scholarly journals Virulence of Vibrio alginolyticus Accentuates Apoptosis and Immune Rigor in the Oyster Crassostrea hongkongensis

2021 ◽  
Vol 12 ◽  
Author(s):  
Fan Mao ◽  
Kunna Liu ◽  
Nai-Kei Wong ◽  
Xiangyu Zhang ◽  
Wenjie Yi ◽  
...  
Keyword(s):  
Emerging Infectious Diseases ◽  
Vibrio Alginolyticus ◽  
Adaptive Responses ◽  
Crassostrea Hongkongensis ◽  
Functional Studies ◽  
Defensive Strategies ◽  
Pathogen Virulence ◽  
Encoding Gene ◽  
Apoptotic Pathways ◽  
Induced Apoptosis

Vibrio species are ubiquitously distributed in marine environments, with important implications for emerging infectious diseases. However, relatively little is known about defensive strategies deployed by hosts against Vibrio pathogens of distinct virulence traits. Being an ecologically relevant host, the oyster Crassostrea hongkongensis can serve as an excellent model for elucidating mechanisms underlying host-Vibrio interactions. We generated a Vibrio alginolyticus mutant strain (V. alginolyticus△vscC) with attenuated virulence by knocking out the vscC encoding gene, a core component of type III secretion system (T3SS), which led to starkly reduced apoptotic rates in hemocyte hosts compared to the V. alginolyticusWT control. In comparative proteomics, it was revealed that distinct immune responses arose upon encounter with V. alginolyticus strains of different virulence. Quite strikingly, the peroxisomal and apoptotic pathways are activated by V. alginolyticusWT infection, whereas phagocytosis and cell adhesion were enhanced in V. alginolyticus△vscC infection. Results for functional studies further show that V. alginolyticusWT strain stimulated respiratory bursts to produce excess superoxide (O2•−) and hydrogen peroxide (H2O2) in oysters, which induced apoptosis regulated by p53 target protein (p53tp). Simultaneously, a drop in sGC content balanced off cGMP accumulation in hemocytes and repressed the occurrence of apoptosis to a certain extent during V. alginolyticus△vscC infection. We have thus provided the first direct evidence for a mechanistic link between virulence of Vibrio spp. and its immunomodulation effects on apoptosis in the oyster. Collectively, we conclude that adaptive responses in host defenses are partially determined by pathogen virulence, in order to safeguard efficiency and timeliness in bacterial clearance.

Caspase-2 is activated at the CD95 death-inducing signaling complex in the course of CD95-induced apoptosis

Blood ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 559-565 ◽  
Author(s):  
Inna N. Lavrik ◽  
Alexander Golks ◽  
Simone Baumann ◽  
Peter H. Krammer
Keyword(s):  
B Cell ◽  
Molecular Mechanism ◽  
Cell Lines ◽  
Caspase 8 ◽  
Signaling Complex ◽  
Deficient Cell ◽  
Apoptotic Pathways ◽  
Caspase 2 ◽  
Induced Apoptosis

Caspase-2 was reported to be involved in a number of apoptotic pathways triggered by various stimuli. However, the molecular mechanism of procaspase-2 activation in the course of apoptosis remains poorly defined. In this report, we demonstrate that procaspase-2 is recruited to the CD95 (Fas/APO-1) death-inducing signaling complex (DISC) in human T- and B-cell lines. We show that procaspase-2 is activated at the DISC on CD95 stimulation. Despite its presence at the DISC, caspase-2 does not initiate apoptosis on CD95 stimulation in caspase-8–deficient cell lines. Taken together, our data reveal that caspase-2 is activated at the DISC but does not play an initiating role in the CD95-induced apoptosis.

scholarly journals Elevated virulence of an emerging viral genotype as a driver of honeybee loss

2016 ◽  
Vol 283 (1833) ◽  
pp. 20160811 ◽  
Author(s):  
Dino P. McMahon ◽  
Myrsini E. Natsopoulou ◽  
Vincent Doublet ◽  
Matthias Fürst ◽  
Silvio Weging ◽  
...  
Keyword(s):  
Emerging Infectious Diseases ◽  
Genetic Identity ◽  
Accurate Identification ◽  
Deformed Wing Virus ◽  
Species Decline ◽  
Biodiversity Crisis ◽  
Pathogen Virulence ◽  
Population Loss ◽  
Genome Wide

Emerging infectious diseases (EIDs) have contributed significantly to the current biodiversity crisis, leading to widespread epidemics and population loss. Owing to genetic variation in pathogen virulence, a complete understanding of species decline requires the accurate identification and characterization of EIDs. We explore this issue in the Western honeybee, where increasing mortality of populations in the Northern Hemisphere has caused major concern. Specifically, we investigate the importance of genetic identity of the main suspect in mortality, deformed wing virus (DWV), in driving honeybee loss. Using laboratory experiments and a systematic field survey, we demonstrate that an emerging DWV genotype (DWV-B) is more virulent than the established DWV genotype (DWV-A) and is widespread in the landscape. Furthermore, we show in a simple model that colonies infected with DWV-B collapse sooner than colonies infected with DWV-A. We also identify potential for rapid DWV evolution by revealing extensive genome-wide recombination in vivo . The emergence of DWV-B in naive honeybee populations, including via recombination with DWV-A, could be of significant ecological and economic importance. Our findings emphasize that knowledge of pathogen genetic identity and diversity is critical to understanding drivers of species decline.

scholarly journals Possible Interactions between the NS-1 Protein and Tumor Necrosis Factor Alpha Pathways in Erythroid Cell Apoptosis Induced by Human Parvovirus B19

1999 ◽  
Vol 73 (10) ◽  
pp. 8762-8770 ◽  
Author(s):  
N. Sol ◽  
J. Le Junter ◽  
I. Vassias ◽  
J. M. Freyssinier ◽  
A. Thomas ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Parvovirus B19 ◽  
Erythroid Cell ◽  
Erythroid Cells ◽  
Necrosis Factor Alpha ◽  
Erythroid Progenitor ◽  
Apoptotic Pathways ◽  
Induced Apoptosis ◽  
Necrosis Factor

ABSTRACT Human erythroid progenitor cells are the main target cells of the human parvovirus B19 (B19), and B19 infection induces a transient erythroid aplastic crisis. Several authors have reported that the nonstructural protein 1 (NS-1) encoded by this virus has a cytotoxic effect, but the underlying mechanism of NS-1-induced primary erythroid cell death is still not clear. In human erythroid progenitor cells, we investigated the molecular mechanisms leading to apoptosis after natural infection of these cells by the B19 virus. The cytotoxicity of NS-1 was concomitantly evaluated in transfected erythroid cells. B19 infection and NS-1 expression induced DNA fragmentation characteristic of apoptosis, and the commitment of erythroid cells to undergo apoptosis was combined with their accumulation in the G2phase of the cell cycle. Since B19- and NS-1-induced apoptosis was inhibited by caspase 3, 6, and 8 inhibitors, and substantial caspase 3, 6, and 8 activities were induced by NS-1 expression, there may have been interactions between NS-1 and the apoptotic pathways of the death receptors tumor necrosis factor receptor 1 and Fas. Our results suggest that Fas-FasL interaction was not involved in NS-1- or B19-induced apoptosis in erythroid cells. In contrast, these cells were sensitized to tumor necrosis factor alpha (TNF-α)-induced apoptosis. Moreover, the ceramide level was enhanced by B19 infection and NS-1 expression. Therefore, our results suggest that there may be a connection between the respective apoptotic pathways activated by TNF-α and NS-1 in human erythroid cells.

Distinct Apoptotic Responses Imparted by c-myc and max

Blood ◽  
1998 ◽  
Vol 92 (3) ◽  
pp. 1003-1010 ◽  
Author(s):  
Chadd E. Nesbit ◽  
Saijun Fan ◽  
Hong Zhang ◽  
Edward V. Prochownik
Keyword(s):  
Cell Death ◽  
Cell Lines ◽  
Ectopic Expression ◽  
Drug Induced ◽  
Enhanced Sensitivity ◽  
Contrast Enhanced ◽  
Apoptotic Pathways ◽  
American Society ◽  
Induced Apoptosis ◽  
Cytokine Deprivation

Abstract The c-myc oncoprotein accelerates programmed cell death (apoptosis) after growth factor deprivation or pharmacological insult in many cell lines. We have shown that max, the obligate c-myc heterodimeric partner protein, also promotes apoptosis after serum withdrawal in NIH3T3 fibroblasts or cytokine deprivation in interleukin-3 (IL-3)-dependent 32D murine myeloid cells. We now show that c-myc– and max-overexpressing 32D cells differ in the nature of their apoptotic responses after IL-3 removal or treatment with chemotherapeutic compounds. In the presence of IL-3, c-myc overexpression enhances the sensitivity of 32D cells to Etoposide (Sigma, St Louis, MO), Adriamycin (Pharmacia, Columbus, OH), and Camptothecin (Sigma), whereas max overexpression increases sensitivity only to Camptothecin. Drug treatment of c-myc–overexpressing cells in the absence of IL-3 did not alter the spectrum of drug sensitivity other than to additively accelerate cell death. In contrast, enhanced sensitivity to Adriamycin, Etoposide, and Taxol (Bristol-Meyers Squibb, Princeton, NJ) was revealed in max-overexpressing cells concurrently deprived of IL-3. Differential rates of apoptosis were not strictly correlated with the ability of the drugs to promote G1 or G2/M arrest. Ectopic expression of Bcl-2 or Bcl-XL blocked drug-induced apoptosis in both cell lines. In contrast, whereas Bcl-2 blocked apoptosis in both cell lines in response to IL-3 withdrawal, Bcl-XL blocked apoptosis in max-overexpressing cells but not in c-myc–overexpressing cells. These results provide mechanistic underpinnings for the idea that c-myc and max modulate distinct apoptotic pathways. © 1998 by The American Society of Hematology.

scholarly journals L-securinine inhibits cell growth and metastasis of human androgen-independent prostate cancer DU145 cells via regulating mitochondrial and AGTR1/MEK/ERK/STAT3/PAX2 apoptotic pathways

2019 ◽  
Vol 39 (5) ◽  
Author(s):  
Dongxu Zhang ◽  
Houxian Liu ◽  
Binbin Yang ◽  
Jiasheng Hu ◽  
Yue Cheng
Keyword(s):  
Prostate Cancer ◽  
Protein Expression ◽  
Annexin V ◽  
Inhibitory Effect ◽  
Apoptotic Pathway ◽  
Growth Inhibitory ◽  
Du145 Cells ◽  
Apoptotic Pathways ◽  
Induced Apoptosis ◽  
Androgen Independent

Abstract The present study aims to evaluate the anticancer effect of L-securinine on androgen-independent prostate cancer (AIPC) DU145 cells. L-securinine (2.5, 5, and 10 μM) treatment for 24, 48 and 72 h displayed strong growth inhibitory effect on DU145 cells in a concentration and time-dependent fashion but has less toxicity toward normal androgen-dependent LNCaP cells. Hoechst 332582 staining of DU145 cells and Annexin V-FITC/ PI dual-labeling followed by flow cytometry assay identified that this growth inhibition by L-securinine would be due to the induction of apoptosis. Moreover Transwell assay revealed that L-securinine significantly inhibited the cell migration/invasion ability of DU145 cells. Furthermore, results of western blotting showed that the involvement of mitochondrial apoptotic pathway in the L-securinine-induced apoptosis of DU145 cell, as evidenced by an increase in the protein expression of Bax, cleaved caspase-9, cleaved caspase-3, cytosolic cytochrome c, and cleaved PARP, together with a unchanged cleaved caspase-8 and decreased Bcl-2 protein expression. Also, L-securinine-induced antimetastatic activity in DU145 cells was associated with decreased protein expression of MMP-2 and MMP-9 and concurrent reduction of VEGF. In addition, further studies revealed that L-securinine may inhibit the protein expression of AGTR1, p-MEK1/2, p-ERK1/2, p-STAT3, PAX2, and p-PAX2, while the expression of ERK1/2, MEK1/2, and STAT3 protein retains intact. These findings suggest that L-securinine may be a promising chemopreventive agent against AIPC.

Effet radiosensibilisateur de l'acide linoléique conjugué chez les cellules cancéreuses du sein MCF-7 et MDA-MB-231

2004 ◽  
Vol 82 (2) ◽  
pp. 94-102 ◽  
Author(s):  
Geneviève Drouin ◽  
Annie Douillette ◽  
Pierre Lacasse ◽  
Benoit Paquette
Keyword(s):  
Breast Cancer ◽  
Linoleic Acid ◽  
Cancer Cells ◽  
Conjugated Linoleic Acid ◽  
Breast Cancer Cells ◽  
Fold Increase ◽  
Breast Cancer Cell Lines ◽  
Apoptotic Pathways ◽  
Induced Apoptosis ◽  
Mcf 7

Apoptotic pathways in breast cancer cells are frequently altered, reducing the efficiency of radiotherapy. Conjugated linoleic acid (CLA), known to trigger apoptosis, was tested as radiosensitizer in breast cancer cells MCF-7 and MDA-MB-231. The CLA-mix, made up of the isomers CLA-9cis 11trans and CLA-10trans 12cis, was compared to three purified isomers, i.e., the CLA-9cis 11cis, CLA-9cis 11trans, and CLA-10trans 12cis. Using the apoptotic marker YO-PRO®-1, the CLA-9cis 11cis at 50 µmol/L turned out to be the best apoptotic inducer leading to a 10-fold increase in MCF-7 cells and a 2,5-fold increase in MDA-MB-231 cells, comparatively to the CLA-mix. Contrary to previous studies on colorectal and prostate cancer cells, CLA-10trans 12cis does not lead to an apoptotic response on breast cancer cell lines MCF-7 and MDA-MB-231. Our results also suggest that the main components of the CLA-mix (CLA-9cis 11trans and CLA-10trans 12cis) are not involved in the induction of apoptosis in the breast cancer cells studied. A dose of 5 Gy did not induce apoptosis in MCF-7 and MDA-MB-231 cells. The addition of CLA-9cis 11cis or CLA-mix has allowed us to observe a radiation-induced apoptosis, with the CLA-9cis 11cis being about 8-fold better than the CLA-mix. CLA-9cis 11cis turned out to be the best radiosensitizer, although the isomers CLA-9cis 11trans and CLA-10trans 12cis have also reduced the cell survival following irradiation, but using a mechanism not related to apoptosis. In conclusion, the radiosensitizing property of CLA-9cis 11cis supports its potential as an agent to improve radiotherapy against breast carcinoma.Key words: breast cancer, conjugated linoleic acid (CLA), radiotherapy, apoptosis.

scholarly journals Novel Chrysin-De-Allyl PAC-1 Hybrid Analogues as Anticancer Compounds: Design, Synthesis, and Biological Evaluation

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3063
Author(s):  
Buthina A. Al-Oudat ◽  
Hariteja Ramapuram ◽  
Saloni Malla ◽  
Suaad A. Audat ◽  
Noor Hussein ◽  
...  
Keyword(s):  
Mammary Epithelial Cells ◽  
Biological Evaluation ◽  
Mammary Epithelial ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Anticancer Compounds ◽  
Design Synthesis ◽  
Apoptotic Pathways ◽  
Induced Apoptosis

New chrysin-De-allyl-Pac-1 hybrid analogues, tethered with variable heterocyclic systems (4a–4o), were rationally designed and synthesized. The target compounds were screened for in vitro antiproliferative efficacy in the triple-negative breast cancer (TNBC) cell line, MDA-MB-231, and normal human mammary epithelial cells (HMECs). Two compounds, 4g and 4i, had the highest efficacy and selectivity towards MDA-MB-231 cells, and thus, were further evaluated by mechanistic experiments. The results indicated that both compounds 4g and 4i induced apoptosis by (1) inducing cell cycle arrest at the G2 phase in MDA-MB-231 cells, and (2) activating the intrinsic apoptotic pathways in a concentration-dependent manner. Physicochemical characterizations of these compounds suggested that they can be further optimized as potential anticancer compounds for TNBC cells. Overall, our results suggest that 4g and 4i could be suitable leads for developing novel compounds to treat TNBC.

Differential protective effects of Bcl-xL and Bcl-2 on apoptotic liver injury in transgenic mice

1999 ◽  
Vol 277 (3) ◽  
pp. G702-G708 ◽  
Author(s):  
Alix de la Coste ◽  
Monique Fabre ◽  
Nathalie McDonell ◽  
Arlette Porteu ◽  
Helène Gilgenkrantz ◽  
...  
Keyword(s):  
Liver Injury ◽  
Transgenic Mice ◽  
Fas Ligand ◽  
Dependent Manner ◽  
Protective Effects ◽  
Tnf Α ◽  
Apoptotic Pathways ◽  
Induced Apoptosis ◽  
Factor Α

Fas ligand (CD95L) and tumor necrosis factor-α (TNF-α) are pivotal inducers of hepatocyte apoptosis. Uncontrolled activation of these two systems is involved in several forms of liver injury. Although the broad antiapoptotic action of Bcl-2 and Bcl-xL has been clearly established in various apoptotic pathways, their ability to inhibit the Fas/CD95- and TNF-α-mediated apoptotic signal has remained controversial. We have demonstrated that the expression of BCL-2 in hepatocytes protects them against Fas-induced fulminant hepatitis in transgenic mice. The present study shows that transgenic mice overexpressing[Formula: see text]in hepatocytes are also protected from Fas-induced apoptosis in a dose-dependent manner. Bcl-xL and Bcl-2 were protective without any change in the level of endogenous[Formula: see text]or Bax and inhibited hepatic caspase-3-like activity. In vivo injection of TNF-α caused massive apoptosis and death only when transcription was inhibited. Under these conditions,[Formula: see text]mice were partially protected from liver injury and death but PK-BCL-2 mice were not. A similar differential protective effect of Bcl-xL and Bcl-2 transgenes was observed when Fas/CD95 was activated and transcription blocked. These results suggest that apoptosis triggered by activation of both Fas/CD95 and TNF-α receptors is to some extent counteracted by the transcription-dependent protective effects, which are essential for the antiapoptotic activity of Bcl-2 but not of Bcl-xL. Therefore, Bcl-xL and Bcl-2 appear to have different antiapoptotic effects in the liver whose characterization could facilitate their use to prevent the uncontrolled apoptosis of hepatocytes.

scholarly journals Poliovirus Protein 3A Inhibits Tumor Necrosis Factor (TNF)-Induced Apoptosis by Eliminating the TNF Receptor from the Cell Surface

2001 ◽  
Vol 75 (21) ◽  
pp. 10409-10420 ◽  
Author(s):  
Nickolay Neznanov ◽  
Anna Kondratova ◽  
Konstantin M. Chumakov ◽  
Brigitte Angres ◽  
Bakhyt Zhumabayeva ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Cell Surface ◽  
Protein Trafficking ◽  
Tumor Necrosis ◽  
Viral Infections ◽  
Brefeldin A ◽  
Tnf Receptor ◽  
Apoptotic Pathways ◽  
Induced Apoptosis ◽  
Necrosis Factor

ABSTRACT Viral infections often trigger host defensive reactions by activating intrinsic (intracellular) and extrinsic (receptor-mediated) apoptotic pathways. Poliovirus is known to encode an antiapoptotic function(s) suppressing the intrinsic pathway. Here, the effect of poliovirus nonstructural proteins on cell sensitivity to tumor necrosis factor (TNF)-induced (i.e., receptor-mediated) apoptosis was studied. This sensitivity is dramatically enhanced by the viral proteinase 2A, due, most likely, to inhibition of cellular translation. On the other hand, cells expressing poliovirus noncapsid proteins 3A and 2B exhibit strong TNF resistance. Expression of 3A neutralizes the proapoptotic activity of 2A and results in a specific suppression of TNF signaling, including the lack of activation of NF-κB, due to elimination of the TNF receptor from the cell surface. In agreement with this, poliovirus infection results in a dramatic decrease in TNF receptor abundance on the surfaces of infected cells as early as 4 h postinfection. Poliovirus proteins that confer resistance to TNF interfere with endoplasmic reticulum-Golgi protein trafficking, and their effect on TNF signaling can be imitated by brefeldin A, suggesting that the mechanism of poliovirus-mediated resistance to TNF is a result of aberrant TNF receptor trafficking.

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