Effects of Manganese on Genomic Integrity in the Multicellular Model Organism Caenorhabditis elegans

Although manganese (Mn) is an essential trace element, overexposure is associated with Mn-induced toxicity and neurological dysfunction. Even though Mn-induced oxidative stress is discussed extensively, neither the underlying mechanisms of the potential consequences of Mn-induced oxidative stress on DNA damage and DNA repair, nor the possibly resulting toxicity are characterized yet. In this study, we use the model organism Caenorhabditis elegans to investigate the mode of action of Mn toxicity, focusing on genomic integrity by means of DNA damage and DNA damage response. Experiments were conducted to analyze Mn bioavailability, lethality, and induction of DNA damage. Different deletion mutant strains were then used to investigate the role of base excision repair (BER) and dePARylation (DNA damage response) proteins in Mn-induced toxicity. The results indicate a dose- and time-dependent uptake of Mn, resulting in increased lethality. Excessive exposure to Mn decreases genomic integrity and activates BER. Altogether, this study characterizes the consequences of Mn exposure on genomic integrity and therefore broadens the molecular understanding of pathways underlying Mn-induced toxicity. Additionally, studying the basal poly(ADP-ribosylation) (PARylation) of worms lacking poly(ADP-ribose) glycohydrolase (PARG) parg-1 or parg-2 (two orthologue of PARG), indicates that parg-1 accounts for most of the glycohydrolase activity in worms.

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Sites of Acetylation on Newly Synthesized Histone H4 Are Required for Chromatin Assembly and DNA Damage Response Signaling

Molecular and Cellular Biology ◽

10.1128/mcb.00460-13 ◽

2013 ◽

Vol 33 (16) ◽

pp. 3286-3298 ◽

Cited By ~ 19

Author(s):

Zhongqi Ge ◽

Devi Nair ◽

Xiaoyan Guan ◽

Neha Rastogi ◽

Michael A. Freitas ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Histone H3 ◽

Model Organism ◽

Strand Break ◽

Chromatin Assembly ◽

Histone H4 ◽

Histone H4 Acetylation ◽

Damage Response ◽

A Site

The best-characterized acetylation of newly synthesized histone H4 is the diacetylation of the NH2-terminal tail on lysines 5 and 12. Despite its evolutionary conservation, this pattern of modification has not been shown to be essential for either viability or chromatin assembly in any model organism. We demonstrate that mutations in histone H4 lysines 5 and 12 in yeast confer hypersensitivity to replication stress and DNA-damaging agents when combined with mutations in histone H4 lysine 91, which has also been found to be a site of acetylation on soluble histone H4. In addition, these mutations confer a dramatic decrease in cell viability when combined with mutations in histone H3 lysine 56. We also show that mutation of the sites of acetylation on newly synthesized histone H4 results in defects in the reassembly of chromatin structure that accompanies the repair of HO-mediated double-strand breaks. This defect is not due to a decrease in the level of histone H3 lysine 56 acetylation. Intriguingly, mutations that alter the sites of newly synthesized histone H4 acetylation display a marked decrease in levels of phosphorylated H2A (γ-H2AX) in chromatin surrounding the double-strand break. These results indicate that the sites of acetylation on newly synthesized histones H3 and H4 can function in nonoverlapping ways that are required for chromatin assembly, viability, and DNA damage response signaling.

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Corrigendum to “DNA damage response protein ASCIZ links base excision repair with immunoglobulin gene conversion” [Biochem. Biophys. Res. Commun. 371 (2008) 225–229]

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2008.09.104 ◽

2008 ◽

Vol 377 (1) ◽

pp. 326

Author(s):

Hayato Oka ◽

Wataru Sakai ◽

Eiichiro Sonoda ◽

Jun Nakamura ◽

Kenjiro Asagoshi ◽

...

Keyword(s):

Dna Damage ◽

Gene Conversion ◽

Dna Damage Response ◽

Base Excision Repair ◽

Excision Repair ◽

Immunoglobulin Gene ◽

Damage Response ◽

Base Excision

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DNA Damage Response and Oxidative Stress in Systemic Autoimmunity

International Journal of Molecular Sciences ◽

10.3390/ijms21010055 ◽

2019 ◽

Vol 21 (1) ◽

pp. 55 ◽

Cited By ~ 8

Author(s):

Vassilis L. Souliotis ◽

Nikolaos I. Vlachogiannis ◽

Maria Pappa ◽

Alexandra Argyriou ◽

Panagiotis A. Ntouros ◽

...

Keyword(s):

Oxidative Stress ◽

Immune Response ◽

Dna Damage ◽

Autoimmune Diseases ◽

Dna Damage Response ◽

Lupus Erythematosus ◽

Mononuclear Cells ◽

Tissue Injury ◽

Systemic Autoimmune Diseases ◽

Damage Response

The DNA damage response and repair (DDR/R) network, a sum of hierarchically structured signaling pathways that recognize and repair DNA damage, and the immune response to endogenous and/or exogenous threats, act synergistically to enhance cellular defense. On the other hand, a deregulated interplay between these systems underlines inflammatory diseases including malignancies and chronic systemic autoimmune diseases, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. Patients with these diseases are characterized by aberrant immune response to self-antigens with widespread production of autoantibodies and multiple-tissue injury, as well as by the presence of increased oxidative stress. Recent data demonstrate accumulation of endogenous DNA damage in peripheral blood mononuclear cells from these patients, which is related to (a) augmented DNA damage formation, at least partly due to the induction of oxidative stress, and (b) epigenetically regulated functional abnormalities of fundamental DNA repair mechanisms. Because endogenous DNA damage accumulation has serious consequences for cellular health, including genomic instability and enhancement of an aberrant immune response, these results can be exploited for understanding pathogenesis and progression of systemic autoimmune diseases, as well as for the development of new treatments.

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Nucleotide Excision Repair Protein Rad23 Regulates Cell Virulence Independent of Rad4 in Candida albicans

mSphere ◽

10.1128/msphere.00062-20 ◽

2020 ◽

Vol 5 (1) ◽

Cited By ~ 1

Author(s):

Jia Feng ◽

Shuangyan Yao ◽

Yansong Dong ◽

Jing Hu ◽

Malcolm Whiteway ◽

...

Keyword(s):

Dna Damage ◽

Candida Albicans ◽

Nucleotide Excision Repair ◽

Dna Damage Response ◽

Excision Repair ◽

Content Type ◽

Virulence Regulation ◽

Nucleotide Excision ◽

Damage Response

ABSTRACT In the pathogenic yeast Candida albicans, the DNA damage response contributes to pathogenicity by regulating cell morphology transitions and maintaining survival in response to DNA damage induced by reactive oxygen species (ROS) in host cells. However, the function of nucleotide excision repair (NER) in C. albicans has not been extensively investigated. To better understand the DNA damage response and its role in virulence, we studied the function of the Rad23 nucleotide excision repair protein in detail. The RAD23 deletion strain and overexpression strain both exhibit UV sensitivity, confirming the critical role of RAD23 in the nucleotide excision repair pathway. Genetic interaction assays revealed that the role of RAD23 in the UV response relies on RAD4 but is independent of RAD53, MMS22, and RAD18. RAD4 and RAD23 have similar roles in regulating cell morphogenesis and biofilm formation; however, only RAD23, but not RAD4, plays a negative role in virulence regulation in a mouse model. We found that the RAD23 deletion strain showed decreased survival in a Candida-macrophage interaction assay. Transcriptome sequencing (RNA-seq) and quantitative real-time PCR (qRT-PCR) data further revealed that RAD23, but not RAD4, regulates the transcription of a virulence factor, SUN41, suggesting a unique role of RAD23 in virulence regulation. Taking these observations together, our work reveals that the RAD23-related nucleotide excision pathway plays a critical role in the UV response but may not play a direct role in virulence. The virulence-related role of RAD23 may rely on the regulation of several virulence factors, which may give us further understanding about the linkage between DNA damage repair and virulence regulation in C. albicans. IMPORTANCE Candida albicans remains a significant threat to the lives of immunocompromised people. An understanding of the virulence and infection ability of C. albicans cells in the mammalian host may help with clinical treatment and drug discovery. The DNA damage response pathway is closely related to morphology regulation and virulence, as well as the ability to survive in host cells. In this study, we checked the role of the nucleotide excision repair (NER) pathway, the key repair system that functions to remove a large variety of DNA lesions such as those caused by UV light, but whose function has not been well studied in C. albicans. We found that Rad23, but not Rad4, plays a role in virulence that appears independent of the function of the NER pathway. Our research revealed that the NER pathway represented by Rad4/Rad23 may not play a direct role in virulence but that Rad23 may play a unique role in regulating the transcription of virulence genes that may contribute to the virulence of C. albicans.

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APE2 Is a General Regulator of the ATR-Chk1 DNA Damage Response Pathway to Maintain Genome Integrity in Pancreatic Cancer Cells

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.738502 ◽

2021 ◽

Vol 9 ◽

Author(s):

Md Akram Hossain ◽

Yunfeng Lin ◽

Garrett Driscoll ◽

Jia Li ◽

Anne McMahon ◽

...

Keyword(s):

Oxidative Stress ◽

Pancreatic Cancer ◽

Dna Damage ◽

Cancer Cells ◽

Dna Damage Response ◽

Human Pancreatic Cancer ◽

Genome Integrity ◽

Pancreatic Cancer Cells ◽

Damage Response ◽

Egg Extracts

The maintenance of genome integrity and fidelity is vital for the proper function and survival of all organisms. Recent studies have revealed that APE2 is required to activate an ATR-Chk1 DNA damage response (DDR) pathway in response to oxidative stress and a defined DNA single-strand break (SSB) in Xenopus laevis egg extracts. However, it remains unclear whether APE2 is a general regulator of the DDR pathway in mammalian cells. Here, we provide evidence using human pancreatic cancer cells that APE2 is essential for ATR DDR pathway activation in response to different stressful conditions including oxidative stress, DNA replication stress, and DNA double-strand breaks. Fluorescence microscopy analysis shows that APE2-knockdown (KD) leads to enhanced γH2AX foci and increased micronuclei formation. In addition, we identified a small molecule compound Celastrol as an APE2 inhibitor that specifically compromises the binding of APE2 but not RPA to ssDNA and 3′-5′ exonuclease activity of APE2 but not APE1. The impairment of ATR-Chk1 DDR pathway by Celastrol in Xenopus egg extracts and human pancreatic cancer cells highlights the physiological significance of Celastrol in the regulation of APE2 functionalities in genome integrity. Notably, cell viability assays demonstrate that APE2-KD or Celastrol sensitizes pancreatic cancer cells to chemotherapy drugs. Overall, we propose APE2 as a general regulator for the DDR pathway in genome integrity maintenance.

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RTT109 AND Fun30 proteins mediate epigenetic regulation of the DNA damage response pathway in C. albicans

10.1101/2021.07.22.453354 ◽

2021 ◽

Author(s):

Prashant Kumar Maurya ◽

Pramita Garai ◽

Kaveri Goel ◽

Himanshu Bhatt ◽

Aarti Goyal ◽

...

Keyword(s):

Oxidative Stress ◽

Dna Damage ◽

Dna Damage Response ◽

Regulation Of Gene Expression ◽

Repair Pathway ◽

Fungal Cell ◽

Opportunistic Fungi ◽

Damage Response ◽

H3 Acetylation ◽

Dna Damage Response Pathway

Fun30, an ATP-dependent chromatin remodeller, from S. cerevisiae mediates both regulation of gene expression as well as DNA damage response/repair. In this paper, we have characterized the biochemical and physiological function of Fun30 from the opportunistic fungi, C. albicans. Biochemically, the protein shows DNA-stimulated ATPase activity. Physiologically, the protein co-regulates transcription of RTT109, TEL1, MEC1, and SNF2-genes that encode for proteins involved in DNA damage response and repair pathway. The expression of FUN30, in turn, is regulated by histone H3 acetylation catalysed by Rtt109 encoded by RTT109. The RTT109Hz/FUN30Hz mutant strain shows sensitivity to oxidative stress and resistance to MMS as compared to the wild type strain. Quantitative PCR showed that the sensitivity to oxidative stress results from downregulation of MEC1, RAD9, MRC1 and RAD5 expression; ChIP experiments showed Fun30 but not H3ac regulates the expression of these genes in response to oxidative stress. In contrast, on treatment with MMS, the expression of RAD9 is upregulated and this upregulation is co-regulated by both Fun30 and H3 acetylation catalysed by Rtt109. Thus, Fun30 and H3 acetylation mediate the response of the fungal cell to genotoxic agents in C. albicans by regulating the expression of DNA damage response and repair pathway genes.

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Ataxia Telangiectasia Mutated Kinase Mediates NF-κB Serine 276 Phosphorylation and Interferon Expression via the IRF7-RIG-I Amplification Loop in Paramyxovirus Infection

Journal of Virology ◽

10.1128/jvi.02458-14 ◽

2014 ◽

Vol 89 (5) ◽

pp. 2628-2642 ◽

Cited By ~ 18

Author(s):

Ling Fang ◽

Sanjeev Choudhary ◽

Bing Tian ◽

Istvan Boldogh ◽

Chunying Yang ◽

...

Keyword(s):

Oxidative Stress ◽

Dna Damage ◽

Retinoic Acid ◽

Dna Damage Response ◽

Type I ◽

Regulatory Factor ◽

Ataxia Telangiectasia Mutated ◽

Damage Response ◽

Amplification Loop ◽

Inducible Gene

ABSTRACTRespiratory syncytial virus (RSV) is a primary etiological agent of childhood lower respiratory tract disease. Molecular patterns induced by active infection trigger a coordinated retinoic acid-inducible gene I (RIG-I)-Toll-like receptor (TLR) signaling response to induce inflammatory cytokines and antiviral mucosal interferons. Recently, we discovered a nuclear oxidative stress-sensitive pathway mediated by the DNA damage response protein, ataxia telangiectasia mutated (ATM), in cytokine-induced NF-κB/RelA Ser 276 phosphorylation. Here we observe that ATM silencing results in enhanced single-strand RNA (ssRNA) replication of RSVand Sendai virus, due to decreased expression and secretion of type I and III interferons (IFNs), despite maintenance of IFN regulatory factor 3 (IRF3)-dependent IFN-stimulated genes (ISGs). In addition to enhanced oxidative stress, RSV replication enhances foci of phosphorylated histone 2AX variant (γH2AX), Ser 1981 phosphorylation of ATM, and IKKγ/NEMO-dependent ATM nuclear export, indicating activation of the DNA damage response. ATM-deficient cells show defective RSV-induced mitogen and stress-activated kinase 1 (MSK-1) Ser 376 phosphorylation and reduced RelA Ser 276 phosphorylation, whose formation is required for IRF7 expression. We observe that RelA inducibly binds the native IFN regulatory factor 7 (IRF7) promoter in an ATM-dependent manner, and IRF7 inducibly binds to the endogenous retinoic acid-inducible gene I (RIG-I) promoter. Ectopic IRF7 expression restores RIG-I expression and type I/III IFN expression in ATM-silenced cells. We conclude that paramyxoviruses trigger the DNA damage response, a pathway required for MSK1 activation of phospho Ser 276 RelA formation to trigger the IRF7-RIG-I amplification loop necessary for mucosal IFN production. These data provide the molecular pathogenesis for defects in the cellular innate immunity of patients with homozygous ATM mutations.IMPORTANCERNA virus infections trigger cellular response pathways to limit spread to adjacent tissues. This “innate immune response” is mediated by germ line-encoded pattern recognition receptors that trigger activation of two, largely independent, intracellular NF-κB and IRF3 transcription factors. Downstream, expression of protective antiviral interferons is amplified by positive-feedback loops mediated by inducible interferon regulatory factors (IRFs) and retinoic acid inducible gene (RIG-I). Our results indicate that a nuclear oxidative stress- and DNA damage-sensing factor, ATM, is required to mediate a cross talk pathway between NF-κB and IRF7 through mediating phosphorylation of NF-κB. Our studies provide further information about the defects in cellular and innate immunity in patients with inherited ATM mutations.

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Role of histone deacetylase 2 in epigenetics and cellular senescence: implications in lung inflammaging and COPD

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00175.2012 ◽

2012 ◽

Vol 303 (7) ◽

pp. L557-L566 ◽

Cited By ~ 70

Author(s):

Hongwei Yao ◽

Irfan Rahman

Keyword(s):

Oxidative Stress ◽

Dna Damage ◽

Histone Deacetylase ◽

Dna Damage Response ◽

Cellular Senescence ◽

Premature Aging ◽

Epigenetic Mechanism ◽

Histone Deacetylase 2 ◽

Damage Response

Histone deacetylase 2 (HDAC2) is a class I histone deacetylase that regulates various cellular processes, such as cell cycle, senescence, proliferation, differentiation, development, apoptosis, and glucocorticoid function in inhibiting inflammatory response. HDAC2 has been shown to protect against DNA damage response and cellular senescence/premature aging via an epigenetic mechanism in response to oxidative stress. These phenomena are observed in patients with chronic obstructive pulmonary disease (COPD). HDAC2 is posttranslationally modified by oxidative/carbonyl stress imposed by cigarette smoke and oxidants, leading to its reduction via an ubiquitination-proteasome dependent degradation in lungs of patients with COPD. In this perspective, we have discussed the role of HDAC2 posttranslational modifications and its role in regulation of inflammation, histone/DNA epigenetic modifications, DNA damage response, and cellular senescence, particularly in inflammaging, and during the development of COPD. We have also discussed the potential directions for future translational research avenues in modulating lung inflammaging and cellular senescence based on epigenetic chromatin modifications in diseases associated with increased oxidative stress.

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