scholarly journals The Major Apoptotic Pathway Activated and Suppressed by Poliovirus

2003 ◽  
Vol 77 (1) ◽  
pp. 45-56 ◽  
Author(s):  
George A. Belov ◽  
Lyudmila I. Romanova ◽  
Elena A. Tolskaya ◽  
Marina S. Kolesnikova ◽  
Yuri A. Lazebnik ◽  
...  
Keyword(s):  
Program Implementation ◽  
Caspase 3 ◽  
Chromatin Condensation ◽  
Productive Infection ◽  
Caspase 9 ◽  
Apoptotic Pathway ◽  
Poliovirus Infection ◽  
Proapoptotic Protein ◽  
Infected Cells ◽  
Induced Apoptosis

ABSTRACT Cells respond to poliovirus infection by switching on the apoptotic program, implementation of which is usually suppressed by viral antiapoptotic functions. We show here that poliovirus infection of HeLa cells or derivatives of MCF-7 cells was accompanied by the efflux of cytochrome c from mitochondria. This efflux occurred during both abortive infection (e.g., interrupted by guanidine-HCl and ending with apoptosis) and productive infection (leading to cytopathic effect). The former type of infection, but not the latter, was accompanied by truncation of the proapoptotic protein Bid. The virus-triggered cytochrome c efflux was suppressed by overexpression of Bcl-2. Both abortive and productive infections also resulted in a decreased level of procaspase-9, as revealed by Western blotting. In the former case, this decrease was accompanied by the accumulation of a protein with the electrophoretic mobility of active caspase-9. In contrast, in the productively infected cells, the latter protein was absent but caspase-9-related polypeptides with altered mobility could be detected. Both caspase-9 and caspase-3 were shown to be essential for the development of such hallmarks of virus-induced apoptosis as chromatin condensation, DNA degradation, and nuclear fragmentation. These and some other results suggest the following scenario. Poliovirus infection activates the apoptotic pathway, involving mitochondrial damage, cytochrome c efflux, and consecutive activation of caspase-9 and caspase-3. The apoptotic signal appears to be amplified by a loop which includes secondary processing of Bid. The implementation of the apoptotic program in productively infected cells may be suppressed, however, by the viral antiapoptotic functions, which act at a step(s) downstream of the cytochrome c efflux. The suppression appears to be caused, at least in part, by aberrant processing and degradation of procaspase-9.

scholarly journals The mitochondrial pathway of apoptosis is triggered during feline calicivirus infection

2006 ◽  
Vol 87 (2) ◽  
pp. 357-361 ◽  
Author(s):  
Alessandro Natoni ◽  
George E. N. Kass ◽  
Michael J. Carter ◽  
Lisa O. Roberts
Keyword(s):  
Caspase 3 ◽  
Chromatin Condensation ◽  
Mitochondrial Pathway ◽  
Feline Calicivirus ◽  
Upper Respiratory Tract ◽  
Caspase 9 ◽  
The Family ◽  
Infected Cells ◽  
Upper Respiratory ◽  
Subsequent Activation

Feline calicivirus (FCV) belongs to the family Caliciviridae and is an important pathogen of the upper respiratory tract of cats. Recent studies have shown that cells infected with FCV undergo apoptosis, as evidenced by caspase activation, chromatin condensation and cleavage of poly(ADP-ribose) polymerase. Here, the upstream events were investigated in order to define the molecular mechanism of apoptosis in FCV-infected cells. It was shown that FCV induced translocation of phosphatidylserine to the cell outer membrane and release of cytochrome c from mitochondria at about 6–8 h post-infection. These events were preceded by the loss of mitochondrial membrane potential and Bax translocation from the cytosol to mitochondria between 4 and 6 h after infection. Release of cytochrome c from mitochondria triggered the activation of caspase-9 and the subsequent activation of the executioner caspase, caspase-3. These results suggest that the mitochondrial pathway of apoptosis is triggered during FCV infection.

scholarly journals Mitigation of H2O2-Induced Mitochondrial-Mediated Apoptosis in NG108-15 Cells by Novel Mesuagenin C fromMesua kunstleri(King) Kosterm

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Gomathi Chan ◽  
Muhamad Noor Alfarizal Kamarudin ◽  
Daniel Zin Hua Wong ◽  
Nor Hadiani Ismail ◽  
Faizuri Abdul Latif ◽  
...  
Keyword(s):  
Cell Viability ◽  
Caspase 3 ◽  
Chromatin Condensation ◽  
Annexin V ◽  
Data Interpretation ◽  
Hexane Extract ◽  
Neuroprotective Activity ◽  
Apoptotic Pathway ◽  
Chemical Structures ◽  
Induced Apoptosis

This study was aimed to isolate and evaluate neuroprotective compounds from the hexane extract of the bark ofMesua kunstleri(Clusiaceae) on H2O2-induced apoptosis in NG108-15 cells. Five 4-phenylcoumarins were isolated by using various chromatographic techniques via neuroprotective activity-guided fractionation and isolation from the active hexane extract. The chemical structures of the isolated compounds were confirmed by NMR spectroscopic data interpretation and comparison with literature values. Cell viability data demonstrated that mesuagenin C3significantly increased cell viability. Hoechst 33342/PI staining illustrated mesuagenin C3was able to abate the nuclear shrinkage, chromatin condensation and formation of apoptotic bodies. Pretreatment with mesuagenin C3reduced total annexin V positive cells and increased the level of intracellular glutathione (GSH). Mesuagenin C3attenuated membrane potential (Δψm), reduced Bax/Bcl-2 ratio and inactivated of caspase-3/7 and -9. These results indicated that mesuagenin C3could protect NG108-15 cells against H2O2-induced apoptosis by increasing intracellular GSH level, aggrandizingΔψm, and modulating apoptotic signalling pathway through Bcl-2 family and caspase-3/7 and -9. These findings confirmed the involvement of intrinsic apoptotic pathway in H2O2-induced apoptosis and suggested that mesuagenin C3may have potential therapeutic properties for neurodegenerative diseases.

scholarly journals Delineation of the Molecular Mechanisms of Francisella tularensis-Induced Apoptosis in Murine Macrophages

2003 ◽  
Vol 71 (8) ◽  
pp. 4642-4646 ◽  
Author(s):  
Xin-He Lai ◽  
Anders Sjöstedt
Keyword(s):  
Francisella Tularensis ◽  
Mitochondrial Membrane ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Live Vaccine Strain ◽  
Intrinsic Apoptotic Pathway ◽  
Caspase 9 ◽  
Apoptotic Pathway ◽  
Murine Macrophages ◽  
Induced Apoptosis

ABSTRACT Francisella tularensis is a facultative intracellular bacterium capable of inducing apoptosis in murine macrophages. Here we analyzed the pathway leading to apoptosis in the murine macrophage-like cell line J774A.1 after infection with F. tularensis strain LVS (named LVS for live vaccine strain). We obtained evidence that the infection affected the mitochondria of the macrophages, since it induced release of the mitochondrial molecule cytochrome c into the cytosol and changed the potential over the mitochondrial membrane. Moreover, activation of caspase 9 and the executioner caspase 3 was also observed in the LVS-infected J774A.1 macrophages. The activated caspase 3 degraded poly(ADP-ribose) polymerase (PARP). All of these events were observed within 9 to 12 h after the initiation of infection, and maximum degradation of a synthetic caspase 3 substrate occurred at 18 h. The internucleosomal fragmentation and PARP degradation resulting from activation of this apoptotic pathway was prevented by the caspase 3 inhibitor Z-DEVD-fmk. No involvement of caspase 1, caspase 8, Bcl-2, or Bid was observed. Thus, the F. tularensis infection induces macrophage apoptosis through a pathway partly resembling the intrinsic apoptotic pathway.

scholarly journals Bak and Bax Function To Limit Adenovirus Replication through Apoptosis Induction

2002 ◽  
Vol 76 (9) ◽  
pp. 4547-4558 ◽  
Author(s):  
Andrea Cuconati ◽  
Kurt Degenhardt ◽  
Ramya Sundararajan ◽  
Alan Anschel ◽  
Eileen White
Keyword(s):  
Cellular Level ◽  
Productive Infection ◽  
Apoptosis Induction ◽  
Wild Type ◽  
Caspase 9 ◽  
Proliferation And Apoptosis ◽  
Infected Cells ◽  
Induced Apoptosis ◽  
Induced Changes ◽  
Adenovirus Replication

ABSTRACT Adenovirus infection and expression of E1A induces both proliferation and apoptosis, the latter of which is blocked by the adenovirus Bcl-2 homologue E1B 19K. The mechanism of apoptosis induction and the role that it plays in productive infection are not known. Unlike apoptosis mediated by death receptors, infection with proapoptotic E1B 19K mutant viruses did not induce cleavage of Bid but nonetheless induced changes in Bak and Bax conformation, Bak-Bax interaction, caspase 9 and 3 activation, and apoptosis. In wild-type-adenovirus-infected cells, in which E1B 19K inhibits apoptosis, E1B 19K was bound to Bak, precluding Bak-Bax interaction and changes in Bax conformation. Infection with E1B 19K mutant viruses induced apoptosis in wild-type and Bax- or Bak-deficient baby mouse kidney cells but not in those deficient for both Bax and Bak. Furthermore, Bax and Bak deficiency dramatically increased E1A expression and virus replication. Thus, Bax- and Bak-mediated apoptosis severely limits adenoviral replication, demonstrating that Bax and Bak function as an antiviral response at the cellular level.

scholarly journals Shigella flexneri Inhibits Staurosporine-Induced Apoptosis in Epithelial Cells

2007 ◽  
Vol 75 (5) ◽  
pp. 2531-2539 ◽  
Author(s):  
Christina S. Clark ◽  
Anthony T. Maurelli
Keyword(s):  
Epithelial Cells ◽  
Type Iii Secretion ◽  
Caspase 3 ◽  
Shigella Flexneri ◽  
Nuclear Staining ◽  
Caspase 9 ◽  
Gentamicin Protection Assay ◽  
Infected Cells ◽  
Induced Apoptosis ◽  
Bacterial Genes

ABSTRACT Shigella flexneri is a facultative intracellular organism that causes bacillary dysentery. The Shigella IpaB protein activates caspase 1 in macrophages, which eventually leads to apoptosis. In contrast, epithelial cells infected with Shigella undergo a stress response but do not die. Therefore, the objective of this study was to determine if Shigella has the ability to inhibit apoptosis in epithelial cells. A modified gentamicin protection assay was used to investigate if HeLa cells infected with S. flexneri are able to resist the induction of apoptosis following treatment with 4 μM of staurosporine. Nuclear staining and immunofluorescence revealed that infected cells remained healthy while uninfected cells appeared apoptotic. Only uninfected cells had detectable levels of activated caspase 3 upon immunofluorescence, and this was verified by Western blot analysis. Despite interfering with caspase 3 activation, Shigella-infected cells treated with staurosporine did have cytochrome c release and caspase 9 activation, indicating that Shigella protects epithelial cells from apoptosis by inhibiting caspase 3 activation. Analysis of S. flexneri mutants showed that invasion and a functional type III secretion system were required to block apoptosis. In addition, a mutant with a deletion in mxiE, which encodes a transcriptional activator for genes induced intracellularly, failed to inhibit apoptosis. Therefore, protection of epithelial cells from apoptosis by S. flexneri is regulated by one or more of the bacterial genes under the control of mxiE. We believe that S. flexneri, like other pathogens, inhibits apoptosis in epithelial cells but causes apoptosis in macrophages to ensure survival inside the host.

scholarly journals Role of the Mitochondrial Signaling Pathway in Murine Coronavirus-Induced Oligodendrocyte Apoptosis

2006 ◽  
Vol 80 (1) ◽  
pp. 395-403 ◽  
Author(s):  
Yin Liu ◽  
Yinghui Pu ◽  
Xuming Zhang
Keyword(s):  
Hepatitis Virus ◽  
Mitochondrial Pathway ◽  
Caspase 8 ◽  
Caspase 9 ◽  
Apoptotic Pathway ◽  
Antiapoptotic Proteins ◽  
Mitochondrial Signaling ◽  
Drastic Increase ◽  
Infected Cells

ABSTRACT A previous study demonstrated that infection of rat oligodendrocytes by mouse hepatitis virus (MHV) resulted in apoptosis, which is caspase dependent (Y. Liu, Y. Cai, and X. Zhang, J. Virol. 77:11952-11963, 2003). Here we determined the involvement of the mitochondrial pathway in MHV-induced oligodendrocyte apoptosis. We found that caspase-9 activity was 12-fold higher in virus-infected cells than in mock-infected cells at 24 h postinfection (p.i.). Pretreatment of cells with a caspase-9 inhibitor completely blocked caspase-9 activation and partially inhibited the apoptosis mediated by MHV infection. Analyses of cytochrome c release further revealed an activation of the mitochondrial apoptotic pathway. Stable overexpression of the two antiapoptotic proteins Bcl-2 and Bcl-xL significantly, though only partially, blocked apoptosis, suggesting that activation of the mitochondrial pathway is partially responsible for the apoptosis. To identify upstream signals, we determined caspase-8 activity, cleavage of Bid, and expression of Bax and Bad by Western blotting. We found a drastic increase in caspase-8 activity and cleavage of Bid at 24 h p.i. in virus-infected cells, suggesting that Bid may serve as a messenger to relay the signals from caspase-8 to mitochondria. However, treatment with a caspase-8 inhibitor only slightly blocked cytochrome c release from the mitochondria. Furthermore, we found that Bax but not Bad was significantly increased at 12 h p.i. in cells infected with both live and UV-inactivated viruses and that Bax activation was partially blocked by treatment with the caspase-8 inhibitor. These results thus establish the involvement of the mitochondrial pathway in MHV-induced oligodendrocyte apoptosis.

Role of protein kinase C-η in cigarette smoke extract-induced apoptosis in MRC-5-cells

2014 ◽  
Vol 34 (9) ◽  
pp. 869-877 ◽  
Author(s):  
ES Son ◽  
SY Kyung ◽  
SP Lee ◽  
SH Jeong ◽  
JY Shin ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cigarette Smoke ◽  
Caspase 3 ◽  
Dominant Negative ◽  
Lung Fibroblasts ◽  
Apoptotic Pathway ◽  
Kinase C ◽  
Extrinsic Apoptotic Pathway ◽  
Infected Cells

Cigarette smoke (CS) is a major risk factor for emphysema, which causes cell death in structural cells of the lung by mechanisms that are still not completely understood. We demonstrated previously that CS extract (CSE) induces caspase activation in MRC-5 human lung fibroblasts, activated protein kinase C-η (PKC-η), and translocated PKC-η from the cytosol to the membrane. The objective of this study was to investigate the involvement of PKC-η activation in a CSE-induced extrinsic apoptotic pathway. We determined that CSE increases expression of caspase 3 and 8 cleavage in MRC-5 cells and overexpression of PKC-η significantly increased expression of caspase 3 and 8 cleavage compared with control LacZ-infected cells. In contrast, dominant negative (dn) PKC-η inhibited apoptosis in MRC-5 cells exposed to CSE and decreased expression of caspase 3 and 8 compared with control cells. Exposure to 10% CSE for >8 h significantly increased lactate dehydrogenase release in PKC-η-infected cells compared with LacZ-infected cells. Additionally, PKC-η-infected cells had an increased number of Hoechst 33342 stained nuclei compared with LacZ-infected cells, while dn PKC-η-infected cells exhibited fewer morphological changes than LacZ-infected cells under phase-contrast microscopy. In conclusion, PKC-η activation plays a pro-apoptotic role in CSE-induced extrinsic apoptotic pathway in MRC-5 cells. These results suggest that modulation of PKC-η may be a useful tool for regulating the extrinsic apoptosis of MRC-5 cells by CSE and may have therapeutic potential in the treatment of CS-induced lung injury.

Reactive oxygen species and caspase activation mediate silica-induced apoptosis in alveolar macrophages

2001 ◽  
Vol 280 (1) ◽  
pp. L10-L17 ◽  
Author(s):  
Han-Ming Shen ◽  
Zhuo Zhang ◽  
Qi-Feng Zhang ◽  
Choon-Nam Ong
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Alveolar Macrophages ◽  
Caspase 3 ◽  
Reactive Oxygen ◽  
Parp Cleavage ◽  
Oxygen Species ◽  
Caspase Activation ◽  
Caspase 9 ◽  
Induced Apoptosis

Alveolar macrophages (AMs) are the principal target cells of silica and occupy a key position in the pathogenesis of silica-related diseases. Silica has been found to induce apoptosis in AMs, whereas its underlying mechanisms involving the initiation and execution of apoptosis are largely unknown. The main objective of the present study was to examine the form of cell death caused by silica and the mechanisms involved. Silica-induced apoptosis in AMs was evaluated by terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling assay and cell cycle/DNA content analysis. The elevated level of reactive oxygen species (ROS), caspase-9 and caspase-3 activation, and poly(ADP-ribose) polymerase (PARP) cleavage in silica-treated AMs were also determined. The results showed that there was a temporal pattern of apoptotic events in silica-treated AMs, starting with ROS formation and followed by caspase-9 and caspase-3 activation, PARP cleavage, and DNA fragmentation. Silica-induced apoptosis was significantly attenuated by a caspase-3 inhibitor, N-acetyl-Asp-Glu-Val-Asp aldehyde, and ebselen, a potent antioxidant. These findings suggest that apoptosis is an important form of cell death caused by silica exposure in which the elevated ROS level that results from silica exposure may act as an initiator, leading to caspase activation and PARP cleavage to execute the apoptotic process.

Identification of apoptotic genes mediating TGF-β/Smad3-induced cell death in intestinal epithelial cells using a genomic approach

2007 ◽  
Vol 292 (1) ◽  
pp. G28-G38 ◽  
Author(s):  
Yanna Cao ◽  
Lu Chen ◽  
Weili Zhang ◽  
Yan Liu ◽  
Harry T. Papaconstantinou ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Target Genes ◽  
Transforming Growth Factor ◽  
Intestinal Epithelial ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Genomic Approach ◽  
Apoptotic Genes ◽  
Induced Apoptosis

Transforming growth factor (TGF)-β-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues in vivo. Previously, we have shown that TGF-β inhibits the growth of rat intestinal epithelial (RIE)-1 cells. However, RIE-1 cells are relatively resistant to TGF-β-induced apoptosis due to a low endogenous Smad3-to-Akt ratio. Overexpression of Smad3 sensitizes RIE-1 cells (RIE-1/Smad3) to TGF-β-induced apoptosis by altering the Smad3-to-Akt ratio in favor of apoptosis. In this study, we utilized a genomic approach to identify potential downstream target genes that are regulated by TGF-β/Smad3. Total RNA samples were analyzed using Affymetrix oligonucleotide microarrays. We found that TGF-β regulated 518 probe sets corresponding to its target genes. Interestingly, among the known apoptotic genes included in the microarray analyses, only caspase-3 was induced, which was confirmed by real-time RT-PCR. Furthermore, TGF-β activated caspase-3 through protein cleavage. Upstream of caspase-3, TGF-β induced mitochondrial depolarization, cytochrome c release, and cleavage of caspase-9, which suggests that the intrinsic apoptotic pathway mediates TGF-β-induced apoptosis in RIE-1/Smad3 cells.

LPA protects intestinal epithelial cells from apoptosis by inhibiting the mitochondrial pathway

2003 ◽  
Vol 284 (5) ◽  
pp. G821-G829 ◽  
Author(s):  
Wenlin Deng ◽  
De-An Wang ◽  
Elvira Gosmanova ◽  
Leonard R. Johnson ◽  
Gabor Tigyi
Keyword(s):  
Epithelial Cells ◽  
Cytochrome C ◽  
Protein Expression ◽  
Caspase 3 ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Antiapoptotic Activity

We previously showed ( Gastroenterology 123: 206–216, 2002) that lysophosphatidic acid (LPA) protects and rescues rat intestinal epithelial cells (IEC-6) from apoptosis. Here, we provide evidence for the LPA-elicited inhibition of the mitochondrial apoptotic pathway leading to attenuation of caspase-3 activation. Pretreatment of IEC-6 cells with LPA inhibited campothecin-induced caspase-9 and caspase-3 activation and DNA fragmentation. A caspase-9 inhibitor peptide mimicked the LPA-elicited antiapoptotic activity. LPA elicited ERK1/ERK2 and PKB/Akt phosphorylation. The LPA-elicited antiapoptotic activity and inhibition of caspase-9 activity were abrogated by pertussis toxin, PD 98059, wortmannin, and LY 294002. LPA reduced cytochrome c release from mitochondria and prevented activation of caspase-9. LPA prevented translocation of Bax from cytosol to mitochondria and increased the expression of the antiapoptotic Bcl-2 mRNA and protein. LPA had no effect on Bcl-xl, Bad, and Bak mRNA or protein expression. These data indicate that LPA protects IEC-6 cells from camptothecin-induced apoptosis through Gi-coupled inhibition of caspase-3 activation mediated by the attenuation of caspase-9 activation due to diminished cytochrome c release, involving upregulation of Bcl-2 protein expression and prevention of Bax translocation.

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