scholarly journals Chinese Giant Salamander (Andrias davidianus) Iridovirus Infection Leads to Apoptotic Cell Death through Mitochondrial Damage, Caspases Activation, and Expression of Apoptotic-Related Genes

2019 ◽  
Vol 20 (24) ◽  
pp. 6149 ◽  
Author(s):  
Yiqun Li ◽  
Nan Jiang ◽  
Yuding Fan ◽  
Yong Zhou ◽  
Wenzhi Liu ◽  
...  
Keyword(s):  
Cell Death ◽  
Apoptotic Cell ◽  
Mitochondrial Damage ◽  
Apoptotic Cell Death ◽  
Economic Losses ◽  
P53 Expression ◽  
Andrias Davidianus ◽  
Chinese Giant Salamander ◽  
Infected Cells ◽  
Apoptotic Genes

Chinese giant salamander iridovirus (GSIV) is the causative pathogen of Chinese giant salamander (Andrias davidianus) iridovirosis, leading to severe infectious disease and huge economic losses. However, the infection mechanism by GSIV is far from clear. In this study, a Chinese giant salamander muscle (GSM) cell line is used to investigate the mechanism of cell death during GSIV infection. Microscopy observation and DNA ladder analysis revealed that DNA fragmentation happens during GSIV infection. Flow cytometry analysis showed that apoptotic cells in GSIV-infected cells were significantly higher than that in control cells. Caspase 8, 9, and 3 were activated in GSIV-infected cells compared with the uninfected cells. Consistently, mitochondria membrane potential (MMP) was significantly reduced, and cytochrome c was released into cytosol during GSIV infection. p53 expression increased at an early stage of GSIV infection and then slightly decreased late in infection. Furthermore, mRNA expression levels of pro-apoptotic genes participating in the extrinsic and intrinsic pathway were significantly up-regulated during GSIV infection, while those of anti-apoptotic genes were restrained in early infection and then rose in late infection. These results collectively indicate that GSIV induces GSM apoptotic cell death involving mitochondrial damage, caspases activation, p53 expression, and pro-apoptotic molecules up-regulation.

scholarly journals Activation and Antagonism of the OAS–RNase L Pathway

Proceedings ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 14
Author(s):  
Susan R. Weiss
Keyword(s):  
Cell Death ◽  
Antiviral Activity ◽  
Apoptotic Cell ◽  
Early Response ◽  
Apoptotic Cell Death ◽  
Rnase L ◽  
Oligoadenylate Synthetase ◽  
Viral Genomes ◽  
L System ◽  
Infected Cells

The oligoadenylate synthetase–ribonuclease L (OAS–RNase L) system is a potent antiviral pathway that severely limits the pathogenesis of many viruses. Upon sensing dsRNA, OASs produce 2′,5′-oligoadenylates (2-5A) that activate RNase L to cleave both host and viral single-stranded RNA, thereby limiting protein production, virus replication and spread, leading to apoptotic cell death. Endogenous host dsRNA, which accumulates in the absence of adenosine deaminase acting on RNA (ADAR)1, can also activate RNase L and lead to apoptotic cell death. RNase L activation and antiviral activity during infections with several types of viruses in human and bat cells is dependent on OAS3 but independent of virus-induced interferon (IFN) and, thus, RNase L can be activated even in the presence of IFN antagonists. Differently from other human viruses examined, Zika virus is resistant to the antiviral activity of RNase L and instead utilizes RNase L to enhance its replication factories to produce more infectious virus. Some betacoronaviruses antagonize RNase L activation by expressing 2′,5′-phosphodiesterases (PDEs) that cleave 2-5A and thereby antagonize activation of RNase L. The best characterized of these PDEs is the murine coronavirus (MHV) NS2 accessory protein. Enzymatically active NS2 is required for replication in myeloid cells and in the liver. Interestingly, while wild type mice clear MHV from the liver by 7–10 days post-infection, RNase L knockout mice fail to effectively clear MHV, probably due to diminished apoptotic death of infected cells. We suggest that RNase L antiviral activity stems from direct cleavage of viral genomes and cessation of protein synthesis as well as through promoting death of infected cells, limiting the spread of virus. Importantly, OASs are pattern recognition receptors and the OAS–RNase L pathway is a primary innate response pathway to viruses, capable of early response, coming into play before IFN is induced or when the virus shuts down IFN signaling.

scholarly journals Autophagy Promotes Porcine Parvovirus Replication and Induces Non-Apoptotic Cell Death in Porcine Placental Trophoblasts

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 15
Author(s):  
Xiujuan Zhang ◽  
Yingli Xiong ◽  
Jie Zhang ◽  
Ting Shao ◽  
Songbiao Chen ◽  
...  
Keyword(s):  
Cell Death ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Porcine Parvovirus ◽  
Caspase Inhibitor ◽  
Autophagy Flux ◽  
Autophagy Induction ◽  
Cellular Apoptosis ◽  
Infected Cells ◽  
Later Phase

Autophagy plays important roles in the infection and pathogenesis of many viruses, yet the regulatory roles of autophagy in the process of porcine parvovirus (PPV) infection remain unclear. Herein, we show that PPV infection induces autophagy in porcine placental trophoblasts (PTCs). Induction of autophagy by rapamycin (RAPA) inhibited the occurrence of apoptotic cell death, yet promoted viral replication in PPV-infected cells; inhibition of autophagy by 3-MA or ATG5 knockdown increased cellular apoptosis and reduced PPV replication. Interestingly, we found that in the presence of caspase-inhibitor zVAD-fmk, PPV induces non-apoptotic cell death that was characterized by lysosomal damage and associated with autophagy. Induction of complete autophagy flux by RAPA markedly promoted PPV replication compared with incomplete autophagy induced by RAPA plus bafilomycin (RAPA/BAF) in the early phase of PPV infection (24 h.p.i.). Meanwhile, induction of complete autophagy with RAPA increased lysosomal damage and non-apoptotic cell death in the later phase of PPV infection. Therefore, our data suggest that autophagy can enhance PPV replication and promote the occurrence of lysosomal-damage-associated non-apoptotic cell death in PPV-infected porcine placental trophoblasts.

scholarly journals Flavivirus Activates Phosphatidylinositol 3-Kinase Signaling To Block Caspase-Dependent Apoptotic Cell Death at the Early Stage of Virus Infection

2005 ◽  
Vol 79 (13) ◽  
pp. 8388-8399 ◽  
Author(s):  
Chyan-Jang Lee ◽  
Ching-Len Liao ◽  
Yi-Ling Lin
Keyword(s):  
Cell Death ◽  
Virus Infection ◽  
Apoptotic Cell ◽  
Early Stage ◽  
Akt Signaling ◽  
Apoptotic Cell Death ◽  
Phosphatidylinositol 3 Kinase ◽  
Caspase 9 ◽  
Pi3k Activation ◽  
Infected Cells

ABSTRACT Flaviviruses such as dengue virus (DEN) and Japanese encephalitis virus (JEV) are medically important in humans. The lipid kinase, phosphatidylinositol 3-kinase (PI3K) and its downstream target Akt have been implicated in the regulation of diverse cellular functions such as proliferation, and apoptosis. Since JEV and DEN appear to trigger apoptosis in cultured cells at a rather late stage of infection, we evaluated the possible roles of the PI3K/Akt signaling pathway in flavivirus-infected cells. We found that Akt phosphorylation was noticeable in the JEV- and DEN serotype 2 (DEN-2)-infected neuronal N18 cells in an early, transient, PI3K- and lipid raft-dependent manner. Blocking of PI3K activation by its specific inhibitor LY294002 or wortmannin greatly enhanced virus-induced cytopathic effects (CPEs), even at an early stage of infection, but had no effect on virus production. This severe CPE was characterized as apoptotic cell death as evidenced by TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) staining and cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP). Mechanically, the initiator and effector caspases involved are mainly caspase-9 and caspase-6, since only a pan-caspase inhibitor and the inhibitors preferentially target caspase-9 and -6, but not the ones antagonizing caspase-8, -3, or -7 alleviated the levels of PARP cleavage after virus infection and PI3K blockage. Furthermore, Bcl-2 appears to be a crucial mediator downstream of PI3K/Akt signaling, since overexpression of Bcl-2 reduced virus-induced apoptosis even when PI3K activation was repressed. Collectively, our results suggest an antiapoptotic role for the PI3K/Akt pathway triggered by JEV and DEN-2 to protect infected cells from early apoptotic cell death.

scholarly journals HMG-CoA reductase is negatively associated with PCV2 infection and PCV2-induced apoptotic cell death

2014 ◽  
Vol 95 (6) ◽  
pp. 1330-1337 ◽  
Author(s):  
Xin Yang ◽  
Hongsheng Ouyang ◽  
Fuwang Chen ◽  
Daxing Pang ◽  
Meichen Dong ◽  
...  
Keyword(s):  
Cell Death ◽  
Caspase 3 ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Pcv2 Infection ◽  
Apoptotic Response ◽  
Negatively Associated ◽  
Infected Cells ◽  
Coa Reductase ◽  
Pcv2 Replication

We examined the role of HMG-CoA reductase (HMGCR) during porcine circovirus 2 (PCV2) infection. The results demonstrated that levels of endogenous HMGCR were not significantly different in PCV2-infected cells and mock-infected cells. However, the level of phosphorylated HMGCR, an inactivated form of HMGCR, was increased in PCV2-infected cells. Furthermore, HMGCR was upregulated by overexpression, silenced by siRNA or inactivated using its dominant-negative form in PK-15 cells. The results showed that PCV2 infection was inhibited by HMGCR overexpression, whereas it was significantly increased in HMGCR-silenced cells and HMGCR inhibitor-treated cells. Moreover, there was a robust apoptotic response at 48 h post-infection (p.i.) in HMGCR-inactivated cells, and this response was significantly greater than that observed in PK-15 cells. A modest apoptotic response was also observed in HMGCR-silenced cells. Caspase-3 activity was also analysed in PCV2-infected cells at 48 h p.i. As expected, caspase-3 activity was significantly increased in HMGCR-inactivated and -silenced cells compared with PK-15 cells. PCV2 replication was dose-dependently increased in HMGCR-inactivated cells when treated with increasing amounts of caspase-3 inhibitor. Altogether, HMGCR was negatively associated with PCV2 infection and PCV2-induced apoptotic cell death. These data demonstrated that HMGCR can be used as a candidate target for PCV2 disease control and antivirus research. Furthermore, the cells generated in this study can be used to evaluate the potential effects of HMGCR on PCV2 replication.

scholarly journals l-Serine protects mouse hippocampal neuronal HT22 cells against oxidative stress-mediated mitochondrial damage and apoptotic cell death

2019 ◽  
Vol 141 ◽  
pp. 447-460 ◽  
Author(s):  
Ki Yun Kim ◽  
Su-Kyeong Hwang ◽  
Shin Young Park ◽  
Min Ju Kim ◽  
Do Youn Jun ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Apoptotic Cell ◽  
Mitochondrial Damage ◽  
Apoptotic Cell Death

Ampelopsin Induces DR5-Mediated Apoptotic Cell Death in EBV-Infected Cells through the p38 Pathway

2019 ◽  
Vol 72 (3) ◽  
pp. 489-494
Author(s):  
Sun-Mi Yun ◽  
Yeong Seok Kim ◽  
Ki Hoon Kim ◽  
Dae Young Hur
Keyword(s):  
Cell Death ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Infected Cells ◽  
P38 Pathway
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