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FOXO3a Mediates Homologous Recombination Repair (HRR) via Transcriptional Activation of MRE11, BRCA1, BRIP1, and RAD50. Molecules 2022; 27:molecules27238623. [PMID: 36500714 PMCID: PMC9741359 DOI: 10.3390/molecules27238623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/23/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
To test whether homologous recombination repair (HRR) depends on FOXO3a, a cellular aging model of human dermal fibroblast (HDF) and tet-on flag-h-FOXO3a transgenic mice were studied. HDF cells transfected with over-expression of wt-h-FOXO3a increased the protein levels of MRE11, BRCA1, BRIP1, and RAD50, while knock-down with siFOXO3a decreased them. The protein levels of MRE11, BRCA1, BRIP1, RAD50, and RAD51 decreased during cellular aging. Chromatin immunoprecipitation (ChIP) assay was performed on FOXO3a binding accessibility to FOXO consensus sites in human MRE11, BRCA1, BRIP1, and RAD50 promoters; the results showed FOXO3a binding decreased during cellular aging. When the tet-on flag-h-FOXO3a mice were administered doxycycline orally, the protein and mRNA levels of flag-h-FOXO3a, MRE11, BRCA1, BRIP1, and RAD50 increased in a doxycycline-dose-dependent manner. In vitro HRR assays were performed by transfection with an HR vector and I-SceI vector. The mRNA levels of the recombined GFP increased after doxycycline treatment in MEF but not in wt-MEF, and increased in young HDF comparing to old HDF, indicating that FOXO3a activates HRR. Overall, these results demonstrate that MRE11, BRCA1, BRIP1, and RAD50 are transcriptional target genes for FOXO3a, and HRR activity is increased via transcriptional activation of MRE11, BRCA1, BRIP1, and RAD50 by FOXO3a.
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2
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Swift ML, Sell C, Azizkhan-Clifford J. DNA damage-induced degradation of Sp1 promotes cellular senescence. GeroScience 2021; 44:683-698. [PMID: 34550526 PMCID: PMC9135943 DOI: 10.1007/s11357-021-00456-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 09/07/2021] [Indexed: 11/28/2022] Open
Abstract
Persistent DNA damage (genotoxic stress) triggers signaling cascades that drive cells into apoptosis or senescence to avoid replicating a damaged genome. Sp1 has been found to play a role in double strand break (DSB) repair, and a link between Sp1 and aging has also been established, where Sp1 protein, but not RNA, levels decrease with age. Interestingly, inhibition ATM reverses the age-related degradation of Sp1, suggesting that DNA damage signaling is involved in senescence-related degradation of Sp1. Proteasomal degradation of Sp1 in senescent cells is mediated via sumoylation, where sumoylation of Sp1 on lysine 16 is increased in senescent cells. Taking into consideration our previous findings that Sp1 is phosphorylated by ATM in response to DNA damage and that proteasomal degradation of Sp1 at DSBs is also mediated by its sumoylation and subsequent interaction with RNF4, we investigated the potential contribution of Sp1’s role as a DSB repair factor in mediating cellular senescence. We report here that Sp1 expression is decreased with a concomitant increase in senescence markers in response to DNA damage. Mutation of Sp1 at serine 101 to create an ATM phospho-null mutant, or mutation of lysine 16 to create a sumo-null mutant, prevents the sumoylation and subsequent proteasomal degradation of Sp1 and results in a decrease in senescence. Conversely, depletion of Sp1 or mutation of Sp1 to create an ATM phosphomimetic results in premature degradation of Sp1 and an increase in senescence markers. These data link a loss of genomic stability with senescence through the action of a DNA damage repair factor.
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Affiliation(s)
- Michelle L Swift
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, 245 N 15th Street, MS497, Philadelphia, PA, 19102, USA
| | - Christian Sell
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, 245 N 15th Street, MS497, Philadelphia, PA, 19102, USA
| | - Jane Azizkhan-Clifford
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, 245 N 15th Street, MS497, Philadelphia, PA, 19102, USA.
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3
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Dialynas G, Delabaere L, Chiolo I. Arp2/3 and Unc45 maintain heterochromatin stability in Drosophila polytene chromosomes. Exp Biol Med (Maywood) 2019; 244:1362-1371. [PMID: 31364400 PMCID: PMC6880141 DOI: 10.1177/1535370219862282] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/18/2019] [Indexed: 12/31/2022] Open
Abstract
Repairing DNA double-strand breaks is particularly challenging in pericentromeric heterochromatin, where the abundance of repeated sequences exacerbates the risk of ectopic recombination. In Drosophila Kc cells, accurate homologous recombination repair of heterochromatic double-strand breaks relies on the relocalization of repair sites to the nuclear periphery before Rad51 recruitment and strand invasion. This movement is driven by Arp2/3-dependent nuclear actin filaments and myosins’ ability to walk along them. Conserved mechanisms enable the relocalization of heterochromatic repair sites in mouse cells, and defects in these pathways lead to massive ectopic recombination in heterochromatin and chromosome rearrangements. In Drosophila polytene chromosomes, extensive DNA movement is blocked by a stiff structure of chromosome bundles. Repair pathways in this context are poorly characterized, and whether heterochromatic double-strand breaks relocalize in these cells is unknown. Here, we show that damage in heterochromatin results in relaxation of the heterochromatic chromocenter, consistent with a dynamic response. Arp2/3, the Arp2/3 activator Scar, and the myosin activator Unc45, are required for heterochromatin stability in polytene cells, suggesting that relocalization enables heterochromatin repair also in this tissue. Together, these studies reveal critical roles for actin polymerization and myosin motors in heterochromatin repair and genome stability across different organisms and tissue types.
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Affiliation(s)
- George Dialynas
- Department of Molecular and Computational Biology,
University
of Southern California, Los Angeles
90089, USA
| | - Laetitia Delabaere
- Department of Molecular and Computational Biology,
University
of Southern California, Los Angeles
90089, USA
| | - Irene Chiolo
- Department of Molecular and Computational Biology,
University
of Southern California, Los Angeles
90089, USA
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4
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Caridi CP, Plessner M, Grosse R, Chiolo I. Nuclear actin filaments in DNA repair dynamics. Nat Cell Biol 2019; 21:1068-1077. [PMID: 31481797 PMCID: PMC6736642 DOI: 10.1038/s41556-019-0379-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 07/24/2019] [Indexed: 02/06/2023]
Abstract
Recent development of innovative tools for live imaging of actin filaments (F-actin) enabled the detection of surprising nuclear structures responding to various stimuli, challenging previous models that actin is substantially monomeric in the nucleus. We review these discoveries, focusing on double-strand break (DSB) repair responses. These studies revealed a remarkable network of nuclear filaments and regulatory mechanisms coordinating chromatin dynamics with repair progression and led to a paradigm shift by uncovering the directed movement of repair sites.
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Affiliation(s)
| | - Matthias Plessner
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg im Breisgau, Germany
- CIBSS - Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Robert Grosse
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg im Breisgau, Germany
- CIBSS - Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Irene Chiolo
- Molecular and Computational Biology Department, University of Southern California, Los Angeles, CA, USA.
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5
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Abstract
DNA double-strand breaks (DSBs) are particularly challenging to repair in pericentromeric heterochromatin because of the increased risk of aberrant recombination in highly repetitive sequences. Recent studies have identified specialized mechanisms enabling 'safe' homologous recombination (HR) repair in heterochromatin. These include striking nuclear actin filaments (F-actin) and myosins that drive the directed motion of repair sites to the nuclear periphery for 'safe' repair. Here, we summarize our current understanding of the mechanisms involved, and propose how they might operate in the context of a phase-separated environment.
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6
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Caridi PC, Delabaere L, Zapotoczny G, Chiolo I. And yet, it moves: nuclear and chromatin dynamics of a heterochromatic double-strand break. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0291. [PMID: 28847828 PMCID: PMC5577469 DOI: 10.1098/rstb.2016.0291] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2017] [Indexed: 12/15/2022] Open
Abstract
Heterochromatin is mostly composed of repeated DNA sequences prone to aberrant recombination. How cells maintain the stability of these sequences during double-strand break (DSB) repair has been a long-standing mystery. Studies in Drosophila cells revealed that faithful homologous recombination repair of heterochromatic DSBs relies on the striking relocalization of repair sites to the nuclear periphery before Rad51 recruitment and repair progression. Here, we summarize our current understanding of this response, including the molecular mechanisms involved, and conserved pathways in mammalian cells. We will highlight important similarities with pathways identified in budding yeast for repair of other types of repeated sequences, including rDNA and short telomeres. We will also discuss the emerging role of chromatin composition and regulation in heterochromatin repair progression. Together, these discoveries challenged previous assumptions that repair sites are substantially static in multicellular eukaryotes, that heterochromatin is largely inert in the presence of DSBs, and that silencing and compaction in this domain are obstacles to repair. This article is part of the themed issue ‘Chromatin modifiers and remodellers in DNA repair and signalling’.
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Affiliation(s)
- P Christopher Caridi
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Laetitia Delabaere
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Grzegorz Zapotoczny
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Irene Chiolo
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
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7
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3D Genome Organization Influences the Chromosome Translocation Pattern. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1044:113-133. [PMID: 29956294 DOI: 10.1007/978-981-13-0593-1_8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent imaging, molecular, and computational modeling studies have greatly enhanced our knowledge of how eukaryotic chromosomes are folded in the nuclear space. This work has begun to reveal how 3D genome structure contributes to various DNA-mediated metabolic activities such as replication, transcription, recombination, and repair. Failure of proper DNA repair can lead to the chromosomal translocations observed in human cancers and other diseases. Questions about the role of 3D genome structure in translocation mechanisms have interested scientists for decades. Recent applications of imaging and Chromosome Conformation Capture approaches have clarified the influence of proximal positioning of chromosomal domains and gene loci on the formation of chromosomal translocations. These approaches have revealed the importance of 3D genome structure not only in translocation partner selection, but also in repair efficiency, likelihood of DNA damage, and the biological implications of translocations. This chapter focuses on our current understanding of the role of 3D genome structure in chromosome translocation formation and its potential implications in disease outcome.
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8
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Pustovalova M, Grekhova A, Astrelina Т, Nikitina V, Dobrovolskaya E, Suchkova Y, Kobzeva I, Usupzhanova D, Vorobyeva N, Samoylov A, Bushmanov A, Ozerov IV, Zhavoronkov A, Leonov S, Klokov D, Osipov AN. Accumulation of spontaneous γH2AX foci in long-term cultured mesenchymal stromal cells. Aging (Albany NY) 2017; 8:3498-3506. [PMID: 27959319 PMCID: PMC5270682 DOI: 10.18632/aging.101142] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/03/2016] [Indexed: 01/15/2023]
Abstract
Expansion of mesenchymal stromal/stem cells (MSCs) used in clinical practices may be associated with accumulation of genetic instability. Understanding temporal and mechanistic aspects of this process is important for improving stem cell therapy protocols. We used γH2AX foci as a marker of a genetic instability event and quantified it in MSCs that undergone various numbers of passage (3-22). We found that γH2AX foci numbers increased in cells of late passages, with a sharp increase at passage 16-18. By measuring in parallel foci of ATM phosphorylated at Ser-1981 and their co-localization with γH2AX foci, along with differentiating cells into proliferating and resting by using a Ki67 marker, we conclude that the sharp increase in γH2AX foci numbers was ATM-independent and happened predominantly in proliferating cells. At the same time, gradual and moderate increase in γH2AX foci with passage number seen in both resting and proliferating cells may represent a slow, DNA double-strand break related component of the accumulation of genetic instability in MSCs. Our results provide important information on selecting appropriate passage numbers exceeding which would be associated with substantial risks to a patient-recipient, both with respect to therapeutic efficiency and side-effects related to potential neoplastic transformations due to genetic instability acquired by MSCs during expansion.
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Affiliation(s)
- Margarita Pustovalova
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Anna Grekhova
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Тatiana Astrelina
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Viktoria Nikitina
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Ekaterina Dobrovolskaya
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Yulia Suchkova
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Irina Kobzeva
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Darya Usupzhanova
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Natalia Vorobyeva
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Aleksandr Samoylov
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Andrey Bushmanov
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia
| | - Ivan V Ozerov
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia.,Insilico Medicine, Inc., Emerging Technology Centers, Johns Hopkins University at Eastern, Baltimore, MD 21218, USA
| | - Alex Zhavoronkov
- Insilico Medicine, Inc., Emerging Technology Centers, Johns Hopkins University at Eastern, Baltimore, MD 21218, USA.,Life Sciences Center, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700, Russia
| | - Sergey Leonov
- Life Sciences Center, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700, Russia
| | - Dmitry Klokov
- Canadian Nuclear Laboratories, Chalk River, ON K0J1P0, Canada
| | - Andreyan N Osipov
- State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency (SRC-FMBC), Moscow 123098, Russia.,Insilico Medicine, Inc., Emerging Technology Centers, Johns Hopkins University at Eastern, Baltimore, MD 21218, USA.,Life Sciences Center, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700, Russia
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9
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Kim H, Chang J, Shao L, Han L, Iyer S, Manolagas SC, O'Brien CA, Jilka RL, Zhou D, Almeida M. DNA damage and senescence in osteoprogenitors expressing Osx1 may cause their decrease with age. Aging Cell 2017; 16:693-703. [PMID: 28401730 PMCID: PMC5506444 DOI: 10.1111/acel.12597] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2017] [Indexed: 12/29/2022] Open
Abstract
Age-related bone loss in mice results from a decrease in bone formation and an increase in cortical bone resorption. The former is accounted by a decrease in the number of postmitotic osteoblasts which synthesize the bone matrix and is thought to be the consequence of age-dependent changes in mesenchymal osteoblast progenitors. However, there are no specific markers for these progenitors, and conclusions rely on results from in vitro cultures of mixed cell populations. Moreover, the culprits of such changes remain unknown. Here, we have used Osx1-Cre;TdRFP mice in which osteoprogenitors express the TdRFP fluorescent protein. We report that the number of TdRFP-Osx1 cells, freshly isolated from the bone marrow, declines by more than 50% between 6 and 24 months of age in both female and male mice. Moreover, TdRFP-Osx1 cells from old mice exhibited markers of DNA damage and senescence, such as γH2AX foci, G1 cell cycle arrest, phosphorylation of p53, increased p21CIP1 levels, as well as increased levels of GATA4 and activation of NF-κB - two major stimulators of the senescence-associated secretory phenotype (SASP). Bone marrow stromal cells from old mice also exhibited elevated expression of SASP genes, including several pro-osteoclastogenic cytokines, and increased capacity to support osteoclast formation. These changes were greatly attenuated by the senolytic drug ABT263. Together, these findings suggest that the decline in bone mass with age is the result of intrinsic defects in osteoprogenitor cells, leading to decreased osteoblast numbers and increased support of osteoclast formation.
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Affiliation(s)
- Ha‐Neui Kim
- Division of Endocrinology and MetabolismCenter for Osteoporosis and Metabolic Bone DiseasesUniversity of Arkansas for Medical SciencesLittle RockARUSA
- Central Arkansas Veterans Healthcare SystemLittle RockARUSA
| | - Jianhui Chang
- Department of Pharmaceutical SciencesUniversity of Arkansas for Medical SciencesLittle RockARUSA
| | - Lijian Shao
- Department of Pharmaceutical SciencesUniversity of Arkansas for Medical SciencesLittle RockARUSA
| | - Li Han
- Division of Endocrinology and MetabolismCenter for Osteoporosis and Metabolic Bone DiseasesUniversity of Arkansas for Medical SciencesLittle RockARUSA
- Central Arkansas Veterans Healthcare SystemLittle RockARUSA
| | - Srividhya Iyer
- Division of Endocrinology and MetabolismCenter for Osteoporosis and Metabolic Bone DiseasesUniversity of Arkansas for Medical SciencesLittle RockARUSA
- Central Arkansas Veterans Healthcare SystemLittle RockARUSA
| | - Stavros C. Manolagas
- Division of Endocrinology and MetabolismCenter for Osteoporosis and Metabolic Bone DiseasesUniversity of Arkansas for Medical SciencesLittle RockARUSA
- Central Arkansas Veterans Healthcare SystemLittle RockARUSA
| | - Charles A. O'Brien
- Division of Endocrinology and MetabolismCenter for Osteoporosis and Metabolic Bone DiseasesUniversity of Arkansas for Medical SciencesLittle RockARUSA
- Central Arkansas Veterans Healthcare SystemLittle RockARUSA
| | - Robert L. Jilka
- Division of Endocrinology and MetabolismCenter for Osteoporosis and Metabolic Bone DiseasesUniversity of Arkansas for Medical SciencesLittle RockARUSA
- Central Arkansas Veterans Healthcare SystemLittle RockARUSA
| | - Daohong Zhou
- Department of Pharmaceutical SciencesUniversity of Arkansas for Medical SciencesLittle RockARUSA
| | - Maria Almeida
- Division of Endocrinology and MetabolismCenter for Osteoporosis and Metabolic Bone DiseasesUniversity of Arkansas for Medical SciencesLittle RockARUSA
- Central Arkansas Veterans Healthcare SystemLittle RockARUSA
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10
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Delabaere L, Ertl HA, Massey DJ, Hofley CM, Sohail F, Bienenstock EJ, Sebastian H, Chiolo I, LaRocque JR. Aging impairs double-strand break repair by homologous recombination in Drosophila germ cells. Aging Cell 2017; 16:320-328. [PMID: 28000382 PMCID: PMC5334535 DOI: 10.1111/acel.12556] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2016] [Indexed: 12/23/2022] Open
Abstract
Aging is characterized by genome instability, which contributes to cancer formation and cell lethality leading to organismal decline. The high levels of DNA double-strand breaks (DSBs) observed in old cells and premature aging syndromes are likely a primary source of genome instability, but the underlying cause of their formation is still unclear. DSBs might result from higher levels of damage or repair defects emerging with advancing age, but repair pathways in old organisms are still poorly understood. Here, we show that premeiotic germline cells of young and old flies have distinct differences in their ability to repair DSBs by the error-free pathway homologous recombination (HR). Repair of DSBs induced by either ionizing radiation (IR) or the endonuclease I-SceI is markedly defective in older flies. This correlates with a remarkable reduction in HR repair measured with the DR-white DSB repair reporter assay. Strikingly, most of this repair defect is already present at 8 days of age. Finally, HR defects correlate with increased expression of early HR components and increased recruitment of Rad51 to damage in older organisms. Thus, we propose that the defect in the HR pathway for germ cells in older flies occurs following Rad51 recruitment. These data reveal that DSB repair defects arise early in the aging process and suggest that HR deficiencies are a leading cause of genome instability in germ cells of older animals.
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Affiliation(s)
- Laetitia Delabaere
- Molecular and Computational Biology Department; University of Southern California; Los Angeles CA 90089 USA
| | - Henry A. Ertl
- Department of Human Science; Georgetown University Medical Center; Washington DC 20057 USA
| | - Dashiell J. Massey
- Department of Human Science; Georgetown University Medical Center; Washington DC 20057 USA
| | - Carolyn M. Hofley
- Department of Human Science; Georgetown University Medical Center; Washington DC 20057 USA
| | - Faraz Sohail
- Department of Human Science; Georgetown University Medical Center; Washington DC 20057 USA
| | - Elisa J. Bienenstock
- Department of Human Science; Georgetown University Medical Center; Washington DC 20057 USA
- College of Public Service & Community Solutions; Arizona State University; Phoenix AZ 85004 USA
| | - Hans Sebastian
- Molecular and Computational Biology Department; University of Southern California; Los Angeles CA 90089 USA
| | - Irene Chiolo
- Molecular and Computational Biology Department; University of Southern California; Los Angeles CA 90089 USA
| | - Jeannine R. LaRocque
- Department of Human Science; Georgetown University Medical Center; Washington DC 20057 USA
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11
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Xu L, Wang Y, Liu Q, Luo H, Zhong X, Li Y. [Role of Autophagy in the Radiosensitivity of Human Lung Adenocarcinoma A549 Cells]. ZHONGGUO FEI AI ZA ZHI = CHINESE JOURNAL OF LUNG CANCER 2017; 19:799-804. [PMID: 27978864 PMCID: PMC5973450 DOI: 10.3779/j.issn.1009-3419.2016.12.01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
背景与目的 放射治疗是肺癌最重要的治疗手段之一,然而却因放疗抵抗极易导致肿瘤的复发和转移。放疗可诱导肿瘤细胞自噬发生,最新研究也报道,自噬可能与DNA损伤修复过程相关。本研究旨在探讨通过雷帕霉素上调A549细胞自噬,能否增加细胞放疗敏感性,其过程是否与DNA损伤修复过程相关。 方法 以人肺腺癌A549细胞作为实验对象,实验设对照组(N)、单纯放疗组(IR)、雷帕霉素联合放疗组(R+RAPA)。采用Western blot检测γ-H2AX蛋白质、Rad51蛋白质、Ku70/80蛋白质、p62蛋白质、LC3蛋白质表达;电镜检测自噬体形成;细胞克隆形成实验检测细胞存活分数(survival fraction, SF)值。 结果 与单纯放疗组相比,放疗联合雷帕霉素组自噬活性增加,且Rad51、Ku80蛋白质表达减少,细胞增殖能力下降。 结论 通过雷帕霉素上调自噬可增加肺癌细胞放疗敏感性,其机制可能与抑制DNA损伤修复过程相关。
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Affiliation(s)
- Liyao Xu
- Department of Oncology, the First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Yong Wang
- Department of Oncology, the First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Qin Liu
- Department of Respirology, the First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Hui Luo
- Department of Oncology, the First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Xiaojun Zhong
- Department of Oncology, the First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Yong Li
- Department of Oncology, the First Affiliated Hospital of Nanchang University, Nanchang 330006, China
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12
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Amaral N, Ryu T, Li X, Chiolo I. Nuclear Dynamics of Heterochromatin Repair. Trends Genet 2017; 33:86-100. [PMID: 28104289 DOI: 10.1016/j.tig.2016.12.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 01/09/2023]
Abstract
Repairing double-strand breaks (DSBs) is particularly challenging in pericentromeric heterochromatin, where the abundance of repeated sequences exacerbates the risk of ectopic recombination and chromosome rearrangements. Recent studies in Drosophila cells revealed that faithful homologous recombination (HR) repair of heterochromatic DSBs relies on the relocalization of DSBs to the nuclear periphery before Rad51 recruitment. We summarize here the exciting progress in understanding this pathway, including conserved responses in mammalian cells and surprising similarities with mechanisms in yeast that deal with DSBs in distinct sites that are difficult to repair, including other repeated sequences. We will also point out some of the most important open questions in the field and emerging evidence suggesting that deregulating these pathways might have dramatic consequences for human health.
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Affiliation(s)
- Nuno Amaral
- University of Southern California, Molecular and Computational Biology Department, Los Angeles, CA 90089, USA
| | - Taehyun Ryu
- University of Southern California, Molecular and Computational Biology Department, Los Angeles, CA 90089, USA
| | - Xiao Li
- University of Southern California, Molecular and Computational Biology Department, Los Angeles, CA 90089, USA
| | - Irene Chiolo
- University of Southern California, Molecular and Computational Biology Department, Los Angeles, CA 90089, USA.
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13
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Stone D, Niyonzima N, Jerome KR. Genome editing and the next generation of antiviral therapy. Hum Genet 2016; 135:1071-82. [PMID: 27272125 PMCID: PMC5002242 DOI: 10.1007/s00439-016-1686-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Accepted: 05/15/2016] [Indexed: 12/18/2022]
Abstract
Engineered endonucleases such as homing endonucleases (HEs), zinc finger nucleases (ZFNs), Tal-effector nucleases (TALENS) and the RNA-guided engineered nucleases (RGENs or CRISPR/Cas9) can target specific DNA sequences for cleavage, and are proving to be valuable tools for gene editing. Recently engineered endonucleases have shown great promise as therapeutics for the treatment of genetic disease and infectious pathogens. In this review, we discuss recent efforts to use the HE, ZFN, TALEN and CRISPR/Cas9 gene-editing platforms as antiviral therapeutics. We also discuss the obstacles facing gene-editing antiviral therapeutics as they are tested in animal models of disease and transition towards human application.
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Affiliation(s)
- Daniel Stone
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Nixon Niyonzima
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA, USA
| | - Keith R. Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
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Abstract
DNA double-strand breaks (DSBs) are rare, but highly toxic, lesions requiring orchestrated and conserved machinery to prevent adverse consequences, such as cell death and cancer-causing genome structural mutations. DSBs trigger the DNA damage response (DDR) that directs a cell to repair the break, undergo apoptosis, or become senescent. There is increasing evidence that the various endpoints of DSB processing by different cells and tissues are part of the aging phenotype, with each stage of the DDR associated with specific aging pathologies. In this Perspective, we discuss the possibility that DSBs are major drivers of intrinsic aging, highlighting the dynamics of spontaneous DSBs in relation to aging, the distinct age-related pathologies induced by DSBs, and the segmental progeroid phenotypes in humans and mice with genetic defects in DSB repair. A model is presented as to how DSBs could drive some of the basic mechanisms underlying age-related functional decline and death.
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Affiliation(s)
- Ryan R White
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave., Bronx, NY 10461, USA.
| | - Jan Vijg
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave., Bronx, NY 10461, USA.
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15
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Can the response to a platinum-based therapy be predicted by the DNA repair status in non-small cell lung cancer? Cancer Treat Rev 2016; 48:8-19. [DOI: 10.1016/j.ctrv.2016.05.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/04/2016] [Accepted: 05/12/2016] [Indexed: 12/17/2022]
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16
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Li Y, Liu F, Wang Y, Li D, Guo F, Xu L, Zeng Z, Zhong X, Qian K. Rapamycin-induced autophagy sensitizes A549 cells to radiation associated with DNA damage repair inhibition. Thorac Cancer 2016; 7:379-86. [PMID: 27385978 PMCID: PMC4930955 DOI: 10.1111/1759-7714.12332] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 12/14/2015] [Indexed: 01/09/2023] Open
Abstract
Background Autophagy has been reported to increase in cancer cells after radiation. However, it remains unknown whether increased autophagy as a result of radiation affects DNA damage repair and sensitizes cancer cells. In this study, the radiosensitization effect of rapamycin, a mammalian target of rapamycin inhibitor that induces autophagy, on human lung adenocarcinoma A549 cells was investigated. Methods A549 cells were treated with different concentrations of rapamycin. Cell viability was evaluated by methyl‐thiazolyl‐tetrazolium assay. Survival fraction values of A549 cells after radiotherapy were detected by colony formation assay. Autophagosome was observed by a transmission electron microscope. Furthermore, Western blot was employed to examine alterations in autophagy protein LC3 and p62, DNA damage protein γ–H2AX, and DNA damage repair proteins Rad51, Ku70, and Ku80. Rad51, Ku70, and Ku80 messenger ribonucleic acid (mRNA) expression levels were examined by real‐time polymerase chain reaction. Results Rapamycin suppressed A549 cell proliferation in dose and time‐dependent manners. An inhibitory concentration (IC)10 dose of rapamycin could induce autophagy in A549 cells. Rapamycin combined with radiation significantly decreased the colony forming ability of cells, compared with rapamycin or radiation alone. Rapamycin and radiation combined increased γ–H2AX expression levels and decreased Rad51 and Ku80 expression levels, compared with single regimens. However, rapamycin treatment did not induce any change in Rad51, Ku70, and Ku80 mRNA levels, regardless of radiation. Conclusions These findings indicate that increasing autophagy sensitizes lung cancer cells to radiation.
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Affiliation(s)
- Yong Li
- Department of Medical Oncology The First Affiliated Hospital of Nanchang University Nanchang Jiangxi China
| | - Fen Liu
- Critical Care Medicine The First Affiliated Hospital of Nanchang University Nanchang Jiangxi China
| | - Yong Wang
- Department of Medical Oncology The First Affiliated Hospital of Nanchang University Nanchang Jiangxi China
| | - Donghai Li
- Department of Neurosurgery The First Affiliated Hospital of Nanchang University Nanchang Jiangxi China
| | - Fei Guo
- The institute of Burn Research The First Affiliated Hospital of Nanchang University Nanchang Jiangxi China
| | - Liyao Xu
- Department of Medical Oncology The First Affiliated Hospital of Nanchang University Nanchang Jiangxi China
| | - Zhengguo Zeng
- Critical Care Medicine The First Affiliated Hospital of Nanchang University Nanchang Jiangxi China
| | - Xiaojun Zhong
- Department of Medical Oncology The First Affiliated Hospital of Nanchang University Nanchang Jiangxi China
| | - Kejian Qian
- Critical Care Medicine The First Affiliated Hospital of Nanchang University Nanchang Jiangxi China
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17
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Controlled induction of DNA double-strand breaks in the mouse liver induces features of tissue ageing. Nat Commun 2015; 6:6790. [PMID: 25858675 PMCID: PMC4394211 DOI: 10.1038/ncomms7790] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/27/2015] [Indexed: 01/07/2023] Open
Abstract
DNA damage has been implicated in ageing, but direct evidence for a causal relationship is lacking, owing to the difficulty of inducing defined DNA lesions in cells and tissues without simultaneously damaging other biomolecules and cellular structures. Here we directly test whether highly toxic DNA double-strand breaks (DSBs) alone can drive an ageing phenotype using an adenovirus-based system based on tetracycline-controlled expression of the SacI restriction enzyme. We deliver the adenovirus to mice and compare molecular and cellular end points in the liver with normally aged animals. Treated, 3-month-old mice display many, but not all signs of normal liver ageing as early as 1 month after treatment, including ageing pathologies, markers of senescence, fused mitochondria and alterations in gene expression profiles. These results, showing that DSBs alone can cause distinct ageing phenotypes in mouse liver, provide new insights in the role of DNA damage as a driver of tissue ageing. Accumulation of DNA damage is a hallmark of cellular ageing but cause and effect are unclear. Here White et al. induce clean DNA double-strand breaks in the liver of mice using a modified restriction enzyme and demonstrate that DNA damage alone is sufficient to recapitulate some aspects of tissue ageing.
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Renkawitz J, Lademann CA, Jentsch S. Mechanisms and principles of homology search during recombination. Nat Rev Mol Cell Biol 2014; 15:369-83. [PMID: 24824069 DOI: 10.1038/nrm3805] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Homologous recombination is crucial for genome stability and for genetic exchange. Although our knowledge of the principle steps in recombination and its machinery is well advanced, homology search, the critical step of exploring the genome for homologous sequences to enable recombination, has remained mostly enigmatic. However, recent methodological advances have provided considerable new insights into this fundamental step in recombination that can be integrated into a mechanistic model. These advances emphasize the importance of genomic proximity and nuclear organization for homology search and the critical role of homology search mediators in this process. They also aid our understanding of how homology search might lead to unwanted and potentially disease-promoting recombination events.
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Affiliation(s)
- Jörg Renkawitz
- 1] Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. [2] Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria. [3]
| | - Claudio A Lademann
- 1] Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. [2]
| | - Stefan Jentsch
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
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