Activation of caspase-3 during Chlamydia trachomatis-induced apoptosis at a late stage

The obligate intracellular bacterium Chlamydia trachomatis activates the host cell apoptosis pathway at a late stage of its developmental cycle. However, whether caspase-3, which is a key enzyme of apoptosis, is activated in Chlamydia-infected cells remains unknown. Here, we established HEp-2 cells stably expressing cFluc-DEVD, which is a caspase-3 substrate sequence inserted into cyclic firefly luciferase, and then monitored the dynamics of caspase-3 activity in cells infected with Chlamydia. Transfected cells without infection showed a significant increase in luciferase activity due to stimulation with staurosporine, an inducer of apoptosis. Activation was significantly blocked by addition of caspase inhibitor z-VAD-fmk. Furthermore, as expected, Chlamydia infection caused a significant increase in luciferase activation at 36–48 h postinfection with a contrastive decrease at 24 h postinfection, which is already well known. Such activation caused by the infection was much stronger when the amount of bacteria was increased. Thus, caspase-3 activation was accurately monitored by the luciferase activity in HEp-2 cells constitutively expressing the cFluc-DEVD probe. Furthermore, our data showed that C. trachomatis activates caspase-3 in host cells at a late stage of infection.

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Role of Bcl-2 Family Members in Caspase-Independent Apoptosis during Chlamydia Infection

Infection and Immunity ◽

10.1128/iai.70.1.55-61.2002 ◽

2002 ◽

Vol 70 (1) ◽

pp. 55-61 ◽

Cited By ~ 65

Author(s):

Jean-Luc Perfettini ◽

John C. Reed ◽

Nicole Israël ◽

Jean-Claude Martinou ◽

Alice Dautry-Varsat ◽

...

Keyword(s):

Caspase 3 ◽

Chlamydia Psittaci ◽

Host Cells ◽

Chlamydia Infection ◽

Caspase Inhibitor ◽

Obligate Intracellular Bacterium ◽

Obligate Intracellular ◽

Infected Cells ◽

Induced Apoptosis

ABSTRACT Infection with an obligate intracellular bacterium, the Chlamydia trachomatis lymphogranuloma venereum (LGV/L2) strain or the guinea pig inclusion conjunctivitis serovar of Chlamydia psittaci, leads to apoptosis of host cells. The apoptosis is not affected by a broad-spectrum caspase inhibitor, and caspase-3 is not activated in infected cells, suggesting that apoptosis mediated by these two strains of Chlamydia is independent of known caspases. Overexpression of the proapoptotic Bcl-2 family member, Bax, was previously shown to induce caspase-independent apoptosis, and we find that Bax is activated and translocates from the cytosol to the mitochondria in C. psittaci-infected cells. C. psittaci-induced apoptosis is inhibited in host cells overexpressing Bax inhibitor-1 and is inhibited through overexpression of Bcl-2, which blocks both caspase-dependent and -independent apoptosis. As Bax and mitochondria are ideally located to sense stress-related metabolic changes emanating from the interior of an infected cell, it is likely that Bax-dependent apoptosis may also be observed in cells infected with other intracellular pathogens.

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Faculty Opinions recommendation of Chlamydia trachomatis-infected host cells resist dsRNA-induced apoptosis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.5397956.5431066 ◽

2010 ◽

Author(s):

John Brumell ◽

Danielle Brabant

Keyword(s):

Chlamydia Trachomatis ◽

Host Cells ◽

Infected Host ◽

Induced Apoptosis

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Identification of differentially expressed circular RNAs in HeLa cells infected with Chlamydia trachomatis

Pathogens and Disease ◽

10.1093/femspd/ftz062 ◽

2019 ◽

Vol 77 (7) ◽

Author(s):

Yuanjun Liu ◽

Chunmin Hu ◽

Yina Sun ◽

Haoqing Wu ◽

Xiaojun Chen ◽

...

Keyword(s):

Chlamydia Trachomatis ◽

Signaling Pathways ◽

Hela Cells ◽

Expression Profiles ◽

Quantitative Polymerase Chain Reaction ◽

Host Cells ◽

Differentially Expressed ◽

Chlamydia Infection ◽

Circular Rnas ◽

Mrna Microarray

ABSTRACT Non-coding circular RNAs (circRNAs) have been shown to have important roles in many diseases; however, no study has indicated circRNAs are involved in Chlamydia trachomatis infection. In this study, we used circRNA microarray to measure the global circRNA expression profiles in HeLa cells with or without C. trachomatis serovar E (Ct.E) infection. CircRNA/miRNA/mRNA interactions were predicted and bioinformatics analyses were performed. The differentially expressed circRNAs were selected according to our criterion for validation by reverse-transcription and quantitative polymerase chain reaction (RT-qPCR). The mRNA microarray was used to detect the mRNA expression profiles after Ct.E infection. Among 853 differentially expressed circRNAs, 453 were upregulated and 400 were downregulated after Ct.E infection. Target miRNAs and miRNA-targeted mRNAs of these circRNAs were predicted. RT-qPCR analysis indicated hsa_circRNA_001226, hsa_circRNA_007046 and hsa_circRNA_400027 were elevated similar to those determined in the circRNA microarray analysis. The mRNA microarray results showed 915 genes were upregulated and 619 genes were downregulated after Ct.E infection. Thirty-four differentially expressed genes overlapped in the bioinformatics and mRNA microarray results. KEGG pathway analysis revealed several signaling pathways, including endocytosis, MAPK and PI3P-Akt signaling pathways, that were targeted by circRNAs may play important roles in Chlamydia infection. This study provides evidence that circRNAs in host cells are involved in the process of Chlamydia infection.

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Multiple Signal Pathways Involved in Crocetin-Induced Apoptosis in KYSE-150 Cells

Pharmacology ◽

10.1159/000487956 ◽

2019 ◽

Vol 103 (5-6) ◽

pp. 263-272 ◽

Cited By ~ 6

Author(s):

Sheng Li ◽

Yuhua Qu ◽

Xiu-Yin Shen ◽

Ting Ouyang ◽

Wen-Bin Fu ◽

...

Keyword(s):

Caspase 3 ◽

Squamous Carcinoma ◽

Annexin V ◽

Signal Pathways ◽

Dependent Manner ◽

Apoptosis Pathway ◽

Anticancer Properties ◽

Multiple Signal ◽

Underlying Mechanisms ◽

Induced Apoptosis

Background: Crocetin is a carotenoid extracted from the traditional Chinese medical herb saffron. Previous studies have demonstrated that crocetin possesses anticancer properties that are effective against various cancers. As an extension of our earlier study, the present study explored the underlying mechanisms in crocetin’s anticancer effect on KYSE-150 cells. The phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT), Mitogen-activated protein kinases (MAPK), and p53/p21 signal pathways play an important role in carcinogenesis, progression, and metastasis of carcinoma cells. Thus, we investigated crocetin’s effects on the PI3K/AKT, MAPK, and p53/p21 pathways in esophageal squamous carcinoma cell line KYSE-150 cells. Methods: KYSE-150 cells were treated with various concentrations of crocetin. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltertrazolium bromide assay, Annexin V/PI stain as well as Rh123 stain were used to evaluate the cell viability, apoptosis, and MMP. Western blot was used to detect the expression of PI3K, AKT, ERK1/2, p38, c-Jun NH-terminal kinase (JNK), P53, P21, Bcl-2, Bax, and cleaved caspase-3, which were associated with cell proliferation and apoptosis. Results: Our results showed that crocetin significantly inhibited the proliferation of KYSE-150 cells in a dose- and time-dependent manner. Crocetin also markedly induced cell apoptosis. Furthermore, we have found that crocetin not only inhibited the activation of PI3K/AKT, extracellular signal–regulated kinase-1/2 (ERK1/2), and p38 but also upregulated the p53/p21 level. These regulations ultimately triggered the mitochondrial-mediated apoptosis pathway with an eventual disruption of MMP, increased levels of Bax and cleaved caspase-3, and decreased levels of Bcl-2. Conclusions: These findings suggested that crocetin interfered with multiple signal pathways in KYSE-150 cells. Therefore, this study suggested that crocetin could potentially be used as a therapeutic candidate for the treatment of esophageal cancer.

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Encephalitozoon cuniculi and Vittaforma corneae (Phylum Microsporidia) inhibit staurosporine-induced apoptosis in human THP-1 macrophages in vitro

Parasitology ◽

10.1017/s0031182018001968 ◽

2018 ◽

Vol 146 (5) ◽

pp. 569-579 ◽

Cited By ~ 1

Author(s):

Yuliya Y. Sokolova ◽

Lisa C. Bowers ◽

Xavier Alvarez ◽

Elizabeth S. Didier

Keyword(s):

Expression Profiles ◽

Life Cycles ◽

Host Cells ◽

Human Macrophage ◽

Inflammasome Activation ◽

Encephalitozoon Cuniculi ◽

Apoptosis Pathway ◽

Intrinsic Apoptosis Pathway ◽

Induced Apoptosis

AbstractObligately intracellular microsporidia regulate their host cell life cycles, including apoptosis, but this has not been evaluated in phagocytic host cells such as macrophages that can facilitate infection but also can be activated to kill microsporidia. We examined two biologically dissimilar human-infecting microsporidia species, Encephalitozoon cuniculi and Vittaforma corneae, for their effects on staurosporine-induced apoptosis in the human macrophage-differentiated cell line, THP1. Apoptosis was measured after exposure of THP-1 cells to live and dead mature organisms via direct fluorometric measurement of Caspase 3, colorimetric and fluorometric TUNEL assays, and mRNA gene expression profiles using Apoptosis RT2 Profiler PCR Array. Both species of microsporidia modulated the intrinsic apoptosis pathway. In particular, live E. cuniculi spores inhibited staurosporine-induced apoptosis as well as suppressed pro-apoptosis genes and upregulated anti-apoptosis genes more broadly than V. corneae. Exposure to dead spores induced an opposite effect. Vittaforma corneae, however, also induced inflammasome activation via Caspases 1 and 4. Of the 84 apoptosis-related genes assayed, 42 (i.e. 23 pro-apoptosis, nine anti-apoptosis, and 10 regulatory) genes were more affected including those encoding members of the Bcl2 family, caspases and their regulators, and members of the tumour necrosis factor (TNF)/TNF receptor R superfamily.

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Xylopine Induces Oxidative Stress and Causes G2/M Phase Arrest, Triggering Caspase-Mediated Apoptosis by p53-Independent Pathway in HCT116 Cells

Oxidative Medicine and Cellular Longevity ◽

10.1155/2017/7126872 ◽

2017 ◽

Vol 2017 ◽

pp. 1-13 ◽

Cited By ~ 12

Author(s):

Luciano de Souza Santos ◽

Valdenizia Rodrigues Silva ◽

Leociley Rocha Alencar Menezes ◽

Milena Botelho Pereira Soares ◽

Emmanoel Vilaça Costa ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Lines ◽

Cancer Cell ◽

Caspase 3 ◽

Cancer Cell Lines ◽

Apoptosis Pathway ◽

Phase Arrest ◽

M Phase ◽

Induced Apoptosis ◽

Hct116 Cells

Xylopine is an aporphine alkaloid that has cytotoxic activity to cancer cells. In this study, the underlying mechanism of xylopine cytotoxicity was assessed in human colon carcinoma HCT116 cells. Xylopine displayed potent cytotoxicity in different cancer cell lines in monolayer cultures and in a 3D model of cancer multicellular spheroids formed from HCT116 cells. Typical morphology of apoptosis, cell cycle arrest in the G2/M phase, increased internucleosomal DNA fragmentation, loss of the mitochondrial transmembrane potential, and increased phosphatidylserine externalization and caspase-3 activation were observed in xylopine-treated HCT116 cells. Moreover, pretreatment with a caspase-3 inhibitor (Z-DEVD-FMK), but not with a p53 inhibitor (cyclic pifithrin-α), reduced xylopine-induced apoptosis, indicating induction of caspase-mediated apoptosis by the p53-independent pathway. Treatment with xylopine also caused an increase in the production of reactive oxygen/nitrogen species (ROS/RNS), including hydrogen peroxide and nitric oxide, but not superoxide anion, and reduced glutathione levels were decreased in xylopine-treated HCT116 cells. Application of the antioxidant N-acetylcysteine reduced the ROS levels and xylopine-induced apoptosis, indicating activation of ROS-mediated apoptosis pathway. In conclusion, xylopine has potent cytotoxicity to different cancer cell lines and is able to induce oxidative stress and G2/M phase arrest, triggering caspase-mediated apoptosis by the p53-independent pathway in HCT116 cells.

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Protective Effect of Edaravone against Carbon Monoxide Induced Apoptosis in Rat Primary Cultured Astrocytes

Biochemistry Research International ◽

10.1155/2017/5839762 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 4

Author(s):

Xiaodan Xu ◽

Hong Zhang ◽

Ke Wang ◽

Tao Tu ◽

Yuan Jiang

Keyword(s):

Carbon Monoxide ◽

Membrane Potential ◽

Protective Effect ◽

Caspase 3 ◽

Prolonged Exposure ◽

Apoptosis Pathway ◽

Apoptosis Rate ◽

Cultured Astrocytes ◽

Induced Apoptosis ◽

Primary Cultured Astrocytes

Objective. To observe the protective effect of edaravone (Eda) on astrocytes after prolonged exposure to carbon monoxide (CO) and further to investigate the potential mechanisms of Eda against CO-induced apoptosis. Methods. The rat primary cultured astrocytes were cultured in vitro and exposed to 1% CO for 24 h after being cultured with different concentrations of Eda. MTT assay was used to detect the cytotoxicity of CO. Flow cytometry was used to detect the apoptosis rate, membrane potential of mitochondria, and ROS level. The mRNA and protein expressions of Bcl-2, Bax, and caspase-3 were assessed by real-time PCR and Western blotting analysis, respectively. Results. Eda can significantly suppress cytotoxicity of CO, and it can significantly increase membrane potential of mitochondria and Bcl-2 expressions and significantly suppress the apoptosis rate, ROS level, Bax, and caspase-3 expressions. Conclusion. Eda protects against CO-induced apoptosis in rat primary cultured astrocytes through decreasing ROS production and subsequently inhibiting mitochondrial apoptosis pathway.

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Lycium barbarumPolysaccharides Protect Rat Corneal Epithelial Cells against Ultraviolet B-Induced Apoptosis by Attenuating the Mitochondrial Pathway and Inhibiting JNK Phosphorylation

BioMed Research International ◽

10.1155/2017/5806832 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 5

Author(s):

Shaobo Du ◽

Biao Han ◽

Kang Li ◽

Xuan Zhang ◽

Xueli Sha ◽

...

Keyword(s):

Caspase 3 ◽

Underlying Mechanism ◽

Mitochondrial Pathway ◽

Ultraviolet B ◽

Lycium Barbarum ◽

Apoptosis Pathway ◽

Corneal Epithelial ◽

Mitochondrial Apoptosis Pathway ◽

Induced Apoptosis

Lycium barbarumpolysaccharides (LBPs) have been shown to play a key role in protecting the eyes by reducing the apoptosis induced by certain types of damage. However, it is not known whether LBPs can protect damaged corneal cells from apoptosis. Moreover, no reports have focused on the role of LBPs in guarding against ultraviolet B- (UVB-) induced apoptosis. The present study aimed to investigate the protective effect and underlying mechanism of LBPs against UVB-induced apoptosis in rat corneal epithelial (RCE) cells. The results showed that LBPs significantly prevented the loss of cell viability and inhibited cell apoptosis induced by UVB in RCE cells. LBPs also inhibited UVB-induced loss of mitochondrial membrane potential, downregulation ofBcl-2, and upregulation ofBaxand caspase-3. Finally, LBPs attenuated the phosphorylation of c-Jun NH2-terminal kinase (JNK) triggered by UVB. In summary, LBPs protect RCE cells against UVB-induced damage and apoptosis, and the underlying mechanism involves the attenuation of the mitochondrial apoptosis pathway and the inhibition of JNK phosphorylation.

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