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O'Daniel SE, Kochan KJ, Long CR, Riley DG, Randel RD, Welsh TH. Comparison of Telomere Length in Age-Matched Primiparous and Multiparous Brahman Cows. Animals (Basel) 2023; 13:2325. [PMID: 37508101 PMCID: PMC10376255 DOI: 10.3390/ani13142325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
Physiological and psychological stressors have been associated with the attrition of telomeres, which are the protective caps of chromosomes. This study compares the telomere length (TL) in 4-year-old Brahman cows grouped by the first parity (n = 8) and the second parity (n = 11). The cows were bled via jugular venipuncture, weighed, and had their body condition scores recorded at Day -28 prior to calving and at Day + 7 and Day + 28 post-calving. The duration of labor (Dlabor) and parturition ease were recorded. The peripheral leukocytes were isolated, the leukocyte blood count with differential was recorded, and the genomic DNA was extracted. The relative quantity of telomere products, which is proportional to the average TL, was determined via multiplex quantitative PCR using the ratio (T/S ratio) of bovine telomere and β-globulin DNA. Standards of the bovine telomere (1012-107 dilution series) and β-globulin (109-104 dilution series) genes were utilized to produce relative copy numbers. The samples were assayed in triplicate and were included if the triplicate Cq difference was less than 0.25 cycles. The parity was the fixed effect, and the random effects included the sire and day repeated with the cow as the subject. Statistical significance was not observed in the leukocyte number or type (p > 0.1). A reduction in the TL of approximately 9225 telomeric copies was found between Parity 1 and Parity 2 (p = 0.02). A trend was found between the TL and Dlabor (p = 0.06). The stress of parturition and raising the first calf of a cow's life may be responsible for TL attenuation. Parity may be considered a stressor of cow longevity.
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Affiliation(s)
- Sydney E O'Daniel
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
- Texas A&M AgriLife Research Center, Overton, TX 75684, USA
| | - Kelli J Kochan
- Texas A&M Institute for Genome Sciences and Society, Texas A&M University, College Station, TX 77843, USA
| | - Charles R Long
- Texas A&M AgriLife Research Center, Overton, TX 75684, USA
| | - David G Riley
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
| | | | - Thomas H Welsh
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
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Abstract
The number of (TTAGGG)n repeats at the ends of chromosomes is highly variable between individual chromosomes, between different cells and between species. Progressive loss of telomere repeats limits the proliferation of pre-malignant human cells but also contributes to aging by inducing apoptosis and senescence in normal cells. Despite enormous progress in understanding distinct pathways that result in loss and gain of telomeric DNA in different cell types, many questions remain. Further studies are needed to delineate the role of damage to telomeric DNA, replication errors, chromatin structure, liquid-liquid phase transition, telomeric transcripts (TERRA) and secondary DNA structures such as guanine quadruplex structures, R-loops and T-loops in inducing gains and losses of telomere repeats in different cell types. Limitations of current telomere length measurements techniques and differences in telomere biology between species and different cell types complicate generalizations about the role of telomeres in aging and cancer. Here some of the factors regulating the telomere length in embryonic and adult cells in mammals are discussed from a mechanistic and evolutionary perspective.
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Affiliation(s)
- Peter Lansdorp
- Terry Fox Laboratory, British Columbia (BC) Cancer Agency, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Peter Lansdorp,
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3
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Nutrition Interventions of Herbal Compounds on Cellular Senescence. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:1059257. [PMID: 35528514 PMCID: PMC9068308 DOI: 10.1155/2022/1059257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 11/01/2021] [Accepted: 04/02/2022] [Indexed: 01/10/2023]
Abstract
When cells undergo large-scale senescence, organ aging ensues, resulting in irreversible organ pathology and organismal aging. The study of senescence in cells provides an important avenue to understand the factors that influence aging and can be used as one of the useful tools for examining age-related human diseases. At present, many herbal compounds have shown effects on delaying cell senescence. This review summarizes the main characteristics and mechanisms of cell senescence, age-related diseases, and the recent progress on the natural products targeting cellular senescence, with the aim of providing insights to aid the clinical management of age-related diseases.
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Tarazón E, Pérez-Carrillo L, Giménez-Escamilla I, Ramos-Castellanos P, Martínez-Dolz L, Portolés M, Roselló-Lletí E. Relationships of Telomere Homeostasis with Oxidative Stress and Cardiac Dysfunction in Human Ischaemic Hearts. Antioxidants (Basel) 2021; 10:antiox10111750. [PMID: 34829621 PMCID: PMC8615212 DOI: 10.3390/antiox10111750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 12/24/2022] Open
Abstract
Although the roles of telomeres and oxidative stress in ischaemic cardiomyopathy (ICM) are known, mechanisms of telomere homeostasis and their relationship with oxidative stress are incompletely understood. We performed two RNA-seq analyses (mRNA n = 23; ncRNA n = 30) and protein validation on left ventricles of explanted hearts from ICM and control subjects. We observed dysregulation of the shelterin and cohesin complexes, which was related to an increase in the response to cellular oxidative stress. Moreover, we found alterations at mRNA level in the mechanisms of telomeric DNA repair. Specifically, increased RAD51D mRNA levels were correlated with left ventricular diameters. RAD51D protein levels were unaltered, however, and were inversely corelated with the miR-103a-3p upregulation. We also observed the overexpression of lncRNAs (TERRA and GUARDIN) involved in telomere protection in response to stress and alterations in their regulatory molecules. Expression of the TERRA transcription factor ATF7 was correlated with superoxide dismutase 1 expression and left ventricular diameters. The levels of GUARDIN and its transcription factor FOSL2 were correlated with those of catalase. Therefore, we showed specific alterations in the mechanisms of telomeric DNA repair and protection, and these alterations are related to an increase in the response mechanisms to oxidative stress and cardiac dysfunction in ICM.
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Affiliation(s)
- Estefanía Tarazón
- Myocardial Dysfunction and Cardiac Transplantation Unit, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain; (L.P.-C.); (I.G.-E.); (P.R.-C.); (L.M.-D.); (M.P.)
- CIBERCV, Institute of Health Carlos III, C/Monforte de Lemos 3–5, Pabellón 11, Planta 0, 28029 Madrid, Spain
- Correspondence: (E.T.); (E.R.-L.); Tel.: +34-96-124-66-44 (E.T. & E.R.-L.)
| | - Lorena Pérez-Carrillo
- Myocardial Dysfunction and Cardiac Transplantation Unit, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain; (L.P.-C.); (I.G.-E.); (P.R.-C.); (L.M.-D.); (M.P.)
| | - Isaac Giménez-Escamilla
- Myocardial Dysfunction and Cardiac Transplantation Unit, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain; (L.P.-C.); (I.G.-E.); (P.R.-C.); (L.M.-D.); (M.P.)
| | - Pablo Ramos-Castellanos
- Myocardial Dysfunction and Cardiac Transplantation Unit, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain; (L.P.-C.); (I.G.-E.); (P.R.-C.); (L.M.-D.); (M.P.)
| | - Luis Martínez-Dolz
- Myocardial Dysfunction and Cardiac Transplantation Unit, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain; (L.P.-C.); (I.G.-E.); (P.R.-C.); (L.M.-D.); (M.P.)
- CIBERCV, Institute of Health Carlos III, C/Monforte de Lemos 3–5, Pabellón 11, Planta 0, 28029 Madrid, Spain
- Heart Failure and Transplantation Unit, Cardiology Department, University and Polytechnic La Fe Hospital, 46026 Valencia, Spain
| | - Manuel Portolés
- Myocardial Dysfunction and Cardiac Transplantation Unit, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain; (L.P.-C.); (I.G.-E.); (P.R.-C.); (L.M.-D.); (M.P.)
- CIBERCV, Institute of Health Carlos III, C/Monforte de Lemos 3–5, Pabellón 11, Planta 0, 28029 Madrid, Spain
| | - Esther Roselló-Lletí
- Myocardial Dysfunction and Cardiac Transplantation Unit, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain; (L.P.-C.); (I.G.-E.); (P.R.-C.); (L.M.-D.); (M.P.)
- CIBERCV, Institute of Health Carlos III, C/Monforte de Lemos 3–5, Pabellón 11, Planta 0, 28029 Madrid, Spain
- Correspondence: (E.T.); (E.R.-L.); Tel.: +34-96-124-66-44 (E.T. & E.R.-L.)
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Ebeid DE, Khalafalla FG, Broughton KM, Monsanto MM, Esquer CY, Sacchi V, Hariharan N, Korski KI, Moshref M, Emathinger J, Cottage CT, Quijada PJ, Nguyen JH, Alvarez R, Völkers M, Konstandin MH, Wang BJ, Firouzi F, Navarrete JM, Gude NA, Goumans MJ, Sussman MA. Pim1 maintains telomere length in mouse cardiomyocytes by inhibiting TGFβ signalling. Cardiovasc Res 2021; 117:201-211. [PMID: 32176281 PMCID: PMC7797214 DOI: 10.1093/cvr/cvaa066] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 03/13/2019] [Indexed: 12/26/2022] Open
Abstract
AIMS Telomere attrition in cardiomyocytes is associated with decreased contractility, cellular senescence, and up-regulation of proapoptotic transcription factors. Pim1 is a cardioprotective kinase that antagonizes the aging phenotype of cardiomyocytes and delays cellular senescence by maintaining telomere length, but the mechanism remains unknown. Another pathway responsible for regulating telomere length is the transforming growth factor beta (TGFβ) signalling pathway where inhibiting TGFβ signalling maintains telomere length. The relationship between Pim1 and TGFβ has not been explored. This study delineates the mechanism of telomere length regulation by the interplay between Pim1 and components of TGFβ signalling pathways in proliferating A549 cells and post-mitotic cardiomyocytes. METHODS AND RESULTS Telomere length was maintained by lentiviral-mediated overexpression of PIM1 and inhibition of TGFβ signalling in A549 cells. Telomere length maintenance was further demonstrated in isolated cardiomyocytes from mice with cardiac-specific overexpression of PIM1 and by pharmacological inhibition of TGFβ signalling. Mechanistically, Pim1 inhibited phosphorylation of Smad2, preventing its translocation into the nucleus and repressing expression of TGFβ pathway genes. CONCLUSION Pim1 maintains telomere lengths in cardiomyocytes by inhibiting phosphorylation of the TGFβ pathway downstream effectors Smad2 and Smad3, which prevents repression of telomerase reverse transcriptase. Findings from this study demonstrate a novel mechanism of telomere length maintenance and provide a potential target for preserving cardiac function.
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Affiliation(s)
- David E Ebeid
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Farid G Khalafalla
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Kathleen M Broughton
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Megan M Monsanto
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Carolina Y Esquer
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Veronica Sacchi
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Nirmala Hariharan
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Kelli I Korski
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Maryam Moshref
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Jacqueline Emathinger
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Christopher T Cottage
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Pearl J Quijada
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Jonathan H Nguyen
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Roberto Alvarez
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Mirko Völkers
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Mathias H Konstandin
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Bingyan J Wang
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Fareheh Firouzi
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Julian M Navarrete
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Natalie A Gude
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Marie-Jose Goumans
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Mark A Sussman
- Department of Biology, San Diego State University, North Life Sciences, 426, 5500 Campanile Drive, San Diego, CA 92182, USA
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Three-Dimensional Nuclear Telomere Profiling as a Biomarker for Recurrence in Oligodendrogliomas: A Pilot Study. Int J Mol Sci 2020; 21:ijms21228539. [PMID: 33198352 PMCID: PMC7696868 DOI: 10.3390/ijms21228539] [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: 08/11/2020] [Revised: 10/27/2020] [Accepted: 11/04/2020] [Indexed: 12/24/2022] Open
Abstract
Mechanisms of recurrence in oligodendrogliomas are poorly understood. Recurrence might be driven by telomere dysfunction-mediated genomic instability. In a pilot study, we investigated ten patients with oligodendrogliomas at the time of diagnosis (first surgery) and after recurrence (second surgery) using three-dimensional nuclear telomere analysis performed with quantitative software TeloView® (Telo Genomics Corp, Toronto, Ontario, Canada). 1p/19q deletion status of each patient was determined by fluorescent in situ hybridization on touch preparation slides. We found that a very specific 3D telomeric profile was associated with two pathways of recurrence in oligodendrogliomas independent of their 1p/19q status: a first group of 8 patients displayed significantly different 3D telomere profiles between both surgeries (p < 0.0001). Their recurrence happened at a mean of 231.375 ± 117.42 days and a median time to progression (TTP) of 239 days, a period defined as short-term recurrence; and a second group of three patients displayed identical 3D telomere profiles between both surgery samples (p > 0.05). Their recurrence happened at a mean of 960.666 ± 86.19 days and a median TTP of 930 days, a period defined as long-term recurrence. Our results suggest a potential link between nuclear telomere architecture and telomere dysfunction with time to recurrence in oligodendrogliomas, independently of the 1p/19q status.
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Olsson M, Geraghty NJ, Wapstra E, Wilson M. Telomere length varies substantially between blood cell types in a reptile. ROYAL SOCIETY OPEN SCIENCE 2020; 7:192136. [PMID: 32742684 PMCID: PMC7353983 DOI: 10.1098/rsos.192136] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/12/2020] [Indexed: 05/19/2023]
Abstract
Telomeres are repeat sequences of non-coding DNA-protein molecules that cap or intersperse metazoan chromosomes. Interest in telomeres has increased exponentially in recent years, to now include their ongoing dynamics and evolution within natural populations where individuals vary in telomere attributes. Phylogenetic analyses show profound differences in telomere length across non-model taxa. However, telomeres may also differ in length within individuals and between tissues. The latter becomes a potential source of error when researchers use different tissues for extracting DNA for telomere analysis and scientific inference. A commonly used tissue type for assessing telomere length is blood, a tissue that itself varies in terms of nuclear content among taxa, in particular to what degree their thrombocytes and red blood cells (RBCs) contain nuclei or not. Specifically, when RBCs lack nuclei, leucocytes become the main source of telomeric DNA. RBCs and leucocytes differ in lifespan and how long they have been exposed to 'senescence' and erosion effects. We report on a study in which cells in whole blood from individual Australian painted dragon lizards (Ctenophorus pictus) were identified using flow cytometry and their telomere length simultaneously measured. Lymphocyte telomeres were on average 270% longer than RBC telomeres, and in azurophils (a reptilian monocyte), telomeres were more than 388% longer than those in RBCs. If this variation in telomere length among different blood cell types is a widespread phenomenon, and DNA for comparative telomere analyses are sourced from whole blood, evolutionary inference of telomere traits among taxa may be seriously complicated by the blood cell type comprising the main source of DNA.
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Affiliation(s)
- Mats Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- The School of Earth, Atmospheric and Life Sciences, University of Wollongong, Australia
- Author for correspondence: Mats Olsson e-mail:
| | - Nicholas J. Geraghty
- The School of Earth, Atmospheric and Life Sciences, University of Wollongong, Australia
| | - Erik Wapstra
- School of Natural Sciences, University of Tasmania, Hobart, Australia
| | - Mark Wilson
- School of Chemistry and Molecular Bioscience, Illawarra Health and Medical Research Institute, University of Wollongong, Australia
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Molecular Biology of Basal and Squamous Cell Carcinomas. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1268:171-191. [PMID: 32918219 DOI: 10.1007/978-3-030-46227-7_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The prevalent keratinocyte-derived neoplasms of the skin are basal cell carcinoma and squamous cell carcinoma. Both so-called non-melanoma skin cancers comprise the most common cancers in humans by far. Common risk factors for both tumor entities include sun exposure, DNA repair deficiencies leading to chromosomal instability, or immunosuppression. Yet, fundamental differences in the development of the two different entities have been and are currently unveiled. The constitutive activation of the sonic hedgehog signaling pathway by acquired mutations in the PTCH and SMO genes appears to represent the early basal cell carcinoma developmental determinant. Although other signaling pathways are also affected, small hedgehog inhibitory molecules evolve as the most promising basal cell carcinoma treatment options systemically as well as topically in current clinical trials. For squamous cell carcinoma development, mutations in the p53 gene, especially UV-induced mutations, have been identified as early events. Yet, other signaling pathways including epidermal growth factor receptor, RAS, Fyn, or p16INK4a signaling may play significant roles in squamous cell carcinoma development. The improved understanding of the molecular events leading to different tumor entities by de-differentiation of the same cell type has begun to pave the way for modulating new molecular targets therapeutically with small molecules.
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Louzon M, Coeurdassier M, Gimbert F, Pauget B, de Vaufleury A. Telomere dynamic in humans and animals: Review and perspectives in environmental toxicology. ENVIRONMENT INTERNATIONAL 2019; 131:105025. [PMID: 31352262 DOI: 10.1016/j.envint.2019.105025] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 06/19/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
Telomeres (TLs) play major roles in stabilizing the genome and are usually shortened with ageing. The maintenance of TLs is ensured by two mechanisms involving telomerase (TA) enzyme and alternative lengthening telomeres (ALT). TL shortening and/or TA inhibition have been related to health effects on organisms (leading to reduced reproductive lifespan and survival), suggesting that they could be key processes in toxicity mechanisms (at molecular and cellular levels) and relevant as an early warning of exposure and effect of chemicals on human health and animal population dynamics. Consequently, a critical analysis of knowledge about relationships between TL dynamic and environmental pollution is essential to highlight the relevance of TL measurement in environmental toxicology. The first objective of this review is to provide a survey on the basic knowledge about TL structure, roles, maintenance mechanisms and causes of shortening in both vertebrates (including humans) and invertebrates. Overall, TL length decreases with ageing but some unexpected exceptions are reported (e.g., in species with different lifespans, such as the nematode Caenorhabditis elegans or the crustacean Homarus americanus). Inconsistent results reported in various biological groups or even between species of the same genus (e.g., the microcrustacean Daphnia sp.) indicate that the relation usually proposed between TL shortening and a decrease in TA activity cannot be generalized and depends on the species, stage of development or lifespan. Although the scientific literature provides evidence of the effect of ageing on TL shortening, much less information on the relationships between shortening, maintenance of TLs, influence of other endogenous and environmental drivers, including exposure to chemical pollutants, is available, especially in invertebrates. The second objective of this review is to connect knowledge on TL dynamic and exposure to contaminants. Most of the studies published on humans rely on correlative epidemiological approaches and few in vitro experiments. They have shown TL attrition when exposed to contaminants, such as polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), pesticides and metallic elements (ME). In other vertebrates, the studies we found deals mainly with birds and, overall, report a disturbance of TL dynamic consecutively to exposure to chemicals, including metals and organic compounds. In invertebrates, no data are available and the potential of TL dynamic in environmental risk assessment remains to be explored. On the basis of the main gaps identified some research perspectives (e.g., impact of endogenous and environmental drivers, dose response effects, link between TL length, TA activity, longevity and ageing) are proposed to better understand the potential of TL and TA measurements in humans and animals in environmental toxicology.
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Affiliation(s)
- Maxime Louzon
- Department Chrono-Environnement, UMR UFC/CNRS 6249 USC INRA University of Bourgogne Franche-Comté, 16 route de Gray, 25000 Besançon, France
| | - Michael Coeurdassier
- Department Chrono-Environnement, UMR UFC/CNRS 6249 USC INRA University of Bourgogne Franche-Comté, 16 route de Gray, 25000 Besançon, France
| | - Frédéric Gimbert
- Department Chrono-Environnement, UMR UFC/CNRS 6249 USC INRA University of Bourgogne Franche-Comté, 16 route de Gray, 25000 Besançon, France
| | - Benjamin Pauget
- TESORA, Le Visium, 22 avenue Aristide Briand, 94110 Arcueil, France
| | - Annette de Vaufleury
- Department Chrono-Environnement, UMR UFC/CNRS 6249 USC INRA University of Bourgogne Franche-Comté, 16 route de Gray, 25000 Besançon, France.
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10
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Mosquera A, Rego-Pérez I, Blanco FJ, Fernández JL. Leukocyte Telomere Length in Patients with Radiographic Knee Osteoarthritis. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:298-301. [PMID: 30488497 DOI: 10.1002/em.22247] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/14/2018] [Accepted: 08/22/2018] [Indexed: 06/09/2023]
Abstract
Relative mean telomere sequence amount was determined by quantitative PCR (qPCR) of peripheral blood leukocyte (PBL) samples obtained at recruitment (n = 310) from individuals from the Osteoarthritis (OA) Initiative consortium. Knees were radiologically evaluated according to the Kellgren-Lawrence (KL) score, ranging from 0 to 4, considering a KL grade ≥ 2 as radiographic evidence of OA (n = 124). Telomere size decreased as baseline KL score increased, being significantly shorter in subjects with KL ≥2 (Mann-Whitney U-test, P < 0.0001). PBL telomere size was also associated with age, hypertension, body mass index (BMI) and waist circumference. Nevertheless, logistic regression analysis showed that PBL telomere size was a consistent risk factor for concurrent knee OA, independent of these health parameters. Shorter PBL telomeres may indicate a premature aging status which enhances chondrocyte senescence and degenerative joint disease. Environ. Mol. Mutagen. 60:298-301, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Alejandro Mosquera
- INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), Genetics Unit, A Coruña, Spain
| | - Ignacio Rego-Pérez
- INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), Rheumatology Division, A Coruña, Spain
| | - Francisco J Blanco
- INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), Rheumatology Division, A Coruña, Spain
| | - José Luis Fernández
- INIBIC-Complexo Hospitalario Universitario A Coruña (CHUAC), Genetics Unit, A Coruña, Spain
- Laboratory of Genetics and Radiobiology, Centro Oncologico de Galicia, A Coruña, Spain
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11
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Nanoparticle based simple electrochemical biosensor platform for profiling of protein-nucleic acid interactions. Talanta 2019; 195:46-54. [DOI: 10.1016/j.talanta.2018.11.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/02/2018] [Accepted: 11/05/2018] [Indexed: 12/24/2022]
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12
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Taking the Tube: From Normal Fallopian Tube Epithelium to Ovarian High-grade Serous Carcinoma. Clin Obstet Gynecol 2018; 60:697-710. [PMID: 29045296 DOI: 10.1097/grf.0000000000000313] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Detailed pathologic studies over the past decade suggest a distal fallopian tube origin for the majority of "ovarian" high-grade serous carcinomas (HGSC). This review will summarize molecular alterations observed in tubal precursors for HGSC, namely p53 signatures and serous tubal intraepithelial carcinomas, and in nonmalignant fallopian tube epithelial cells obtained from women at increased genetic risk for HGSC. Recent experiments investigating the impact of follicular fluid exposure and retrograde menstruation on tumor development in the fallopian tube will also be discussed. These data will be reconciled with traditional ovarian cancer risk factors related to reproductive history.
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Poudel L, Steinmetz NF, French RH, Parsegian VA, Podgornik R, Ching WY. Implication of the solvent effect, metal ions and topology in the electronic structure and hydrogen bonding of human telomeric G-quadruplex DNA. Phys Chem Chem Phys 2018; 18:21573-85. [PMID: 27425864 DOI: 10.1039/c6cp04357g] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We present a first-principles density functional study elucidating the effects of solvent, metal ions and topology on the electronic structure and hydrogen bonding of 12 well-designed three dimensional G-quadruplex (G4-DNA) models in different environments. Our study shows that the parallel strand structures are more stable in dry environments and aqueous solutions containing K(+) ions within the tetrad of guanine but conversely, that the anti-parallel structure is more stable in solutions containing the Na(+) ions within the tetrad of guanine. The presence of metal ions within the tetrad of the guanine channel always enhances the stability of the G4-DNA models. The parallel strand structures have larger HOMO-LUMO gaps than antiparallel structures, which are in the range of 0.98 eV to 3.11 eV. Partial charge calculations show that sugar and alkali ions are positively charged whereas nucleobases, PO4 groups and water molecules are all negatively charged. Partial charges on each functional group with different signs and magnitudes contribute differently to the electrostatic interactions involving G4-DNA and favor the parallel structure. A comparative study between specific pairs of different G4-DNA models shows that the Hoogsteen OH and NH hydrogen bonds in the guanine tetrad are significantly influenced by the presence of metal ions and water molecules, collectively affecting the structure and the stability of G4-DNA.
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Affiliation(s)
- Lokendra Poudel
- Department of Physics and Astronomy, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
| | - Nicole F Steinmetz
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA and Department of Radiology, Case Western Reserve University, Cleveland, OH 44106, USA and Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA and Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Roger H French
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA and Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA and Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA and Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - V Adrian Parsegian
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Rudolf Podgornik
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA and Department of Theoretical Physics, J. Stefan Institute, SI-1000 Ljubljana, Slovenia and Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Wai-Yim Ching
- Department of Physics and Astronomy, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
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14
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Angelier F, Costantini D, Blévin P, Chastel O. Do glucocorticoids mediate the link between environmental conditions and telomere dynamics in wild vertebrates? A review. Gen Comp Endocrinol 2018; 256:99-111. [PMID: 28705731 DOI: 10.1016/j.ygcen.2017.07.007] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/06/2017] [Accepted: 07/06/2017] [Indexed: 12/17/2022]
Abstract
Following the discoveries of telomeres and of their implications in terms of health and ageing, there has been a growing interest into the study of telomere dynamics in wild vertebrates. Telomeres are repeated sequences of non-coding DNA located at the terminal ends of chromosomes and they play a major role in maintaining chromosome stability. Importantly, telomeres shorten over time and shorter telomeres seem to be related with lower survival in vertebrates. Because of this potential link with longevity, it is crucial to understand not only the ecological determinants of telomere dynamics but also the regulatory endocrine mechanisms that may mediate the effect of the environment on telomeres. In this paper, we review the relationships that link environmental conditions, glucocorticoids (GC, the main hormonal mediator of allostasis) and telomere length in vertebrates. First, we review current knowledge about the determinants of inter-individual variations in telomere length. We emphasize the potential strong impact of environmental stressors and predictable life-history events on telomere dynamics. Despite recent progress, we still lack crucial basic data to fully understand the costs of several life-history stages and biotic and abiotic factors on telomere length. Second, we review the link that exists between GCs, oxidative stress and telomere dynamics in vertebrates. Although circulating GC levels may be closely and functionally linked with telomere dynamics, data are still scarce and somewhat contradictory. Further laboratory and field studies are therefore needed not only to better assess the proximate link between GC levels and telomere dynamics, but also to ultimately understand to what extent GCs and telomere length could be informative to measure the fitness costs of specific life-history stages and environmental conditions. Finally, we highlight the importance of exploring the functional links that may exist between coping styles, the GC stress response, and telomere dynamics in a life-history framework. To conclude, we raise new hypotheses regarding the potential of the GC stress response to drive the trade-off between immediate survival and telomere protection.
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Affiliation(s)
- Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, CNRS-ULR, UMR 7372, Villiers en Bois, France.
| | - David Costantini
- Muséum National d'Histoire Naturelle, UMR 7221, Paris, France; Behavioural Ecology & Ecophysiology Group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Pierre Blévin
- Centre d'Etudes Biologiques de Chizé, CNRS-ULR, UMR 7372, Villiers en Bois, France
| | - Olivier Chastel
- Centre d'Etudes Biologiques de Chizé, CNRS-ULR, UMR 7372, Villiers en Bois, France
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15
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Olsson M, Wapstra E, Friesen CR. Evolutionary ecology of telomeres: a review. Ann N Y Acad Sci 2017; 1422:5-28. [DOI: 10.1111/nyas.13443] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 06/30/2017] [Accepted: 07/06/2017] [Indexed: 12/26/2022]
Affiliation(s)
- Mats Olsson
- Department of Biological and Environmental Sciences University of Gothenburg Gothenburg Sweden
- School of Biological Sciences The University of Wollongong Wollongong New South Wales Australia
| | - Erik Wapstra
- School of Biological Sciences University of Tasmania Hobart Tasmania Australia
| | - Christopher R. Friesen
- School of Life and Environmental Sciences University of Sydney Sydney New South Wales Australia
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16
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The Relationship Between DOT1L, Histone H3 Methylation, and Genome Stability in Cancer. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/s40610-017-0051-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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17
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Nurkovic J, Volarevic V, Lako M, Armstrong L, Arsenijevic N, Stojkovic M. Aging of Stem and Progenitor Cells: Mechanisms, Impact on Therapeutic Potential, and Rejuvenation. Rejuvenation Res 2016; 19:3-12. [PMID: 26055182 DOI: 10.1089/rej.2015.1676] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
It was once suggested that adult or tissue-specific stem cells may be immortal; however, several recently published data suggest that their efficacy is limited by natural aging in common with most other somatic cell types. Decreased activity of stem cells in old age raises questions as to whether the age of the donor should be considered during stem cell transplantation and at what age the donor stem cells should be harvested to ensure the largest possible number of viable, functional, and non-altered stem cells. Although stem cells remain active into old age, changes in stem cells and their microenvironments inhibit their regenerative potential. The impact of aging on stem cell populations differs between tissues and depends on a number intrinsic and extrinsic factors, including systemic changes associated with immune system alterations. In this review, we describe key mechanisms of stem and progenitor cell aging and techniques that are currently used to identify signs of stem cells aging. Furthermore, we focus on the impact of aging on the capacity for proliferation, differentiation, and clinical use of stem cells. Finally, we detail the aging of embryonic, mesenchymal, and induced pluripotent stem cells, with particular emphasis on aging mechanisms and rejuvenation.
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Affiliation(s)
- Jasmin Nurkovic
- 1 Stem Cell Laboratory, Department of Biomedical Sciences, State University of Novi Pazar , Novi Pazar, Serbia
| | - Vladislav Volarevic
- 2 Centre for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac , Kragujevac, Serbia
| | - Majlinda Lako
- 3 Institute of Genetic Medicine, International Centre for Life, Newcastle University , Newcastle upon Tyne, United Kingdom
| | - Lyle Armstrong
- 3 Institute of Genetic Medicine, International Centre for Life, Newcastle University , Newcastle upon Tyne, United Kingdom
| | - Nebojsa Arsenijevic
- 2 Centre for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac , Kragujevac, Serbia
| | - Miodrag Stojkovic
- 2 Centre for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac , Kragujevac, Serbia .,4 Spebo Medical , Leskovac, Serbia
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18
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Transcription Regulation of the Human Telomerase Reverse Transcriptase (hTERT) Gene. Genes (Basel) 2016; 7:genes7080050. [PMID: 27548225 PMCID: PMC4999838 DOI: 10.3390/genes7080050] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/23/2016] [Accepted: 08/01/2016] [Indexed: 12/11/2022] Open
Abstract
Embryonic stem cells and induced pluripotent stem cells have the ability to maintain their telomere length via expression of an enzymatic complex called telomerase. Similarly, more than 85%–90% of cancer cells are found to upregulate the expression of telomerase, conferring them with the potential to proliferate indefinitely. Telomerase Reverse Transcriptase (TERT), the catalytic subunit of telomerase holoenzyme, is the rate-limiting factor in reconstituting telomerase activity in vivo. To date, the expression and function of the human Telomerase Reverse Transcriptase (hTERT) gene are known to be regulated at various molecular levels (including genetic, mRNA, protein and subcellular localization) by a number of diverse factors. Among these means of regulation, transcription modulation is the most important, as evident in its tight regulation in cancer cell survival as well as pluripotent stem cell maintenance and differentiation. Here, we discuss how hTERT gene transcription is regulated, mainly focusing on the contribution of trans-acting factors such as transcription factors and epigenetic modifiers, as well as genetic alterations in hTERT proximal promoter.
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19
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Liu CC, Ma DL, Yan TD, Fan X, Poon Z, Poon LF, Goh SA, Rozen SG, Hwang WYK, Tergaonkar V, Tan P, Ghosh S, Virshup DM, Goh ELK, Li S. Distinct Responses of Stem Cells to Telomere Uncapping-A Potential Strategy to Improve the Safety of Cell Therapy. Stem Cells 2016; 34:2471-2484. [PMID: 27299710 DOI: 10.1002/stem.2431] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 04/18/2016] [Accepted: 05/14/2016] [Indexed: 12/29/2022]
Abstract
In most human somatic cells, the lack of telomerase activity results in progressive telomere shortening during each cell division. Eventually, DNA damage responses triggered by critically short telomeres induce an irreversible cell cycle arrest termed replicative senescence. However, the cellular responses of human pluripotent stem cells to telomere uncapping remain unknown. We generated telomerase knockout human embryonic stem (ES) cells through gene targeting. Telomerase inactivation in ES cells results in progressive telomere shortening. Telomere DNA damage in ES cells and neural progenitor cells induces rapid apoptosis when telomeres are uncapped, in contrast to fibroblast cells that enter a state of replicative senescence. Significantly, telomerase inactivation limits the proliferation capacity of human ES cells without affecting their pluripotency. By targeting telomerase activity, we can functionally separate the two unique properties of human pluripotent stem cells, namely unlimited self-renewal and pluripotency. We show that the potential of ES cells to form teratomas in vivo is dictated by their telomere length. By controlling telomere length of ES cells through telomerase inactivation, we can inhibit teratoma formation and potentially improve the safety of cell therapies involving terminally differentiated cells as well as specific progenitor cells that do not require sustained cellular proliferation in vivo, and thus sustained telomerase activity. Stem Cells 2016;34:2471-2484.
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Affiliation(s)
| | - Dong Liang Ma
- Neuroscience Academic Clinical Programme.,Department of Research, National Neuroscience Institute, Singapore
| | | | - XiuBo Fan
- Cancer and Stem Cell Biology Programme.,Department of Hematology, Singapore General Hospital, Singapore
| | - Zhiyong Poon
- BioSystems and Micromechanics, , Singapore-MIT Alliance for Research & Technology, Singapore
| | | | | | | | - William Ying Khee Hwang
- Cancer and Stem Cell Biology Programme.,Department of Hematology, Singapore General Hospital, Singapore
| | - Vinay Tergaonkar
- Division of Cancer Genetics and Therapeutics, Institute of Molecular and Cell Biology (IMCB), Singapore.,Department of Biochemistry.,Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, Australia
| | | | - Sujoy Ghosh
- Cardiovascular and Metabolic Disorders Programme, Duke-NUS Medical School, Singapore
| | | | - Eyleen L K Goh
- Neuroscience Academic Clinical Programme.,Department of Research, National Neuroscience Institute, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,KK Women's and Children's Hospital, KK Research Center, Singapore
| | - Shang Li
- Cancer and Stem Cell Biology Programme. .,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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20
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Central nervous system myeloid cells as drug targets: current status and translational challenges. Nat Rev Drug Discov 2015; 15:110-24. [DOI: 10.1038/nrd.2015.14] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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21
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Melicher D, Buzas EI, Falus A. Genetic and epigenetic trends in telomere research: a novel way in immunoepigenetics. Cell Mol Life Sci 2015; 72:4095-109. [PMID: 26190020 PMCID: PMC11113282 DOI: 10.1007/s00018-015-1991-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/25/2015] [Accepted: 07/10/2015] [Indexed: 01/09/2023]
Abstract
Telomeres are protective heterochromatic structures that cap the end of linear chromosomes and play a key role in preserving genomic stability. Telomere length represents a balance between processes that shorten telomeres during cell divisions with incomplete DNA replication and the ones that lengthen telomeres by the action of telomerase, an RNA-protein complex with reverse transcriptase activity which adds telomeric repeats to DNA molecule ends. Telomerase activity and telomere length have a crucial role in cellular ageing and in the pathobiology of several human diseases attracting intense research. The last few decades have witnessed remarkable advances in our understanding about telomeres, telomere-associated proteins, and the biogenesis and regulation of the telomerase holoenzyme complex, as well as about telomerase activation and the telomere-independent functions of telomerase. Emerging data have revealed that telomere length can be modified by genetic and epigenetic factors, sex hormones, reactive oxygen species and inflammatory reactions. It has become clear that, in order to find out more about the factors influencing the rate of telomere attrition in vivo, it is crucial to explore both genetic and epigenetic mechanisms. Since the telomere/telomerase assembly is under the control of multiple epigenetic influences, the unique design of twin studies could help disentangle genetic and environmental factors in the functioning of the telomere/telomerase system. It is surprising that the literature on twin studies investigating this topic is rather scarce. This review aims to provide an overview of some important immune response- and epigenetics-related aspects of the telomere/telomerase system demanding more research, while presenting the available twin data published in connection with telomere research so far. By emphasising what we know and what we still do not know in these areas, another purpose of this review is to urge more twin studies in telomere research.
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Affiliation(s)
- Dora Melicher
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Budapest, Hungary
| | - Edit I Buzas
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Budapest, Hungary
| | - Andras Falus
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Budapest, Hungary.
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22
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Abstract
'Cellular senescence', a term originally defining the characteristics of cultured cells that exceed their replicative limit, has been broadened to describe durable states of proliferative arrest induced by disparate stress factors. Proposed relationships between cellular senescence, tumour suppression, loss of tissue regenerative capacity and ageing suffer from lack of uniform definition and consistently applied criteria. Here, we highlight caveats in interpreting the importance of suboptimal senescence-associated biomarkers, expressed either alone or in combination. We advocate that more-specific descriptors be substituted for the now broadly applied umbrella term 'senescence' in defining the suite of diverse physiological responses to cellular stress.
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Affiliation(s)
- Norman E Sharpless
- Department of Medicine and Genetics and The Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7295, USA
| | - Charles J Sherr
- Department of Tumor Cell Biology and The Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-2794, USA
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23
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Reste J, Zvigule G, Zvagule T, Kurjane N, Eglite M, Gabruseva N, Berzina D, Plonis J, Miklasevics E. Telomere length in Chernobyl accident recovery workers in the late period after the disaster. JOURNAL OF RADIATION RESEARCH 2014; 55:1089-100. [PMID: 25015931 PMCID: PMC4229925 DOI: 10.1093/jrr/rru060] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 06/08/2014] [Accepted: 06/09/2014] [Indexed: 05/02/2023]
Abstract
The outcome of the Chernobyl nuclear power plant (CNPP) accident was that a huge number of people were exposed to ionizing radiation. Previous studies of CNPP clean-up workers from Latvia revealed a high occurrence of age-associated degenerative diseases and cancer in young adults, as well as a high mortality as a result of cardiovascular disorders at age 45-54 years. DNA tandem repeats that cap chromosome ends, known as telomeres, are sensitive to oxidative damage and exposure to ionizing radiation. Telomeres are important in aging processes and carcinogenesis. The aim of this study was to investigate the long-term effect of protracted ionizing radiation exposure on telomere length in CNPP clean-up workers. Relative telomere length (RTL) was measured in peripheral blood leukocytes of 595 CNPP clean-up workers and 236 gender- and age-matched controls using real-time quantitative polymerase chain reaction (q-PCR). Close attention was paid to participation year and tasks performed during the worker's stay in Chernobyl, health status, and RTL differences between subgroups. Telomere shortening was not found in CNPP clean-up workers; on the contrary, their RTL was slightly greater than in controls (P = 0.001). Longer telomeres were found in people who worked during 1986, in those undertaking 'dirty' tasks (digging and deactivation), and in people with cancer. Shorter telomeres appeared frequently in those with cataract, osteoporosis, atherosclerosis, or coronary heart disease. We conclude that the longer telomeres revealed in people more heavily exposed to ionizing radiation probably indicate activation of telomerase as a chromosome healing mechanism following damage, and reflect defects in telomerase regulation that could potentiate carcinogenesis.
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Affiliation(s)
- Jelena Reste
- Institute of Occupational Safety and Environmental Health, Riga Stradins University, Dzirciema Street 16, Riga, LV-1007, Latvia Centre of Occupational and Radiological Medicine, Pauls Stradins Clinical University Hospital, Pilsonu Street 13, Riga, LV-1002, Latvia
| | - Gunda Zvigule
- Institute of Oncology, Riga Stradins University, Dzirciema Street 16, Riga, LV-1007, Latvia
| | - Tija Zvagule
- Institute of Occupational Safety and Environmental Health, Riga Stradins University, Dzirciema Street 16, Riga, LV-1007, Latvia Centre of Occupational and Radiological Medicine, Pauls Stradins Clinical University Hospital, Pilsonu Street 13, Riga, LV-1002, Latvia
| | - Natalja Kurjane
- Institute of Occupational Safety and Environmental Health, Riga Stradins University, Dzirciema Street 16, Riga, LV-1007, Latvia Centre of Occupational and Radiological Medicine, Pauls Stradins Clinical University Hospital, Pilsonu Street 13, Riga, LV-1002, Latvia
| | - Maija Eglite
- Institute of Occupational Safety and Environmental Health, Riga Stradins University, Dzirciema Street 16, Riga, LV-1007, Latvia Centre of Occupational and Radiological Medicine, Pauls Stradins Clinical University Hospital, Pilsonu Street 13, Riga, LV-1002, Latvia
| | - Natalija Gabruseva
- Centre of Occupational and Radiological Medicine, Pauls Stradins Clinical University Hospital, Pilsonu Street 13, Riga, LV-1002, Latvia
| | - Dace Berzina
- Institute of Oncology, Riga Stradins University, Dzirciema Street 16, Riga, LV-1007, Latvia
| | - Juris Plonis
- Institute of Oncology, Riga Stradins University, Dzirciema Street 16, Riga, LV-1007, Latvia
| | - Edvins Miklasevics
- Institute of Oncology, Riga Stradins University, Dzirciema Street 16, Riga, LV-1007, Latvia
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24
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Harland JL, Chang YT, Moser BA, Nakamura TM. Tpz1-Ccq1 and Tpz1-Poz1 interactions within fission yeast shelterin modulate Ccq1 Thr93 phosphorylation and telomerase recruitment. PLoS Genet 2014; 10:e1004708. [PMID: 25330395 PMCID: PMC4199508 DOI: 10.1371/journal.pgen.1004708] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 08/26/2014] [Indexed: 11/22/2022] Open
Abstract
In both fission yeast and humans, the shelterin complex plays central roles in regulation of telomerase recruitment, protection of telomeres against DNA damage response factors, and formation of heterochromatin at telomeres. While shelterin is essential for limiting activation of the DNA damage checkpoint kinases ATR and ATM at telomeres, these kinases are required for stable maintenance of telomeres. In fission yeast, Rad3ATR and Tel1ATM kinases are redundantly required for telomerase recruitment, since Rad3ATR/Tel1ATM-dependent phosphorylation of the shelterin subunit Ccq1 at Thr93 promotes interaction between Ccq1 and the telomerase subunit Est1. However, it remained unclear how protein-protein interactions within the shelterin complex (consisting of Taz1, Rap1, Poz1, Tpz1, Pot1 and Ccq1) contribute to the regulation of Ccq1 Thr93 phosphorylation and telomerase recruitment. In this study, we identify domains and amino acid residues that are critical for mediating Tpz1-Ccq1 and Tpz1-Poz1 interaction within the fission yeast shelterin complex. Using separation of function Tpz1 mutants that maintain Tpz1-Pot1 interaction but specifically disrupt either Tpz1-Ccq1 or Tpz1-Poz1 interaction, we then establish that Tpz1-Ccq1 interaction promotes Ccq1 Thr93 phosphorylation, telomerase recruitment, checkpoint inhibition and telomeric heterochromatin formation. Furthermore, we demonstrate that Tpz1-Poz1 interaction promotes telomere association of Poz1, and loss of Poz1 from telomeres leads to increases in Ccq1 Thr93 phosphorylation and telomerase recruitment, and telomeric heterochromatin formation defect. In addition, our studies establish that Tpz1-Poz1 and Tpz1-Ccq1 interactions redundantly fulfill the essential telomere protection function of the shelterin complex, since simultaneous loss of both interactions caused immediate loss of cell viability for the majority of cells and generation of survivors with circular chromosomes. Based on these findings, we suggest that the negative regulatory function of Tpz1-Poz1 interaction works upstream of Rad3ATR kinase, while Tpz1-Ccq1 interaction works downstream of Rad3ATR kinase to facilitate Ccq1 Thr93 phosphorylation and telomerase recruitment. Proper maintenance of telomeres is essential for maintaining genomic stability, and genomic instability caused by dysfunctional telomeres could lead to accumulation of mutations that may drive tumor formation. Telomere dysfunction has also been linked to premature aging caused by depletion of stem cells. Therefore, it is important to understand how cells ensure proper maintenance of telomeres. Mammalian cells and fission yeast cells utilize an evolutionarily conserved multi-subunit telomere protection complex called shelterin to ensure protection against telomere fusions by DNA repair factors and cell cycle arrest by DNA damage checkpoint kinases. However, previous studies have not yet fully established how protein-protein interactions within the shelterin complex contribute to the regulation of DNA damage checkpoint signaling and telomerase recruitment. By utilizing separation of function mutations that specifically disrupt either Tpz1-Ccq1 or Tpz1-Poz1 interaction within the fission yeast shelterin, we establish that Tpz1-Ccq1 interaction is essential for phosphorylation of Ccq1 by the DNA damage checkpoint kinases Rad3ATR and Tel1ATM that is needed for telomerase recruitment to telomeres, while Tpz1-Poz1 interaction prevents Ccq1 phosphorylation by promoting Poz1 association with telomeres. These findings thus establish for the first time how protein-protein interactions within the shelterin complex modulate checkpoint kinase-dependent phosphorylation essential for telomerase recruitment.
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Affiliation(s)
- Jennifer L. Harland
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Ya-Ting Chang
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Bettina A. Moser
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Toru M. Nakamura
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
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25
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Tamayo M, Pértega S, Mosquera A, Rodríguez M, Blanco FJ, Fernández-Sueiro JL, Gosálvez J, Fernández JL. Individual telomere length decay in patients with spondyloarthritis. Mutat Res 2014; 765:1-5. [PMID: 24769426 DOI: 10.1016/j.mrfmmm.2014.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/10/2014] [Accepted: 04/12/2014] [Indexed: 11/17/2022]
Abstract
Telomere length was sequentially determined in peripheral blood leukocytes (PBL) from patients with ankylosing spondylitis (AS; n = 44) and psoriatic arthritis (PsA; n = 42) followed through 2.93 ± 0.99 years, using a quantitative PCR (qPCR) assay. The initial telomere size from PsA patients was higher than those with cutaneous psoriasis only (n = 53), possibly due to the inflammatory condition. The qPCR assay was sensitive enough to evidence a significant telomere length shortening in PBL from practically all subjects and PsA patients showed a higher rate of loss of telomere sequence than patients with AS during the follow-up time.
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Affiliation(s)
- María Tamayo
- Genetics Unit, INIBIC-Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias, 84, 15006 A Coruña, Spain; Laboratorio de Genética Molecular y Radiobiología, Centro Oncológico de Galicia, c/ Doctor Camilo Veiras n°1, 15009 A Coruña, Spain
| | - Sonia Pértega
- Clinical Epidemiology and Biostatistics Unit, INIBIC-Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias, 84, 15006 A Coruña, Spain
| | - Alejandro Mosquera
- Genetics Unit, INIBIC-Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias, 84, 15006 A Coruña, Spain
| | - Montserrat Rodríguez
- Genetics Unit, INIBIC-Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias, 84, 15006 A Coruña, Spain
| | - Francisco J Blanco
- Rheumatology Division, INIBIC-Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias, 84, 15006 A Coruña, Spain
| | - José Luis Fernández-Sueiro
- Rheumatology Division, INIBIC-Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias, 84, 15006 A Coruña, Spain
| | - Jaime Gosálvez
- Unidad de Genética, Facultad de Biología, Universidad Autónoma de Madrid, Spain
| | - José Luis Fernández
- Genetics Unit, INIBIC-Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias, 84, 15006 A Coruña, Spain; Laboratorio de Genética Molecular y Radiobiología, Centro Oncológico de Galicia, c/ Doctor Camilo Veiras n°1, 15009 A Coruña, Spain.
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Zanni GR, Wick JY. Telomeres: unlocking the mystery of cell division and aging. ACTA ACUST UNITED AC 2014; 26:78-90. [PMID: 21310705 DOI: 10.4140/tcp.n.2011.78] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Telomeres are DNA sequences that cap the ends of chromosomes, protecting them from fraying and fusing together during replication. During replication, telomeres lose some of their genetic material but are repaired by the ribonucleoprotein telomerase. Both telomeres and telomerase are linked to cell senescence and apoptosis, and research suggests they play key roles in aging, cancer, hereditary syndromes, and chronic diseases. Several theories of aging are reviewed along with the potential impact of telomerase in developing new treatments.
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Affiliation(s)
- Guido R Zanni
- psychologist and health systems consultant, Alexandria, Virginia
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27
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Popuri V, Hsu J, Khadka P, Horvath K, Liu Y, Croteau DL, Bohr VA. Human RECQL1 participates in telomere maintenance. Nucleic Acids Res 2014; 42:5671-88. [PMID: 24623817 PMCID: PMC4027191 DOI: 10.1093/nar/gku200] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
A variety of human tumors employ alternative and recombination-mediated lengthening for telomere maintenance (ALT). Human RecQ helicases, such as BLM and WRN, can efficiently unwind alternate/secondary structures during telomere replication and/or recombination. Here, we report a novel role for RECQL1, the most abundant human RecQ helicase but functionally least studied, in telomere maintenance. RECQL1 associates with telomeres in ALT cells and actively resolves telomeric D-loops and Holliday junction substrates. RECQL1 physically and functionally interacts with telomere repeat-binding factor 2 that in turn regulates its helicase activity on telomeric substrates. The telomeric single-stranded binding protein, protection of telomeres 1 efficiently stimulates RECQL1 on telomeric substrates containing thymine glycol, a replicative blocking lesion. Loss of RECQL1 results in dysfunctional telomeres, telomere loss and telomere shortening, elevation of telomere sister-chromatid exchanges and increased aphidicolin-induced telomere fragility, indicating a role for RECQL1 in telomere maintenance. Further, our results indicate that RECQL1 may participate in the same pathway as WRN, probably in telomere replication.
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Affiliation(s)
- Venkateswarlu Popuri
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224, USA
| | - Joseph Hsu
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224, USA
| | - Prabhat Khadka
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224, USA
| | - Kent Horvath
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224, USA
| | - Yie Liu
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224, USA
| | - Deborah L Croteau
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224, USA
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd, Suite 100, Baltimore, MD 21224, USA
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Yamamoto M, Bando T, Kawamoto Y, Taylor RD, Hashiya K, Sugiyama H. Specific Alkylation of Human Telomere Repeat Sequences by a Tandem-Hairpin Motif of Pyrrole–Imidazole Polyamides with Indole-seco-CBI. Bioconjug Chem 2014; 25:552-9. [DOI: 10.1021/bc400567m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
| | | | | | | | | | - Hiroshi Sugiyama
- Core
Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation (JST), Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
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29
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Bender HS, Marshall Graves JA, Deakin JE. Pathogenesis and molecular biology of a transmissible tumor in the Tasmanian devil. Annu Rev Anim Biosci 2013; 2:165-87. [PMID: 25384139 DOI: 10.1146/annurev-animal-022513-114204] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The emergence of a fatal transmissible cancer known as devil facial tumor disease (DFTD) is threatening the iconic Tasmanian devil with extinction in the wild within the next few decades. Since the first report of the disease in 1996, DFTD has spread to over 85% of the devils' distribution and dramatically reduced devil numbers. Research into DFTD has focused on gaining a deeper understanding of the disease on multiple levels, including an accurate assessment of the tissue origin of the tumor, elucidation of how the tumor evades immune detection, and determination of how the tumor is transmitted between individuals and how it is evolving as it spreads through the population. Knowledge gained from these studies has important implications for DFTD management and devil conservation.
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Affiliation(s)
- Hannah S Bender
- Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
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30
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Cdk1 regulates the temporal recruitment of telomerase and Cdc13-Stn1-Ten1 complex for telomere replication. Mol Cell Biol 2013; 34:57-70. [PMID: 24164896 DOI: 10.1128/mcb.01235-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
In budding yeast (Saccharomyces cerevisiae), the cell cycle-dependent telomere elongation by telomerase is controlled by the cyclin-dependent kinase 1 (Cdk1). The telomere length homeostasis is balanced between telomerase-unextendable and telomerase-extendable states that both require Cdc13. The recruitment of telomerase complex by Cdc13 promotes telomere elongation, while the formation of Cdc13-Stn1-Ten1 (CST) complex at the telomere blocks telomere elongation by telomerase. However, the cellular signaling that regulates the timing of the telomerase-extendable and telomerase-unextendable states is largely unknown. Phosphorylation of Cdc13 by Cdk1 promotes the interaction between Cdc13 and Est1 and hence telomere elongation. Here, we show that Cdk1 also phosphorylates Stn1 at threonine 223 and serine 250 both in vitro and in vivo, and these phosphorylation events are essential for the stability of the CST complexes at the telomeres. By controlling the timing of Cdc13 and Stn1 phosphorylations during cell cycle progression, Cdk1 regulates the temporal recruitment of telomerase complexes and CST complexes to the telomeres to facilitate telomere maintenance.
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Abstract
Mammalian aging is associated with reduced tissue regeneration, increased degenerative disease, and cancer. Because stem cells regenerate many adult tissues and contribute to the development of cancer by accumulating mutations, age-related changes in stem cells likely contribute to age-related morbidity. Consistent with this, stem cell function declines with age in numerous tissues as a result of gate-keeping tumor suppressor expression, DNA damage, changes in cellular physiology, and environmental changes in tissues. It remains unknown whether declines in stem cell function during aging influence organismal longevity. However, mechanisms that influence longevity also modulate age-related morbidity, partly through effects on stem cells.
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Affiliation(s)
- Robert A J Signer
- Children's Research Institute, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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32
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Leufke C, Leykauf J, Krunic D, Jauch A, Holtgreve-Grez H, Böhm-Steuer B, Bröcker EB, Mauch C, Utikal J, Hartschuh W, Purdie KJ, Boukamp P. The telomere profile distinguishes two classes of genetically distinct cutaneous squamous cell carcinomas. Oncogene 2013; 33:3506-18. [DOI: 10.1038/onc.2013.323] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 05/14/2013] [Accepted: 06/17/2013] [Indexed: 12/12/2022]
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33
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Mompart F, Robelin D, Delcros C, Yerle-Bouissou M. 3D organization of telomeres in porcine neutrophils and analysis of LPS-activation effect. BMC Cell Biol 2013; 14:30. [PMID: 23803152 PMCID: PMC3701612 DOI: 10.1186/1471-2121-14-30] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 06/12/2013] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND While the essential role of 3D nuclear architecture on nuclear functions has been demonstrated for various cell types, information available for neutrophils, essential components of the immune system, remains limited. In this study, we analysed the spatial arrangements of telomeres which play a central role in cell fate. Our studies were carried out in swine, which is an excellent model organism for both biomedical research and agronomic applications. We isolated bacterial artificial chromosome (BAC)-containing subtelomeric p and q sequences specific to each porcine chromosome. This allowed us to study the behaviour of p and q telomeres of homologous chromosomes for seven pairs chosen for their difference in length and morphology. This was performed using 3D-FISH on structurally preserved neutrophils, and confocal microscopy. Resting and lipopolysaccharide (LPS)-activated states were investigated to ascertain whether a response to a pathogen aggression modifies this organization. RESULTS The positions of the p and q telomeres relative to the nuclear outer border were determined in the two states. All p telomeres changed their position significantly during the activation process, although the effect was less pronounced for the q telomeres. The patterns of telomeric associations between homologs and their frequencies were analysed for 7 pairs of chromosomes. This analysis revealed that the distribution of pp, qq and pq associations differs significantly among the 7 chromosomes. This distribution does not fit with the theoretical distribution for each chromosome, suggesting that preferential associations occur between subtelomeres. CONCLUSIONS The percentage of nuclei harbouring at least one telomeric association between homologs varies significantly among the chromosomes, the smallest metacentric chromosome SSC12, which is also the richest in gene-density, harbouring the highest value. The distribution of types of telomeric associations is highly dependent on the chromosomes and is not affected by the activation process. The frequencies of telomeric associations are also highly dependent on the type of association and the type of chromosome. Overall, the LPS-activation process induces only minor changes in these patterns of associations. When telomeric associations occur, the associations of p and q arms from the same chromosome are the most frequent, suggesting that "chromosome bending" occurs in neutrophils as previously observed in gametes.
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Affiliation(s)
- Florence Mompart
- INRA, UMR 444, Génétique Cellulaire, F-31326 Castanet, Tolosan, France
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34
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Pfeiffer V, Lingner J. Replication of telomeres and the regulation of telomerase. Cold Spring Harb Perspect Biol 2013; 5:a010405. [PMID: 23543032 DOI: 10.1101/cshperspect.a010405] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Telomeres are the physical ends of eukaryotic chromosomes. They protect chromosome ends from DNA degradation, recombination, and DNA end fusions, and they are important for nuclear architecture. Telomeres provide a mechanism for their replication by semiconservative DNA replication and length maintenance by telomerase. Through telomerase repression and induced telomere shortening, telomeres provide the means to regulate cellular life span. In this review, we introduce the current knowledge on telomere composition and structure. We then discuss in depth the current understanding of how telomere components mediate their function during semiconservative DNA replication and how telomerase is regulated at the end of the chromosome. We focus our discussion on the telomeres from mammals and the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe.
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Affiliation(s)
- Verena Pfeiffer
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Frontiers in Genetics National Center of Competence in Research, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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35
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Guo L, Li J, Qiao X, Yu M, Tang W, Wang H, Guo W, Tian W. Comparison of odontogenic differentiation of human dental follicle cells and human dental papilla cells. PLoS One 2013; 8:e62332. [PMID: 23620822 PMCID: PMC3631153 DOI: 10.1371/journal.pone.0062332] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 03/20/2013] [Indexed: 02/05/2023] Open
Abstract
Classical tooth development theory suggests that dental papilla cells (DPCs) are the precursor cells of odontoblasts, which are responsible for dentin development. However, our previous studies have indicated that dental follicle cells (DFCs) can differentiate into odontoblasts. To further our understanding of tooth development, and the differences in dentinogenesis between DFCs and DPCs, the odontogenic differentiation of DFCs and DPCs was characterized in vitro and in vivo. DFCs and DPCs were individually combined with treated dentin matrix (TDM) before they were subcutaneously implanted into the dorsum of mice for 8 weeks. Results showed that 12 proteins were significantly differential, and phosphoserine aminotransferase 1 (PSAT1), Isoform 2 of hypoxia-inducible factor 1-alpha (HIF1A) and Isoform 1 of annexin A2 (ANXA2), were the most significantly differential proteins. These proteins are related to regulation of bone balance, angiogenesis and cell survival in an anoxic environment. Both DFCs and DPCs express odontogenic, neurogenic and peridontogenic markers. Histological examination of the harvested grafts showed that both DFCs and DPCs form pulp-dentin/cementum-periodentium-like tissues in vivo. Hence, DFCs and DPCs have similar odontogenic differentiation potential in the presence of TDM. However, differences in glucose and amino acid metabolism signal transduction and protein synthesis were observed for the two cell types. This study expands our understanding on tooth development, and provides direct evidence for the use of alternative cell sources in tooth regeneration.
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Affiliation(s)
- Lijuan Guo
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, P.R. China
- Department of Oral and Maxillofacial Surgery, West China School of Stomatology, Sichuan University, Chengdu, P.R. China
| | - Jie Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, P.R. China
- College of Life Science, Sichuan University, Chengdu, P.R. China
| | - Xiangchen Qiao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, P.R. China
| | - Mei Yu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, P.R. China
| | - Wei Tang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, P.R. China
- Department of Oral and Maxillofacial Surgery, West China School of Stomatology, Sichuan University, Chengdu, P.R. China
| | - Hang Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, P.R. China
- Department of Oral and Maxillofacial Surgery, West China School of Stomatology, Sichuan University, Chengdu, P.R. China
| | - Weihua Guo
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, P.R. China
- Department of Pedodontics, West China School of Stomatology, Sichuan University, Chengdu, P.R. China
- * E-mail: (WG); (WT)
| | - Weidong Tian
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, P.R. China
- Department of Oral and Maxillofacial Surgery, West China School of Stomatology, Sichuan University, Chengdu, P.R. China
- * E-mail: (WG); (WT)
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36
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Neumann AA, Watson CM, Noble JR, Pickett HA, Tam PPL, Reddel RR. Alternative lengthening of telomeres in normal mammalian somatic cells. Genes Dev 2013; 27:18-23. [PMID: 23307865 DOI: 10.1101/gad.205062.112] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Some cancers use alternative lengthening of telomeres (ALT), a mechanism whereby new telomeric DNA is synthesized from a DNA template. To determine whether normal mammalian tissues have ALT activity, we generated a mouse strain containing a DNA tag in a single telomere. We found that the tagged telomere was copied by other telomeres in somatic tissues but not the germline. The tagged telomere was also copied by other telomeres when introgressed into CAST/EiJ mice, which have telomeres more similar in length to those of humans. We conclude that ALT activity occurs in normal mouse somatic tissues.
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Affiliation(s)
- Axel A Neumann
- Cancer Research Unit, Children's Medical Research Institute, Westmead, New South Wales, Australia
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37
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Abstract
The telomeric region of repetitive DNA sequences at the end of chromosomes prevents end-to-end fusion of chromosome terminals and deterioration of the doublestrand free ends. Because of the 'end-replication problem', telomeres shorten with each round of cell division, resulting in cell senescence. The enzyme telomerase compensates for telomere shortening by elongating telomeric sequences, thereby prolonging the lifespan of the cell. Studies of articular cartilage and bone tissues have indicated that telomere shortening limits normal cell function and proliferation, while the telomere maintenance mechanisms of osteosarcoma cells facilitate escape from cell death and promote immortality. This article reviews the literature on this topic and provides an extensive discussion of the basic molecular biology and roles of telomeres and telomerase in musculoskeletal diseases such as osteoarthritis, osteoporosis and osteosarcoma. Findings to date suggest that telomeres and telomerase may become novel therapeutic targets for the diagnosis, treatment and prevention of musculoskeletal disorders.
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Affiliation(s)
- D Li
- Department of Orthopaedics, The Second Xiangya Hospital of Central South University, Changsha, China
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38
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Marshall AL, Christiani DC. Genetic susceptibility to lung cancer--light at the end of the tunnel? Carcinogenesis 2013; 34:487-502. [PMID: 23349013 DOI: 10.1093/carcin/bgt016] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Lung cancer is one of the most common and deadliest cancers in the world. The major socio-environmental risk factor involved in the development of lung cancer is cigarette smoking. Additionally, there are multiple genetic factors, which may also play a role in lung cancer risk. Early work focused on the presence of relatively prevalent but low-penetrance alterations in candidate genes leading to increased risk of lung cancer. Development of new technologies such as genomic profiling and genome-wide association studies has been helpful in the detection of new genetic variants likely involved in lung cancer risk. In this review, we discuss the role of multiple genetic variants and review their putative role in the risk of lung cancer. Identifying genetic biomarkers and patterns of genetic risk may be useful in the earlier detection and treatment of lung cancer patients.
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Affiliation(s)
- Ariela L Marshall
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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39
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Neumann AA, Watson CM, Noble JR, Pickett HA, Tam PPL, Reddel RR. Alternative lengthening of telomeres in normal mammalian somatic cells. Genes Dev 2013. [PMID: 23307865 DOI: 10.1101/gad.205062.112.freely] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Some cancers use alternative lengthening of telomeres (ALT), a mechanism whereby new telomeric DNA is synthesized from a DNA template. To determine whether normal mammalian tissues have ALT activity, we generated a mouse strain containing a DNA tag in a single telomere. We found that the tagged telomere was copied by other telomeres in somatic tissues but not the germline. The tagged telomere was also copied by other telomeres when introgressed into CAST/EiJ mice, which have telomeres more similar in length to those of humans. We conclude that ALT activity occurs in normal mouse somatic tissues.
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Affiliation(s)
- Axel A Neumann
- Cancer Research Unit, Children's Medical Research Institute, Westmead, New South Wales, Australia
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40
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Fick L, Fick G, Li Z, Cao E, Bao B, Heffelfinger D, Parker H, Ostrander E, Riabowol K. Telomere Length Correlates with Life Span of Dog Breeds. Cell Rep 2012; 2:1530-6. [DOI: 10.1016/j.celrep.2012.11.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 08/24/2012] [Accepted: 11/27/2012] [Indexed: 10/27/2022] Open
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41
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Garrels W, Kues WB, Herrmann D, Holler S, Baulain U, Niemann H. Ectopic expression of human telomerase RNA component results in increased telomerase activity and elongated telomeres in bovine blastocysts. Biol Reprod 2012; 87:95. [PMID: 22855562 DOI: 10.1095/biolreprod.112.100198] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Telomeres play an important role in aging, and are critical for the regenerative capacity of mammalian cells. The holoenzyme telomerase rebuilds telomeres and is composed of two components, the catalytic protein telomerase reverse transcriptase (TERT) and the telomerase RNA (TERC). TERC is ubiquitously expressed in somatic cells and is thought to have no regulatory effects on telomerase activity. Transgenic expression of human TERT (hTERT) in bovine somatic and embryonic cells extends telomere length and enhances telomerase activity. To obtain further insight into the regulatory capacity of the two telomerase components, we have studied the ability of hTERC and hTERT to increase telomerase activity and telomere length in bovine embryos. Expression plasmids for the human RNA component (hTERC) and/or the catalytic subunit of human telomerase (hTERT), respectively, were injected into the cytoplasm of in vitro-produced bovine zygotes. Ectopic expression of hTERC increased telomerase activity and telomere length in bovine blastocysts. Coexpression of hTERT and hTERC did not result in further telomere elongation when compared to the hTERC group. These data indicate that TERC is one of the limiting factors of telomerase activity in bovine blastocysts, and further establish bovine preimplantation embryos as a useful model to modulate telomere length with impact for basic embryology and derivation of pluripotent cells.
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Affiliation(s)
- Wiebke Garrels
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Mariensee, Neustadt, Germany
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42
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Bender HS, Murchison EP, Pickett HA, Deakin JE, Strong MA, Conlan C, McMillan DA, Neumann AA, Greider CW, Hannon GJ, Reddel RR, Graves JAM. Extreme telomere length dimorphism in the Tasmanian devil and related marsupials suggests parental control of telomere length. PLoS One 2012; 7:e46195. [PMID: 23049977 PMCID: PMC3458001 DOI: 10.1371/journal.pone.0046195] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 08/27/2012] [Indexed: 01/21/2023] Open
Abstract
Telomeres, specialised structures that protect chromosome ends, play a critical role in preserving chromosome integrity. Telomere dynamics in the Tasmanian devil (Sarcophilus harrisii) are of particular interest in light of the emergence of devil facial tumour disease (DFTD), a transmissible malignancy that causes rapid mortality and threatens the species with extinction. We used fluorescent in situ hybridisation to investigate telomere length in DFTD cells, in healthy Tasmanian devils and in four closely related marsupial species. Here we report that animals in the Order Dasyuromorphia have chromosomes characterised by striking telomere length dimorphism between homologues. Findings in sex chromosomes suggest that telomere length dimorphism may be regulated by events in the parental germlines. Long telomeres on the Y chromosome imply that telomere lengthening occurs during spermatogenesis, whereas telomere diminution occurs during oogenesis. Although found in several somatic cell tissue types, telomere length dimorphism was not found in DFTD cancer cells, which are characterised by uniformly short telomeres. This is, to our knowledge, the first report of naturally occurring telomere length dimorphism in any species and suggests a novel strategy of telomere length control. Comparative studies in five distantly related marsupials and a monotreme indicate that telomere dimorphism evolved at least 50 million years ago.
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Affiliation(s)
- Hannah S Bender
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia.
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43
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Selected telomere length changes and aberrant three-dimensional nuclear telomere organization during fast-onset mouse plasmacytomas. Neoplasia 2012; 14:344-51. [PMID: 22577349 DOI: 10.1593/neo.12446] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Revised: 03/30/2012] [Accepted: 04/01/2012] [Indexed: 12/30/2022] Open
Abstract
Mouse plasmacytoma (PCT) can develop within 45 days when induced by a v-abl/myc replication-deficient retrovirus. This fast-onset PCT development is always associated with trisomy of cytoband E2 of mouse chromosome 11 (11E2). Trisomy of 11E2 was identified as the sole aberration in all fast-onset mouse PCTs in [T38HxBALB/c]N congenic mice, with a reciprocal translocation between chromosome X and 11 (rcpT(X;11)) (Genes Cancer 2010;1:847-858). Using this mouse model, we have now examined the overall and individual telomere lengths in fast-onset PCTs compared with normal B cells using two-dimensional and three-dimensional quantitative fluorescent in situ hybridization of telomeres. We found fast-onset PCTs to have a significantly different three-dimensional telomere profile, compared with primary B cells of wild-type littermates with and without rcpT(X;11) (P < .0001 and P = .006, respectively). Our data also indicate for primary PCT cells, from the above mouse strain, that the translocation chromosome carrying 11E2 is the only chromosome with telomere lengthening (P = 4 x 10(-16)). This trend is not seen for T(X;11) in primary B cells of control [T38HxBALB/c]N mice with the rcpT(X;11). This finding supports the concept of individual telomere lengthening of chromosomes that are functionally important for the tumorigenic process.
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44
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Three-dimensional Telomere Signatures of Hodgkin- and Reed-Sternberg Cells at Diagnosis Identify Patients with Poor Response to Conventional Chemotherapy. Transl Oncol 2012; 5:269-77. [PMID: 22937179 DOI: 10.1593/tlo.12142] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 05/07/2012] [Accepted: 07/15/2012] [Indexed: 12/13/2022] Open
Abstract
In classic Hodgkin lymphoma (HL) the malignant mononuclear Hodgkin (H) and multinuclear Reed-Sternberg (RS) cells are characterized by a distinct three-dimensional nuclear telomere organization with shortening of the telomere length and the formation of telomeric aggregates. We asked if the severity of these telomere changes correlates with the clinical behavior of the disease. We retrospectively evaluated three-dimensional telomere organization by quantitative fluorescent in situ hybridization (Q-FISH) of diagnostic biopsies from 16 patients who were good responders and compared them with 16 diagnostic biopsies of 10 patients with refractory or relapsing HL (eight initial biopsies, four confirming progressions, and four confirming relapses). The H cells from patients with refractory/relapsing disease contained a significantly higher percentage of very small telomeres (P = .027) and telomere aggregates (P = .032) compared with H cells of patients entering rapid remission. These differences were even more significant (P = .002 and P = .013, respectively) when comparing the eight initial diagnostic biopsies of refractory/relapsing HL with diagnostic biopsies of eight patients with ongoing long-lasting remission (mean of 47 months). This specific three-dimensional telomere Q-FISH signature identifies these highly aggressive mononuclear H cells at the first diagnostic biopsy and thus may offer a new molecular marker to optimize initial treatment.
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45
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Aubert G, Baerlocher GM, Vulto I, Poon SS, Lansdorp PM. Collapse of telomere homeostasis in hematopoietic cells caused by heterozygous mutations in telomerase genes. PLoS Genet 2012; 8:e1002696. [PMID: 22661914 PMCID: PMC3355073 DOI: 10.1371/journal.pgen.1002696] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 03/20/2012] [Indexed: 01/03/2023] Open
Abstract
Telomerase activity is readily detectable in extracts from human hematopoietic stem and progenitor cells, but appears unable to maintain telomere length with proliferation in vitro and with age in vivo. We performed a detailed study of the telomere length by flow FISH analysis in leukocytes from 835 healthy individuals and 60 individuals with reduced telomerase activity. Healthy individuals showed a broad range in average telomere length in granulocytes and lymphocytes at any given age. The average telomere length declined with age at a rate that differed between age-specific breakpoints and between cell types. Gender differences between leukocyte telomere lengths were observed for all cell subsets studied; interestingly, this trend could already be detected at birth. Heterozygous carriers for mutations in either the telomerase reverse transcriptase (hTERT) or the telomerase RNA template (hTERC) gene displayed striking and comparable telomere length deficits. Further, non-carrier relatives of such heterozygous individuals had somewhat shorter leukocyte telomere lengths than expected; this difference was most profound for granulocytes. Failure to maintain telomere homeostasis as a result of partial telomerase deficiency is thought to trigger cell senescence or cell death, eventually causing tissue failure syndromes. Our data are consistent with these statements and suggest that the likelihood of similar processes occurring in normal individuals increases with age. Our work highlights the essential role of telomerase in the hematopoietic system and supports the notion that telomerase levels in hematopoietic cells, while limiting and unable to prevent overall telomere shortening, are nevertheless crucial to maintain telomere homeostasis with age. Human blood cells all originate from a common precursor, the hematopoietic stem cell. Telomerase, the enzyme responsible for adding telomere repeats to chromosome ends, is active in human hematopoietic stem cells but appears unable to maintain a constant telomere length with age. We first document the telomere length of different blood cell subsets from 835 healthy individuals between birth and 100 years, to delineate the normal rate of telomere attrition with age. Telomere lengths of blood cells were found to be slightly longer in women than in men, from birth and throughout life. We then compared this reference data to the telomere length in similar blood cell subsets from individuals with reduced telomerase activity as a result of a mutation in one of the genes encoding telomerase and from their direct relatives. Strikingly short telomeres were found in telomerase-deficient individuals, consistent with their cellular pathology and disease susceptibility, and somewhat shorter telomeres than expected were found in cells of relatives with normal telomerase maintenance. Our data can be used as a reference for blood cell telomere length in studies of normal and accelerated aging.
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Affiliation(s)
- Geraldine Aubert
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Gabriela M. Baerlocher
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Experimental Hematology, Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Irma Vulto
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Steven S. Poon
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Peter M. Lansdorp
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Division of Hematology, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
- * E-mail: ;
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Sheng X, Zhang L, Luo D, Tong N, Wang M, Fang Y, Li J, Zhang Z. A common variant nearTERCand telomere length are associated with susceptibility to childhood acute lymphoblastic leukemia in Chinese. Leuk Lymphoma 2012; 53:1688-92. [DOI: 10.3109/10428194.2012.671482] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Zimbone M, Bonaventura G, Baeri P, Barcellona ML. Unusual salt-induced behaviour of guanine-rich natural DNA evidenced by dynamic light scattering. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:425-36. [PMID: 22350081 DOI: 10.1007/s00249-012-0795-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 01/05/2012] [Accepted: 01/13/2012] [Indexed: 01/28/2023]
Abstract
The appearance of the slow mode, revealed by dynamic light scattering (DLS) measurements in Micrococcus luteus DNA with high GC content, and the effect of guanine sequences on changes of DNA physical state and conformational transitions were investigated. We used two different spectroscopic approaches: DLS, to evidence the relatively slowly diffusing particles arising at high salt concentration, ascribable to the formation of large unspecific molecular aggregates, and circular dichroism spectroscopy, to identify these entities. Our results bring us to conclude that a peculiar, unconventional, structural transition, due to the presence of long guanine stretches, in a well-defined experimental condition, can occur. We comment on the biological implications to detect, by spectroscopic measurements, such an unusual structure involved in the stability, protection and replication maintenance along the human telomeric G-rich strand.
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Affiliation(s)
- Massimo Zimbone
- Dipartimento di Fisica e Astronomia, Università di Catania, Catania, Italy.
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Affiliation(s)
- Pat Monaghan
- Institute of Biodiversity, Animal Health and Comparative Medicine Graham Kerr Building, University of Glasgow Glasgow G12 8QQ.
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Touzot F, Gaillard L, Vasquez N, Le Guen T, Bertrand Y, Bourhis J, Leblanc T, Fischer A, Soulier J, de Villartay JP, Revy P. Heterogeneous telomere defects in patients with severe forms of dyskeratosis congenita. J Allergy Clin Immunol 2012; 129:473-82, 482.e1-3. [DOI: 10.1016/j.jaci.2011.09.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/14/2011] [Accepted: 09/22/2011] [Indexed: 10/15/2022]
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50
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Stewart JA, Chaiken MF, Wang F, Price CM. Maintaining the end: roles of telomere proteins in end-protection, telomere replication and length regulation. Mutat Res 2012; 730:12-9. [PMID: 21945241 PMCID: PMC3256267 DOI: 10.1016/j.mrfmmm.2011.08.011] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 08/15/2011] [Accepted: 08/17/2011] [Indexed: 11/16/2022]
Abstract
Chromosome end protection is essential to protect genome integrity. Telomeres, tracts of repetitive DNA sequence and associated proteins located at the chromosomal terminus, serve to safeguard the ends from degradation and unwanted double strand break repair. Due to the essential nature of telomeres in protecting the genome, a number of unique proteins have evolved to ensure that telomere length and structure are preserved. The inability to properly maintain telomeres can lead to diseases such as dyskeratosis congenita, pulmonary fibrosis and cancer. In this review, we will discuss the known functions of mammalian telomere-associated proteins, their role in telomere replication and length regulation and how these processes relate to genome instability and human disease.
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Affiliation(s)
- Jason A. Stewart
- Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, Ohio 45267, USA
| | - Mary F. Chaiken
- Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, Ohio 45267, USA
| | - Feng Wang
- Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, Ohio 45267, USA
| | - Carolyn M. Price
- Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, Ohio 45267, USA
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