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Yu HJ, Byun YH, Park CK. Techniques for assessing telomere length: A methodological review. Comput Struct Biotechnol J 2024; 23:1489-1498. [PMID: 38633384 PMCID: PMC11021795 DOI: 10.1016/j.csbj.2024.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 04/19/2024] Open
Abstract
Telomeres are located at the ends of chromosomes and have specific sequences with a distinctive structure that safeguards genes. They possess capping structures that protect chromosome ends from fusion events and ensure chromosome stability. Telomeres shorten in length during each cycle of cell division. When this length reaches a certain threshold, it can lead to genomic instability, thus being implicated in various diseases, including cancer and neurodegenerative disorders. The possibility of telomeres serving as a biomarker for aging and age-related disease is being explored, and their significance is still under study. This is because post-mitotic cells, which are mature cells that do not undergo mitosis, do not experience telomere shortening due to age. Instead, other causes, for example, exposure to oxidative stress, can directly damage the telomeres, causing genomic instability. Nonetheless, a general agreement has been established that measuring telomere length offers valuable insights and forms a crucial foundation for analyzing gene expression and epigenetic data. Numerous approaches have been developed to accurately measure telomere lengths. In this review, we summarize various methods and their advantages and limitations for assessing telomere length.
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Affiliation(s)
- Hyeon Jong Yu
- Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Yoon Hwan Byun
- Department of Neurosurgery, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea
| | - Chul-Kee Park
- Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
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2
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Frydrychová RČ, Konopová B, Peska V, Brejcha M, Sábová M. Telomeres and telomerase: active but complex players in life-history decisions. Biogerontology 2024; 25:205-226. [PMID: 37610666 DOI: 10.1007/s10522-023-10060-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 08/24/2023]
Abstract
Studies on human telomeres have established that telomeres exert a significant influence on lifespan and health of organisms. However, recent research has indicated that the original idea that telomeres affect lifespan in a universal and central manner across all eukaryotic species is an oversimplification. Indeed, findings from a variety of animal species revealed that the role of telomere biology in aging is more subtle and intricate than previously recognized. Here, we show how telomere biology varies depending on the taxon. We also show how telomere biology corresponds to basic life history traits and affects the life table of a species and investments in growth, body size, reproduction, and lifespan; telomeres are hypothesized to shape evolutionary perspectives for species in an active but complex manner. Our evaluation is based on telomere biology data from many examples from throughout the animal kingdom that vary according to the degree of organismal complexity and life history strategies.
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Affiliation(s)
- Radmila Čapková Frydrychová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic.
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, Ceske Budejovice, Czech Republic.
| | - Barbora Konopová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
| | - Vratislav Peska
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 00, Brno, Czech Republic
| | - Miloslav Brejcha
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, Ceske Budejovice, Czech Republic
| | - Michala Sábová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
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Telomere Length: Implications for Atherogenesis. Curr Atheroscler Rep 2023; 25:95-103. [PMID: 36689071 PMCID: PMC9947063 DOI: 10.1007/s11883-023-01082-6] [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] [Accepted: 12/11/2022] [Indexed: 01/24/2023]
Abstract
PURPOSE OF REVIEW The purpose of the study is to explore the evidence linking telomere length with atherosclerotic ischemic disease. RECENT FINDINGS There has been a recent expansion in strategies for measuring telomere length, including analyzing genome sequence data and capitalizing on genomic loci that associate with telomere length. These, together with more established approaches, have been used to generate a more complete picture of telomere length relationships with ischemic disease. Whereas earlier meta-analyses suggested an association between short leukocyte telomeres and ischemic disease, several recent large population studies now provide particularly compelling data, including an association with cardiovascular mortality. In addition, whether short leukocyte telomeres might be causally related to ischemic disease has been interrogated using Mendelian randomization strategies, which point to shorter leukocyte telomeres as a determining risk factor. Importantly however, the wide, interindividual variability in telomere length still means that a single assessment of leukocyte telomere length in an individual does not reliably report on a biological aging process. In this regard, recent multi-tissue analyses of telomere length dynamics are providing both new mechanistic insights into how telomere length and shortening rates may participate in atherogenesis and risk prediction opportunities. The balance of evidence indicates that short leukocyte telomeres confer a risk for atherosclerotic cardiovascular disease. Moreover, an integrated analysis of telomere lengths in leukocytes and other tissues may provide a window into individualized telomere dynamics, raising new prospects for risk management.
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Alzoubi H, Minasi S, Gianno F, Antonelli M, Belardinilli F, Giangaspero F, Jaffrain-Rea ML, Buttarelli FR. Alternative Lengthening of Telomeres (ALT) and Telomerase Reverse Transcriptase Promoter Methylation in Recurrent Adult and Primary Pediatric Pituitary Neuroendocrine Tumors. Endocr Pathol 2022; 33:494-505. [PMID: 34993885 DOI: 10.1007/s12022-021-09702-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/18/2021] [Indexed: 12/14/2022]
Abstract
Neoplastic cells acquire the ability to proliferate endlessly by maintaining telomeres via telomerase, or alternative lengthening of telomeres (ALT). The role of telomere maintenance in pituitary neuroendocrine tumors (PitNETs) has yet to be thoroughly investigated. We analyzed surgical samples of 24 adult recurrent PitNETs (including onset and relapses for 14 of them) and 12 pediatric primary PitNETs. The presence of ALT was assessed using telomere-specific fluorescence in situ hybridization, methylation of telomerase reverse transcriptase promoter (TERTp) by methylation-specific PCR, and ATRX expression by immunohistochemistry. Among the adult recurrent PitNETs, we identified 3/24 (12.5%) ALT-positive cases. ALT was present from the onset and maintained in subsequent relapses, suggesting that this mechanism occurs early in tumorigenesis and is stable during progression. ATRX loss was only seen in one ALT-positive case. Noteworthy, ALT was observed in 3 out of 5 aggressive PitNETs, including two aggressive corticotroph tumors, eventually leading to patient's death. ALT-negative tumors (87.5%) were classified according to their low (29.2%), medium (50%), and high (8.3%) telomere fluorescence intensity, with no significant differences emerging in their molecular, clinical, or pathological characteristics. TERTp methylation was found in 6/24 cases (25%), with a total concordance in methylation status between onset and recurrences, suggesting that this mechanism remains stable throughout disease progression. TERTp methylation did not influence telomere length. In the pediatric cohort of PitNETs, TERTp methylation was also observed in 4/12 cases (33.3%), but no case of ALT activation was observed. In conclusion, ALT is triggered at onset and maintained during tumor progression in a subset of adult PitNETs, suggesting that it could be used for clinical purposes, as a potential predictor of aggressive behavior.
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Affiliation(s)
- Hiba Alzoubi
- Department of Basic Medical Sciences, Faculty of Medicine, Yarmouk University, Irbid, Jordan
| | - Simone Minasi
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
| | - Francesca Gianno
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
- IRCCS Neuromed, Pozzilli, Italy
| | - Manila Antonelli
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
| | | | - Felice Giangaspero
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
- IRCCS Neuromed, Pozzilli, Italy
| | - Marie-Lise Jaffrain-Rea
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
- IRCCS Neuromed, Pozzilli, Italy
| | - Francesca Romana Buttarelli
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy.
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Luxton JJ, McKenna MJ, Lewis AM, Taylor LE, Jhavar SG, Swanson GP, Bailey SM. Telomere Length Dynamics and Chromosomal Instability for Predicting Individual Radiosensitivity and Risk via Machine Learning. J Pers Med 2021; 11:188. [PMID: 33800260 PMCID: PMC8002073 DOI: 10.3390/jpm11030188] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 02/23/2021] [Accepted: 03/02/2021] [Indexed: 12/11/2022] Open
Abstract
The ability to predict a cancer patient's response to radiotherapy and risk of developing adverse late health effects would greatly improve personalized treatment regimens and individual outcomes. Telomeres represent a compelling biomarker of individual radiosensitivity and risk, as exposure can result in dysfunctional telomere pathologies that coincidentally overlap with many radiation-induced late effects, ranging from degenerative conditions like fibrosis and cardiovascular disease to proliferative pathologies like cancer. Here, telomere length was longitudinally assessed in a cohort of fifteen prostate cancer patients undergoing Intensity Modulated Radiation Therapy (IMRT) utilizing Telomere Fluorescence in situ Hybridization (Telo-FISH). To evaluate genome instability and enhance predictions for individual patient risk of secondary malignancy, chromosome aberrations were assessed utilizing directional Genomic Hybridization (dGH) for high-resolution inversion detection. We present the first implementation of individual telomere length data in a machine learning model, XGBoost, trained on pre-radiotherapy (baseline) and in vitro exposed (4 Gy γ-rays) telomere length measurements, to predict post radiotherapy telomeric outcomes, which together with chromosomal instability provide insight into individual radiosensitivity and risk for radiation-induced late effects.
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Affiliation(s)
- Jared J. Luxton
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA; (J.J.L.); (M.J.M.); (A.M.L.); (L.E.T.)
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
| | - Miles J. McKenna
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA; (J.J.L.); (M.J.M.); (A.M.L.); (L.E.T.)
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
| | - Aidan M. Lewis
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA; (J.J.L.); (M.J.M.); (A.M.L.); (L.E.T.)
| | - Lynn E. Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA; (J.J.L.); (M.J.M.); (A.M.L.); (L.E.T.)
| | - Sameer G. Jhavar
- Baylor Scott & White Medical Center, Temple, TX 76508, USA; (S.G.J.); (G.P.S.)
| | - Gregory P. Swanson
- Baylor Scott & White Medical Center, Temple, TX 76508, USA; (S.G.J.); (G.P.S.)
| | - Susan M. Bailey
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA; (J.J.L.); (M.J.M.); (A.M.L.); (L.E.T.)
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
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Minasi S, Baldi C, Gianno F, Antonelli M, Buccoliero AM, Pietsch T, Massimino M, Buttarelli FR. Alternative lengthening of telomeres in molecular subgroups of paediatric high-grade glioma. Childs Nerv Syst 2021; 37:809-818. [PMID: 33128602 PMCID: PMC7875853 DOI: 10.1007/s00381-020-04933-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 10/16/2020] [Indexed: 11/18/2022]
Abstract
PURPOSE The maintenance of telomere length prevents cancer cell senescence and occurs via two mutually exclusive mechanisms: (a) reactivation of telomerase expression and (b) activation of alternative lengthening of telomeres (ALT). ALT is frequently related to alterations on ATRX, a chromatin-remodelling protein. Recent data have identified different molecular subgroups of paediatric high-grade glioma (pHGG) with mutations of H3F3A, TERTp and ATRX; however, differences in telomere length among these molecular subgroups were not thoroughly examined. METHODS We investigated which genetic alterations trigger the ALT mechanism in 52 IDH-wildtype, 1p/19q-wildtype pHGG. Samples were analysed for telomere length using Tel-FISH. ATRX nuclear loss of expression was assessed by IHC, H3F3A and TERTp mutations by DNA sequencing, and TERTp methylation by MS-PCR. RESULTS Mutant H3.3 was found in 21 cases (40.3%): 19.2% with K27M mutation and 21.1% with G34R mutation. All H3.3G34R-mutated cases showed the ALT phenotype (100%); on the opposite, only 40% of the H3.3K27M-mutated showed ALT activation. ATRX nuclear loss was seen in 16 cases (30.7%), associated sometimes with the G34R mutation, and never with the K27M mutation. ATRX nuclear loss was always related to telomere elongation. TERTp C250T mutations were rare (5.4%) and were not associated with high intensity Tel-FISH signals, as TERTp hyper-methylation detected in 21% of the cases. H3.3/ATRX/TERTp-wildtype pHGG revealed all basal levels of telomere length. CONCLUSION Our results show a strong association between H3.3 mutations and ALT, and highlight the different telomeric profiles in histone-defined subgroups: H3.3-G34R mutants always trigger ALT to maintain telomere length, irrespective of ATRX status, whereas only some H3.3-K27M tumours activate ALT. These findings suggest that acquiring the gly34 mutation on H3.3 might suffice to trigger the ALT mechanism.
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Affiliation(s)
- Simone Minasi
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Caterina Baldi
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Francesca Gianno
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Manila Antonelli
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
| | | | - Torsten Pietsch
- Institute of Neuropathology, DGNN Brain Tumour Reference Centre, University of Bonn Medical Centre, Bonn, Germany
| | - Maura Massimino
- Paediatric Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy
| | - Francesca Romana Buttarelli
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy.
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy.
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Culver HR, Sinha J, Prieto TR, Calo CJ, Fairbanks BD, Bowman CN. Click Nucleic Acid–DNA Binding Behavior: Dependence on Length, Sequence, and Ionic Strength. Biomacromolecules 2020; 21:4205-4211. [DOI: 10.1021/acs.biomac.0c00996] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Heidi R. Culver
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Jasmine Sinha
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Tania R. Prieto
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Christopher J. Calo
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Benjamin D. Fairbanks
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Christopher N. Bowman
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Materials Science and Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
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8
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Luo Y, Viswanathan R, Hande MP, Loh AHP, Cheow LF. Massively parallel single-molecule telomere length measurement with digital real-time PCR. SCIENCE ADVANCES 2020; 6:eabb7944. [PMID: 32937369 PMCID: PMC7442360 DOI: 10.1126/sciadv.abb7944] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 07/09/2020] [Indexed: 05/02/2023]
Abstract
Telomere length is a promising biomarker for age-associated diseases and cancer, but there are still substantial challenges to routine telomere analysis in clinics because of the lack of a simple and rapid yet scalable method for measurement. We developed the single telomere absolute-length rapid (STAR) assay, a novel high-throughput digital real-time PCR approach for rapidly measuring the absolute lengths and quantities of individual telomere molecules. We show that this technique provides the accuracy and sensitivity to uncover associations between telomere length distribution and telomere maintenance mechanisms in cancer cell lines and primary tumors. The results indicate that the STAR assay is a powerful tool to enable the use of telomere length distribution as a biomarker in disease and population-wide studies.
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Affiliation(s)
- Yongqiang Luo
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117583, Singapore
- Institute for Health Innovation and Technology, National University of Singapore, Singapore 117599, Singapore
| | - Ramya Viswanathan
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117583, Singapore
- Institute for Health Innovation and Technology, National University of Singapore, Singapore 117599, Singapore
| | - Manoor Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Amos Hong Pheng Loh
- Department of Paediatric Surgery, KK Women's and Children's Hospital, Singapore 229899, Singapore
| | - Lih Feng Cheow
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117583, Singapore.
- Institute for Health Innovation and Technology, National University of Singapore, Singapore 117599, Singapore
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Panasiak L, Dobosz S, Ocalewicz K. Telomere Dynamics in the Diploid and Triploid Rainbow Trout ( Oncorhynchus mykiss) Assessed by Q-FISH Analysis. Genes (Basel) 2020; 11:genes11070786. [PMID: 32668770 PMCID: PMC7397301 DOI: 10.3390/genes11070786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 12/02/2022] Open
Abstract
Changes of telomere length with age were assessed in diploid and triploid rainbow trout (Oncorhynchus mykiss) females in the cross-sectional study using Q-FISH technique. Triploid trout as sterile do not invest an energy in gametogenesis and continue to grow, whereas fertile diploid individuals suffer from declines in growth and survival during sexual maturation. However, triploid and diploid specimens exhibited similar patterns of telomere dynamics. Telomere length in the embryos, larvae and one-year-old juveniles did not change significantly. In the second year after hatching, subadults exhibited substantially shortened telomeres, while significant increase of the telomere length was reported in the three-year-old adults. On the other hand, correlation between telomere length and body size was observed in the triploid, but not in the diploid rainbow trout. Telomere shortening observed in two-year-old subadults may have been associated with the premature period of the fast growth in rainbow trout. Similar pattern of the telomere dynamics reported in the fertile diploids and sterile triploids indicated processes related to reproduction did not affect telomere dynamics in this species. Unexpected increase of the telomere length reported during the third year of life confirmed that in rainbow trout telomeric DNA shortens and lengthens, depending on the developmental stage.
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Affiliation(s)
- Ligia Panasiak
- Department of Marine Biology and Ecology, Institute of Oceanography, Faculty of Oceanography and Geography, University of Gdansk, M. Piłsudskiego 46 Av, 81378 Gdynia, Poland;
| | - Stefan Dobosz
- Department of Salmonid Research, Inland Fisheries Institute in Olsztyn, Rutki, 10719 Olsztyn, Poland;
| | - Konrad Ocalewicz
- Department of Marine Biology and Ecology, Institute of Oceanography, Faculty of Oceanography and Geography, University of Gdansk, M. Piłsudskiego 46 Av, 81378 Gdynia, Poland;
- Correspondence:
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10
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Boguszewska K, Szewczuk M, Urbaniak S, Karwowski BT. Review: immunoassays in DNA damage and instability detection. Cell Mol Life Sci 2019; 76:4689-4704. [PMID: 31342119 PMCID: PMC6858475 DOI: 10.1007/s00018-019-03239-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/30/2019] [Accepted: 07/18/2019] [Indexed: 02/03/2023]
Abstract
The review includes information on the current state of knowledge of immunometric methods with emphasis on the possibility of deoxyribonucleic acid (DNA) damage detection. Beginning with basic immunoassay enzyme-linked immunosorbent assay (ELISA), this review describes methods such as tyramide signal amplification (TSA), enhanced polymer one-step staining (EPOS), and time resolved amplified cryptate emission (TRACE) as improvements of ELISA's developed over time to obtain more accurate results. In the second part of the review, surface plasmon resonance (SPR) and quantum dots (QDs) are presented as the newest outlooks in the context of immunoanalysis of biological material and molecular studies. The aim of this review is to briefly present immunoassays with emphasis on DNA damage detection; therefore, the types of methods are listed and described, types of signal indicators, basic definitions such as antigen and antibody are given. Every method is considered with an exemplary application focusing on DNA studies, DNA damage and instability detection.
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Affiliation(s)
- Karolina Boguszewska
- DNA Damage Laboratory of Food Science Department, Faculty of Pharmacy, Medical University of Lodz, ul. Muszynskiego 1, 90-151, Lodz, Poland.
| | - Michał Szewczuk
- DNA Damage Laboratory of Food Science Department, Faculty of Pharmacy, Medical University of Lodz, ul. Muszynskiego 1, 90-151, Lodz, Poland
| | - Sandra Urbaniak
- DNA Damage Laboratory of Food Science Department, Faculty of Pharmacy, Medical University of Lodz, ul. Muszynskiego 1, 90-151, Lodz, Poland
| | - Bolesław T Karwowski
- DNA Damage Laboratory of Food Science Department, Faculty of Pharmacy, Medical University of Lodz, ul. Muszynskiego 1, 90-151, Lodz, Poland.
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11
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Liu B, Maekawa T, Yoshida K, Ly NH, Inoue K, Hasegawa A, Chatton B, Ogura A, Ishii S. Telomere shortening by transgenerational transmission of TNF-α-induced TERRA via ATF7. Nucleic Acids Res 2019; 47:283-298. [PMID: 30407559 PMCID: PMC6326783 DOI: 10.1093/nar/gky1149] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/30/2018] [Indexed: 12/30/2022] Open
Abstract
Various stresses increase disease susceptibility and accelerate aging, and increasing evidence suggests that these effects can be transmitted over generation. Epidemiological studies suggest that stressors experienced by parents affect the longevity of their offspring, possibly by regulating telomere dynamics. Telomeres are elongated by telomerase and shortened by certain stresses as well as telomere repeat-containing RNA (TERRA), a telomere transcript. However, the mechanism underlying the transgenerational effects is poorly understood. Here, we show that TNF-α, which is induced by various psychological stresses, induces the p38-dependent phosphorylation of ATF7, a stress-responsive chromatin regulator, in mouse testicular germ cells. This caused a release of ATF7 from the TERRA gene promoter in the subtelomeric region, which disrupted heterochromatin and induced TERRA. TERRA was transgenerationally transmitted to zygotes via sperm and caused telomere shortening. These results suggest that ATF7 and TERRA play key roles in paternal stress-induced telomere shortening in the offspring.
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Affiliation(s)
- Binbin Liu
- RIKEN Cluster for Pioneering Research, Tsukuba, Ibaraki 305-0074, Japan
| | - Toshio Maekawa
- RIKEN Cluster for Pioneering Research, Tsukuba, Ibaraki 305-0074, Japan
| | - Keisuke Yoshida
- RIKEN Cluster for Pioneering Research, Tsukuba, Ibaraki 305-0074, Japan
| | - Nhung Hong Ly
- RIKEN Cluster for Pioneering Research, Tsukuba, Ibaraki 305-0074, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Kimiko Inoue
- RIKEN BioResource Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Ayumi Hasegawa
- RIKEN BioResource Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Bruno Chatton
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, BP10413, Illkirch, France
| | - Atsuo Ogura
- RIKEN BioResource Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Shunsuke Ishii
- RIKEN Cluster for Pioneering Research, Tsukuba, Ibaraki 305-0074, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
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12
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Maekawa T, Liu B, Nakai D, Yoshida K, Nakamura KI, Yasukawa M, Koike M, Takubo K, Chatton B, Ishikawa F, Masutomi K, Ishii S. ATF7 mediates TNF-α-induced telomere shortening. Nucleic Acids Res 2019; 46:4487-4504. [PMID: 29490055 PMCID: PMC5961373 DOI: 10.1093/nar/gky155] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 02/20/2018] [Indexed: 12/23/2022] Open
Abstract
Telomeres maintain the integrity of chromosome ends and telomere length is an important marker of aging. The epidemiological studies suggested that many types of stress including psychosocial stress decrease telomere length. However, it remains unknown how various stresses induce telomere shortening. Here, we report that the stress-responsive transcription factor ATF7 mediates TNF-α–induced telomere shortening. ATF7 and telomerase, an enzyme that elongates telomeres, are localized on telomeres via interactions with the Ku complex. In response to TNF-α, which is induced by various stresses including psychological stress, ATF7 was phosphorylated by p38, leading to the release of ATF7 and telomerase from telomeres. Thus, a decrease of ATF7 and telomerase on telomeres in response to stress causes telomere shortening, as observed in ATF7-deficient mice. These findings give credence to the idea that various types of stress might shorten telomere.
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Affiliation(s)
- Toshio Maekawa
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | - Binbin Liu
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan
| | - Daisuke Nakai
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan
| | - Keisuke Yoshida
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | - Ken-Ichi Nakamura
- Research Team for Geriatric Diseases, Tokyo Metropolitan Institute of Gerontology, Sakaecho 35-2, Itabashi-ku, Tokyo 173-0015, Japan
| | - Mami Yasukawa
- Division of Cancer Stem Cell, National Cancer Center Research Institute, Tokyo, Japan
| | - Manabu Koike
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kaiyo Takubo
- Research Team for Geriatric Diseases, Tokyo Metropolitan Institute of Gerontology, Sakaecho 35-2, Itabashi-ku, Tokyo 173-0015, Japan
| | - Bruno Chatton
- Université de Strasbourg, UMR7242 Biotechnologie et Signalisation Cellulaire, Ecole Supérieure de Biotechnologie de Strasbourg, BP10413, Illkirch, France
| | - Fuyuki Ishikawa
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kenkichi Masutomi
- Division of Cancer Stem Cell, National Cancer Center Research Institute, Tokyo, Japan
| | - Shunsuke Ishii
- Laboratory of Molecular Genetics, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan
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13
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Minasi S, Baldi C, Pietsch T, Donofrio V, Pollo B, Antonelli M, Massimino M, Giangaspero F, Buttarelli FR. Telomere elongation via alternative lengthening of telomeres (ALT) and telomerase activation in primary metastatic medulloblastoma of childhood. J Neurooncol 2019; 142:435-444. [PMID: 30830680 DOI: 10.1007/s11060-019-03127-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 02/14/2019] [Indexed: 01/06/2023]
Abstract
PURPOSE Elongation of telomeres is necessary for tumor cell immortalization and senescence escape; neoplastic cells use to alternative pathways to elongate telomeres: telomerase reactivation or a telomerase-independent mechanism termed alternative lengthening of telomeres (ALT). Telomerase and ALT pathway has been explored in adult and pediatric gliomas and medulloblastomas (MDBs); however, these mechanisms were not previously investigated in MDBs metastatic at the onset. Therefore, we analyzed the activation of telomerase and ALT pathway in a homogenous cohort of 43 pediatric metastatic medulloblastomas, to investigate whether telomere elongation could play a role in the biology of metastatic MDB. METHODS We evaluated telomeres length via telomere-specific fluorescence in situ hybridization (Telo-FISH); we assessed nuclear expression of ATRX by immunohistochemistry (IHC). H3F3A and TERT promoter mutations were analyzed by pyrosequencing, while UTSS methylation status was analyzed via methylation-specific-PCR (MS-PCR). RESULTS H3F3A mutations were absent in all MDBs, 30% of samples showed ATRX nuclear loss, 18.2% of cases were characterized by TERT promoter mutations, while 60.9% harboured TERT promoter hyper-methylation in the UTSS region. Elongation of telomeres was found in 42.8% of cases. Metastatic MDBs control telomere elongation via telomerase activation (10.7%), induced by TERT promoter mutations in association with UTSS hyper-methylation, and ALT mechanism (32.1%), triggered by ATRX inactivation. Among non-metastatic MDBs, only 5.9% (1/17) showed ATRX nuclear loss with activation of ALT. CONCLUSIONS Our metastatic cases frequently activate ALT pathway, suggesting that it is a common process for senescence escape in primary metastatic medulloblastomas. Furthermore, the activation of mechanisms for telomere elongation is not restricted to certain molecular subgroups in this high-risk group of MDBs.
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Affiliation(s)
- Simone Minasi
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Caterina Baldi
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Torsten Pietsch
- Institute of Neuropathology, DGNN Brain Tumor Reference Center, University of Bonn Medical Center, Bonn, Germany
| | | | - Bianca Pollo
- Neuropathology Unit, IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Manila Antonelli
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
| | - Maura Massimino
- Pediatric Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy
| | - Felice Giangaspero
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, Sapienza University of Rome, Rome, Italy
- IRCCS Neuromed, Pozzilli, Italy
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14
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Guha M, Srinivasan S, Johnson FB, Ruthel G, Guja K, Garcia-Diaz M, Kaufman BA, Glineburg MR, Fang J, Nakagawa H, Basha J, Kundu T, Avadhani NG. hnRNPA2 mediated acetylation reduces telomere length in response to mitochondrial dysfunction. PLoS One 2018; 13:e0206897. [PMID: 30427907 PMCID: PMC6241121 DOI: 10.1371/journal.pone.0206897] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 10/22/2018] [Indexed: 11/19/2022] Open
Abstract
Telomeres protect against chromosomal damage. Accelerated telomere loss has been associated with premature aging syndromes such as Werner's syndrome and Dyskeratosis Congenita, while, progressive telomere loss activates a DNA damage response leading to chromosomal instability, typically observed in cancer cells and senescent cells. Therefore, identifying mechanisms of telomere length maintenance is critical for understanding human pathologies. In this paper we demonstrate that mitochondrial dysfunction plays a causal role in telomere shortening. Furthermore, hnRNPA2, a mitochondrial stress responsive lysine acetyltransferase (KAT) acetylates telomere histone H4at lysine 8 of (H4K8) and this acetylation is associated with telomere attrition. Cells containing dysfunctional mitochondria have higher telomere H4K8 acetylation and shorter telomeres independent of cell proliferation rates. Ectopic expression of KAT mutant hnRNPA2 rescued telomere length possibly due to impaired H4K8 acetylation coupled with inability to activate telomerase expression. The phenotypic outcome of telomere shortening in immortalized cells included chromosomal instability (end-fusions) and telomerase activation, typical of an oncogenic transformation; while in non-telomerase expressing fibroblasts, mitochondrial dysfunction induced-telomere attrition resulted in senescence. Our findings provide a mechanistic association between dysfunctional mitochondria and telomere loss and therefore describe a novel epigenetic signal for telomere length maintenance.
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Affiliation(s)
- Manti Guha
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Satish Srinivasan
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - F. Bradley Johnson
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Gordon Ruthel
- Penn Vet Imaging Core, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Kip Guja
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, United States of America
| | - Miguel Garcia-Diaz
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, United States of America
| | - Brett A. Kaufman
- Vascular Medicine Institute, University of Pittsburg, Pittsburgh, PA United States of America
| | - M. Rebecca Glineburg
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - JiKang Fang
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Hiroshi Nakagawa
- Department of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Jeelan Basha
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Tapas Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Narayan G. Avadhani
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
- * E-mail:
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15
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Dan J, Rousseau P, Hardikar S, Veland N, Wong J, Autexier C, Chen T. Zscan4 Inhibits Maintenance DNA Methylation to Facilitate Telomere Elongation in Mouse Embryonic Stem Cells. Cell Rep 2018; 20:1936-1949. [PMID: 28834755 DOI: 10.1016/j.celrep.2017.07.070] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/20/2017] [Accepted: 07/25/2017] [Indexed: 11/30/2022] Open
Abstract
Proper telomere length is essential for embryonic stem cell (ESC) self-renewal and pluripotency. Mouse ESCs (mESCs) sporadically convert to a transient totipotent state similar to that of two-cell (2C) embryos to recover shortened telomeres. Zscan4, which exhibits a burst of expression in 2C-like mESCs, is required for telomere extension in these cells. However, the mechanism by which Zscan4 extends telomeres remains elusive. Here, we show that Zscan4 facilitates telomere elongation by inducing global DNA demethylation through downregulation of Uhrf1 and Dnmt1, major components of the maintenance DNA methylation machinery. Mechanistically, Zscan4 recruits Uhrf1 and Dnmt1 and promotes their degradation, which depends on the E3 ubiquitin ligase activity of Uhrf1. Blocking DNA demethylation prevents telomere elongation associated with Zscan4 expression, suggesting that DNA demethylation mediates the effect of Zscan4. Our results define a molecular pathway that contributes to the maintenance of telomere length homeostasis in mESCs.
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Affiliation(s)
- Jiameng Dan
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Philippe Rousseau
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, Québec H3T 1E2, Canada
| | - Swanand Hardikar
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Nicolas Veland
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Jiemin Wong
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Chantal Autexier
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, Québec H3T 1E2, Canada; Division of Experimental Medicine, Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Taiping Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA.
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16
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Abstract
Fluorescence in situ hybridization (FISH) has a wide spectrum of applications in current molecular cytogenetic and cancer research. This is a unique technique that can be used for chromosomal DNA analysis in all cell types, at all stages of the cell cycle, and at molecular resolution. Recent developments in microscopy and imaging systems have allowed quantification of digital FISH images (quantitative FISH or QFISH) and have provided a new way for molecular cytogenetic analysis at single-cell level. QFISH can be applied for studying chromosome imbalances in interphase nuclei or metaphase spreads, measuring relative DNA content at chromosomal loci and identifying parental origin of homologous chromosomes. Here, a QFISH protocol suitable for the majority of DNA probes using the popular US National Institute of Health developed ImageJ software is described.
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Affiliation(s)
- Ivan Y Iourov
- Mental Health Research Center, Zagorodnoe sh. 2, Moscow, 117152, Russia. .,Separated Structural Unit "Clinical Research Institute of Pediatrics" named after Y.E. Veltishev, Russian National Research Medical University named after N.I. Pirogov, Ministry of Health of Russian Federation, Moscow, Russia. .,Moscow State University of Psychology and Education, Moscow, Russia.
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17
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Lai TP, Zhang N, Noh J, Mender I, Tedone E, Huang E, Wright WE, Danuser G, Shay JW. A method for measuring the distribution of the shortest telomeres in cells and tissues. Nat Commun 2017; 8:1356. [PMID: 29116081 PMCID: PMC5676791 DOI: 10.1038/s41467-017-01291-z] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 09/07/2017] [Indexed: 01/23/2023] Open
Abstract
Improved methods to measure the shortest (not just average) telomere lengths (TLs) are needed. We developed Telomere Shortest Length Assay (TeSLA), a technique that detects telomeres from all chromosome ends from <1 kb to 18 kb using small amounts of input DNA. TeSLA improves the specificity and efficiency of TL measurements that is facilitated by user friendly image-processing software to automatically detect and annotate band sizes, calculate average TL, as well as the percent of the shortest telomeres. Compared with other TL measurement methods, TeSLA provides more information about the shortest telomeres. The length of telomeres was measured longitudinally in peripheral blood mononuclear cells during human aging, in tissues during colon cancer progression, in telomere-related diseases such as idiopathic pulmonary fibrosis, as well as in mice and other organisms. The results indicate that TeSLA is a robust method that provides a better understanding of the shortest length of telomeres. Short telomeres are a hallmark of senescence and can result in genomic instability as well as cancer progression. Here, the authors present TeSLA, a technique to accurately detect telomeres under 1 kb in length.
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Affiliation(s)
- Tsung-Po Lai
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Ning Zhang
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA.,Department of Bioinformatics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Jungsik Noh
- Department of Bioinformatics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Ilgen Mender
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Enzo Tedone
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Ejun Huang
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Woodring E Wright
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Gaudenz Danuser
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA.,Department of Bioinformatics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390, USA.
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18
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Tichy ED, Sidibe DK, Tierney MT, Stec MJ, Sharifi-Sanjani M, Hosalkar H, Mubarak S, Johnson FB, Sacco A, Mourkioti F. Single Stem Cell Imaging and Analysis Reveals Telomere Length Differences in Diseased Human and Mouse Skeletal Muscles. Stem Cell Reports 2017; 9:1328-1341. [PMID: 28890163 PMCID: PMC5639167 DOI: 10.1016/j.stemcr.2017.08.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 08/08/2017] [Accepted: 08/11/2017] [Indexed: 12/12/2022] Open
Abstract
Muscle stem cells (MuSCs) contribute to muscle regeneration following injury. In many muscle disorders, the repeated cycles of damage and repair lead to stem cell dysfunction. While telomere attrition may contribute to aberrant stem cell functions, methods to accurately measure telomere length in stem cells from skeletal muscles have not been demonstrated. Here, we have optimized and validated such a method, named MuQ-FISH, for analyzing telomere length in MuSCs from either mice or humans. Our analysis showed no differences in telomere length between young and aged MuSCs from uninjured wild-type mice, but MuSCs isolated from young dystrophic mice exhibited significantly shortened telomeres. In corroboration, we demonstrated that telomere attrition is present in human dystrophic MuSCs, which underscores its importance in diseased regenerative failure. The robust technique described herein provides analysis at a single-cell resolution and may be utilized for other cell types, especially rare populations of cells. MuQ-FISH is a telomere analysis assay of mouse and human muscle stem cells Highly sensitive telomere analysis on small numbers of cells Detection of both telomere length and number of telomere foci with MuQ-FISH assay Telomere analysis is now possible in quiescent and/or cycling stem cells
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Affiliation(s)
- Elisia D Tichy
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, 112A Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6081, USA
| | - David K Sidibe
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, 112A Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6081, USA
| | - Matthew T Tierney
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Michael J Stec
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Maryam Sharifi-Sanjani
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, 112A Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6081, USA
| | - Harish Hosalkar
- Joint Preservation Center, Tricity Medical Center, Joint Preservation & Deformity Correction Center & Traumatic Brain Injury Program, Paradise Valley Hospital, National City, CA 91950, USA
| | - Scott Mubarak
- Department of Orthopedic Surgery, Rady Children's Hospital, 3030 Children's Way, San Diego, CA 92123, USA
| | - F Brad Johnson
- Department of Pathology and Laboratory Medicine, Institute on Aging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alessandra Sacco
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Foteini Mourkioti
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, 112A Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6081, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA 19104, USA.
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19
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Du Y, Chen B. Detection approaches for multidrug resistance genes of leukemia. DRUG DESIGN DEVELOPMENT AND THERAPY 2017; 11:1255-1261. [PMID: 28458519 PMCID: PMC5402920 DOI: 10.2147/dddt.s134529] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Leukemia is a clonal malignant hematopoietic stem cell disease. It is the sixth most lethal cancer and accounts for 4% of all cancers. The main form of treatment for leukemia is chemotherapy. While some cancer types with a higher incidence than leukemia, such as lung and gastric cancer, have shown a sharp decline in mortality rates in recent years, leukemia has not followed this trend. Drug resistance is often regarded as the main clinical obstacle to effective chemotherapy in patients diagnosed with leukemia. Many resistance mechanisms have now been identified, and multidrug resistance (MDR) is considered the most important and prevalent mechanism involved in the failure of chemotherapy in leukemia. In order to reverse MDR and improve leukemia prognosis, effective detection methods are needed to identify drug resistance genes at initial diagnosis. This article provides a comprehensive overview of published approaches for the detection of MDR in leukemia. Identification of relevant MDR genes and methods for early detection of these genes will be needed in order to treat leukemia more effectively.
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Affiliation(s)
- Ying Du
- Department of Hematology and Oncology (Key Department of Jiangsu Medicine), School of Medicine, Zhongda Hospital, Southeast University, Nanjing, Jiangsu Province, People's Republic of China
| | - Baoan Chen
- Department of Hematology and Oncology (Key Department of Jiangsu Medicine), School of Medicine, Zhongda Hospital, Southeast University, Nanjing, Jiangsu Province, People's Republic of China
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20
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Sathitruangsak C, Righolt CH, Klewes L, Tung Chang D, Kotb R, Mai S. Distinct and shared three-dimensional chromosome organization patterns in lymphocytes, monoclonal gammopathy of undetermined significance and multiple myeloma. Int J Cancer 2017; 140:400-410. [PMID: 27711972 PMCID: PMC5132008 DOI: 10.1002/ijc.30461] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 07/11/2016] [Accepted: 09/29/2016] [Indexed: 12/24/2022]
Abstract
The consistent appearance of specific chromosomal translocations in multiple myeloma has suggested that the positioning of chromosomes in the interphase nucleus might play a role in the occurrence of particular chromosomal rearrangements associated with malignant transformation. Using fluorescence in situ hybridization, we have determined the positions of selected chromosome pairs (18 and 19, 9 and 22, 4 and 14, 14 and 16, 11 and 14) in interphase nuclei of myeloma cells compared to normal lymphocytes of treatment-naïve patients. All chromosome pairs were arranged in a nonrandom pattern. Chromosomes commonly involved in myeloma-associated translocations (4 and 14, 14 and 16, 11 and 14) were found in close spatial proximity, and this is correlated with the occurrence of overlapping chromosome territories. The spatial distribution of chromosomes may increase the possibility of chromosomal translocations in multiple myeloma.
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Affiliation(s)
- Chirawadee Sathitruangsak
- Department of Cell BiologyUniversity of Manitoba, Research Institute of Hematology and Oncology, CancerCare ManitobaWinnipegManitobaCanada
- Division of Medical OncologyDepartment of Internal MedicinePrince of Songkla UniversitySongkhlaThailand
| | - Christiaan H. Righolt
- Department of Cell BiologyUniversity of Manitoba, Research Institute of Hematology and Oncology, CancerCare ManitobaWinnipegManitobaCanada
| | - Ludger Klewes
- Department of Cell BiologyUniversity of Manitoba, Research Institute of Hematology and Oncology, CancerCare ManitobaWinnipegManitobaCanada
- Department of Cell BiologyCancerCare Manitoba, Genomic Centre for Cancer Research and Diagnosis (GCCRD)WinnipegManitobaCanada
| | - Doris Tung Chang
- Department of Cell BiologyUniversity of Manitoba, Research Institute of Hematology and Oncology, CancerCare ManitobaWinnipegManitobaCanada
| | - Rami Kotb
- Department of HaematologyCancerCare ManitobaWinnipegManitobaCanada
| | - Sabine Mai
- Department of Cell BiologyUniversity of Manitoba, Research Institute of Hematology and Oncology, CancerCare ManitobaWinnipegManitobaCanada
- Department of Cell BiologyCancerCare Manitoba, Genomic Centre for Cancer Research and Diagnosis (GCCRD)WinnipegManitobaCanada
- Department of Physiology and PathophysiologyUniversity of ManitobaWinnipegManitobaCanada
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21
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Finot F, Kaddour A, Morat L, Mouche I, Zaguia N, Cuceu C, Souverville D, Négrault S, Cariou O, Essahli A, Prigent N, Saul J, Paillard F, Heidingsfelder L, Lafouge P, Al Jawhari M, Hempel WM, El May M, Colicchio B, Dieterlen A, Jeandidier E, Sabatier L, Clements J, M'Kacher R. Genotoxic risk of ethyl-paraben could be related to telomere shortening. J Appl Toxicol 2016; 37:758-771. [DOI: 10.1002/jat.3425] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/01/2016] [Accepted: 11/01/2016] [Indexed: 01/22/2023]
Affiliation(s)
- F. Finot
- Covance Laboratory; 78440 Porcheville France
- Cell Environment; Paris France
| | - A. Kaddour
- Cell Environment; Paris France
- Tunis El Manar University; School of Medicine; Tunis Tunisia
| | - L. Morat
- Radiology and Oncology Laboratory, IRCM, DSV; Commissariat à l'energie atomique (CEA); Fontenay-aux Roses France
| | - I. Mouche
- Covance Laboratory; 78440 Porcheville France
- Cell Environment; Paris France
| | - N. Zaguia
- Radiology and Oncology Laboratory, IRCM, DSV; Commissariat à l'energie atomique (CEA); Fontenay-aux Roses France
| | - C. Cuceu
- Radiology and Oncology Laboratory, IRCM, DSV; Commissariat à l'energie atomique (CEA); Fontenay-aux Roses France
| | | | - S. Négrault
- Covance Laboratory; 78440 Porcheville France
| | - O. Cariou
- Covance Laboratory; 78440 Porcheville France
| | - A. Essahli
- Covance Laboratory; 78440 Porcheville France
| | - N. Prigent
- Covance Laboratory; 78440 Porcheville France
| | - J. Saul
- Covance Laboratories; Yorkshire HG3 1PY UK
| | - F. Paillard
- Covance Laboratory; 78440 Porcheville France
| | | | - P. Lafouge
- Covance Laboratory; 78440 Porcheville France
| | | | - W. M. Hempel
- Radiology and Oncology Laboratory, IRCM, DSV; Commissariat à l'energie atomique (CEA); Fontenay-aux Roses France
| | - M. El May
- Tunis El Manar University; School of Medicine; Tunis Tunisia
| | - B. Colicchio
- Laboratoire MIPS - Groupe IMTI Université de Haute-Alsace; F-68093 Mulhouse France
| | - A. Dieterlen
- Laboratoire MIPS - Groupe IMTI Université de Haute-Alsace; F-68093 Mulhouse France
| | - E. Jeandidier
- Service de génétique Groupe Hospitalier de la Région de Mulhouse et Sud Alsace; 68070 Mulhouse France
| | - L. Sabatier
- Radiology and Oncology Laboratory, IRCM, DSV; Commissariat à l'energie atomique (CEA); Fontenay-aux Roses France
| | | | - R. M'Kacher
- Cell Environment; Paris France
- Radiology and Oncology Laboratory, IRCM, DSV; Commissariat à l'energie atomique (CEA); Fontenay-aux Roses France
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22
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Al-Mayah AHJ, Bright SJ, Bowler DA, Slijepcevic P, Goodwin E, Kadhim MA. Exosome-Mediated Telomere Instability in Human Breast Epithelial Cancer Cells after X Irradiation. Radiat Res 2016; 187:98-106. [PMID: 27959588 DOI: 10.1667/rr14201.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In directly irradiating cells, telomere metabolism is altered and similar effects have been observed in nontargeted cells. Exosomes and their cargo play dominant roles in communicating radiation-induced bystander effects with end points related to DNA damage. Here we report novel evidence that exosomes are also responsible for inducing telomere-related bystander effects. Breast epithelial cancer cells were exposed to either 2 Gy X rays, or exposed to irradiated cell conditioned media (ICCM), or exosomes purified from ICCM. Compared to control cells, telomerase activity decreased in the 2 Gy irradiated cells and both bystander samples after one population doubling. At the first population doubling, telomere length was shorter in the 2 Gy irradiated sample but not in the bystander samples. By 24 population doublings telomerase activity recovered to control levels in all samples; however, the 2 Gy irradiated sample continued to demonstrate short telomeres and both bystander samples acquired shorter telomeres. RNase treatment of exosomes prevented the bystander effects on telomerase and telomere length that were observed at 1 population doubling and 24 population doublings, respectively. Thermal denaturation by boiling eliminated the reduction of telomere length in bystander samples, suggesting that the protein fraction of exosomes also contributes to the telomeric effect. RNase treatment plus boiling abrogated all telomere-related effects in directly irradiated and bystander cell populations. These findings suggest that both proteins and RNAs of exosomes can induce alterations in telomeric metabolism, which can instigate genomic instability in epithelial cancer cells after X-ray irradiation.
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Affiliation(s)
- Ammar H J Al-Mayah
- a Genomic Instability Group, Oxford Brookes University, Gipsy Lane Campus, Headington, Oxford OX3 0BP, United Kingdom
| | - Scott J Bright
- a Genomic Instability Group, Oxford Brookes University, Gipsy Lane Campus, Headington, Oxford OX3 0BP, United Kingdom
| | - Debbie A Bowler
- a Genomic Instability Group, Oxford Brookes University, Gipsy Lane Campus, Headington, Oxford OX3 0BP, United Kingdom
| | - Predrag Slijepcevic
- b Department of Life Sciences, College of Health and Life Sciences, Brunel University, London UB8 3PH, United Kingdom
| | - Edwin Goodwin
- c The New Mexico Consortium, Los Alamos, New Mexico 87544
| | - Munira A Kadhim
- a Genomic Instability Group, Oxford Brookes University, Gipsy Lane Campus, Headington, Oxford OX3 0BP, United Kingdom
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23
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Scheffold A, Holtman IR, Dieni S, Brouwer N, Katz SF, Jebaraj BMC, Kahle PJ, Hengerer B, Lechel A, Stilgenbauer S, Boddeke EWGM, Eggen BJL, Rudolph KL, Biber K. Telomere shortening leads to an acceleration of synucleinopathy and impaired microglia response in a genetic mouse model. Acta Neuropathol Commun 2016; 4:87. [PMID: 27550225 PMCID: PMC4994259 DOI: 10.1186/s40478-016-0364-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 08/11/2016] [Indexed: 12/21/2022] Open
Abstract
Parkinson’s disease is one of the most common neurodegenerative disorders of the elderly and ageing hence described to be a major risk factor. Telomere shortening as a result of the inability to fully replicate the ends of linear chromosomes is one of the hallmarks of ageing. The role of telomere dysfunction in neurological diseases and the ageing brain is not clarified and there is an ongoing discussion whether telomere shortening is linked to Parkinson’s disease. Here we studied a mouse model of Parkinson’s disease (Thy-1 [A30P] α-synuclein transgenic mouse model) in the background of telomere shortening (Terc knockout mouse model). α-synuclein transgenic mice with short telomeres (αSYNtg/tg G3Terc-/-) developed an accelerated disease with significantly decreased survival. This accelerated phenotype of mice with short telomeres was characterized by a declined motor performance and an increased formation of α-synuclein aggregates. Immunohistochemical analysis and mRNA expression studies revealed that the disease end-stage brain stem microglia showed an impaired response in αSYNtg/tg G3Terc-/- microglia animals. These results provide the first experimental data that telomere shortening accelerates α-synuclein pathology that is linked to limited microglia function in the brainstem.
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24
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Seo B, Lee J. Observation and Quantification of Telomere and Repetitive Sequences Using Fluorescence In Situ Hybridization (FISH) with PNA Probes in Caenorhabditis elegans. J Vis Exp 2016:54224. [PMID: 27583462 PMCID: PMC5091719 DOI: 10.3791/54224] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Telomere is a ribonucleoprotein structure that protects chromosomal ends from aberrant fusion and degradation. Telomere length is maintained by telomerase or an alternative pathway, known as alternative lengthening of telomeres (ALT)(1). Recently, C. elegans has emerged as a multicellular model organism for the study of telomere and ALT(2). Visualization of repetitive sequences in the genome is critical in understanding the biology of telomeres. While telomere length can be measured by telomere restriction fragment assay or quantitative PCR, these methods only provide the averaged telomere length. On the contrary, fluorescence in situ hybridization (FISH) can provide the information of the individual telomeres in cells. Here, we provide protocols and representative results of the method to determine telomere length of C. elegans by fluorescent in situ hybridization. This method provides a simple, but powerful, in situ procedure that does not cause noticeable damage to morphology. By using fluorescently labeled peptide nucleic acid (PNA) and digoxigenin-dUTP-labeled probe, we were able to visualize two different repetitive sequences: telomere repeats and template of ALT (TALT) in C. elegans embryos and gonads.
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Affiliation(s)
- Beomseok Seo
- Institute of Molecular Biology and Genetics (IMBG), Seoul National University
| | - Junho Lee
- Institute of Molecular Biology and Genetics (IMBG), Seoul National University; Department of Biological Sciences, Seoul National University; Department of Biophysics and Chemical Biology, Seoul National University;
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25
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Rousseau P, Khondaker S, Zhu S, Lauzon C, Mai S, Autexier C. An intact putative mouse telomerase essential N-terminal domain is necessary for proper telomere maintenance. Biol Cell 2016; 108:96-112. [PMID: 26787169 DOI: 10.1111/boc.201500089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/14/2016] [Indexed: 12/15/2022]
Abstract
BACKGROUND INFORMATION Naturally occurring telomerase reverse transcriptase (TERT) isoforms may regulate telomerase activity, and possibly function independently of telomeres to modulate embryonic stem (ES) cell self-renewal and differentiation. RESULTS We report the characterisation of two novel mouse TERT (mTERT) splice variants, Ins-i1[1-102] (Insi1 for short) and Del-e12[1-40] (Dele12 for short) that have not been previously described. Insi1 represents an in-frame insertion of nucleotides 1-102 from intron 1, encoding a 34 amino acid insertion at amino acid 73. Based on known functions of this region in human and Tetrahymena TERTs, the insertion interrupts the RNA interaction domain 1 implicated in low-affinity RNA binding and the telomerase essential N-terminal domain implicated in DNA substrate interactions. Dele12 contains a 40 nucleotide deletion of exon 12 which generates a premature stop codon, and possible protein lacking the C-terminus. We found Insi1 expressed in adult mouse brain and kidney and Dele12 expressed in adult mouse ovary. Dele12 was inactive in vitro and in mTERT(-/-) ES cells and Insi1 retained 26-48% of telomerase activity reconstituted by wild-type mTERT in vitro and in mTERT(-/-) ES cells. The Insi1 variant exhibited reduced DNA substrate binding in vitro and both variants exhibited a reduction in binding the telomerase RNA, mTR, when expressed in mTERT(-/-) ES cells. Stable expression of Dele12 in the mouse fibroblast CB17 cell line inhibited telomerase activity and slowed cell growth, suggesting a potential dominant-negative effect. Levels of signal-free ends, representing short telomeres, and end-to-end fusions were higher in mTERT(-/-) ES cells expressing mTERT-Insi1 and mTERT-Dele12, compared with levels observed in mTERT(-/-) ES cells expressing wild-type mTERT. In addition, in mTERT(-/-) cells expressing mTERT-Insi1, we observed chromosomes that were products of repeated breakage-bridge-fusion cycles and other telomere dysfunction-related aberrations. CONCLUSION AND SIGNIFICANCE An intact mTERT N-terminus which contributes to mTR binding, DNA binding and telomerase activity is necessary for elongation of short telomeres and the maintenance of functional telomeres. It is reasonable to speculate that relative levels of mTERT-Insi1 may regulate telomere function in specific tissues.
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Affiliation(s)
- Philippe Rousseau
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, H3T 1E2, Canada
| | - Shanjadia Khondaker
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, H3T 1E2, Canada.,Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
| | - Shusen Zhu
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, H3T 1E2, Canada
| | - Catherine Lauzon
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, H3T 1E2, Canada
| | - Sabine Mai
- Manitoba Institute of Cell Biology, University of Manitoba, Manitoba, R3E 0V9, Canada
| | - Chantal Autexier
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, H3T 1E2, Canada.,Division of Experimental Medicine, McGill University, Montréal, Québec, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, Québec, Canada
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26
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Spontaneous tumor development in bone marrow-rescued DNA-PKcs(3A/3A) mice due to dysfunction of telomere leading strand deprotection. Oncogene 2015; 35:3909-18. [PMID: 26616856 PMCID: PMC4885801 DOI: 10.1038/onc.2015.459] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 12/16/2022]
Abstract
Phosphorylation of the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) at the Thr2609 cluster is essential for its complete function in DNA repair and tissue stem cell homeostasis. This phenomenon is demonstrated by congenital bone marrow failure occurring in DNA-PKcs3A/3A mutant mice, which require bone marrow transplantation (BMT) to prevent early mortality. Surprisingly, an increased incidence of spontaneous tumors, especially skin cancer, was observed in adult BMT-rescued DNA-PKcs3A/3A mice. Upon further investigation we found that spontaneous γH2AX foci occurred in DNA-PKcs3A/3A skin biopsies and primary keratinocytes and that these foci overlapped with telomeres during mitosis, indicating impairment of telomere replication and maturation. Consistently, we observed significantly elevated frequencies of telomere fusion events in DNA-PKcs3A/3A cells as compared to wild type and DNA-PKcs knockout cells. In addition, a previously identified DNA-PKcs Thr2609Pro mutation, found in breast cancer, also induces a similar impairment of telomere leading end maturation. Taken together, our current analyses indicate that the functional DNA-PKcs T2609 cluster is required to facilitate telomere leading strand maturation and prevention of genomic instability and cancer development.
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27
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Sishc BJ, Nelson CB, McKenna MJ, Battaglia CLR, Herndon A, Idate R, Liber HL, Bailey SM. Telomeres and Telomerase in the Radiation Response: Implications for Instability, Reprograming, and Carcinogenesis. Front Oncol 2015; 5:257. [PMID: 26636039 PMCID: PMC4656829 DOI: 10.3389/fonc.2015.00257] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/06/2015] [Indexed: 01/06/2023] Open
Abstract
Telomeres are nucleoprotein complexes comprised of tandem arrays of repetitive DNA sequence that serve to protect chromosomal termini from inappropriate degradation, as well as to prevent these natural DNA ends from being recognized as broken DNA (double-strand breaks) and triggering of inappropriate DNA damage responses. Preservation of telomere length requires telomerase, the specialized reverse transcriptase capable of maintaining telomere length via template-mediated addition of telomeric repeats onto the ends of newly synthesized chromosomes. Loss of either end-capping function or telomere length maintenance has been associated with genomic instability or senescence in a variety of settings; therefore, telomeres and telomerase have well-established connections to cancer and aging. It has long been recognized that oxidative stress promotes shortening of telomeres, and that telomerase activity is a radiation-inducible function. However, the effects of ionizing radiation (IR) exposure on telomeres per se are much less well understood and appreciated. To gain a deeper understanding of the roles, telomeres and telomerase play in the response of human cells to IRs of different qualities, we tracked changes in telomeric end-capping function, telomere length, and telomerase activity in panels of mammary epithelial and hematopoietic cell lines exposed to low linear energy transfer (LET) gamma(γ)-rays or high LET, high charge, high energy (HZE) particles, delivered either acutely or at low dose rates. In addition to demonstrating that dysfunctional telomeres contribute to IR-induced mutation frequencies and genome instability, we reveal non-canonical roles for telomerase, in that telomerase activity was required for IR-induced enrichment of mammary epithelial putative stem/progenitor cell populations, a finding also suggestive of cellular reprograming. Taken together, the results reported here establish the critical importance of telomeres and telomerase in the radiation response and, as such, have compelling implications not only for accelerated tumor repopulation following radiation therapy but also for carcinogenic potential following low dose exposures as well, including those of relevance to spaceflight-associated galactic cosmic radiations.
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Affiliation(s)
- Brock J Sishc
- Division of Molecular Radiation Oncology, Department of Radiation Oncology, University of Texas Southwestern Medical Center Dallas , Dallas, TX , USA ; Department of Environmental and Radiological Health Sciences, Colorado State University , Fort Collins, CO , USA
| | - Christopher B Nelson
- Department of Environmental and Radiological Health Sciences, Colorado State University , Fort Collins, CO , USA
| | - Miles J McKenna
- Department of Environmental and Radiological Health Sciences, Colorado State University , Fort Collins, CO , USA
| | - Christine L R Battaglia
- Department of Environmental and Radiological Health Sciences, Colorado State University , Fort Collins, CO , USA
| | - Andrea Herndon
- Department of Environmental and Radiological Health Sciences, Colorado State University , Fort Collins, CO , USA
| | - Rupa Idate
- Department of Environmental and Radiological Health Sciences, Colorado State University , Fort Collins, CO , USA
| | - Howard L Liber
- Department of Environmental and Radiological Health Sciences, Colorado State University , Fort Collins, CO , USA
| | - Susan M Bailey
- Department of Environmental and Radiological Health Sciences, Colorado State University , Fort Collins, CO , USA
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28
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Janson C, Nyhan K, Murnane JP. Replication Stress and Telomere Dysfunction Are Present in Cultured Human Embryonic Stem Cells. Cytogenet Genome Res 2015; 146:251-60. [PMID: 26517359 DOI: 10.1159/000441245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Indexed: 11/19/2022] Open
Abstract
Replication stress causes DNA damage at fragile sites in the genome. DNA damage at telomeres can initiate breakage-fusion-bridge cycles and chromosome instability, which can result in replicative senescence or tumor formation. Little is known about the extent of replication stress or telomere dysfunction in human embryonic stem cells (hESCs). hESCs are grown in culture with the expectation of being used therapeutically in humans, making it important to minimize the levels of replication stress and telomere dysfunction. Here, the hESC line UCSF4 was cultured in a defined medium with growth factor Activin A, exogenous nucleosides, or DNA polymerase inhibitor aphidicolin. We used quantitative fluorescence in situ hybridization to analyze individual telomeres for dysfunction and observed that it can be increased by aphidicolin or Activin A. In contrast, adding exogenous nucleosides relieved dysfunction, suggesting that telomere dysfunction results from replication stress. Whether these findings can be applied to other hESC lines remains to be determined. However, because the loss of telomeres can lead to chromosome instability and cancer, we conclude that hESCs grown in culture for future therapeutic purposes should be routinely checked for replication stress and telomere dysfunction.
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Affiliation(s)
- Christine Janson
- Department of Radiation Oncology, University of California San Francisco, San Francisco, Calif., USA
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29
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Cesare AJ, Heaphy CM, O'Sullivan RJ. Visualization of Telomere Integrity and Function In Vitro and In Vivo Using Immunofluorescence Techniques. CURRENT PROTOCOLS IN CYTOMETRY 2015; 73:12.40.1-12.40.31. [PMID: 26132175 PMCID: PMC4862373 DOI: 10.1002/0471142956.cy1240s73] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In cancer cells, telomere length maintenance occurs largely via the direct synthesis of TTAGGG repeats at chromosome ends by telomerase, or less frequently by the recombination-dependent alternative lengthening of telomeres (ALT) pathway. The latter is characterized by the atypical clustering of telomeres within promyelocytic leukemia (PML) nuclear bodies, which harbor proteins that are linked with DNA repair and recombination activity. For this reason, it is speculated that these associated PML bodies represent the sites of the recombination that maintains telomere length. The protocols described here can be employed for the routine investigation of the structural integrity of telomeres and the association of proteins at telomeres in normal cells, challenged cells, and archived formalin-fixed paraffin-embedded clinical tissue specimens that may have activated the ALT pathway.
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Affiliation(s)
- Anthony J Cesare
- Children's Medical Research Institute, The University of Sydney, Westmead, Australia
| | | | - Roderick J O'Sullivan
- University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania
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30
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Osterwald S, Deeg KI, Chung I, Parisotto D, Wörz S, Rohr K, Erfle H, Rippe K. PML induces compaction, TRF2 depletion and DNA damage signaling at telomeres and promotes their alternative lengthening. J Cell Sci 2015; 128:1887-1900. [DOI: 10.1242/jcs.148296] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
ABSTRACT
The alternative lengthening of telomeres (ALT) mechanism allows cancer cells to escape senescence and apoptosis in the absence of active telomerase. A characteristic feature of this pathway is the assembly of ALT-associated promyelocytic leukemia (PML) nuclear bodies (APBs) at telomeres. Here, we dissected the role of APBs in a human ALT cell line by performing an RNA interference screen using an automated 3D fluorescence microscopy platform and advanced 3D image analysis. We identified 29 proteins that affected APB formation, which included proteins involved in telomere and chromatin organization, protein sumoylation and DNA repair. By integrating and extending these findings, we found that APB formation induced clustering of telomere repeats, telomere compaction and concomitant depletion of the shelterin protein TRF2 (also known as TERF2). These APB-dependent changes correlated with the induction of a DNA damage response at telomeres in APBs as evident by a strong enrichment of the phosphorylated form of the ataxia telangiectasia mutated (ATM) kinase. Accordingly, we propose that APBs promote telomere maintenance by inducing a DNA damage response in ALT-positive tumor cells through changing the telomeric chromatin state to trigger ATM phosphorylation.
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Affiliation(s)
- Sarah Osterwald
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Katharina I. Deeg
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Inn Chung
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Daniel Parisotto
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Stefan Wörz
- Department of Bioinformatics and Functional Genomics, Biomedical Computer Vision Group, University of Heidelberg & DKFZ, BioQuant, IPMB, 69120 Heidelberg, Germany
| | - Karl Rohr
- Department of Bioinformatics and Functional Genomics, Biomedical Computer Vision Group, University of Heidelberg & DKFZ, BioQuant, IPMB, 69120 Heidelberg, Germany
| | - Holger Erfle
- ViroQuant-CellNetworks RNAi Screening Facility, University of Heidelberg & BioQuant, 69120 Heidelberg, Germany
| | - Karsten Rippe
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
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31
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Komosa M, Root H, Meyn MS. Visualization and quantitative analysis of extrachromosomal telomere-repeat DNA in individual human cells by Halo-FISH. Nucleic Acids Res 2015; 43:2152-63. [PMID: 25662602 PMCID: PMC4344523 DOI: 10.1093/nar/gkv091] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Current methods for characterizing extrachromosomal nuclear DNA in mammalian cells do not permit single-cell analysis, are often semi-quantitative and frequently biased toward the detection of circular species. To overcome these limitations, we developed Halo-FISH to visualize and quantitatively analyze extrachromosomal DNA in single cells. We demonstrate Halo-FISH by using it to analyze extrachromosomal telomere-repeat (ECTR) in human cells that use the Alternative Lengthening of Telomeres (ALT) pathway(s) to maintain telomere lengths. We find that GM847 and VA13 ALT cells average ∼80 detectable G/C-strand ECTR DNA molecules/nucleus, while U2OS ALT cells average ∼18 molecules/nucleus. In comparison, human primary and telomerase-positive cells contain <5 ECTR DNA molecules/nucleus. ECTR DNA in ALT cells exhibit striking cell-to-cell variations in number (<20 to >300), range widely in length (<1 to >200 kb) and are composed of primarily G- or C-strand telomere-repeat DNA. Halo-FISH enables, for the first time, the simultaneous analysis of ECTR DNA and chromosomal telomeres in a single cell. We find that ECTR DNA comprises ∼15% of telomere-repeat DNA in GM847 and VA13 cells, but <4% in U2OS cells. In addition to its use in ALT cell analysis, Halo-FISH can facilitate the study of a wide variety of extrachromosomal DNA in mammalian cells.
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Affiliation(s)
- Martin Komosa
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
| | - Heather Root
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada
| | - M Stephen Meyn
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Ontario, M5G 0A4, Canada Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada Department of Paediatrics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
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32
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Pham HH, Murphy CT, Sureshkumar G, Ly DH, Opresko PL, Armitage BA. Cooperative hybridization of γPNA miniprobes to a repeating sequence motif and application to telomere analysis. Org Biomol Chem 2014; 12:7345-7354. [PMID: 25115693 PMCID: PMC4162129 DOI: 10.1039/c4ob00953c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
GammaPNA oligomers having one or two repeats of the sequence AATCCC were designed to hybridize to DNA having one or more repeats of the complementary TTAGGG sequence found in the human telomere. UV melting curves and surface plasmon resonance experiments demonstrate high affinity and cooperativity for hybridization of these miniprobes to DNA having multiple complementary repeats. Fluorescence spectroscopy for Cy3-labeled miniprobes demonstrate increases in fluorescence intensity for assembling multiple short probes on a DNA target compared with fewer longer probes. The fluorescent γPNA miniprobes were then used to stain telomeres in metaphase chromosomes derived from U2OS cells possessing heterogeneous long telomeres and Jurkat cells harboring homogenous short telomeres. The miniprobes yielded comparable fluorescence intensity to a commercially available PNA 18mer probe in U2OS cells, but significantly brighter fluorescence was observed for telomeres in Jurkat cells. These results suggest that γPNA miniprobes can be effective telomere-staining reagents with applications toward analysis of critically short telomeres, which have been implicated in a range of human diseases.
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Affiliation(s)
- Ha H. Pham
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Connor T. Murphy
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Department of Environmental and Occupational Health, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA 15219
| | - Gopalsamy Sureshkumar
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Danith H. Ly
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
| | - Patricia L. Opresko
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Department of Environmental and Occupational Health, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA 15219
| | - Bruce A. Armitage
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
- Center for Nucleic Acids Science and Technology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
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33
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Misenko SM, Bunting SF. Rapid analysis of chromosome aberrations in mouse B lymphocytes by PNA-FISH. J Vis Exp 2014:51806. [PMID: 25177909 PMCID: PMC4540087 DOI: 10.3791/51806] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Defective DNA repair leads to increased genomic instability, which is the root cause of mutations that lead to tumorigenesis. Analysis of the frequency and type of chromosome aberrations in different cell types allows defects in DNA repair pathways to be elucidated. Understanding mammalian DNA repair biology has been greatly helped by the production of mice with knockouts in specific genes. The goal of this protocol is to quantify genomic instability in mouse B lymphocytes. Labeling of the telomeres using PNA-FISH probes (peptide nucleic acid - fluorescent in situ hybridization) facilitates the rapid analysis of genomic instability in metaphase chromosome spreads. B cells have specific advantages relative to fibroblasts, because they have normal ploidy and a higher mitotic index. Short-term culture of B cells therefore enables precise measurement of genomic instability in a primary cell population which is likely to have fewer secondary genetic mutations than what is typically found in transformed fibroblasts or patient cell lines.
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Affiliation(s)
- Sarah M Misenko
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey
| | - Samuel F Bunting
- Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey;
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34
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Sagie S, Ellran E, Katzir H, Shaked R, Yehezkel S, Laevsky I, Ghanayim A, Geiger D, Tzukerman M, Selig S. Induced pluripotent stem cells as a model for telomeric abnormalities in ICF type I syndrome. Hum Mol Genet 2014; 23:3629-40. [PMID: 24549038 DOI: 10.1093/hmg/ddu071] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Human telomeric regions are packaged as constitutive heterochromatin, characterized by extensive subtelomeric DNA methylation and specific histone modifications. ICF (immunodeficiency, centromeric instability, facial anomalies) type I patients carry mutations in DNA methyltransferase 3B (DNMT3B) that methylates de novo repetitive sequences during early embryonic development. ICF type I patient fibroblasts display hypomethylated subtelomeres, abnormally short telomeres and premature senescence. In order to study the molecular mechanism by which the failure to de novo methylate subtelomeres results in accelerated telomere shortening, we generated induced pluripotent stem cells (iPSCs) from 3 ICF type I patients. Telomeres were elongated in ICF-iPSCs during reprogramming, and the senescence phenotype was abolished despite sustained subtelomeric hypomethylation and high TERRA levels. Fibroblast-like cells (FLs) isolated from differentiated ICF-iPSCs maintained abnormally high TERRA levels, and telomeres in these cells shortened at an accelerated rate, leading to early senescence, thus recapitulating the telomeric phenotype of the parental fibroblasts. These findings demonstrate that the abnormal telomere phenotype associated with subtelomeric hypomethylation is overridden in cells expressing telomerase, therefore excluding telomerase inhibition by TERRA as a central mechanism responsible for telomere shortening in ICF syndrome. The data in the current study lend support to the use of ICF-iPSCs for modeling of phenotypic and molecular defects in ICF syndrome and for unraveling the mechanism whereby subtelomeric hypomethylation is linked to accelerated telomeric loss in this syndrome.
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Affiliation(s)
- Shira Sagie
- Laboratory of Molecular Medicine, Rambam Health Care Campus and Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 31096, Israel
| | - Erika Ellran
- Laboratory of Molecular Medicine, Rambam Health Care Campus and Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 31096, Israel
| | - Hagar Katzir
- Laboratory of Molecular Medicine, Rambam Health Care Campus and Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 31096, Israel
| | - Rony Shaked
- Laboratory of Molecular Medicine, Rambam Health Care Campus and Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 31096, Israel
| | - Shiran Yehezkel
- Laboratory of Molecular Medicine, Rambam Health Care Campus and Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 31096, Israel
| | - Ilana Laevsky
- The Sohnis and Forman Families Stem Cell Center, Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 31096, Israel
| | - Alaa Ghanayim
- Computer Science Department, Technion, Haifa 32000, Israel
| | - Dan Geiger
- Computer Science Department, Technion, Haifa 32000, Israel
| | - Maty Tzukerman
- Laboratory of Molecular Medicine, Rambam Health Care Campus and Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 31096, Israel
| | - Sara Selig
- Laboratory of Molecular Medicine, Rambam Health Care Campus and Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 31096, Israel,
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Nakamura KI, Ishikawa N, Izumiyama N, Aida J, Kuroiwa M, Hiraishi N, Fujiwara M, Nakao A, Kawakami T, Poon SS, Matsuura M, Sawabe M, Arai T, Takubo K. Telomere lengths at birth in trisomies 18 and 21 measured by Q-FISH. Gene 2014; 533:199-207. [DOI: 10.1016/j.gene.2013.09.086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 09/19/2013] [Accepted: 09/24/2013] [Indexed: 10/26/2022]
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36
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Basu N, Skinner HG, Litzelman K, Vanderboom R, Baichoo E, Boardman LA. Telomeres and telomere dynamics: relevance to cancers of the GI tract. Expert Rev Gastroenterol Hepatol 2013; 7:733-48. [PMID: 24161135 PMCID: PMC3892561 DOI: 10.1586/17474124.2013.848790] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Aberrations in telomere length and telomere maintenance contribute to cancer development. In this article, we review the basic principles of telomere length in normal and tumor tissue and the presence of the two main telomere maintenance pathways as they pertain to gastrointestinal tract cancer. Peripheral blood telomeres are shorter in patients with many types of gastrointestinal tract cancers. Telomere length in tumor DNA also appears to shorten early in cancer development. Tumor telomere shortening is often accompanied by telomerase activation to protect genetically damaged DNA from normal cell senescence or apoptosis, allowing immortalized but damaged DNA to persist. Alternative lengthening of telomeres is another mechanism used by cancer to maintain telomere length in cancer cells. Telomerase and alternative lengthening of telomeres activators and inhibitors may become important chemopreventive or chemotherapeutic agents as our understanding of telomere biology, specific telomere-related phenotypes and its relationship to carcinogenesis increases.
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Affiliation(s)
- Nivedita Basu
- Division of Gastroenterology and Hepatology Department of Medicine Mayo Clinic 200 First Street SW Rochester, MN 55905 Tel: 507-266-4338; Fax: 507-266-0350
| | - Halcyon G. Skinner
- Department of Population Health Sciences School of Medicine and Public Health University of Wisconsin Madison, WI 53726 Tel: 608-265-4654
| | - Kristin Litzelman
- Department of Population Health Sciences School of Medicine and Public Health University of Wisconsin Madison, WI 53726 Tel: 608-265-4654
| | - Russell Vanderboom
- Division of Gastroenterology and Hepatology Department of Medicine Mayo Clinic 200 First Street SW Rochester, MN 55905 Tel: 507-266-4338; Fax: 507-266-0350
| | - Esha Baichoo
- Division of Gastroenterology and Hepatology Department of Medicine Mayo Clinic 200 First Street SW Rochester, MN 55905 Tel: 507-266-4338; Fax: 507-266-0350
| | - Lisa A. Boardman
- Division of Gastroenterology and Hepatology Department of Medicine Mayo Clinic 200 First Street SW Rochester, MN 55905 Tel: 507-266-4338; Fax: 507-266-0350
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37
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Terai M, Izumiyama-Shimomura N, Aida J, Ishikawa N, Kuroiwa M, Poon SSS, Arai T, Toyoda M, Akutsu H, Umezawa A, Nakamura KI, Takubo K. Investigation of telomere length dynamics in induced pluripotent stem cells using quantitative fluorescence in situ hybridization. Tissue Cell 2013; 45:407-13. [PMID: 23928219 DOI: 10.1016/j.tice.2013.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/08/2013] [Accepted: 07/08/2013] [Indexed: 01/03/2023]
Abstract
Here we attempted to clarify telomere metabolism in parental cells and their derived clonal human induced pluripotent stem cells (iPSCs) at different passages using quantitative fluorescence in situ hybridization (Q-FISH). Our methodology involved estimation of the individual telomere lengths of chromosomal arms in individual cells within each clone in relation to telomere fluorescence units (TFUs) determined by Q-FISH. TFUs were very variable within the same metaphase spread and within the same cell. TFUs of the established iPSCs derived from human amnion (hAM933 iPSCs), expressed as mean values of the median TFUs of 20 karyotypes, were significantly longer than those of the parental cells, although the telomere extension rates varied quite significantly among the clones. Twenty metaphase spreads from hAM933 iPSCs demonstrated no chromosomal instability. The iPSCs established from fetal lung fibroblasts (MRC-5) did not exhibit telomere shortening and chromosomal instability as the number of passages increased. However, the telomeres of other iPSCs derived from MRC-5 became shorter as the number of passages increased, and one (5%) of 20 metaphase spreads showed chromosomal abnormalities including X trisomy at an early stage and all 20 showed abnormalities including X and 12 trisomies at the late stage.
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Affiliation(s)
- Masanori Terai
- Research Team for Geriatric Pathology, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan; Department of Judotherapy, Faculty of Health Sciences, Tokyo Ariake University of Medical and Health Sciences, Tokyo 135-0063, Japan.
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38
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Bertolo A, Mehr M, Janner-Jametti T, Graumann U, Aebli N, Baur M, Ferguson SJ, Stoyanov JV. An in vitro expansion score for tissue-engineering applications with human bone marrow-derived mesenchymal stem cells. J Tissue Eng Regen Med 2013; 10:149-61. [PMID: 23576360 DOI: 10.1002/term.1734] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 01/08/2013] [Accepted: 01/30/2013] [Indexed: 12/24/2022]
Abstract
Human bone marrow-derived mesenchymal stem cells (MSCs) have limited growth potential in vitro and cease to divide due to replicative senescence, which from a tissue-engineering perspective has practical implications, such as defining the correct starting points for differentiation and transplantation. Time spent in culture before the loss of required differentiation potential is different and reflects patient variability, which is a problem for cell expansion. This study aimed to develop a score set which can be used to quantify the senescent state of MSCs and predict whether cells preserve their ability to differentiate to osteogenic, adipogenic and chondrogenic phenotypes, based on colony-forming unit (CFU) assay, population doubling time (PDT), senescence-associated β-galactosidase (SA-β-Gal) activity, cell size, telomere length and gene expression of MSCs cultured in vitro over 11 passages. This set of morphological, physiological and genetic senescence markers was correlated to the ability of MSCs to differentiate. Differentiation efficiency was assessed by marker genes and protein expression. CFUs decreased with increasing passage number, whereas SA-β-Gal activity and PDT increased; however, the correlation with MSCs' differentiation potential was sometimes unexpected. The expression of genes related to senescence was higher in late-passage cells than in early-passage cells. Early-passage cells underwent efficient osteogenic differentiation, with mid-passage cells performing best in chondrogenic differentiation. Late-passage cells preserve only adipogenic differentiation potential. Based on this marker set, we propose a senescence score in which combined markers give a reliable quality control of MSCs, not depending only on mechanistic passage number.
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Affiliation(s)
- Alessandro Bertolo
- Swiss Paraplegic Research, Nottwil, Switzerland.,Institute for Surgical Technology and Biomechanics, University of Bern, Switzerland
| | - Marco Mehr
- Swiss Paraplegic Research, Nottwil, Switzerland
| | | | | | - Niklaus Aebli
- Swiss Paraplegic Centre, Nottwil, Switzerland.,School of Medicine, Griffith University, Brisbane, Queensland, Australia
| | - Martin Baur
- Cantonal Hospital of Lucerne, Lucerne, Switzerland
| | | | - Jivko V Stoyanov
- Swiss Paraplegic Research, Nottwil, Switzerland.,Institute for Surgical Technology and Biomechanics, University of Bern, Switzerland
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Shalev I. Early life stress and telomere length: investigating the connection and possible mechanisms: a critical survey of the evidence base, research methodology and basic biology. Bioessays 2012; 34:943-52. [PMID: 22991129 PMCID: PMC3557830 DOI: 10.1002/bies.201200084] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
How can adverse experiences in early life, such as maltreatment, exert such powerful negative effects on health decades later? The answer may lie in changes to DNA. New research suggests that exposure to stress can accelerate the erosion of DNA segments called telomeres. Shorter telomere length correlates with chronological age and also disease morbidity and mortality. Thus, telomere erosion is a potential mechanism linking childhood stress to health problems later in life. However, an array of mechanistic, methodological, and basic biological questions must be addressed in order to translate telomere discoveries into clinical applications for monitoring health and predicting disease risk. This paper covers the current state of the science and lays out new research directions.
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Affiliation(s)
- Idan Shalev
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA.
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40
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Kelm JM, Emmert MY, Zürcher A, Schmidt D, Begus Nahrmann Y, Rudolph KL, Weber B, Brokopp CE, Frauenfelder T, Leschka S, Odermatt B, Jenni R, Falk V, Zünd G, Hoerstrup SP. Functionality, growth and accelerated aging of tissue engineered living autologous vascular grafts. Biomaterials 2012; 33:8277-85. [PMID: 22906604 DOI: 10.1016/j.biomaterials.2012.07.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/24/2012] [Indexed: 10/28/2022]
Abstract
Living autologous tissue engineered vascular-grafts (TEVGs) with growth-capacity may overcome the limitations of contemporary artificial-prostheses. However, the multi-step in vitro production of TEVGs requires extensive ex vivo cell-manipulations with unknown effects on functionality and quality of TEVGs due to an accelerated biological age of the cells. Here, the impact of biological cell-age and tissue-remodeling capacity of TEVGs in relation to their clinical long-term functionality are investigated. TEVGs were implanted as pulmonary-artery (PA) replacements in juvenile sheep and followed for up to 240 weeks (∼4.5years). Telomere length and telomerase activity were compared amongst TEVGs and adjacent native tissue. Telomerase-activity of in vitro expanded autologous vascular-cells prior to seeding was <5% as compared to a leukemic cell line, indicating biological-aging associated with decreasing telomere-length with each cellular-doubling. Up to 100 weeks, the cells in the TEVGs had consistently shorter telomeres compared to the native counterpart, whereas no significant differences were detectable at 240 weeks. Computed tomography (CT) analysis demonstrated physiological wall-pressures, shear-stresses, and flow-pattern comparable to the native PA. There were no signs of degeneration detectable and continuous native-analogous growth was confirmed by vessel-volumetry. TEVGs exhibit a higher biological age compared to their native counterparts. However, despite of this tissue engineering technology related accelerated biological-aging, growth-capacity and long-term functionality was not compromised. To the contrary, extensive in-vivo remodeling processes with substantial endogenous cellular turnover appears to result in "TEVG rejuvenation" and excellent clinical performance. As these large-animal results can be extrapolated to approximately 20 human years, this study suggests long-term clinical-safety of cardiovascular in vitro tissue engineering and may contribute to safety-criteria as to first-in-man clinical-trials.
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Affiliation(s)
- Jens M Kelm
- Swiss Centre for Regenerative Medicine, University Hospital and University of Zurich, Zurich, Switzerland
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Modulation of telomeres in alternative lengthening of telomeres type I like human cells by the expression of werner protein and telomerase. JOURNAL OF ONCOLOGY 2012; 2012:806382. [PMID: 22545052 PMCID: PMC3321466 DOI: 10.1155/2012/806382] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 12/13/2011] [Accepted: 01/10/2012] [Indexed: 02/06/2023]
Abstract
The alternative lengthening of telomeres (ALT) is a recombination-based mechanism of telomere maintenance activated in 5–20% of human cancers. In Saccharomyces cerevisiae, survivors that arise after inactivation of telomerase can be classified as type I or type II ALT. In type I, telomeres have a tandem array structure, with each subunit consisting of a subtelomeric Y′ element and short telomere sequence. Telomeres in type II have only long telomere repeats and require Sgs1, the S. cerevisiae RecQ family helicase. We previously described the first human ALT cell line, AG11395, that has a telomere structure similar to type I ALT yeast cells. This cell line lacks the activity of the Werner syndrome protein, a human RecQ helicase. The telomeres in this cell line consist of tandem repeats containing SV40 DNA, including the origin of replication, and telomere sequence. We investigated the role of the SV40 origin of replication and the effects of Werner protein and telomerase on telomere structure and maintenance in AG11395 cells. We report that the expression of Werner protein facilitates the transition in human cells of ALT type I like telomeres to type II like telomeres in some aspects. These findings have implications for the diagnosis and treatment of cancer.
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Min J, Choi ES, Hwang K, Kim J, Sampath S, Venkitaraman AR, Lee H. The breast cancer susceptibility gene BRCA2 is required for the maintenance of telomere homeostasis. J Biol Chem 2012; 287:5091-101. [PMID: 22187435 PMCID: PMC3281639 DOI: 10.1074/jbc.m111.278994] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Revised: 12/19/2011] [Indexed: 11/06/2022] Open
Abstract
Inactivating mutations in the breast cancer susceptibility gene BRCA2 cause gross chromosomal rearrangements. Chromosome structural instability in the absence of BRCA2 is thought to result from defective homology-directed DNA repair. Here, we show that BRCA2 links the fidelity of telomere maintenance with genetic integrity. Absence of BRCA2 resulted in signs of dysfunctional telomeres, such as telomere shortening, erosions, and end fusions in proliferating mouse fibroblasts. BRCA2 localized to the telomeres in S phase in an ATR-dependent manner, and its absence resulted in the accumulation of common fragile sites, particularly at the G-rich lagging strand, and increased the telomere sister chromatid exchange in unchallenged cells. The incidence of common fragile sites and telomere sister chromatid exchange increased markedly after treatment with replication inhibitors. Congruently, telomere-induced foci were frequently observed in the absence of Brca2, denoting activation of the DNA damage response and abnormal chromosome end joining. These telomere end fusions constituted a significant portion of chromosome aberrations in Brca2-deficient cells. Our results suggest that BRCA2 is required for telomere homeostasis and may be particularly important for the replication of G-rich telomeric lagging strands.
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Affiliation(s)
- Jaewon Min
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
| | - Eun Shik Choi
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
| | - Kwangwoo Hwang
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
| | - Jimi Kim
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
| | - Srihari Sampath
- the Medical Research Council Cancer Cell Unit, Hutchison/Medical Research Council Research Centre, University of Cambridge, Hills Road, Cambridge CB2 0XZ, United Kingdom
| | - Ashok R. Venkitaraman
- the Medical Research Council Cancer Cell Unit, Hutchison/Medical Research Council Research Centre, University of Cambridge, Hills Road, Cambridge CB2 0XZ, United Kingdom
| | - Hyunsook Lee
- From the Department of Biological Sciences and the Institute of Molecular Biology and Genetics, Seoul National University, 599 Gwanak-Ro, Gwanak-Gu, Seoul 151-742, Korea and
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Prolonged self-renewal activity unmasks telomerase control of telomere homeostasis and function of mouse hematopoietic stem cells. Blood 2011; 118:1766-73. [PMID: 21730353 DOI: 10.1182/blood-2010-11-319632] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Strategies for expanding hematopoietic stem cells (HSCs) could have significant utility for transplantation-based therapies. However, deleterious consequences of such manipulations remain unknown. Here we examined the impact of HSC self-renewal divisions in vitro and in vivo on their subsequent regenerative and continuing ability to sustain blood cell production in the absence of telomerase. HSC expansion in vitro was obtained using a NUP98-HOXA10hd transduction strategy and, in vivo, using a serial transplant protocol. We observed ~ 10kb telomere loss in leukocytes produced in secondary mice transplanted with HSCs regenerated in primary recipients of NUP98-HOXA10hd-transduced and in vitro-expanded Tert(-/-) HSCs 6 months before. The second generation leukocytes also showed elevated expression of γH2AX (relative to control) indicative of greater accumulating DNA damage. In contrast, significant telomere shortening was not detected in leukocytes produced from freshly isolated, serially transplanted wild-type (WT) or Tert(-/-) HSCs, suggesting that HSC replication posttransplant is not limited by telomere shortening in the mouse. These findings document a role of telomerase in telomere homeostasis, and in preserving HSC functional integrity on prolonged self-renewal stimulation.
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Strong MA, Vidal-Cardenas SL, Karim B, Yu H, Guo N, Greider CW. Phenotypes in mTERT⁺/⁻ and mTERT⁻/⁻ mice are due to short telomeres, not telomere-independent functions of telomerase reverse transcriptase. Mol Cell Biol 2011; 31:2369-79. [PMID: 21464209 PMCID: PMC3133422 DOI: 10.1128/mcb.05312-11] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 03/23/2011] [Indexed: 02/01/2023] Open
Abstract
Telomerase is essential for telomere length maintenance. Mutations in either of the two core components of telomerase, telomerase RNA (TR) or the catalytic protein component telomerase reverse transcriptase (TERT), cause the genetic disorders dyskeratosis congenita, pulmonary fibrosis, and other degenerative diseases. Overexpression of the TERT protein has been reported to have telomere length-independent roles, including regulation of the Wnt signaling pathway. To examine the phenotypes of TERT haploinsufficiency and determine whether loss of function of TERT has effects other than those associated with telomere shortening, we characterized both mTERT⁺/⁻ and mTERT⁻/⁻ mice on the CAST/EiJ genetic background. Phenotypic analysis showed a loss of tissue renewal capacity with progressive breeding of heterozygous mice that was indistinguishable from that of mTR-deficient mice. mTERT⁻/⁻ mice, from heterozygous mTERT⁺/⁻ mouse crosses, were born at the expected Mendelian ratio (26.5%; n = 1,080 pups), indicating no embryonic lethality of this genotype. We looked for, and failed to find, hallmarks of Wnt deficiency in various adult and embryonic tissues, including those of the lungs, kidneys, brain, and skeleton. Finally, mTERT⁻/⁻ cells showed wild-type levels of Wnt signaling in vitro. Thus, while TERT overexpression in some settings may activate the Wnt pathway, loss of function in a physiological setting has no apparent effects on Wnt signaling. Our results indicate that both TERT and TR are haploinsufficient and that their deficiency leads to telomere shortening, which limits tissue renewal. Our studies imply that hypomorphic loss-of-function alleles of hTERT and hTR should cause a similar disease spectrum in humans.
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Affiliation(s)
| | | | - Baktiar Karim
- Department of Molecular & Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Huimin Yu
- Department of Molecular Biology & Genetics
| | - Nini Guo
- Department of Molecular Biology & Genetics
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45
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Klewes L, Höbsch C, Katzir N, Rourke D, Garini Y, Mai S. Novel automated three-dimensional genome scanning based on the nuclear architecture of telomeres. Cytometry A 2010; 79:159-66. [PMID: 21265009 DOI: 10.1002/cyto.a.21012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 11/16/2010] [Accepted: 11/28/2010] [Indexed: 01/14/2023]
Abstract
Telomeres, the end of chromosomes, are organized in a nonoverlapping fashion and form microterritories in nuclei of normal cells. Previous studies have shown that normal and tumor cell nuclei differ in their 3D telomeric organization. The differences include a change in the spatial organization of the telomeres, in telomere numbers and sizes and in the presence of telomeric aggregates. Previous attempts to identify the above parameters of 3D telomere organization were semi-automated. Here we describe the automation of 3D scanning for telomere signatures in interphase nuclei based on three-dimensional fluorescent in situ hybridization (3D-FISH) and, for the first time, define its sensitivity in tumor cell detection. The data were acquired with a high-throughput scanning/acquisition system that allows to measure cells and acquire 3D images of nuclei at high resolution with 40 × or 60 × oil and at a speed of 10,000-15,000 cells h(-1) , depending on the cell density on the slides. The automated scanning, TeloScan, is suitable for large series of samples and sample sizes. We define the sensitivity of this automation for tumor cell detection. The data output includes 3D telomere positions, numbers of telomeric aggregates, telomere numbers, and telomere signal intensities. We were able to detect one aberrant cell in 1,000 normal cells. In conclusions, we are able to detect tumor cells based on 3D architectural profiles of the genome. This new tool could, in the future, assist in patient diagnosis, in the detection of minimal residual disease, in the analysis of treatment response and in treatment decisions.
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Affiliation(s)
- Ludger Klewes
- Department of Physiology, University of Manitoba, Winnipeg, Canada
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46
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Chromosomal instability and telomere lengths of each chromosomal arm measured by Q-FISH in human fibroblast strains prior to replicative senescence☆. Mech Ageing Dev 2010; 131:614-24. [DOI: 10.1016/j.mad.2010.08.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 08/11/2010] [Accepted: 08/25/2010] [Indexed: 11/17/2022]
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47
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Chromosome orientation fluorescence in situ hybridization to study sister chromatid segregation in vivo. Nat Protoc 2010; 5:1362-77. [PMID: 20595964 DOI: 10.1038/nprot.2010.102] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Previously, assays for sister chromatid segregation patterns relied on incorporation of 5-bromo-2'-deoxyuridine (BrdU) and indirect methods to infer segregation patterns after two cell divisions. In this study, we describe a method to differentially label sister chromatids of mouse cells and to directly assay sister chromatid segregation patterns after one cell division in vitro and in vivo by adaptation of the well-established CO-FISH technique. BrdU is incorporated into newly formed DNA strands, which are then subjected to photolysis and exonuclease digestion to create single-stranded sister chromatids containing parental template DNA only. Such single-stranded sister chromatids are differentially labeled using unidirectional probes to major satellite sequences coupled to fluorescent markers. Differentially labeled sister chromatids in postmitotic cells are visualized using fluorescence microscopy, and sister chromatid segregation patterns can be directly assayed after one cell division. This procedure requires 4 d for in vivo mouse tissues and 2 d for in vitro-cultured cells.
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48
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The Werner syndrome protein suppresses telomeric instability caused by chromium (VI) induced DNA replication stress. PLoS One 2010; 5:e11152. [PMID: 20585393 PMCID: PMC2886837 DOI: 10.1371/journal.pone.0011152] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 05/20/2010] [Indexed: 01/08/2023] Open
Abstract
Telomeres protect the chromosome ends and consist of guanine-rich repeats coated by specialized proteins. Critically short telomeres are associated with disease, aging and cancer. Defects in telomere replication can lead to telomere loss, which can be prevented by telomerase-mediated telomere elongation or activities of the Werner syndrome helicase/exonuclease protein (WRN). Both telomerase and WRN attenuate cytotoxicity induced by the environmental carcinogen hexavalent chromium (Cr(VI)), which promotes replication stress and DNA polymerase arrest. However, it is not known whether Cr(VI)-induced replication stress impacts telomere integrity. Here we report that Cr(VI) exposure of human fibroblasts induced telomeric damage as indicated by phosphorylated H2AX (γH2AX) at telomeric foci. The induced γH2AX foci occurred in S-phase cells, which is indicative of replication fork stalling or collapse. Telomere fluorescence in situ hybridization (FISH) of metaphase chromosomes revealed that Cr(VI) exposure induced an increase in telomere loss and sister chromatid fusions that were rescued by telomerase activity. Human cells depleted for WRN protein exhibited a delayed reduction in telomeric and non-telomeric damage, indicated by γH2AX foci, during recovery from Cr(VI) exposure, consistent with WRN roles in repairing damaged replication forks. Telomere FISH of chromosome spreads revealed that WRN protects against Cr(VI)-induced telomere loss and downstream chromosome fusions, but does not prevent chromosome fusions that retain telomere sequence at the fusion point. Our studies indicate that environmentally induced replication stress leads to telomere loss and aberrations that are suppressed by telomerase-mediated telomere elongation or WRN functions in replication fork restoration.
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Sarthy J, Bae NS, Scrafford J, Baumann P. Human RAP1 inhibits non-homologous end joining at telomeres. EMBO J 2009; 28:3390-9. [PMID: 19763083 DOI: 10.1038/emboj.2009.275] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 08/25/2009] [Indexed: 12/22/2022] Open
Abstract
Telomeres, the nucleoprotein structures at the ends of linear chromosomes, promote genome stability by distinguishing chromosome termini from DNA double-strand breaks (DSBs). Cells possess two principal pathways for DSB repair: homologous recombination and non-homologous end joining (NHEJ). Several studies have implicated TRF2 in the protection of telomeres from NHEJ, but the underlying mechanism remains poorly understood. Here, we show that TRF2 inhibits NHEJ, in part, by recruiting human RAP1 to telomeres. Heterologous targeting of hRAP1 to telomeric DNA was sufficient to bypass the need for TRF2 in protecting telomeric DNA from NHEJ in vitro. On expanding these studies in cells, we find that recruitment of hRAP1 to telomeres prevents chromosome fusions caused by the loss of TRF2/hRAP1 from chromosome ends despite activation of a DNA damage response. These results provide the first evidence that hRAP1 inhibits NHEJ at mammalian telomeres and identify hRAP1 as a mediator of genome stability.
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Affiliation(s)
- Jay Sarthy
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
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Abstract
In this study, we examine the telomeric functions of the mammalian Mre11 complex by using hypomorphic Mre11 and Nbs1 mutants (Mre11(ATLD1/ATLD1) and Nbs1(Delta)(B/)(DeltaB), respectively). No telomere shortening was observed in Mre11(ATLD1/ATLD1) cells after extensive passage through culture, and the rate of telomere shortening in telomerase-deficient (Tert(Delta)(/)(Delta)) Mre11(ATLD1/ATLD1) cells was the same as that in Tert(Delta)(/)(Delta) alone. Although telomeres from late-passage Mre11(ATLD1/ATLD1) Tert(Delta)(/)(Delta) cells were as short as those from Tert(Delta)(/)(Delta), the incidence of telomere fusions was reduced. This effect on fusions was also evident upon acute telomere dysfunction in Mre11(ATLD1/ATLD1) and Nbs1(Delta)(B/)(DeltaB) cells rendered Trf2 deficient by cre-mediated TRF2 inactivation than in wild-type cells. The residual fusions formed in Mre11 complex mutant cells exhibited a strong tendency toward chromatid fusions, with an almost complete bias for fusion of telomeres replicated by the leading strand. Finally, the response to acute telomere dysfunction was strongly impaired by Mre11 complex hypomorphism, as the formation of telomere dysfunction-induced DNA damage foci was reduced in both cre-infected Mre11(ATLD1/ATLD1) Trf2(F/)(Delta) and Nbs1(Delta)(B/)(DeltaB) Trf2(F/F) cells. These data indicate that the Mre11 complex influences the cellular response to telomere dysfunction, reminiscent of its influence on the response to interstitial DNA breaks, and suggest that it may promote telomeric DNA end processing during DNA replication.
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