scholarly journals Genome-wide characterization of SARS-CoV-2 cytopathogenic proteins in the search of antiviral targets

2021 ◽  
Author(s):  
Jiantao Zhang ◽  
Qi Li ◽  
Ruth S. Cruz Cosme ◽  
Vladimir Gerzanich ◽  
Qiyi Tang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Mammalian Cells ◽  
Cellular Proliferation ◽  
Nf Kappa B ◽  
Cytopathic Effects ◽  
Genome Wide ◽  
Antiviral Targets ◽  
Apoptosis And Necrosis

Therapeutic inhibition of critical viral functions is important for curtailing coronavirus disease-2019 (COVID-19). We sought to identify antiviral targets through genome-wide characterization of SARS-CoV-2 proteins that are crucial for viral pathogenesis and that cause harmful cytopathic effects. All twenty-nine viral proteins were tested in a fission yeast cell-based system using inducible gene expression. Twelve proteins including eight non-structural proteins (NSP1, NSP3, NSP4, NSP5, NSP6, NSP13, NSP14 and NSP15) and four accessory proteins (ORF3a, ORF6, ORF7a and ORF7b) were identified that altered cellular proliferation and integrity, and induced cell death. Cell death correlated with the activation of cellular oxidative stress. Of the twelve proteins, ORF3a was chosen for further study in mammalian cells. In human pulmonary and kidney epithelial cells, ORF3a induced cellular oxidative stress associated with apoptosis and necrosis, and caused activation of pro-inflammatory response with production of the cytokines TNF-alpha, IL-6, and IFN-beta1, possibly through the activation of NF-kappa B. To further characterize the mechanism, we tested a natural ORF3a Beta variant, Q57H, and a mutant with deletion of the highly conserved residue, deltaG188. Compared to wild type ORF3a, the delataG188 variant yielded more robust activation of cellular oxidative stress, cell death, and innate immune response. Since cellular oxidative stress and inflammation contribute to cell death and tissue damage linked to the severity of COVID-19, our findings suggest that ORF3a is a promising, novel therapeutic target against COVID-19.

Tobacco smoke induces both apoptosis and necrosis in mammalian cells: differential effects of HSP70

1998 ◽  
Vol 275 (4) ◽  
pp. L771-L779 ◽  
Author(s):  
Muriel Vayssier ◽  
Nathalie Banzet ◽  
Dominique François ◽  
Kerstin Bellmann ◽  
Barbara S. Polla
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Tobacco Smoke ◽  
Mammalian Cells ◽  
Cell Injury ◽  
Hsp70 Expression ◽  
Protective Effects ◽  
Low Concentrations ◽  
Induced Apoptosis ◽  
Apoptosis And Necrosis

Tobacco smoke (TS) has been implicated as a major risk factor in human pulmonary diseases including cancer. In this study, we used TS as a model of oxidative stress. TS-mediated oxidative stress has been shown to induce protein oxidation, DNA damage, and cell death. Here we investigated, in human and rodent cell lines, whether TS induces cell death by apoptosis or by necrosis. As described for classic oxidants, TS induced apoptosis at low concentrations and necrosis at higher concentrations. We have previously described the induction of heat shock (HS) protein (HSP) (in particular, HSP70) in human monocytes exposed to TS. HSP70 is implicated in the regulation of cell injury and cell death and, in particular, modulates apoptosis, as does the antiapoptotic oncoprotein Bcl-2. At both apoptotic and necrotic concentrations, TS induced a dose-dependent HSP70 expression, whereas Bcl-2 was induced only at necrotic concentrations. TS- or HS-induced HSP had no protective effects either on apoptosis or on necrosis, but HSP70 overexpression prevented TS-induced necrosis and consequently led to increased apoptosis. These results might reconcile the apparently contradictory data previously reported on the effects of HSP on apoptosis.

scholarly journals Overexpression of Transcripts Coding for Renin-b but Not for Renin-a Reduce Oxidative Stress and Increase Cardiomyoblast Survival under Starvation Conditions

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1204
Author(s):  
Heike Wanka ◽  
Philipp Lutze ◽  
Alexander Albers ◽  
Janine Golchert ◽  
Doreen Staar ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
B Cells ◽  
Apoptotic Cell ◽  
Renin Angiotensin System ◽  
Glucose Deprivation ◽  
Protective Effects ◽  
Glucose Depletion ◽  
A Cells ◽  
Apoptosis And Necrosis

A stimulated renin-angiotensin system is known to promote oxidative stress, apoptosis, necrosis and fibrosis. Renin transcripts (renin-b; renin-c) encoding a cytosolic renin isoform have been discovered that may in contrast to the commonly known secretory renin (renin-a) exert protective effects Here, we analyzed the effect of renin-a and renin-b overexpression in H9c2 cardiomyoblasts on apoptosis and necrosis as well as on potential mechanisms involved in cell death processes. To mimic ischemic conditions, cells were exposed to glucose starvation, anoxia or combined oxygen–glucose deprivation (OGD) for 24 h. Under OGD, control cells exhibited markedly increased necrotic and apoptotic cell death accompanied by enhanced ROS accumulation, loss of mitochondrial membrane potential and decreased ATP levels. The effects of OGD on necrosis were exaggerated in renin-a cells, but markedly diminished in renin-b cells. However, with respect to apoptosis, the effects of OGD were almost completely abolished in renin-b cells but interestingly also moderately diminished in renin-a cells. Under glucose depletion we found opposing responses between renin-a and renin-b cells; while the rate of necrosis and apoptosis was aggravated in renin-a cells, it was attenuated in renin-b cells. Based on our results, strategies targeting the regulation of cytosolic renin-b as well as the identification of pathways involved in the protective effects of renin-b may be helpful to improve the treatment of ischemia-relevant diseases.

scholarly journals A genome-wide RNAi screen reveals multiple regulators of caspase activation

2007 ◽  
Vol 179 (4) ◽  
pp. 619-626 ◽  
Author(s):  
Caroline H. Yi ◽  
Dodzie K. Sogah ◽  
Michael Boyce ◽  
Alexei Degterev ◽  
Dana E. Christofferson ◽  
...  
Keyword(s):  
Cell Death ◽  
Mammalian Cells ◽  
Caspase Activation ◽  
Functional Conservation ◽  
Cellular Processes ◽  
Regulatory Circuits ◽  
Genome Wide ◽  
A Genome ◽  
Dependent Cell ◽  
Functionally Diverse

Apoptosis is an evolutionally conserved cellular suicide mechanism that can be activated in response to a variety of stressful stimuli. Increasing evidence suggests that apoptotic regulation relies on specialized cell death signaling pathways and also integrates diverse signals from additional regulatory circuits, including those of cellular homeostasis. We present a genome-wide RNA interference screen to systematically identify regulators of apoptosis induced by DNA damage in Drosophila melanogaster cells. We identify 47 double- stranded RNA that target a functionally diverse set of genes, including several with a known function in promoting cell death. Further characterization uncovers 10 genes that influence caspase activation upon the removal of Drosophila inhibitor of apoptosis 1. This set includes the Drosophila initiator caspase Dronc and, surprisingly, several metabolic regulators, a candidate tumor suppressor, Charlatan, and an N-acetyltransferase, ARD1. Importantly, several of these genes show functional conservation in regulating apoptosis in mammalian cells. Our data suggest a previously unappreciated fundamental connection between various cellular processes and caspase-dependent cell death.

scholarly journals Preconditioning and Acute Effects of Flavonoids in Protecting Cardiomyocytes from Oxidative Cell Death

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Masoumeh Akhlaghi ◽  
Brian Bandy
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Relative Effectiveness ◽  
Epigallocatechin Gallate ◽  
Short Term ◽  
Higher Doses

While flavonoids can reportedly protect against cardiac ischemia-reperfusion injury, the relative effectiveness of different flavonoids and the mechanisms involved are unclear. We compared protection by different flavonoids using rat embryonic ventricular H9c2 cells subjected to simulated ischemia-reperfusion (IR) and totert-butyl hydroperoxide (t-buOOH). Characterization of the IR model showed the relative contributions of glucose, serum, and oxygen deprivation to cell death. With long-term (2-3 day) pretreatment before IR the best protection was given by catechin, epigallocatechin gallate, proanthocyanidins, and ascorbate, which protected at all doses. Quercetin protected (34%) at 5 μM but was cytotoxic at higher doses. Cyanidin protected mildly (10–15%) at 5 and 20 μM, while delphinidin had no effect at 5 μM and was cytotoxic at higher doses. Comparing long-term and acute protection by catechin, a higher concentration was needed for benefit with acute (1 hr) pretreatment. With a pure oxidative stress (t-buOOH) only quercetin significantly protected with 3-day pretreatment, while with short-term (1 h) pretreatments protection was best with quercetin and epigallocatechin gallate. The results suggest catechins to be especially useful as IR preconditioning agents, while quercetin and epigallocatechin gallate may be the most protective acutely in situations of oxidative stress.

scholarly journals Depletion of ATP and Oxidative Stress Underlie Zinc-Induced Cell Injury

2007 ◽  
Vol 50 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Emil Rudolf
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Cell Death ◽  
Nadph Oxidase ◽  
Cell Injury ◽  
Atp Depletion ◽  
Atp Production ◽  
Apoptosis And Necrosis ◽  
Positive Effect ◽  
And Oxidative Stress

The mechanisms of cell injury resulting in a special type of cell death combining the features of apoptosis and necrosis were examined in Hep-2 cells exposed to 300 μM zinc sulfate during 24h. Acute exposure to zinc induced a rapid rise in metallothionein levels and increased oxidative stress occurring in the absence of a significant early ATP depletion. Accentuated ATP loss and elevated levels of superoxide at later treatment intervals (12h and longer) were present along with increased DNA damage. Manipulation with ATP production and inhibition of NADPH oxidase had a positive effect on zinc-related increase in oxidative stress and influenced the observed type of cell death. These results suggest that Hep-2 cells acutely exposed to zinc increase intracellular labile zinc stores and over express metalothioneins. Elevated production of peroxides in zinc-treated cells is at later treatment intervals accompanied by an increase in superoxide levels, possibly by activation of NADPH oxidase, DNA damage and severe ATP loss. Prevention of critical ATP depletion and, in particular, inhibition of oxidative stress attenuates zinc-mediated cell injury and stimulates apoptosis-like phenotype in exposed cells.

scholarly journals Genome-wide transcriptional responses of iron-starvedChlamydia trachomatisreveal prioritization of metabolic precursor synthesis over protein translation

2017 ◽  
Author(s):  
Amanda J. Brinkworth ◽  
Mark R. Wildung ◽  
Rey A. Carabeo
Keyword(s):  
Oxidative Stress ◽  
Dna Repair ◽  
Chlamydia Trachomatis ◽  
Rapid Growth ◽  
Mammalian Cells ◽  
Protein Translation ◽  
Specific Response ◽  
Iron Starvation ◽  
Transcriptional Responses ◽  
Genome Wide

ABSTRACTIron is essential for growth and development ofChlamydia. Its long-term starvation in cultured mammalian cells leads to production of aberrant non-infectious chlamydial forms, also known as persistence. Immediate transcriptional responses to iron limitation have not been characterized, leaving a knowledge gap of howChlamydiaregulates its response to changes in iron availability. We used the fast-chelating agent 2,2’-Bipyridyl (BPDL) to homogeneously starveChlamydia trachomatisserovar L2 of iron, starting at 6 or 12h post-infection. Immediate transcriptional responses were monitored after only 3 or 6h of BPDL-treatment, well before formation of aberrantChlamydia.The first genome-wide transcriptional response ofC. trachomatisto iron-starvation was subsequently determined utilizing RNA-sequencing. Only 7% and 8% of the genome was differentially expressed in response to iron-starvation at early and mid-stages of development, respectively. Biological pathway analysis revealed an overarching theme. Synthesis of macromolecular precursors (deoxynucleotides, amino acids, charged tRNAs, and acetyl-coA) was up-regulated, while energy-expensive processes (ABC transport and translation) were down-regulated. A large fraction of differentially down-regulated genes are involved in translation, including ribosome assembly, initiation and termination factors, which could be analogous to the translation down-regulation triggered by stress in other prokaryotes during stringent responses. Additionally, transcriptional up-regulation of DNA repair, oxidative stress, and tryptophan salvage genes reveals a possible coordination of responses to multiple antimicrobial and immunological insults. These responses of replicative-phaseChlamydiato iron-starvation indicate a prioritization of survival over replication, enabling the pathogen to “stock the pantry” with ingredients needed for rapid growth once optimal iron levels are restored.IMPORTANCEBy utilizing an experimental approach that monitors the immediate global response ofChlamydia trachomatisto iron-starvation, clues to long-standing questions inChlamydiabiology are revealed, including howChlamydiaadapts to this stress. We determined that this pathogen initiates a transcriptional program that prioritizes replenishment of nutrient stores over replication, possibly in preparation for rapid growth once optimal iron levels are restored. Transcription of genes for biosynthesis of metabolic precursors was generally up-regulated, while those involved in multiple steps of translation were down-regulated. We also observed an increase in transcription of genes involved in DNA repair and neutralizing oxidative stress, indicating thatChlamydiaemploys an “all-or-nothing” strategy. Its small genome limits its ability to tailor a specific response to a particular stress. Therefore, the “all-or-nothing” strategy may be the most efficient way of surviving within the host, where the pathogen likely encounters multiple simultaneous immunological and nutritional insults.

scholarly journals TAK1 Mediates ROS Generation Triggered by the Specific Cephalosporins through Noncanonical Mechanisms

2020 ◽  
Vol 21 (24) ◽  
pp. 9497
Author(s):  
Midori Suzuki ◽  
Yukino Asai ◽  
Tomohiro Kagi ◽  
Takuya Noguchi ◽  
Mayuka Yamada ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Mammalian Cells ◽  
Transforming Growth Factor ◽  
Microscopic Analysis ◽  
Transforming Growth Factor Β ◽  
Nuclear Factor Κb ◽  
Mitogen Activated Protein Kinase ◽  
Ros Generation ◽  
Mitogen Activated Protein

It is known that a wide variety of antibacterial agents stimulate generation of reactive oxygen species (ROS) in mammalian cells. However, its mechanisms are largely unknown. In this study, we unexpectedly found that transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) is involved in the generation of mitochondrial ROS (mtROS) initiated by cefotaxime (CTX), one of specific antibacterial cephalosporins that can trigger oxidative stress-induced cell death. TAK1-deficient macrophages were found to be sensitive to oxidative stress-induced cell death stimulated by H2O2. Curiously, however, TAK1-deficient macrophages exhibited strong resistance to oxidative stress-induced cell death stimulated by CTX. Microscopic analysis revealed that CTX-induced ROS generation was overridden by knockout or inhibition of TAK1, suggesting that the kinase activity of TAK1 is required for CTX-induced ROS generation. Interestingly, pharmacological blockade of the TAK1 downstream pathways, such as nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways, did not affect the CTX-induced ROS generation. In addition, we observed that CTX promotes translocation of TAK1 to mitochondria. Together, these observations suggest that mitochondrial TAK1 mediates the CTX-induced mtROS generation through noncanonical mechanisms. Thus, our data demonstrate a novel and atypical function of TAK1 that mediates mtROS generation triggered by the specific cephalosporins.

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