scholarly journals Bacterial DNA damage effectors in host cells

2018 ◽  
Vol 16 (3) ◽  
pp. 26-36
Author(s):  
Vladimir G. Druzhinin ◽  
Elizaveta D. Baranova ◽  
Vladislav Yu. Buslaev ◽  
Lyudmila V. Matskova ◽  
Alina V. Tolstikova
Keyword(s):  
Dna Damage ◽  
Bacterial Species ◽  
Host Cells ◽  
Host Organism ◽  
Mutation Process ◽  
Bacterial Dna ◽  
Bacterial Microbiota ◽  
Repair Efficiency ◽  
Infected Cells ◽  
Genotoxic Action

The microbiota has a significant, and sometimes decisive, effect on the host's homeostasis. The results of recent metagenomic studies confirm the importance of microbiota in maintaining health or its impact on the development of acute, chronic and neoplastic diseases. One of the important aspects of microbiota exposure is the ability of many bacterial species to induce mutations or modulate a mutation process in the cells of the host organism. This review summarizes the main experimental data revealing various mechanisms of genotoxic action of a bacterial microbiota, including direct damage to the DNA structure, induction of oxidative stress, delay in replication, and a decrease in repair efficiency. It is emphasized that bacteria use different strategies to ensure their own survival and replication, including. by suppressing the repair of host cell DNA, by promoting the survival of infected cells, despite the presence of DNA damage therein.

scholarly journals DNA double-strand breaks in the Toxoplasma gondii-infected cells by the action of reactive oxygen species

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Haohan Zhuang ◽  
Chaoqun Yao ◽  
Xianfeng Zhao ◽  
Xueqiu Chen ◽  
Yimin Yang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Toxoplasma Gondii ◽  
Double Strand Breaks ◽  
Host Cells ◽  
Oxygen Species ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Damage Response ◽  
Infected Cells

Abstract Background Toxoplasma gondii is an obligate parasite of all warm-blooded animals around the globe. Once infecting a cell, it manipulates the host’s DNA damage response that is yet to be elucidated. The objectives of the present study were three-fold: (i) to assess DNA damages in T. gondii-infected cells in vitro; (ii) to ascertain causes of DNA damage in T. gondii-infected cells; and (iii) to investigate activation of DNA damage responses during T. gondii infection. Methods HeLa, Vero and HEK293 cells were infected with T. gondii at a multiplicity of infection (MOI) of 10:1. Infected cells were analyzed for a biomarker of DNA double-strand breaks (DSBs) γH2AX at 10 h, 20 h or 30 h post-infection using both western blot and immunofluorescence assay. Reactive oxygen species (ROS) levels were measured using 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA), and ROS-induced DNA damage was inhibited by a ROS inhibitor N-acetylcysteine (NAC). Lastly, DNA damage responses were evaluated by detecting the active form of ataxia telangiectasia mutated/checkpoint kinase 2 (ATM/CHK2) by western blot. Results γH2AX levels in the infected HeLa cells were significantly increased over time during T. gondii infection compared to uninfected cells. NAC treatment greatly reduced ROS and concomitantly diminished γH2AX in host cells. The phosphorylated ATM/CHK2 were elevated in T. gondii-infected cells. Conclusions Toxoplasma gondii infection triggered DNA DSBs with ROS as a major player in host cells in vitro. It also activated DNA damage response pathway ATM/CHK2. Toxoplasma gondii manages to keep a balance between survival and apoptosis of its host cells for the benefit of its own survival.

scholarly journals SARS-CoV-2 triggers DNA damage response in Vero E6 cells

2021 ◽  
Author(s):  
Joshua Victor ◽  
Jamie Deutsch ◽  
Annalis Whitaker ◽  
Erica N. Lamkin ◽  
Anthony March ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Host Cells ◽  
Kidney Cells ◽  
The Novel ◽  
African Green Monkey Kidney ◽  
Downstream Effector ◽  
Damage Response ◽  
Green Monkey ◽  
Infected Cells

AbstractThe novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus responsible for the current COVID-19 pandemic and has now infected more than 200 million people with more than 4 million deaths globally. Recent data suggest that symptoms and general malaise may continue long after the infection has ended in recovered patients, suggesting that SARS-CoV-2 infection has profound consequences in the host cells. Here we report that SARS-CoV-2 infection can trigger a DNA damage response (DDR) in African green monkey kidney cells (Vero E6). We observed a transcriptional upregulation of the Ataxia telangiectasia and Rad3 related protein (ATR) in infected cells. In addition, we observed enhanced phosphorylation of CHK1, a downstream effector of the ATR DNA damage response, as well as H2AX. Strikingly, SARS-CoV-2 infection lowered the expression of TRF2 shelterin-protein complex, and reduced telomere lengths in infected Vero E6 cells. Thus, our observations suggest SARS-CoV-2 may have pathological consequences to host cells beyond evoking an immunopathogenic immune response.

scholarly journals Hepatitis C Virus Downregulates Ubiquitin-Conjugating Enzyme E2S Expression To Prevent Proteasomal Degradation of NS5A, Leading to Host Cells More Sensitive to DNA Damage

2018 ◽  
Vol 93 (2) ◽  
Author(s):  
Hang T. Pham ◽  
Tram T. T. Nguyen ◽  
Lap P. Nguyen ◽  
Sang-Seop Han ◽  
Yun-Sook Lim ◽  
...  
Keyword(s):  
Dna Damage ◽  
Antiviral Activity ◽  
Host Cells ◽  
Protein Homeostasis ◽  
Viral Propagation ◽  
Ns5a Protein ◽  
Ubiquitin Conjugating Enzyme ◽  
Infected Cells ◽  
Dependent Pathway ◽  
Conjugating Enzyme

ABSTRACT Hepatitis C virus (HCV) infection may cause chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV exploits cellular machineries to establish persistent infection. We demonstrate here that ubiquitin-conjugating enzyme E2S (UBE2S), a member of the ubiquitin-conjugating enzyme family (E2s), was downregulated by endoplasmic reticulum stress caused by HCV in Huh7 cells. UBE2S interacted with domain I of HCV NS5A and degraded NS5A protein through the Lys11-linked proteasome-dependent pathway. Overexpression of UBE2S suppressed viral propagation, while depletion of UBE2S expression increased viral infectivity. Enzymatically inactive UBE2S C95A mutant exerted no antiviral activity, suggesting that ubiquitin-conjugating enzymatic activity was required for the suppressive role of UBE2S. Chromatin ubiquitination plays a crucial role in the DNA damage response. We showed that the levels of UBE2S and Lys11 chains bound to the chromatin were markedly decreased in the context of HCV replication, rendering HCV-infected cells more sensitive to DNA damage. These data suggest that HCV counteracts antiviral activity of UBE2S to optimize viral propagation and may contribute to HCV-induced liver pathogenesis. IMPORTANCE Protein homeostasis is essential to normal cell function. HCV infection disturbs the protein homeostasis in the host cells. Therefore, host cells exert an anti-HCV activity in order to maintain normal cellular metabolism. We showed that UBE2S interacted with HCV NS5A and degraded NS5A protein through the Lys11-linked proteasome-dependent pathway. However, HCV has evolved to overcome host antiviral activity. We demonstrated that the UBE2S expression level was suppressed in HCV-infected cells. Since UBE2S is an ubiquitin-conjugating enzyme and this enzyme activity is involved in DNA damage repair, HCV-infected cells are more sensitive to DNA damage, and thus UBE2S may contribute to viral oncogenesis.

scholarly journals Identification of New Secreted Effectors in Salmonella enterica Serovar Typhimurium

2005 ◽  
Vol 73 (10) ◽  
pp. 6260-6271 ◽  
Author(s):  
Kaoru Geddes ◽  
Micah Worley ◽  
George Niemann ◽  
Fred Heffron
Keyword(s):  
Type Iii Secretion ◽  
Salmonella Enterica ◽  
Bacterial Species ◽  
Effector Proteins ◽  
Host Cells ◽  
Secretion Systems ◽  
Cell Cytoplasm ◽  
Type Iii ◽  
Serovar Typhimurium ◽  
Infected Cells

ABSTRACTA common theme in bacterial pathogenesis is the secretion of bacterial products that modify cellular functions to overcome host defenses. Gram-negative bacterial pathogens use type III secretion systems (TTSSs) to inject effector proteins into host cells. The genes encoding the structural components of the type III secretion apparatus are conserved among bacterial species and can be identified by sequence homology. In contrast, the sequences of secreted effector proteins are less conserved and are therefore difficult to identify. A strategy was developed to identify virulence factors secreted bySalmonella entericaserovar Typhimurium into the host cell cytoplasm. We constructed a transposon, which we refer to as mini-Tn5-cycler, to generate translational fusions betweenSalmonellachromosomal genes and a fragment of the calmodulin-dependent adenylate cyclase gene derived fromBordetella pertussis(cyaA′). In-frame fusions to bacterial proteins that are secreted into the eukaryotic cell cytoplasm were identified by high levels of cyclic AMP in infected cells. The assay was sufficiently sensitive that a single secreted fusion could be identified among several hundred that were not secreted. This approach identified three new effectors as well as seven that have been previously characterized. A deletion of one of the new effectors,steA(Salmonellatranslocated effector A), attenuated virulence. In addition, SteA localizes to thetrans-Golgi network in both transfected and infected cells. This approach has identified new secreted effector proteins inSalmonellaand will likely be useful for other organisms, even those in which genetic manipulation is more difficult.

scholarly journals DNA Double Strand Breaks in the Toxoplasma Gondii-Infected Cells by the Action of Reactive Oxygen Species

2020 ◽  
Author(s):  
Haohan Zhuang ◽  
Chaoqun Yao ◽  
Xianfeng Zhao ◽  
Yi Yang ◽  
Xueqiu Chen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Double Strand Breaks ◽  
Host Cells ◽  
Oxygen Species ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Damage Response ◽  
Infected Cells

Abstract Background: Toxoplasma gondii (T. gondii) is an obligate parasite of the warm-blooded animals with a worldwide distribution. Once having entered a host cell, it manipulates host’s DNA damage response that is yet to be investigated. The objectives of the present study were three-fold: 1) to assess DNA damages in T. gondii-infected cells in vitro; 2) to ascertain sources causing DNA damage in T. gondii-infected cells; 3) to investigate activation of DNA damage response during T. gondii infection.Methods: HeLa, Vero and HEK293 cells were infected with T. gondii at multiplicity of infection (MOI) of 10:1. Infected cells at 10 h, 20 h or 30 h post infection were analyzed for a DNA double strand breaks (DSBs) biomarker γH2AX using Western blot and immunofluorescence assay. Reactive oxygen species (ROS) levels were examined using 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA), and the impact of ROS on DNA damage was assessed by inhibition using a ROS inhibitor N-acetylcysteine (NAC). Lastly, DNA damage response in these T. gondii-infected cells was evaluated by detecting the expression of active form of ataxia telangiectasia mutated/checkpoint kinase 2 (ATM/CHK2) with Western blot. Results: Compared to uninfected cells, γH2AX expression in the infected HeLa cells at 10 h, 20 h, and 30 h was increased over time during T. gondii infection. NAC treatment reduced ROS level in host cells and significantly decreased the expression of γH2AX. Expression of phosphorylated ATM/CHK2 was elevated in T. gondii-infected cells.Conclusion: T. gondii infection triggered DNA DSBs with ROS as a major player in host cells in vitro. It also concomitantly activated DNA damage response pathway ATM/CHK2. T. gondii struggles a balance between survival and apoptosis of its host cells for the benefit of its own survival.

scholarly journals DNA damage and oxidative stress in human cells infected by Trypanosoma cruzi

2021 ◽  
Vol 17 (4) ◽  
pp. e1009502
Author(s):  
Pilar T. V. Florentino ◽  
Davi Mendes ◽  
Francisca Nathalia L. Vitorino ◽  
Davi J. Martins ◽  
Julia P. C. Cunha ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Dna Repair ◽  
Trypanosoma Cruzi ◽  
Host Cell ◽  
Dna Lesions ◽  
Host Cells ◽  
Antioxidant Defenses ◽  
Related Factor ◽  
Infected Cells

Trypanosoma cruzi is the etiologic agent of Chagas’ disease. Infected cells with T. cruzi activate several responses that promote unbalance of reactive oxygen species (ROS) that may cause DNA damage that activate cellular responses including DNA repair processes. In this work, HeLa cells and AC16 human cardiomyocyte cell line were infected with T. cruzi to investigate host cell responses at genome level during parasites intracellular life cycle. In fact, alkaline sensitive sites and oxidized DNA bases were detected in the host cell genetic material particularly in early stages of infection. These DNA lesions were accompanied by phosphorylation of the histone H2Ax, inducing γH2Ax, a marker of genotoxic stress. Moreover, Poly [ADP-ribose] polymerase) and 8-oxoguanine glycosylase (OGG1) are recruited to host cell nuclei, indicating activation of the DNA repair process. In infected cells, chromatin-associated proteins are carbonylated, as a possible consequence of oxidative stress and the nuclear factor erythroid 2–related factor 2 (NRF2) is induced early after infection, suggesting that the host cell antioxidant defenses are activated. However, at late stages of infection, NRF2 is downregulated. Interestingly, host cells pretreated with glutathione precursor, N-acetyl cysteine, NRF2 activator (Sulforaphane), and also Benznidonazol (BNZ) reduce parasite burst significantly, and DNA damage. These data indicate that the balance of oxidative stress and DNA damage induction in host cells may play a role during the process of infection itself, and interference in these processes may hamper T. cruzi infection, revealing potential target pathways for the therapy support.

DIVERSITY OF CULTURABLE BACTERIAL MICROBIOTA OF THE Eisenia foetida DIGESTIVE TRACT

2018 ◽  
Vol 41 (3) ◽  
pp. 255-264 ◽  
Author(s):  
J. Abraham Pérez-Pérez ◽  
David Espinosa-Victoria ◽  
Hilda V. Silva-Rojas ◽  
Lucía López-Reyes
Keyword(s):  
Bacterial Diversity ◽  
Digestive Tract ◽  
Bacterial Species ◽  
Brain Heart Infusion ◽  
Rrna Gene ◽  
Eisenia Foetida ◽  
Bacterial Isolates ◽  
Bacterial Microbiota ◽  
Decomposition Of Organic Matter ◽  
Earthworm Gut

Bacteria are an unavoidable component of the natural earthworm diet; thus, bacterial diversity in the earthworm gut is directly linked to decomposition of organic matter and development of the surrounding plants. The aim of this research was to isolate and to identify biochemically and molecularly the culturable bacterial microbiota of the digestive tract of Eisenia foetida. Earthworms were sourced from Instituto de Reconversión Productiva y Bioenergética (IRBIO) and Colegio de Postgraduados (COLPOS), México. Bacterial isolation was carried out on plates of Brain Heart Infusion (BHI) culture medium. Fifty six and 44 bacterial isolates were obtained from IRBIO and COLPOS, respectively. The population was composed of 44 Gram-negative and 56 Gram-positive isolates. Over 50 % of the bacterial isolates were rod-shaped cells. The 16S rRNA gene was sequenced and nine genera were identified in worms from IRBIO (Bacillus, Paenibacillus, Solibacillus, Staphylococcus, Arthrobacter, Pantoea, Stenotrophomonas, Acinetobacter and Aeromonas) and six in worms from COLPOS (Bacillus, Paenibacillus, Stenotrophomonas, Staphylococcus, Acinetobacter and Aeromonas). Bacillus was the predominant genus, with eight and six species in the oligochaetes from IRBIO and COLPOS, respectively. The most represented bacteria in the worms from both sites were Bacillus sp. and B. subtilis. The predominance of Bacillus was probably due to spore formation, a reproductive strategy that ensures survival and dispersion in the soil and oligochaetes digestive tract. The gut of E. foetida not only harbored bacterial species of agronomic importance but also species potentially pathogenic for humans (Staphylococcus warneri, Pantoea agglomerans and Stentrophomonas sp.). The larger bacterial diversity in worms from IRBIO could be due to their feeding on cattle manure, which is a rich source of bacteria.

scholarly journals Actin-Related Protein 6 (Arp6) Influences Double-Strand Break Repair in Yeast

2021 ◽  
Vol 1 (2) ◽  
pp. 225-238
Author(s):  
Mohsen Hooshyar ◽  
Daniel Burnside ◽  
Maryam Hajikarimlou ◽  
Katayoun Omidi ◽  
Alexander Jesso ◽  
...  
Keyword(s):  
Dna Damage ◽  
Chromatin Remodeling ◽  
Genetic Interaction ◽  
Interaction Analysis ◽  
Strand Break ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Dna Damaging Agents ◽  
Repair Efficiency ◽  
Chromosomal Breaks

DNA double-strand breaks (DSBs) are the most deleterious form of DNA damage and are repaired through non-homologous end-joining (NHEJ) or homologous recombination (HR). Repair initiation, regulation and communication with signaling pathways require several histone-modifying and chromatin-remodeling complexes. In budding yeast, this involves three primary complexes: INO80-C, which is primarily associated with HR, SWR1-C, which promotes NHEJ, and RSC-C, which is involved in both pathways as well as the general DNA damage response. Here we identify ARP6 as a factor involved in DSB repair through an RSC-C-related pathway. The loss of ARP6 significantly reduces the NHEJ repair efficiency of linearized plasmids with cohesive ends, impairs the repair of chromosomal breaks, and sensitizes cells to DNA-damaging agents. Genetic interaction analysis indicates that ARP6, MRE11 and RSC-C function within the same pathway, and the overexpression of ARP6 rescues rsc2∆ and mre11∆ sensitivity to DNA-damaging agents. Double mutants of ARP6, and members of the INO80 and SWR1 complexes, cause a significant reduction in repair efficiency, suggesting that ARP6 functions independently of SWR1-C and INO80-C. These findings support a novel role for ARP6 in DSB repair that is independent of the SWR1 chromatin remodeling complex, through an apparent RSC-C and MRE11-associated DNA repair pathway.

scholarly journals Monoassociation with bacterial isolates reveals the role of colonization, community complexity and abundance on locomotor behavior in larval zebrafish

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Chelsea A. Weitekamp ◽  
Allison Kvasnicka ◽  
Scott P. Keely ◽  
Nichole E. Brinkman ◽  
Xia Meng Howey ◽  
...  
Keyword(s):  
Total Concentration ◽  
Bacterial Species ◽  
Locomotor Behavior ◽  
Host Cells ◽  
Individual Species ◽  
Zebrafish Model ◽  
Associated Bacteria ◽  
Larval Zebrafish ◽  
Toxicological Studies ◽  
Community Complexity

Abstract Background Across taxa, animals with depleted intestinal microbiomes show disrupted behavioral phenotypes. Axenic (i.e., microbe-free) mice, zebrafish, and fruit flies exhibit increased locomotor behavior, or hyperactivity. The mechanism through which bacteria interact with host cells to trigger normal neurobehavioral development in larval zebrafish is not well understood. Here, we monoassociated zebrafish with either one of six different zebrafish-associated bacteria, mixtures of these host-associates, or with an environmental bacterial isolate. Results As predicted, the axenic cohort was hyperactive. Monoassociation with three different host-associated bacterial species, as well as with the mixtures, resulted in control-like locomotor behavior. Monoassociation with one host-associate and the environmental isolate resulted in the hyperactive phenotype characteristic of axenic larvae, while monoassociation with two other host-associated bacteria partially blocked this phenotype. Furthermore, we found an inverse relationship between the total concentration of bacteria per larvae and locomotor behavior. Lastly, in the axenic and associated cohorts, but not in the larvae with complex communities, we detected unexpected bacteria, some of which may be present as facultative predators. Conclusions These data support a growing body of evidence that individual species of bacteria can have different effects on host behavior, potentially related to their success at intestinal colonization. Specific to the zebrafish model, our results suggest that differences in the composition of microbes in fish facilities could affect the results of behavioral assays within pharmacological and toxicological studies.

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