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Interactive Roles of DNA Helicases and Translocases with the Single-Stranded DNA Binding Protein RPA in Nucleic Acid Metabolism. Int J Mol Sci 2017; 18:ijms18061233. [PMID: 28594346 PMCID: PMC5486056 DOI: 10.3390/ijms18061233] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/30/2017] [Accepted: 06/01/2017] [Indexed: 01/05/2023] Open
Abstract
Helicases and translocases use the energy of nucleoside triphosphate binding and hydrolysis to unwind/resolve structured nucleic acids or move along a single-stranded or double-stranded polynucleotide chain, respectively. These molecular motors facilitate a variety of transactions including replication, DNA repair, recombination, and transcription. A key partner of eukaryotic DNA helicases/translocases is the single-stranded DNA binding protein Replication Protein A (RPA). Biochemical, genetic, and cell biological assays have demonstrated that RPA interacts with these human molecular motors physically and functionally, and their association is enriched in cells undergoing replication stress. The roles of DNA helicases/translocases are orchestrated with RPA in pathways of nucleic acid metabolism. RPA stimulates helicase-catalyzed DNA unwinding, enlists translocases to sites of action, and modulates their activities in DNA repair, fork remodeling, checkpoint activation, and telomere maintenance. The dynamic interplay between DNA helicases/translocases and RPA is just beginning to be understood at the molecular and cellular levels, and there is still much to be learned, which may inform potential therapeutic strategies.
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52
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Crouch JD, Brosh RM. Mechanistic and biological considerations of oxidatively damaged DNA for helicase-dependent pathways of nucleic acid metabolism. Free Radic Biol Med 2017; 107:245-257. [PMID: 27884703 PMCID: PMC5440220 DOI: 10.1016/j.freeradbiomed.2016.11.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/11/2016] [Accepted: 11/13/2016] [Indexed: 12/21/2022]
Abstract
Cells are under constant assault from reactive oxygen species that occur endogenously or arise from environmental agents. An important consequence of such stress is the generation of oxidatively damaged DNA, which is represented by a wide range of non-helix distorting and helix-distorting bulkier lesions that potentially affect a number of pathways including replication and transcription; consequently DNA damage tolerance and repair pathways are elicited to help cells cope with the lesions. The cellular consequences and metabolism of oxidatively damaged DNA can be quite complex with a number of DNA metabolic proteins and pathways involved. Many of the responses to oxidative stress involve a specialized class of enzymes known as helicases, the topic of this review. Helicases are molecular motors that convert the energy of nucleoside triphosphate hydrolysis to unwinding of structured polynucleic acids. Helicases by their very nature play fundamentally important roles in DNA metabolism and are implicated in processes that suppress chromosomal instability, genetic disease, cancer, and aging. We will discuss the roles of helicases in response to nuclear and mitochondrial oxidative stress and how this important class of enzymes help cells cope with oxidatively generated DNA damage through their functions in the replication stress response, DNA repair, and transcriptional regulation.
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Affiliation(s)
- Jack D Crouch
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, NIH Biomedical Research Center, 251 Bayview Blvd, Baltimore, MD 21224, USA
| | - Robert M Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, NIH Biomedical Research Center, 251 Bayview Blvd, Baltimore, MD 21224, USA.
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53
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Coluzzi E, Buonsante R, Leone S, Asmar AJ, Miller KL, Cimini D, Sgura A. Transient ALT activation protects human primary cells from chromosome instability induced by low chronic oxidative stress. Sci Rep 2017; 7:43309. [PMID: 28240303 PMCID: PMC5327399 DOI: 10.1038/srep43309] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 01/25/2017] [Indexed: 12/22/2022] Open
Abstract
Cells are often subjected to the effect of reactive oxygen species (ROS) as a result of both intracellular metabolism and exposure to exogenous factors. ROS-dependent oxidative stress can induce 8-oxodG within the GGG triplet found in the G-rich human telomeric sequence (TTAGGG), making telomeres highly susceptible to ROS-induced oxidative damage. Telomeres are nucleoprotein complexes that protect the ends of linear chromosomes and their dysfunction is believed to affect a wide range of cellular and/or organismal processes. Acute oxidative stress was shown to affect telomere integrity, but how prolonged low level oxidative stress, which may be more physiologically relevant, affects telomeres is still poorly investigated. Here, we explored this issue by chronically exposing human primary fibroblasts to a low dose of hydrogen peroxide. We observed fluctuating changes in telomere length and fluctuations in the rates of chromosome instability phenotypes, such that when telomeres shortened, chromosome instability increased and when telomeres lengthened, chromosome instability decreased. We found that telomere length fluctuation is associated with transient activation of an alternative lengthening of telomere (ALT) pathway, but found no evidence of cell death, impaired proliferation, or cell cycle arrest, suggesting that ALT activation may prevent oxidative damage from reaching levels that threaten cell survival.
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Affiliation(s)
- Elisa Coluzzi
- Department of Science, University Roma Tre, V. le G. Marconi, 446, 00146, Rome, Italy
| | - Rossella Buonsante
- Department of Science, University Roma Tre, V. le G. Marconi, 446, 00146, Rome, Italy
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Stefano Leone
- Department of Science, University Roma Tre, V. le G. Marconi, 446, 00146, Rome, Italy
| | - Anthony J. Asmar
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Kelley L. Miller
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Daniela Cimini
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
- Biocomplexity Institute, Virginia Tech, 1015 Life Science Circle, Blacksburg, VA, 24061, USA
| | - Antonella Sgura
- Department of Science, University Roma Tre, V. le G. Marconi, 446, 00146, Rome, Italy
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54
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Telomeres are elongated in older individuals in a hibernating rodent, the edible dormouse (Glis glis). Sci Rep 2016; 6:36856. [PMID: 27883035 PMCID: PMC5121655 DOI: 10.1038/srep36856] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 10/14/2016] [Indexed: 12/11/2022] Open
Abstract
Telomere shortening is thought to be an important biomarker for life history traits such as lifespan and aging, and can be indicative of genome integrity, survival probability and the risk of cancer development. In humans and other animals, telomeres almost always shorten with age, with more rapid telomere attrition in short-lived species. Here, we show that in the edible dormouse (Glis glis) telomere length significantly increases from an age of 6 to an age of 9 years. While this finding could be due to higher survival of individuals with longer telomeres, we also found, using longitudinal measurements, a positive effect of age on the rate of telomere elongation within older individuals. To our knowledge, no previous study has reported such an effect of age on telomere lengthening. We attribute this exceptional pattern to the peculiar life-history of this species, which skips reproduction in years with low food availability. Further, we show that this “sit tight” strategy in the timing of reproduction is associated with an increasing likelihood for an individual to reproduce as it ages. As reproduction could facilitate telomere attrition, this life-history strategy may have led to the evolution of increased somatic maintenance and telomere elongation with increasing age.
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55
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Fouquerel E, Lormand J, Bose A, Lee HT, Kim GS, Li J, Sobol RW, Freudenthal BD, Myong S, Opresko PL. Oxidative guanine base damage regulates human telomerase activity. Nat Struct Mol Biol 2016; 23:1092-1100. [PMID: 27820808 PMCID: PMC5140714 DOI: 10.1038/nsmb.3319] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 10/11/2016] [Indexed: 12/19/2022]
Abstract
Changes in telomere length are associated with degenerative diseases and cancer. Oxidative stress and DNA damage have been linked to both positive and negative alterations in telomere length and integrity. Here we examined how the common oxidative lesion 8-oxo-7,8-dihydro-2′-deoxyguanine (8-oxoG) regulates telomere elongation by telomerase. When present in the deoxynucleoside triphosphate pool as 8-oxodGTP, telomerase utilization of the oxidized nucleotide during telomere extension is mutagenic and terminates further elongation. Depletion of the enzyme that removes oxidized dNTPs, MTH1, increases telomere dysfunction and cell death in telomerase positive cancer cells harboring shortened telomeres. In contrast, a pre-existing 8-oxoG within the telomeric DNA sequence promotes telomerase activity by destabilizing G-quadruplex structure in the DNA. We show that the mechanism by which 8-oxoG arises in the telomere, either by insertion of oxidized nucleotides or by direct reaction with free radicals, dictates whether telomerase is inhibited or stimulated and thereby, mediates the biological outcome.
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Affiliation(s)
- Elise Fouquerel
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, and University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
| | - Justin Lormand
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, and University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
| | - Arindam Bose
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, and University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
| | - Hui-Ting Lee
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Grace S Kim
- Department of Bioengineering, University of Illinois, Urbana, IL, USA
| | - Jianfeng Li
- University of South Alabama Mitchell Cancer Institute, Mobile, AL, USA
| | - Robert W Sobol
- University of South Alabama Mitchell Cancer Institute, Mobile, AL, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Sua Myong
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA.,Department of Bioengineering, University of Illinois, Urbana, IL, USA
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, and University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA.,Center for Nucleic Acids Science and Technology, Carnegie Mellon University, Pittsburgh, PA, USA
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56
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Workalemahu T, Enquobahrie DA, Yohannes E, Sanchez SE, Gelaye B, Qiu C, Williams MA. Placental telomere length and risk of placental abruption. J Matern Fetal Neonatal Med 2016; 29:2767-72. [PMID: 26611732 PMCID: PMC4984533 DOI: 10.3109/14767058.2015.1103224] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To investigate the associations of placental telomere length with placental abruption (PA) risk and interactions between placental telomere length and placental mitochondrial DNA (mtDNA) copy number on PA risk. MATERIALS AND METHODS Relative telomere length and mtDNA copy number in placental samples collected from 105 cases and 73 controls were measured in two batches using qRT-PCR. Mean differences in relative telomere length between PA cases and controls were examined. After creating batch-specific median cutoffs for relative telomere length (84.92 and 102.53) and mtDNA copy number (2.32 and 1.42), interaction between the two variables was examined using stratified logistic regression models. RESULTS Adjusted mean difference in relative telomere length between PA cases and controls was -0.07 (p > 0.05). Among participants with low mtDNA copy number, participants with short relative telomere length had a 3.07-fold higher odds (95% CI: 1.13-8.38) of PA as compared with participants with long relative telomere length (the reference group). Among participants with high mtDNA copy number, participants with short relative telomere length had a 0.71-fold lower odds (95% CI: 0.28-1.83) of PA as compared with the reference group (interaction p values = 0.03). CONCLUSION Findings suggest complex relationships between placental telomere length, mtDNA copy number and PA risk which warrant further larger studies.
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Affiliation(s)
| | - Daniel A. Enquobahrie
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington
- Center for Perinatal Studies, Swedish Medical Center, Seattle, Washington
| | - Ermias Yohannes
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington
| | | | - Bizu Gelaye
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Chunfang Qiu
- Center for Perinatal Studies, Swedish Medical Center, Seattle, Washington
| | - Michelle A. Williams
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
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Abstract
Telomeres at chromosome ends are nucleoprotein structures consisting of tandem TTAGGG repeats and a complex of proteins termed shelterin. DNA damage and repair at telomeres is uniquely influenced by the ability of telomeric DNA to form alternate structures including loops and G-quadruplexes, coupled with the ability of shelterin proteins to interact with and regulate enzymes in every known DNA repair pathway. The role of shelterin proteins in preventing telomeric ends from being falsely recognized and processed as DNA double strand breaks is well established. Here we focus instead on recent developments in understanding the roles of shelterin proteins and telomeric DNA sequence and structure in processing genuine damage at telomeres induced by endogenous and exogenous DNA damage agents. We will highlight advances in double strand break repair, base excision repair and nucleotide excision repair at telomeres, and will discuss important questions remaining in the field.
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Affiliation(s)
- Elise Fouquerel
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh Cancer Institute Research Pavilion, 5117 Centre Avenue, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Dhvani Parikh
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh Cancer Institute Research Pavilion, 5117 Centre Avenue, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Patricia Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh Cancer Institute Research Pavilion, 5117 Centre Avenue, University of Pittsburgh, Pittsburgh, PA 15213, United States.
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58
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Byrd AK, Zybailov BL, Maddukuri L, Gao J, Marecki JC, Jaiswal M, Bell MR, Griffin WC, Reed MR, Chib S, Mackintosh SG, MacNicol AM, Baldini G, Eoff RL, Raney KD. Evidence That G-quadruplex DNA Accumulates in the Cytoplasm and Participates in Stress Granule Assembly in Response to Oxidative Stress. J Biol Chem 2016; 291:18041-57. [PMID: 27369081 DOI: 10.1074/jbc.m116.718478] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Indexed: 12/13/2022] Open
Abstract
Cells engage numerous signaling pathways in response to oxidative stress that together repair macromolecular damage or direct the cell toward apoptosis. As a result of DNA damage, mitochondrial DNA or nuclear DNA has been shown to enter the cytoplasm where it binds to "DNA sensors," which in turn initiate signaling cascades. Here we report data that support a novel signaling pathway in response to oxidative stress mediated by specific guanine-rich sequences that can fold into G-quadruplex DNA (G4DNA). In response to oxidative stress, we demonstrate that sequences capable of forming G4DNA appear at increasing levels in the cytoplasm and participate in assembly of stress granules. Identified proteins that bind to endogenous G4DNA in the cytoplasm are known to modulate mRNA translation and participate in stress granule formation. Consistent with these findings, stress granule formation is known to regulate mRNA translation during oxidative stress. We propose a signaling pathway whereby cells can rapidly respond to DNA damage caused by oxidative stress. Guanine-rich sequences that are excised from damaged genomic DNA are proposed to enter the cytoplasm where they can regulate translation through stress granule formation. This newly proposed role for G4DNA provides an additional molecular explanation for why such sequences are prevalent in the human genome.
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Affiliation(s)
- Alicia K Byrd
- From the Departments of Biochemistry and Molecular Biology and
| | - Boris L Zybailov
- From the Departments of Biochemistry and Molecular Biology and the University of Arkansas at Little Rock/University of Arkansas for Medical Sciences (UALR/UAMS) Joint Graduate Program in Bioinformatics, University of Arkansas at Little Rock, Little Rock, Arkansas 72204
| | - Leena Maddukuri
- From the Departments of Biochemistry and Molecular Biology and
| | - Jun Gao
- From the Departments of Biochemistry and Molecular Biology and
| | - John C Marecki
- From the Departments of Biochemistry and Molecular Biology and
| | - Mihir Jaiswal
- the University of Arkansas at Little Rock/University of Arkansas for Medical Sciences (UALR/UAMS) Joint Graduate Program in Bioinformatics, University of Arkansas at Little Rock, Little Rock, Arkansas 72204
| | - Matthew R Bell
- From the Departments of Biochemistry and Molecular Biology and
| | | | - Megan R Reed
- From the Departments of Biochemistry and Molecular Biology and
| | - Shubeena Chib
- From the Departments of Biochemistry and Molecular Biology and
| | - Samuel G Mackintosh
- From the Departments of Biochemistry and Molecular Biology and the Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and
| | - Angus M MacNicol
- the Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and Neurobiology and Developmental Sciences and
| | - Giulia Baldini
- From the Departments of Biochemistry and Molecular Biology and
| | - Robert L Eoff
- From the Departments of Biochemistry and Molecular Biology and the Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and
| | - Kevin D Raney
- From the Departments of Biochemistry and Molecular Biology and the Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and
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59
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Tan R, Lan L. Guarding chromosomes from oxidative DNA damage to the very end. Acta Biochim Biophys Sin (Shanghai) 2016; 48:617-22. [PMID: 27174872 DOI: 10.1093/abbs/gmw040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 04/05/2016] [Indexed: 11/12/2022] Open
Abstract
The ends of each chromosome are capped by the telomere assembly to protect chromosomal integrity from telomere attrition and DNA damage. In response to DNA damage, DNA repair factors are enriched at damage sites by a sophisticated signaling and recruitment cascade. However, DNA damage response at telomeres is different from non-telomeric region of genomic DNA due to specialized sequences and structures of the telomeres. In the course of normal DNA replication or DNA damage repair, both the telomere shelterin protein complex and the condensed telomeric chromatin structure in mammalian cells are modified to protect telomeres from exposing free DNA ends which are subject to both telemere shortening and chromosome end fusion. Initiation of either homologous recombination or non-homologous end joint repair at telomeres requires disassembling and/or post-translational modifications of the shelterin complex and telomeric chromatin. In addition, cancer cells utilize distinct mechanisms to maintain telomere length and cell survival upon damage. In this review, we summarize current studies that focus on telomere end protection and telomere DNA repair using different methodologies to model telomere DNA damage and disruption. These include genetic ablation of sheltering proteins, targeting endonuclease to telomeres, and delivering oxidative damage directly. These different approaches, when combined, offer better understanding of the mechanistic differences in DNA damage response between telomeric and genomic DNA, which will provide new hope to identify potential cancer therapeutic targets to curtail cancer cell proliferation via induction of telomere dysfunctions.
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Affiliation(s)
- Rong Tan
- Xiangya Hospital, Central South University, Changsha 410008, China University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Li Lan
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
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60
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Mishra S, Kumar R, Malhotra N, Singh N, Dada R. Mild oxidative stress is beneficial for sperm telomere length maintenance. World J Methodol 2016; 6:163-170. [PMID: 27376021 PMCID: PMC4921947 DOI: 10.5662/wjm.v6.i2.163] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 11/24/2015] [Accepted: 03/23/2016] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate telomere length in sperm DNA and its correlation with oxidative stress (normal, mild, severe).
METHODS: The study included infertile men (n = 112) and age matched fertile controls (n = 102). The average telomere length from the sperm DNA was measured using a quantitative real time PCR based assay. Seminal reactive oxygen species (ROS) and 8-Isoprostane (8-IP) levels were measured by chemiluminescence assay and ELISA respectively.
RESULTS: Average sperm telomere length in infertile men and controls was 0.609 ± 0.15 and 0.789 ± 0.060, respectively (P < 0.0001). Seminal ROS levels in infertile was higher [66.61 ± 28.32 relative light units (RLU)/s/million sperm] than in controls (14.04 ± 10.67 RLU/s/million sperm) (P < 0.0001). The 8-IP level in infertile men was significantly higher (421.55 ± 131.29 pg/mL) than in controls (275.94 ± 48.13 pg/mL) (P < 0.001). When correlated to oxidative stress, in normal range of oxidative stress (ROS, 0-21.3 RLU/s/million sperm) the average telomere length in cases was 0.663 ± 0.14, in mild oxidative stress (ROS, 21.3-35 RLU/s/million sperm) it was elevated (0.684 ± 0.12) and in severe oxidative stress (ROS > 35 RLU/s/million sperm) average telomere length was decreased to 0.595 ± 0.15.
CONCLUSION: Mild oxidative stress results in lengthening of telomere length, but severe oxidative stress results in shorter telomeres. Although telomere maintenance is a complex trait, the study shows that mild oxidative stress is beneficial in telomere length maintenance and thus a delicate balance needs to be established to maximize the beneficial effects of free radicals and prevent harmful effects of supra physiological levels. Detailed molecular evaluation of telomere structure, its correlation with oxidative stress would aid in elucidating the cause of accelerated telomere length attrition.
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61
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Virgilio A, Esposito V, Mayol L, Giancola C, Petraccone L, Galeone A. The oxidative damage to the human telomere: effects of 5-hydroxymethyl-2'-deoxyuridine on telomeric G-quadruplex structures. Org Biomol Chem 2016; 13:7421-9. [PMID: 25997822 DOI: 10.1039/c5ob00748h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
As part of the genome, human telomeric regions can be damaged by the chemically reactive molecules responsible for oxidative DNA damage. Considering that G-quadruplex structures have been proven to occur in human telomere regions, several studies have been devoted to investigating the effect of oxidation products on the properties of these structures. However only investigations concerning the presence in G-quadruplexes of the main oxidation products of deoxyguanosine and deoxyadenosine have appeared in the literature. Here, we investigated the effects of 5-hydroxymethyl-2'-deoxyuridine (5-hmdU), one of the main oxidation products of T, on the physical-chemical properties of the G-quadruplex structures formed by two human telomeric sequences. Collected calorimetric, circular dichroism and electrophoretic data suggest that, in contrast to most of the results on other damage, the replacement of a T with a 5-hmdU results in only negligible effects on structural stability. Reported results and other data from literature suggest a possible protecting effect of the loop residues on the other parts of the G-quadruplexes.
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Affiliation(s)
- Antonella Virgilio
- Dipartimento di Farmacia, Università degli Studi di Napoli "Federico II", Via D. Montesano 49, I-80131 Napoli, Italy.
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62
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An N, Fleming AM, Burrows CJ. Human Telomere G-Quadruplexes with Five Repeats Accommodate 8-Oxo-7,8-dihydroguanine by Looping out the DNA Damage. ACS Chem Biol 2016; 11:500-7. [PMID: 26686913 DOI: 10.1021/acschembio.5b00844] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inflammation and oxidative stress generate free radicals that oxidize guanine (G) in DNA to 8-oxo-7,8-dihydroguanine (OG), and this reaction is prominent in the G-rich telomere sequence. In telomeres, OG is not efficiently removed by repair pathways allowing its concentration to build, surprisingly without any immediate negative consequences to stability. Herein, OG was synthesized in five repeats of the human telomere sequence (TTAGGG)n, at the 5'-G of the 5'-most, middle, and 3'-most G tracks, representing hotspots for oxidation. These synthetic oligomers were folded in relevant amounts of K(+)/Na(+) to adopt hybrid G-quadruplex folds. The structural impact of OG was assayed by circular dichroism, thermal melting, (1)H NMR, and single-molecule profiling by the α-hemolysin nanopore. On the basis of these results, OG was well accommodated in the five-repeat sequences by looping out the damaged G track to allow the other four tracks to adopt a hybrid G-quadruplex. These results run counter to previous studies with OG in four-repeat telomere sequences that found OG to be highly destabilizing and causing significant reorientation of the fold. When taking a wider view of the human telomere sequence and considering additional repeats, we found OG to cause minimal impact on the structure. The plasticity of this repeat sequence addresses how OG concentrations can increase in telomeres without immediate telomere instability or attrition.
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Affiliation(s)
- Na An
- Department of Chemistry, University of Utah, 315 South 1400
East, Salt Lake City, Utah 84112-0850, United States
| | - Aaron M. Fleming
- Department of Chemistry, University of Utah, 315 South 1400
East, Salt Lake City, Utah 84112-0850, United States
| | - Cynthia J. Burrows
- Department of Chemistry, University of Utah, 315 South 1400
East, Salt Lake City, Utah 84112-0850, United States
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63
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Short Telomeres in Key Tissues Initiate Local and Systemic Aging in Zebrafish. PLoS Genet 2016; 12:e1005798. [PMID: 26789415 PMCID: PMC4720274 DOI: 10.1371/journal.pgen.1005798] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 12/20/2015] [Indexed: 12/30/2022] Open
Abstract
Telomeres shorten with each cell division and telomere dysfunction is a recognized hallmark of aging. Tissue proliferation is expected to dictate the rate at which telomeres shorten. We set out to test whether proliferative tissues age faster than non-proliferative due to telomere shortening during zebrafish aging. We performed a prospective study linking telomere length to tissue pathology and disease. Contrary to expectations, we show that telomeres shorten to critical lengths only in specific tissues and independently of their proliferation rate. Short telomeres accumulate in the gut but not in other highly proliferative tissues such as the blood and gonads. Notably, the muscle, a low proliferative tissue, accumulates short telomeres and DNA damage at the same rate as the gut. Together, our work shows that telomere shortening and DNA damage in key tissues triggers not only local dysfunction but also anticipates the onset of age-associated diseases in other tissues, including cancer. Why, and how, organisms age and ultimately die is a key question of modern biology. Telomeres are considered molecular timekeepers determining cellular lifespans. Within an organism, tissue proliferation is expected to dictate the rate at which telomeres shorten. Using zebrafish, an organism with human-like telomeres, we set out to test whether, in natural aging, proliferative tissues age faster than non-proliferative in a telomere-dependent manner. We found that telomeres shorten with age to a level where they trigger telomere associated DNA damage and culminate in tissue dysfunction, independently of high or low tissue proliferation rates. Specifically, short telomeres accumulate in the gut, a highly proliferative tissue, and in the muscle, a low proliferative tissue, working as direct predictors of cellular damage prior to onset of intestinal inflammation and myocyte degeneration. Based on our data, we propose a model where telomere shortening in these key tissues is sufficient to trigger damage in others and precedes the onset of organism age-associated diseases, namely cancer. Thus, tissue-specific telomere length is limiting for local and systemic physiological integrity, leading to tissue degeneration and disease in aging.
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64
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Polettini J, Behnia F, Taylor BD, Saade GR, Taylor RN, Menon R. Telomere Fragment Induced Amnion Cell Senescence: A Contributor to Parturition? PLoS One 2015; 10:e0137188. [PMID: 26397719 PMCID: PMC4580414 DOI: 10.1371/journal.pone.0137188] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/13/2015] [Indexed: 01/08/2023] Open
Abstract
Oxidative stress (OS)-induced senescence of the amniochorion has been associated with parturition at term. We investigated whether telomere fragments shed into the amniotic fluid (AF) correlated with labor status and tested if exogenous telomere fragments (T-oligos) could induce human and murine amnion cell senescence. In a cross-sectional clinical study, AF telomere fragment concentrations quantitated by a validated real-time PCR assay were higher in women in labor at term compared to those not in labor. In vitro treatment of primary human amnion epithelial cells with 40 μM T-oligos ([TTAGGG]2) that mimic telomere fragments, activated p38MAPK, produced senescence-associated (SA) β-gal staining and increased interleukin (IL)-6 and IL-8 production compared to cells treated with complementary DNA sequences (Cont-oligos, [AATCCC]2). T-oligos injected into the uteri of pregnant CD1 mice on day 14 of gestation, led to increased p38MAPK, SA-β-gal (SA β-gal) staining in murine amniotic sacs and higher AF IL-8 levels on day 18, compared to saline treated controls. In summary, term labor AF samples had higher telomere fragments than term not in labor AF. In vitro and in situ telomere fragments increased human and murine amnion p38MAPK, senescence and inflammatory cytokines. We propose that telomere fragments released from senescent fetal cells are indicative of fetal cell aging. Based on our data, these telomere fragments cause oxidative stress associated damages to the term amniotic sac and force them to release other DAMPS, which, in turn, provide a sterile immune response that may be one of the many inflammatory signals required to initiate parturition at term.
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Affiliation(s)
- Jossimara Polettini
- Division of Maternal-Fetal Medicine and Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- Department of Pathology, Botucatu Medical School, UNESP–Univ. Estadual Paulista, Botucatu, Sao Paulo, Brazil
| | - Faranak Behnia
- Division of Maternal-Fetal Medicine and Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Brandie D. Taylor
- Department of Epidemiology & Biostatistics, Texas A&M University System Health Science Center, College Station, Texas, United States of America
| | - George R. Saade
- Division of Maternal-Fetal Medicine and Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Robert N. Taylor
- Department of Obstetrics and Gynecology, Wake Forest University, Winston Salem, North Carolina, United States of America
| | - Ramkumar Menon
- Division of Maternal-Fetal Medicine and Perinatal Research, Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- * E-mail:
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65
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Maynard S, Fang EF, Scheibye-Knudsen M, Croteau DL, Bohr VA. DNA Damage, DNA Repair, Aging, and Neurodegeneration. Cold Spring Harb Perspect Med 2015; 5:cshperspect.a025130. [PMID: 26385091 DOI: 10.1101/cshperspect.a025130] [Citation(s) in RCA: 228] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Aging in mammals is accompanied by a progressive atrophy of tissues and organs, and stochastic damage accumulation to the macromolecules DNA, RNA, proteins, and lipids. The sequence of the human genome represents our genetic blueprint, and accumulating evidence suggests that loss of genomic maintenance may causally contribute to aging. Distinct evidence for a role of imperfect DNA repair in aging is that several premature aging syndromes have underlying genetic DNA repair defects. Accumulation of DNA damage may be particularly prevalent in the central nervous system owing to the low DNA repair capacity in postmitotic brain tissue. It is generally believed that the cumulative effects of the deleterious changes that occur in aging, mostly after the reproductive phase, contribute to species-specific rates of aging. In addition to nuclear DNA damage contributions to aging, there is also abundant evidence for a causative link between mitochondrial DNA damage and the major phenotypes associated with aging. Understanding the mechanistic basis for the association of DNA damage and DNA repair with aging and age-related diseases, such as neurodegeneration, would give insight into contravening age-related diseases and promoting a healthy life span.
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Affiliation(s)
- Scott Maynard
- Department of Cellular and Molecular Medicine, Center for Healthy Aging, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Evandro Fei Fang
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
| | - Morten Scheibye-Knudsen
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
| | - Deborah L Croteau
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
| | - Vilhelm A Bohr
- Department of Cellular and Molecular Medicine, Center for Healthy Aging, University of Copenhagen, DK-2200 Copenhagen, Denmark Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
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Abstract
DNA damage is caused by either endogenous cellular metabolic processes such as hydrolysis, oxidation, alkylation, and DNA base mismatches, or exogenous sources including ultraviolet (UV) light, ionizing radiation, and chemical agents. Damaged DNA that is not properly repaired can lead to genomic instability, driving tumorigenesis. To protect genomic stability, mammalian cells have evolved highly conserved DNA repair mechanisms to remove and repair DNA lesions. Telomeres are composed of long tandem TTAGGG repeats located at the ends of chromosomes. Maintenance of functional telomeres is critical for preventing genome instability. The telomeric sequence possesses unique features that predispose telomeres to a variety of DNA damage induced by environmental genotoxins. This review briefly describes the relevance of excision repair pathways in telomere maintenance, with the focus on base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR). By summarizing current knowledge on excision repair of telomere damage and outlining many unanswered questions, it is our hope to stimulate further interest in a better understanding of excision repair processes at telomeres and in how these processes contribute to telomere maintenance.
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Affiliation(s)
- Pingping Jia
- Elson S. Floyd College of Medicine, United States
| | - Chengtao Her
- School of Molecular Biosciences, Washington State University, United States
| | - Weihang Chai
- Elson S. Floyd College of Medicine, United States; School of Molecular Biosciences, Washington State University, United States.
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67
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Glade MJ, Meguid MM. A glance at … telomeres, oxidative stress, antioxidants, and biological aging. Nutrition 2015; 31:1447-51. [PMID: 26429668 DOI: 10.1016/j.nut.2015.05.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 05/23/2015] [Indexed: 12/14/2022]
Affiliation(s)
| | - Michael M Meguid
- Department of Surgery, University Hospital, Upstate Medical University, Syracuse, New York, USA
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Hwang BJ, Jin J, Gao Y, Shi G, Madabushi A, Yan A, Guan X, Zalzman M, Nakajima S, Lan L, Lu AL. SIRT6 protein deacetylase interacts with MYH DNA glycosylase, APE1 endonuclease, and Rad9-Rad1-Hus1 checkpoint clamp. BMC Mol Biol 2015; 16:12. [PMID: 26063178 PMCID: PMC4464616 DOI: 10.1186/s12867-015-0041-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 05/29/2015] [Indexed: 02/07/2023] Open
Abstract
Background SIRT6, a member of the NAD+-dependent histone/protein deacetylase family, regulates genomic stability, metabolism, and lifespan. MYH glycosylase and APE1 are two base excision repair (BER) enzymes involved in mutation avoidance from oxidative DNA damage. Rad9–Rad1–Hus1 (9–1–1) checkpoint clamp promotes cell cycle checkpoint signaling and DNA repair. BER is coordinated with the checkpoint machinery and requires chromatin remodeling for efficient repair. SIRT6 is involved in DNA double-strand break repair and has been implicated in BER. Here we investigate the direct physical and functional interactions between SIRT6 and BER enzymes. Results We show that SIRT6 interacts with and stimulates MYH glycosylase and APE1. In addition, SIRT6 interacts with the 9-1-1 checkpoint clamp. These interactions are enhanced following oxidative stress. The interdomain connector of MYH is important for interactions with SIRT6, APE1, and 9–1–1. Mutagenesis studies indicate that SIRT6, APE1, and Hus1 bind overlapping but different sequence motifs on MYH. However, there is no competition of APE1, Hus1, or SIRT6 binding to MYH. Rather, one MYH partner enhances the association of the other two partners to MYH. Moreover, APE1 and Hus1 act together to stabilize the MYH/SIRT6 complex. Within human cells, MYH and SIRT6 are efficiently recruited to confined oxidative DNA damage sites within transcriptionally active chromatin, but not within repressive chromatin. In addition, Myh foci induced by oxidative stress and Sirt6 depletion are frequently localized on mouse telomeres. Conclusions Although SIRT6, APE1, and 9-1-1 bind to the interdomain connector of MYH, they do not compete for MYH association. Our findings indicate that SIRT6 forms a complex with MYH, APE1, and 9-1-1 to maintain genomic and telomeric integrity in mammalian cells. Electronic supplementary material The online version of this article (doi:10.1186/s12867-015-0041-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bor-Jang Hwang
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD, 21201, USA.
| | - Jin Jin
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD, 21201, USA.
| | - Ying Gao
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, 5117 Centre Avenue, Pittsburgh, PA, 15213, USA. .,School of Medicine, Tsinghua University, No.1 Tsinghua Yuan, Haidian District, Beijing, 100084, China.
| | - Guoli Shi
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD, 21201, USA. .,University of Maryland School of Nursing, 655 West Lombard Street, Baltimore, MD, 21201, USA.
| | - Amrita Madabushi
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD, 21201, USA. .,Department of Natural and Physical Sciences, Life Sciences Institute, Baltimore City Community College, 801 West Baltimore Street, Baltimore, MD, 21201, USA.
| | - Austin Yan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD, 21201, USA.
| | - Xin Guan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD, 21201, USA.
| | - Michal Zalzman
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD, 21201, USA. .,Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, 16 South Eutaw Street, Baltimore, MD, 21201, USA.
| | - Satoshi Nakajima
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, 5117 Centre Avenue, Pittsburgh, PA, 15213, USA. .,Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, PA, 15219, USA.
| | - Li Lan
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, 5117 Centre Avenue, Pittsburgh, PA, 15213, USA. .,Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, PA, 15219, USA.
| | - A-Lien Lu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD, 21201, USA. .,Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD, 21201, USA.
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Taniguchi Y, Kikukawa Y, Sasaki S. Discrimination Between 8-Oxo-2′-Deoxyguanosine and 2′-Deoxyguanosine in DNA by the Single Nucleotide Primer Extension Reaction with Adap Triphosphate. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201412086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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An N, Fleming AM, White HS, Burrows CJ. Nanopore detection of 8-oxoguanine in the human telomere repeat sequence. ACS NANO 2015; 9:4296-307. [PMID: 25768204 PMCID: PMC4790916 DOI: 10.1021/acsnano.5b00722] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 03/13/2015] [Indexed: 05/23/2023]
Abstract
The human telomere repeat sequence 5'-TTAGGG-3' is a hot spot for oxidation at guanine, yielding 8-oxo-7,8-dihydroguanine (OG), a biomarker of oxidative stress. Telomere shortening resulting from oxidation will ultimately induce cellular senescence. In this study, α-hemolysin (α-HL) nanopore technology was applied to detect and quantify OG in the human telomeric DNA sequence. This repeat sequence adopts a basket G-quadruplex in the NaCl electrolyte used for analysis that enters the α-HL channel, slowly unfolds, and translocates. The basket fold containing OG disrupts the structure, leading to >10× increase in the unfolding kinetics without yielding a detectable current pattern. Therefore, detection of OG with α-HL required labeling of OG with aminomethyl-[18-crown-6] using a mild oxidant. The labeled OG yielded a pulse-like signal in the current vs time trace when the DNA strand was electrophoretically passed through α-HL in NaCl electrolyte. However, the rate of translocation was too slow using NaCl salts, leading us to further refine the method. A mixture of NH4Cl and LiCl electrolytes induced the propeller fold that unravels quickly outside the α-HL channel. This electrolyte allowed observation of the labeled OG, while providing a faster recording of the currents. Lastly, OG distributions were probed with this method in a 120-mer stretch of the human telomere sequence exposed to the cellular oxidant (1)O2. Single-molecule profiles determined the OG distributions to be random in this context. Application of the method in nanomedicine can potentially address many questions surrounding oxidative stress and telomere attrition observed in various disease phenotypes including prostate cancer and diabetes.
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Taniguchi Y, Kikukawa Y, Sasaki S. Discrimination between 8-oxo-2'-deoxyguanosine and 2'-deoxyguanosine in DNA by the single nucleotide primer extension reaction with adap triphosphate. Angew Chem Int Ed Engl 2015; 54:5147-51. [PMID: 25727406 DOI: 10.1002/anie.201412086] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/12/2015] [Indexed: 12/16/2022]
Abstract
The adenosine derivative of 2-oxo-1,3-diazaphenoxazine (Adap) exhibits a superb ability to recognize and form base pairs with 8-oxo-2'-deoxyguanosine (8-oxo-dG) in duplex DNA. In this study, the triphosphate of Adap (dAdapTP) was synthesized and tested for single nucleotide incorporation into primer strands using the Klenow Fragment. The efficiency of dAdapTP incorporation into 8-oxo-dG-containing templates was more than 36-fold higher than with dG-containing templates, and provides better discrimination than does the incorporation of natural 2'-deoxyadenosine triphosphate (dATP). The selective incorporation of dAdapTP into 8-oxo-dG templates was therefore applied to the detection of 8-oxo-dG in human telomeric DNA sequences extracted from H2 O2 -treated HeLa cells. The enzymatic incorporation of dAdapTP into 8-oxo-dG-containing templates may provide a novel basis for sequencing oxidative DNA damage in the genome.
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Affiliation(s)
- Yosuke Taniguchi
- Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan).
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Chaichompoo P, Pattanapanyasat K, Winichagoon P, Fucharoen S, Svasti S. Accelerated telomere shortening in β-thalassemia/HbE patients. Blood Cells Mol Dis 2015; 55:173-9. [PMID: 25631622 DOI: 10.1016/j.bcmd.2015.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 01/11/2015] [Indexed: 11/24/2022]
Abstract
β-Thalassemia/HbE disease is caused by a defective β-globin synthesis that leads to accumulation of excess unbound α-globins, and consequently oxidative stress, ineffective erythropoiesis and chronic anemia. Cell replication and oxidative stress are factors contributing to erosion of telomeres responsible for maintaining genomic stability and cell replication capability. In this study, the rate of telomere shortening in β-thalassemia/HbE patients was compared to the rate of telomere shortening in normal individuals. Telomere length was determined from peripheral blood mononuclear cells of 43 β-thalassemia/HbE patients and 22 normal controls using Flow-FISH analysis. The telomere length was shown to be age-dependent in normal group (rs = 0.715, P = 0.002), whereas severity-dependent telomere shortening was observed in the patients. The telomere length of patients who had severe clinical symptoms (10.07 ± 2.15%) was shorter than that of patients who showed mild symptoms (15.59 ± 2.27%), moderate symptoms (14.50 ± 1.41%) and those in the normal group (14.75 ± 3.11%, P < 0.05). Additionally, reticulocyte count and oxidative stress were correlated with telomere length. This indicates that increased oxidative stress and markedly enhanced erythropoiesis in β-thalassemia/HbE patients leads to accelerated telomere erosion in clinically severe patients.
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Affiliation(s)
- Pornthip Chaichompoo
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand; Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Kovit Pattanapanyasat
- Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Pranee Winichagoon
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
| | - Suthat Fucharoen
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
| | - Saovaros Svasti
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand; Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand.
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Oxidative stress induces persistent telomeric DNA damage responsible for nuclear morphology change in mammalian cells. PLoS One 2014; 9:e110963. [PMID: 25354277 PMCID: PMC4212976 DOI: 10.1371/journal.pone.0110963] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 09/22/2014] [Indexed: 02/07/2023] Open
Abstract
One main function of telomeres is to maintain chromosome and genome stability. The rate of telomere shortening can be accelerated significantly by chemical and physical environmental agents. Reactive oxygen species are a source of oxidative stress and can produce modified bases (mainly 8-oxoG) and single strand breaks anywhere in the genome. The high incidence of guanine residues in telomeric DNA sequences makes the telomere a preferred target for oxidative damage. Our aim in this work is to evaluate whether chromosome instability induced by oxidative stress is related specifically to telomeric damage. We treated human primary fibroblasts (MRC-5) in vitro with hydrogen peroxide (100 and 200 µM) for 1 hr and collected data at several time points. To evaluate the persistence of oxidative stress-induced DNA damage up to 24 hrs after treatment, we analysed telomeric and genomic oxidative damage by qPCR and a modified comet assay, respectively. The results demonstrate that the genomic damage is completely repaired, while the telomeric oxidative damage persists. The analysis of telomere length reveals a significant telomere shortening 48 hrs after treatment, leading us to hypothesise that residual telomere damage could be responsible for the telomere shortening observed. Considering the influence of telomere length modulation on genomic stability, we quantified abnormal nuclear morphologies (Nucleoplasmic Bridges, Nuclear Buds and Micronuclei) and observed an increase of chromosome instability in the same time frame as telomere shortening. At subsequent times (72 and 96 hrs), we observed a restoration of telomere length and a reduction of chromosome instability, leaving us to conjecture a correlation between telomere shortening/dysfunction and chromosome instability. We can conclude that oxidative base damage leads to abnormal nuclear morphologies and that telomere dysfunction is an important contributor to this effect.
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74
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Shortened telomere length in white matter oligodendrocytes in major depression: potential role of oxidative stress. Int J Neuropsychopharmacol 2014; 17:1579-89. [PMID: 24967945 DOI: 10.1017/s1461145714000698] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Telomere shortening is observed in peripheral mononuclear cells from patients with major depressive disorder (MDD). Whether this finding and its biological causes impact the health of the brain in MDD is unknown. Brain cells have differing vulnerabilities to biological mechanisms known to play a role in accelerating telomere shortening. Here, two glia cell populations (oligodendrocytes and astrocytes) known to have different vulnerabilities to a key mediator of telomere shortening, oxidative stress, were studied. The two cell populations were separately collected by laser capture micro-dissection of two white matter regions shown previously to demonstrate pathology in MDD patients. Cells were collected from brain donors with MDD at the time of death and age-matched psychiatrically normal control donors (N = 12 donor pairs). Relative telomere lengths in white matter oligodendrocytes, but not astrocytes, from both brain regions were significantly shorter for MDD donors as compared to matched control donors. Gene expression levels of telomerase reverse transcriptase were significantly lower in white matter oligodendrocytes from MDD as compared to control donors. Likewise, the gene expression of oxidative defence enzymes superoxide dismutases (SOD1 and SOD2), catalase (CAT) and glutathione peroxidase (GPX1) were significantly lower in oligodendrocytes from MDD as compared to control donors. No such gene expression changes were observed in astrocytes from MDD donors. These findings suggest that attenuated oxidative stress defence and deficient telomerase contribute to telomere shortening in oligodendrocytes in MDD, and suggest an aetiological link between telomere shortening and white matter abnormalities previously described in MDD.
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Growing up or growing old? Cellular aging linked with testosterone reactivity to stress in youth. Am J Med Sci 2014; 348:92-100. [PMID: 25010187 DOI: 10.1097/maj.0000000000000299] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Given the established relation between testosterone and aging in older adults, we tested whether buccal telomere length (TL), an established cellular biomarker of aging, was associated with testosterone levels in youth. METHODS Children, mean age 10.2 years, were recruited from the greater New Orleans area, and salivary testosterone was measured diurnally and during an acute stressor. Buccal TL was measured using monochrome multiplex quantitative real-time polymerase chain reaction. Testosterone and TL data were available on 77 individuals. The association between buccal TL and testosterone was tested using multivariate generalized estimating equations to account for clustering of children within families. RESULTS Greater peak testosterone levels (β = -0.87, P < 0.01) and slower recovery (β = -0.56, P < 0.01) and reactivity (β = -1.22, P < 0.01) following a social stressor were significantly associated with shorter buccal TL after controlling for parental age at conception, child age, sex, sociodemographic factors and puberty. No association was initially present between diurnal measurements of testosterone or morning basal testosterone levels and buccal TL. Sex significantly moderated the relation between testosterone reactivity and buccal TL. CONCLUSIONS The association between testosterone and buccal TL supports gonadal maturation as a developmentally sensitive biomarker of aging within youth. As stress levels of testosterone were significantly associated with buccal TL, these findings are consistent with the growing literature linking stress exposure and accelerated maturation. The lack of association of diurnal testosterone or morning basal levels with buccal TL bolsters the notion of a shared stress-related maturational mechanism between cellular stress and the hypothalamic pituitary gonadal axis. These data provide novel evidence supporting the interaction of aging, physiologic stress and cellular processes as an underlying mechanism linking negative health outcomes and early life stress.
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Jurk D, Wilson C, Passos JF, Oakley F, Correia-Melo C, Greaves L, Saretzki G, Fox C, Lawless C, Anderson R, Hewitt G, Pender SLF, Fullard N, Nelson G, Mann J, van de Sluis B, Mann DA, von Zglinicki T. Chronic inflammation induces telomere dysfunction and accelerates ageing in mice. Nat Commun 2014; 2:4172. [PMID: 24960204 PMCID: PMC4090717 DOI: 10.1038/ncomms5172] [Citation(s) in RCA: 531] [Impact Index Per Article: 53.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 05/20/2014] [Indexed: 12/15/2022] Open
Abstract
Chronic inflammation is associated with normal and pathological ageing. Here we show that chronic, progressive low-grade inflammation induced by knockout of the nfkb1 subunit of the transcription factor NF-κB induces premature ageing in mice. We also show that these mice have reduced regeneration in liver and gut. nfkb1(-/-) fibroblasts exhibit aggravated cell senescence because of an enhanced autocrine and paracrine feedback through NF-κB, COX-2 and ROS, which stabilizes DNA damage. Preferential accumulation of telomere-dysfunctional senescent cells in nfkb1(-/-) tissues is blocked by anti-inflammatory or antioxidant treatment of mice, and this rescues tissue regenerative potential. Frequencies of senescent cells in liver and intestinal crypts quantitatively predict mean and maximum lifespan in both short- and long-lived mice cohorts. These data indicate that systemic chronic inflammation can accelerate ageing via ROS-mediated exacerbation of telomere dysfunction and cell senescence in the absence of any other genetic or environmental factor.
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Affiliation(s)
- Diana Jurk
- Institute for Ageing and Health, Newcastle University, NE4 5PL, UK
| | - Caroline Wilson
- Fibrosis Laboratory, Liver Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - João F. Passos
- Institute for Ageing and Health, Newcastle University, NE4 5PL, UK
| | - Fiona Oakley
- Fibrosis Laboratory, Liver Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | | | - Laura Greaves
- Mitochondrial Research Group, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | | | - Chris Fox
- Fibrosis Laboratory, Liver Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Conor Lawless
- Institute for Ageing and Health, Newcastle University, NE4 5PL, UK
- Institute for Cell and Molecular Biosciences, Newcastle University, Catherine Cookson Building, Framlington Place, Newcastle Upon Tyne NE2 4HH, UK
| | - Rhys Anderson
- Institute for Ageing and Health, Newcastle University, NE4 5PL, UK
| | - Graeme Hewitt
- Institute for Ageing and Health, Newcastle University, NE4 5PL, UK
| | - Sylvia LF Pender
- Faculty of Medicine, University of Southampton. Mailpoint 813, Sir Henry Wellcome Laboratories, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK
| | - Nicola Fullard
- Fibrosis Laboratory, Liver Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Glyn Nelson
- Institute for Ageing and Health, Newcastle University, NE4 5PL, UK
| | - Jelena Mann
- Fibrosis Laboratory, Liver Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Bart van de Sluis
- Molecular Genetics Laboratory, Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Derek A. Mann
- Fibrosis Laboratory, Liver Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- These authors contributed equally to this work
| | - Thomas von Zglinicki
- Institute for Ageing and Health, Newcastle University, NE4 5PL, UK
- These authors contributed equally to this work
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Li M, Völker J, Breslauer KJ, Wilson DM. APE1 incision activity at abasic sites in tandem repeat sequences. J Mol Biol 2014; 426:2183-98. [PMID: 24703901 DOI: 10.1016/j.jmb.2014.03.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 11/25/2022]
Abstract
Repetitive DNA sequences, such as those present in microsatellites and minisatellites, telomeres, and trinucleotide repeats (linked to fragile X syndrome, Huntington disease, etc.), account for nearly 30% of the human genome. These domains exhibit enhanced susceptibility to oxidative attack to yield base modifications, strand breaks, and abasic sites; have a propensity to adopt non-canonical DNA forms modulated by the positions of the lesions; and, when not properly processed, can contribute to genome instability that underlies aging and disease development. Knowledge on the repair efficiencies of DNA damage within such repetitive sequences is therefore crucial for understanding the impact of such domains on genomic integrity. In the present study, using strategically designed oligonucleotide substrates, we determined the ability of human apurinic/apyrimidinic endonuclease 1 (APE1) to cleave at apurinic/apyrimidinic (AP) sites in a collection of tandem DNA repeat landscapes involving telomeric and CAG/CTG repeat sequences. Our studies reveal the differential influence of domain sequence, conformation, and AP site location/relative positioning on the efficiency of APE1 binding and strand incision. Intriguingly, our data demonstrate that APE1 endonuclease efficiency correlates with the thermodynamic stability of the DNA substrate. We discuss how these results have both predictive and mechanistic consequences for understanding the success and failure of repair protein activity associated with such oxidatively sensitive, conformationally plastic/dynamic repetitive DNA domains.
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Affiliation(s)
- Mengxia Li
- Laboratory of Molecular Gerontology, National Institute on Aging Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Jens Völker
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854, USA
| | - Kenneth J Breslauer
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854, USA; Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA.
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78
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Palmieri D, Cafueri G, Mongelli F, Pezzolo A, Pistoia V, Palombo D. Telomere shortening and increased oxidative stress are restricted to venous tissue in patients with varicose veins: A merely local disease? Vasc Med 2014; 19:125-130. [DOI: 10.1177/1358863x14525002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Shortened telomere length (TL) and oxidative stress have been described in several vascular disorders at both the tissue and circulating level. However, to our knowledge, there are no reports about TL associated with varicose vein (VV) disease. This paper aimed to evaluate, at the tissue and circulating level, TL and oxidative stress in VV disease, compared to the corresponding counterparts from abdominal aortic aneurysm (AAA) patients and control healthy subjects. TL was measured using quantitative fluorescence in situ hybridization (Q-FISH). Oxidative stress was evaluated by measuring the malondialdehyde (MDA) concentration by thiobarbituric acid reactive substance/s (TBARS) assay. At the vascular tissue level, VV patients had shortened TL and a high MDA concentration, similarly to AAA patients. Conversely, blood lymphocytes and epidermal cells from VV patients had a TL similar to healthy controls and significantly longer than the same cells from AAA patients. Moreover, the MDA concentration in plasma from VV patients was significantly lower than from the AAA group. Linear regression analysis showed a statistically significant inverse correlation between the blood lymphocyte TL and plasma MDA level. Our results suggest that, unlike AAA, telomere attrition in VV tissue is not a systemic phenomenon but it may be attributable to tissue microenvironment conditions and possibly to high local oxidative stress.
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Affiliation(s)
- Daniela Palmieri
- Vascular and Endovascular Surgery Unit, Research Laboratory of Experimental and Clinical Vascular Biology, DISC, University of Genoa, IRCCS San Martino – IST, Genoa, Italy
| | - Giuseppe Cafueri
- Vascular and Endovascular Surgery Unit, Research Laboratory of Experimental and Clinical Vascular Biology, DISC, University of Genoa, IRCCS San Martino – IST, Genoa, Italy
| | - Francesco Mongelli
- Vascular and Endovascular Surgery Unit, Research Laboratory of Experimental and Clinical Vascular Biology, DISC, University of Genoa, IRCCS San Martino – IST, Genoa, Italy
| | | | - Vito Pistoia
- Laboratory of Oncology, IRCCS Gaslini Hospital, Genoa, Italy
| | - Domenico Palombo
- Vascular and Endovascular Surgery Unit, Research Laboratory of Experimental and Clinical Vascular Biology, DISC, University of Genoa, IRCCS San Martino – IST, Genoa, Italy
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79
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Accelerated aging during chronic oxidative stress: a role for PARP-1. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:680414. [PMID: 24319532 PMCID: PMC3844163 DOI: 10.1155/2013/680414] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/20/2013] [Accepted: 09/23/2013] [Indexed: 12/15/2022]
Abstract
Oxidative stress plays a major role in the pathophysiology of chronic inflammatory disease and it has also been linked to accelerated telomere shortening. Telomeres are specialized structures at the ends of linear chromosomes that protect these ends from degradation and fusion. Telomeres shorten with each cell division eventually leading to cellular senescence. Research has shown that poly(ADP-ribose) polymerase-1 (PARP-1) and subtelomeric methylation play a role in telomere stability. We hypothesized that PARP-1 plays a role in accelerated aging in chronic inflammatory diseases due to its role as coactivator of NF-κb and AP-1. Therefore we evaluated the effect of chronic PARP-1 inhibition (by fisetin and minocycline) in human fibroblasts (HF) cultured under normal conditions and under conditions of chronic oxidative stress, induced by tert-butyl hydroperoxide (t-BHP). Results showed that PARP-1 inhibition under normal culturing conditions accelerated the rate of telomere shortening. However, under conditions of chronic oxidative stress, PARP-1 inhibition did not show accelerated telomere shortening. We also observed a strong correlation between telomere length and subtelomeric methylation status of HF cells. We conclude that chronic PARP-1 inhibition appears to be beneficial in conditions of chronic oxidative stress but may be detrimental under relatively normal conditions.
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80
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Essential role for mammalian apurinic/apyrimidinic (AP) endonuclease Ape1/Ref-1 in telomere maintenance. Proc Natl Acad Sci U S A 2013; 110:17844-9. [PMID: 24127576 DOI: 10.1073/pnas.1304784110] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The major mammalian apurinic/apyrimidinic endonuclease Ape1 is a multifunctional protein operating in protection of cells from oxidative stress via its DNA repair, redox, and transcription regulatory activities. The importance of Ape1 has been marked by previous work demonstrating its requirement for viability in mammalian cells. However, beyond a requirement for Ape1-dependent DNA repair activity, deeper molecular mechanisms of the fundamental role of Ape1 in cell survival have not been defined. Here, we report that Ape1 is an essential factor stabilizing telomeric DNA, and its deficiency is associated with telomere dysfunction and segregation defects in immortalized cells maintaining telomeres by either the alternative lengthening of telomeres pathway (U2OS) or telomerase expression (BJ-hTERT), or in normal human fibroblasts (IMR90). Through the expression of Ape1 derivatives with site-specific changes, we found that the DNA repair and N-terminal acetylation domains are required for the Ape1 function at telomeres. Ape1 associates with telomere proteins in U2OS cells, and Ape1 depletion causes dissociation of TRF2 protein from telomeres. Consistent with this effect, we also observed that Ape1 depletion caused telomere shortening in both BJ-hTERT and in HeLa cells. Thus, our study describes a unique and unpredicted role for Ape1 in telomere protection, providing a direct link between base excision DNA repair activities and telomere metabolism.
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81
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Zhou J, Liu M, Fleming AM, Burrows CJ, Wallace SS. Neil3 and NEIL1 DNA glycosylases remove oxidative damages from quadruplex DNA and exhibit preferences for lesions in the telomeric sequence context. J Biol Chem 2013; 288:27263-27272. [PMID: 23926102 DOI: 10.1074/jbc.m113.479055] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The telomeric DNA of vertebrates consists of d(TTAGGG)n tandem repeats, which can form quadruplex DNA structures in vitro and likely in vivo. Despite the fact that the G-rich telomeric DNA is susceptible to oxidation, few biochemical studies of base excision repair in telomeric DNA and quadruplex structures have been done. Here, we show that telomeric DNA containing thymine glycol (Tg), 8-oxo-7,8-dihydroguanine (8-oxoG), guanidinohydantoin (Gh), or spiroiminodihydantoin (Sp) can form quadruplex DNA structures in vitro. We have tested the base excision activities of five mammalian DNA glycosylases (NEIL1, NEIL2, mNeil3, NTH1, and OGG1) on these lesion-containing quadruplex substrates and found that only mNeil3 had excision activity on Tg in quadruplex DNA and that the glycosylase exhibited a strong preference for Tg in the telomeric sequence context. Although Sp and Gh in quadruplex DNA were good substrates for mNeil3 and NEIL1, none of the glycosylases had activity on quadruplex DNA containing 8-oxoG. In addition, NEIL1 but not mNeil3 showed enhanced glycosylase activity on Gh in the telomeric sequence context. These data suggest that one role for Neil3 and NEIL1 is to repair DNA base damages in telomeres in vivo and that Neil3 and Neil1 may function in quadruplex-mediated cellular events, such as gene regulation via removal of damaged bases from quadruplex DNA.
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Affiliation(s)
- Jia Zhou
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, The University of Vermont, Burlington, Vermont 05405-0068
| | - Minmin Liu
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, The University of Vermont, Burlington, Vermont 05405-0068
| | - Aaron M Fleming
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850
| | - Cynthia J Burrows
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850
| | - Susan S Wallace
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, The University of Vermont, Burlington, Vermont 05405-0068.
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82
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Lu J, Vallabhaneni H, Yin J, Liu Y. Deletion of the major peroxiredoxin Tsa1 alters telomere length homeostasis. Aging Cell 2013; 12:635-44. [PMID: 23590194 DOI: 10.1111/acel.12085] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2013] [Indexed: 11/28/2022] Open
Abstract
Reactive oxygen species (ROS) are proposed to play a major role in telomere length alterations during aging. The mechanisms by which ROS disrupt telomeres remain unclear. In Saccharomyces cerevisiae, telomere DNA consists of TG(1-3) repeats, which are maintained primarily by telomerase. Telomere length maintenance can be modulated by the expression level of telomerase subunits and telomerase activity. Additionally, telomerase-mediated telomere repeat addition is negatively modulated by the levels of telomere-bound Rap1-Rif1-Rif2 protein complex. Using a yeast strain defective in the major peroxiredoxin Tsa1 that is involved in ROS neutralization, we have investigated the effect of defective ROS detoxification on telomere DNA, telomerase, telomere-binding proteins, and telomere length. Surprisingly, the tsa1 mutant does not show significant increase in steady-state levels of oxidative DNA lesions at telomeres. The tsa1 mutant displays abnormal telomere lengthening, and reduction in oxidative exposure alleviates this phenotype. The telomere lengthening in the tsa1 cells was abolished by disruption of Est2, subtelomeric DNA, Rap1 C-terminus, or Rif2, but not by Rif1 deletion. Although telomerase expression and activity are not altered, telomere-bound Est2 is increased, while telomere-bound Rap1 is reduced in the tsa1 mutant. We propose that defective ROS scavenging can interfere with pathways that are critical in controlling telomere length homeostasis.
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Affiliation(s)
- Jian Lu
- Laboratory of Molecular Gerontology National Institute on Aging National Institutes of Health 251 Bayview DriveBaltimore MD 21224‐6825USA
| | - Haritha Vallabhaneni
- Laboratory of Molecular Gerontology National Institute on Aging National Institutes of Health 251 Bayview DriveBaltimore MD 21224‐6825USA
| | - Jinhu Yin
- Laboratory of Molecular Gerontology National Institute on Aging National Institutes of Health 251 Bayview DriveBaltimore MD 21224‐6825USA
| | - Yie Liu
- Laboratory of Molecular Gerontology National Institute on Aging National Institutes of Health 251 Bayview DriveBaltimore MD 21224‐6825USA
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83
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Vallabhaneni H, O'Callaghan N, Sidorova J, Liu Y. Defective repair of oxidative base lesions by the DNA glycosylase Nth1 associates with multiple telomere defects. PLoS Genet 2013; 9:e1003639. [PMID: 23874233 PMCID: PMC3715427 DOI: 10.1371/journal.pgen.1003639] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 06/03/2013] [Indexed: 02/07/2023] Open
Abstract
Telomeres are chromosome end structures and are essential for maintenance of genome stability. Highly repetitive telomere sequences appear to be susceptible to oxidative stress-induced damage. Oxidation may therefore have a severe impact on telomere integrity and function. A wide spectrum of oxidative pyrimidine-derivatives has been reported, including thymine glycol (Tg), that are primarily removed by a DNA glycosylase, Endonuclease III-like protein 1 (Nth1). Here, we investigate the effect of Nth1 deficiency on telomere integrity in mice. Nth1 null (Nth1(-/-) ) mouse tissues and primary MEFs harbor higher levels of Endonuclease III-sensitive DNA lesions at telomeric repeats, in comparison to a non-telomeric locus. Furthermore, oxidative DNA damage induced by acute exposure to an oxidant is repaired slowly at telomeres in Nth1(-/-) MEFs. Although telomere length is not affected in the hematopoietic tissues of Nth1(-/-) adult mice, telomeres suffer from attrition and increased recombination and DNA damage foci formation in Nth1(-/-) bone marrow cells that are stimulated ex vivo in the presence of 20% oxygen. Nth1 deficiency also enhances telomere fragility in mice. Lastly, in a telomerase null background, Nth1(-/-) bone marrow cells undergo severe telomere loss at some chromosome ends and cell apoptosis upon replicative stress. These results suggest that Nth1 plays an important role in telomere maintenance and base repair against oxidative stress-induced base modifications. The fact that telomerase deficiency can exacerbate telomere shortening in Nth1 deficient mouse cells supports that base excision repair cooperates with telomerase to maintain telomere integrity.
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Affiliation(s)
- Haritha Vallabhaneni
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
| | | | - Julia Sidorova
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - Yie Liu
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, United States of America
- * E-mail:
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84
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Allgayer J, Kitsera N, von der Lippen C, Epe B, Khobta A. Modulation of base excision repair of 8-oxoguanine by the nucleotide sequence. Nucleic Acids Res 2013; 41:8559-71. [PMID: 23863843 PMCID: PMC3794583 DOI: 10.1093/nar/gkt620] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
8-Oxoguanine (8-oxoG) is a major product of oxidative DNA damage, which induces replication errors and interferes with transcription. By varying the position of single 8-oxoG in a functional gene and manipulating the nucleotide sequence surrounding the lesion, we found that the degree of transcriptional inhibition is independent of the distance from the transcription start or the localization within the transcribed or the non-transcribed DNA strand. However, it is strongly dependent on the sequence context and also proportional to cellular expression of 8-oxoguanine DNA glycosylase (OGG1)-demonstrating that transcriptional arrest does not take place at unrepaired 8-oxoG and proving a causal connection between 8-oxoG excision and the inhibition of transcription. We identified the 5'-CAGGGC[8-oxoG]GACTG-3' motif as having only minimal transcription-inhibitory potential in cells, based on which we predicted that 8-oxoG excision is particularly inefficient in this sequence context. This anticipation was fully confirmed by direct biochemical assays. Furthermore, in DNA containing a bistranded Cp[8-oxoG]/Cp[8-oxoG] clustered lesion, the excision rates differed between the two strands at least by a factor of 9, clearly demonstrating that the excision preference is defined by the DNA strand asymmetry rather than the overall geometry of the double helix or local duplex stability.
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Affiliation(s)
- Julia Allgayer
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University of Mainz, Staudingerweg 5, 55128 Mainz, Germany
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85
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Fleming AM, Burrows CJ. G-quadruplex folds of the human telomere sequence alter the site reactivity and reaction pathway of guanine oxidation compared to duplex DNA. Chem Res Toxicol 2013; 26:593-607. [PMID: 23438298 DOI: 10.1021/tx400028y] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Telomere shortening occurs during oxidative and inflammatory stress with guanine (G) as the major site of damage. In this work, a comprehensive profile of the sites of oxidation and structures of products observed from G-quadruplex and duplex structures of the human telomere sequence was studied in the G-quadruplex folds (hybrid (K(+)), basket (Na(+)), and propeller (K(+) + 50% CH3CN)) resulting from the sequence 5'-(TAGGGT)4T-3' and in an appropriate duplex containing one telomere repeat. Oxidations with four oxidant systems consisting of riboflavin photosensitization, carbonate radical generation, singlet oxygen, and the copper Fenton-like reaction were analyzed under conditions of low product conversion to determine relative reactivity. The one-electron oxidants damaged the 5'-G in G-quadruplexes leading to spiroiminodihydantoin (Sp) and 2,2,4-triamino-2H-oxazol-5-one (Z) as major products as well as 8-oxo-7,8-dihydroguanine (OG) and 5-guanidinohydantoin (Gh) in low relative yields, while oxidation in the duplex context produced damage at the 5'- and middle-Gs of GGG sequences and resulted in Gh being the major product. Addition of the reductant N-acetylcysteine (NAC) to the reaction did not alter the riboflavin-mediated damage sites but decreased Z by 2-fold and increased OG by 5-fold, while not altering the hydantoin ratio. However, NAC completely quenched the CO3(•-) reactions. Singlet oxygen oxidations of the G-quadruplex showed reactivity at all Gs on the exterior faces of G-quartets and furnished the product Sp, while no oxidation was observed in the duplex context under these conditions, and addition of NAC had no effect. Because a long telomere sequence would have higher-order structures of G-quadruplexes, studies were also conducted with 5'-(TAGGGT)8-T-3', and it provided oxidation profiles similar to those of the single G-quadruplex. Lastly, Cu(II)/H2O2-mediated oxidations were found to be indiscriminate in the damage patterns, and 5-carboxamido-5-formamido-2-iminohydantoin (2Ih) was found to be a major duplex product, while nearly equal yields of 2Ih and Sp were observed in G-quadruplex contexts. These findings indicate that the nature of the secondary structure of folded DNA greatly alters both the reactivity of G toward oxidative stress as well as the product outcome and suggest that recognition of damage in telomeric sequences by repair enzymes may be profoundly different from that of B-form duplex DNA.
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Affiliation(s)
- Aaron M Fleming
- Department of Chemistry, University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
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86
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Smith JA, Park S, Krause JS, Banik NL. Oxidative stress, DNA damage, and the telomeric complex as therapeutic targets in acute neurodegeneration. Neurochem Int 2013; 62:764-75. [PMID: 23422879 DOI: 10.1016/j.neuint.2013.02.013] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 02/04/2013] [Accepted: 02/08/2013] [Indexed: 01/19/2023]
Abstract
Oxidative stress has been identified as an important contributor to neurodegeneration associated with acute CNS injuries and diseases such as spinal cord injury (SCI), traumatic brain injury (TBI), and ischemic stroke. In this review, we briefly detail the damaging effects of oxidative stress (lipid peroxidation, protein oxidation, etc.) with a particular emphasis on DNA damage. Evidence for DNA damage in acute CNS injuries is presented along with its downstream effects on neuronal viability. In particular, unchecked oxidative DNA damage initiates a series of signaling events (e.g. activation of p53 and PARP-1, cell cycle re-activation) which have been shown to promote neuronal loss following CNS injury. These findings suggest that preventing DNA damage might be an effective way to promote neuronal survival and enhance neurological recovery in these conditions. Finally, we identify the telomere and telomere-associated proteins (e.g. telomerase) as novel therapeutic targets in the treatment of neurodegeneration due to their ability to modulate the neuronal response to both oxidative stress and DNA damage.
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Affiliation(s)
- Joshua A Smith
- Division of Neurology, Department of Neurosciences, Medical University of South Carolina, 96 Jonathan Lucas St., Clinical Sciences Building Room 309, Charleston, SC 29425, USA.
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87
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Puch CBMD, Barbier E, Sauvaigo S, Gasparutto D, Breton J. Tools and strategies for DNA damage interactome analysis. Mutat Res 2012; 752:72-83. [PMID: 23220222 DOI: 10.1016/j.mrrev.2012.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 11/01/2012] [Accepted: 11/22/2012] [Indexed: 11/26/2022]
Abstract
DNA is the target of multiple endogenous and exogenous agents generating chemical lesions on the double helix. Cellular DNA damage response pathways rely on a myriad of proteins interacting with DNA alterations. The cartography of this interactome currently includes well known actors of chromatin remodelling, DNA repair or proteins hijacked from their natural functions such as transcription factors. In order to go further into the characterisation of these protein networks, proteomics-based methods began to be used in the early 2000s. The strategies are diverse and include mainly (i) damaged DNA molecules used as targets on protein microarrays, (ii) damaged DNA probes used to trap within complex cellular extracts proteins that are then separated and identified by proteomics, (iii) identification of chromatin- bound proteins after a genotoxic stress, or (iv) identification of proteins associated with other proteins already known to be part of DNA damage interactome. All these approaches have already been performed to find new proteins recognizing oxidised bases, abasic sites, strand breaks or crosslinks generated by anticancer drugs such as nitrogen mustards and platinating agents. Identified interactions are generally confirmed using complementary methods such as electromobility shift assays or surface plasmon resonance. These strategies allowed, for example, demonstration of interactions between cisplatin-DNA crosslinks and PARP-1 or the protein complex PTW/PP. The next challenging step will be to understand the biological repercussions of these newly identified interactions which may help to unravel new mechanisms involved in genetic toxicology, discover new cellular responses to anticancer drugs or identify new biomarkers and therapeutic targets.
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Affiliation(s)
| | - Ewa Barbier
- Laboratoire Lésions des Acides Nucléiques, SCIB, UMR-E3 CEA/UJF-Grenoble 1, INAC, 17 rue des Martyrs, Grenoble, F-38054, France
| | - Sylvie Sauvaigo
- Laboratoire Lésions des Acides Nucléiques, SCIB, UMR-E3 CEA/UJF-Grenoble 1, INAC, 17 rue des Martyrs, Grenoble, F-38054, France
| | - Didier Gasparutto
- Laboratoire Lésions des Acides Nucléiques, SCIB, UMR-E3 CEA/UJF-Grenoble 1, INAC, 17 rue des Martyrs, Grenoble, F-38054, France
| | - Jean Breton
- Laboratoire Lésions des Acides Nucléiques, SCIB, UMR-E3 CEA/UJF-Grenoble 1, INAC, 17 rue des Martyrs, Grenoble, F-38054, France; UFR de Pharmacie, Université Joseph Fourier-Grenoble 1, Domaine de la Merci, La Tronche, F-38706, France.
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88
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Monickaraj F, Gokulakrishnan K, Prabu P, Sathishkumar C, Anjana RM, Rajkumar JS, Mohan V, Balasubramanyam M. Convergence of adipocyte hypertrophy, telomere shortening and hypoadiponectinemia in obese subjects and in patients with type 2 diabetes. Clin Biochem 2012; 45:1432-8. [DOI: 10.1016/j.clinbiochem.2012.07.097] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/03/2012] [Accepted: 07/13/2012] [Indexed: 10/28/2022]
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89
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Muraki K, Nyhan K, Han L, Murnane JP. Mechanisms of telomere loss and their consequences for chromosome instability. Front Oncol 2012; 2:135. [PMID: 23061048 PMCID: PMC3463808 DOI: 10.3389/fonc.2012.00135] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 09/19/2012] [Indexed: 12/17/2022] Open
Abstract
The ends of chromosomes in mammals, called telomeres, are composed of a 6-bp repeat sequence, TTAGGG, which is added on by the enzyme telomerase. In combination with a protein complex called shelterin, these telomeric repeat sequences form a cap that protects the ends of chromosomes. Due to insufficient telomerase expression, telomeres shorten gradually with each cell division in human somatic cells, which limits the number of times they can divide. The extensive cell division involved in cancer cell progression therefore requires that cancer cells must acquire the ability to maintain telomeres, either through expression of telomerase, or through an alternative mechanism involving recombination. It is commonly thought that the source of many chromosome rearrangements in cancer cells is a result of the extensive telomere shortening that occurs prior to the expression of telomerase. However, despite the expression of telomerase, tumor cells can continue to show chromosome instability due to telomere loss. Dysfunctional telomeres in cancer cells can result from oncogene-induced replication stress, which results in double-strand breaks (DSBs) at fragile sites, including telomeres. DSBs near telomeres are especially prone to chromosome rearrangements, because telomeric regions are deficient in DSB repair. The deficiency in DSB repair near telomeres is also an important mechanism for ionizing radiation-induced replicative senescence in normal human cells. In addition, DSBs near telomeres can result in chromosome instability in mouse embryonic stem cells, suggesting that telomere loss can contribute to heritable chromosome rearrangements. Consistent with this possibility, telomeric regions in humans are highly heterogeneous, and chromosome rearrangements near telomeres are commonly involved in human genetic disease. Understanding the mechanisms of telomere loss will therefore provide important insights into both human cancer and genetic disease.
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Affiliation(s)
- Keiko Muraki
- Department of Radiation Oncology, University of California at San Francisco San Francisco, CA, USA
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90
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Thilagavathi J, Venkatesh S, Dada R. Telomere length in reproduction. Andrologia 2012; 45:289-304. [DOI: 10.1111/and.12008] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2012] [Indexed: 01/22/2023] Open
Affiliation(s)
- J. Thilagavathi
- Laboratory for Molecular Reproduction and Genetics; Department of Anatomy; All India Institute of Medical Sciences; New Delhi; India
| | - S. Venkatesh
- Laboratory for Molecular Reproduction and Genetics; Department of Anatomy; All India Institute of Medical Sciences; New Delhi; India
| | - R. Dada
- Laboratory for Molecular Reproduction and Genetics; Department of Anatomy; All India Institute of Medical Sciences; New Delhi; India
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91
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Singh DK, Ghosh AK, Croteau DL, Bohr VA. RecQ helicases in DNA double strand break repair and telomere maintenance. Mutat Res 2012; 736:15-24. [PMID: 21689668 PMCID: PMC3368089 DOI: 10.1016/j.mrfmmm.2011.06.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/19/2011] [Accepted: 06/02/2011] [Indexed: 10/24/2022]
Abstract
Organisms are constantly exposed to various environmental insults which could adversely affect the stability of their genome. To protect their genomes against the harmful effect of these environmental insults, organisms have evolved highly diverse and efficient repair mechanisms. Defective DNA repair processes can lead to various kinds of chromosomal and developmental abnormalities. RecQ helicases are a family of evolutionarily conserved, DNA unwinding proteins which are actively engaged in various DNA metabolic processes, telomere maintenance and genome stability. Bacteria and lower eukaryotes, like yeast, have only one RecQ homolog, whereas higher eukaryotes including humans possess multiple RecQ helicases. These multiple RecQ helicases have redundant and/or non-redundant functions depending on the types of DNA damage and DNA repair pathways. Humans have five different RecQ helicases and defects in three of them cause autosomal recessive diseases leading to various kinds of cancer predisposition and/or aging phenotypes. Emerging evidence also suggests that the RecQ helicases have important roles in telomere maintenance. This review mainly focuses on recent knowledge about the roles of RecQ helicases in DNA double strand break repair and telomere maintenance which are important in preserving genome integrity.
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Affiliation(s)
| | | | - Deborah L. Croteau
- Laboratory of Molecular Gerontology, Biomedical Research Center, 251 Bayview Boulevard, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Vilhelm A. Bohr
- Laboratory of Molecular Gerontology, Biomedical Research Center, 251 Bayview Boulevard, National Institute on Aging, NIH, Baltimore, MD 21224, USA
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92
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Aubert G, Baerlocher GM, Vulto I, Poon SS, Lansdorp PM. Collapse of telomere homeostasis in hematopoietic cells caused by heterozygous mutations in telomerase genes. PLoS Genet 2012; 8:e1002696. [PMID: 22661914 PMCID: PMC3355073 DOI: 10.1371/journal.pgen.1002696] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 03/20/2012] [Indexed: 01/03/2023] Open
Abstract
Telomerase activity is readily detectable in extracts from human hematopoietic stem and progenitor cells, but appears unable to maintain telomere length with proliferation in vitro and with age in vivo. We performed a detailed study of the telomere length by flow FISH analysis in leukocytes from 835 healthy individuals and 60 individuals with reduced telomerase activity. Healthy individuals showed a broad range in average telomere length in granulocytes and lymphocytes at any given age. The average telomere length declined with age at a rate that differed between age-specific breakpoints and between cell types. Gender differences between leukocyte telomere lengths were observed for all cell subsets studied; interestingly, this trend could already be detected at birth. Heterozygous carriers for mutations in either the telomerase reverse transcriptase (hTERT) or the telomerase RNA template (hTERC) gene displayed striking and comparable telomere length deficits. Further, non-carrier relatives of such heterozygous individuals had somewhat shorter leukocyte telomere lengths than expected; this difference was most profound for granulocytes. Failure to maintain telomere homeostasis as a result of partial telomerase deficiency is thought to trigger cell senescence or cell death, eventually causing tissue failure syndromes. Our data are consistent with these statements and suggest that the likelihood of similar processes occurring in normal individuals increases with age. Our work highlights the essential role of telomerase in the hematopoietic system and supports the notion that telomerase levels in hematopoietic cells, while limiting and unable to prevent overall telomere shortening, are nevertheless crucial to maintain telomere homeostasis with age. Human blood cells all originate from a common precursor, the hematopoietic stem cell. Telomerase, the enzyme responsible for adding telomere repeats to chromosome ends, is active in human hematopoietic stem cells but appears unable to maintain a constant telomere length with age. We first document the telomere length of different blood cell subsets from 835 healthy individuals between birth and 100 years, to delineate the normal rate of telomere attrition with age. Telomere lengths of blood cells were found to be slightly longer in women than in men, from birth and throughout life. We then compared this reference data to the telomere length in similar blood cell subsets from individuals with reduced telomerase activity as a result of a mutation in one of the genes encoding telomerase and from their direct relatives. Strikingly short telomeres were found in telomerase-deficient individuals, consistent with their cellular pathology and disease susceptibility, and somewhat shorter telomeres than expected were found in cells of relatives with normal telomerase maintenance. Our data can be used as a reference for blood cell telomere length in studies of normal and accelerated aging.
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Affiliation(s)
- Geraldine Aubert
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Gabriela M. Baerlocher
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Experimental Hematology, Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Irma Vulto
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Steven S. Poon
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Peter M. Lansdorp
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Division of Hematology, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
- * E-mail: ;
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93
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Cafueri G, Parodi F, Pistorio A, Bertolotto M, Ventura F, Gambini C, Bianco P, Dallegri F, Pistoia V, Pezzolo A, Palombo D. Endothelial and smooth muscle cells from abdominal aortic aneurysm have increased oxidative stress and telomere attrition. PLoS One 2012; 7:e35312. [PMID: 22514726 PMCID: PMC3325957 DOI: 10.1371/journal.pone.0035312] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 03/13/2012] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Abdominal aortic aneurysm (AAA) is a complex multi-factorial disease with life-threatening complications. AAA is typically asymptomatic and its rupture is associated with high mortality rate. Both environmental and genetic risk factors are involved in AAA pathogenesis. Aim of this study was to investigate telomere length (TL) and oxidative DNA damage in paired blood lymphocytes, aortic endothelial cells (EC), vascular smooth muscle cells (VSMC), and epidermal cells from patients with AAA in comparison with matched controls. METHODS TL was assessed using a modification of quantitative (Q)-FISH in combination with immunofluorescence for CD31 or α-smooth muscle actin to detect EC and VSMC, respectively. Oxidative DNA damage was investigated by immunofluorescence staining for 7, 8-dihydro-8-oxo-2'-deoxyguanosine (8-oxo-dG). RESULTS AND CONCLUSIONS Telomeres were found to be significantly shortened in EC, VSMC, keratinocytes and blood lymphocytes from AAA patients compared to matched controls. 8-oxo-dG immunoreactivity, indicative of oxidative DNA damage, was detected at higher levels in all of the above cell types from AAA patients compared to matched controls. Increased DNA double strand breaks were detected in AAA patients vs controls by nuclear staining for γ-H2AX histone. There was statistically significant inverse correlation between TL and accumulation of oxidative DNA damage in blood lymphocytes from AAA patients. This study shows for the first time that EC and VSMC from AAA have shortened telomeres and oxidative DNA damage. Similar findings were obtained with circulating lymphocytes and keratinocytes, indicating the systemic nature of the disease. Potential translational implications of these findings are discussed.
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Affiliation(s)
- Giuseppe Cafueri
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
| | - Federica Parodi
- Laboratory of Oncology, IRCCS Gaslini Hospital, Genoa, Italy
| | - Angela Pistorio
- Epidemiology and Biostatistics Unit, IRCCS Gaslini Hospital, Genoa, Italy
| | - Maria Bertolotto
- Department of Internal Medicine, University of Genoa, Genoa, Italy
| | | | - Claudio Gambini
- Laboratory of Pathology, IRCCS Gaslini Hospital, Genoa, Italy
| | - Paolo Bianco
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Franco Dallegri
- Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Vito Pistoia
- Laboratory of Oncology, IRCCS Gaslini Hospital, Genoa, Italy
| | - Annalisa Pezzolo
- Laboratory of Oncology, IRCCS Gaslini Hospital, Genoa, Italy
- * E-mail:
| | - Domenico Palombo
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
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94
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A qPCR-based assay to quantify oxidized guanine and other FPG-sensitive base lesions within telomeric DNA. Biotechniques 2012; 51:403-11. [PMID: 22150331 DOI: 10.2144/000113788] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 11/11/2011] [Indexed: 11/23/2022] Open
Abstract
Telomere shortening is an important risk factor for cancer and accelerated aging. However, it is becoming evident that oxidatively damaged DNA within the telomere sequence may also cause telomere dysfunction. Here we describe a reliable, cost-effective quantitative PCR (qPCR)-based method to measure the amount of oxidized residues within telomeric DNA that are recognized and excised by formamidopyridine DNA glycosylase (FPG). We also report that in an in vitro model of oxidative stress oxidized base lesions measured using this method are more prevalent within telomeric sequences. Furthermore, this method is sufficiently sensitive to detect changes in oxidative stress induced by zinc deficiency and hydrogen peroxide within the physiological range.
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95
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Monickaraj F, Aravind S, Gokulakrishnan K, Sathishkumar C, Prabu P, Prabu D, Mohan V, Balasubramanyam M. Accelerated aging as evidenced by increased telomere shortening and mitochondrial DNA depletion in patients with type 2 diabetes. Mol Cell Biochem 2012; 365:343-50. [PMID: 22411737 DOI: 10.1007/s11010-012-1276-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/24/2012] [Indexed: 12/13/2022]
Abstract
Although shortened telomeres were shown associated with several risk factors of diabetes, there is lack of data on their relationship with mitochondrial dysfunction. Therefore, we compared the relationship between telomere length and mitochondrial DNA (mtDNA) content in patients with type 2 diabetes mellitus (T2DM; n = 145) and in subjects with normal glucose tolerance (NGT; n = 145). Subjects were randomly recruited from the Chennai Urban Rural Epidemiology Study. mtDNA content and telomere length were assessed by Real-Time PCR. Malonodialdehyde, a marker of lipid peroxidation was measured by thiobarbituric acid reactive substances (TBARS) using fluorescence methodology. Adiponectin levels were measured by radioimmunoassay. Oxidative stress as determined by lipid peroxidation (TBARS) was significantly (p < 0.001) higher in patients with T2DM compared to NGT subjects. In contrast, the mean telomere length, adiponectin and mtDNA content were significantly (p < 0.001) lower in patients with T2DM compared to NGT subjects. Telomere length was positively correlated with adiponectin, HDL, mtDNA content and good glycemic/lipid control and negatively correlated with adiposity and insulin resistance. On regression analysis, shortened telomeres showed significant association with T2DM even after adjusting for waist circumference, insulin resistance, triglyceride, HDL, adiponectin, mtDNA & TBARS. mtDNA depletion showed significant association with T2DM after adjusting for waist circumference and adiponectin but lost its significance when further adjusted for telomere length, TBARS and insulin resistance. Our study emphasizes the clustering of accelerated aging features viz., shortened telomeres, decreased mtDNA content, hypoadiponectinemia, low HDL, and increased oxidative stress in Asian Indian type 2 diabetes patients.
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Affiliation(s)
- Finny Monickaraj
- Department of Cell and Molecular Biology, Madras Diabetes Research Foundation and Dr. Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-Communicable Diseases Prevention and Control, IDF Centre of Education, Gopalapuram, Chennai 600 086, Tamilnadu, India
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96
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Miller AS, Balakrishnan L, Buncher NA, Opresko PL, Bambara RA. Telomere proteins POT1, TRF1 and TRF2 augment long-patch base excision repair in vitro. Cell Cycle 2012; 11:998-1007. [PMID: 22336916 PMCID: PMC3323798 DOI: 10.4161/cc.11.5.19483] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 12/13/2022] Open
Abstract
Human telomeres consist of multiple tandem hexameric repeats, each containing a guanine triplet. Guanosine-rich clusters are highly susceptible to oxidative base damage, necessitating base excision repair (BER). Previous demonstration of enhanced strand displacement synthesis by the BER component DNA polymerase β in the presence of telomere protein TRF2 suggests that telomeres employ long-patch (LP) BER. Earlier analyses in vitro showed that efficiency of BER reactions is reduced in the DNA-histone environment of chromatin. Evidence presented here indicates that BER is promoted at telomeres. We found that the three proteins that contact telomere DNA, POT1, TRF1 and TRF2, enhance the rate of individual steps of LP-BER and stimulate the complete reconstituted LP-BER pathway. Thought to protect telomere DNA from degradation, these proteins still apparently evolved to allow selective access of repair proteins.
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Affiliation(s)
- Adam S Miller
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
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97
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Delaney S, Jarem DA, Volle CB, Yennie CJ. Chemical and biological consequences of oxidatively damaged guanine in DNA. Free Radic Res 2012; 46:420-41. [PMID: 22239655 DOI: 10.3109/10715762.2011.653968] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Of the four native nucleosides, 2'-deoxyguanosine (dGuo) is most easily oxidized. Two lesions derived from dGuo are 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (Fapy)∙dGuo. Furthermore, while steady-state levels of 8-oxodGuo can be detected in genomic DNA, it is also known that 8-oxodGuo is more easily oxidized than dGuo. Thus, 8-oxodGuo is susceptible to further oxidation to form several hyperoxidized dGuo products. This review addresses the structural impact, the mutagenic and genotoxic potential, and biological implications of oxidatively damaged DNA, in particular 8-oxodGuo, Fapy∙dGuo, and the hyperoxidized dGuo products.
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Affiliation(s)
- Sarah Delaney
- Department of Chemistry, Brown University, Providence, RI 02912, USA.
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98
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Jeppesen DK, Bohr VA, Stevnsner T. DNA repair deficiency in neurodegeneration. Prog Neurobiol 2011; 94:166-200. [PMID: 21550379 DOI: 10.1016/j.pneurobio.2011.04.013] [Citation(s) in RCA: 236] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/18/2011] [Accepted: 04/22/2011] [Indexed: 01/17/2023]
Abstract
Deficiency in repair of nuclear and mitochondrial DNA damage has been linked to several neurodegenerative disorders. Many recent experimental results indicate that the post-mitotic neurons are particularly prone to accumulation of unrepaired DNA lesions potentially leading to progressive neurodegeneration. Nucleotide excision repair is the cellular pathway responsible for removing helix-distorting DNA damage and deficiency in such repair is found in a number of diseases with neurodegenerative phenotypes, including Xeroderma Pigmentosum and Cockayne syndrome. The main pathway for repairing oxidative base lesions is base excision repair, and such repair is crucial for neurons given their high rates of oxygen metabolism. Mismatch repair corrects base mispairs generated during replication and evidence indicates that oxidative DNA damage can cause this pathway to expand trinucleotide repeats, thereby causing Huntington's disease. Single-strand breaks are common DNA lesions and are associated with the neurodegenerative diseases, ataxia-oculomotor apraxia-1 and spinocerebellar ataxia with axonal neuropathy-1. DNA double-strand breaks are toxic lesions and two main pathways exist for their repair: homologous recombination and non-homologous end-joining. Ataxia telangiectasia and related disorders with defects in these pathways illustrate that such defects can lead to early childhood neurodegeneration. Aging is a risk factor for neurodegeneration and accumulation of oxidative mitochondrial DNA damage may be linked with the age-associated neurodegenerative disorders Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. Mutation in the WRN protein leads to the premature aging disease Werner syndrome, a disorder that features neurodegeneration. In this article we review the evidence linking deficiencies in the DNA repair pathways with neurodegeneration.
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Affiliation(s)
- Dennis Kjølhede Jeppesen
- Danish Centre for Molecular Gerontology and Danish Aging Research Center, University of Aarhus, Department of Molecular Biology, Aarhus, Denmark
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