line produced no change in proliferation or cell viability. However, distinct consequences of MCU silencing were seen on cell death pathways. Caspase-dependent cell death initiated by the Bcl-2 inhibitor ABT-263 was not altered by MCU silencing; whereas caspase-independent cell death induced by the calcium ionophore ionomycin was potentiated by MCU silencing. Measurement of cytosolic Ca{sup 2+} levels showed that the promotion of ionomycin-induced cell death by MCU silencing occurs independently of changes in bulk cytosolic Ca{sup 2+} levels. This study demonstrates that MCU overexpression is a feature of some breast cancers and that MCU overexpression may offer a survival advantage against some cell death pathways. MCU inhibitors may be a strategy to increase the effectiveness of therapies that act through the induction of caspase-independent cell death pathways in estrogen receptor negative and basal-like breast cancers.« less

Glutamine-mediated protection from neuronal cell death depends on mitochondrial activity.

PubMed

Stelmashook, E V; Lozier, E R; Goryacheva, E S; Mergenthaler, P; Novikova, S V; Zorov, D B; Isaev, N K

2010-09-27

The specific aim of this study was to elucidate the role of mitochondria in a neuronal death caused by different metabolic effectors and possible role of intracellular calcium ions ([Ca(2+)](i)) and glutamine in mitochondria- and non-mitochondria-mediated cell death. Inhibition of mitochondrial complex I by rotenone was found to cause intensive death of cultured cerebellar granule neurons (CGNs) that was preceded by an increase in intracellular calcium concentration ([Ca(2+)](i)). The neuronal death induced by rotenone was significantly potentiated by glutamine. In addition, inhibition of Na/K-ATPase by ouabain also caused [Ca(2+)](i) increase, but it induced neuronal cell death only in the absence of glucose. Treatment with glutamine prevented the toxic effect of ouabain and decreased [Ca(2+)](i). Blockade of ionotropic glutamate receptors prevented neuronal death and significantly decreased [Ca(2+)](i), demonstrating that toxicity of rotenone and ouabain was at least partially mediated by activation of these receptors. Activation of glutamate receptors by NMDA increased [Ca(2+)](i) and decreased mitochondrial membrane potential leading to markedly decreased neuronal survival under glucose deprivation. Glutamine treatment under these conditions prevented cell death and significantly decreased the disturbances of [Ca(2+)](i) and changes in mitochondrial membrane potential caused by NMDA during hypoglycemia. Our results indicate that glutamine stimulates glutamate-dependent neuronal damage when mitochondrial respiration is impaired. However, when mitochondria are functionally active, glutamine can be used by mitochondria as an alternative substrate to maintain cellular energy levels and promote cell survival. (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Targeting death receptors to fight cancer: from biological rational to clinical implementation.

PubMed

Mocellin, S

2010-01-01

Considering that most currently available chemotherapeutic drugs work by inducing cell apoptosis, it is not surprising that many expectations in cancer research come from the therapeutic exploitation of the naturally occurring death pathways. Receptor mediated apoptosis depends upon the engagement of specific ligands with their respective membrane receptors and - within the frame of complex regulatory networks - modulates some key physiological and pathological processes such as lymphocyte survival, inflammation and infectious diseases. A pivotal observation was that some of these pathways may be over activated in cancer under particular circumstances, which opened the avenue for tumor-specific therapeutic interventions. Although one death-related ligand (e.g., tumor necrosis factor, TNF) is currently the basis of effective anticancer regimens in the clinical setting, the systemic toxicity is hampering its wide therapeutic exploitation. However, strategies to split the therapeutic from the toxic TNF activity are being devised. Furthermore, other death receptor pathways (e.g., Fas/FasL, TRAIL/TRAIL receptor) are being intensively investigated in order to therapeutically exploit their activity against cancer. This article summarizes the current knowledge on the molecular features of death receptor pathways that make them an attractive target for anticancer therapeutics. In addition, the results so far obtained in the clinical oncology setting as well as the issues to be faced while interfering with these pathways for therapeutic purposes will be overviewed.

Group I mGlu receptor stimulation inhibits activation-induced cell death of human T lymphocytes

PubMed Central

Chiocchetti, Annalisa; Miglio, Gianluca; Mesturini, Riccardo; Varsaldi, Federica; Mocellin, Marco; Orilieri, Elisabetta; Dianzani, Chiara; Fantozzi, Roberto; Dianzani, Umberto; Lombardi, Grazia

2006-01-01

The effects of L-glutamate on activation-induced cell death (AICD) of human activated (1 μg ml−1 phytohemagglutinin plus 2 U ml−1 interleukin-2; 8 days) T lymphocytes were studied by measuring anti-CD3 monoclonal antibody (10 μg ml−1; 18 h)-induced cell apoptosis (Annexin V and propidium iodide staining). L-Glutamate (1 × 10−8–1 × 10−4 M) significantly (P⩽0.01) inhibited AICD in a concentration-dependent manner (EC50=6.3 × 10−8 M; maximum inhibition 54.8±6.3% at 1 × 10−6 M). The L-glutamate inhibitory effect was pharmacologically characterized as mediated by group I mGlu receptors, since mGlu receptor agonists reproduced this effect. The EC50 values were: 3.2 × 10−7 M for (1S,3R)-ACPD; 4.5 × 10−8 M for quisqualate; 1.0 × 10−6 M for (S)-3,5-DHPG; 2.0 × 10−5 M for CHPG. Group I mGlu receptor antagonists inhibited the effects of quisqualate 1.0 × 10−6 M. The IC50 values calculated were: 8.7 × 10−5, 4.3 × 10−6 and 6.3 × 10−7 M for AIDA, LY 367385 and MPEP, respectively. L-Glutamate (1 × 10−6 M; 18 h) significantly (P⩽0.05) inhibited FasL expression (40.8±11.3%) (cytofluorimetric analysis), whereas it did not affect Fas signalling. Expression of both mGlu1 and mGlu5 receptor mRNA by T lymphocytes and T-cell lines, as demonstrated by reverse transcriptase–PCR analysis, suggests that L-glutamate-mediated inhibition of AICD was exerted on T cells. These data depict a novel role for L-glutamate in the regulation of the immune response through group I mGlu receptor-mediated mechanisms. PMID:16751798

TRAF2 multitasking in TNF receptor-induced signaling to NF-κB, MAP kinases and cell death.

PubMed

Borghi, Alice; Verstrepen, Lynn; Beyaert, Rudi

2016-09-15

Tumor Necrosis Factor (TNF) is a potent inflammatory cytokine that exerts its functions through the activation of two distinct receptors, TNFR1 and TNFR2. Both receptors can activate canonical NF-κB and JNK MAP kinase signaling, while TNFR2 can also activate non-canonical NF-κB signaling, leading to numerous changes in gene expression that drive inflammation, cell proliferation and cell survival. On the other hand, TNFR1 also activates signaling pathways leading to cell death by either apoptosis or necroptosis, depending on the cellular context. A key player in TNFR1- and TNFR2-induced signaling is the RING finger protein TRAF2, which is recruited to both receptors upon their stimulation. TRAF2 exerts multiple receptor-specific functions but also mediates cross-talk between TNFR1 and TNFR2, dictating the outcome of TNF stimulation. In this review, we provide an overview of the positive and negative regulatory role of TRAF2 in different TNFR1 and TNFR2 signaling pathways. We discuss the underlying molecular mechanism of action, distinguishing between TRAF2 scaffold and E3 ubiquitin ligase functions, and the regulation of TRAF2 by specific post-translational modifications. Finally, we elaborate on some possible strategies to modulate TRAF2 function in the context of therapeutic targeting in autoimmunity and cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Over-expression of angiotensin II type 2 receptor gene induces cell death in lung adenocarcinoma cells.

PubMed

Pickel, Lara; Matsuzuka, Takaya; Doi, Chiyo; Ayuzawa, Rie; Maurya, Dharmendra Kumar; Xie, Sheng-Xue; Berkland, Cory; Tamura, Masaaki

2010-02-01

The endogenous angiotensin II (Ang II) type 2 receptor (AT 2) has been shown to mediate apoptosis in cardiovascular tissues. Thus, the aim of this study was to explore the anti-cancer effect of AT 2 over-expression on lung adenocarcinoma cells in vitro using adenoviral (Ad), FuGENE, and nanoparticle vectors. All three gene transfection methods efficiently transfected AT 2 cDNA into lung cancer cells but caused minimal gene transfection in normal lung epithelial cells. Ad-AT 2 significantly attenuated multiple human lung cancer cell growth (A549 and H358) as compared to the control viral vector, Ad-LacZ, when cell viability was examined by direct cell count. Examination of annexin V by flow cytometry revealed the activation of the apoptotic pathway via AT 2 over-expression. Western Blot analysis confirmed the activation of caspase-3. Similarly, poly (lactide-co-glycolic acid) (PLGA) biodegradable nanoparticles encapsulated AT 2 plasmid DNA were shown to be effectively taken up into the lung cancer cell. Nanoparticle-based AT 2 gene transfection markedly increased AT 2 expression and resultant cell death in A549 cells. These results indicate that AT 2 over-expression effectively attenuates growth of lung adenocarcinoma cells through intrinsic apoptosis. Our results also suggest that PLGA nanoparticles can be used as an efficient gene delivery vector for lung adenocarcinoma targeted therapy.

Differential Induction of Immunogenic Cell Death and Interferon Expression in Cancer Cells by Structured ssRNAs.

PubMed

Lee, Jaewoo; Lee, Youngju; Xu, Li; White, Rebekah; Sullenger, Bruce A

2017-06-07

Activation of the RNA-sensing pattern recognition receptor (PRR) in cancer cells leads to cell death and cytokine expression. This cancer cell death releases tumor antigens and damage-associated molecular patterns (DAMPs) that induce anti-tumor immunity. However, these cytokines and DAMPs also cause adverse inflammatory and thrombotic complications that can limit the overall therapeutic benefits of PRR-targeting anti-cancer therapies. To overcome this problem, we generated and evaluated two novel and distinct ssRNA molecules (immunogenic cell-killing RNA [ICR]2 and ICR4). ICR2 and ICR4 differentially stimulated cell death and PRR signaling pathways and induced different patterns of cytokine expression in cancer and innate immune cells. Interestingly, DAMPs released from ICR2- and ICR4-treated cancer cells had distinct patterns of stimulation of innate immune receptors and coagulation. Finally, ICR2 and ICR4 inhibited in vivo tumor growth as effectively as poly(I:C). ICR2 and ICR4 are potential therapeutic agents that differentially induce cell death, immune stimulation, and coagulation when introduced into tumors. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Gingerol sensitizes TRAIL-induced apoptotic cell death of glioblastoma cells

PubMed Central

Lee, Dae-Hee; Kim, Dong-Wook; Jung, Chang-Hwa; Lee, Yong J.; Park, Daeho

2014-01-01

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 ginger can induce TRAIL-mediated apoptosis of glioblastoma. Gingerol increased death receptor (DR) 5 levels in a p53-dependent manner. Furthermore, gingerol decreased the expression level of anti-apoptotic proteins (survivin, c-FLIP, Bcl-2, and XIAP) and increased pro-apoptotic protein, Bax and truncate Bid, by generating reactive oxygen species (ROS).We also found that the sensitizing effects of gingerol in TRAIL-induced cell death were blocked by scavenging ROS or overexpressing anti-apoptotic protein (Bcl-2). Therefore, we showed the functions of gingerol as a sensitizing agent to induce cell death of TRAIL-resistant glioblastoma cells. This study gives rise to the possibility of applying gingerol as an anti-tumor agent that can be used for the purpose of combination treatment with TRAIL in TRAIL-resistant glioblastoma tumor therapy. PMID:25034532

Nuclear DAMP complex-mediated RAGE-dependent macrophage cell death

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Ruochan; Department of Infectious Diseases and State Key Lab of Viral Hepatitis, Xiangya Hospital, Central South University, Changsha, Hunan 410008; Fu, Sha

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

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

Targeting breast to brain metastatic tumours with death receptor ligand expressing therapeutic stem cells

PubMed Central

Bagci-Onder, Tugba; Du, Wanlu; Figueiredo, Jose-Luiz; Martinez-Quintanilla, Jordi

2015-01-01

Characterizing clinically relevant brain metastasis models and assessing the therapeutic efficacy in such models are fundamental for the development of novel therapies for metastatic brain cancers. In this study, we have developed an in vivo imageable breast-to-brain metastasis mouse model. Using real time in vivo imaging and subsequent composite fluorescence imaging, we show a widespread distribution of micro- and macro-metastasis in different stages of metastatic progression. We also show extravasation of tumour cells and the close association of tumour cells with blood vessels in the brain thus mimicking the multi-foci metastases observed in the clinics. Next, we explored the ability of engineered adult stem cells to track metastatic deposits in this model and show that engineered stem cells either implanted or injected via circulation efficiently home to metastatic tumour deposits in the brain. Based on the recent findings that metastatic tumour cells adopt unique mechanisms of evading apoptosis to successfully colonize in the brain, we reasoned that TNF receptor superfamily member 10A/10B apoptosis-inducing ligand (TRAIL) based pro-apoptotic therapies that induce death receptor signalling within the metastatic tumour cells might be a favourable therapeutic approach. We engineered stem cells to express a tumour selective, potent and secretable variant of a TRAIL, S-TRAIL, and show that these cells significantly suppressed metastatic tumour growth and prolonged the survival of mice bearing metastatic breast tumours. Furthermore, the incorporation of pro-drug converting enzyme, herpes simplex virus thymidine kinase, into therapeutic S-TRAIL secreting stem cells allowed their eradication post-tumour treatment. These studies are the first of their kind that provide insight into targeting brain metastasis with stem-cell mediated delivery of pro-apoptotic ligands and have important clinical implications. PMID:25910782

Characterization of the Interactions between Calmodulin and Death Receptor 5 in Triple-negative and Estrogen Receptor-positive Breast Cancer Cells

PubMed Central

Fancy, Romone M.; Wang, Lingyun; Zeng, Qinghua; Wang, Hong; Zhou, Tong; Buchsbaum, Donald J.; Song, Yuhua

2016-01-01

Activation of death receptor-5 (DR5) leads to the formation of death inducing signaling complex (DISC) for apoptotic signaling. Targeting DR5 to induce breast cancer apoptosis is a promising strategy to circumvent drug resistance and present a target for breast cancer treatment. Calmodulin (CaM) has been shown to regulate DR5-mediated apoptotic signaling, however, its mechanism remains unknown. In this study, we characterized CaM and DR5 interactions in breast cancer cells with integrated experimental and computational approaches. Results show that CaM directly binds to DR5 in a calcium dependent manner in breast cancer cells. The direct interaction of CaM with DR5 is localized at DR5 death domain. We have predicted and verified the CaM-binding site in DR5 being 354WEPLMRKLGL363 that is located at the α2 helix and the loop between α2 helix and α3 helix of DR5 DD. The residues of Trp-354, Arg-359, Glu-355, Leu-363, and Glu-367 in DR5 death domain that are important for DR5 recruitment of FADD and caspase-8 for DISC formation to signal apoptosis also play an important role for CaM-DR5 binding. The changed electrostatic potential distribution in the CaM-binding site in DR5 DD by the point mutations of W354A, E355K, R359A, L363N, or E367K in DR5 DD could directly contribute to the experimentally observed decreased CaM-DR5 binding by the point mutations of the key residues in DR5 DD. Results from this study provide a key step for the further investigation of the role of CaM-DR5 binding in DR5-mediated DISC formation for apoptosis in breast cancer cells. PMID:27129269

Tumor necrosis factor-α inhibits effects of aryl hydrocarbon receptor ligands on cell death in human lymphocytes.

PubMed

Ghatrehsamani, Mahdi; Soleimani, Masoud; Esfahani, Behjat A Moayedi; Shirzad, Hedayatollah; Hakemi, Mazdak G; Mossahebimohammadi, Majid; Eskandari, Nahid; Adib, Minoo

2015-01-01

Activation of aryl hydrocarbon receptor (AhR) leads to diverse outcome in various kinds of cells. AhR activation may induce apoptosis or prevent of apoptosis and cell death. Recent studies suggest that apoptosis effects of AhR can be modulated by inflammatory cytokine like tumor necrosis factor alpha (TNF-α). In this study, we try to investigate the possible interaction of TNF-α with the 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), a ligand of AhR, on peripheral lymphocytes. Human peripheral blood mononuclear cells (PBMCs) were isolated from peripheral blood by discontinuous density gradient centrifugation on ficoll. Isolated PBMCs were divided into four groups: Control group, TNF-α administered group, TCDD administered group, co-administered group with TCDD and TNF-α. Cells were maintained for a week in lymphocyte culture condition. Then, TNF-α was added to group 2 and 4. Finally, apoptosis and necrosis were analyzed in all samples using flowcytometry. In group 4, the mean percent of necrosis and apoptosis in TCDD treatment groups was significantly larger than other groups; (P < 0.05). Furthermore, there was no significant difference between the mean percent of cell death in TNF-α administered group and TCDD administered group (P > 0.05). However, the mean percent of cell death in co-administered group with TCDD and TNF-α was significantly lower than other groups; (P < 0.05). TNF-α could significantly inhibit effects of TCDD on lymphocytes apoptosis. Combination effects of TNF-α and TCDD on lymphocyte increase cell survival.

Anti-cancer effect of bee venom toxin and melittin in ovarian cancer cells through induction of death receptors and inhibition of JAK2/STAT3 pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jo, Miran; Park, Mi Hee; Kollipara, Pushpa Saranya

We investigated whether bee venom and melittin, a major component of bee venom, inhibit cell growth through enhancement of death receptor expressions in the human ovarian cancer cells, SKOV3 and PA-1. Bee venom (1–5 μg/ml) and melittin (0.5–2 μg/ml) inhibited the growth of SKOV3 and PA-1 ovarian cancer cells by the induction of apoptotic cell death in a dose dependent manner. Consistent with apoptotic cell death, expression of death receptor (DR) 3 and DR6 was increased in both cancer cells, but expression of DR4 was increased only in PA-1 cells. Expression of DR downstream pro-apoptotic proteins including caspase-3, 8, andmore » Bax was concomitantly increased, but the phosphorylation of JAK2 and STAT3 and the expression of Bcl-2 were inhibited by treatment with bee venom and melittin in SKOV3 and PA-1 cells. Expression of cleaved caspase-3 was increased in SKOV3, but cleaved caspase-8 was increased in PA-1 cells. Moreover, deletion of DR3, DR4, and DR6 by small interfering RNA significantly reversed bee venom and melittin-induced cell growth inhibitory effect as well as down regulation of STAT3 by bee venom and melittin in SKOV3 and PA-1 ovarian cancer cell. These results suggest that bee venom and melittin induce apoptotic cell death in ovarian cancer cells through enhancement of DR3, DR4, and DR6 expression and inhibition of STAT3 pathway. -- Highlights: ► Some studies have showed that bee venom and/or melittin have anti-cancer effects. ► We found that bee venom and melittin inhibited cell growth in ovarian cancer cells. ► Bee venom and melittin induce apoptosis in SKOV3 and PA-1.« less

Receptor-interacting protein kinases modulate noise-induced sensory hair cell death

PubMed Central

Zheng, H-W; Chen, J; Sha, S-H

2014-01-01

Receptor-interacting protein (RIP) kinases promote the induction of necrotic cell death pathways. Here we investigated signaling pathways in outer hair cells (OHCs) of adult male CBA/J mice exposed to noise that causes permanent threshold shifts, with a particular focus on RIP kinase-regulated necroptosis. One hour after noise exposure, nuclei of OHCs in the basal region of the cochlea displayed both apoptotic and necrotic features. RIP1 and RIP3 protein levels increased and caspase-8 was activated. Treatment with pan-caspase inhibitor ZVAD blocked the activation of caspase-8 and reduced the number of apoptotic nuclei, while increasing levels of RIP1, RIP3, and necrotic OHCs. Conversely, treatment with necrosis inhibitor necrostatin-1 (Nec-1) or RIP3 siRNA (siRIP3) diminished noise-induced increases in RIP1 and RIP3, and decreased necrotic OHC nuclei. This treatment also increased the number of apoptotic nuclei without increasing activation of caspase-8. Consistent with the elevation of levels of RIP1 and RIP3, noise-induced active AMPKα levels increased with ZVAD treatment, but decreased with Nec-1 and siRIP3 treatment. Furthermore, treatment with siRIP3 did not alter the activation of caspase-8, but instead increased activation of caspase-9 and promoted endonuclease G translocation into OHC nuclei. Finally, auditory brainstem response functional measurements and morphological assessment of OHCs showed that ZVAD treatment reduces noise-induced deficits. This protective function is potentiated when combined with siRIP3 treatment. In conclusion, noise-induced OHC apoptosis and necrosis are modulated by caspases and RIP kinases, respectively. Inhibition of either pathway shifts the prevalence of OHC death to the alternative pathway. PMID:24874734

Cylindromatosis mediates neuronal cell death in vitro and in vivo.

PubMed

Ganjam, Goutham K; Terpolilli, Nicole Angela; Diemert, Sebastian; Eisenbach, Ina; Hoffmann, Lena; Reuther, Christina; Herden, Christiane; Roth, Joachim; Plesnila, Nikolaus; Culmsee, Carsten

2018-01-19

The tumor-suppressor cylindromatosis (CYLD) is a deubiquitinating enzyme and key regulator of cell proliferation and inflammation. A genome-wide siRNA screen linked CYLD to receptor interacting protein-1 (RIP1) kinase-mediated necroptosis; however, the exact mechanisms of CYLD-mediated cell death remain unknown. Therefore, we investigated the precise role of CYLD in models of neuronal cell death in vitro and evaluated whether CYLD deletion affects brain injury in vivo. In vitro, downregulation of CYLD increased RIP1 ubiquitination, prevented RIP1/RIP3 complex formation, and protected neuronal cells from oxidative death. Similar protective effects were achieved by siRNA silencing of RIP1 or RIP3 or by pharmacological inhibition of RIP1 with necrostatin-1. In vivo, CYLD knockout mice were protected from trauma-induced brain damage compared to wild-type littermate controls. These findings unravel the mechanisms of CYLD-mediated cell death signaling in damaged neurons in vitro and suggest a cell death-mediating role of CYLD in vivo.

BID links ferroptosis to mitochondrial cell death pathways.

PubMed

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

2017-08-01

Ferroptosis has been defined as an oxidative and iron-dependent pathway of regulated cell death that is distinct from caspase-dependent apoptosis and established pathways of death receptor-mediated regulated necrosis. While emerging evidence linked features of ferroptosis induced e.g. by erastin-mediated inhibition of the X c - system or inhibition of glutathione peroxidase 4 (Gpx4) to an increasing number of oxidative cell death paradigms in cancer cells, neurons or kidney cells, the biochemical pathways of oxidative cell death remained largely unclear. In particular, the role of mitochondrial damage in paradigms of ferroptosis needs further investigation. In the present study, we find that erastin-induced ferroptosis in neuronal cells was accompanied by BID transactivation to mitochondria, loss of mitochondrial membrane potential, enhanced mitochondrial fragmentation and reduced ATP levels. These hallmarks of mitochondrial demise are also established features of oxytosis, a paradigm of cell death induced by X c - inhibition by millimolar concentrations of glutamate. Bid knockout using CRISPR/Cas9 approaches preserved mitochondrial integrity and function, and mediated neuroprotective effects against both, ferroptosis and oxytosis. Furthermore, the BID-inhibitor BI-6c9 inhibited erastin-induced ferroptosis, and, in turn, the ferroptosis inhibitors ferrostatin-1 and liproxstatin-1 prevented mitochondrial dysfunction and cell death in the paradigm of oxytosis. These findings show that mitochondrial transactivation of BID links ferroptosis to mitochondrial damage as the final execution step in this paradigm of oxidative cell death. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Gingerol sensitizes TRAIL-induced apoptotic cell death of glioblastoma cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Dae-Hee, E-mail: leedneo@gmail.com; Kim, Dong-Wook; Jung, Chang-Hwa

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 ginger can induce TRAIL-mediated apoptosis of glioblastoma. Gingerol increased death receptor (DR) 5 levels in a p53-dependent manner. Furthermore, gingerol decreased the expression level of anti-apoptotic proteins (survivin, c-FLIP, Bcl-2, and XIAP) and increased pro-apoptotic protein, Bax and truncate Bid, by generating reactive oxygen species (ROS). We alsomore » found that the sensitizing effects of gingerol in TRAIL-induced cell death were blocked by scavenging ROS or overexpressing anti-apoptotic protein (Bcl-2). Therefore, we showed the functions of gingerol as a sensitizing agent to induce cell death of TRAIL-resistant glioblastoma cells. This study gives rise to the possibility of applying gingerol as an anti-tumor agent that can be used for the purpose of combination treatment with TRAIL in TRAIL-resistant glioblastoma tumor therapy. - Highlights: • Most GBM cells have been reported to be resistant to TRAIL-induced apoptosis. • Gingerol enhances the expression level of anti-apoptotic proteins by ROS. • Gingerol enhances TRAIL-induced apoptosis through actions on the ROS–Bcl2 pathway.« less

The novel piperazine-containing compound LQFM018: Necroptosis cell death mechanisms, dopamine D4 receptor binding and toxicological assessment.

PubMed

Costa, Fabiana Bettanin; Cortez, Alane P; de Ávila, Renato Ivan; de Carvalho, Flávio S; Andrade, Wanessa M; da Cruz, Andrezza F; Reis, Karinna B; Menegatti, Ricardo; Lião, Luciano M; Romeiro, Luiz Antônio S; Noël, François; Fraga, Carlos Alberto M; Barreiro, Eliezer J; Sanz, Germán; Rodrigues, Marcella F; Vaz, Boniek G; Valadares, Marize Campos

2018-06-01

Piperazine is a promising scaffold for drug development due to its broad spectrum of biological activities. Based on this, the new piperazine-containing compound LQFM018 (2) [ethyl 4-((1-(4-chlorophenyl)-1H-pyrazol-4-yl)methyl)piperazine-1-carboxylate] was synthetized and some biological activities investigated. In this work, we described its ability to bind aminergic receptors, antiproliferative effects as well as the LQFM018 (2)-triggered cell death mechanisms, in K562 leukemic cells, by flow cytometric analyses. Furthermore, acute oral systemic toxicity and potential myelotoxicity assessments of LQFM018 (2) were carried out. LQFM018 (2) was originally obtained by molecular simplification from LASSBio579 (1), an analogue compound of clozapine, with 33% of global yield. Binding profile assay to aminergic receptors showed that LQFM018 (2) has affinity for the dopamine D 4 receptor (K i  = 0.26 μM). Moreover, it showed cytotoxicity in K562 cells, in a concentration and time-dependent manner; IC 50 values obtained were 399, 242 and 119 μM for trypan blue assay and 427, 259 and 50 μM for MTT method at 24, 48 or 72 h, respectively. This compound (427 μM) also promoted increase in LDH release and cell cycle arrest in G2/M phase. Furthermore, it triggered necrotic morphologies in K562 cells associated with intense cell membrane rupture as confirmed by Annexin V/propidium iodide double-staining. LQFM018 (2) also triggered mitochondrial disturb through loss of ΔΨm associated with increase of ROS production. No significant accumulation of cytosolic cytochrome c was verified in treated cells. Furthermore, it was verified an increase of expression of TNF-R1 and mRNA levels of CYLD with no involviment in caspase-3 and -8 activation and NF-κB in K562 cells. LQFM018 (2) showed in vitro myelotoxicity potential, but it was orally well tolerated and classified as UN GHS category 5 (LD 50  > 2000-5000 mg/Kg). Thus, LQFM018 (2) seems to have a non

Death Receptor Expression on Blasts in AML Is Associated with Unfavorable Prognosis.

PubMed

Schmohl, Joerg Uwe; Nuebling, Tina; Wild, Julia; Jung, Johannes; Kroell, Tanja; Kanz, Lothar; Salih, Helmut R; Schmetzer, Helga

2015-07-01

Tumor necrosis factor (TNF) receptor family members play a key role in the regulation of biological functions such as differentiation, proliferation and apoptosis of various cell types. We studied co-expression profiles of death receptors from the TNF family [TNF-related apoptosis-inducing ligand receptor (TRAILR) 1 to 3, TNF receptor 1 (TNFR1) and FAS receptor (FAS)] on peripheral blood blasts from 46 patients with acute myeloid leukemia (AML) at first diagnosis by flow cytometry and correlated the obtained specific fluorescence indices (SFI) with morphological, cytogenetic and clinical parameters. We found that the expression of TRAILR2 and R3 was significantly increased in unfavorable risk groups, according to the National Comprehensive Cancer Network. Additionally, cut-off analyses for TRAILR2 and TNFR1 showed significantly shorter overall survival, earlier disease onset, higher proportions of cases with unfavorable prognosis and higher probability of relapse when SFIs were above the established cut-off. We demonstrate that high co-expression of death receptors on blasts is an independent predictor of poor prognosis in AML. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Interferon-induced TRAIL-independent cell death in DNase II-/- embryos.

PubMed

Kitahara, Yusuke; Kawane, Kohki; Nagata, Shigekazu

2010-09-01

The chromosomal DNA of apoptotic cells and the nuclear DNA expelled from erythroid precursors is cleaved by DNase II in lysosomes after the cells or nuclei are engulfed by macrophages. DNase II(-/-) embryos suffer from lethal anemia due to IFN-beta produced in the macrophages carrying undigested DNA. Here, we show that Type I IFN induced a caspase-dependent cell death in human epithelial cells that were transformed to express a high level of IFN type I receptor. During this death process, a set of genes was strongly activated, one of which encoded TRAIL, a death ligand. A high level of TRAIL mRNA was also found in the fetal liver of the lethally anemic DNase II(-/-) embryos, and a lack of IFN type I receptor in the DNase II(-/-) IFN-IR(-/-) embryos blocked the expression of TRAIL mRNA. However, a null mutation in TRAIL did not rescue the lethal anemia of the DNase II(-/-) embryos, indicating that TRAIL is dispensable for inducing the apoptosis of erythroid cells in DNase II(-/-) embryos, and therefore, that there is a TRAIL-independent mechanism for the IFN-induced apoptosis.

Toll-like Receptor 3 (TLR3) Induces Apoptosis via Death Receptors and Mitochondria by Up-regulating the Transactivating p63 Isoform α (TAP63α)*

PubMed Central

Sun, Ruili; Zhang, Yu; Lv, Qingshan; Liu, Bei; Jin, Miao; Zhang, Weijia; He, Qing; Deng, Minjie; Liu, Xueting; Li, Guancheng; Li, Yuehui; Zhou, Guohua; Xie, Pingli; Xie, Xiumei; Hu, Jinyue; Duan, Zhaojun

2011-01-01

Toll-like receptor 3 (TLR3), a member of the pathogen recognition receptors, is widely expressed in various cells and has been shown to activate immune signaling pathways by recognizing viral double-stranded RNA. Recently, it was reported that the activation of TLR3 induced apoptosis in some cells, but the detailed molecular mechanism is not fully understood. In this study, we found that in endothelial cells polyinosinic-polycytidylic acid (poly(I-C)) induced dose- and time-dependent cell apoptosis, which was elicited by TLR3 activation, as TLR3 neutralization and down-regulation repressed the apoptosis. Poly(I-C) induced the activation of both caspases 8 and 9, indicating that TLR3 triggered the signaling of both the extrinsic and intrinsic apoptotic pathways. Poly(I-C) up-regulated tumor necrosis factor-related apoptosis-inducing ligand and its receptors, death receptors 4/5, resulting in initiating the extrinsic pathway. Furthermore, poly(I-C) down-regulated anti-apoptotic protein, B cell lymphoma 2 (Bcl-2), and up-regulated Noxa, a key Bcl-2 homology 3-only antagonist of Bcl-2, leading to the priming of the intrinsic pathway. A p53-related protein, the transactivating p63 isoform α (TAp63α), was induced by TLR3 activation and contributed to the activation of both the intrinsic and extrinsic apoptotic pathways. Both the cells deficient in p63 gene expression by RNA interference and cells that overexpressed the N-terminally truncated p63 isoform α (ΔNp63α), a dominant-negative variant of TAp63α, by gene transfection, survived TLR3 activation. Taken together, TAp63α is a crucial regulator downstream of TLR3 to induce cell death via death receptors and mitochondria. PMID:21367858

Bid Participates in Genotoxic Drug-Induced Apoptosis of HeLa Cells and Is Essential for Death Receptor Ligands' Apoptotic and Synergistic Effects

PubMed Central

Concannon, Caoimhin G.; Rehm, Markus; Kögel, Donat; Prehn, Jochen H. M.

2008-01-01

Background The BH3-only protein Bid is an important component of death receptor-mediated caspase activation. Bid is cleaved by caspase-8 or -10 into t-Bid, which translocates to mitochondria and triggers the release of caspase-activating factors. Bid has also been reported to be cleaved by other proteases. Methodology/Principal Findings To test the hypothesis that Bid is a central mediator of stress-induced apoptosis, we investigated the effects of a small molecule Bid inhibitor on stress-induced apoptosis, and generated HeLa cells deficient for Bid. Stable knockdown of bid lead to a pronounced resistance to Fas/CD95- and TRAIL-induced caspase activation and apoptosis, and significantly increased clonogenic survival. While Bid-deficient cells were equally sensitive to ER stress-induced apoptosis, they showed moderate, but significantly reduced levels of apoptosis, as well as increased clonogenic survival in response to the genotoxic drugs Etoposide, Oxaliplatin, and Doxorubicin. Similar effects were observed using the Bid inhibitor BI6C9. Interestingly, Bid-deficient cells were dramatically protected from apoptosis when subtoxic concentrations of ER stressors, Etoposide or Oxaliplatin were combined with subtoxic TRAIL concentrations. Conclusions/Significance Our data demonstrate that Bid is central for death receptor-induced cell death and participates in anti-cancer drug-induced apoptosis in human cervical cancer HeLa cells. They also show that the synergistic effects of TRAIL in combination with either ER stressors or genotoxic anti-cancer drugs are nearly exclusively mediated via an increased activation of Bid-induced apoptosis signalling. PMID:18665234

Pannexin1 channels act downstream of P2X7 receptors in ATP-induced murine T-cell death

PubMed Central

Shoji, Kenji F; Sáez, Pablo J; Harcha, Paloma A; Aguila, Hector L; Sáez, Juan C

2014-01-01

Death of murine T cells induced by extracellular ATP is mainly triggered by activation of purinergic P2X7 receptors (P2X7Rs). However, a link between P2X7Rs and pannexin1 (Panx1) channels, which are non-selective, has been recently demonstrated in other cell types. In this work, we characterized the expression and cellular distribution of pannexin family members (Panxs 1, 2 and 3) in isolated T cells. Panx1 was the main pannexin family member clearly detected in both helper (CD4+) and cytotoxic (CD8+) T cells, whereas low levels of Panx2 were found in both T-cell subsets. Using pharmacological and genetic approaches, Panx1 channels were found to mediate most ATP-induced ethidium uptake since this was drastically reduced by Panx1 channel blockers (10Panx1, Probenecid and low carbenoxolone concentration) and absent in T cells derived from Panx1−/− mice. Moreover, electrophysiological measurements in wild-type CD4+ cells treated with ATP unitary current events and pharmacological sensitivity compatible with Panx1 channels were found. In addition, ATP release from T cells treated with 4Br-A23187, a calcium ionophore, was completely blocked with inhibitors of both connexin hemichannels and Panx1 channels. Panx1 channel blockers drastically reduced the ATP-induced T-cell mortality, indicating that Panx1 channels mediate the ATP-induced T-cell death. However, mortality was not reduced in T cells of Panx1−/− mice, in which levels of P2X7Rs and ATP-induced intracellular free Ca2+ responses were enhanced suggesting that P2X7Rs take over Panx1 channels lose-function in mediating the onset of cell death induced by extracellular ATP. PMID:24590064

Control of non-apoptotic nurse cell death by engulfment genes in Drosophila.

PubMed

Timmons, Allison K; Mondragon, Albert A; Meehan, Tracy L; McCall, Kimberly

2017-04-03

Programmed cell death occurs as a normal part of oocyte development in Drosophila. For each egg that is formed, 15 germline-derived nurse cells transfer their cytoplasmic contents into the oocyte and die. Disruption of apoptosis or autophagy only partially inhibits the death of the nurse cells, indicating that other mechanisms significantly contribute to nurse cell death. Recently, we demonstrated that the surrounding stretch follicle cells non-autonomously promote nurse cell death during late oogenesis and that phagocytosis genes including draper, ced-12, and the JNK pathway are crucial for this process. When phagocytosis genes are inhibited in the follicle cells, events specifically associated with death of the nurse cells are impaired. Death of the nurse cells is not completely blocked in draper mutants, suggesting that other engulfment receptors are involved. Indeed, we found that the integrin subunit, αPS3, is enriched on stretch follicle cells during late oogenesis and is required for elimination of the nurse cells. Moreover, double mutant analysis revealed that integrins act in parallel to draper. Death of nurse cells in the Drosophila ovary is a unique example of programmed cell death that is both non-apoptotic and non-cell autonomously controlled.

Regulation of cell death and cell survival gene expression during ovarian follicular development and atresia.

PubMed

Jiang, Jin-Yi; Cheung, Carmen K M; Wang, Yifang; Tsang, Benjamin K

2003-01-01

Mammalian ovarian follicular development and atresia is closely regulated by the cross talk of cell death and cell survival signals, which include endocrine hormones (gonadotropins) and intra-ovarian regulators (gonadal steroids, cytokines and growth factors). The fate of the follicle is dependent on a delicate balance in the expression and actions of factors promoting follicular cell proliferation, growth and differentiation and of those inducing programmed cell death (apoptosis). As an important endocrine hormone, FSH binds to its granulosa cell receptors and promotes ovarian follicle survival and growth not only by stimulating proliferation and estradiol secretion of these cells, but also inhibiting the apoptosis by up-regulating the expression of intracellular anti-apoptotic proteins, such as XIAP and FLIP. In addition, intra-ovarian regulators, such as TGF-alpha and TNF-alpha, also play an important role in the control of follicular development and atresia. In response to FSH, Estradiol-17 beta synthesized from the granulosa cells stimulates thecal expression of TGF-alpha, which in turn increases granulosa cell XIAP expression and proliferation. The death receptor and ligand, Fas and Fas ligand, are expressed in granulosa cells following gonadotropin withdrawal, culminating in caspase-mediated apoptosis and follicular atresia. In contrast, TNF-alpha has both survival and pro-apoptotic function in the follicle, depending on the receptor subtype activated, but has been shown to promote granulosa cell survival by increasing XIAP and FLIP expression via the IkappaB-NFkappaB pathway. The pro-apoptotic action of TNF-alpha is mediated through the activation of caspases, via its receptor- (i.e. Caspases-8 and -3) and mitochrondria- (i.e. Caspase-9 and -3) death pathways. In the present manuscript, we have reviewed the actions and interactions of gonadotropins and intra-ovarian regulators in the control of granulosa cell fate and ultimately follicular destiny. We have

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).

Lack of the programmed death-1 receptor renders host susceptible to enteric microbial infection through impairing the production of the mucosal natural killer cell effector molecules.

PubMed

Solaymani-Mohammadi, Shahram; Lakhdari, Omar; Minev, Ivelina; Shenouda, Steve; Frey, Blake F; Billeskov, Rolf; Singer, Steven M; Berzofsky, Jay A; Eckmann, Lars; Kagnoff, Martin F

2016-03-01

The programmed death-1 receptor is expressed on a wide range of immune effector cells, including T cells, natural killer T cells, dendritic cells, macrophages, and natural killer cells. In malignancies and chronic viral infections, increased expression of programmed death-1 by T cells is generally associated with a poor prognosis. However, its role in early host microbial defense at the intestinal mucosa is not well understood. We report that programmed death-1 expression is increased on conventional natural killer cells but not on CD4(+), CD8(+) or natural killer T cells, or CD11b(+) or CD11c(+) macrophages or dendritic cells after infection with the mouse pathogen Citrobacter rodentium. Mice genetically deficient in programmed death-1 or treated with anti-programmed death-1 antibody were more susceptible to acute enteric and systemic infection with Citrobacter rodentium. Wild-type but not programmed death-1-deficient mice infected with Citrobacter rodentium showed significantly increased expression of the conventional mucosal NK cell effector molecules granzyme B and perforin. In contrast, natural killer cells from programmed death-1-deficient mice had impaired expression of those mediators. Consistent with programmed death-1 being important for intracellular expression of natural killer cell effector molecules, mice depleted of natural killer cells and perforin-deficient mice manifested increased susceptibility to acute enteric infection with Citrobacter rodentium. Our findings suggest that increased programmed death-1 signaling pathway expression by conventional natural killer cells promotes host protection at the intestinal mucosa during acute infection with a bacterial gut pathogen by enhancing the expression and production of important effectors of natural killer cell function. © Society for Leukocyte Biology.

NADE, a p75NTR-associated cell death executor, is involved in signal transduction mediated by the common neurotrophin receptor p75NTR.

PubMed

Mukai, J; Hachiya, T; Shoji-Hoshino, S; Kimura, M T; Nadano, D; Suvanto, P; Hanaoka, T; Li, Y; Irie, S; Greene, L A; Sato, T A

2000-06-09

The low affinity neurotrophin receptor p75NTR can mediate cell survival as well as cell death of neural cells by NGF and other neurotrophins. To elucidate p75NTR-mediated signal transduction, we screened p75NTR-associated proteins by a yeast two-hybrid system. We identified one positive clone and named NADE (p75NTR-associated cell death executor). Mouse NADE has marked homology to the human HGR74 protein. NADE specifically binds to the cell-death domain of p75NTR. Co-expression of NADE and p75NTR induced caspase-2 and caspase-3 activities and the fragmentation of nuclear DNA in 293T cells. However, in the absence of p75NTR, NADE failed to induce apoptosis, suggesting that NADE expression is necessary but insufficient for p75NTR-mediated apoptosis. Furthermore, p75NTR/NADE-induced cell death was dependent on NGF but not BDNF, NT-3, or NT-4/5, and the recruitment of NADE to p75NTR (intracellular domain) was dose-dependent. We obtained similar results from PC12 cells, nnr5 cells, and oligodendrocytes. Taken together, NADE is the first signaling adaptor molecule identified in the involvement of p75NTR-mediated apoptosis induced by NGF, and it may play an important role in the pathogenesis of neurogenetic diseases.

TRAIL-death receptor endocytosis and apoptosis are selectively regulated by dynamin-1 activation.

PubMed

Reis, Carlos R; Chen, Ping-Hung; Bendris, Nawal; Schmid, Sandra L

2017-01-17

Clathrin-mediated endocytosis (CME) constitutes the major pathway for uptake of signaling receptors into eukaryotic cells. As such, CME regulates signaling from cell-surface receptors, but whether and how specific signaling receptors reciprocally regulate the CME machinery remains an open question. Although best studied for its role in membrane fission, the GTPase dynamin also regulates early stages of CME. We recently reported that dynamin-1 (Dyn1), previously assumed to be neuron-specific, can be selectively activated in cancer cells to alter endocytic trafficking. Here we report that dynamin isoforms differentially regulate the endocytosis and apoptotic signaling downstream of TNF-related apoptosis-inducing ligand-death receptor (TRAIL-DR) complexes in several cancer cells. Whereas the CME of constitutively internalized transferrin receptors is mainly dependent on the ubiquitously expressed Dyn2, TRAIL-induced DR endocytosis is selectively regulated by activation of Dyn1. We show that TRAIL stimulation activates ryanodine receptor-mediated calcium release from endoplasmic reticulum stores, leading to calcineurin-mediated dephosphorylation and activation of Dyn1, TRAIL-DR endocytosis, and increased resistance to TRAIL-induced apoptosis. TRAIL-DR-mediated ryanodine receptor activation and endocytosis is dependent on early caspase-8 activation. These findings delineate specific mechanisms for the reciprocal crosstalk between signaling and the regulation of CME, leading to autoregulation of endocytosis and signaling downstream of surface receptors.

TRAIL-death receptor endocytosis and apoptosis are selectively regulated by dynamin-1 activation

PubMed Central

Reis, Carlos R.; Chen, Ping-Hung; Bendris, Nawal; Schmid, Sandra L.

2017-01-01

Clathrin-mediated endocytosis (CME) constitutes the major pathway for uptake of signaling receptors into eukaryotic cells. As such, CME regulates signaling from cell-surface receptors, but whether and how specific signaling receptors reciprocally regulate the CME machinery remains an open question. Although best studied for its role in membrane fission, the GTPase dynamin also regulates early stages of CME. We recently reported that dynamin-1 (Dyn1), previously assumed to be neuron-specific, can be selectively activated in cancer cells to alter endocytic trafficking. Here we report that dynamin isoforms differentially regulate the endocytosis and apoptotic signaling downstream of TNF-related apoptosis-inducing ligand–death receptor (TRAIL–DR) complexes in several cancer cells. Whereas the CME of constitutively internalized transferrin receptors is mainly dependent on the ubiquitously expressed Dyn2, TRAIL-induced DR endocytosis is selectively regulated by activation of Dyn1. We show that TRAIL stimulation activates ryanodine receptor-mediated calcium release from endoplasmic reticulum stores, leading to calcineurin-mediated dephosphorylation and activation of Dyn1, TRAIL–DR endocytosis, and increased resistance to TRAIL-induced apoptosis. TRAIL–DR-mediated ryanodine receptor activation and endocytosis is dependent on early caspase-8 activation. These findings delineate specific mechanisms for the reciprocal crosstalk between signaling and the regulation of CME, leading to autoregulation of endocytosis and signaling downstream of surface receptors. PMID:28049841

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

PubMed

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

2015-10-01

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

How Kidney Cell Death Induces Renal Necroinflammation.

PubMed

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

2016-05-01

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

Akt-phosphorylated Mitogen-activated Kinase-activating Death Domain Protein (MADD) Inhibits TRAIL-induced Apoptosis by Blocking Fas-associated Death Domain (FADD) Association with Death Receptor 4*

PubMed Central

Li, Peifeng; Jayarama, Shankar; Ganesh, Lakshmy; Mordi, David; Carr, Ryan; Kanteti, Prasad; Hay, Nissim; Prabhakar, Bellur S.

2010-01-01

MADD plays an essential role in cancer cell survival. Abrogation of endogenous MADD expression results in significant spontaneous apoptosis and enhanced susceptibility to tumor necrosis factor α-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. However, the regulation of MADD function is largely unknown. Here, we demonstrate that endogenous MADD is phosphorylated at three highly conserved sites by Akt, and only the phosphorylated MADD can directly interact with the TRAIL receptor DR4 thereby preventing Fas-associated death domain recruitment. However, in cells susceptible to TRAIL treatment, TRAIL induces a reduction in MADD phosphorylation levels resulting in MADD dissociation from, and Fas-associated death domain association with DR4, which allows death-inducing signaling complex (DISC) formation leading to apoptosis. Thus, the pro-survival function of MADD is dependent upon its phosphorylation by Akt. Because Akt is active in most cancer cells and phosphorylated MADD confers resistance to TRAIL-induced apoptosis, co-targeting Akt-MADD axis is likely to increase efficacy of TRAIL-based therapies. PMID:20484047

Lysosome-mediated Cell Death and Autophagy-Dependent Multidrug Resistance in Breast Cancer

DTIC Science & Technology

2008-10-01

gene links mitochondria and cell death, the data suggests that Bcl2 may be involved in autophagic cell death and AD-MDR. GeneGo analysis also...GSK3 beta GSK3 beta E2A p53 p21 p21 E2F1 PPAR -gamma JNK1(MA PK8) JNK1(M APK8) ESR1 (nuclear) RARalpha Androgen receptor Androge n receptor p53...RelA (p65 NF-kB subunit) Erk (MAPK1/3 ) Erk (MAPK1/ 3) PPAR - gamma SOX9 Bcl-2 Bcl-2 RARalpha SP1 EGFR EGFR RelA (p65 NF- kB subunit) RARalpha RelA

UV-Induced Cell Death in Plants

PubMed Central

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

2013-01-01

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). PMID:23344059

Loss of diphthamide pre-activates NF-κB and death receptor pathways and renders MCF7 cells hypersensitive to tumor necrosis factor.

PubMed

Stahl, Sebastian; da Silva Mateus Seidl, Ana Rita; Ducret, Axel; Kux van Geijtenbeek, Sabine; Michel, Sven; Racek, Tomas; Birzele, Fabian; Haas, Alexander K; Rueger, Ruediger; Gerg, Michael; Niederfellner, Gerhard; Pastan, Ira; Brinkmann, Ulrich

2015-08-25

The diphthamide on human eukaryotic translation elongation factor 2 (eEF2) is the target of ADP ribosylating diphtheria toxin (DT) and Pseudomonas exotoxin A (PE). This modification is synthesized by seven dipthamide biosynthesis proteins (DPH1-DPH7) and is conserved among eukaryotes and archaea. We generated MCF7 breast cancer cell line-derived DPH gene knockout (ko) cells to assess the impact of complete or partial inactivation on diphthamide synthesis and toxin sensitivity, and to address the biological consequence of diphthamide deficiency. Cells with heterozygous gene inactivation still contained predominantly diphthamide-modified eEF2 and were as sensitive to PE and DT as parent cells. Thus, DPH gene copy number reduction does not affect overall diphthamide synthesis and toxin sensitivity. Complete inactivation of DPH1, DPH2, DPH4, and DPH5 generated viable cells without diphthamide. DPH1ko, DPH2ko, and DPH4ko harbored unmodified eEF2 and DPH5ko ACP- (diphthine-precursor) modified eEF2. Loss of diphthamide prevented ADP ribosylation of eEF2, rendered cells resistant to PE and DT, but does not affect sensitivity toward other protein synthesis inhibitors, such as saporin or cycloheximide. Surprisingly, cells without diphthamide (independent of which the DPH gene compromised) were presensitized toward nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB) and death-receptor pathways without crossing lethal thresholds. In consequence, loss of diphthamide rendered cells hypersensitive toward TNF-mediated apoptosis. This finding suggests a role of diphthamide in modulating NF-κB, death receptor, or apoptosis pathways.

Dictyostelium cell death

PubMed Central

Levraud, Jean-Pierre; Adam, Myriam; Luciani, Marie-Françoise; de Chastellier, Chantal; Blanton, Richard L.; Golstein, Pierre

2003-01-01

Cell death in the stalk of Dictyostelium discoideum, a prototypic vacuolar cell death, can be studied in vitro using cells differentiating as a monolayer. To identify early events, we examined potentially dying cells at a time when the classical signs of Dictyostelium cell death, such as heavy vacuolization and membrane lesions, were not yet apparent. We observed that most cells proceeded through a stereotyped series of differentiation stages, including the emergence of “paddle” cells showing high motility and strikingly marked subcellular compartmentalization with actin segregation. Paddle cell emergence and subsequent demise with paddle-to-round cell transition may be critical to the cell death process, as they were contemporary with irreversibility assessed through time-lapse videos and clonogenicity tests. Paddle cell demise was not related to formation of the cellulose shell because cells where the cellulose-synthase gene had been inactivated underwent death indistinguishable from that of parental cells. A major subcellular alteration at the paddle-to-round cell transition was the disappearance of F-actin. The Dictyostelium vacuolar cell death pathway thus does not require cellulose synthesis and includes early actin rearrangements (F-actin segregation, then depolymerization), contemporary with irreversibility, corresponding to the emergence and demise of highly polarized paddle cells. PMID:12654899

Receptor tyrosine kinases play a significant role in human oligodendrocyte inflammation and cell death associated with the Lyme disease bacterium Borrelia burgdorferi.

PubMed

Parthasarathy, Geetha; Philipp, Mario T

2017-05-30

In previous studies, human oligodendrocytes were demonstrated to undergo apoptosis in the presence of Borrelia burgdorferi under an inflammatory milieu. Subsequently, we determined that the MEK/ERK pathway played a significant role in triggering downstream inflammation as well as apoptosis. However, the identity of receptors triggered by exposure to B. burgdorferi and initiating signaling events was unknown. In this study, we explored the role of several TLR and EGFR/FGFR/PDGFR tyrosine kinase pathways in inducing inflammation in the presence of B. burgdorferi, using siRNA and/or inhibitors, in MO3.13 human oligodendrocytes. Cell death and apoptosis assays were also carried out in the presence or absence of specific receptor inhibitors along with the bacteria to determine the role of these receptors in apoptosis induction. The expression pattern of specific receptors with or without B. burgdorferi was also determined. TLRs 2 and 5 had a minimal role in inducing inflammation, particularly IL-6 production. Rather, their effect was mostly inhibitory, with TLR2 downregulation significantly upregulating CXCL8, and CXCL (1,2,3) levels, and TLR5 likely having a similar role in CXCL8, CXCL(1,2,3), and CCL5 levels. TLR4 contributed mostly towards CCL5 production. On the other hand, inhibition of all three EGF/FGF/PDGF receptors significantly downregulated all five of the inflammatory mediators tested even in the presence of B. burgdorferi. Their inhibition also downregulated overall cell death and apoptosis levels. The expression pattern of these receptors, as assessed by immunohistochemistry indicated that the PDGFRβ receptor was the most predominantly expressed receptor, followed by FGFR, although no significant differences were discernible between presence and absence of bacteria. Interestingly, inhibition of individual EGFR, FGFR, or PDGFR receptors did not indicate an individual role for any of these receptors in the overall downregulation of pathogenesis. Contrarily

Necroptosis: an alternative cell death program defending against cancer

PubMed Central

Chen, Dongshi; Yu, Jian; Zhang, Lin

2016-01-01

One of the hallmarks of cancer is resistance to programmed cell death, which maintains the survival of cells en route to oncogenic transformation and underlies therapeutic resistance. Recent studies demonstrate that programmed cell death is not confined to caspase-dependent apoptosis, but includes necroptosis, a form of necrotic death governed by Receptor-Interacting Protein 1 (RIP1), RIP3, and Mixed Lineage Kinase Domain-Like (MLKL). Necroptosis serves as a critical cell-killing mechanism in response to severe stress and blocked apoptosis, and can be induced by inflammatory cytokines or chemotherapeutic drugs. Genetic or epigenetic alterations of necroptosis regulators such as RIP3 and cylindromatosis (CYLD), are frequently found in human tumors. Unlike apoptosis, necroptosis elicits a more robust immune response that may function as a defensive mechanism by eliminating tumor-causing mutations and viruses. Furthermore, several classes of anticancer agents currently under clinical development, such as SMAC and BH3 mimetics, can promote necroptosis in addition to apoptosis. A more complete understanding of the interplay among necroptosis, apoptosis, and other cell death modalities is critical for developing new therapeutic strategies to enhance killing of tumor cells. PMID:26968619

Necroptosis: an alternative cell death program defending against cancer.

PubMed

Chen, Dongshi; Yu, Jian; Zhang, Lin

2016-04-01

One of the hallmarks of cancer is resistance to programmed cell death, which maintains the survival of cells en route to oncogenic transformation and underlies therapeutic resistance. Recent studies demonstrate that programmed cell death is not confined to caspase-dependent apoptosis, but includes necroptosis, a form of necrotic death governed by Receptor-Interacting Protein 1 (RIP1), RIP3, and Mixed Lineage Kinase Domain-Like (MLKL) protein. Necroptosis serves as a critical cell-killing mechanism in response to severe stress and blocked apoptosis, and can be induced by inflammatory cytokines or chemotherapeutic drugs. Genetic or epigenetic alterations of necroptosis regulators such as RIP3 and cylindromatosis (CYLD), are frequently found in human tumors. Unlike apoptosis, necroptosis elicits a more robust immune response that may function as a defensive mechanism by eliminating tumor-causing mutations and viruses. Furthermore, several classes of anticancer agents currently under clinical development, such as SMAC and BH3 mimetics, can promote necroptosis in addition to apoptosis. A more complete understanding of the interplay among necroptosis, apoptosis, and other cell death modalities is critical for developing new therapeutic strategies to enhance killing of tumor cells. Copyright © 2016 Elsevier B.V. All rights reserved.

Nuclear receptors in pancreatic tumor cells.

PubMed

Damaskos, Christos; Garmpis, Nikolaos; Karatzas, Theodore; Kostakis, Ioannis D; Nikolidakis, Lampros; Kostakis, Alkiviadis; Kouraklis, Gregory

2014-12-01

This review focuses on nuclear receptors expressed in pancreatic cancer. An extensive search of articles published up to March 2013 was conducted using the MEDLINE database. The key words used were "pancreatic cancer", "molecular receptors" and "growth factors". A total of 112 articles referred to pancreatic cancer, molecular receptors and/or growth factors were included. Receptors of growth factors, such as the epithelial growth factor receptor, insulin-like growth factor-1 receptor, vascular endothelial growth factor receptor and others, such as integrin α5β1, somatostatin receptors, the death receptor 5, claudin, notch receptors, mesothelin receptors, follicle-stimulating hormone receptors, the MUC1 receptor, the adrenomedullin receptor, the farnesoid X receptor, the transferrin receptor, sigma-2 receptors, the chemokine receptor CXCR4, the urokinase plasminogen activator receptor, the ephrine A2 receptor, the GRIA3 receptor, the RON receptor and the angiotensin II receptor AT-1 are expressed in pancreatic tumor cells. These molecules are implicated in tumor growth, apoptosis, angiogenesis, metastasis etc. After identifying the molecular receptors associated with the pancreatic cancer, many more target molecules playing important roles in tumor pathophysiology and senescence-associated signal transduction in cancer cells will be identified. This may have a significant influence on diagnosis, therapy and prognosis of pancreatic cancer. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Induction of tissue transglutaminase by dexamethasone: its correlation to receptor number and transglutaminase-mediated cell death in a series of malignant hamster fibrosarcomas.

PubMed Central

Johnson, T S; Scholfield, C I; Parry, J; Griffin, M

1998-01-01

Treatment of the hamster fibrosarcoma cell lines (Met B, D and E) and BHK-21 hamster fibroblast cells with the glucocorticoid dexamethasone led to a powerful dose-dependent mRNA-synthesis-dependent increase in transglutaminase activity, which can be correlated with dexamethasone-responsive receptor numbers in each cell line. Increasing the number of dexamethasone-responsive receptors by transfection of cells with the HG1 glucocorticoid receptor protein caused an increase in transglutaminase activity that was proportional to the level of transfected receptor. In all experiments the levels of the tissue transglutaminase-mediated detergent-insoluble bodies was found to be comparable with increases in transglutaminase activity. Despite an increase in detergent-insoluble body formation, an increase in apoptosis as measured by DNA fragmentation was not found. Incubation of cells with the non-toxic competitive transglutaminase substrate fluorescein cadaverine led to the incorporation of this fluorescent amine into cellular proteins when cells were damaged after exposure to trypsin during cell passage. These cross-linked proteins containing fluorescein cadaverine were shown to be present in the detergent-insoluble bodies, indicating that the origin of these bodies is via activation of tissue transglutaminase after cell damage by trypsinization rather than apoptosis per se, since Met B cells expressing the bcl-2 cDNA were not protected from detergent-insoluble body formation. We describe a novel mechanism of cell death related to tissue transglutaminase expression and cell damage. PMID:9512467

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

Gene Expression Analysis Implicates a Death Receptor Pathway in Schizophrenia Pathology

PubMed Central

Catts, Vibeke Sørensen; Shannon Weickert, Cynthia

2012-01-01

An increase in apoptotic events may underlie neuropathology in schizophrenia. By data-mining approaches, we identified significant expression changes in death receptor signaling pathways in the dorsolateral prefrontal cortex (DLPFC) of patients with schizophrenia, particularly implicating the Tumor Necrosis Factor Superfamily member 6 (FAS) receptor and the Tumor Necrosis Factor [ligand] Superfamily member 13 (TNFSF13) in schizophrenia. We sought to confirm and replicate in an independent tissue collection the noted mRNA changes with quantitative real-time RT-PCR. To test for regional and diagnostic specificity, tissue from orbital frontal cortex (OFC) was examined and a bipolar disorder group included. In schizophrenia, we confirmed and replicated significantly increased expression of TNFSF13 mRNA in the DLPFC. Also, a significantly larger proportion of subjects in the schizophrenia group had elevated FAS receptor expression in the DLPFC relative to unaffected controls. These changes were not observed in the bipolar disorder group. In the OFC, there were no significant differences in TNFSF13 or FAS receptor mRNA expression. Decreases in BH3 interacting domain death agonist (BID) mRNA transcript levels were found in the schizophrenia and bipolar disorder groups affecting both the DLPFC and the OFC. We tested if TNFSF13 mRNA expression correlated with neuronal mRNAs in the DLPFC, and found significant negative correlations with interneuron markers, parvalbumin and somatostatin, and a positive correlation with PPP1R9B (spinophilin), but not DLG4 (PSD-95). The expression of TNFSF13 mRNA in DLPFC correlated negatively with tissue pH, but decreasing pH in cultured cells did not cause increased TNFSF13 mRNA nor did exogenous TNFSF13 decrease pH. We concluded that increased TNFSF13 expression may be one of several cell-death cytokine abnormalities that contribute to the observed brain pathology in schizophrenia, and while increased TNFSF13 may be associated with lower

Sensitization of vascular smooth muscle cell to TNF-{alpha}-mediated death in the presence of palmitate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rho, Mun-Chual; Ah Lee, Kyeong; Mi Kim, Sun

2007-05-01

Saturated free fatty acids (FFAs), including palmitate, can activate the intrinsic death pathway in cells. However, the relationship between FFAs and receptor-mediated death pathway is still unknown. In this study, we have investigated whether FFAs are able to trigger receptor-mediated death. In addition, to clarify the mechanisms responsible for the activation, we examined the biochemical changes in dying vascular smooth muscle cell (VSMC) and the effects of various molecules to the receptor-mediated VSMC death. Tumor necrosis factor (TNF)-{alpha}-mediated VSMC death occurred in the presence of sub-cytotoxic concentration of palmitate as determined by assessing viability and DNA degradation, while the cytokinemore » did not influence VSMC viability in the presence of oleate. The VSMC death was inhibited by the gene transfer of a dominant-negative Fas-associated death domain-containing protein and the baculovirus p35, but not by the bcl-xL or the c-Jun N-terminal kinase (JNK) binding domain of JNK-interacting protein-1, in tests utilizing recombinant adenoviruses. The VSMC death was also inhibited by a neutralizing anti-TNF receptor 1 antibody, the caspase inhibitor z-VAD, and the cathepsin B inhibitor CA074, a finding indicative of the role of both caspases and cathepsin B in this process. Consistent with this finding, caspase-3 activation and an increase in cytosolic cathepsin B activity were detected in the dying VSMC. Palmitate inhibited an increase of TNF-{alpha}-mediated nuclear factor kappa B (NF-{kappa}B) activity, the survival pathway activated by the cytokine, by hindering the translocation of the NF-{kappa}B subunit of p65 from the cytosol into the nucleus. The gene transfer of inhibitor of NF-{kappa}B predisposed VSMC to palmitate-induced cell death. To the best of our knowledge, this study is the first report to demonstrate the activation of TNF-{alpha}-mediated cell death in the presence of palmitate. The current study proposes that FFAs would take

Lead induces apoptosis in mouse TM3 Leydig cells through the Fas/FasL death receptor pathway.

PubMed

He, Xiuyuan; Wu, Jing; Yuan, Liyun; Lin, Feng; Yi, Jine; Li, Jing; Yuan, Hui; Shi, Jinling; Yuan, Tingting; Zhang, Shufang; Fan, Yongheng; Zhao, Zhihang

2017-12-01

The study was aimed to investigate the effect of Pb toxicity on mouse Leydig cells and its molecular mechanism. The TM3 cells were cultured in vitro and exposed to Pb at different concentrations for 24h. The effects of Pb on cell proliferation and apoptosis were analyzed with MTT and Annexin V-FITC/PI via flow cytometry, respectively. Expression levels of Fas, Fas-L and caspase-8 in TM3 cells were determined by western blot. As well as the inhibitory effect of the caspase-8 inhibitor Z-IETD-FMK on cell apoptosis. We found that Pb treatment significantly decreased the cellar viability (P<0.05), increased the apoptosis (P<0.01) and the Fas, FasL, and caspase-8 expression levels in Pb-treated cells as compared to the control cells (P<0.05 or P<0.01). Furthermore, the caspase-8 inhibitor effectively block the Pb-induced cell apoptosis. Taken together, our data suggest that Pb-induced TM3 cell toxic effect may involve in the Fas/FasL death receptor signaling pathway. Copyright © 2017. Published by Elsevier B.V.

Elevated extracellular [K+] inhibits death-receptor- and chemical-mediated apoptosis prior to caspase activation and cytochrome c release.

PubMed Central

Thompson, G J; Langlais, C; Cain, K; Conley, E C; Cohen, G M

2001-01-01

Efflux of intracellular K(+) and cell shrinkage are features of apoptosis in many experimental systems, and a regulatory role has been proposed for cytoplasmic [K(+)] in initiating apoptosis. We have investigated this in both death-receptor-mediated and chemical-induced apoptosis. Using Jurkat T cells pre-loaded with the K(+) ion surrogate (86)Rb(+), we have demonstrated an efflux of intracellular K(+) during apoptosis that was concomitant with, but did not precede, other apoptotic changes, including phosphatidylserine externalization, mitochondrial depolarization and cell shrinkage. To further clarify the role of K(+) ions in apoptosis, cytoprotection by elevated extracellular [K(+)] was studied. Induction of apoptosis by diverse death-receptor and chemical stimuli in two cell lines was inhibited prior to phosphatidylserine externalization, mitochondrial depolarization, cytochrome c release and caspase activation. Using a cell-free system, we have demonstrated a novel mechanism by which increasing [K(+)] inhibited caspase activation. In control dATP-activated lysates, Apaf-1 oligomerized to a biologically active caspase processing approximately 700 kDa complex and an inactive approximately 1.4 MDa complex. Increasing [K(+)] inhibited caspase activation by preventing formation of the approximately 700 kDa complex, but not of the inactive complex. Thus intracellular and extracellular [K(+)] markedly affect caspase activation and the initiation of apoptosis induced by both death-receptor ligation and chemical stress. PMID:11415444

Rip3 knockdown rescues photoreceptor cell death in blind pde6c zebrafish.

PubMed

Viringipurampeer, I A; Shan, X; Gregory-Evans, K; Zhang, J P; Mohammadi, Z; Gregory-Evans, C Y

2014-05-01

Achromatopsia is a progressive autosomal recessive retinal disease characterized by early loss of cone photoreceptors and later rod photoreceptor loss. In most cases, mutations have been identified in CNGA3, CNGB3, GNAT2, PDE6C or PDE6H genes. Owing to this genetic heterogeneity, mutation-independent therapeutic schemes aimed at preventing cone cell death are very attractive treatment strategies. In pde6c(w59) mutant zebrafish, cone photoreceptors expressed high levels of receptor-interacting protein kinase 1 (RIP1) and receptor-interacting protein kinase 3 (RIP3) kinases, key regulators of necroptotic cell death. In contrast, rod photoreceptor cells were alternatively immunopositive for caspase-3 indicating activation of caspase-dependent apoptosis in these cells. Morpholino gene knockdown of rip3 in pde6c(w59) embryos rescued the dying cone photoreceptors by inhibiting the formation of reactive oxygen species and by inhibiting second-order neuron remodelling in the inner retina. In rip3 morphant larvae, visual function was restored in the cones by upregulation of the rod phosphodiesterase genes (pde6a and pde6b), compensating for the lack of cone pde6c suggesting that cones are able to adapt to their local environment. Furthermore, we demonstrated through pharmacological inhibition of RIP1 and RIP3 activity that cone cell death was also delayed. Collectively, these results demonstrate that the underlying mechanism of cone cell death in the pde6c(w59) mutant retina is through necroptosis, whereas rod photoreceptor bystander death occurs through a caspase-dependent mechanism. This suggests that targeting the RIP kinase signalling pathway could be an effective therapeutic intervention in retinal degeneration patients. As bystander cell death is an important feature of many retinal diseases, combinatorial approaches targeting different cell death pathways may evolve as an important general principle in treatment.

TNFα sensitizes neuroblastoma cells to FasL-, cisplatin- and etoposide-induced cell death by NF-κB-mediated expression of Fas.

PubMed

Galenkamp, Koen Mo; Carriba, Paulina; Urresti, Jorge; Planells-Ferrer, Laura; Coccia, Elena; Lopez-Soriano, Joaquín; Barneda-Zahonero, Bruna; Moubarak, Rana S; Segura, Miguel F; Comella, Joan X

2015-03-19

Patients with high-risk neuroblastoma (NBL) tumors have a high mortality rate. Consequently, there is an urgent need for the development of new treatments for this condition. Targeting death receptor signaling has been proposed as an alternative to standard chemo- and radio-therapies in various tumors. In NBL, this therapeutic strategy has been largely disregarded, possibly because ~50-70% of all human NBLs are characterized by caspase-8 silencing. However, the expression of caspase-8 is detected in a significant group of NBL patients, and they could therefore benefit from treatments that induce cell death through death receptor activation. Given that cytokines, such as TNFα, are able to upregulate Fas expression, we sought to address the therapeutic relevance of co-treatment with TNFα and FasL in NBL. For the purpose of the study we used a set of eight NBL cell lines. Here we explore the cell death induced by TNFα, FasL, cisplatin, and etoposide, or a combination thereof by Hoechst staining and calcein viability assay. Further assessment of the signaling pathways involved was performed by caspase activity assays and Western blot experiments. Characterization of Fas expression levels was achieved by qRT-PCR, cell surface biotinylation assays, and cytometry. We have found that TNFα is able to increase FasL-induced cell death by a mechanism that involves the NF-κB-mediated induction of the Fas receptor. Moreover, TNFα sensitized NBL cells to DNA-damaging agents (i.e. cisplatin and etoposide) that induce the expression of FasL. Priming to FasL-, cisplatin-, and etoposide-induced cell death could only be achieved in NBLs that display TNFα-induced upregulation of Fas. Further analysis denotes that the high degree of heterogeneity between NBLs is also manifested in Fas expression and modulation thereof by TNFα. In summary, our findings reveal that TNFα sensitizes NBL cells to FasL-induced cell death by NF-κB-mediated upregulation of Fas and unveil a new

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

PubMed

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

2018-03-01

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field.

Programmed death-1 expression on HIV-1-specific CD8+ T cells is shaped by epitope specificity, T-cell receptor clonotype usage and antigen load

PubMed Central

Kløverpris, Henrik N.; McGregor, Reuben; McLaren, James E.; Ladell, Kristin; Stryhn, Anette; Koofhethile, Catherine; Brener, Jacqui; Chen, Fabian; Riddell, Lynn; Graziano, Luzzi; Klenerman, Paul; Leslie, Alasdair; Buus, Søren; Price, David A.; Goulder, Philip

2014-01-01

Objectives: Although CD8+ T cells play a critical role in the control of HIV-1 infection, their antiviral efficacy can be limited by antigenic variation and immune exhaustion. The latter phenomenon is characterized by the upregulation of multiple inhibitory receptors, such as programmed death-1 (PD-1), CD244 and lymphocyte activation gene-3 (LAG-3), which modulate the functional capabilities of CD8+ T cells. Design and methods: Here, we used an array of different human leukocyte antigen (HLA)-B∗15 : 03 and HLA-B∗42 : 01 tetramers to characterize inhibitory receptor expression as a function of differentiation on HIV-1-specific CD8+ T-cell populations (n = 128) spanning 11 different epitope targets. Results: Expression levels of PD-1, but not CD244 or LAG-3, varied substantially across epitope specificities both within and between individuals. Differential expression of PD-1 on T-cell receptor (TCR) clonotypes within individual HIV-1-specific CD8+ T-cell populations was also apparent, independent of clonal dominance hierarchies. Positive correlations were detected between PD-1 expression and plasma viral load, which were reinforced by stratification for epitope sequence stability and dictated by effector memory CD8+ T cells. Conclusion: Collectively, these data suggest that PD-1 expression on HIV-1-specific CD8+ T cells tracks antigen load at the level of epitope specificity and TCR clonotype usage. These findings are important because they provide evidence that PD-1 expression levels are influenced by peptide/HLA class I antigen exposure. PMID:24906112

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

PubMed Central

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

2015-01-01

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

Cell death proteomics database: consolidating proteomics data on cell death.

PubMed

Arntzen, Magnus Ø; Bull, Vibeke H; Thiede, Bernd

2013-05-03

Programmed cell death is a ubiquitous process of utmost importance for the development and maintenance of multicellular organisms. More than 10 different types of programmed cell death forms have been discovered. Several proteomics analyses have been performed to gain insight in proteins involved in the different forms of programmed cell death. To consolidate these studies, we have developed the cell death proteomics (CDP) database, which comprehends data from apoptosis, autophagy, cytotoxic granule-mediated cell death, excitotoxicity, mitotic catastrophe, paraptosis, pyroptosis, and Wallerian degeneration. The CDP database is available as a web-based database to compare protein identifications and quantitative information across different experimental setups. The proteomics data of 73 publications were integrated and unified with protein annotations from UniProt-KB and gene ontology (GO). Currently, more than 6,500 records of more than 3,700 proteins are included in the CDP. Comparing apoptosis and autophagy using overrepresentation analysis of GO terms, the majority of enriched processes were found in both, but also some clear differences were perceived. Furthermore, the analysis revealed differences and similarities of the proteome between autophagosomal and overall autophagy. The CDP database represents a useful tool to consolidate data from proteome analyses of programmed cell death and is available at http://celldeathproteomics.uio.no.

Decoy receptors block TRAIL sensitivity at a supracellular level: the role of stromal cells in controlling tumour TRAIL sensitivity.

PubMed

O'Leary, L; van der Sloot, A M; Reis, C R; Deegan, S; Ryan, A E; Dhami, S P S; Murillo, L S; Cool, R H; Correa de Sampaio, P; Thompson, K; Murphy, G; Quax, W J; Serrano, L; Samali, A; Szegezdi, E

2016-03-10

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a death ligand cytokine known for its cytotoxic activity against malignantly transformed cells. TRAIL induces cell death through binding to death receptors DR4 and DR5. The inhibitory decoy receptors (DcR1 and DcR2) co-expressed with death receptor 4 (DR4)/DR5 on the same cell can block the transmission of the apoptotic signal. Here, we show that DcRs also regulate TRAIL sensitivity at a supracellular level and thus represent a mechanism by which the microenvironment can diminish tumour TRAIL sensitivity. Mathematical modelling and layered or spheroid stroma-extracellular matrix-tumour cultures were used to model the tumour microenvironment. By engineering TRAIL to escape binding by DcRs, we found that DcRs do not only act in a cell-autonomous or cis-regulatory manner, but also exert trans-cellular regulation originating from stromal cells and affect tumour cells, highlighting the potent inhibitory effect of DcRs in the tumour tissue and the necessity of selective targeting of the two death-inducing TRAIL receptors to maximise efficacy.

Emodin induces apoptosis of human cervical cancer hela cells via intrinsic mitochondrial and extrinsic death receptor pathway.

PubMed

Yaoxian, Wang; Hui, Yu; Yunyan, Zhang; Yanqin, Liu; Xin, Ge; Xiaoke, Wu

2013-07-16

Emodin is a natural anthraquinone derivative isolated from the Rheum palmatum L. The aim of the present study was to investigate the effect of emodin on the apoptosis of the human cervical cancer line HeLa and to identify the mechanisms involved. Relative cell viability was assessed by MTT assay after treatment with emodin. Cell apoptosis was detected with TUNEL, Hoechst 33342 staining and quantified with flow cytometry using annexin FITC-PI staining. The percentage of apoptotic cells was 0.8, 8.2, 22.1, and 43.7%, respectively. The mRNA levels of Caspase-9, -8 and -3 detected by Real-time PCR after treatment with emodin were significantly increased. Emodin increased the protein levels of Cytochome c, Apaf-1, Fas, FasL, and FADD but decreased the protein levels of Pro-caspase-9, Pro-caspase-8 and Pro-caspase-3. We conclude that the emodin inhibited HeLa proliferation by inducing apoptosis through the intrinsic mitochondrial and extrinsic death receptor pathways.

Crystalline structure of pulverized dental calculus induces cell death in oral epithelial cells.

PubMed

Ziauddin, S M; Yoshimura, A; Montenegro Raudales, J L; Ozaki, Y; Higuchi, K; Ukai, T; Kaneko, T; Miyazaki, T; Latz, E; Hara, Y

2018-06-01

Dental calculus is a mineralized deposit attached to the tooth surface. We have shown that cellular uptake of dental calculus triggers nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation, leading to the processing of the interleukin-1β precursor into its mature form in mouse and human phagocytes. The activation of the NLRP3 inflammasome also induced a lytic form of programmed cell death, pyroptosis, in these cells. However, the effects of dental calculus on other cell types in periodontal tissue have not been investigated. The aim of this study was to determine whether dental calculus can induce cell death in oral epithelial cells. HSC-2 human oral squamous carcinoma cells, HOMK107 human primary oral epithelial cells and immortalized mouse macrophages were exposed to dental calculus or 1 of its components, hydroxyapatite crystals. For inhibition assays, the cells were exposed to dental calculus in the presence or absence of cytochalasin D (endocytosis inhibitor), z-YVAD-fmk (caspase-1 inhibitor) or glyburide (NLRP3 inflammasome inhibitor). Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) release and staining with propidium iodide. Tumor necrosis factor-α production was quantified by enzyme-linked immunosorbent assay. Oral epithelial barrier function was examined by permeability assay. Dental calculus induced cell death in HSC-2 cells, as judged by LDH release and propidium iodide staining. Dental calculus also induced LDH release from HOMK107 cells. Following heat treatment, dental calculus lost its capacity to induce tumor necrosis factor-α in mouse macrophages, but could induce LDH release in HSC-2 cells, indicating a major role of inorganic components in cell death. Hydroxyapatite crystals also induced cell death in both HSC-2 and HOMK107 cells, as judged by LDH release, indicating the capacity of crystal particles to induce cell death. Cell death induced by dental

Plant ERD2-like proteins function as endoplasmic reticulum luminal protein receptors and participate in programmed cell death during innate immunity.

PubMed

Xu, Guoyong; Li, Sizhun; Xie, Ke; Zhang, Qiang; Wang, Yan; Tang, Yang; Liu, Dong; Hong, Yiguo; He, Chenyang; Liu, Yule

2012-10-01

The hypersensitive response (HR), a form of programmed cell death (PCD), is a tightly regulated innate immune response in plants that is hypothesized to restrict pathogen growth and disease development. Although considerable efforts have been made to understand HR PCD, it remains unknown whether the retrograde pathway from the Golgi to the endoplasmic reticulum (ER) is involved. Here we provide direct genetic evidence that two Nicotiana benthamiana homologs, ERD2a and ERD2b, function as ER luminal protein receptors and participate in HR PCD. Virus-induced gene silencing (VIGS) of ERD2a and/or ERD2b caused escape of ER-resident proteins from the ER, and resulted in plants that were more sensitive to ER stress. Silencing of ERD2b delayed HR PCD induced by the non-host pathogens Xanthomonas oryzae pv. oryzae and Pseudomonas syringae pv. tomato DC3000. However, both silencing of ERD2a and co-silencing of ERD2a and ERD2b exacerbated HR PCD. Individual and combined suppression of ERD2a and ERD2b exaggerated R gene-mediated cell death. Nevertheless, silencing of ERD2a and/or ERD2b had no detectable effects on bacterial growth. Furthermore, VIGS of several putative ligands of ERD2a/2b, including the ER quality control (ERQC) component genes BiP, CRT3 and UGGT, had different effects on HR PCD induced by different pathogens. This indicates that immunity-related cell death pathways are separate with respect to the genetic requirements for these ERQC components. These results suggest that ERD2a and ERD2b function as ER luminal protein receptors to ensure ERQC and alleviate ER stress, thus affecting HR PCD during the plant innate immune response. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

Cell death in the thymus--it' s all a matter of contacts.

PubMed

Minter, Lisa M; Osborne, Barbara A

2003-06-01

Apoptosis, or programmed cell death, plays a critical role in shaping the T cell repertoire, deleting unproductive as well as potentially autoreactive T cells. Our understanding of how thymocyte apoptosis is regulated is continually evolving, as new essential modulators of this process are discovered. A conundrum that remains, however, is how signaling through essentially the same receptors and cascades evokes distinct biological responses: death by neglect, positive or negative selection. We hypothesize that the immunological synapse (IS) may be critical to transducing survival signals during thymocyte development, and suggest that factors affecting IS assembly may also influence T cell selection.

Pelle Modulates dFoxO-Mediated Cell Death in Drosophila.

PubMed

Wu, Chenxi; Chen, Yujun; Wang, Feng; Chen, Changyan; Zhang, Shiping; Li, Chaojie; Li, Wenzhe; Wu, Shian; Xue, Lei

2015-10-01

Interleukin-1 receptor-associated kinases (IRAKs) are crucial mediators of the IL-1R/TLR signaling pathways that regulate the immune and inflammation response in mammals. Recent studies also suggest a critical role of IRAKs in tumor development, though the underlying mechanism remains elusive. Pelle is the sole Drosophila IRAK homolog implicated in the conserved Toll pathway that regulates Dorsal/Ventral patterning, innate immune response, muscle development and axon guidance. Here we report a novel function of pll in modulating apoptotic cell death, which is independent of the Toll pathway. We found that loss of pll results in reduced size in wing tissue, which is caused by a reduction in cell number but not cell size. Depletion of pll up-regulates the transcription of pro-apoptotic genes, and triggers caspase activation and cell death. The transcription factor dFoxO is required for loss-of-pll induced cell death. Furthermore, loss of pll activates dFoxO, promotes its translocation from cytoplasm to nucleus, and up-regulates the transcription of its target gene Thor/4E-BP. Finally, Pll physically interacts with dFoxO and phosphorylates dFoxO directly. This study not only identifies a previously unknown physiological function of pll in cell death, but also shed light on the mechanism of IRAKs in cell survival/death during tumorigenesis.

The chalcone 2'-hydroxy-4',5'-dimethoxychalcone activates death receptor 5 pathway and leads to apoptosis in human nonsmall cell lung cancer cells.

PubMed

Yang, Lina; Su, Ling; Cao, Congmei; Xu, Linyan; Zhong, Diansheng; Xu, Lijia; Liu, Xiangguo

2013-06-01

Natural chalcones have been proved to inhibit cancer cells with therapeutic potential, but the underlying molecular mechanism is still largely unexplored. Here, we identified a novel chalcone, 2'-hydroxy-4',5'-dimethoxychalcone (HDMC) and demonstrated that HDMC induced apoptosis in various nonsmall cell lung cancer cells. Further study showed that HDMC elevated cellular reactive oxygen species (ROS) levels, thus inducing expressions of ATF4 and C/EBP homologous protein (CHOP). Then, death receptor 5 (DR5) was upregulated through ATF4-CHOP axis and eventually resulted in apoptosis. We also found that downregulation of c-FLIPL contributed to HDMC-induced apoptosis. In conclusion, HDMC induces apoptosis in human nonsmall cell lung cancer cells via activation of DR5 signaling pathway, and ROS-mediated ATF4-CHOP axis is involved in the process. Our results further supported the potential for HDMC to be developed as a new antitumor agent for cancer therapy or chemoprevention. Copyright © 2013 International Union of Biochemistry and Molecular Biology, Inc.

Signaling via the transcriptionally regulated activin receptor 2B is a novel mediator of neuronal cell death during chicken ciliary ganglion development.

PubMed

Koszinowski, S; Buss, K; Kaehlcke, K; Krieglstein, K

2015-04-01

The TGF-β ligand superfamily members activin A and BMP control important aspects of embryonic neuronal development and differentiation. Both are known to bind to activin receptor subtypes IIA (ActRIIA) and IIB, while in the avian ciliary ganglion (CG), so far only ActRIIA-expression has been described. We show that the expression of ACVR2B, coding for the ActRIIB, is tightly regulated during CG development and the knockdown of ACVR2B expression leads to a deregulation in the execution of neuronal apoptosis and therefore affects ontogenetic programmed cell death in vivo. While the differentiation of choroid neurons was impeded in the knockdown, pointing toward a reduction in activin A-mediated neural differentiation signaling, naturally occurring neuronal cell death in the CG was not prevented by follistatin treatment. Systemic injections of the BMP antagonist noggin, on the other hand, reduced the number of apoptotic neurons to a similar extent as ACVR2B knockdown. We therefore propose a novel pathway in the regulation of CG neuron ontogenetic programmed cell death, which could be mediated by BMP and signals via the ActRIIB. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Ethylene Insensitivity Modulates Ozone-Induced Cell Death in Birch1

PubMed Central

Vahala, Jorma; Ruonala, Raili; Keinänen, Markku; Tuominen, Hannele; Kangasjärvi, Jaakko

2003-01-01

We have used genotypic variation in birch (Betula pendula Roth) to investigate the roles of ozone (O3)-induced ethylene (ET), jasmonic acid, and salicylic acid in the regulation of tissue tolerance to O3. Of these hormones, ET evolution correlated best with O3-induced cell death. Disruption of ET perception by transformation of birch with the dominant negative mutant allele etr1-1 of the Arabidopsis ET receptor gene ETR1 or blocking of ET perception with 1-methylcyclopropene reduced but did not completely prevent the O3-induced cell death, when inhibition of ET biosynthesis with aminooxyacetic acid completely abolished O3 lesion formation. This suggests the presence of an ET-signaling-independent but ET biosynthesis-dependent component in the ET-mediated stimulation of cell death in O3-exposed birch. Functional ET signaling was required for the O3 induction of the gene encoding β-cyanoalanine synthase, which catalyzes detoxification of the cyanide formed during ET biosynthesis. The results suggest that functional ET signaling is required to protect birch from the O3-induced cell death and that a decrease in ET sensitivity together with a simultaneous, high ET biosynthesis can potentially cause cell death through a deficient detoxification of cyanide. PMID:12746524

The ubiquitin-homology protein, DAP-1, associates with tumor necrosis factor receptor (p60) death domain and induces apoptosis.

PubMed

Liou, M L; Liou, H C

1999-04-09

The tumor necrosis factor receptor, p60 (TNF-R1), transduces death signals via the association of its cytoplasmic domain with several intracellular proteins. By screening a mammalian cDNA library using the yeast two-hybrid cloning technique, we isolated a ubiquitin-homology protein, DAP-1, which specifically interacts with the cytoplasmic death domain of TNF-R1. Sequence analysis reveals that DAP-1 shares striking sequence homology with the yeast SMT3 protein that is essential for the maintenance of chromosome integrity during mitosis (Meluh, P. B., and Koshland, D. (1995) Mol. Biol. Cell 6, 793-807). DAP-1 is nearly identical to PIC1, a protein that interacts with the PML tumor suppressor implicated in acute promyelocytic leukemia (Boddy, M. N., Howe, K., Etkin, L. D., Solomon, E., and Freemont, P. S. (1996) Oncogene 13, 971-982), and the sentrin protein, which associates with the Fas death receptor (Okura, T., Gong, L., Kamitani, T., Wada, T., Okura, I., Wei, C. F., Chang, H. M., and Yeh, E. T. (1996) J. Immunol. 157, 4277-4281). The in vivo interaction between DAP-1 and TNF-R1 was further confirmed in mammalian cells. In transient transfection assays, overexpression of DAP-1 suppresses NF-kappaB/Rel activity in 293T cells, a human kidney embryonic carcinoma cell line. Overexpression of either DAP-1 or sentrin causes apoptosis of TNF-sensitive L929 fibroblast cell line, as well as TNF-resistant osteosarcoma cell line, U2OS. Furthermore, the dominant negative Fas-associated death domain protein (FADD) protein blocks the cell death induced by either DAP-1 or FADD. Collectively, these observations highly suggest a role for DAP-1 in mediating TNF-induced cell death signaling pathways, presumably through the recruitment of FADD death effector.

Ursodeoxycholic acid effectively kills drug-resistant gastric cancer cells through induction of autophagic death.

PubMed

Lim, Sung-Chul; Han, Song Iy

2015-09-01

Carcinoma cells that have acquired drug resistance often exhibit cross-resistance to various other cytotoxic stimuli. Here, we investigated the effects of ursodeoxycholic acid (UDCA), a gastrointestinal tumor-suppressor, on a cisplatin‑resistant SNU601 gastric cancer subline (SNU601/R). While other anticancer drugs, including L-OHP, etoposide, and death ligand TRAIL, had minimal effects on the viability of these resistant cells, they were sensitive to UDCA. The UDCA‑induced reduction in the viability of the SNU601/R cells was accomplished through autophagy while the primary means of cell death in the parental SNU601 cells (SNU601/WT) was apoptosis. Previously, we demonstrated that the UDCA-triggered apoptosis of gastric cancer cells was regulated by a cell surface death receptor, TRAIL-R2/DR5, which was upregulated and re-distributed on lipid rafts. The UDCA stimulation of TRAIL-R2/DR5 also occurred in the SNU601/R cells despite the lack of apoptosis. In the present study, we found that CD95/Fas, another cell surface death receptor, was also translocated into lipid rafts in response to UDCA although it was not involved in the decrease in cell viability. Specifically, raft relocalization of CD95/Fas was triggered by UDCA in the SNU601/WT cells in which apoptosis occurred, but not in the SNU601/R cells where autophagic death occurred. Notably, UDCA reduced ATG5 levels, an essential component of autophagy, in the SNU601/WT, but not in the SNU601/R cell line. Moreover, in CD95/Fas-silenced SNU601/WT cells, UDCA did not decrease ATG5 levels and induced autophagic cell death rather than apoptosis. These results imply that raft‑distributed CD95/Fas may support UDCA-induced apoptosis via downregulation of ATG5 levels, preventing the autophagic pathway. Taken together, these results suggest that UDCA induces both apoptotic and autophagic cell death depending on the intracellular signaling environment, thereby conferring the advantage to overcome drug resistance

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

Prior irradiation results in elevated programmed cell death protein 1 (PD-1) in T cells.

PubMed

Li, Deguan; Chen, Renxiang; Wang, Yi-Wen; Fornace, Albert J; Li, Heng-Hong

2018-05-01

In this study we addressed the question whether radiation-induced adverse effects on T cell activation are associated with alterations of T cell checkpoint receptors. Expression levels of checkpoint receptors on T cell subpopulations were analyzed at multiple post-radiation time points ranging from one to four weeks in mice receiving a single fraction of 1 or 4 Gy of γ-ray. T cell activation associated metabolic changes were assessed. Our results showed that prior irradiation resulted in significant elevated expression of programmed cell death protein 1 (PD-1) in both CD4+ and CD8+ populations, at all three post-radiation time points. T cells with elevated PD-1 mostly were either central memory or naïve cells. In addition, the feedback induction of PD-1 expression in activated T cells declined after radiation. Taken together, the elevated PD-1 level observed at weeks after radiation exposure is connected to T cell dysfunction. Recent preclinical and clinical studies have showed that a combination of radiotherapy and T cell checkpoint blockade immunotherapy including targeting the programmed death-ligand 1 (PD-L1)/PD-1 axis may potentiate the antitumor response. Understanding the dynamic changes in PD-1 levels in T cells after radiation should help in the development of a more effective therapeutic strategy.

Programmed death receptor-1/programmed death receptor ligand-1 blockade after transient lymphodepletion to treat myeloma.

PubMed

Kearl, Tyce J; Jing, Weiqing; Gershan, Jill A; Johnson, Bryon D

2013-06-01

Early phase clinical trials targeting the programmed death receptor-1/ligand-1 (PD-1/PD-L1) pathway to overcome tumor-mediated immunosuppression have reported promising results for a variety of cancers. This pathway appears to play an important role in the failure of immune reactivity to malignant plasma cells in multiple myeloma patients, as the tumor cells express relatively high levels of PD-L1, and T cells show increased PD-1 expression. In the current study, we demonstrate that PD-1/PD-L1 blockade with a PD-L1-specific Ab elicits rejection of a murine myeloma when combined with lymphodepleting irradiation. This particular combined approach by itself has not previously been shown to be efficacious in other tumor models. The antitumor effect of lymphodepletion/anti-PD-L1 therapy was most robust when tumor Ag-experienced T cells were present either through cell transfer or survival after nonmyeloablative irradiation. In vivo depletion of CD4 or CD8 T cells completely eliminated antitumor efficacy of the lymphodepletion/anti-PD-L1 therapy, indicating that both T cell subsets are necessary for tumor rejection. Elimination of myeloma by T cells occurs relatively quickly as tumor cells in the bone marrow were nearly nondetectable by 5 d after the first anti-PD-L1 treatment, suggesting that antimyeloma reactivity is primarily mediated by preactivated T cells, rather than newly generated myeloma-reactive T cells. Anti-PD-L1 plus lymphodepletion failed to improve survival in two solid tumor models, but demonstrated significant efficacy in two hematologic malignancy models. In summary, our results support the clinical testing of lymphodepletion and PD-1/PD-L1 blockade as a novel approach for improving the survival of patients with multiple myeloma.

Role of Bax in death of uninfected retinal cells during murine cytomegalovirus retinitis.

PubMed

Mo, Juan; Marshall, Brendan; Covar, Jason; Zhang, Nancy Y; Smith, Sylvia B; Atherton, Sally S; Zhang, Ming

2014-10-08

Extensive death of uninfected bystander neuronal cells is an important component of the pathogenesis of cytomegalovirus retinitis. Our previous results have shown that caspase 3-dependent and -independent pathways are involved in death of uninfected bystander cells during murine cytomegalovirus (MCMV) retinitis and also that Bcl-2, an important inhibitor of apoptosis via the Bax-mediated mitochondrial pathway, is downregulated during this process. The purpose of this study was to determine whether Bax-mediated mitochondrial damage has a significant role in the death of uninfected retinal cells. BALB/c mice, Bax(-/-) mice, or Bax(+/+) mice were immunosuppressed with methylprednisolone and infected with 5 × 10(3) plaque-forming units (PFU) of the K181 strain of MCMV via the supraciliary route. Injected eyes were analyzed by plaque assay, electron microscopy, hematoxylin and eosin (H&E) staining, TUNEL assay, Western blot (for caspase 3, caspase 12, Bax, receptor interacting protein-1 [RIP1] and receptor interacting protein-3 [RIP3]), as well as immunohistochemical staining for MCMV early antigen and cleaved caspase 3. Significantly more Bax was detected in mitochondrial fractions of MCMV-infected eyes than in mitochondrial fractions of mock-infected control eyes. Furthermore, the level of cleaved caspase 3 was significantly lower in MCMV-infected Bax(-/-) eyes than in MCMV-infected Bax(+/+) eyes. However, more caspase 3-independent cell death of uninfected bystander retinal cells and more cleaved RIP1 were observed in Bax(-/-) than in Bax(+/+) eyes. During MCMV retinitis, Bax is activated and has an important role in death of uninfected bystander retinal cells by caspase 3-dependent apoptosis. Although the exact mechanism remains to be deciphered, active Bax might also prevent death of some types of uninfected retinal cells by a caspase 3-independent pathway. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Role of Bax in Death of Uninfected Retinal Cells During Murine Cytomegalovirus Retinitis

PubMed Central

Mo, Juan; Marshall, Brendan; Covar, Jason; Zhang, Nancy Y.; Smith, Sylvia B.; Atherton, Sally S.; Zhang, Ming

2014-01-01

Purpose. Extensive death of uninfected bystander neuronal cells is an important component of the pathogenesis of cytomegalovirus retinitis. Our previous results have shown that caspase 3–dependent and –independent pathways are involved in death of uninfected bystander cells during murine cytomegalovirus (MCMV) retinitis and also that Bcl-2, an important inhibitor of apoptosis via the Bax-mediated mitochondrial pathway, is downregulated during this process. The purpose of this study was to determine whether Bax-mediated mitochondrial damage has a significant role in the death of uninfected retinal cells. Methods. BALB/c mice, Bax−/− mice, or Bax+/+ mice were immunosuppressed with methylprednisolone and infected with 5 × 103 plaque-forming units (PFU) of the K181 strain of MCMV via the supraciliary route. Injected eyes were analyzed by plaque assay, electron microscopy, hematoxylin and eosin (H&E) staining, TUNEL assay, Western blot (for caspase 3, caspase 12, Bax, receptor interacting protein-1 [RIP1] and receptor interacting protein-3 [RIP3]), as well as immunohistochemical staining for MCMV early antigen and cleaved caspase 3. Results. Significantly more Bax was detected in mitochondrial fractions of MCMV-infected eyes than in mitochondrial fractions of mock-infected control eyes. Furthermore, the level of cleaved caspase 3 was significantly lower in MCMV-infected Bax−/− eyes than in MCMV-infected Bax+/+ eyes. However, more caspase 3–independent cell death of uninfected bystander retinal cells and more cleaved RIP1 were observed in Bax−/− than in Bax+/+ eyes. Conclusions. During MCMV retinitis, Bax is activated and has an important role in death of uninfected bystander retinal cells by caspase 3–dependent apoptosis. Although the exact mechanism remains to be deciphered, active Bax might also prevent death of some types of uninfected retinal cells by a caspase 3–independent pathway. PMID:25298417

Enhancement of Glioma Radiotherapy and Chemotherapy Response With Targeted Antibody Therapy Against Death Receptor 5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiveash, John B.; Gillespie, G. Yancey; Oliver, Patsy G.

2008-06-01

Purpose: TRA-8 is an agonistic mouse monoclonal antibody that binds to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor 5, which induces apoptosis in cancer cells through a caspase-8-dependent mechanism. We investigated the ability of TRA-8 to augment the radiotherapy (RT) and chemotherapy response of human glioma cells in vitro and in vivo. Methods and Materials: The in vitro cytotoxicity of TRA-8 and temozolomide (Tmz) or RT was examined using adenosine triphosphate-dependent viability and clonogenic survival assays with five glioma cell lines. Death receptor 5 expression was determined by flow cytometry. In vivo studies included subcutaneous and intracranial xenograft modelsmore » testing various combination treatments, including RT, Tmz, and TRA-8. Results: TRA-8, combined with Tmz or RT, produced enhanced cytotoxicity against five glioma cell lines compared with the use of the individual agents alone. Death receptor 5 upregulation occurred in response to RT. Complete tumor regression in the subcutaneous experiments was the most common in animals that received combination therapy with TRA-8/Tmz/RT. TRA-8 enhanced tumor growth delay in combination with RT or Tmz. TRA-8 alone had limited activity against intracranial tumors. In contrast, the median survival of mice treated with TRA-8/Tmz/RT was significantly greater than the control or TRA-8-alone-treated mice. The median survival of the mice treated with TRA-8/Tmz/RT or chemoradiotherapy only was significantly greater than the control or TRA-8-treated mice. A trend toward improved survival was observed between TRA-8/Tmz/RT-treated and Tmz/RT-treated mice. Conclusions: These preliminary findings support the hypothesis that TRA-8 will augment the RT and chemotherapy response in gliomas. A humanized version of TRA-8 is being evaluated in a Phase II clinical trial.« less

Death receptors DR6 and TROY regulate brain vascular development.

PubMed

Tam, Stephen J; Richmond, David L; Kaminker, Joshua S; Modrusan, Zora; Martin-McNulty, Baby; Cao, Tim C; Weimer, Robby M; Carano, Richard A D; van Bruggen, Nick; Watts, Ryan J

2012-02-14

Signaling events that regulate central nervous system (CNS) angiogenesis and blood-brain barrier (BBB) formation are only beginning to be elucidated. By evaluating the gene expression profile of mouse vasculature, we identified DR6/TNFRSF21 and TROY/TNFRSF19 as regulators of CNS-specific angiogenesis in both zebrafish and mice. Furthermore, these two death receptors interact both genetically and physically and are required for vascular endothelial growth factor (VEGF)-mediated JNK activation and subsequent human brain endothelial sprouting in vitro. Increasing beta-catenin levels in brain endothelium upregulate DR6 and TROY, indicating that these death receptors are downstream target genes of Wnt/beta-catenin signaling, which has been shown to be required for BBB development. These findings define a role for death receptors DR6 and TROY in CNS-specific vascular development. Copyright © 2012 Elsevier Inc. All rights reserved.

Autonomous rexinoid death signaling is suppressed by converging signaling pathways in immature leukemia cells.

PubMed

Benoit, G R; Flexor, M; Besançon, F; Altucci, L; Rossin, A; Hillion, J; Balajthy, Z; Legres, L; Ségal-Bendirdjian, E; Gronemeyer, H; Lanotte, M

2001-07-01

On their own, retinoid X receptor (RXR)-selective ligands (rexinoids) are silent in retinoic acid receptor (RAR)-RXR heterodimers, and no selective rexinoid program has been described as yet in cellular systems. We report here on the rexinoid signaling capacity that triggers apoptosis of immature promyelocytic NB4 cells as a default pathway in the absence of survival factors. Rexinoid-induced apoptosis displays all features of bona fide programmed cell death and is inhibited by RXR, but not RAR antagonists. Several types of survival signals block rexinoid-induced apoptosis. RARalpha agonists switch the cellular response toward differentiation and induce the expression of antiapoptosis factors. Activation of the protein kinase A pathway in the presence of rexinoid agonists induces maturation and blocks immature cell apoptosis. Addition of nonretinoid serum factors also blocks cell death but does not induce cell differentiation. Rexinoid-induced apoptosis is linked to neither the presence nor stability of the promyelocytic leukemia-RARalpha fusion protein and operates also in non-acute promyelocytic leukemia cells. Together our results support a model according to which rexinoids activate in certain leukemia cells a default death pathway onto which several other signaling paradigms converge. This pathway is entirely distinct from that triggered by RAR agonists, which control cell maturation and postmaturation apoptosis.

Spinosad induces programmed cell death involves mitochondrial dysfunction and cytochrome C release in Spodoptera frugiperda Sf9 cells.

PubMed

Yang, Mingjun; Wang, Bo; Gao, Jufang; Zhang, Yang; Xu, Wenping; Tao, Liming

2017-02-01

Spinosad, a reduced-risk insecticide, acts on the nicotinic acetylcholine receptors and the gamma-aminobutyric acid receptor in the nervous system of target insects. However, its mechanism of action in non-neural insect cells is unclear. This study aimed to evaluate mitochondrial functional changes associated with spinosad in Spodoptera frugiperda (Sf9) insect cells. Our results indicate that in Sf9 cells, spinosad induces programmed cell death and mitochondrial dysfunction through enhanced reactive oxygen species production, mitochondrial permeability transition pore (mPTP) opening, and mitochondrial membrane potential collapse, eventually leading to cytochrome C release and apoptosis. The cytochrome C release induced by spinosad treatment was partly inhibited by the mPTP inhibitors cyclosporin A and bongkrekic acid. Subsequently, we found that spinosad downregulated Bcl-2 expression and upregulated p53 and Bax expressions, activated caspase-9 and caspase-3, and triggered PARP cleavage in Sf9 cells. These findings suggested that spinosad-induced programmed cell death was modulated by mitochondrial dysfunction and cytochrome C release. Copyright © 2016 Elsevier Ltd. All rights reserved.

Shedding of Microvesicles from Microglia Contributes to the Effects Induced by Metabotropic Glutamate Receptor 5 Activation on Neuronal Death.

PubMed

Beneventano, Martina; Spampinato, Simona F; Merlo, Sara; Chisari, Mariangela; Platania, Paola; Ragusa, Marco; Purrello, Michele; Nicoletti, Ferdinando; Sortino, Maria Angela

2017-01-01

Metabotropic glutamate (mGlu) receptor 5 is involved in neuroinflammation and has been shown to mediate reduced inflammation and neurotoxicity and to modify microglia polarization. On the other hand, blockade of mGlu5 receptor results in inhibition of microglia activation. To dissect this controversy, we investigated whether microvesicles (MVs) released from microglia BV2 cells could contribute to the communication between microglia and neurons and whether this interaction was modulated by mGlu5 receptor. Activation of purinergic ionotropic P2X7 receptor with the stable ATP analog benzoyl-ATP (100 μM) caused rapid MVs shedding from BV2 cells. Ionic currents through P2X7 receptor increased in BV2 cells pretreated for 24 h with the mGlu5 receptor agonist CHPG (200 μM) as by patch-clamp recording. This increase was blunted when microglia cells were activated by exposure to lipopolysaccharide (LPS; 0.1 μg/ml for 6 h). Accordingly, a greater amount of MVs formed after CHPG treatment, an effect prevented by the mGlu5 receptor antagonist MTEP (100 μM), as measured by expression of flotillin, a membrane protein enriched in MVs. Transferred MVs were internalized by SH-SY5Y neurons where they did not modify neuronal death induced by a low concentration of rotenone (0.1 μM for 24 h), but significantly increased rotenone neurotoxicity when shed from CHPG-treated BV2 cells. miR146a was increased in CHPG-treated MVs, an effect concealed in MVs from LPS-activated BV2 cells that showed per se an increase in miRNA146a levels. The present data support a role for microglia-shed MVs in mGlu5-mediated modulation of neuronal death and identify miRNAs as potential critical mediators of this interaction.

Shedding of Microvesicles from Microglia Contributes to the Effects Induced by Metabotropic Glutamate Receptor 5 Activation on Neuronal Death

PubMed Central

Beneventano, Martina; Spampinato, Simona F.; Merlo, Sara; Chisari, Mariangela; Platania, Paola; Ragusa, Marco; Purrello, Michele; Nicoletti, Ferdinando; Sortino, Maria Angela

2017-01-01

Metabotropic glutamate (mGlu) receptor 5 is involved in neuroinflammation and has been shown to mediate reduced inflammation and neurotoxicity and to modify microglia polarization. On the other hand, blockade of mGlu5 receptor results in inhibition of microglia activation. To dissect this controversy, we investigated whether microvesicles (MVs) released from microglia BV2 cells could contribute to the communication between microglia and neurons and whether this interaction was modulated by mGlu5 receptor. Activation of purinergic ionotropic P2X7 receptor with the stable ATP analog benzoyl-ATP (100 μM) caused rapid MVs shedding from BV2 cells. Ionic currents through P2X7 receptor increased in BV2 cells pretreated for 24 h with the mGlu5 receptor agonist CHPG (200 μM) as by patch-clamp recording. This increase was blunted when microglia cells were activated by exposure to lipopolysaccharide (LPS; 0.1 μg/ml for 6 h). Accordingly, a greater amount of MVs formed after CHPG treatment, an effect prevented by the mGlu5 receptor antagonist MTEP (100 μM), as measured by expression of flotillin, a membrane protein enriched in MVs. Transferred MVs were internalized by SH-SY5Y neurons where they did not modify neuronal death induced by a low concentration of rotenone (0.1 μM for 24 h), but significantly increased rotenone neurotoxicity when shed from CHPG-treated BV2 cells. miR146a was increased in CHPG-treated MVs, an effect concealed in MVs from LPS-activated BV2 cells that showed per se an increase in miRNA146a levels. The present data support a role for microglia-shed MVs in mGlu5-mediated modulation of neuronal death and identify miRNAs as potential critical mediators of this interaction. PMID:29170640

In Glaucoma the Upregulated Truncated TrkC.T1 Receptor Isoform in Glia Causes Increased TNF-α Production, Leading to Retinal Ganglion Cell Death

PubMed Central

Bai, Yujing; Shi, ZhiHua; Zhuo, Yehong; Liu, Jing; Malakhov, Andrey; Ko, Eunhwa; Burgess, Kevin; Schaefer, Henry; Esteban, Pedro F.; Tessarollo, Lino; Saragovi, H. Uri

2010-01-01

Purpose. Glaucoma is a distinct neuropathy characterized by the chronic and progressive death of retinal ganglion cells (RGCs). The etiology of RGC death remains unknown. Risk factors for glaucomatous RGC death are elevated intraocular pressure and glial production of tumor necrosis factor-alpha (TNF-α). Previously, the authors showed that glaucoma causes a rapid upregulation of a neurotrophin receptor truncated isoform lacking the kinase domain, TrkC.T1, in retina. Here they examined the biological role of TrkC.T1 during glaucoma progression. Methods. Rat and mouse models of chronic ocular hypertension were used. Immunofluorescence Western blot analysis and in situ mRNA hybridization were used to identify cells upregulating TrkC.T1. A genetic model of engineered mice lacking TrkC.T1 (TrkC.T1−/−) was used to validate a role for this receptor in glaucoma. Pharmacologic studies were conducted to evaluate intravitreal delivery of agonists or antagonists of TrkC.T1, compared with controls, during glaucoma. Surviving RGCs were quantified by retrograde-labeling techniques. Production of neurotoxic TNF-α and α2 macroglobulin were quantified. Results. TrkC.T1 was upregulated in retinal glia, with a pattern similar to that of TNF-α. TrkC.T1−/− mice had normal retinas. However, during experimental glaucoma, TrkC.T1−/− mice had lower rates of RGC death and produced less TNF-α than wild-type littermates. In rats with glaucoma, the pharmacologic use of TrkC antagonists delayed RGC death and reduced the production of retinal TNF-α. Conclusions. TrkC.T1 is implicated in glaucomatous RGC death through the control of glial TNF-α production. Overall, the data point to a paracrine mechanism whereby elevated intraocular pressure upregulated glial TrkC.T1 expression in glia; TrkC.T1 controlled glial TNF-α production, and TNF-α caused RGC death. PMID:20574020

Emodin induces apoptosis of human cervical cancer hela cells via intrinsic mitochondrial and extrinsic death receptor pathway

PubMed Central

2013-01-01

Background Emodin is a natural anthraquinone derivative isolated from the Rheum palmatum L. Aim: The aim of the present study was to investigate the effect of emodin on the apoptosis of the human cervical cancer line HeLa and to identify the mechanisms involved. Methods Relative cell viability was assessed by MTT assay after treatment with emodin. Cell apoptosis was detected with TUNEL, Hoechst 33342 staining and quantified with flow cytometry using annexin FITC-PI staining. Results The percentage of apoptotic cells was 0.8, 8.2, 22.1, and 43.7%, respectively. The mRNA levels of Caspase-9, -8 and −3 detected by Real-time PCR after treatment with emodin were significantly increased. Emodin increased the protein levels of Cytochome c, Apaf-1, Fas, FasL, and FADD but decreased the protein levels of Pro-caspase-9, Pro-caspase-8 and Pro-caspase-3. Conclusion We conclude that the emodin inhibited HeLa proliferation by inducing apoptosis through the intrinsic mitochondrial and extrinsic death receptor pathways. PMID:23866157

Tumor necrosis factor (TNF) biology and cell death.

PubMed

Bertazza, Loris; Mocellin, Simone

2008-01-01

Tumor necrosis factor (TNF) was the first cytokine to be used in humans for cancer therapy. However, its role in the treatment of cancer patients is debated. Most uncertainties in this field stem from the knowledge that the pathways directly activated or indirectly affected upon TNF engagement with its receptors can ultimately lead to very different outcomes in terms of cell survival. In this article, we summarize the fundamental molecular biology aspects of this cytokine. Such a basis is a prerequisite to critically approach the sometimes conflicting preclinical and clinical findings regarding the relationship between TNF, tumor biology and anticancer therapy. Although the last decade has witnessed remarkable advances in this field, we still do not know in detail how cells choose between life and death after TNF stimulation. Understanding this mechanism will not only shed new light on the physiological significance of TNF-driven programmed cell death but also help investigators maximize the anticancer potential of this cytokine.

Pathophysiological roles of P2 receptors in glial cells.

PubMed

Abbracchio, Maria P; Verderio, Claudia

2006-01-01

Extracellular nucleotides act through specific receptors on target cells: the seven ionotropic P2X and the eight G protein-coupled P2Y receptors. All these receptors are expressed by brain astroglia and microglia. In astrocytes, P2 receptors have been implicated in short-term calcium-dependent cell-cell communication. Upon mechanical stimulation or activation by other transmitters, astrocytes release ATP and respond to ATP with a propagating wave of intracellular calcium increases, allowing a homotypic astrocyte-astrocyte communication, as well as an heterotypic signalling which also involves neurons, oligodendrocytes and microglia. Astrocytic P2 receptors also mediate reactive astrogliosis, a reaction contributing to neuronal death in neurodegenerative diseases. Signalling leading to inflammatory astrogliosis involves induction of cyclo-oxygenase 2 through stimulation of ERK1,2 and of the transcriptional factors AP-1 and NF-kappaB. Microglia also express several P2 receptors linked to intracellular calcium increases. P2 receptor subtypes are differentially regulated by typical proinflammatory signals for these cells (e.g. lipopolysaccharide), suggesting specific roles in brain immune responses. Globally, these findings highlight the roles of P2 receptors in glial cell pathophysiology suggesting a contribution to neurodegenerative diseases characterized by excessive gliosis and neuro-inflammation. They also open up the possibility of modulating brain damage by ligands selectively targeting the specific P2 receptor subtypes involved in the gliotic response.

Estrogen reduces endoplasmic reticulum stress to protect against glucotoxicity induced-pancreatic β-cell death.

PubMed

Kooptiwut, Suwattanee; Mahawong, Pitchnischa; Hanchang, Wanthanee; Semprasert, Namoiy; Kaewin, Suchada; Limjindaporn, Thawornchai; Yenchitsomanus, Pa-Thai

2014-01-01

Estrogen can improve glucose homeostasis not only in diabetic rodents but also in humans. However, the molecular mechanism by which estrogen prevents pancreatic β-cell death remains unclear. To investigate this issue, INS-1 cells, a rat insulinoma cell line, were cultured in medium with either 11.1mM or 40mM glucose in the presence or the absence of estrogen. Estrogen significantly reduced apoptotic β-cell death by decreasing nitrogen-induced oxidative stress and the expression of the ER stress markers GRP 78, ATF6, P-PERK, PERK, uXBP1, sXBP1, and CHOP in INS-1 cells after prolonged culture in medium with 40mM glucose. In contrast, estrogen increased the expression of survival proteins, including sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA-2), Bcl-2, and P-p38, in INS-1 cells after prolonged culture in medium with 40mM glucose. The cytoprotective effect of estrogen was attenuated by addition of the estrogen receptor (ERα and ERβ) antagonist ICI 182,780 and the estrogen membrane receptor inhibitor G15. We showed that estrogen decreases not only oxidative stress but also ER stress to protect against 40mM glucose-induced pancreatic β-cell death. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dead Cert: Measuring Cell Death.

PubMed

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

2016-12-01

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

Melatonin partially protects 661W cells from H2O2-induced death by inhibiting Fas/FasL-caspase-3.

PubMed

Sánchez-Bretaño, Aída; Baba, Kenkichi; Janjua, Uzair; Piano, Ilaria; Gargini, Claudia; Tosini, Gianluca

2017-01-01

Previous studies have shown that melatonin (MEL) signaling is involved in the modulation of photoreceptor viability during aging. Recent work by our laboratory suggested that MEL may protect cones by modulating the Fas/FasL-caspase-3 pathway. In this study, we first investigated the presence of MEL receptors (MT 1 and MT 2 ) in 661W cells, then whether MEL can prevent H 2 O 2 -induced cell death, and last, through which pathway MEL confers protection. The mRNA and proteins of the MEL receptors were detected with quantitative PCR (q-PCR) and immunocytochemistry, respectively. To test the protective effect of MEL, 661W cells were treated with H 2 O 2 for 2 h in the presence or absence of MEL, a MEL agonist, and an antagonist. To study the pathways involved in H 2 O 2 -mediated cell death, a Fas/FasL antagonist was used before the exposure to H 2 O 2 . Finally, Fas/FasL and caspase-3 mRNA was analyzed with q-PCR and immunocytochemistry in cells treated with H 2 O 2 and/or MEL. Cell viability was analyzed by using Trypan Blue. Both MEL receptors (MT 1 and MT 2 ) were detected at the mRNA and protein levels in 661W cells. MEL partially prevented H 2 O 2 -mediated cell death (20-25%). This effect was replicated with IIK7 (a melatonin receptor agonist) when used at a concentration of 1 µM. Preincubation with luzindole (a melatonin receptor antagonist) blocked MEL protection. Kp7-6, an antagonist of Fas/FasL, blocked cell death caused by H 2 O 2 similarly to what was observed for MEL. Fas, FasL, and caspase-3 expression was increased in cells treated with H 2 O 2 , and this effect was prevented by MEL. Finally, MEL treatment partially prevented the activation of caspase-3 caused by H 2 O 2 . The results demonstrate that MEL receptors are present and functional in 661W cells. MEL can prevent photoreceptor cell death induced by H 2 O 2 via the inhibition of the proapoptotic pathway Fas/FasL-caspase-3.

Necroptosis-like Neuronal Cell Death Caused by Cellular Cholesterol Accumulation.

PubMed

Funakoshi, Takeshi; Aki, Toshihiko; Tajiri, Masateru; Unuma, Kana; Uemura, Koichi

2016-11-25

Aberrant cellular accumulation of cholesterol is associated with neuronal lysosomal storage disorders such as Niemann-Pick disease Type C (NPC). We have shown previously that l-norephedrine (l-Nor), a sympathomimetic amine, induces necrotic cell death associated with massive cytoplasmic vacuolation in SH-SY5Y human neuroblastoma cells. To reveal the molecular mechanism underling necrotic neuronal cell death caused by l-Nor, we examined alterations in the gene expression profile of cells during l-Nor exposure. DNA microarray analysis revealed that the gene levels for cholesterol transport (LDL receptor and NPC2) as well as cholesterol biosynthesis (mevalonate pathway enzymes) are increased after exposure to 3 mm l-Nor for ∼6 h. Concomitant with this observation, the master transcriptional regulator of cholesterol homeostasis, SREBP-2, is activated by l-Nor. The increase in cholesterol uptake as well as biosynthesis is not accompanied by an increase in cholesterol in the plasma membrane, but rather by aberrant accumulation in cytoplasmic compartments. We also found that cell death by l-Nor can be suppressed by nec-1s, an inhibitor of a regulated form of necrosis, necroptosis. Abrogation of SREBP-2 activation by the small molecule inhibitor betulin or by overexpression of dominant-negative SREBP-2 efficiently reduces cell death by l-Nor. The mobilization of cellular cholesterol in the presence of cyclodextrin also suppresses cell death. These results were also observed in primary culture of striatum neurons. Taken together, our results indicate that the excessive uptake as well as synthesis of cholesterol should underlie neuronal cell death by l-Nor exposure, and suggest a possible link between lysosomal cholesterol storage disorders and the regulated form of necrosis in neuronal cells. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Necroptosis-like Neuronal Cell Death Caused by Cellular Cholesterol Accumulation*

PubMed Central

Funakoshi, Takeshi; Aki, Toshihiko; Tajiri, Masateru; Unuma, Kana; Uemura, Koichi

2016-01-01

Aberrant cellular accumulation of cholesterol is associated with neuronal lysosomal storage disorders such as Niemann-Pick disease Type C (NPC). We have shown previously that l-norephedrine (l-Nor), a sympathomimetic amine, induces necrotic cell death associated with massive cytoplasmic vacuolation in SH-SY5Y human neuroblastoma cells. To reveal the molecular mechanism underling necrotic neuronal cell death caused by l-Nor, we examined alterations in the gene expression profile of cells during l-Nor exposure. DNA microarray analysis revealed that the gene levels for cholesterol transport (LDL receptor and NPC2) as well as cholesterol biosynthesis (mevalonate pathway enzymes) are increased after exposure to 3 mm l-Nor for ∼6 h. Concomitant with this observation, the master transcriptional regulator of cholesterol homeostasis, SREBP-2, is activated by l-Nor. The increase in cholesterol uptake as well as biosynthesis is not accompanied by an increase in cholesterol in the plasma membrane, but rather by aberrant accumulation in cytoplasmic compartments. We also found that cell death by l-Nor can be suppressed by nec-1s, an inhibitor of a regulated form of necrosis, necroptosis. Abrogation of SREBP-2 activation by the small molecule inhibitor betulin or by overexpression of dominant-negative SREBP-2 efficiently reduces cell death by l-Nor. The mobilization of cellular cholesterol in the presence of cyclodextrin also suppresses cell death. These results were also observed in primary culture of striatum neurons. Taken together, our results indicate that the excessive uptake as well as synthesis of cholesterol should underlie neuronal cell death by l-Nor exposure, and suggest a possible link between lysosomal cholesterol storage disorders and the regulated form of necrosis in neuronal cells. PMID:27756839

Sodium valproate, a histone deacetylase inhibitor, modulates the vascular endothelial growth inhibitor-mediated cell death in human osteosarcoma and vascular endothelial cells.

PubMed

Yamanegi, Koji; Kawabe, Mutsuki; Futani, Hiroyuki; Nishiura, Hiroshi; Yamada, Naoko; Kato-Kogoe, Nahoko; Kishimoto, Hiromitsu; Yoshiya, Shinichi; Nakasho, Keiji

2015-05-01

The level of vascular endothelial growth inhibitor (VEGI) has been reported to be negatively associated with neovascularization in malignant tumors. The soluble form of VEGI is a potent anti-angiogenic factor due to its effects in inhibiting endothelial cell proliferation. This inhibition is mediated by death receptor 3 (DR3), which contains a death domain in its cytoplasmic tail capable of inducing apoptosis that can be subsequently blocked by decoy receptor 3 (DcR3). We investigated the effects of sodium valproate (VPA) and trichostatin A (TSA), histone deacetylase inhibitors, on the expression of VEGI and its related receptors in human osteosarcoma (OS) cell lines and human microvascular endothelial (HMVE) cells. Consequently, treatment with VPA and TSA increased the VEGI and DR3 expression levels without inducing DcR3 production in the OS cell lines. In contrast, the effect on the HMVE cells was limited, with no evidence of growth inhibition or an increase in the DR3 and DcR3 expression. However, VPA-induced soluble VEGI in the OS cell culture medium markedly inhibited the vascular tube formation of HMVE cells, while VEGI overexpression resulted in enhanced OS cell death. Taken together, the HDAC inhibitor has anti-angiogenesis and antitumor activities that mediate soluble VEGI/DR3-induced apoptosis via both autocrine and paracrine pathways. This study indicates that the HDAC inhibitor may be exploited as a therapeutic strategy modulating the soluble VEGI/DR3 pathway in osteosarcoma patients.

Muscarinic Receptor Activation Protects Cells from Apoptotic Effects of DNA Damage, Oxidative Stress, and Mitochondrial Inhibition*

PubMed Central

De Sarno, Patrizia; Shestopal, Svetlana A.; King, Taj D.; Zmijewska, Anna; Song, Ling; Jope, Richard S.

2006-01-01

The impact of muscarinic receptor stimulation was examined on apoptotic signaling induced by DNA damage, oxidative stress, and mitochondrial impairment. Exposure of human neuroblastoma SH-SY5Y cells to the DNA-damaging agent camptothecin increased p53 levels, activated caspase-3, and caused cell death. Pretreatment with oxotremorine-M, a selective agonist of muscarinic receptors that are expressed endogenously in these cells, did not affect the accumulation of p53 but greatly attenuated caspase-3 activation and protected from cell death to nearly the same extent as treatment with a general caspase inhibitor. Treatment with 50–200 μm H2O2 caused the activation of caspase-3 beginning after 2–3 h, followed by eventual cell death. Oxotremorine-M pretreatment protected cells from H2O2-inducedcaspase-3 activation and death, and this was equivalent to protection afforded by a caspase inhibitor. Muscarinic receptor stimulation also protected cells from caspase-3 activation induced by exposure to rotenone, a mitochondrial complex 1 inhibitor, but no protection was evident from staurosporine-induced caspase-3 activation. The mechanism of protection afforded by muscarinic receptor activation from camptothecin-induced apoptotic signaling involved blockade of mitochondrial cytochrome c release associated with a bolstering of mitochondrial bcl-2 levels and blockade of the translocation of Bax to mitochondria. Likely the most proximal of these events to muscarinic receptor activation, mitochondrial Bax accumulation, also was attenuated by oxotremorine-M treatment after treatment with H2O2 or rotenone. These results demonstrate that stimulation of muscarinic receptors provides substantial protection from DNA damage, oxidative stress, and mitochondrial impairment, insults that may be encountered by neurons in development, aging, or neurodegenerative diseases. These findings suggest that neurotransmitter-induced signaling bolsters survival mechanisms, and inadequate

Macrophage-mediated trogocytosis leads to death of antibody-opsonized tumor cells

PubMed Central

Velmurugan, Ramraj; Challa, Dilip K.; Ram, Sripad; Ober, Raimund J.; Ward, E. Sally

2016-01-01

Understanding the complex behavior of effector cells such as monocytes or macrophages in regulating cancerous growth is of central importance for cancer immunotherapy. Earlier studies using CD20-specific antibodies have demonstrated that the Fcγ receptor (FcγR)-mediated transfer of the targeted receptors from tumor cells to these effector cells through trogocytosis can enable escape from antibody therapy, leading to the viewpoint that this process is pro-tumorigenic. In the current study we demonstrate that persistent trogocytic attack results in the killing of HER2-overexpressing breast cancer cells. Further, antibody engineering to increase FcγR interactions enhances this tumoricidal activity. These studies extend the complex repertoire of activities of macrophages to trogocytic-mediated cell death of HER2-overexpressing target cells and have implications for the development of effective antibody-based therapies. PMID:27226489

Post-Transcriptional Control of Angiotensin II Type 1 Receptor Regulates Osteosarcoma Cell Death.

PubMed

Zhao, Yue; Xu, Kaicheng; Liu, Peng

2018-01-01

MicroRNAs (miRNAs) play an essential role in the tumorigenesis of osteosarcoma (OS). However, the effects of miR-1248 on chemo-resistant potential of OS have not been studied. Here, we addressed this question. The levels of miR-1248 and apoptotic protein angiotensin II type 1 receptor (AGTR1) in OS specimens were examined by RT-qPCR and Western blotting, respectively. The relationship between miR-1248 and AGTR1 was determined by analysis of Spearman's Rank Correlation Coefficients. The patient survival was determined with Kaplan-Meier curves. Bioinformatics analyses were done to predict microRNAs (miRNAs) that target AGTR1. The functional binding of miRNAs to AGTR1 mRNA was examined by a dual luciferase reporter assay. Cell viability was determined by an CCK-8 assay. Apoptosis was determined by a fluorescence-based apoptosis assay. The levels of miR-1248 were significantly elevated while the levels of AGTR1 were significantly decreased in OS specimens than in paired adjacent normal tissue. The levels of miR-1248 were negatively correlated to the levels of AGTR1. Moreover, the patients with high miR-1248 levels had poorer survival than those with low MiR-1248 levels, and the patients with low AGTR1 levels had poorer survival than those with high AGTR1 levels. MiR-1248 inhibited protein translation of AGTR1, through binding to the 3'-UTR of the AGTR1 mRNA. The AGTR1-mediated cell apoptosis was suppressed by overexpressing miR-1248, and was augmented by depleting miR-1248. Increased miR-1248 expression in OS may inhibit AGTR1-mediated cancer cell death in chemotherapy. The outcome of chemotherapy may be improved by the suppression of miR-1248 in OS cells. © 2018 The Author(s). Published by S. Karger AG, Basel.

Angiotensin II potentiates zinc-induced cortical neuronal death by acting on angiotensin II type 2 receptor.

PubMed

Park, Mi-Ha; Kim, Ha Na; Lim, Joon Seo; Ahn, Jae-Sung; Koh, Jae-Young

2013-12-01

The angiotensin system has several non-vascular functions in the central nervous system. For instance, inhibition of the brain angiotensin system results in a reduction in neuronal death following acute brain injury such as ischemia and intracerebral hemorrhage, even under conditions of constant blood pressure. Since endogenous zinc has been implicated as a key mediator of ischemic neuronal death, we investigated the possibility that the angiotensin system affects the outcome of zinc-triggered neuronal death in cortical cell cultures. Exposure of cortical cultures containing neurons and astrocytes to 300 μM zinc for 15 min induced submaximal death in both types of cells. Interestingly, addition of angiotensin II significantly enhanced the zinc-triggered neuronal death, while leaving astrocytic cell death relatively unchanged. Both type 1 and 2 angiotensin II receptors (AT1R and AT2R, respectively) were expressed in neurons as well as astrocytes. Zinc neurotoxicity was substantially attenuated by PD123319, a specific inhibitor of AT2R, and augmented by CGP42112, a selective activator of AT2R, indicating a critical role for this receptor subtype in the augmentation of neuronal cell death.Because zinc toxicity occurs largely through oxidative stress, the levels of superoxides in zinc-treated neurons were assessed by DCF fluorescence microscopy. Combined treatment with zinc and angiotensin II substantially increased the levels of superoxides in neurons compared to those induced by zinc alone. This increase in oxidative stress by angiotensin II was completely blocked by the addition of PD123319. Finally, since zinc-induced oxidative stress may be caused by induction and/or activation of NADPH oxidase, the activation status of Rac and the level of the NADPH oxidase subunit p67phox were measured. Angiotensin II markedly increased Rac activity and the levels of p67phox in zinc-treated neurons and astrocytes in a PD123319-dependent manner. The present study shows that the

Knockdown of estrogen receptor-α induces autophagy and inhibits antiestrogen-mediated unfolded protein response activation, promoting ROS-induced breast cancer cell death

PubMed Central

Cook, Katherine L.; Clarke, Pamela A. G.; Parmar, Jignesh; Hu, Rong; Schwartz-Roberts, Jessica L.; Abu-Asab, Mones; Wärri, Anni; Baumann, William T.; Clarke, Robert

2014-01-01

Approximately 70% of all newly diagnosed breast cancers express estrogen receptor (ER)-α. Although inhibiting ER action using targeted therapies such as fulvestrant (ICI) is often effective, later emergence of antiestrogen resistance limits clinical use. We used antiestrogen-sensitive and -resistant cells to determine the effect of antiestrogens/ERα on regulating autophagy and unfolded protein response (UPR) signaling. Knockdown of ERα significantly increased the sensitivity of LCC1 cells (sensitive) and also resensitized LCC9 cells (resistant) to antiestrogen drugs. Interestingly, ERα knockdown, but not ICI, reduced nuclear factor (erythroid-derived 2)-like (NRF)-2 (UPR-induced antioxidant protein) and increased cytosolic kelch-like ECH-associated protein (KEAP)-1 (NRF2 inhibitor), consistent with the observed increase in ROS production. Furthermore, autophagy induction by antiestrogens was prosurvival but did not prevent ERα knockdown–mediated death. We built a novel mathematical model to elucidate the interactions among UPR, autophagy, ER signaling, and ROS regulation of breast cancer cell survival. The experimentally validated mathematical model explains the counterintuitive result that knocking down the main target of ICI (ERα) increased the effectiveness of ICI. Specifically, the model indicated that ERα is no longer present in excess and that the effect on proliferation from further reductions in its level by ICI cannot be compensated for by increased autophagy. The stimulation of signaling that can confer resistance suggests that combining autophagy or UPR inhibitors with antiestrogens would reduce the development of resistance in some breast cancers.—Cook, K. L., Clarke, P. A. G., Parmar, J., Hu, R., Schwartz-Roberts, J. L., Abu-Asab, M., Wärri, A., Baumann, W. T., Clarke, R. Knockdown of estrogen receptor-α induces autophagy and inhibits antiestrogen-mediated unfolded protein response activation, promoting ROS-induced breast cancer cell death

Depletion of the Receptor-Interacting Protein Kinase 3 (RIP3) Decreases Photoreceptor Cell Death During the Early Stages of Ocular Murine Cytomegalovirus Infection.

PubMed

Xu, Jinxian; Mo, Juan; Liu, Xinglou; Marshall, Brendan; Atherton, Sally S; Dong, Zheng; Smith, Sylvia; Zhang, Ming

2018-05-01

The purpose of this study was to determine if the receptor-interacting protein kinase 3 (RIP3) plays a significant role in innate immune responses and death of bystander retinal neurons during murine cytomegalovirus (MCMV) retinal infection, by comparing the innate immune response and cell death in RIP3-depleted mice (Rip3-/-) and Rip3+/+ control mice. Rip3-/- and Rip3+/+ mice were immunosuppressed (IS) and inoculated with MCMV via the supraciliary route. Virus-injected and mock-injected control eyes were removed at days 4, 7, and 10 post infection (p.i.) and markers of innate immunity and cell death were analyzed. Compared to Rip3+/+ mice, significantly more MCMV was recovered and more MCMV-infected RPE cells were observed in injected eyes of Rip3-/- mice at days 4 and 7 p.i. In contrast, fewer TUNEL-stained photoreceptors were observed in Rip3-/- eyes than in Rip3+/+ eyes at these times. Electron microscopy showed that significantly more apoptotic photoreceptor cells were present in Rip3+/+ mice than in Rip3-/- mice. Immunohistochemistry showed that the majority of TUNEL-stained photoreceptors died via mitochondrial flavoprotein apoptosis-inducing factor (AIF)-mediated, caspase 3-independent apoptosis. The majority of RIP3-expressing cells in infected eyes were RPE cells, microglia/macrophages, and glia, whereas retinal neurons contained much lower amounts of RIP3. Western blots showed significantly higher levels of activated nuclear factor-κB and caspase 1 were present in Rip3+/+ eyes compared to Rip3-/- eyes. Our results suggest that RIP3 enhances innate immune responses against ocular MCMV infection via activation of the inflammasome and nuclear factor-κB, which also leads to inflammation and death of bystander cells by multiple pathways including apoptosis and necroptosis.

Depletion of the Receptor-Interacting Protein Kinase 3 (RIP3) Decreases Photoreceptor Cell Death During the Early Stages of Ocular Murine Cytomegalovirus Infection

PubMed Central

Xu, Jinxian; Mo, Juan; Liu, Xinglou; Marshall, Brendan; Atherton, Sally S.; Dong, Zheng; Smith, Sylvia

2018-01-01

Purpose The purpose of this study was to determine if the receptor-interacting protein kinase 3 (RIP3) plays a significant role in innate immune responses and death of bystander retinal neurons during murine cytomegalovirus (MCMV) retinal infection, by comparing the innate immune response and cell death in RIP3-depleted mice (Rip3−/−) and Rip3+/+ control mice. Methods Rip3−/− and Rip3+/+ mice were immunosuppressed (IS) and inoculated with MCMV via the supraciliary route. Virus-injected and mock-injected control eyes were removed at days 4, 7, and 10 post infection (p.i.) and markers of innate immunity and cell death were analyzed. Results Compared to Rip3+/+ mice, significantly more MCMV was recovered and more MCMV-infected RPE cells were observed in injected eyes of Rip3−/− mice at days 4 and 7 p.i. In contrast, fewer TUNEL-stained photoreceptors were observed in Rip3−/− eyes than in Rip3+/+ eyes at these times. Electron microscopy showed that significantly more apoptotic photoreceptor cells were present in Rip3+/+ mice than in Rip3−/− mice. Immunohistochemistry showed that the majority of TUNEL-stained photoreceptors died via mitochondrial flavoprotein apoptosis-inducing factor (AIF)-mediated, caspase 3–independent apoptosis. The majority of RIP3-expressing cells in infected eyes were RPE cells, microglia/macrophages, and glia, whereas retinal neurons contained much lower amounts of RIP3. Western blots showed significantly higher levels of activated nuclear factor–κB and caspase 1 were present in Rip3+/+ eyes compared to Rip3−/− eyes. Conclusions Our results suggest that RIP3 enhances innate immune responses against ocular MCMV infection via activation of the inflammasome and nuclear factor–κB, which also leads to inflammation and death of bystander cells by multiple pathways including apoptosis and necroptosis.

Role and regulation of apoptotic cell death in the kidney. Y2K update.

PubMed

Ortiz, A; Lorz, C; Catalan, M P; Justo, P; Egido, J

2000-08-01

Apoptosis is an active form of cell death that, in balance with mitosis, regulates cell number. Cell number abnormalities are a frequent feature of renal disease. We now review current concepts on the molecular regulation of apoptotic cell death, including the influence of survival and lethal factors from the extracellular microenvironment as well as the role of intracellular regulators of apoptosis, such as death receptors, proapoptotic and antiapoptotic bcl2-related proteins, the mitochondria and caspases. In addition the role of apoptosis in the genesis, persistence and progression and remodeling and resolution of renal injury is discussed. Information on the expression and function of apoptosis regulatory proteins in specific renal syndromes is summarized. Finally, future perspectives in research and clinical intervention are discussed.

Colourful death: six-parameter classification of cell death by flow cytometry--dead cells tell tales.

PubMed

Munoz, Luis E; Maueröder, Christian; Chaurio, Ricardo; Berens, Christian; Herrmann, Martin; Janko, Christina

2013-08-01

The response of the immune system against dying and dead cells strongly depends on the cell death phenotype. Beside other forms of cell death, two clearly distinct populations, early apoptotic and secondary necrotic cells, have been shown to induce anti-inflammation/tolerance and inflammation/immune priming, respectively. Cytofluorometry is a powerful technique to detect morphological and phenotypical changes occurring during cell death. Here, we describe a new technique using AnnexinA5, propidiumiodide, DiIC1(5) and Hoechst 33342 to sub-classify populations of apoptotic and/or necrotic cells. The method allows the fast and reliable identification of several different phases and pathways of cell death by analysing the following cell death associated changes in a single tube: cellular granularity and shrinkage, phosphatidylserine exposure, ion selectivity of the plasma membrane, mitochondrial membrane potential, and DNA content. The clear characterisation of cell death is of major importance for instance in immunization studies, in experimental therapeutic settings, and in the exploration of cell-death associated diseases. It also enables the analysis of immunological properties of distinct populations of dying cells and the pathways involved in this process.

Calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors trigger neuronal nitric-oxide synthase activation to promote nerve cell death in an Src kinase-dependent fashion.

PubMed

Socodato, Renato; Santiago, Felipe N; Portugal, Camila C; Domingues, Ana F; Santiago, Ana R; Relvas, João B; Ambrósio, António F; Paes-de-Carvalho, Roberto

2012-11-09

In the retina information decoding is dependent on excitatory neurotransmission and is critically modulated by AMPA glutamate receptors. The Src-tyrosine kinase has been implicated in modulating neurotransmission in CNS. Thus, our main goal was to correlate AMPA-mediated excitatory neurotransmission with the modulation of Src activity in retinal neurons. Cultured retinal cells were used to access the effects of AMPA stimulation on nitric oxide (NO) production and Src phosphorylation. 4-Amino-5-methylamino-2',7'-difluorofluorescein diacetate fluorescence mainly determined NO production, and immunocytochemistry and Western blotting evaluated Src activation. AMPA receptors activation rapidly up-regulated Src phosphorylation at tyrosine 416 (stimulatory site) and down-regulated phosphotyrosine 527 (inhibitory site) in retinal cells, an effect mainly mediated by calcium-permeable AMPA receptors. Interestingly, experiments confirmed that neuronal NOS was activated in response to calcium-permeable AMPA receptor stimulation. Moreover, data suggest NO pathway as a key regulatory signaling in AMPA-induced Src activation in neurons but not in glial cells. The NO donor SNAP (S-nitroso-N-acetyl-DL-penicillamine) and a soluble guanylyl cyclase agonist (YC-1) mimicked AMPA effect in Src Tyr-416 phosphorylation, reinforcing that Src activation is indeed modulated by the NO pathway. Gain and loss-of-function data demonstrated that ERK is a downstream target of AMPA-induced Src activation and NO signaling. Furthermore, AMPA stimulated NO production in organotypic retinal cultures and increased Src activity in the in vivo retina. Additionally, AMPA-induced apoptotic retinal cell death was regulated by both NOS and Src activity. Because Src activity is pivotal in several CNS regions, the data presented herein highlight that Src modulation is a critical step in excitatory retinal cell death.

The Relationship Between the Renin-Angiotensin-Aldosterone System and NMDA Receptor-Mediated Signal and the Prevention of Retinal Ganglion Cell Death.

PubMed

Kobayashi, Mamoru; Hirooka, Kazuyuki; Ono, Aoi; Nakano, Yuki; Nishiyama, Akira; Tsujikawa, Akitaka

2017-03-01

Excitotoxicity, which is due to glutamate-induced toxic effects on the retinal ganglion cell (RGC), is one of several mechanisms of RGC loss. The renin-angiotensin-aldosterone system (RAAS) has also been implicated in RGC death. Therefore, it is important to determine the exact relationship between the RAAS and N-methyl-d-aspartate (NMDA) receptor-mediated signal in order to prevent RGC death. N-methyl-d-aspartate or aldosterone was injected into the vitreous body. After intravitreal injection of NMDA or aldosterone, animals were treated with spironolactone or memantine. Retinal damage was evaluated by measuring the number of RGCs at 4 weeks after local administration of aldosterone or at 2 weeks after local administration of NMDA. Vitreous humor levels of aldosterone were measured using enzyme immunoassay kits. A significantly decreased number of RGCs were observed after intravitreal injection of NMDA. Although spironolactone did not show any neuroprotective effects, memantine significantly reduced NMDA-induced degeneration in the retina. Furthermore, a significant decrease in the number of RGCs was observed after an intravitreal injection of aldosterone. While memantine did not exhibit any neuroprotective effects, spironolactone caused a significant reduction in the aldosterone-induced degeneration in the retina. There was no change in the aldosterone concentration in the vitreous humor after an NMDA injection. Our findings indirectly show that there is no relationship between the RAAS and NMDA receptor-mediated signal with regard to RGC death.

Carvedilol protects bone marrow stem cells against hydrogen peroxide-induced cell death via PI3K-AKT pathway.

PubMed

Chen, Meihui; Chen, Shudong; Lin, Dingkun

2016-03-01

Carvedilol, a nonselective β-adrenergic receptor blocker, has been reported to exert potent anti-oxidative activities. In the present study, we aimed to investigate the effects of carvedilol against hydrogen peroxide (H2O2)-induced bone marrow-derived mesenchymal stem cells (BMSCs) death, which imitate the microenvironment surrounding transplanted cells in the injured spinal cord in vitro. Carvedilol significantly reduced H2O2-induced reactive oxygen species production, apoptosis and subsequent cell death. LY294002, the PI3K inhibitor, blocked the protective effects and up-regulation of Akt phosphorylation of carvedilol. Together, our results showed that carvedilol protects H2O2-induced BMSCs cell death partly through PI3K-Akt pathway, suggesting carvedilol could be used in combination with BMSCs for the treatment of spinal cord injury by improving the cell survival and oxidative stress microenvironments. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

RIPK1/RIPK3/MLKL-mediated necroptosis contributes to compression-induced rat nucleus pulposus cells death.

PubMed

Chen, Songfeng; Lv, Xiao; Hu, Binwu; Shao, Zengwu; Wang, Baichuan; Ma, Kaige; Lin, Hui; Cui, Min

2017-05-01

The aim of this study was to systematically investigate the role of necroptosis in compression-induced rat nucleus pulposus (NP) cells death, as well as explore the underlying mechanisms involved. Rat NP cells underwent various periods of exposure to 1.0 MPa pressure. Cell viability and cell death were quantified by using cell counting kit-8 (CCK-8), and Calcein-AM/propidium iodine (PI) staining respectively. Necroptosis-associated target molecules receptor-interacing protein kinase 1 (RIPK1), phosphorylated RIPK1 (pRIPK1), receptor-interacing protein kinase 3 (RIPK3), phosphorylated RIPK3 (pRIPK3) and mixed lineage kinase domain-like (MLKL) were analyzed by Western-blot and RT-PCR. NP cells were also examined for morphological and ultrastructural changes, which can indicate necroptosis. To indirectly establish the presence of necroptosis, the RIPK1 specific inhibitor necrostatin-1 (Nec-1), RIPK3 inhibitor GSK'872, MLKL inhibitor necrosulfonamide (NSA) and small interfering RNA (siRNA) were utilized. The results established necroptosis was taking place in NP cells. The level of necroptosis increased in a time-dependent manner, and this effect was reduced by Nec-1 in vitro. Additionally, NP cells death were significantly attenuated following treatment with Nec-1, GSK'872 or NSA. SiRNA-induced knockdown of RIPK3 or MLKL increased cell survival rate, while knockdown of RIPK1 resulted in a decreased cell survival rate. In summary, RIPK1/RIPK3/MLKL-mediated necroptosis may play an important role in NP cells death induced by continuous mechanical stress. Treatment strategies which aim to regulate necroptosis may prove beneficial, by both reducing NP cells death and slowing IVD degeneration.

Cytosolic activation of cell death and stem rust resistance by cereal MLA-family CC-NLR proteins.

PubMed

Cesari, Stella; Moore, John; Chen, Chunhong; Webb, Daryl; Periyannan, Sambasivam; Mago, Rohit; Bernoux, Maud; Lagudah, Evans S; Dodds, Peter N

2016-09-06

Plants possess intracellular immune receptors designated "nucleotide-binding domain and leucine-rich repeat" (NLR) proteins that translate pathogen-specific recognition into disease-resistance signaling. The wheat immune receptors Sr33 and Sr50 belong to the class of coiled-coil (CC) NLRs. They confer resistance against a broad spectrum of field isolates of Puccinia graminis f. sp. tritici, including the Ug99 lineage, and are homologs of the barley powdery mildew-resistance protein MLA10. Here, we show that, similarly to MLA10, the Sr33 and Sr50 CC domains are sufficient to induce cell death in Nicotiana benthamiana Autoactive CC domains and full-length Sr33 and Sr50 proteins self-associate in planta In contrast, truncated CC domains equivalent in size to an MLA10 fragment for which a crystal structure was previously determined fail to induce cell death and do not self-associate. Mutations in the truncated region also abolish self-association and cell-death signaling. Analysis of Sr33 and Sr50 CC domains fused to YFP and either nuclear localization or nuclear export signals in N benthamiana showed that cell-death induction occurs in the cytosol. In stable transgenic wheat plants, full-length Sr33 proteins targeted to the cytosol provided rust resistance, whereas nuclear-targeted Sr33 was not functional. These data are consistent with CC-mediated induction of both cell-death signaling and stem rust resistance in the cytosolic compartment, whereas previous research had suggested that MLA10-mediated cell-death and disease resistance signaling occur independently, in the cytosol and nucleus, respectively.

Cell Death in C. elegans Development.

PubMed

Malin, Jennifer Zuckerman; Shaham, Shai

2015-01-01

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

Function of endoplasmic reticulum calcium ATPase in innate immunity-mediated programmed cell death

PubMed Central

Zhu, Xiaohong; Caplan, Jeffrey; Mamillapalli, Padmavathi; Czymmek, Kirk; Dinesh-Kumar, Savithramma P

2010-01-01

Programmed cell death (PCD) initiated at the pathogen-infected sites during the plant innate immune response is thought to prevent the development of disease. Here, we describe the identification and characterization of an ER-localized type IIB Ca2+-ATPase (NbCA1) that function as a regulator of PCD. Silencing of NbCA1 accelerates viral immune receptor N- and fungal-immune receptor Cf9-mediated PCD, as well as non-host pathogen Pseudomonas syringae pv. tomato DC3000 and the general elicitor cryptogein-induced cell death. The accelerated PCD rescues loss-of-resistance phenotype of Rar1, HSP90-silenced plants, but not SGT1-silenced plants. Using a genetically encoded calcium sensor, we show that downregulation of NbCA1 results in the modulation of intracellular calcium signalling in response to cryptogein elicitor. We further show that NbCAM1 and NbrbohB function as downstream calcium decoders in N-immune receptor-mediated PCD. Our results indicate that ER-Ca2+-ATPase is a component of the calcium efflux pathway that controls PCD during an innate immune response. PMID:20075858

Effects of intracellular iron overload on cell death and identification of potent cell death inhibitors.

PubMed

Fang, Shenglin; Yu, Xiaonan; Ding, Haoxuan; Han, Jianan; Feng, Jie

2018-06-11

Iron overload causes many diseases, while the underlying etiologies of these diseases are unclear. Cell death processes including apoptosis, necroptosis, cyclophilin D-(CypD)-dependent necrosis and a recently described additional form of regulated cell death called ferroptosis, are dependent on iron or iron-dependent reactive oxygen species (ROS). However, whether the accumulation of intracellular iron itself induces ferroptosis or other forms of cell death is largely elusive. In present study, we study the role of intracellular iron overload itself-induced cell death mechanisms by using ferric ammonium citrate (FAC) and a membrane-permeable Ferric 8-hydroxyquinoline complex (Fe-8HQ) respectively. We show that FAC-induced intracellular iron overload causes ferroptosis. We also identify 3-phosphoinositide-dependent kinase 1 (PDK1) inhibitor GSK2334470 as a potent ferroptosis inhibitor. Whereas, Fe-8HQ-induced intracellular iron overload causes unregulated necrosis, but partially activates PARP-1 dependent parthanatos. Interestingly, we identify many phenolic compounds as potent inhibitors of Fe-8HQ-induced cell death. In conclusion, intracellular iron overload-induced cell death form might be dependent on the intracellular iron accumulation rate, newly identified cell death inhibitors in our study that target ferroptosis and unregulated oxidative cell death represent potential therapeutic strategies against iron overload related diseases. Copyright © 2018 Elsevier Inc. All rights reserved.

Oxidative stress activates the TRPM2-Ca2+-CaMKII-ROS signaling loop to induce cell death in cancer cells.

PubMed

Wang, Qian; Huang, Lihong; Yue, Jianbo

2017-06-01

High intracellular levels of reactive oxygen species (ROS) cause oxidative stress that results in numerous pathologies, including cell death. Transient potential receptor melastatin-2 (TRPM2), a Ca 2+ -permeable cation channel, is mainly activated by intracellular adenosine diphosphate ribose (ADPR) in response to oxidative stress. Here we studied the role and mechanisms of TRPM2-mediated Ca 2+ influx on oxidative stress-induced cell death in cancer cells. We found that oxidative stress activated the TRPM2-Ca 2+ -CaMKII cascade to inhibit early autophagy induction, which ultimately led to cell death in TRPM2 expressing cancer cells. On the other hand, TRPM2 knockdown switched cells from cell death to autophagy for survival in response to oxidative stress. Moreover, we found that oxidative stress activated the TRPM2-CaMKII cascade to further induce intracellular ROS production, which led to mitochondria fragmentation and loss of mitochondrial membrane potential. In summary, our data demonstrated that oxidative stress activates the TRPM2-Ca 2+ -CaMKII-ROS signal loop to inhibit autophagy and induce cell death. Copyright © 2016 Elsevier B.V. All rights reserved.

What cell death does in development.

PubMed

Zakeri, Zahra; Penaloza, Carlos G; Smith, Kyle; Ye, Yixia; Lockshin, Richard A

2015-01-01

Cell death is prominent in gametogenesis and shapes and sculpts embryos. In non-mammalian embryos one sees little or no cell death prior to the maternal-zygotic transition, but, in mammalian embryos, characteristic deaths of one or two cells occur at the end of compaction and are apparently necessary for the separation of the trophoblast from the inner cell mass. Considerable sculpting of the embryo occurs by cell deaths during organogenesis, and appropriate cell numbers, especially in the CNS and in the immune system, are generated by massive overproduction of cells and selection of a few, with death of the rest. The timing, identity, and genetic control of specific cells that die have been well documented in Caenorhabditis, but in other embryos the stochastic nature of the deaths limit our ability to do more than identify the regions in which cells will die. Complete disruption of the cell death machinery can be lethal, but many mutations of the regulatory machinery yield only modest or no phenotypes, indicating substantial redundancy and compensation of regulatory mechanisms. Most of the deaths are apoptotic and are identified by techniques used to recognize apoptosis, but techniques identifying lysosomes (whether in dying or involuting cells or in the phagocytes that invade the tissue) also reveal patterns of cell death. Aberrant cell deaths that produce known phenotypes are typically localized, indicating that the mechanism of activating a programmed death in a specific region, rather than the mechanism of death, is aberrant. These results lead us to conclude that we need to know much more about the conversations among cells that lead cells to commit suicide.

Effect of Gamma Knife Radiosurgery and Programmed Cell Death 1 Receptor Antagonists on Metastatic Melanoma

PubMed Central

Hubbard, Molly; Nordmann, Tyler; Sperduto, Paul W; Clark, H. Brent; Hunt, Matthew A

2017-01-01

Learning objectives To evaluate radiation-induced changes in patients with brain metastasis secondary to malignant melanoma who received treatment with Gamma Knife radiosurgery (GKRS) and programmed cell death 1 (PD-1) receptor antagonists. Introduction  Stereotactic radiosurgery and chemotherapeutics are used together for treatment of metastatic melanoma and have been linked to delayed radiation-induced vasculitic leukoencephalopathy (DRIVL). There have been reports of more intense interactions with new immunotherapeutics targeting PD-1 receptors, but their interactions have not been well described and may result in an accelerated response to GKRS. Here we present data on subjects treated with this combination from a single institution. Methods Records from patients who underwent treatment for metastatic melanoma to the brain with GKRS from 2011 to 2016 were reviewed. Demographics, date of brain metastasis diagnosis, cause of death when applicable, immunotherapeutics, and imaging findings were recorded. The timing of radiation therapy and medications were also documented.  Results A total of 79 subjects were treated with GKRS, and 66 underwent treatment with both GKRS and immunotherapy. Regarding the 30 patients treated with anti-PD-1 immunotherapy, 21 patients received pembrolizumab, seven patients received nivolumab, and two patients received pembrolizumab and nivolumab. Serial imaging was available for interpretation in 25 patients, with 13 subjects who received GKRS and anti-PD-1 immunotherapy less than six weeks of each other. While four subjects had indeterminate/mixed findings on subsequent magnetic resonance imaging (MRI), nine subjects were noted to have progression. Two of these patients showed progression but subsequent imaging revealed a decrease in progression or improvement on MRI to previously targeted lesions by GKRS. None of the 13 subjects had surgery following their combined therapies. Conclusions This data suggests that there is need for

Cytoplasmic PELP1 and ERRgamma Protect Human Mammary Epithelial Cells from Tam-Induced Cell Death

PubMed Central

Girard, Brian J.; Regan Anderson, Tarah M.; Welch, Siya Lem; Nicely, Julie; Seewaldt, Victoria L.; Ostrander, Julie H.

2015-01-01

Tamoxifen (Tam) is the only FDA-approved chemoprevention agent for pre-menopausal women at high risk for developing breast cancer. While Tam reduces a woman's risk of developing estrogen receptor positive (ER+) breast cancer, the molecular mechanisms associated with risk reduction are poorly understood. Prior studies have shown that cytoplasmic proline, glutamic acid and leucine rich protein 1 (PELP1) promotes Tam resistance in breast cancer cell lines. Herein, we tested for PELP1 localization in breast epithelial cells from women at high risk for developing breast cancer and found that PELP1 was localized to the cytoplasm in 36% of samples. In vitro, immortalized HMECs expressing a nuclear localization signal (NLS) mutant of PELP1 (PELP1-cyto) were resistant to Tam-induced death. Furthermore, PELP1-cyto signaling through estrogen-related receptor gamma (ERRγ) promoted cell survival in the presence of Tam. Overexpression of ERRγ in immortalized HMECs protected cells from Tam-induced death, while knockdown of ERRγ sensitized PELP1-cyto expressing HMECs to Tam. Moreover, Tam-induced HMEC cell death was independent of apoptosis and involved accumulation of the autophagy marker LC3-II. Expression of PELP1-cyto and ERRγ reduced Tam-induced LC3-II accumulation, and knockdown of ERRγ increased LC3-II levels in response to Tam. Additionally, PELP1-cyto expression led to the upregulation of MMP-3 and MAOB, known PELP1 and ERRγ target genes, respectively. Our data indicate that cytoplasmic PELP1 induces signaling pathways that converge on ERRγ to promote cell survival in the presence of Tam. These data suggest that PELP1 localization and/or ERRγ activation could be developed as tissue biomarkers for Tam responsiveness. PMID:25789479

Cytoplasmic PELP1 and ERRgamma protect human mammary epithelial cells from Tam-induced cell death.

PubMed

Girard, Brian J; Regan Anderson, Tarah M; Welch, Siya Lem; Nicely, Julie; Seewaldt, Victoria L; Ostrander, Julie H

2015-01-01

Tamoxifen (Tam) is the only FDA-approved chemoprevention agent for pre-menopausal women at high risk for developing breast cancer. While Tam reduces a woman's risk of developing estrogen receptor positive (ER+) breast cancer, the molecular mechanisms associated with risk reduction are poorly understood. Prior studies have shown that cytoplasmic proline, glutamic acid and leucine rich protein 1 (PELP1) promotes Tam resistance in breast cancer cell lines. Herein, we tested for PELP1 localization in breast epithelial cells from women at high risk for developing breast cancer and found that PELP1 was localized to the cytoplasm in 36% of samples. In vitro, immortalized HMECs expressing a nuclear localization signal (NLS) mutant of PELP1 (PELP1-cyto) were resistant to Tam-induced death. Furthermore, PELP1-cyto signaling through estrogen-related receptor gamma (ERRγ) promoted cell survival in the presence of Tam. Overexpression of ERRγ in immortalized HMECs protected cells from Tam-induced death, while knockdown of ERRγ sensitized PELP1-cyto expressing HMECs to Tam. Moreover, Tam-induced HMEC cell death was independent of apoptosis and involved accumulation of the autophagy marker LC3-II. Expression of PELP1-cyto and ERRγ reduced Tam-induced LC3-II accumulation, and knockdown of ERRγ increased LC3-II levels in response to Tam. Additionally, PELP1-cyto expression led to the upregulation of MMP-3 and MAOB, known PELP1 and ERRγ target genes, respectively. Our data indicate that cytoplasmic PELP1 induces signaling pathways that converge on ERRγ to promote cell survival in the presence of Tam. These data suggest that PELP1 localization and/or ERRγ activation could be developed as tissue biomarkers for Tam responsiveness.

Up-regulated Ectonucleotidases in Fas-Associated Death Domain Protein- and Receptor-Interacting Protein Kinase 1-Deficient Jurkat Leukemia Cells Counteract Extracellular ATP/AMP Accumulation via Pannexin-1 Channels during Chemotherapeutic Drug-Induced Apoptosis.

PubMed

Boyd-Tressler, Andrea M; Lane, Graham S; Dubyak, George R

2017-07-01

Pannexin-1 (Panx1) channels mediate the efflux of ATP and AMP from cancer cells in response to induction of extrinsic apoptosis by death receptors or intrinsic apoptosis by chemotherapeutic agents. We previously described the accumulation of extracellular ATP /AMP during chemotherapy-induced apoptosis in Jurkat human leukemia cells. In this study, we compared how different signaling pathways determine extracellular nucleotide pools in control Jurkat cells versus Jurkat lines that lack the Fas-associated death domain (FADD) or receptor-interacting protein kinase 1 (RIP1) cell death regulatory proteins. Tumor necrosis factor- α induced extrinsic apoptosis in control Jurkat cells and necroptosis in FADD-deficient cells; treatment of both lines with chemotherapeutic drugs elicited similar intrinsic apoptosis. Robust extracellular ATP/AMP accumulation was observed in the FADD-deficient cells during necroptosis, but not during apoptotic activation of Panx1 channels. Accumulation of extracellular ATP/AMP was similarly absent in RIP1-deficient Jurkat cells during apoptotic responses to chemotherapeutic agents. Apoptotic activation triggered equivalent proteolytic gating of Panx1 channels in all three Jurkat cell lines. The differences in extracellular ATP/AMP accumulation correlated with cell-line-specific expression of ectonucleotidases that metabolized the released ATP/AMP. CD73 mRNA, and α β -methylene-ADP-inhibitable ecto-AMPase activity were elevated in the FADD-deficient cells. In contrast, the RIP1-deficient cells were defined by increased expression of tartrate-sensitive prostatic acid phosphatase as a broadly acting ectonucleotidase. Thus, extracellular nucleotide accumulation during regulated tumor cell death involves interplay between ATP/AMP efflux pathways and different cell-autonomous ectonucleotidases. Differential expression of particular ectonucleotidases in tumor cell variants will determine whether chemotherapy-induced activation of Panx1 channels

Cardiomyocytes undergo apoptosis in human immunodeficiency virus cardiomyopathy through mitochondrion- and death receptor-controlled pathways

PubMed Central

Twu, Cheryl; Liu, Nancy Q.; Popik, Waldemar; Bukrinsky, Michael; Sayre, James; Roberts, Jaclyn; Rania, Shammas; Bramhandam, Vishnu; Roos, Kenneth P.; MacLellan, W. Robb; Fiala, Milan

2002-01-01

We investigated 18 AIDS hearts (5 with and 13 without cardiomyopathy) by using immunocytochemistry and computerized image analysis regarding the roles of HIV-1 proteins and tumor necrosis factor ligands in HIV cardiomyopathy (HIVCM). HIVCM and cardiomyocyte apoptosis were significantly related to each other and to the expression by inflammatory cells of gp120 and tumor necrosis factor-α. In HIVCM heart, active caspase 9, a component of the mitochondrion-controlled apoptotic pathway, and the elements of the death receptor-mediated pathway, tumor necrosis factor-α and Fas ligand, were expressed strongly on macrophages and weakly on cardiomyocytes. HIVCM showed significantly greater macrophage infiltration and cardiomyocyte apoptosis rate compared with non-HIVCM. HIV-1 entered cultured neonatal rat ventricular myocytes by macropinocytosis but did not replicate. HIV-1- or gp120-induced apoptosis of rat myocytes through a mitochondrion-controlled pathway, which was inhibited by heparin, AOP-RANTES, or pertussis toxin, suggesting that cardiomyocyte apoptosis is induced by signaling through chemokine receptors. In conclusion, in patients with HIVCM, cardiomyocytes die through both mitochondrion- and death receptor-controlled apoptotic pathways. PMID:12379743

Cardiomyocytes undergo apoptosis in human immunodeficiency virus cardiomyopathy through mitochondrion- and death receptor-controlled pathways.

PubMed

Twu, Cheryl; Liu, Nancy Q; Popik, Waldemar; Bukrinsky, Michael; Sayre, James; Roberts, Jaclyn; Rania, Shammas; Bramhandam, Vishnu; Roos, Kenneth P; MacLellan, W Robb; Fiala, Milan

2002-10-29

We investigated 18 AIDS hearts (5 with and 13 without cardiomyopathy) by using immunocytochemistry and computerized image analysis regarding the roles of HIV-1 proteins and tumor necrosis factor ligands in HIV cardiomyopathy (HIVCM). HIVCM and cardiomyocyte apoptosis were significantly related to each other and to the expression by inflammatory cells of gp120 and tumor necrosis factor-alpha. In HIVCM heart, active caspase 9, a component of the mitochondrion-controlled apoptotic pathway, and the elements of the death receptor-mediated pathway, tumor necrosis factor-alpha and Fas ligand, were expressed strongly on macrophages and weakly on cardiomyocytes. HIVCM showed significantly greater macrophage infiltration and cardiomyocyte apoptosis rate compared with non-HIVCM. HIV-1 entered cultured neonatal rat ventricular myocytes by macropinocytosis but did not replicate. HIV-1- or gp120-induced apoptosis of rat myocytes through a mitochondrion-controlled pathway, which was inhibited by heparin, AOP-RANTES, or pertussis toxin, suggesting that cardiomyocyte apoptosis is induced by signaling through chemokine receptors. In conclusion, in patients with HIVCM, cardiomyocytes die through both mitochondrion- and death receptor-controlled apoptotic pathways.

Non-conventional apoptotic response to ionising radiation mediated by N-methyl D-aspartate receptors in immature neuronal cells

PubMed Central

SAMARI, NADA; DE SAINT-GEORGES, LOUIS; PANI, GIUSEPPE; BAATOUT, SARAH; LEYNS, LUC; BENOTMANE, MOHAMMED ABDERRAFI

2013-01-01

During cortical development, N-methyl D-aspartate (NMDA) receptors are highly involved in neuronal maturation and synapse establishment. Their implication in the phenomenon of excitotoxicity has been extensively described in several neurodegenerative diseases due to the permissive entry of Ca2+ ions and massive accumulation in the intracellular compartment, which is highly toxic to cells. Ionising radiation is also a source of stress to the cells, particularly immature neurons. Their capacity to induce cell death has been described for various cell types either by directly damaging the DNA or indirectly through the generation of reactive oxygen species responsible for the activation of a battery of stress response effectors leading in certain cases, to cell death. In this study, in order to determine whether a link exists between NMDA receptors-mediated excitotoxicity and radiation-induced cell death, we evaluated radiation-induced cell death in vitro and in vivo in maturing neurons during the fetal period. Cell death induction was assessed by TUNEL, caspase-3 activity and DNA ladder assays, with or without the administration of dizocilpine (MK-801), a non-competitive NMDA receptor antagonist which blocks neuronal Ca2+ influx. To further investigate the possible involvement of Ca2+-dependent enzyme activation, known to occur at high Ca2+ concentrations, we examined the protective effect of a calpain inhibitor on cell death induced by radiation. Doses ranging from 0.2 to 0.6 Gy of X-rays elicited a clear apoptotic response that was prevented by the injection of dizocilpine (MK-801) or calpain inhibitor. These data demonstrate the involvement of NMDA receptors in radiation-induced neuronal death by the activation of downstream effectors, including calpain-related pathways. An increased apoptotic process elicited by radiation, occurring independently of the normal developmental scheme, may eliminate post-mitotic but immature neuronal cells and deeply impair the

MLKL-PITPα signaling-mediated necroptosis contributes to cisplatin-triggered cell death in lung cancer A549 cells.

PubMed

Jing, Lin; Song, Fei; Liu, Zhenyu; Li, Jianghua; Wu, Bo; Fu, Zhiguang; Jiang, Jianli; Chen, Zhinan

2018-02-01

Necroptosis has been reported to be involved in cisplatin-induced cell death, but the mechanisms underlying the occurrence of necroptosis are not fully elucidated. In this study, we show that apart from apoptosis, cisplatin induces necroptosis in A549 cells. The alleviation of cell death by two necroptosis inhibitors-necrostatin-1 (Nec-1) and necrosulfonamide (NSA), and the phosphorylation of mixed lineage kinase domain-like protein (MLKL) at serine 358, suggest the involvement of receptor-interacting protein kinase 1 (RIPK1)-RIPK3-MLKL signaling in cisplatin-treated A549 cells. Additionally, the initiation of cisplatin-induced necroptosis relies on autocrine tumor necrosis factor alpha (TNF-α). Furthermore, we present the first evidence that phosphatidylinositol transfer protein alpha (PITPα) is involved in MLKL-mediated necroptosis by interacting with the N terminal MLKL on its sixth helix and the preceding loop, which facilitates MLKL oligomerization and plasma membrane translocation in necroptosis. Silencing of PITPα expression interferes with MLKL function and reduces cell death. Our data elucidate that cisplatin-treated lung cancer cells undergo a new type of programmed cell death called necroptosis and shed new light on how MLKL translocates to the plasma membrane. Copyright © 2017 Elsevier B.V. All rights reserved.

Glutathione Efflux and Cell Death

PubMed Central

2012-01-01

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

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. Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Ionotropic and metabotropic glutamate receptor mediation of glucocorticoid-induced apoptosis in hippocampal cells and the neuroprotective role of synaptic N-methyl-D-aspartate receptors.

PubMed

Lu, J; Goula, D; Sousa, N; Almeida, O F X

2003-01-01

Glutamate receptors have been proposed to mediate the apoptotic actions of glucocorticoids in hippocampal cells. To further analyze the role of glutamate receptors in this process, we pretreated primary hippocampal cells from neonatal (postnatal day 4) rats with antagonists of ionotropic glutamate receptor (iGluR) and metabotropic glutamate receptor (mGluR) antagonists before exposure to the specific glucocorticoid receptor agonist dexamethasone (DEX) at a dose of 1 microM. Dizocilpine (MK801; a general N-methyl-D-aspartic acid [NMDA] receptor antagonist, NMDAR antagonist) and ifenprodil (a specific ligand of the NMDAR 2B subunit, NR2B), were used to block iGluR; (RS)-alpha-ethyl-4-carboxyphenylglycine (E4CPG) and (RS)-alpha-cyclopropyl-4-phosphonophenyl-glycine (CPPG) were employed as I/II (E4CPG) and II/III (CPPG) mGluR antagonists. Blockade of iGluR resulted in a significant attenuation of DEX-induced cell death; the finding that ifenprodil exerted a similar potency to MK801 demonstrates the involvement of NR2B receptors in glucocorticoid-induced cell death. Apoptosis accounted for a significant amount of the cell loss observed, as detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling histochemistry for the in situ labeling of DNA breaks; apoptotic cells were distinguished from necrosis on the basis of morphological criteria, including chromatin condensation, membrane blebbing and presence of apoptotic bodies. Treatment with E4CPG and CPPG completely abolished the apoptotic response to DEX, thus showing the additional contribution of mGluR to the phenomenon. Further, dose-response studies with NMDA revealed that whereas high (10 microM) doses of NMDA themselves elicit cytotoxic responses, low (1-5 microM) concentrations of NMDA can effectively oppose DEX-induced cell death. Interestingly, the neuroprotective actions of low dose NMDA stimulation were abolished when either synaptic or extrasynaptic NMDA receptors were blocked with MK801

BH3-Only Molecule Bim Mediates β-Cell Death in IRS2 Deficiency

PubMed Central

Ren, Decheng; Sun, Juan; Mao, Liqun; Ye, Honggang

2014-01-01

Irs2-deficient mice develop type 2–like diabetes due to a reduction in β-cell mass and a failure of pancreatic islets to undergo compensatory hyperplasia in response to insulin resistance. In order to define the molecular mechanisms, we knocked down Irs2 gene expression in mouse MIN6 insulinoma cells. Insulin receptor substrate 2 (IRS2) suppression induced apoptotic cell death, which was associated with an increase in expression of the BH3-only molecule Bim. Knockdown (KD) of Bim reduced apoptotic β-cell death induced by IRS2 suppression. In Irs2-deficient mice, Bim ablation restored β-cell mass, decreased the number of TUNEL-positive cells, and restored normal glucose tolerance after glucose challenge. FoxO1 mediates Bim upregulation induced by IRS2 suppression, and FoxO1 KD partially inhibits β-cell death induced by IRS2 suppression. These results suggest that Bim plays an important role in mediating the increase in β-cell apoptosis and the reduction in β-cell mass that occurs in IRS2-deficient diabetes. PMID:24760140

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

HYAL-2–WWOX–SMAD4 Signaling in Cell Death and Anticancer Response

PubMed Central

Hsu, Li-Jin; Chiang, Ming-Fu; Sze, Chun-I; Su, Wan-Pei; Yap, Ye Vone; Lee, I-Ting; Kuo, Hsiang-Ling; Chang, Nan-Shan

2016-01-01

Hyaluronidase HYAL-2 is a membrane-anchored protein and also localizes, in part, in the lysosome. Recent study from animal models revealed that both HYAL-1 and HYAL-2 are essential for the metabolism of hyaluronan (HA). Hyal-2 deficiency is associated with chronic thrombotic microangiopathy with hemolytic anemia in mice due to over accumulation of high molecular size HA. HYAL-2 is essential for platelet generation. Membrane HYAL-2 degrades HA bound by co-receptor CD44. Also, in a non-canonical signal pathway, HYAL-2 serves as a receptor for transforming growth factor beta (TGF-β) to signal with downstream tumor suppressors WWOX and SMAD4 to control gene transcription. When SMAD4 responsive element is overly driven by the HYAL-2–WWOX–SMAD4 signaling complex, cell death occurs. When rats are subjected to traumatic brain injury, over accumulation of a HYAL-2–WWOX complex occurs in the nucleus to cause neuronal death. HA induces the signaling of HYAL-2–WWOX–SMAD4 and relocation of the signaling complex to the nucleus. If the signaling complex is overexpressed, bubbling cell death occurs in WWOX-expressing cells. In addition, a small synthetic peptide Zfra (zinc finger-like protein that regulates apoptosis) binds membrane HYAL-2 of non-T/non-B spleen HYAL-2+ CD3− CD19− Z lymphocytes and activates the cells to generate memory anticancer response against many types of cancer cells in vivo. Whether the HYAL-2–WWOX–SMAD4 signaling complex is involved is discussed. In this review and opinion article, we have updated the current knowledge of HA, HYAL-2 and WWOX, HYAL-2–WWOX–SMAD4 signaling, bubbling cell death, and Z cell activation for memory anticancer response. PMID:27999774

Calcium-permeable α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptors Trigger Neuronal Nitric-oxide Synthase Activation to Promote Nerve Cell Death in an Src Kinase-dependent Fashion*

PubMed Central

Socodato, Renato; Santiago, Felipe N.; Portugal, Camila C.; Domingues, Ana F.; Santiago, Ana R.; Relvas, João B.; Ambrósio, António F.; Paes-de-Carvalho, Roberto

2012-01-01

In the retina information decoding is dependent on excitatory neurotransmission and is critically modulated by AMPA glutamate receptors. The Src-tyrosine kinase has been implicated in modulating neurotransmission in CNS. Thus, our main goal was to correlate AMPA-mediated excitatory neurotransmission with the modulation of Src activity in retinal neurons. Cultured retinal cells were used to access the effects of AMPA stimulation on nitric oxide (NO) production and Src phosphorylation. 4-Amino-5-methylamino-2′,7′-difluorofluorescein diacetate fluorescence mainly determined NO production, and immunocytochemistry and Western blotting evaluated Src activation. AMPA receptors activation rapidly up-regulated Src phosphorylation at tyrosine 416 (stimulatory site) and down-regulated phosphotyrosine 527 (inhibitory site) in retinal cells, an effect mainly mediated by calcium-permeable AMPA receptors. Interestingly, experiments confirmed that neuronal NOS was activated in response to calcium-permeable AMPA receptor stimulation. Moreover, data suggest NO pathway as a key regulatory signaling in AMPA-induced Src activation in neurons but not in glial cells. The NO donor SNAP (S-nitroso-N-acetyl-dl-penicillamine) and a soluble guanylyl cyclase agonist (YC-1) mimicked AMPA effect in Src Tyr-416 phosphorylation, reinforcing that Src activation is indeed modulated by the NO pathway. Gain and loss-of-function data demonstrated that ERK is a downstream target of AMPA-induced Src activation and NO signaling. Furthermore, AMPA stimulated NO production in organotypic retinal cultures and increased Src activity in the in vivo retina. Additionally, AMPA-induced apoptotic retinal cell death was regulated by both NOS and Src activity. Because Src activity is pivotal in several CNS regions, the data presented herein highlight that Src modulation is a critical step in excitatory retinal cell death. PMID:22992730

Programmed cell death

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

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.

T Cell Calcium Signaling Regulation by the Co-Receptor CD5

PubMed Central

Freitas, Claudia M. Tellez

2018-01-01

Calcium influx is critical for T cell effector function and fate. T cells are activated when T cell receptors (TCRs) engage peptides presented by antigen-presenting cells (APC), causing an increase of intracellular calcium (Ca2+) concentration. Co-receptors stabilize interactions between the TCR and its ligand, the peptide-major histocompatibility complex (pMHC), and enhance Ca2+ signaling and T cell activation. Conversely, some co-receptors can dampen Ca2+ signaling and inhibit T cell activation. Immune checkpoint therapies block inhibitory co-receptors, such as cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) and programmed death 1 (PD-1), to increase T cell Ca2+ signaling and promote T cell survival. Similar to CTLA-4 and PD-1, the co-receptor CD5 has been known to act as a negative regulator of T cell activation and to alter Ca2+ signaling and T cell function. Though much is known about the role of CD5 in B cells, recent research has expanded our understanding of CD5 function in T cells. Here we review these recent findings and discuss how our improved understanding of CD5 Ca2+ signaling regulation could be useful for basic and clinical research. PMID:29701673

GLYCINE-RICH RNA-BINDING PROTEIN1 interacts with RECEPTOR-LIKE CYTOPLASMIC PROTEIN KINASE1 and suppresses cell death and defense responses in pepper (Capsicum annuum).

PubMed

Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

2015-01-01

Plants use a variety of innate immune regulators to trigger cell death and defense responses against pathogen attack. We identified pepper (Capsicum annuum) GLYCINE-RICH RNA-BINDING PROTEIN1 (CaGRP1) as a RECEPTOR-LIKE CYTOPLASMIC PROTEIN KINASE1 (CaPIK1)-interacting partner, based on bimolecular fluorescence complementation and coimmunoprecipitation analyses as well as gene silencing and transient expression analysis. CaGRP1 contains an N-terminal RNA recognition motif and a glycine-rich region at the C-terminus. The CaGRP1 protein had DNA- and RNA-binding activity in vitro. CaGRP1 interacted with CaPIK1 in planta. CaGRP1 and CaGRP1-CaPIK1 complexes were localized to the nucleus in plant cells. CaPIK1 phosphorylated CaGRP1 in vitro and in planta. Transient coexpression of CaGRP1 with CaPIK1 suppressed the CaPIK1-triggered cell death response, accompanied by a reduced CaPIK1-triggered reactive oxygen species (ROS) burst. The RNA recognition motif region of CaGRP1 was responsible for the nuclear localization of CaGRP1 as well as the suppression of the CaPIK1-triggered cell death response. CaGRP1 silencing in pepper conferred enhanced resistance to Xanthomonas campestris pv vesicatoria (Xcv) infection; however, CaPIK1-silenced plants were more susceptible to Xcv. CaGRP1 interacts with CaPIK1 and negatively regulates CaPIK1-triggered cell death and defense responses by suppressing ROS accumulation. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

24(S)-hydroxycholesterol induces neuronal cell death through necroptosis, a form of programmed necrosis.

PubMed

Yamanaka, Kazunori; Saito, Yoshiro; Yamamori, Tohru; Urano, Yasuomi; Noguchi, Noriko

2011-07-15

24(S)-Hydroxycholesterol (24S-OHC) produced by cholesterol 24-hydroxylase expressed mainly in neurons plays an important physiological role in the brain. Conversely, it has been reported that 24S-OHC possesses potent cytotoxicity. The molecular mechanisms of 24S-OHC-induced cell death have not yet been fully elucidated. In this study, using human neuroblastoma SH-SY5Y cells and primary cortical neuronal cells derived from rat embryo, we characterized the form of cell death induced by 24S-OHC. SH-SY5Y cells treated with 24S-OHC exhibited neither fragmentation of the nucleus nor caspase activation, which are the typical characteristics of apoptosis. 24S-OHC-treated cells showed necrosis-like morphological changes but did not induce ATP depletion, one of the features of necrosis. When cells were treated with necrostatin-1, an inhibitor of receptor-interacting serine/threonine kinase 1 (RIPK1) required for necroptosis, 24S-OHC-induced cell death was significantly suppressed. The knockdown of RIPK1 by transfection of small interfering RNA of RIPK1 effectively attenuated 24S-OHC-induced cell death. It was found that neither SH-SY5Y cells nor primary cortical neuronal cells expressed caspase-8, which was regulated for RIPK1-dependent apoptosis. Collectively, these results suggest that 24S-OHC induces neuronal cell death by necroptosis, a form of programmed necrosis.

24(S)-Hydroxycholesterol Induces Neuronal Cell Death through Necroptosis, a Form of Programmed Necrosis*

PubMed Central

Yamanaka, Kazunori; Saito, Yoshiro; Yamamori, Tohru; Urano, Yasuomi; Noguchi, Noriko

2011-01-01

24(S)-Hydroxycholesterol (24S-OHC) produced by cholesterol 24-hydroxylase expressed mainly in neurons plays an important physiological role in the brain. Conversely, it has been reported that 24S-OHC possesses potent cytotoxicity. The molecular mechanisms of 24S-OHC-induced cell death have not yet been fully elucidated. In this study, using human neuroblastoma SH-SY5Y cells and primary cortical neuronal cells derived from rat embryo, we characterized the form of cell death induced by 24S-OHC. SH-SY5Y cells treated with 24S-OHC exhibited neither fragmentation of the nucleus nor caspase activation, which are the typical characteristics of apoptosis. 24S-OHC-treated cells showed necrosis-like morphological changes but did not induce ATP depletion, one of the features of necrosis. When cells were treated with necrostatin-1, an inhibitor of receptor-interacting serine/threonine kinase 1 (RIPK1) required for necroptosis, 24S-OHC-induced cell death was significantly suppressed. The knockdown of RIPK1 by transfection of small interfering RNA of RIPK1 effectively attenuated 24S-OHC-induced cell death. It was found that neither SH-SY5Y cells nor primary cortical neuronal cells expressed caspase-8, which was regulated for RIPK1-dependent apoptosis. Collectively, these results suggest that 24S-OHC induces neuronal cell death by necroptosis, a form of programmed necrosis. PMID:21613228

Antiproliferation and induction of cell death of Phaffia rhodozyma (Xanthophyllomyces dendrorhous) extract fermented by brewer malt waste on breast cancer cells.

PubMed

Teo, Ivy Tuang Ngo; Chui, Chung Hin; Tang, Johnny Cheuk On; Lau, Fung Yi; Cheng, Gregory Yin Ming; Wong, Raymond Siu Ming; Kok, Stanton Hon Lung; Cheng, Chor Hing; Chan, Albert Sun Chi; Ho, Kwok Ping

2005-11-01

Astaxanthin has been shown to have antiproliferative activity on breast cancer and skin cancer cells. However, the high cost of production, isolation and purification of purified astaxanthin from natural sources or chemically synthetic methods limit its usage on cancer therapy. We show that astaxanthin could be produced by fermentating the Phaffia rhodozyma (Xanthophyllomyces dendrorhous) yeast cells with brewer malt waste using a 20 L B. Braun fermentor. The percentage composition of astaxanthin from the P. rhodozyma was >70% of total pigment as estimated by the high performance liquid chromatographic analysis. Furthermore, the antiproliferative activity of this P. rhodozyma cell extract (PRE) was demonstrated on breast cancer cell lines including the MCF-7 (estrogen receptor positive) and MDA-MB231 (estrogen receptor negative) by using the [3-(4,5-dimethylthiazol-2-yl)-5-(3-arboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium] (MTS) assay. No apoptotic cell death, but growth inhibitory effect was induced after 48 h of PRE incubation as suggested by morphological investigation. Anchorage-dependent clonogenicity assay showed that PRE could reduce the colony formation potential of both breast cancer cell lines. Cell death was observed from both breast cancer cell lines after incubation with PRE for 6 days. Taken together, our results showed that by using an economic method of brewer malt waste fermentation, we obtained P. rhodozyma with a high yield of astaxanthin and the corresponding PRE could have short-term growth inhibition and long-term cell death activity on breast cancer cells.

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

PubMed Central

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

2017-01-01

Preeclampsia, a serious hypertensive disorder of pregnancy, is characterized by elevated ceramide (CER) content that is responsible for heightened trophoblast cell death rates via apoptosis and autophagy. Whether trophoblast cells undergo necroptosis, a newly characterized form of regulated necrosis, and the potential role of CER in this process remain to be established. Herein, we report that exposure of both JEG3 cells and primary isolated cytotrophoblasts to C16:0 CER in conjunction with a caspase-8 inhibitor (Q-VD-OPh) promoted necroptotic cell death, as evidenced by increased expression and association of receptor-interacting protein kinases RIP1 and RIP3, as well as phosphorylation of mixed lineage kinase domain-like (MLKL) protein. MLKL activation and oligomerization could be abrogated by pretreatment with the necroptosis inhibitor necrostatin-1 (Nec-1). CER+Q-VD-OPH-treated primary trophoblasts displayed striking necrotic morphology along with disrupted fusion processes as evidenced by maintenance of E-cadherin-stained membrane boundaries and reduced glial cell missing-1 expression, but these events were effectively reversed using Nec-1. Of clinical relevance, we established an increased susceptibility to necroptotic cell death in preeclamptic placentae relative to normotensive controls. In preeclampsia, increased necrosome (RIP1/RIP3) protein levels, as well as MLKL activation and oligomerization associated with necrotic cytotrophoblast morphology. In addition, caspase-8 activity was reduced in severe early-onset preeclampsia cases. This study is the first to report that trophoblast cells undergo CER-induced necroptotic cell death, thereby contributing to the increased placental dysfunction and cell death found in preeclampsia. PMID:28151467

Assembly of oligomeric death domain complexes during Toll receptor signaling.

PubMed

Moncrieffe, Martin C; Grossmann, J Günter; Gay, Nicholas J

2008-11-28

The Drosophila Toll receptor is activated by the endogenous protein ligand Spätzle in response to microbial stimuli in immunity and spatial cues during embryonic development. Downstream signaling is mediated by the adaptor proteins Tube, the kinase Pelle, and the Drosophila homologue of myeloid differentiation primary response protein (dMyD88). Here we have characterized heterodimeric (dMyD88-Tube) and heterotrimeric (dMyD88-Tube-Pelle) death domain complexes. We show that both the heterodimeric and heterotrimeric complexes form kidney-shaped structures and that Tube is bivalent and has separate high affinity binding sites for dMyD88 and Pelle. Additionally we found no interaction between the isolated death domains of Pelle and dMyD88. These results indicate that the mode of assembly of the heterotrimeric dMyD88-Tube-Pelle complex downstream of the activated Toll receptor is unique. The measured dissociation constants for the interaction between the death domains of dMyD88 and Tube and of Pelle and a preformed dMyD88-Tube complex are used to propose a model of the early postreceptor events in Drosophila Toll receptor signaling.

Assembly of Oligomeric Death Domain Complexes during Toll Receptor Signaling*

PubMed Central

Moncrieffe, Martin C.; Grossmann, J. Günter; Gay, Nicholas J.

2008-01-01

The Drosophila Toll receptor is activated by the endogenous protein ligand Spätzle in response to microbial stimuli in immunity and spatial cues during embryonic development. Downstream signaling is mediated by the adaptor proteins Tube, the kinase Pelle, and the Drosophila homologue of myeloid differentiation primary response protein (dMyD88). Here we have characterized heterodimeric (dMyD88-Tube) and heterotrimeric (dMyD88-Tube-Pelle) death domain complexes. We show that both the heterodimeric and heterotrimeric complexes form kidney-shaped structures and that Tube is bivalent and has separate high affinity binding sites for dMyD88 and Pelle. Additionally we found no interaction between the isolated death domains of Pelle and dMyD88. These results indicate that the mode of assembly of the heterotrimeric dMyD88-Tube-Pelle complex downstream of the activated Toll receptor is unique. The measured dissociation constants for the interaction between the death domains of dMyD88 and Tube and of Pelle and a preformed dMyD88-Tube complex are used to propose a model of the early postreceptor events in Drosophila Toll receptor signaling. PMID:18829464

Chronic renal failure induces cell death in rat hippocampal CA1 via upregulation of αCaMKII/NR2A synaptic complex and phosphorylated GluR1-containing AMPA receptor cascades.

PubMed

Kim, Jong Wan; Ha, Gyoung Yim; Jung, Yong Wook

2014-09-01

N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methylisoxazole-4-propinoic acid (AMPA) receptors bound to postsynaptic density-95 (PSD-95) and α isoform of calcium/calmodulin-dependent protein kinase II (αCaMKII) is fundamentally involved in the regulation of working memory. The aim of present study was to investigate the alterations of NMDA and AMPA receptors responsible for hippocampal synaptic dysfunction and selective neuronal cell death after chronic renal failure (CRF) which may be associated with impairment of working memory. Altered interactions between NMDA and AMPA receptors and PSD-95 and αCaMKII were analyzed in the cornu ammonis (CA) 1 and CA3/dentate gyrus (DG) subfields of the uremic rat hippocampi using the immunoblotting and immunoprecipitation methods. Uremia induced by CRF produced necrotic cell death and decreased neuronal nucleoli protein levels in the hippocampal CA1 subfield, but not in the CA3/DG subfields. The CA1 subfields of CRF rats exhibited significant decreases and increases, respectively, in the expressions of PSD-95/NR2B and αCaMKII/NR2A synaptic complex. Moreover, increased phosphorylation of glutamate receptor type 1 (GluR1) AMPA receptor at ser831 was observed in the CA1 subfield after CRF. These hippocampal CA1 neuronal vulnerability may be responsible for memory dysfunction after CRF as mediated by an increase in NR2A-containing NMDA receptors bound to αCaMKII and subsequent activation of GluR1-containing AMPA receptors caused by the phosphorylation of GluR1 at ser831.

The Capsicum annuum class IV chitinase ChitIV interacts with receptor-like cytoplasmic protein kinase PIK1 to accelerate PIK1-triggered cell death and defence responses

PubMed Central

Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

2015-01-01

The pepper receptor-like cytoplasmic protein kinase, CaPIK1, which mediates signalling of plant cell death and defence responses was previously identified. Here, the identification of a class IV chitinase, CaChitIV, from pepper plants (Capsicum annuum), which interacts with CaPIK1 and promotes CaPIK1-triggered cell death and defence responses, is reported. CaChitIV contains a signal peptide, chitin-binding domain, and glycol hydrolase domain. CaChitIV expression was up-regulated by Xanthomonas campestris pv. vesicatoria (Xcv) infection. Notably, avirulent Xcv infection rapidly induced CaChitIV expression in pepper leaves. Bimolecular fluorescence complementation and co-immunoprecipitation revealed that CaPIK1 interacts with CaChitIV in planta, and that the CaPIK1–CaChitIV complex is localized mainly in the cytoplasm and plasma membrane. CaChitIV is also localized in the endoplasmic reticulum. Transient co-expression of CaChitIV with CaPIK1 enhanced CaPIK1-triggered cell death response and reactive oxygen species (ROS) and nitric oxide (NO) bursts. Co-silencing of both CaChitIV and CaPIK1 in pepper plants conferred enhanced susceptibility to Xcv infection, which was accompanied by a reduced induction of cell death response, ROS and NO bursts, and defence response genes. Ectopic expression of CaPIK1 in Arabidopsis enhanced basal resistance to Hyaloperonospora arabidopsidis infection. Together, the results suggest that CaChitIV positively regulates CaPIK1-triggered cell death and defence responses through its interaction with CaPIK1. PMID:25694549

CD47-ligation induced cell death in T-acute lymphoblastic leukemia.

PubMed

Leclair, Pascal; Liu, Chi-Chao; Monajemi, Mahdis; Reid, Gregor S; Sly, Laura M; Lim, Chinten James

2018-05-10

CD47 is a cell-surface marker well recognized for its anti-phagocytic functions. As such, an emerging avenue for targeted cancer therapies involves neutralizing the anti-phagocytic function using monoclonal antibodies (mAbs) to enhance tumour cell immunogenicity. A lesser known consequence of CD47 receptor ligation is the direct induction of tumour cell death. While several mAbs and their derivatives with this property have been studied, the best characterized is the commercially available mAb B6H12, which requires immobilization for induction of cell death. Here, we describe a commercially available mAb, CC2C6, which induces T-cell acute lymphoblastic leukemia (ALL) cell death in soluble form. Soluble CC2C6 induces CD47-dependent cell death in a manner consistent with immobilized B6H12, which is characterized by mitochondrial deficiencies but is independent of caspase activation. Titration studies indicated that CC2C6 shares a common CD47-epitope with B6H12. Importantly, CC2C6 retains the anti-phagocytic neutralizing function, thus possessing dual anti-tumour properties. Although CD47-ligation induced cell death occurs in a caspase-independent manner, CC2C6 was found to stimulate increases in Mcl-1 and NOXA levels, two Bcl-2 family proteins that govern the intrinsic apoptosis pathway. Further analysis revealed that the ratio of Mcl-1:NOXA were minimally altered for cells treated with CC2C6, in comparison to cells treated with agents that induced caspase-dependent apoptosis which alter this ratio in favour of NOXA. Finally, we found that CC2C6 can synergize with low dose chemotherapeutic agents that induce classical apoptosis, giving rise to the possibility of an effective combination treatment with reduced long-term sequelae associated with high-dose chemotherapies in childhood ALL.

Nonthermal-plasma-mediated animal cell death

NASA Astrophysics Data System (ADS)

Kim, Wanil; Woo, Kyung-Chul; Kim, Gyoo-Cheon; Kim, Kyong-Tai

2011-01-01

Animal cell death comprising necrosis and apoptosis occurred in a well-regulated manner upon specific stimuli. The physiological meanings and detailed molecular mechanisms of cell death have been continuously investigated over several decades. Necrotic cell death has typical morphological changes, such as cell swelling and cell lysis followed by DNA degradation, whereas apoptosis shows blebbing formation and regular DNA fragmentation. Cell death is usually adopted to terminate cancer cells in vivo. The current strategies against tumour are based on the induction of cell death by adopting various methods, including radiotherapy and chemotherapeutics. Among these, radiotherapy is the most frequently used treatment method, but it still has obvious limitations. Recent studies have suggested that the use of nonthermal air plasma can be a prominent method for inducing cancer cell death. Plasma-irradiated cells showed the loss of genomic integrity, mitochondrial dysfunction, plasma membrane damage, etc. Tumour elimination with plasma irradiation is an emerging concept in cancer therapy and can be accelerated by targeting certain tumour-specific proteins with gold nanoparticles. Here, some recent developments are described so that the mechanisms related to plasma-mediated cell death and its perspectives in cancer treatment can be understood.

Glutamate Increases In Vitro Survival and Proliferation and Attenuates Oxidative Stress-Induced Cell Death in Adult Spinal Cord-Derived Neural Stem/Progenitor Cells via Non-NMDA Ionotropic Glutamate Receptors.

PubMed

Hachem, Laureen D; Mothe, Andrea J; Tator, Charles H

2016-08-15

Traumatic spinal cord injury (SCI) leads to a cascade of secondary chemical insults, including oxidative stress and glutamate excitotoxicity, which damage host neurons and glia. Transplantation of exogenous neural stem/progenitor cells (NSPCs) has shown promise in enhancing regeneration after SCI, although survival of transplanted cells remains poor. Understanding the response of NSPCs to the chemical mediators of secondary injury is essential in finding therapies to enhance survival. We examined the in vitro effects of glutamate and glutamate receptor agonists on adult rat spinal cord-derived NSPCs. NSPCs isolated from the periventricular region of the adult rat spinal cord were exposed to various concentrations of glutamate for 96 h. We found that glutamate treatment (500 μM) for 96 h significantly increased live cell numbers, reduced cell death, and increased proliferation, but did not significantly alter cell phenotype. Concurrent glutamate treatment (500 μM) in the setting of H2O2 exposure (500 μM) for 10 h increased NSPC survival compared to H2O2 exposure alone. The effects of glutamate on NSPCs were blocked by the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor antagonist GYKI-52466, but not by the N-methyl-D-aspartic acid receptor antagonist MK-801 or DL-AP5, or the mGluR3 antagonist LY-341495. Furthermore, treatment of NSPCs with AMPA, kainic acid, or the kainate receptor-specific agonist (RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl)propanoic acid mimicked the responses seen with glutamate both alone and in the setting of oxidative stress. These findings offer important insights into potential mechanisms to enhance NSPC survival and implicate a potential role for glutamate in promoting NSPC survival and proliferation after traumatic SCI.

Toll-like Receptor 2: A Novel Therapeutic Target for Ischemic White Matter Injury and Oligodendrocyte Death

PubMed Central

Choi, Jun Young

2017-01-01

Despite paramount clinical significance of white matter stroke, there is a paucity of researches on the pathomechanism of ischemic white matter damage and accompanying oligodendrocyte (OL) death. Therefore, a large gap exists between clinical needs and laboratory researches in this disease entity. Recent works have started to elucidate cellular and molecular basis of white matter injury under ischemic stress. In this paper, we briefly introduce white matter stroke from a clinical point of view and review pathophysiology of ischemic white matter injury characterized by OL death and demyelination. We present a series of evidence that Toll-like receptor 2 (TLR2), one of the membranous pattern recognition receptors, plays a cell-autonomous protective role in ischemic OL death and ensuing demyelination. Moreover, we also discuss our recent findings that its endogenous ligand, high-mobility group box 1 (HMGB1), is released from dying OLs and exerts autocrine trophic effects on OLs and myelin sheath under ischemic condition. We propose that modulation of TLR2 and its endogenous ligand HMGB1 can be a novel therapeutic target for ischemic white matter disease. PMID:28912641

Protection of adult rat cardiac myocytes from ischemic cell death: role of caveolar microdomains and delta-opioid receptors.

PubMed

Patel, Hemal H; Head, Brian P; Petersen, Heidi N; Niesman, Ingrid R; Huang, Diane; Gross, Garrett J; Insel, Paul A; Roth, David M

2006-07-01

The role of caveolae, membrane microenvironments enriched in signaling molecules, in myocardial ischemia is poorly defined. In the current study, we used cardiac myocytes prepared from adult rats to test the hypothesis that opioid receptors (OR), which are capable of producing cardiac protection in vivo, promote cardiac protection in cardiac myocytes in a caveolae-dependent manner. We determined protein expression and localization of delta-OR (DOR) using coimmunohistochemistry, caveolar fractionation, and immunoprecipitations. DOR colocalized in fractions with caveolin-3 (Cav-3), a structural component of caveolae in muscle cells, and could be immunoprecipitated by a Cav-3 antibody. Immunohistochemistry confirmed plasma membrane colocalization of DOR with Cav-3. Cardiac myocytes were subjected to simulated ischemia (2 h) or an ischemic preconditioning (IPC) protocol (10 min ischemia, 30 min recovery, 2 h ischemia) in the presence and absence of methyl-beta-cyclodextrin (MbetaCD, 2 mM), which binds cholesterol and disrupts caveolae. We also assessed the cardiac protective effects of SNC-121 (SNC), a selective DOR agonist, on cardiac myocytes with or without MbetaCD and MbetaCD preloaded with cholesterol. Ischemia, simulated by mineral oil layering to inhibit gas exchange, promoted cardiac myocyte cell death (trypan blue staining), a response blunted by SNC (37 +/- 3 vs. 59 +/- 3% dead cells in the presence and absence of 1 muM SNC, respectively, P < 0.01) or by use of the IPC protocol (35 +/- 4 vs. 62 +/- 3% dead cells, P < 0.01). MbetaCD treatment, which disrupted caveolae (as detected by electron microscopy), fully attenuated the protective effects of IPC or SNC, resulting in cell death comparable to that of the ischemic group. By contrast, SNC-induced protection was not abrogated in cells incubated with cholesterol-saturated MbetaCD, which maintained caveolae structure and function. These findings suggest a key role for caveolae, perhaps through enrichment of

Death receptor and mitochondria-mediated hepatocyte apoptosis underlies liver dysfunction in rats exposed to organic pollutants from drinking water

PubMed Central

Yang, Guanghong; Zhou, Zhiwei; Cen, Yanli; Gui, Xiaolin; Zeng, Qibing; Ao, Yunxia; Li, Qian; Wang, Shiran; Li, Jun; Zhang, Aihua

2015-01-01

Persistent organic pollutants in drinking water impose a substantial risk to the health of human beings, but the evidence for liver toxic effect and the underlying mechanism is scarce. This study aimed to examine the liver toxicity and elucidate the molecular mechanism of organic pollutants in drinking water in normal human liver cell line L02 cells and rats. The data showed that organic extraction from drinking water remarkably impaired rat liver function, evident from the increase in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase, and decrease in the serum level of total protein and albumin. Organic extraction dose-dependently induced apoptotic cell death in rat liver and L02 cells. Administration of rats with organic extraction promoted death receptor signaling pathway through the increase in gene and protein expression level of Fas and FasL. Treatment of rats with organic extraction also induced mitochondria-mediated apoptosis via increasing the expression level of proapoptotic protein, Bax, but decreasing the expression level of antiapoptotic protein, Bcl-2, resulting in an upregulation of cytochrome c and activation of caspase cascade at both transcriptional and post-transcriptional levels. Moreover, organic extraction enhanced rat liver glutathione S-transferases activity and reactive oxygen species generation, and upregulated aryl hydrocarbon receptor and glutathione S-transferase A1 at both transcriptional and translational levels. Collectively, the results indicate that organic extraction from drinking water impairs liver function, with the involvement of death receptor and mitochondria-mediated apoptosis in rats. The results provide evidence and molecular mechanisms for organic pollutants in drinking water-induced liver dysfunction, which may help prevent and treat organic extraction-induced liver injury. PMID:26316710

Death receptor and mitochondria-mediated hepatocyte apoptosis underlies liver dysfunction in rats exposed to organic pollutants from drinking water.

PubMed

Yang, Guanghong; Zhou, Zhiwei; Cen, Yanli; Gui, Xiaolin; Zeng, Qibing; Ao, Yunxia; Li, Qian; Wang, Shiran; Li, Jun; Zhang, Aihua

2015-01-01

Persistent organic pollutants in drinking water impose a substantial risk to the health of human beings, but the evidence for liver toxic effect and the underlying mechanism is scarce. This study aimed to examine the liver toxicity and elucidate the molecular mechanism of organic pollutants in drinking water in normal human liver cell line L02 cells and rats. The data showed that organic extraction from drinking water remarkably impaired rat liver function, evident from the increase in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase, and decrease in the serum level of total protein and albumin. Organic extraction dose-dependently induced apoptotic cell death in rat liver and L02 cells. Administration of rats with organic extraction promoted death receptor signaling pathway through the increase in gene and protein expression level of Fas and FasL. Treatment of rats with organic extraction also induced mitochondria-mediated apoptosis via increasing the expression level of proapoptotic protein, Bax, but decreasing the expression level of antiapoptotic protein, Bcl-2, resulting in an upregulation of cytochrome c and activation of caspase cascade at both transcriptional and post-transcriptional levels. Moreover, organic extraction enhanced rat liver glutathione S-transferases activity and reactive oxygen species generation, and upregulated aryl hydrocarbon receptor and glutathione S-transferase A1 at both transcriptional and translational levels. Collectively, the results indicate that organic extraction from drinking water impairs liver function, with the involvement of death receptor and mitochondria-mediated apoptosis in rats. The results provide evidence and molecular mechanisms for organic pollutants in drinking water-induced liver dysfunction, which may help prevent and treat organic extraction-induced liver injury.

MEK inhibitor U0126 interferes with immunofluorescence analysis of apoptotic cell death.

PubMed

Blank, Norbert; Burger, Renate; Duerr, Birgit; Bakker, Frank; Wohlfarth, Anika; Dumitriu, Ingrid; Kalden, Joachim R; Herrmann, Martin

2002-08-01

Binding of extracellular growth factors to cell surface receptors often results in activation of the mitogen-activated protein kinase (MAPK). MAPK is regulated by MAPK kinase, also called MEK. Deprivation of growth factors during cell culture or intracellular MEK inhibition leads to inhibition of proliferation and apoptotic cell death. Besides other techniques, apoptotic cells can be identified by phosphatidylserine (PS) exposure and exclusion of membrane-impermeant propidium iodide (PI). We investigated the limitations of detection of apoptotic cell death and cytofluorometry in cells cultured in the presence of the MEK inhibitor U0126. Apoptotic cell death was induced in the plasmacytoma cell line INA-6, in peripheral blood mononuclear cells (PBMC), and in cultured T lymphoblasts by deprivation of interleukin-6 (IL-6) or by incubation with the MEK inhibitor U0126. Apoptotic cell death was quantified by flow cytometry using annexin V/propidium iodide (AxV/PI) double staining. U0126-treated cells dramatically changed their fluorescence pattern during cell culture. If AxV/PI staining is employed to detect apoptotic cell death, the background fluorescence mimicks PS exposure on viable cells. The compound itself has no intrinsic fluorescence in vitro but develops an intensive fluorescence during cell culture which can be observed in all fluorescence channels with a predominance in the FL1 channel (525 nm). We further demonstrate that at least some of the U0126-induced background fluorescence is dependent on cellular uptake and intracellular modifications or cellular responses. These results demonstrate that appropriate controls for every single time point are necessary if fluorescence analyses are performed in the presence of chemical enzyme inhibitors. In the case of MEK inhibitors, either the use of PD098059 or PD184352 as an alternative for U0126 or nonfluorometric methods for detection of apoptosis should be considered. Copyright 2002 Wiley-Liss, Inc.

Heteroreceptor Complexes Formed by Dopamine D1, Histamine H3, and N-Methyl-D-Aspartate Glutamate Receptors as Targets to Prevent Neuronal Death in Alzheimer's Disease.

PubMed

Rodríguez-Ruiz, Mar; Moreno, Estefanía; Moreno-Delgado, David; Navarro, Gemma; Mallol, Josefa; Cortés, Antonio; Lluís, Carme; Canela, Enric I; Casadó, Vicent; McCormick, Peter J; Franco, Rafael

2017-08-01

Alzheimer's disease (AD) is a neurodegenerative disorder causing progressive memory loss and cognitive dysfunction. Anti-AD strategies targeting cell receptors consider them as isolated units. However, many cell surface receptors cooperate and physically contact each other forming complexes having different biochemical properties than individual receptors. We here report the discovery of dopamine D 1 , histamine H 3 , and N-methyl-D-aspartate (NMDA) glutamate receptor heteromers in heterologous systems and in rodent brain cortex. Heteromers were detected by co-immunoprecipitation and in situ proximity ligation assays (PLA) in the rat cortex where H 3 receptor agonists, via negative cross-talk, and H 3 receptor antagonists, via cross-antagonism, decreased D 1 receptor agonist signaling determined by ERK1/2 or Akt phosphorylation, and counteracted D 1 receptor-mediated excitotoxic cell death. Both D 1 and H 3 receptor antagonists also counteracted NMDA toxicity suggesting a complex interaction between NMDA receptors and D 1 -H 3 receptor heteromer function. Likely due to heteromerization, H 3 receptors act as allosteric regulator for D 1 and NMDA receptors. By bioluminescence resonance energy transfer (BRET), we demonstrated that D 1 or H 3 receptors form heteromers with NR1A/NR2B NMDA receptor subunits. D 1 -H 3 -NMDA receptor complexes were confirmed by BRET combined with fluorescence complementation. The endogenous expression of complexes in mouse cortex was determined by PLA and similar expression was observed in wild-type and APP/PS1 mice. Consistent with allosteric receptor-receptor interactions within the complex, H 3 receptor antagonists reduced NMDA or D 1 receptor-mediated excitotoxic cell death in cortical organotypic cultures. Moreover, H 3 receptor antagonists reverted the toxicity induced by ß 1-42 -amyloid peptide. Thus, histamine H 3 receptors in D 1 -H 3 -NMDA heteroreceptor complexes arise as promising targets to prevent neurodegeneration.

Antigen-Specific Immune Modulation Targets mTORC1 Function To Drive Chemokine Receptor-Mediated T Cell Tolerance.

PubMed

Chen, Weirong; Wan, Xiaoxiao; Ukah, Tobechukwu K; Miller, Mindy M; Barik, Subhasis; Cattin-Roy, Alexis N; Zaghouani, Habib

2016-11-01

To contain autoimmunity, pathogenic T cells must be eliminated or diverted from reaching the target organ. Recently, we defined a novel form of T cell tolerance whereby treatment with Ag downregulates expression of the chemokine receptor CXCR3 and prevents diabetogenic Th1 cells from reaching the pancreas, leading to suppression of type 1 diabetes (T1D). This report defines the signaling events underlying Ag-induced chemokine receptor-mediated tolerance. Specifically, we show that the mammalian target of rapamycin complex 1 (mTORC1) is a major target for induction of CXCR3 downregulation and crippling of Th1 cells. Indeed, Ag administration induces upregulation of programmed death-ligand 1 on dendritic cells in a T cell-dependent manner. In return, programmed death-ligand 1 interacts with the constitutively expressed programmed death-1 on the target T cells and stimulates docking of Src homology 2 domain-containing tyrosine phosphatase 2 phosphatase to the cytoplasmic tail of programmed death-1. Active Src homology 2 domain-containing tyrosine phosphatase 2 impairs the signaling function of the PI3K/protein kinase B (AKT) pathway, leading to functional defect of mTORC1, downregulation of CXCR3 expression, and suppression of T1D. Thus, mTORC1 component of the metabolic pathway serves as a target for chemokine receptor-mediated T cell tolerance and suppression of T1D. Copyright © 2016 by The American Association of Immunologists, Inc.

Attenuation of Aβ{sub 25–35}-induced parallel autophagic and apoptotic cell death by gypenoside XVII through the estrogen receptor-dependent activation of Nrf2/ARE pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Xiangbao; Wang, Min; Sun, Guibo, E-mail: sunguibo@126.com

Amyloid-beta (Aβ) has a pivotal function in the pathogenesis of Alzheimer's disease. To investigate Aβ neurotoxicity, we used an in vitro model that involves Aβ{sub 25–35}-induced cell death in the nerve growth factor-induced differentiation of PC12 cells. Aβ{sub 25–35} (20 μM) treatment for 24 h caused apoptotic cell death, as evidenced by significant cell viability reduction, LDH release, phosphatidylserine externalization, mitochondrial membrane potential disruption, cytochrome c release, caspase-3 activation, PARP cleavage, and DNA fragmentation in PC12 cells. Aβ{sub 25–35} treatment led to autophagic cell death, as evidenced by augmented GFP-LC3 puncta, conversion of LC3-I to LC3-II, and increased LC3-II/LC3-I ratio.more » Aβ{sub 25–35} treatment induced oxidative stress, as evidenced by intracellular ROS accumulation and increased production of mitochondrial superoxide, malondialdehyde, protein carbonyl, and 8-OHdG. Phytoestrogens have been proved to be protective against Aβ-induced neurotoxicity and regarded as relatively safe targets for AD drug development. Gypenoside XVII (GP-17) is a novel phytoestrogen isolated from Gynostemma pentaphyllum or Panax notoginseng. Pretreatment with GP-17 (10 μM) for 12 h increased estrogen response element reporter activity, activated PI3K/Akt pathways, inhibited GSK-3β, induced Nrf2 nuclear translocation, augmented antioxidant responsive element enhancer activity, upregulated heme oxygenase 1 (HO-1) expression and activity, and provided protective effects against Aβ{sub 25–35}-induced neurotoxicity, including oxidative stress, apoptosis, and autophagic cell death. In conclusion, GP-17 conferred protection against Aβ{sub 25–35}-induced neurotoxicity through estrogen receptor-dependent activation of PI3K/Akt pathways, inactivation of GSK-3β and activation of Nrf2/ARE/HO-1 pathways. This finding might provide novel insights into understanding the mechanism for neuroprotective effects of

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

Delayed innocent bystander cell death following hypoxia in Caenorhabditis elegans.

PubMed

Sun, C-L; Kim, E; Crowder, C M

2014-04-01

After hypoxia, cells may die immediately or have a protracted course, living or dying depending on an incompletely understood set of cell autonomous and nonautonomous factors. In stroke, for example, some neurons are thought to die from direct hypoxic injury by cell autonomous primary mechanisms, whereas other so called innocent bystander neurons die from factors released from the primarily injured cells. A major limitation in identifying these factors is the inability of current in vivo models to selectively target a set of cells for hypoxic injury so that the primarily injured cells and the innocent bystanders are clearly delineated. In order to develop such a model, we generated transgenic Caenorhabditis elegans strains where 2-3% of somatic cells were made selectively sensitive to hypoxia. This was accomplished by cell type-specific wild-type rescue in either pharyngeal myocytes or GABAergic neurons of a hypoxia resistance-producing translation factor mutation. Surprisingly, hypoxic targeting of these relatively small subsets of non-essential cells produced widespread innocent bystander cell injury, behavioral dysfunction and eventual organismal death. The hypoxic injury phenotypes of the myocyte or neuron sensitized strains were virtually identical. Using this model, we show that the C. elegans insulin receptor/FOXO transcription factor pathway improves survival when activated only after hypoxic injury and blocks innocent bystander death.

Attenuation of cadmium-induced necrotic cell death by necrostatin-1: Potential necrostatin-1 acting sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, T.-S.; Yang, P.-M.; Tsai, J.-S.

2009-03-01

Cadmium (Cd) induces necrotic death in Chinese hamster ovary (CHO) K1 cells and we have established the responsible signaling pathway. Reportedly, necrostatin-1 (Nec-1) rescues cells from necrotic death by mediating through the death domain receptor (DR) signaling pathway. We show here that Nec-1 also effectively attenuates necrotic death triggered by Cd. Two other treatments that cause necrotic cell death, one can (z-VAD-fmk/TNF-{alpha} on U937 cells) and the other cannot (etherynic acid (EA) on DLD-1 cells) be rescued by Nec-1, were also studied in parallel for comparison. Results show that Nec-1 is ineffectual in modulating intracellular calcium contents, calpain activity (amore » downstream protease), or reactive oxygen species production. It can counteract the reduction in mitochondrial membrane potential (MMP) caused by treating CHO K1 or U937 cells with necrosis-inducing agent. However, this effect was not found in EA-treated DLD-1 cells. Notably, Nec-1 elevates NF-{kappa}B activity in the presence or absence of necrosis-inducing agents. Our study shows that, in addition to DR-mediated necrosis, Nec-1 is effective in attenuating Cd-induced necrosis. It rescues cells with reduced MMP implying that mitochondrion is its major acting site.« less

Role of transglutaminase 2 in A1 adenosine receptor- and β2-adrenoceptor-mediated pharmacological pre- and post-conditioning against hypoxia-reoxygenation-induced cell death in H9c2 cells.

PubMed

Vyas, Falguni S; Nelson, Carl P; Dickenson, John M

2018-01-15

Pharmacologically-induced pre- and post-conditioning represent attractive therapeutic strategies to reduce ischaemia/reperfusion injury during cardiac surgery and following myocardial infarction. We have previously reported that transglutaminase 2 (TG2) activity is modulated by the A 1 adenosine receptor and β 2 -adrenoceptor in H9c2 cardiomyoblasts. The primary aim of this study was to determine the role of TG2 in A 1 adenosine receptor and β 2 -adrenoceptor-induced pharmacological pre- and post-conditioning in the H9c2 cells. H9c2 cells were exposed to 8h hypoxia (1% O 2 ) followed by 18h reoxygenation, after which cell viability was assessed by monitoring mitochondrial reduction of MTT, lactate dehydrogenase release and caspase-3 activation. N 6 -cyclopentyladenosine (CPA; A 1 adenosine receptor agonist), formoterol (β 2 -adrenoceptor agonist) or isoprenaline (non-selective β-adrenoceptor agonist) were added before hypoxia/reoxygenation (pre-conditioning) or at the start of reoxygenation following hypoxia (post-conditioning). Pharmacological pre- and post-conditioning with CPA and isoprenaline significantly reduced hypoxia/reoxygenation-induced cell death. In contrast, formoterol did not elicit protection. Pre-treatment with pertussis toxin (G i/o -protein inhibitor), DPCPX (A 1 adenosine receptor antagonist) or TG2 inhibitors (Z-DON and R283) attenuated the A 1 adenosine receptor-induced pharmacological pre- and post-conditioning. Similarly, pertussis toxin, ICI 118,551 (β 2 -adrenoceptor antagonist) or TG2 inhibition attenuated the isoprenaline-induced cell survival. Knockdown of TG2 using small interfering RNA (siRNA) attenuated CPA and isoprenaline-induced pharmacological pre- and post-conditioning. Finally, proteomic analysis following isoprenaline treatment identified known (e.g. protein S100-A6) and novel (e.g. adenine phosphoribosyltransferase) protein substrates for TG2. These results have shown that A 1 adenosine receptor and β 2 -adrenoceptor

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

Signaling mechanisms of apoptosis-like programmed cell death in unicellular eukaryotes.

PubMed

Shemarova, Irina V

2010-04-01

In unicellular eukaryotes, apoptosis-like cell death occurs during development, aging and reproduction, and can be induced by environmental stresses and exposure to toxic agents. The essence of the apoptotic machinery in unicellular organisms is similar to that in mammals, but the apoptotic signal network is less complex and of more ancient origin. The review summarizes current data about key apoptotic proteins and mechanisms of the transduction of apoptotic signals by caspase-like proteases and mitochondrial apoptogenic proteins in unicellular eukaryotes. The roles of receptor-dependent and receptor-independent caspase cascades are reviewed. 2010 Elsevier Inc. All rights reserved.

GPR30 Activation Contributes to the Puerarin-Mediated Neuroprotection in MPP+-Induced SH-SY5Y Cell Death.

PubMed

Cheng, Yue-Fa; Zhu, Guoqi; Wu, Qing-Wen; Xie, Yue-Sheng; Jiang, Yan; Guo, Lan; Guan, Ya-Li; Liu, Ying-Shuo; Zhang, Jun

2017-02-01

The neuroprotective action of puerarin in Parkinson's disease (PD) models has been well investigated. However, the mechanisms involved in protection have not been completely understood. G protein-coupled receptor 30 (GPR30) is a G protein-coupled estrogen receptor and considered a potential target in the neuroprotection against PD. In this study, we investigated whether puerarin prevented against 1-methyl-4-phenylpyridinium (MPP + )-induced cell death via GPR30. Our results showed that the GPR30 agonist, G1, exhibited puerarin-mediated neuroprotection against MPP + -induced cell death of SH-SY5Y cells. This protective action was reversed by the GPR30 antagonist. Moreover, a time- and concentration-dependent effect of puerarin on GPR30 expression was verified at the protein level but not at the mRNA level. Further, we showed that an mTor-dependent new GPR30 synthesis contributed to the protection conferred by puerarin. Finally, glial cell line-derived neurotrophic factor (GDNF) levels were enhanced by puerarin and G1 in both control and MPP + -lesioned cells via GPR30. Taken together, our data strongly suggest that puerarin prevents MPP + -induced cell death via facilitating GPR30 expression and GDNF release.

Harnessing tumor necrosis factor receptors to enhance antitumor activities of drugs.

PubMed

Muntané, Jordi

2011-10-17

Cancer is the second-leading cause of death in the U.S. behind heart disease and over stroke. The hallmarks of cancer comprise six biological capabilities acquired during the multistep development of human tumors. The inhibition of cell death pathways is one of these tumor characteristics which also include sustained proliferative signaling, evading growth suppressor signaling, replicative immortality, angiogenesis, and promotion of invasion and metastasis. Cell death is mediated through death receptor (DR) stimulation initiated by specific ligands that transmit signaling to the cell death machinery or through the participation of mitochondria. Cell death involving DR is mediated by the superfamily of tumor necrosis factor receptor (TNF-R) which includes TNF-R type I, CD95, DR3, TNF-related apoptosis-inducing ligand (TRAIL) receptor-1 (TRAIL-R1) and -2 (TRAIL-R2), DR6, ectodysplasin A (EDA) receptor (EDAR), and the nerve growth factor (NGF) receptor (NGFR). The expression of these receptors in healthy and tumor cells induces treatment side effects that limit the systemic administration of cell death-inducing therapies. The present review is focused on the different therapeutic strategies such as targeted antibodies or small molecules addressed to selective stimulated DR-mediated apoptosis or reduce cell proliferation in cancer cells.

Fluid shear stress sensitizes cancer cells to receptor-mediated apoptosis via trimeric death receptors

NASA Astrophysics Data System (ADS)

Mitchell, Michael J.; King, Michael R.

2013-01-01

Cancer metastasis, the process of cancer cell migration from a primary to distal location, typically leads to a poor patient prognosis. Hematogenous metastasis is initiated by intravasation of circulating tumor cells (CTCs) into the bloodstream, which are then believed to adhere to the luminal surface of the endothelium and extravasate into distal locations. Apoptotic agents such as tumor necrosis factor apoptosis-inducing ligand (TRAIL), whether in soluble ligand form or expressed on the surface of natural killer cells, have shown promise in treating CTCs to reduce the probability of metastasis. The role of hemodynamic shear forces in altering the cancer cell response to apoptotic agents has not been previously investigated. Here, we report that human colon cancer COLO 205 and prostate cancer PC-3 cells exposed to a uniform fluid shear stress in a cone-and-plate viscometer become sensitized to TRAIL-induced apoptosis. Shear-induced sensitization directly correlates with the application of fluid shear stress, and TRAIL-induced apoptosis increases in a fluid shear stress force- and time-dependent manner. In contrast, TRAIL-induced necrosis is not affected by the application fluid shear stress. Interestingly, fluid shear stress does not sensitize cancer cells to apoptosis when treated with doxorubicin, which also induces apoptosis in cancer cells. Caspase inhibition experiments reveal that shear stress-induced sensitization to TRAIL occurs via caspase-dependent apoptosis. These results suggest that physiological fluid shear forces can modulate receptor-mediated apoptosis of cancer cells in the presence of apoptotic agents.

TRAIL Death Receptor-4 Expression Positively Correlates With the Tumor Grade in Breast Cancer Patients With Invasive Ductal Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanlioglu, Ahter D.; Department of Medical Biology and Genetics, Akdeniz University Faculty of Medicine, Antalya; Korcum, Aylin F.

2007-11-01

Purpose: Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) selectively induces apoptosis in cancer cells but not in normal cells, and a number of clinical trials have recently been initiated to test the safety and antitumoral potential of TRAIL in cancer patients. Four different receptors have been identified to interact with TRAIL: two are death-inducing receptors (TRAIL-R1 [DR4] and TRAIL-R2 [DR5]), whereas the other two (TRAIL-R3 [DcR1] and TRAIL-R4 [DcR2]) do not induce death upon ligation and are believed to counteract TRAIL-induced cytotoxicity. Because high levels of DcR2 expression have recently been correlated with carcinogenesis in the prostate and lung, thismore » study investigated the importance of TRAIL and TRAIL receptor expression in breast cancer patients with invasive ductal carcinoma, taking various prognostic markers into consideration. Methods and Materials: Immunohistochemical analyses were performed on 90 breast cancer patients with invasive ductal carcinoma using TRAIL and TRAIL receptor-specific antibodies. Age, menopausal status, tumor size, lymph node status, tumor grade, lymphovascular invasion, perineural invasion, extracapsular tumor extension, presence of an extensive intraductal component, multicentricity, estrogen and progesterone receptor status, and CerbB2 expression levels were analyzed with respect to TRAIL/TRAIL receptor expression patterns. Results: The highest TRAIL receptor expressed in patients with invasive ductal carcinoma was DR4. Although progesterone receptor-positive patients exhibited lower DR5 expression, CerbB2-positive tissues displayed higher levels of both DR5 and TRAIL expressions. Conclusions: DR4 expression positively correlates with the tumor grade in breast cancer patients with invasive ductal carcinoma.« less

The Capsicum annuum class IV chitinase ChitIV interacts with receptor-like cytoplasmic protein kinase PIK1 to accelerate PIK1-triggered cell death and defence responses.

PubMed

Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

2015-04-01

The pepper receptor-like cytoplasmic protein kinase, CaPIK1, which mediates signalling of plant cell death and defence responses was previously identified. Here, the identification of a class IV chitinase, CaChitIV, from pepper plants (Capsicum annuum), which interacts with CaPIK1 and promotes CaPIK1-triggered cell death and defence responses, is reported. CaChitIV contains a signal peptide, chitin-binding domain, and glycol hydrolase domain. CaChitIV expression was up-regulated by Xanthomonas campestris pv. vesicatoria (Xcv) infection. Notably, avirulent Xcv infection rapidly induced CaChitIV expression in pepper leaves. Bimolecular fluorescence complementation and co-immunoprecipitation revealed that CaPIK1 interacts with CaChitIV in planta, and that the CaPIK1-CaChitIV complex is localized mainly in the cytoplasm and plasma membrane. CaChitIV is also localized in the endoplasmic reticulum. Transient co-expression of CaChitIV with CaPIK1 enhanced CaPIK1-triggered cell death response and reactive oxygen species (ROS) and nitric oxide (NO) bursts. Co-silencing of both CaChitIV and CaPIK1 in pepper plants conferred enhanced susceptibility to Xcv infection, which was accompanied by a reduced induction of cell death response, ROS and NO bursts, and defence response genes. Ectopic expression of CaPIK1 in Arabidopsis enhanced basal resistance to Hyaloperonospora arabidopsidis infection. Together, the results suggest that CaChitIV positively regulates CaPIK1-triggered cell death and defence responses through its interaction with CaPIK1. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Fluoxetine Prevents Oligodendrocyte Cell Death by Inhibiting Microglia Activation after Spinal Cord Injury

PubMed Central

Lee, Jee Y.; Kang, So R.

2015-01-01

Abstract Oligodendrocyte cell death and axon demyelination after spinal cord injury (SCI) are known to be important secondary injuries contributing to permanent neurological disability. Thus, blocking oligodendrocyte cell death should be considered for therapeutic intervention after SCI. Here, we demonstrated that fluoxetine, an antidepressant drug, alleviates oligodendrocyte cell death by inhibiting microglia activation after SCI. After injury at the T9 level with a Precision Systems and Instrumentation (Lexington, KY) device, fluoxetine (10 mg/kg, intraperitoneal) was administered once a day for the indicated time points. Immunostaining with CD11b (OX-42) antibody and quantification analysis showed that microglia activation was significantly inhibited by fluoxetine at 5 days after injury. Fluoxetine also significantly inhibited activation of p38 mitogen-activated protein kinase (p38-MAPK) and expression of pro-nerve growth factor (pro-NGF), which is known to mediate oligodendrocyte cell death through the p75 neurotrophin receptor after SCI. In addition, fluoxetine attenuated activation of Ras homolog gene family member A and decreased the level of phosphorylated c-Jun and, ultimately, alleviated caspase-3 activation and significantly reduced cell death of oligodendrocytes at 5 days after SCI. Further, the decrease of myelin basic protein, myelin loss, and axon loss in white matter was also significantly blocked by fluoxetine, as compared to vehicle control. These results suggest that fluoxetine inhibits oligodendrocyte cell death by inhibiting microglia activation and p38-MAPK activation, followed by pro-NGF production after SCI, and provide a potential usage of fluoxetine for a therapeutic agent after acute SCI in humans. PMID:25366938

Construction of an anti-programmed death-ligand 1 chimeric antigen receptor and determination of its antitumor function with transduced cells

PubMed Central

Xie, Jiasen; Zhou, Zishan; Jiao, Shunchang; Li, Xiaokun

2018-01-01

A chimeric antigen receptor (CAR) is a type of fusion protein that comprises an antigen-recognition domain and signaling domains. In the present study, a programmed death-ligand 1 (PD-L1)-specific CAR, comprised of a single-chain variable fragment (scFv) derived from a monoclonal antibody, co-stimulatory domains of cluster of differentiation (CD) 28 and 4-1BB and a T-cell-activation domain derived from CD3ζ, was designed. The construction was cloned and packaged into the lentiviral vector pLVX. Flow cytometry confirmed that peripheral blood mononuclear cells were efficiently transduced and that the CAR was successfully expressed on T cells. The cytotoxicity of transduced T cells was detected using PD-L1-positive NCI-H358 bronchioalveolar carcinoma cells and A549 lung adenocarcinoma cells (with a low expression of PD-L1, only in the A549 cells). The results demonstrated mild cytotoxicity at an effector-to-target ratio of 10:1. An ELISA revealed a significant increase in the level of interferon-γ released from T cells transduced with scFv-28Bz when the cells were co-cultured with PD-L1-positive NCI-H358 cells, while interkeukin-2 and tumor necrosis factor-α levels remained unchanged. These data indicated a potential method for the treatment of solid tumors. PMID:29928397

Angiotensin II type 1 receptor blocker telmisartan induces apoptosis and autophagy in adult T-cell leukemia cells.

PubMed

Kozako, Tomohiro; Soeda, Shuhei; Yoshimitsu, Makoto; Arima, Naomichi; Kuroki, Ayako; Hirata, Shinya; Tanaka, Hiroaki; Imakyure, Osamu; Tone, Nanako; Honda, Shin-Ichiro; Soeda, Shinji

2016-05-01

Adult T-cell leukemia/lymphoma (ATL), an aggressive T-cell malignancy that develops after long-term infection with human T-cell leukemia virus (HTLV-1), requires new treatments. Drug repositioning, reuse of a drug previously approved for the treatment of another condition to treat ATL, offers the possibility of reduced time and risk. Among clinically available angiotensin II receptor blockers, telmisartan is well known for its unique ability to activate peroxisome proliferator-activated receptor-γ, which plays various roles in lipid metabolism, cellular differentiation, and apoptosis. Here, telmisartan reduced cell viability and enhanced apoptotic cells via caspase activation in ex vivo peripheral blood monocytes from asymptomatic HTLV-1 carriers (ACs) or via caspase-independent cell death in acute-type ATL, which has a poor prognosis. Telmisartan also induced significant growth inhibition and apoptosis in leukemia cell lines via caspase activation, whereas other angiotensin II receptor blockers did not induce cell death. Interestingly, telmisartan increased the LC3-II-enriched protein fraction, indicating autophagosome accumulation and autophagy. Thus, telmisartan simultaneously caused caspase activation and autophagy. A hypertension medication with antiproliferation effects on primary and leukemia cells is intriguing. Patients with an early diagnosis of ATL are generally monitored until the disease progresses; thus, suppression of progression from AC and indolent ATL to acute ATL is important. Our results suggest that telmisartan is highly effective against primary cells and leukemia cell lines in caspase-dependent and -independent manners, and its clinical use may suppress acute transformation and improve prognosis of patients with this mortal disease. This is the first report demonstrating a cell growth-inhibitory effect of telmisartan in fresh peripheral blood mononuclear cells from leukemia patients.

Bubbling cell death: A hot air balloon released from the nucleus in the cold

PubMed Central

2016-01-01

Cell death emanating from the nucleus is largely unknown. In our recent study, we determined that when temperature is lowered in the surrounding environment, apoptosis stops and bubbling cell death (BCD) occurs. The study concerns the severity of frostbite. When exposed to severe cold and strong ultraviolet (UV) irradiation, people may suffer serious damages to the skin and internal organs. This ultimately leads to limb amputations, organ failure, and death. BCD is defined as “formation of a single bubble from the nucleus per cell and release of this swelling bubble from the cell surface to extracellular space that causes cell death.” When cells are subjected to UV irradiation and/or brief cold shock (4℃ for 5 min) and then incubated at room temperature or 4℃ for time-lapse microscopy, each cell releases an enlarging nuclear gas bubble containing nitric oxide. Certain cells may simultaneously eject hundreds or thousands of exosome-like particles. Unlike apoptosis, no phosphatidylserine flip-over, mitochondrial apoptosis, damage to Golgi complex, and chromosomal DNA fragmentation are shown in BCD. When the temperature is increased back at 37℃, bubble formation stops and apoptosis restarts. Mechanistically, proapoptotic WW domain-containing oxidoreductase and p53 block the protective TNF receptor adaptor factor 2 that allows nitric oxide synthase 2 to synthesize nitric oxide and bubble formation. In this mini-review, updated knowledge in cell death and the proposed molecular mechanism for BCD are provided. PMID:27075929

Structure and Interactions of the Human Programmed Cell Death 1 Receptor*

PubMed Central

Cheng, Xiaoxiao; Veverka, Vaclav; Radhakrishnan, Anand; Waters, Lorna C.; Muskett, Frederick W.; Morgan, Sara H.; Huo, Jiandong; Yu, Chao; Evans, Edward J.; Leslie, Alasdair J.; Griffiths, Meryn; Stubberfield, Colin; Griffin, Robert; Henry, Alistair J.; Jansson, Andreas; Ladbury, John E.; Ikemizu, Shinji; Carr, Mark D.; Davis, Simon J.

2013-01-01

PD-1, a receptor expressed by T cells, B cells, and monocytes, is a potent regulator of immune responses and a promising therapeutic target. The structure and interactions of human PD-1 are, however, incompletely characterized. We present the solution nuclear magnetic resonance (NMR)-based structure of the human PD-1 extracellular region and detailed analyses of its interactions with its ligands, PD-L1 and PD-L2. PD-1 has typical immunoglobulin superfamily topology but differs at the edge of the GFCC′ sheet, which is flexible and completely lacks a C″ strand. Changes in PD-1 backbone NMR signals induced by ligand binding suggest that, whereas binding is centered on the GFCC′ sheet, PD-1 is engaged by its two ligands differently and in ways incompletely explained by crystal structures of mouse PD-1·ligand complexes. The affinities of these interactions and that of PD-L1 with the costimulatory protein B7-1, measured using surface plasmon resonance, are significantly weaker than expected. The 3–4-fold greater affinity of PD-L2 versus PD-L1 for human PD-1 is principally due to the 3-fold smaller dissociation rate for PD-L2 binding. Isothermal titration calorimetry revealed that the PD-1/PD-L1 interaction is entropically driven, whereas PD-1/PD-L2 binding has a large enthalpic component. Mathematical simulations based on the biophysical data and quantitative expression data suggest an unexpectedly limited contribution of PD-L2 to PD-1 ligation during interactions of activated T cells with antigen-presenting cells. These findings provide a rigorous structural and biophysical framework for interpreting the important functions of PD-1 and reveal that potent inhibitory signaling can be initiated by weakly interacting receptors. PMID:23417675

A novel homozygous Fas ligand mutation leads to early protein truncation, abrogation of death receptor and reverse signaling and a severe form of the autoimmune lymphoproliferative syndrome.

PubMed

Nabhani, Schafiq; Hönscheid, Andrea; Oommen, Prasad T; Fleckenstein, Bernhard; Schaper, Jörg; Kuhlen, Michaela; Laws, Hans-Jürgen; Borkhardt, Arndt; Fischer, Ute

2014-12-01

We report a novel type of mutation in the death ligand FasL that was associated with a severe phenotype of the autoimmune lymphoproliferative syndrome in two patients. A frameshift mutation in the intracellular domain led to complete loss of FasL expression. Cell death signaling via its receptor and reverse signaling via its intracellular domain were completely abrogated. In vitro lymphocyte proliferation induced by weak T cell receptor stimulation could be blocked and cell death was induced by engagement of FasL in T cells derived from healthy individuals and a heterozygous carrier, but not in FasL-deficient patient derived cells. Expression of genes implicated in lymphocyte proliferation and activation (CCND1, NFATc1, NF-κB1) was increased in FasL-deficient T cells and could not be downregulated by FasL engagement as in healthy cells. Our data thus suggest, that deficiency in FasL reverse signaling may contribute to the clinical lymphoproliferative phenotype of ALPS. Copyright © 2014 Elsevier Inc. All rights reserved.

The Btk-dependent PIP5K1γ lipid kinase activation by Fas counteracts FasL-induced cell death.

PubMed

Rossin, Aurélie; Lounnas, Nadia; Durivault, Jérôme; Miloro, Giorgia; Gagnoux-Palacios, Laurent; Hueber, Anne-Odile

2017-11-01

The Fas/FasL system plays a critical role in death by apoptosis and immune escape of cancer cells. The Fas receptor being ubiquitously expressed in tissues, its apoptotic-inducing function, initiated upon FasL binding, is tightly regulated by several negative regulatory mechanisms to prevent inappropriate cell death. One of them, involving the non-receptor tyrosine kinase Btk, was reported mainly in B cells and only poorly described. We report here that Btk negatively regulates, through its tyrosine kinase activity, the FasL-mediated cell death in epithelial cell lines from colon cancer origin. More importantly, we show that Btk interacts not only with Fas but also with the phosphatidylinositol-4-phosphate 5-kinase, PIP5K1γ, which, upon stimulation by Fas ligand, is responsible of a rapid and transient synthesis of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P 2 ). This production requires both the presence and the tyrosine kinase activity of Btk, and participates in the negative regulation of FasL-mediated cell death since knocking down PIP5K1γ expression significantly strengthens the apoptotic signal upon FasL engagement. Altogether, our data demonstrate the cooperative role of Btk and PIP5K1γ in a FasL-induced PI(4,5)P 2 production, both proteins participating to the threshold setting of FasL-induced apoptotic commitment in colorectal cell lines.

Tropomyosin Receptor Kinase A Expression on Merkel Cell Carcinoma Cells.

PubMed

Wehkamp, Ulrike; Stern, Sophie; Krüger, Sandra; Hauschild, Axel; Röcken, Christoph; Egberts, Friederike

2017-11-01

Merkel cell carcinoma (MCC) is a malignant neuroendocrine skin tumor frequently associated with the Merkel cell polyomavirus. Immune checkpoint therapy showed remarkable results, although not all patients are responsive to this therapy. Anti-tropomyosin receptor kinase A (TrkA)-targeted treatment has shown promising results in several tumor entities. To determine TrkA expression in MCC as a rationale for potential targeted therapy. This case series study investigated the MCC specimens of 55 patients treated at the Department of Dermatology, University Hospital of Schleswig-Holstein, Kiel, Germany, from January 1, 2005, through December 31, 2015. Thirty-nine of the 55 samples were suitable for further histopathologic examination. Expression of TrkA was explored by immunohistochemical analysis. Diagnosis of MCC was confirmed by staining positive for cytokeratin 20 (CK20) and synaptophysin. Expression of TrkA on the tumor cells. Specimens of 39 patients (21 women and 18 men; mean [SD] age, 75.0 [7.8] years) underwent immunohistochemical investigation. Thirty-eight of 38 specimens expressed CK20 and synaptophysin on the MCC tumor cells (100% expression). Merkel cell polyomavirus was detected in 32 of 38 specimens (84%). Tropomyosin receptor kinase A was found in all 36 evaluable specimens on the tumor cells; 34 (94%) showed a weak and 2 (6%) showed a strong cytoplasmic expression. In addition, strongly positive perinuclear dots were observed in 30 of 36 specimens (83%). Tropomyosin receptor kinase A was expressed on MCC tumor cells in 100% of evaluable specimens. This result may lead to the exploration of new targeted treatment options in MCC, especially for patients who do not respond to anti-programmed cell death protein 1 treatment.

MPP+ induces necrostatin-1- and ferrostatin-1-sensitive necrotic death of neuronal SH-SY5Y cells.

PubMed

Ito, Keisuke; Eguchi, Yutaka; Imagawa, Yusuke; Akai, Shuji; Mochizuki, Hideki; Tsujimoto, Yoshihide

2017-01-01

Regulation of cell death is potentially a powerful treatment modality for intractable diseases such as neurodegenerative diseases. Although there have been many reports about the possible involvement of various types of cell death in neurodegenerative diseases, it is still unclear exactly how neurons die in patients with these diseases, thus treatment strategies based on cell death regulation have not been established yet. To obtain some insight into the mechanisms of cell death involved in neurodegenerative diseases, we studied the effect of 1-methyl-4-phenylpyridinium (MPP+) on the human neuroblastoma cell line SH-SY5Y (a widely used model of Parkinson's disease). We found that MPP+ predominantly induced non-apoptotic death of neuronally differentiated SH-SY5Y cells. This cell death was strongly inhibited by necrostatin-1 (Nec-1), a necroptosis inhibitor, and by an indole-containing compound (3,3'-diindolylmethane: DIM). However, it occurred independently of receptor-interacting serine/threonine-protein kinase 1/3 (RIP1/RIP3), indicating that this form of cell death was not necroptosis. MPP+-induced cell death was also inhibited by several inhibitors of ferroptosis, including ferrostatin-1 (Fer-1). Although MPP+-induced death and ferroptosis shared some features, such as occurrence of lipid peroxidation and inhibition by Fer-1, MPP+-induced death seemed to be distinct from ferroptosis because MPP+-induced death (but not ferroptosis) was inhibited by Nec-1, was independent of p53, and was accompanied by ATP depletion and mitochondrial swelling. Further investigation of MPP+-induced non-apoptotic cell death may be useful for understanding the mechanisms of neuronal loss and for treatment of neurodegenerative diseases such as Parkinson's disease.

MPP+ induces necrostatin-1- and ferrostatin-1-sensitive necrotic death of neuronal SH-SY5Y cells

PubMed Central

Ito, Keisuke; Eguchi, Yutaka; Imagawa, Yusuke; Akai, Shuji; Mochizuki, Hideki; Tsujimoto, Yoshihide

2017-01-01

Regulation of cell death is potentially a powerful treatment modality for intractable diseases such as neurodegenerative diseases. Although there have been many reports about the possible involvement of various types of cell death in neurodegenerative diseases, it is still unclear exactly how neurons die in patients with these diseases, thus treatment strategies based on cell death regulation have not been established yet. To obtain some insight into the mechanisms of cell death involved in neurodegenerative diseases, we studied the effect of 1-methyl-4-phenylpyridinium (MPP+) on the human neuroblastoma cell line SH-SY5Y (a widely used model of Parkinson’s disease). We found that MPP+ predominantly induced non-apoptotic death of neuronally differentiated SH-SY5Y cells. This cell death was strongly inhibited by necrostatin-1 (Nec-1), a necroptosis inhibitor, and by an indole-containing compound (3,3′-diindolylmethane: DIM). However, it occurred independently of receptor-interacting serine/threonine-protein kinase 1/3 (RIP1/RIP3), indicating that this form of cell death was not necroptosis. MPP+-induced cell death was also inhibited by several inhibitors of ferroptosis, including ferrostatin-1 (Fer-1). Although MPP+-induced death and ferroptosis shared some features, such as occurrence of lipid peroxidation and inhibition by Fer-1, MPP+-induced death seemed to be distinct from ferroptosis because MPP+-induced death (but not ferroptosis) was inhibited by Nec-1, was independent of p53, and was accompanied by ATP depletion and mitochondrial swelling. Further investigation of MPP+-induced non-apoptotic cell death may be useful for understanding the mechanisms of neuronal loss and for treatment of neurodegenerative diseases such as Parkinson’s disease. PMID:28250973

Cordycepin-induced apoptosis and autophagy in breast cancer cells are independent of the estrogen receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Sunga; Lim, Mi-Hee; Kim, Ki Mo

2011-12-15

Cordycepin (3-deoxyadenosine), found in Cordyceps spp., has been known to have many therapeutic effects including immunomodulatory, anti-inflammatory, antimicrobial, and anti-aging effects. Moreover, anti-tumor and anti-metastatic effects of cordycepin have been reported, but the mechanism causing cancer cell death is poorly characterized. The present study was designed to investigate whether the mechanisms of cordycepin-induced cell death were associated with estrogen receptor in breast cancer cells. Exposure of both MDA-MB-231 and MCF-7 human breast cancer cells to cordycepin resulted in dose-responsive inhibition of cell growth and reduction in cell viability. The cordycepin-induced cell death in MDA-MB-231 cells was associated with several specificmore » features of the mitochondria-mediated apoptotic pathway, which was confirmed by DNA fragmentation, TUNEL, and biochemical assays. Cordycepin also caused a dose-dependent increase in mitochondrial translocation of Bax, triggering cytosolic release of cytochrome c and activation of caspases-9 and -3. Interestingly, MCF-7 cells showed autophagy-associated cell death, as observed by the detection of an autophagosome-specific protein and large membranous vacuole ultrastructure morphology in the cytoplasm. Cordycepin-induced autophagic cell death has applications in treating MCF-7 cells with apoptotic defects, irrespective of the ER response. Although autophagy has a survival function in tumorigenesis of some cancer cells, autophagy may be important for cordycepin-induced MCF-7 cell death. In conclusion, the results of our study demonstrate that cordycepin effectively kills MDA-MB-231 and MCF-7 human breast cancer cell lines in culture. Hence, further studies should be conducted to determine whether cordycepin will be a clinically useful, ER-independent, chemotherapeutic agent for human breast cancer. -- Highlights: Black-Right-Pointing-Pointer We studied the mechanism which cordycepin-induced cell death

Role of the immune modulator programmed cell death-1 during development and apoptosis of mouse retinal ganglion cells

PubMed Central

Chen, Ling; Sham, Caroline W.; Chan, Ann M.; Francisco, Loise M.; Wu, Yin; Mareninov, Sergey; Sharpe, Arlene H.; Freeman, Gordon J.; Yang, Xian-Jie; Braun, Jonathan; Gordon, Lynn K.

2011-01-01

PURPOSE Mammalian programmed cell death-1 (PD-1) is a membrane-associated receptor regulating the balance between T cell activation, tolerance and immunopathology, however its role in neurons has not yet been defined. We investigate the hypothesis that PD-1 signaling actively promotes retinal ganglion cell (RGC) death within the developing mouse retina. METHODS Mature retinal cell types expressing PD-1 were identified by immunofluorescence staining of vertical retina sections; developmental expression was localized by immunostaining and quantified by Western analysis. PD-1 involvement in developmental RGC survival was assessed in vitro using retina explants and in vivo using PD-1 knockout mice. PD-1 ligand gene expression was detected by RT-PCR. RESULTS PD-1 is expressed in most adult RGCs, and undergoes dynamic upregulation during the early postnatal window of retinal cell maturation and physiological programmed cell death (PCD). In vitro blockade of PD-1 signaling during this time selectively increases survival of RGCs. Furthermore, PD-1 deficient mice show a selective increase in RGC number in the neonatal retina at the peak of developmental RGC death. Lastly, throughout postnatal retina maturation, we find gene expression of both immune PD-1 ligand genes, PD-L1 and PD-L2. CONCLUSIONS These findings collectively support a novel role for a PD-1-mediated signaling pathway in developmental PCD during postnatal RGC maturation. PMID:19420345

A mechanistic study on the effect of dexamethasone in moderating cell death in Chinese Hamster Ovary cell cultures.

PubMed

Jing, Ying; Qian, Yueming; Ghandi, Mahmoud; He, Aiqing; Borys, Michael C; Pan, Shih-Hsie; Li, Zheng Jian

2012-01-01

Dexamethasone (DEX) was previously shown (Jing et al., Biotechnol Bioeng. 2010;107:488-496) to play a dual role in increasing sialylation of recombinant glycoproteins produced by Chinese Hamster Ovary (CHO) cells. DEX addition increased sialic acid levels of a recombinant fusion protein through increased expression of α2,3-sialyltransferase and β1,4-galactosyltransferase, but also decreased the sialidase-mediated, extracellular degradation of sialic acid through slowing cell death at the end of the culture period. This study examines the underlying mechanism for this cytoprotective action by studying the transcriptional response of the CHO cell genome upon DEX treatment using DNA microarrays and gene ontology term analysis. Many of those genes showing a significant transcriptional response were associated with the regulation of programmed cell death. The gene with the highest change in expression level, as validated by Quantitative PCR assays with TaqMan® probes and confirmed by Western Blot analysis, was the antiapoptotic gene Tsc22d3, also referred to as GILZ (glucocorticoid-induced leucine zipper). The pathway by which DEX suppressed cell death towards the end of the culture period was also confirmed by showing involvement of glucocorticoid receptors and GILZ through studies using the glucocorticoid antagonist mifepristone (RU-486). These findings advance the understanding of the mechanism by which DEX suppresses cell death in CHO cells and provide a rationale for the application of glucocorticoids in CHO cell culture processes. Copyright © 2011 American Institute of Chemical Engineers (AIChE).

Calmodulin protects cells from death under normal growth conditions and mitogenic starvation but plays a mediating role in cell death upon B-cell receptor stimulation

PubMed Central

Schmalzigaug, Robert; Ye, Qunrui; Berchtold, Martin W

2001-01-01

Calmodulin (CaM) is the main intracellular Ca2+ sensor protein responsible for mediating Ca2+ triggered processes. Chicken DT40 lymphoma B cells express CaM from the two genes, CaMI and CaMII. Here we report the phenotypes of DT40 cells with the CaMII gene knocked out. The disruption of the CaMII gene causes the intracellular CaM level to decrease by 60%. CaMII−/− cells grow more slowly and die more frequently as compared to wild type (wt) cells but do not exhibit significant differences in their cell cycle profile. Both phenotypes are more pronounced at reduced serum concentrations. Upon stimulation of the B-cell receptor (BCR), the resting Ca2+ levels remain elevated after the initial transient in CaMII−/− cells. Despite higher Ca2+ resting levels, the CaMII−/− cells are partially protected from BCR induced apoptosis indicating that CaM plays a dual role in apoptotic processes. PMID:11454062

A new cannabinoid CB2 receptor agonist HU-910 attenuates oxidative stress, inflammation and cell death associated with hepatic ischaemia/reperfusion injury

PubMed Central

Horváth, Bėla; Magid, Lital; Mukhopadhyay, Partha; Bátkai, Sándor; Rajesh, Mohanraj; Park, Ogyi; Tanchian, Galin; Gao, Rachel Y; Goodfellow, Catherine E; Glass, Michelle; Mechoulam, Raphael; Pacher, Pál

2012-01-01

BACKGROUND AND PURPOSE Cannabinoid CB2 receptor activation has been reported to attenuate myocardial, cerebral and hepatic ischaemia-reperfusion (I/R) injury. EXPERIMENTAL APPROACH We have investigated the effects of a novel CB2 receptor agonist ((1S,4R)-2-(2,6-dimethoxy-4-(2-methyloctan-2-yl)phenyl)-7,7-dimethylbicyclo[2.2.1]hept-2-en-1-yl)methanol (HU-910) on liver injury induced by 1 h of ischaemia followed by 2, 6 or 24 h of reperfusion, using a well-established mouse model of segmental hepatic I/R. KEY RESULTS Displacement of [3H]CP55940 by HU-910 from specific binding sites in CHO cell membranes transfected with human CB2 or CB1 receptors (hCB1/2) yielded Ki values of 6 nM and 1.4 µM respectively. HU-910 inhibited forskolin-stimulated cyclic AMP production by hCB2 CHO cells (EC50= 162 nM) and yielded EC50 of 26.4 nM in [35S]GTPγS binding assays using hCB2 expressing CHO membranes. HU-910 given before ischaemia significantly attenuated levels of I/R-induced hepatic pro-inflammatory chemokines (CCL3 and CXCL2), TNF-α, inter-cellular adhesion molecule-1, neutrophil infiltration, oxidative stress and cell death. Some of the beneficial effect of HU-910 also persisted when given at the beginning of the reperfusion or 1 h after the ischaemic episode. Furthermore, HU-910 attenuated the bacterial endotoxin-triggered TNF-α production in isolated Kupffer cells and expression of adhesion molecules in primary human liver sinusoidal endothelial cells stimulated with TNF-α. Pretreatment with a CB2 receptor antagonist attenuated the protective effects of HU-910, while pretreatment with a CB1 antagonist tended to enhance them. CONCLUSION AND IMPLICATIONS HU-910 is a potent CB2 receptor agonist which may exert protective effects in various diseases associated with inflammation and tissue injury. LINKED ARTICLES This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph

A new cannabinoid CB2 receptor agonist HU-910 attenuates oxidative stress, inflammation and cell death associated with hepatic ischaemia/reperfusion injury.

PubMed

Horváth, Bėla; Magid, Lital; Mukhopadhyay, Partha; Bátkai, Sándor; Rajesh, Mohanraj; Park, Ogyi; Tanchian, Galin; Gao, Rachel Y; Goodfellow, Catherine E; Glass, Michelle; Mechoulam, Raphael; Pacher, Pál

2012-04-01

Cannabinoid CB(2) receptor activation has been reported to attenuate myocardial, cerebral and hepatic ischaemia-reperfusion (I/R) injury. We have investigated the effects of a novel CB(2) receptor agonist ((1S,4R)-2-(2,6-dimethoxy-4-(2-methyloctan-2-yl)phenyl)-7,7-dimethylbicyclo[2.2.1]hept-2-en-1-yl)methanol (HU-910) on liver injury induced by 1 h of ischaemia followed by 2, 6 or 24 h of reperfusion, using a well-established mouse model of segmental hepatic I/R. Displacement of [(3) H]CP55940 by HU-910 from specific binding sites in CHO cell membranes transfected with human CB(2) or CB(1) receptors (hCB(1/2) ) yielded K(i) values of 6 nM and 1.4 µM respectively. HU-910 inhibited forskolin-stimulated cyclic AMP production by hCB(2) CHO cells (EC(50) = 162 nM) and yielded EC(50) of 26.4 nM in [(35) S]GTPγS binding assays using hCB(2) expressing CHO membranes. HU-910 given before ischaemia significantly attenuated levels of I/R-induced hepatic pro-inflammatory chemokines (CCL3 and CXCL2), TNF-α, inter-cellular adhesion molecule-1, neutrophil infiltration, oxidative stress and cell death. Some of the beneficial effect of HU-910 also persisted when given at the beginning of the reperfusion or 1 h after the ischaemic episode. Furthermore, HU-910 attenuated the bacterial endotoxin-triggered TNF-α production in isolated Kupffer cells and expression of adhesion molecules in primary human liver sinusoidal endothelial cells stimulated with TNF-α. Pretreatment with a CB(2) receptor antagonist attenuated the protective effects of HU-910, while pretreatment with a CB(1) antagonist tended to enhance them. HU-910 is a potent CB(2) receptor agonist which may exert protective effects in various diseases associated with inflammation and tissue injury. This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and

Delayed innocent bystander cell death following hypoxia in Caenorhabditis elegans

PubMed Central

Sun, C-L; Kim, E; Crowder, C M

2014-01-01

After hypoxia, cells may die immediately or have a protracted course, living or dying depending on an incompletely understood set of cell autonomous and nonautonomous factors. In stroke, for example, some neurons are thought to die from direct hypoxic injury by cell autonomous primary mechanisms, whereas other so called innocent bystander neurons die from factors released from the primarily injured cells. A major limitation in identifying these factors is the inability of current in vivo models to selectively target a set of cells for hypoxic injury so that the primarily injured cells and the innocent bystanders are clearly delineated. In order to develop such a model, we generated transgenic Caenorhabditis elegans strains where 2–3% of somatic cells were made selectively sensitive to hypoxia. This was accomplished by cell type-specific wild-type rescue in either pharyngeal myocytes or GABAergic neurons of a hypoxia resistance-producing translation factor mutation. Surprisingly, hypoxic targeting of these relatively small subsets of non-essential cells produced widespread innocent bystander cell injury, behavioral dysfunction and eventual organismal death. The hypoxic injury phenotypes of the myocyte or neuron sensitized strains were virtually identical. Using this model, we show that the C. elegans insulin receptor/FOXO transcription factor pathway improves survival when activated only after hypoxic injury and blocks innocent bystander death. PMID:24317200

Detection of Inflammasome Activation and Pyroptotic Cell Death in Murine Bone Marrow-derived Macrophages.

PubMed

den Hartigh, Andreas B; Fink, Susan L

2018-05-21

Inflammasomes are innate immune signaling platforms that are required for the successful control of many pathogenic organisms, but also promote inflammatory and autoinflammatory diseases. Inflammasomes are activated by cytosolic pattern recognition receptors, including members of the NOD-like receptor (NLR) family. These receptors oligomerize upon the detection of microbial or damage-associated stimuli. Subsequent recruitment of the adaptor protein ASC forms a microscopically visible inflammasome complex, which activates caspase-1 through proximity-induced auto-activation. Following the activation, caspase-1 cleaves pro-IL-1β and pro-IL-18, leading to the activation and secretion of these pro-inflammatory cytokines. Caspase-1 also mediates the inflammatory form of cell death termed pyroptosis, which features the loss of membrane integrity and cell lysis. Caspase-1 cleaves gasdermin D, releasing the N-terminal fragment which forms plasma membrane pores, leading to osmotic lysis. In vitro, the activation of caspase-1 can be determined by labeling bone marrow-derived macrophages with the caspase-1 activity probe FAM-YVAD-FMK and by labeling the cells with antibodies against the adaptor protein ASC. This technique allows the identification of inflammasome formation and caspase-1 activation in individual cells using fluorescence microscopy. Pyroptotic cell death can be detected by measuring the release of cytosolic lactate dehydrogenase into the medium. This procedure is simple, cost effective and performed in a 96-well plate format, allowing adaptation for screening. In this manuscript, we show that activation of the NLRP3 inflammasome by nigericin leads to the co-localization of the adaptor protein ASC and active caspase-1, leading to pyroptosis.

Molecular mechanisms of programmed cell death-1 dependent T cell suppression: relevance for immunotherapy

PubMed Central

Zuazo, Miren; Gato-Cañas, Maria; Llorente, Noelia; Ibañez-Vea, María; Arasanz, Hugo

2017-01-01

Programmed cell death-1 (PD1) has become a significant target for cancer immunotherapy. PD1 and its receptor programmed cell death 1 ligand 1 (PDL1) are key regulatory physiological immune checkpoints that maintain self-tolerance in the organism by regulating the degree of activation of T and B cells amongst other immune cell types. However, cancer cells take advantage of these immunosuppressive regulatory mechanisms to escape T and B cell-mediated immunity. PD1 engagement on T cells by PDL1 on the surface of cancer cells dramatically interferes with T cell activation and the acquisition of effector capacities. Interestingly, PD1-targeted therapies have demonstrated to be highly effective in rescuing T cell anti-tumor effector functions. Amongst these the use of anti-PD1/PDL1 monoclonal antibodies are particularly efficacious in human therapies. Furthermore, clinical findings with PD1/PDL1 blockers over several cancer types demonstrate clinical benefit. Despite the successful results, the molecular mechanisms by which PD1-targeted therapies rescue T cell functions still remain elusive. Therefore, it is a key issue to uncover the molecular pathways by which these therapies exert its function in T cells. A profound knowledge of PDL1/PD1 mechanisms will surely uncover a new array of targets susceptible of therapeutic intervention. Here, we provide an overview of the molecular events underlying PD1-dependent T cell suppression in cancer. PMID:29114543

Proneurotrophin-3 promotes cell cycle withdrawal of developing cerebellar granule cell progenitors via the p75 neurotrophin receptor.

PubMed

Zanin, Juan Pablo; Abercrombie, Elizabeth; Friedman, Wilma J

2016-07-19

Cerebellar granule cell progenitors (GCP) proliferate extensively in the external granule layer (EGL) of the developing cerebellum prior to differentiating and migrating. Mechanisms that regulate the appropriate timing of cell cycle withdrawal of these neuronal progenitors during brain development are not well defined. The p75 neurotrophin receptor (p75(NTR)) is highly expressed in the proliferating GCPs, but is downregulated once the cells leave the cell cycle. This receptor has primarily been characterized as a death receptor for its ability to induce neuronal apoptosis following injury. Here we demonstrate a novel function for p75(NTR) in regulating proper cell cycle exit of neuronal progenitors in the developing rat and mouse EGL, which is stimulated by proNT3. In the absence of p75(NTR), GCPs continue to proliferate beyond their normal period, resulting in a larger cerebellum that persists into adulthood, with consequent motor deficits.

Programmed Cell Death During Caenorhabditis elegans Development

PubMed Central

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

2016-01-01

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

Bubbling cell death: A hot air balloon released from the nucleus in the cold.

PubMed

Chang, Nan-Shan

2016-06-01

Cell death emanating from the nucleus is largely unknown. In our recent study, we determined that when temperature is lowered in the surrounding environment, apoptosis stops and bubbling cell death (BCD) occurs. The study concerns the severity of frostbite. When exposed to severe cold and strong ultraviolet (UV) irradiation, people may suffer serious damages to the skin and internal organs. This ultimately leads to limb amputations, organ failure, and death. BCD is defined as "formation of a single bubble from the nucleus per cell and release of this swelling bubble from the cell surface to extracellular space that causes cell death." When cells are subjected to UV irradiation and/or brief cold shock (4℃ for 5 min) and then incubated at room temperature or 4℃ for time-lapse microscopy, each cell releases an enlarging nuclear gas bubble containing nitric oxide. Certain cells may simultaneously eject hundreds or thousands of exosome-like particles. Unlike apoptosis, no phosphatidylserine flip-over, mitochondrial apoptosis, damage to Golgi complex, and chromosomal DNA fragmentation are shown in BCD. When the temperature is increased back at 37℃, bubble formation stops and apoptosis restarts. Mechanistically, proapoptotic WW domain-containing oxidoreductase and p53 block the protective TNF receptor adaptor factor 2 that allows nitric oxide synthase 2 to synthesize nitric oxide and bubble formation. In this mini-review, updated knowledge in cell death and the proposed molecular mechanism for BCD are provided. © 2016 by the Society for Experimental Biology and Medicine.

A Novel Bcl-x Isoform Connected to the T Cell Receptor Regulates Apoptosis in T Cells

PubMed Central

Yang, Xiao-Feng; Weber, Georg F.

2014-01-01

Summary We define a novel Bcl-x isoform, Bcl-xγ, that is generated by alternative splicing and characterized by a unique 47 amino acid C-terminus. Bcl-xγ is expressed primarily in thymocytes, where it may depend on an interaction between the TCR and host MHC products, and in mature T cells, where its expression is associated with ligation of the T cell receptor. Overexpression of Bcl-xγ in T cells inhibits activation-induced apoptosis; inhibition of Bcl-xγ, after stable expression of Bcl-xγ antisense cDNA, enhances activation-induced apoptosis. In contrast to other Bcl-x isoforms, cells that fail to express Bcl-xγ after CD3 ligation undergo programmed cell death, while activated T cells that express Bcl-xγ are spared. Identification of Bcl-xγ helps provide amolecular explanation of T cell activation and death after antigen engagement. PMID:9390687

Identification of the Calmodulin-Binding Domains of Fas Death Receptor

PubMed Central

Chang, Bliss J.; Samal, Alexandra B.; Vlach, Jiri; Fernandez, Timothy F.; Brooke, Dewey; Prevelige, Peter E.; Saad, Jamil S.

2016-01-01

The extrinsic apoptotic pathway is initiated by binding of a Fas ligand to the ectodomain of the surface death receptor Fas protein. Subsequently, the intracellular death domain of Fas (FasDD) and that of the Fas-associated protein (FADD) interact to form the core of the death-inducing signaling complex (DISC), a crucial step for activation of caspases that induce cell death. Previous studies have shown that calmodulin (CaM) is recruited into the DISC in cholangiocarcinoma cells and specifically interacts with FasDD to regulate the apoptotic/survival signaling pathway. Inhibition of CaM activity in DISC stimulates apoptosis significantly. We have recently shown that CaM forms a ternary complex with FasDD (2:1 CaM:FasDD). However, the molecular mechanism by which CaM binds to two distinct FasDD motifs is not fully understood. Here, we employed mass spectrometry, nuclear magnetic resonance (NMR), biophysical, and biochemical methods to identify the binding regions of FasDD and provide a molecular basis for the role of CaM in Fas–mediated apoptosis. Proteolytic digestion and mass spectrometry data revealed that peptides spanning residues 209–239 (Fas-Pep1) and 251–288 (Fas-Pep2) constitute the two CaM-binding regions of FasDD. To determine the molecular mechanism of interaction, we have characterized the binding of recombinant/synthetic Fas-Pep1 and Fas-Pep2 peptides with CaM. Our data show that both peptides engage the N- and C-terminal lobes of CaM simultaneously. Binding of Fas-Pep1 to CaM is entropically driven while that of Fas-Pep2 to CaM is enthalpically driven, indicating that a combination of electrostatic and hydrophobic forces contribute to the stabilization of the FasDD–CaM complex. Our data suggest that because Fas-Pep1 and Fas-Pep2 are involved in extensive intermolecular contacts with the death domain of FADD, binding of CaM to these regions may hinder its ability to bind to FADD, thus greatly inhibiting the initiation of apoptotic signaling

Schizophrenia, dissociative anaesthesia and near-death experience; three events meeting at the NMDA receptor.

PubMed

Bonta, Iván L

2004-01-01

The three events, viz. schizophrenia, dissociative anaesthesia and Near-Death Experience, despite their seemingly unrelated manifestation to each other, have nevertheless similar functional basis. All three events are linked to the glutamate sensitive N-methyl-D-aspartate (NMDA) receptor complex, which serves as their common functional denominator. Arguments and speculations are presented in favor of the view that, the three events might be considered as functional models of each other. Antagonism to the recognition NMDA-site of the receptor induces dissociative anaesthesia and precipitates Near-Death Experience. Agonist reinforcement at the modulatory glycine-site of the receptor counteracts negative symptoms of schizophrenia. Both types of challenges towards the receptor are compatible with a glutamate deficiency concept which underlies the meeting of the three events at the NMDA receptor.

Methanolic extract of white asparagus shoots activates TRAIL apoptotic death pathway in human cancer cells and inhibits colon carcinogenesis in a preclinical model

PubMed Central

BOUSSEROUEL, SOUAD; LE GRANDOIS, JULIE; GOSSÉ, FRANCINE; WERNER, DALAL; BARTH, STEPHAN W.; MARCHIONI, ERIC; MARESCAUX, JACQUES; RAUL, FRANCIS

2013-01-01

Shoots of white asparagus are a popular vegetable dish, known to be rich in many bioactive phytochemicals reported to possess antioxidant, and anti-inflammatory and antitumor activities. We evaluated the anticancer mechanisms of a methanolic extract of Asparagus officinalis L. shoots (Asp) on human colon carcinoma cells (SW480) and their derived metastatic cells (SW620), and Asp chemopreventive properties were also assessed in a model of colon carcinogenesis. SW480 and SW620 cell proliferation was inhibited by 80% after exposure to Asp (80 μg/ml). We demonstrated that Asp induced cell death through the activation of TRAIL DR4/DR5 death receptors leading to the activation of caspase-8 and caspase-3 and to cell apoptosis. By specific blocking agents of DR4/DR5 receptors we were able to prevent Asp-triggered cell death confirming the key role of DR4/DR5 receptors. We found also that Asp (80 μg/ml) was able to potentiate the effects of the cytokine TRAIL on cell death even in the TRAIL-resistant metastatic SW620 cells. Colon carcinogenesis was initiated in Wistar rats by intraperitoneal injections of azoxymethane (AOM), once a week for two weeks. One week after (post-initiation) rats received daily Asp (0.01%, 14 mg/kg body weight) in drinking water. After 7 weeks of Asp-treatment the colon of rats exhibited a 50% reduction of the number of preneoplastic lesions (aberrant crypt foci). In addition Asp induced inhibition of several pro-inflammatory mediators, in association with an increased expression of host-defense mediators. In the colonic mucosa of Asp-treated rats we also confirmed the pro-apoptotic effects observed in vitro including the activation of the TRAIL death-receptor signaling pathway. Taken together, our data highlight the chemopreventive effects of Asp on colon carcinogenesis and its ability to promote normal cellular homeostasis. PMID:23754197

Folate receptor 1 (FOLR1) targeted chimeric antigen receptor (CAR) T cells for the treatment of gastric cancer

PubMed Central

Pyo, Suhkneung; Kang, Chung Hyo; Lee, Chong Ock; Lee, Heung Kyoung; Choi, Sang Un; Park, Chi Hoon

2018-01-01

Gastric cancer is a malignancy that has a high mortality rate. Although progress has been made in the treatment of gastric cancer, many patients experience cancer recurrence and metastasis. Folate receptor 1 (FOLR1) is overexpressed on the cell surface in over one-third of gastric cancer patients, but rarely is expressed in normal tissue. This makes FOLR1 a potential target for chimeric antigen receptor (CAR) T cell immunotherapy, although the function of FOLR1 has not been elucidated. CAR are engineered fusion receptor composed of an antigen recognition region and signaling domains. T cells expressing CAR have specific activation and cytotoxic effects against cancer cells containing the target antigen. In this study, we generated a CAR that targets FOLR1 composed of a single-chain variable fragment (scFv) of FOLR1 antibody and signaling domains consisting of CD28 and CD3ζ. Both FOLR1-CAR KHYG-1, a natural killer cell line, and FOLR1-CAR T cells recognized FOLR1-positive gastric cancer cells in a MHC-independent manner and induced secretion of various cytokines and caused cell death. Conclusively, this is the first study to demonstrate that CAR KHYG-1/T cells targeting FOLR1 are effective against FOLR1-positive gastric cancer cells. PMID:29874279

Chaetocin induces endoplasmic reticulum stress response and leads to death receptor 5-dependent apoptosis in human non-small cell lung cancer cells.

PubMed

Liu, Xianfang; Guo, Sen; Liu, Xiangguo; Su, Ling

2015-11-01

Epigenetic abnormalities are associated with non-small cell lung cancer (NSCLC) initiation and progression. Epigenetic drugs are being studied and in clinical trials. However, the molecular mechanism underlying the apoptosis by the epigenetic agents remains unclear. SUV39H1 is an important methyl-transferase for lysine 9 on histone H3 and usually related to gene transcriptional suppression, and chaetocin acts as the inhibitor of SUV39H1. We demonstrated here that chaetocin effectively suppressed the growth of multiple lung cancer cells through inducing apoptosis in a death receptor 5 (DR5)-dependent manner. Chaetocin treatment activated endoplasmic reticulum (ER) stress which gave rise to the up-regulation of ATF3 and CHOP. Furthermore, ATF3 and CHOP contributed to the induction of DR5 and subsequent apoptosis. When SUV39H1 was silenced with siRNA, the expression of ATF3, CHOP and DR5 was elevated. Thereafter, knockdown of SUV39H1 induced apoptosis in NSCLC cells. In summary, chaetocin pharmacologically inhibits the activity of SUV39H1 which provokes ER stress and results in up-regulation of ATF3 and CHOP, leading to DR5-dependent apoptosis eventually. These findings provide a novel interpretation on the anti-neoplastic activity of epigenetic drugs as a new therapeutic approach in NSCLC.

Differential participation of angiotensin II type 1 and 2 receptors in the regulation of cardiac cell death triggered by angiotensin II.

PubMed

Aránguiz-Urroz, Pablo; Soto, Dagoberto; Contreras, Ariel; Troncoso, Rodrigo; Chiong, Mario; Montenegro, José; Venegas, Daniel; Smolic, Christian; Ayala, Pedro; Thomas, Walter G; Lavandero, Sergio; Díaz-Araya, Guillermo

2009-05-01

The Angiotensin II (Ang II) type 1 (AT(1)R) and type 2 (AT(2)R) receptors are increased in the heart following myocardial infarction and dilated cardiomyopathy, yet their contribution at a cellular level to compensation and/or failure remains controversial. We ectopically expressed AT(1)R and AT(2)R in cultured adult rat cardiomyocytes and cardiac fibroblasts to investigate Ang II-mediated cardiomyocyte hypertrophy and cardiac cell viability. In adult rat cardiomyocytes, Ang II did not induce hypertrophy via the AT(1)R, and no effect of Ang II on cell viability was observed following AT(1)R or AT(2)R expression. In adult rat cardiac fibroblasts, Ang II stimulated cell death by apoptosis via the AT(1)R (but not the AT(2)R), which required the presence of extracellular calcium, and induced a rapid dissipation of mitochondrial membrane potential, which was significant from 8 h. We conclude that Ang II/AT(1)R triggers apoptosis in adult rat cardiac fibroblasts, which is dependent on Ca2+ influx.

Signaling pathways that regulate life and cell death: evolution of apoptosis in the context of self-defense.

PubMed

Muñoz-Pinedo, Cristina

2012-01-01

Programmed Cell Death is essential for the life cycle of many organisms. Cell death in multicellular organisms can occur as a consequence of massive damage (necrosis) or in a controlled form, through engagement of diverse biochemical programs. The best well known form of programmed cell death is apoptosis. Apoptosis occurs in animals as a consequence of a variety of stimuli including stress and social signals and it plays essential roles in morphogenesis and immune defense. The machinery of apoptosis is well conserved among animals and it is composed of caspases (the proteases which execute cell death), adapter proteins (caspase activators), Bcl-2 family proteins and Inhibitor of Apoptosis Proteins (IAPs). We will describe in this chapter the main apoptotic pathways in animals: the extrinsic (death receptor-mediated), the intrinsic/mitochondrial and the Granzyme B pathway. Other forms of non-apoptotic Programmed Cell Death which occur in animals will also be discussed. We will summarize the current knowledge about apoptotic-like and other forms of cell death in other organisms such as plants and protists.Additionally, we will discuss the hypothesis that apoptosis originated as part of a host defense mechanism. We will explore the similarities between the protein complexes which mediate apoptosis (apoptosomes) and complexes involved in immunity: inflammasomes. Additional functions of apoptotic proteins related to immune function will be summarized, in an effort to explore the evolutionary origins of cell death.

Cocaine-Mediated Autophagy in Astrocytes Involves Sigma 1 Receptor, PI3K, mTOR, Atg5/7, Beclin-1 and Induces Type II Programed Cell Death.

PubMed

Cao, Lu; Walker, Mary P; Vaidya, Naveen K; Fu, Mingui; Kumar, Santosh; Kumar, Anil

2016-09-01

Cocaine, a commonly used drug of abuse, has been shown to cause neuropathological dysfunction and damage in the human brain. However, the role of autophagy in this process is not defined. Autophagy, generally protective in nature, can also be destructive leading to autophagic cell death. This study was designed to investigate whether cocaine induces autophagy in the cells of CNS origin. We employed astrocyte, the most abundant cell in the CNS, to define the effects of cocaine on autophagy. We measured levels of the autophagic marker protein LC3II in SVGA astrocytes after exposure with cocaine. The results showed that cocaine caused an increase in LC3II level in a dose- and time-dependent manner, with the peak observed at 1 mM cocaine after 6-h exposure. This result was also confirmed by detecting LC3II in SVGA astrocytes using confocal microscopy and transmission electron microscopy. Next, we sought to explore the mechanism by which cocaine induces the autophagic response. We found that cocaine-induced autophagy was mediated by sigma 1 receptor, and autophagy signaling proteins p-mTOR, Atg5, Atg7, and p-Bcl-2/Beclin-1 were also involved, and this was confirmed by using selective inhibitors and small interfering RNAs (siRNAs). In addition, we found that chronic treatment with cocaine resulted in cell death, which is caspase-3 independent and can be ameliorated by autophagy inhibitor. Therefore, this study demonstrated that cocaine induces autophagy in astrocytes and is associated with autophagic cell death.

Cocaine-mediated autophagy in astrocytes involves sigma 1 receptor, PI3K, m-TOR, Atg5/7, Beclin-1 and induces Type II programed cell death

PubMed Central

Cao, Lu; Walker, Mary P; Vaidya, Naveen K; Fu, Mingui; Kumar, Santosh; Kumar, Anil

2015-01-01

Cocaine, a commonly used drug of abuse, has been shown to cause neuropathological dysfunction and damage in the human brain. However, the role of autophagy in this process is not defined. Autophagy generally protective in nature, can also be destructive leading to autophagic cell death. This study was designed to investigate whether cocaine induces autophagy in the cells of CNS origin. We employed astrocyte, the most abundant cell in the CNS, to define the effects of cocaine on autophagy. We measured levels of the autophagic marker protein LC3II in SVGA astrocytes after exposure with cocaine. The results showed that cocaine caused an increase in LC3II level in a dose- and time-dependent manner, with the peak observed at 1 mM cocaine after 6 hours exposure. This result was also confirmed by detecting LC3II in SVGA astrocytes using confocal microscopy and transmission electron microscopy. Next, we sought to explore the mechanism by which cocaine induces the autophagic response. We found that cocaine-induced autophagy was mediated by sigma 1 receptor, and autophagy signaling proteins p-mTOR, Atg5, Atg7 and p-Bcl-2/Beclin-1 were also involved and this was confirmed by using selective inhibitors and siRNAs. In addition, we found that chronic treatment with cocaine resulted in cell death, which is caspase-3 independent, and can be ameliorated by autophagy inhibitor. Therefore, this study demonstrated that cocaine induces autophagy in astrocytes and is associated with autophagic cell death. PMID:26243186

[Methuosis: a novel type of cell death].

PubMed

Cai, Hongbing; Liu, Jinkun; Fan, Qin; Li, Xin

2013-12-01

Cell death is a major physiological or pathological phenomenon in life activities. The classic forms of cell death include apoptosis, necrosis, and autophagy. Recently, a novel type of cell death has been observed and termed as methuosis, in which excessive stimuli can induce cytoplasmic uptake and accumulation of small bubbles that gradually merge into giant vacuoles, eventually leading to decreased cellular metabolic activity, cell membrane rupture and cell death. In this article, we describe the nomenclature, morphological characteristics and underlying mechanisms of methuosis, compare methuosis with autophagy, oncosis and paraptosis, and review the related researches.

Bacillus thuringiensis toxins trigger receptor shedding from gypsy moth midgut cells

Treesearch

Algimantas P. Valaitis

2007-01-01

The mechanism of action of the Cry1 insecticidal proteins produced by Bacillus thuringiensis (Bt) begins with the processing of these proteins in the larval gut. After proteolytic activation, the Bt toxins bind to specific midgut receptors and insert into the membrane of the gut epithelial cells, causing insect death.

Morphological classification of plant cell deaths.

PubMed

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

2011-08-01

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.

Cannabinoid Receptor Type 1 Agonist ACEA Protects Neurons from Death and Attenuates Endoplasmic Reticulum Stress-Related Apoptotic Pathway Signaling.

PubMed

Vrechi, Talita A; Crunfli, Fernanda; Costa, Andressa P; Torrão, Andréa S

2018-05-01

Neurodegeneration is the result of progressive destruction of neurons in the central nervous system, with unknown causes and pathological mechanisms not yet fully elucidated. Several factors contribute to neurodegenerative processes, including neuroinflammation, accumulation of neurotoxic factors, and misfolded proteins in the lumen of the endoplasmic reticulum (ER). Endocannabinoid signaling has been pointed out as an important modulatory system in several neurodegeneration-related processes, inhibiting the inflammatory response and increasing neuronal survival. Thus, we investigated the presumptive protective effect of the selective cannabinoid type 1 (CB1) receptor agonist arachidonyl-2'-chloroethylamide (ACEA) against inflammatory (lipopolysaccharide, LPS) and ER stress (tunicamycin) stimuli in an in vitro neuronal model (Neuro-2a neuroblastoma cells). Cell viability analysis revealed that ACEA was able to protect against cell death induced by LPS and tunicamycin. This neuroprotective effect occurs via the CB1 receptor in the inflammation process and via the transient receptor potential of vanilloid type-1 (TRPV1) channel in ER stress. Furthermore, the immunoblotting analyses indicated that the neuroprotective effect of ACEA seems to involve the modulation of eukaryotic initiation factor 2 (eIF2α), transcription factor C/EBP homologous protein (CHOP), and caspase 12, as well as the survival/death p44/42 MAPK, ERK1/2-related signaling pathways. Together, these data suggest that the endocannabinoid system is a potential therapeutic target in neurodegenerative processes, especially in ER-related neurodegenerative diseases.

Prognostic Value of Soluble Death Receptor Ligands in Patients with Transitional Cell Carcinoma of Bladder.

PubMed

Ben Bahria-Sediki, Islem; Chebil, Mohamed; Sampaio, Carla; Martel-Frachet, Véronique; Cherif, Mohamed; Zermani, Rachida; Rammeh, Soumaya; Ben Ammar Gaaied, Amel; Bettaieb, Ali

2018-05-02

The activation of Fas/Fas ligand (FasL) and DR4-DR5/tumor necrosis factor-related-apoptosis-inducing ligand (TRAIL) pathways in cancer cells triggers apoptosis. The objective of this study was to investigate the prognostic value of soluble FasL (sFasL) and soluble (sTRAIL) in the serum of patients with bladder cancer. The sFasL and sTRAIL levels in the sera of patients with bladder cancer or healthy donors were determined using the enzyme-linked immunosorbent assay. Micro-culture tetrazolium viability assay and Western blot were used to analyze cell cytotoxicity and death receptors protein expression respectively. Whether no difference in sTRAIL levels was seen between patients and controls, the level of sFasL was higher in patients than that in healthy donors. According to, sFasL level was the highest in the serum of patients with superficial stage or low- and medium-grade cancer. Moreover, sFasL in patients with superficial noninvasive bladder tumors or low- and medium-grade cancers was higher than that in patients with invasive carcinomas and high-grade cancers. Patients with high levels of sFasL survive longer than those with low levels, probably related to the cytotoxic potential of FasL preserved in its soluble form. The data suggest that monitoring the level of sFasL and its cytotoxic activity could be a prognostic marker in the follow-up of patients with bladder cancer. © 2018 S. Karger AG, Basel.

Mutation in Fas Ligand Impairs Maturation of Thymocytes Bearing Moderate Affinity T Cell Receptors

PubMed Central

Boursalian, Tamar E.; Fink, Pamela J.

2003-01-01

Fas ligand, best known as a death-inducer, is also a costimulatory molecule required for maximal proliferation of mature antigen-specific CD4+ and CD8+ T cells. We now extend the role of Fas ligand by showing that it can also influence thymocyte development. T cell maturation in some, but not all, strains of TCR transgenic mice is severely impaired in thymocytes expressing mutant Fas ligand incapable of interacting with Fas. Mutant Fas ligand inhibits neither negative selection nor death by neglect. Instead, it appears to modulate positive selection of thymocytes expressing both class I– and class II–restricted T cell receptors of moderate affinity for their positively selecting ligands. Fas ligand is therefore an inducer of death, a costimulator of peripheral T cell activation, and an accessory molecule in positive selection. PMID:12860933

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walia, Rupali; Dardari, Rkia, E-mail: rdardari@ucalgary.ca; Chaiyakul, Mark

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 pathwaysmore » 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.« less

Peroxisome proliferator-activated receptors γ/mitochondrial uncoupling protein 2 signaling protects against seizure-induced neuronal cell death in the hippocampus following experimental status epilepticus

PubMed Central

2012-01-01

Background Status epilepticus induces subcellular changes that may lead to neuronal cell death in the hippocampus. However, the mechanism of seizure-induced neuronal cell death remains unclear. The mitochondrial uncoupling protein 2 (UCP2) is expressed in selected regions of the brain and is emerged as an endogenous neuroprotective molecule in many neurological disorders. We evaluated the neuroprotective role of UCP2 against seizure-induced hippocampal neuronal cell death under experimental status epilepticus. Methods In Sprague–Dawley rats, kainic acid (KA) was microinjected unilaterally into the hippocampal CA3 subfield to induce prolonged bilateral seizure activity. Oxidized protein level, translocation of Bcl-2, Bax and cytochrome c between cytosol and mitochondria, and expression of peroxisome proliferator-activated receptors γ (PPARγ) and UCP2 were examined in the hippocampal CA3 subfield following KA-induced status epilepticus. The effects of microinjection bilaterally into CA3 area of a PPARγ agonist, rosiglitazone or a PPARγ antagonist, GW9662 on UCP2 expression, induced superoxide anion (O2· -) production, oxidized protein level, mitochondrial respiratory chain enzyme activities, translocation of Bcl-2, Bax and cytochrome c, and DNA fragmentation in bilateral CA3 subfields were examined. Results Increased oxidized proteins and mitochondrial or cytosol translocation of Bax or cytochrome c in the hippocampal CA3 subfield was observed 3–48 h after experimental status epilepticus. Expression of PPARγ and UCP2 increased 12–48 h after KA-induced status epilepticus. Pretreatment with rosiglitazone increased UCP2 expression, reduced protein oxidation, O2· - overproduction and dysfunction of mitochondrial Complex I, hindered the translocation of Bax and cytochrome c, and reduced DNA fragmentation in the CA3 subfield. Pretreatment with GW9662 produced opposite effects. Conclusions Activation of PPARγ upregulated mitochondrial UCP2 expression

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

Hepatitis B virus-triggered autophagy targets TNFRSF10B/death receptor 5 for degradation to limit TNFSF10/TRAIL response.

PubMed

Shin, Gu-Choul; Kang, Hong Seok; Lee, Ah Ram; Kim, Kyun-Hwan

2016-12-01

Death receptors of TNFSF10/TRAIL (tumor necrosis factor superfamily member 10) contribute to immune surveillance against virus-infected or transformed cells by promoting apoptosis. Many viruses evade antiviral immunity by modulating TNFSF10 receptor signaling, leading to persistent infection. Here, we report that hepatitis B virus (HBV) X protein (HBx) restricts TNFSF10 receptor signaling via macroautophagy/autophagy-mediated degradation of TNFRSF10B/DR5, a TNFSF10 death receptor, and thus permits survival of virus-infected cells. We demonstrate that the expression of the TNFRSF10B protein is dramatically reduced both in liver tissues of chronic hepatitis B patients and in cell lines transfected with HBV or HBx. HBx-mediated downregulation of TNFRSF10B is caused by the lysosomal, but not proteasomal, degradation pathway. Immunoblotting analysis of LC3B and SQSTM1, and microscopy analysis of tandem-fluorescence-tagged LC3B revealed that HBx promotes complete autophagy. Inhibition of autophagy with a pharmacological inhibitor and LC3B knockdown revealed that HBx-induced autophagy is crucial for TNFRSF10B degradation. Immunoprecipitation and GST affinity isolation assays showed that HBx directly interacts with TNFRSF10B and recruits it to phagophores, the precursors to autophagosomes. We confirmed that autophagy activation is related to the downregulation of the TNFRSF10B protein in liver tissues of chronic hepatitis B patients. Inhibition of autophagy enhanced the susceptibility of HBx-infected hepatocytes to TNFSF10. These results identify the dual function of HBx in TNFRSF10B degradation: HBx plays a role as an autophagy receptor-like molecule, which promotes the association of TNFRSF10B with LC3B; HBx is also an autophagy inducer. Our data suggest a molecular mechanism for HBV evasion from TNFSF10-mediated antiviral immunity, which may contribute to chronic HBV infection.

Guanosine-5'-monophosphate induces cell death in rat hippocampal slices via ionotropic glutamate receptors activation and glutamate uptake inhibition.

PubMed

Molz, Simone; Dal-Cim, Tharine; Tasca, Carla I

2009-12-01

Guanine derivatives modulate the glutamatergic system through displacement of binding of glutamate to its receptors acting as antagonist of glutamate receptors in moderate to high micromolar concentrations. Guanosine-5'-monophosphate (GMP) is shown to be neuroprotective against glutamate- or oxygen/glucose deprivation-induced neurotoxicity and also against NMDA-induced apoptosis in hippocampal slices. However, in this study we are showing that high extracellular GMP concentrations (5mM) reduced cell viability in hippocampal brain slices. The toxic effect of GMP was not blocked by dipyridamole, a nucleoside transport inhibitor, nor mimicked by guanosine, suggesting an extracellular mode of action to GMP which does not involve its hydrolysis to guanosine. GMP-dependent cell damage was not blocked by P1 purinergic receptor antagonists, neither altered by adenosine A(1) or A(2A) receptor agonists. The blockage of the ionotropic glutamate receptors AMPA or NMDA, but not KA or metabotropic glutamate receptors, reversed the toxicity induced by GMP. GMP (5mM) induced a decrease in glutamate uptake into hippocampal slices, which was reversed by dl-TBOA. Therefore, GMP-induced hippocampal cell damage involves activation of ionotropic glutamate receptors and inhibition of glutamate transporters activity.

Mitochondrial fission proteins regulate programmed cell death in yeast.

PubMed

Fannjiang, Yihru; Cheng, Wen-Chih; Lee, Sarah J; Qi, Bing; Pevsner, Jonathan; McCaffery, J Michael; Hill, R Blake; Basañez, Gorka; Hardwick, J Marie

2004-11-15

The possibility that single-cell organisms undergo programmed cell death has been questioned in part because they lack several key components of the mammalian cell death machinery. However, yeast encode a homolog of human Drp1, a mitochondrial fission protein that was shown previously to promote mammalian cell death and the excessive mitochondrial fragmentation characteristic of apoptotic mammalian cells. In support of a primordial origin of programmed cell death involving mitochondria, we found that the Saccharomyces cerevisiae homolog of human Drp1, Dnm1, promotes mitochondrial fragmentation/degradation and cell death following treatment with several death stimuli. Two Dnm1-interacting factors also regulate yeast cell death. The WD40 repeat protein Mdv1/Net2 promotes cell death, consistent with its role in mitochondrial fission. In contrast to its fission function in healthy cells, Fis1 unexpectedly inhibits Dnm1-mediated mitochondrial fission and cysteine protease-dependent cell death in yeast. Furthermore, the ability of yeast Fis1 to inhibit mitochondrial fission and cell death can be functionally replaced by human Bcl-2 and Bcl-xL. Together, these findings indicate that yeast and mammalian cells have a conserved programmed death pathway regulated by a common molecular component, Drp1/Dnm1, that is inhibited by a Bcl-2-like function.