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Li B. Unwrap RAP1's Mystery at Kinetoplastid Telomeres. Biomolecules 2024; 14:67. [PMID: 38254667 PMCID: PMC10813129 DOI: 10.3390/biom14010067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 12/27/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024] Open
Abstract
Although located at the chromosome end, telomeres are an essential chromosome component that helps maintain genome integrity and chromosome stability from protozoa to mammals. The role of telomere proteins in chromosome end protection is conserved, where they suppress various DNA damage response machineries and block nucleolytic degradation of the natural chromosome ends, although the detailed underlying mechanisms are not identical. In addition, the specialized telomere structure exerts a repressive epigenetic effect on expression of genes located at subtelomeres in a number of eukaryotic organisms. This so-called telomeric silencing also affects virulence of a number of microbial pathogens that undergo antigenic variation/phenotypic switching. Telomere proteins, particularly the RAP1 homologs, have been shown to be a key player for telomeric silencing. RAP1 homologs also suppress the expression of Telomere Repeat-containing RNA (TERRA), which is linked to their roles in telomere stability maintenance. The functions of RAP1s in suppressing telomere recombination are largely conserved from kinetoplastids to mammals. However, the underlying mechanisms of RAP1-mediated telomeric silencing have many species-specific features. In this review, I will focus on Trypanosoma brucei RAP1's functions in suppressing telomeric/subtelomeric DNA recombination and in the regulation of monoallelic expression of subtelomere-located major surface antigen genes. Common and unique mechanisms will be compared among RAP1 homologs, and their implications will be discussed.
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Affiliation(s)
- Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA;
- Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
- Center for RNA Science and Therapeutics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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2
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Tornesello ML, Cerasuolo A, Starita N, Amiranda S, Bonelli P, Tuccillo FM, Buonaguro FM, Buonaguro L, Tornesello AL. Reactivation of telomerase reverse transcriptase expression in cancer: the role of TERT promoter mutations. Front Cell Dev Biol 2023; 11:1286683. [PMID: 38033865 PMCID: PMC10684755 DOI: 10.3389/fcell.2023.1286683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 11/02/2023] [Indexed: 12/02/2023] Open
Abstract
Telomerase activity and telomere elongation are essential conditions for the unlimited proliferation of neoplastic cells. Point mutations in the core promoter region of the telomerase reverse transcriptase (TERT) gene have been found to occur at high frequencies in several tumour types and considered a primary cause of telomerase reactivation in cancer cells. These mutations promote TERT gene expression by multiple mechanisms, including the generation of novel binding sites for nuclear transcription factors, displacement of negative regulators from DNA G-quadruplexes, recruitment of epigenetic activators and disruption of long-range interactions between TERT locus and telomeres. Furthermore, TERT promoter mutations cooperate with TPP1 promoter nucleotide changes to lengthen telomeres and with mutated BRAF and FGFR3 oncoproteins to enhance oncogenic signalling in cancer cells. TERT promoter mutations have been recognized as an early marker of tumour development or a major indicator of poor outcome and reduced patients survival in several cancer types. In this review, we summarize recent findings on the role of TERT promoter mutations, telomerase expression and telomeres elongation in cancer development, their clinical significance and therapeutic opportunities.
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Affiliation(s)
- Maria Lina Tornesello
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Napoli, Italy
| | - Andrea Cerasuolo
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Napoli, Italy
| | - Noemy Starita
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Napoli, Italy
| | - Sara Amiranda
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Napoli, Italy
| | - Patrizia Bonelli
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Napoli, Italy
| | - Franca Maria Tuccillo
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Napoli, Italy
| | - Franco M. Buonaguro
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Napoli, Italy
| | - Luigi Buonaguro
- Innovative Immunological Models Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Napoli, Italy
| | - Anna Lucia Tornesello
- Innovative Immunological Models Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, Napoli, Italy
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3
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Kuan XY, Fauzi NSA, Ng KY, Bakhtiar A. Exploring the Causal Relationship Between Telomere Biology and Alzheimer's Disease. Mol Neurobiol 2023; 60:4169-4183. [PMID: 37046137 PMCID: PMC10293431 DOI: 10.1007/s12035-023-03337-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
Telomeres, also known as the "protective caps" of our chromosomes, shorten with each cell cycle due to the end replication problem. This process, termed telomere attrition, is associated with many age-related disorders, such as Alzheimer's disease (AD). Despite the numerous studies conducted in this field, the role of telomere attrition in the onset of the disease remains unclear. To investigate the causal relationship between short telomeres and AD, this review aims to highlight the primary factors that regulate telomere length and maintain its integrity, with an additional outlook on the role of oxidative stress, which is commonly associated with aging and molecular damage. Although some findings thus far might be contradictory, telomere attrition likely plays a crucial role in the progression of AD due to its close association with oxidative stress. The currently available treatments for AD are only symptomatic without affecting the progression of the disease. The components of telomere biology discussed in this paper have previously been studied as an alternative treatment option for several diseases and have exhibited promising in vitro and in vivo results. Hence, this should provide a basis for future research to develop a potential therapeutic strategy for AD. (Created with BioRender.com).
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Affiliation(s)
- Xi-Yuen Kuan
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia
| | - Nurul Syahira Ahmad Fauzi
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia
| | - Khuen Yen Ng
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia
| | - Athirah Bakhtiar
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia.
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4
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Pepke ML, Ringsby TH, Eisenberg DTA. The evolution of early-life telomere length, pace-of-life and telomere-chromosome length dynamics in birds. Mol Ecol 2023; 32:2898-2912. [PMID: 36847070 DOI: 10.1111/mec.16907] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 02/09/2023] [Accepted: 02/21/2023] [Indexed: 03/01/2023]
Abstract
Telomeres, the short DNA sequences that protect chromosome ends, are an ancient molecular structure, which is highly conserved across most eukaryotes. Species differ in their telomere lengths, but the causes of this variation are not well understood. Here, we demonstrate that mean early-life telomere length is an evolutionary labile trait across 57 bird species (representing 35 families in 12 orders) with the greatest trait diversity found among passerines. Among these species, telomeres are significantly shorter in fast-lived than in slow-lived species, suggesting that telomere length may have evolved to mediate trade-offs between physiological requirements underlying the diversity of pace-of-life strategies in birds. This association was attenuated when excluding studies that may include interstitial telomeres in the estimation of mean telomere length. Curiously, within some species, larger individual chromosome size predicts longer telomere lengths on that chromosome, leading to the hypothesis that telomere length also covaries with chromosome length across species. We show that longer mean chromosome length or genome size tends to be associated with longer mean early-life telomere length (measured across all chromosomes) within a phylogenetic framework constituting up to 31 bird species. These associations were strengthened when excluding highly influential outliers. However, sensitivity analyses suggested that they were susceptible to sample size effects and not robust to the exclusion of studies that may include interstitial telomeres. Combined, our analyses generalize patterns previously found within a few species and provide potential adaptive explanations for the 10-fold variation in telomere lengths observed among birds.
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Affiliation(s)
- Michael Le Pepke
- Department of Biology, Centre for Biodiversity Dynamics (CBD), Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Thor Harald Ringsby
- Department of Biology, Centre for Biodiversity Dynamics (CBD), Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Dan T A Eisenberg
- Department of Anthropology, University of Washington, Seattle, Washington, USA
- Centre for Studies in Demography and Ecology, University of Washington, Seattle, Washington, USA
- Department of Biology, University of Washington, Seattle, Washington, USA
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5
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Zhang X, Zhang C, Zhou D, Zhang T, Chen X, Ren J, He C, Meng F, Zhou Q, Yang Q, Dai C, Lin G, Zeng S, Leng L. Telomeres cooperate in zygotic genome activation by affecting DUX4/ Dux transcription. iScience 2023; 26:106158. [PMID: 36843839 PMCID: PMC9950522 DOI: 10.1016/j.isci.2023.106158] [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: 09/16/2022] [Revised: 11/03/2022] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
Zygotic genome activation (ZGA) is initiated once the genome chromatin state is organized in the newly formed zygote. Telomeres are specialized chromatin structures at the ends of chromosomes and are reset during early embryogenesis, while the details and significance of telomere changes in preimplantation embryos remain unclear. We demonstrated that the telomere length was shortened in the minor ZGA stage and significantly elongated in the major ZGA stage of human and mouse embryos. Expression of the ZGA pioneer factor DUX4/Dux was negatively correlated with the telomere length. ATAC sequencing data revealed that the chromatin accessibility peaks on the DUX4 promoter region (i.e., the subtelomere of chromosome 4q) were transiently augmented in human minor ZGA. Reduction of telomeric heterochromatin H3K9me3 in the telomeric region also synergistically activated DUX4 expression with p53 in human embryonic stem cells. We propose herein that telomeres regulate the expression of DUX4/Dux through chromatin remodeling and are thereby involved in ZGA.
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Affiliation(s)
- Xiaorui Zhang
- Hospital of Hunan Guangxiu, Hunan Normal University, Hunan 410001, China,Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China,Department of Reproductive Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi 710061, China
| | - Changquan Zhang
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Di Zhou
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China
| | - Tianlei Zhang
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China
| | - Xueqin Chen
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Jinlin Ren
- Hospital of Hunan Guangxiu, Hunan Normal University, Hunan 410001, China
| | - Caixia He
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China
| | - Fei Meng
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China
| | - Qinwei Zhou
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China
| | - Qiaohui Yang
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Congling Dai
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Ge Lin
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China,Corresponding author
| | - Sicong Zeng
- Hospital of Hunan Guangxiu, Hunan Normal University, Hunan 410001, China,Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China,Corresponding author
| | - Lizhi Leng
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China,Corresponding author
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6
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Zheng SY, Zhu L, Wu LY, Liu HR, Ma XP, Li Q, Wu MD, Wang WJ, Li J, Wu HG. Helicobacter pylori-positive chronic atrophic gastritis and cellular senescence. Helicobacter 2023; 28:e12944. [PMID: 36539375 DOI: 10.1111/hel.12944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/03/2022] [Accepted: 12/05/2022] [Indexed: 01/27/2023]
Abstract
BACKGROUND Chronic atrophic gastritis (CAG) is a pathological stage in the Correa's cascade, whereby Helicobacter pylori (H. pylori) infection is the primary cause. Cellular senescence is an inducing factor for cancer occurrence and cellular senescence is an obvious phenomenon in gastric mucosal tissues of H. pylori-positive CAG patients. METHODS In this review, we collated the information on cellular senescence and H. pylori-positive CAG. RESULTS At present, only a few studies have observed the effect of cellular senescence on precancerous lesions. In combination with the latest research, this review has collated the information on cellular senescence and H. pylori-positive CAG from four aspects- telomere shortening, DNA methylation, increased reacive oxygen species (ROS) production, and failure of autophagy. CONCLUSION This is expected to be helpful for exploring the relevant mechanisms underlying inflammatory cancerous transformation and formulating appropriate treatment strategies.
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Affiliation(s)
- Shi-Yu Zheng
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lu Zhu
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lu-Yi Wu
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Hui-Rong Liu
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Shanghai Research Institute of Acupuncture and Meridian, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xiao-Peng Ma
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Shanghai Research Institute of Acupuncture and Meridian, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Qi Li
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Meng-Die Wu
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Wen-Jia Wang
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jing Li
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Huan-Gan Wu
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Shanghai Research Institute of Acupuncture and Meridian, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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7
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Wang C, Alfano R, Reimann B, Hogervorst J, Bustamante M, De Vivo I, Plusquin M, Nawrot TS, Martens DS. Genetic regulation of newborn telomere length is mediated and modified by DNA methylation. Front Genet 2022; 13:934277. [PMID: 36267401 PMCID: PMC9576874 DOI: 10.3389/fgene.2022.934277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/06/2022] [Indexed: 11/23/2022] Open
Abstract
Telomere length at birth determines later life telomere length and potentially predicts ageing-related diseases. However, the genetic and epigenetic settings of telomere length in newborns have not been analyzed. In addition, no study yet has reported how the interplay between genetic variants and genome-wide cytosine methylation explains the variation in early-life telomere length. In this study based on 281 mother-newborn pairs from the ENVIRONAGE birth cohort, telomere length and whole-genome DNA methylation were assessed in cord blood and 26 candidate single nucleotide polymorphism related to ageing or telomere length were genotyped. We identified three genetic variants associated with cord blood telomere length and 57 cis methylation quantitative trait loci (cis-mQTLs) of which 22 mQTLs confirmed previous findings and 35 were newly identified. Five SNPs were found to have significant indirect effects on cord blood telomere length via the mediating CpGs. The association between rs911874 (SOD2) and newborn telomere length was modified by nearby DNA methylation indicated by a significant statistical interaction. Our results suggest that DNA methylation in cis might have a mediation or modification effect on the genetic difference in newborn telomere length. This novel approach warrants future follow-up studies that are needed to further confirm and extend these findings.
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Affiliation(s)
- Congrong Wang
- Centre for Environmental Sciences, Hasselt University, Hasselt, Belgium
| | - Rossella Alfano
- Centre for Environmental Sciences, Hasselt University, Hasselt, Belgium
| | - Brigitte Reimann
- Centre for Environmental Sciences, Hasselt University, Hasselt, Belgium
| | | | - Mariona Bustamante
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
- CIBER de Epidemiología y Salud Pública, Madrid, Spain
- Center for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Immaculata De Vivo
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, United States
- Program in Genetic Epidemiology and Statistical Genetics, Harvard School of Public Health, Boston, MA, United States
| | - Michelle Plusquin
- Centre for Environmental Sciences, Hasselt University, Hasselt, Belgium
| | - Tim S. Nawrot
- Centre for Environmental Sciences, Hasselt University, Hasselt, Belgium
- Department of Public Health and Primary Care, Leuven University, Leuven, Belgium
| | - Dries S. Martens
- Centre for Environmental Sciences, Hasselt University, Hasselt, Belgium
- *Correspondence: Dries S. Martens,
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8
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Lupatov AY, Yarygin KN. Telomeres and Telomerase in the Control of Stem Cells. Biomedicines 2022; 10:biomedicines10102335. [PMID: 36289597 PMCID: PMC9598777 DOI: 10.3390/biomedicines10102335] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 11/16/2022] Open
Abstract
Stem cells serve as a source of cellular material in embryogenesis and postnatal growth and regeneration. This requires significant proliferative potential ensured by sufficient telomere length. Telomere attrition in the stem cells and their niche cells can result in the exhaustion of the regenerative potential of high-turnover organs, causing or contributing to the onset of age-related diseases. In this review, stem cells are examined in the context of the current telomere-centric theory of cell aging, which assumes that telomere shortening depends not just on the number of cell doublings (mitotic clock) but also on the influence of various internal and external factors. The influence of the telomerase and telomere length on the functional activity of different stem cell types, as well as on their aging and prospects of use in cell therapy applications, is discussed.
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9
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Kroupa M, Tomasova K, Kavec M, Skrobanek P, Buchler T, Kumar R, Vodickova L, Vodicka P. TElomeric repeat-containing RNA (TERRA): Physiological functions and relevance in cancer. Front Oncol 2022; 12:913314. [PMID: 35982970 PMCID: PMC9380590 DOI: 10.3389/fonc.2022.913314] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
Telomeres are complex protective structures located at the ends of linear eukaryotic chromosomes. Their purpose is to prevent genomic instability. Research progress in telomere biology during the past decades has identified a network of telomeric transcripts of which the best-studied is TElomeric Repeat-containing RNA (TERRA). TERRA was shown to be important not only for the preservation of telomere homeostasis and genomic stability but also for the expression of hundreds of genes across the human genome. These findings added a new level of complexity to telomere biology. Herein we provide insights on the telomere transcriptome, its relevance for proper telomere function, and its implications in human pathology. We also discuss possible clinical opportunities of exosomal telomere transcripts detection as a biomarker in cancer precision medicine.
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Affiliation(s)
- Michal Kroupa
- Department of the Molecular Biology of Cancer, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Medicine and Biomedical Center in Pilsen, Charles University, Pilsen, Czechia
- *Correspondence: Michal Kroupa, ; Pavel Vodicka,
| | - Kristyna Tomasova
- Department of the Molecular Biology of Cancer, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Medicine and Biomedical Center in Pilsen, Charles University, Pilsen, Czechia
| | - Miriam Kavec
- Department of the Molecular Biology of Cancer, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
- Department of Oncology, First Faculty of Medicine, Charles University and Thomayer University Hospital, Prague, Czechia
| | - Pavel Skrobanek
- Department of Oncology, First Faculty of Medicine, Charles University and Thomayer University Hospital, Prague, Czechia
| | - Tomas Buchler
- Department of Oncology, First Faculty of Medicine, Charles University and Thomayer University Hospital, Prague, Czechia
| | - Rajiv Kumar
- Department of the Molecular Biology of Cancer, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
- Division of Molecular Genetic Epidemiology, German Cancer Research Center, Heidelberg, Germany
| | - Ludmila Vodickova
- Department of the Molecular Biology of Cancer, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Medicine and Biomedical Center in Pilsen, Charles University, Pilsen, Czechia
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czechia
| | - Pavel Vodicka
- Department of the Molecular Biology of Cancer, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
- Faculty of Medicine and Biomedical Center in Pilsen, Charles University, Pilsen, Czechia
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czechia
- *Correspondence: Michal Kroupa, ; Pavel Vodicka,
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10
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Emerging mechanisms of telomerase reactivation in cancer. Trends Cancer 2022; 8:632-641. [PMID: 35568649 PMCID: PMC7614490 DOI: 10.1016/j.trecan.2022.03.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/24/2022] [Accepted: 03/28/2022] [Indexed: 12/17/2022]
Abstract
Mutations in the promoter of human telomerase reverse transcriptase (hTERT) result in hyperactivation of hTERT. Notably, all mutations are G>A transitions, frequently found in a wide range of cancer types, and causally associated with cancer progression. Initially, the mutations were understood to reactivate hTERT by generating novel E26 transformation-specific (ETS) binding sites. Recent work reveals the role of DNA secondary structure G-quadruplexes, telomere binding factor(s), and chromatin looping in hTERT regulation. Here, we discuss these emerging findings in relation to the clinically significant promoter mutations to provide a broader understanding of the context-dependent outcomes that result in hTERT activation in normal and pathogenic conditions.
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11
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Genome-wide screens identify specific drivers of mutant hTERT promoters. Proc Natl Acad Sci U S A 2022; 119:2105171119. [PMID: 35027447 PMCID: PMC8784157 DOI: 10.1073/pnas.2105171119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2021] [Indexed: 12/31/2022] Open
Abstract
Mutations in hTERT promoter are seen in over 19% of human cancers, irrespective of the cancer type. Understanding the molecular players that regulate Mut-hTERT promoters may help the design of effective targeting strategies to inhibit telomerase reactivation specifically in cancer cells. Our work uses genome-wide functional screens to identify 30 specific regulators of Mut-hTERT promoters. These candidates identified from the screening serve as an excellent resource to understand how telomerase is reactivated and as targets for making inhibitors to telomerase, a key driver of cancer. Cancer-specific hTERT promoter mutations reported in 19% of cancers result in enhanced telomerase activity. Understanding the distinctions between transcriptional regulation of wild-type (WT) and mutant (Mut) hTERT promoters may open up avenues for development of inhibitors which specially block hTERT expression in cancer cells. To comprehensively identify physiological regulators of WT- or Mut-hTERT promoters, we generated several isogenic reporter cells driven by endogenous hTERT loci. Genome-wide CRISPR-Cas9 and small interfering RNA screens using these isogenic reporter lines identified specific regulators of Mut-hTERT promoters. We validate and characterize one of these hits, namely, MED12, a kinase subunit of mediator complex. We demonstrate that MED12 specifically drives expression of hTERT from the Mut-hTERT promoter by mediating long-range chromatin interaction between the proximal Mut-hTERT promoter and T-INT1 distal regulatory region 260 kb upstream. Several hits identified in our screens could serve as potential therapeutic targets, inhibition of which may specifically block Mut-hTERT promoter driven telomerase reactivation in cancers.
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12
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Lin J, Epel E. Stress and telomere shortening: Insights from cellular mechanisms. Ageing Res Rev 2022; 73:101507. [PMID: 34736994 PMCID: PMC8920518 DOI: 10.1016/j.arr.2021.101507] [Citation(s) in RCA: 117] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 10/08/2021] [Accepted: 10/21/2021] [Indexed: 12/14/2022]
Abstract
Short telomeres confer risk of degenerative diseases. Chronic psychological stress can lead to disease through many pathways, and research from in vitro studies to human longitudinal studies has pointed to stress-induced telomere damage as an important pathway. However, there has not been a comprehensive model to describe how changes in stress physiology and neuroendocrine pathways can lead to changes in telomere biology. Critically short telomeres or the collapse of the telomere structure caused by displacement of telomere binding protein complex shelterin elicit a DNA damage response and lead to senescence or apoptosis. In this narrative review, we summarize the key roles glucocorticoids, reactive oxygen species (ROS) and mitochondria, and inflammation play in mediating the relationship between psychological stress and telomere maintenance. We emphasis that these mediators are interconnected and reinforce each other in positive feedback loops. Telomere length has not been studied across the lifespan yet, but the initial setting point at birth appears to be the most influential point, as it sets the lifetime trajectory, and is influenced by stress. We describe two types of intergenerational stress effects on telomeres - prenatal stress effects on telomeres during fetal development, and 'telotype transmission" -the directly inherited transmission of short telomeres from parental germline. It is clear that the initial simplistic view of telomere length as a mitotic clock has evolved into a far more complex picture of both transgenerational telomere influences, and of interconnected molecular and cellular pathways and networks, as hallmarks of aging where telomere maintenance is a key player interacting with mitochondria. Further mechanistic investigations testing this comprehensive model of stress mediators shaping telomere biology and the telomere-mitochondrial nexus will lead to better understanding from cell to human lifespan aging, and could lead to anti-aging interventions.
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13
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Lee KH, Kim DY, Kim W. Regulation of Gene Expression by Telomere Position Effect. Int J Mol Sci 2021; 22:ijms222312807. [PMID: 34884608 PMCID: PMC8657463 DOI: 10.3390/ijms222312807] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 11/16/2022] Open
Abstract
Many diseases that involve malignant tumors in the elderly affect the quality of human life; therefore, the relationship between aging and pathogenesis in geriatric diseases must be under-stood to develop appropriate treatments for these diseases. Recent reports have shown that epigenetic regulation caused by changes in the local chromatin structure plays an essential role in aging. This review provides an overview of the roles of telomere shortening on genomic structural changes during an age-dependent shift in gene expression. Telomere shortening is one of the most prominent events that is involved in cellular aging and it affects global gene expression through genome rearrangement. This review provides novel insights into the roles of telomere shortening in disease-affected cells during pathogenesis and suggests novel therapeutic approaches.
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Affiliation(s)
- Kyung-Ha Lee
- Division of Cosmetic Science and Technology, Daegu Haany University, Gyeongsan 38610, Korea;
| | - Do-Yeon Kim
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
- Correspondence: (D.-Y.K.); (W.K.)
| | - Wanil Kim
- Department of Biochemistry, Department of Convergence Medical Science, Institute of Health Sciences, School of Medicine, Gyeongsang National University, Jinju 52727, Korea
- Correspondence: (D.-Y.K.); (W.K.)
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14
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Hu K, Ghandi M, Huang FW. Integrated evaluation of telomerase activation and telomere maintenance across cancer cell lines. eLife 2021; 10:e66198. [PMID: 34486523 PMCID: PMC8530513 DOI: 10.7554/elife.66198] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 08/27/2021] [Indexed: 12/12/2022] Open
Abstract
In cancer, telomere maintenance is critical for the development of replicative immortality. Using genome sequences from the Cancer Cell Line Encyclopedia and Genomics of Drug Sensitivity in Cancer Project, we calculated telomere content across 1299 cancer cell lines. We find that telomerase reverse transcriptase (TERT) expression correlates with telomere content in lung, central nervous system, and leukemia cell lines. Using CRISPR/Cas9 screening data, we show that lower telomeric content is associated with dependency of CST telomere maintenance genes. Increased dependencies of shelterin members are associated with wild-type TP53 status. Investigating the epigenetic regulation of TERT, we find widespread allele-specific expression in promoter-wildtype contexts. TERT promoter-mutant cell lines exhibit hypomethylation at PRC2-repressed regions, suggesting a cooperative global epigenetic state in the reactivation of telomerase. By incorporating telomere content with genomic features across comprehensively characterized cell lines, we provide further insights into the role of telomere regulation in cancer immortality.
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Affiliation(s)
- Kevin Hu
- Broad Institute of MIT and HarvardCambridgeUnited States
- Division of Hematology/Oncology, Department of Medicine; Bakar Computational Health Sciences Institute; Institute for Human Genetics; University of California, San FranciscoSan FranciscoUnited States
- Helen Diller Family Comprehensive Cancer CenterSan FranciscoUnited States
| | - Mahmoud Ghandi
- Broad Institute of MIT and HarvardCambridgeUnited States
| | - Franklin W Huang
- Broad Institute of MIT and HarvardCambridgeUnited States
- Division of Hematology/Oncology, Department of Medicine; Bakar Computational Health Sciences Institute; Institute for Human Genetics; University of California, San FranciscoSan FranciscoUnited States
- Helen Diller Family Comprehensive Cancer CenterSan FranciscoUnited States
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15
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Dos Santos GA, Viana NI, Pimenta R, de Camargo JA, T Reis S, Moreira Leite KR, Srougi M. Telomeric zinc-finger associated protein (TZAP) in cancer biology: friend or foe? MOLECULAR BIOLOGY RESEARCH COMMUNICATIONS 2021; 10:121-129. [PMID: 34476265 DOI: 10.22099/mbrc.2021.40106.1607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
Abstract
The new identified protein telomeric zinc-finger associated protein (TZAP) is a negative regulator of telomere length. Since telomere length and telomere maintenance mechanisms are essential to cancer progression, TZAP is considered a new player in cancer biology. Here we aimed to analyze TZAP using the Cancer Genome Atlas data in a Pan-Cancer approach. We gathering data from TCGA Pan-Cancer studies utilizing cBioPortal, GEPIA and UALCAN. In total we analyzed 33 types of cancer (n=9664) and their respective controls (n=711). TZAP is transcribed in all cancers but less than 5% of all tumors show any somatic changes. TZAP was downregulated in kidney chromophobe carcinoma, and upregulated in esophageal cancer, head and neck squamous cell carcinomas, kidney renal clear cell carcinoma and in liver hepatocellular carcinoma. Globally, TZAP expression is related to favorable prognosis, associated to better overall and disease-free survival. Looking to specific tumors, TZAP expression has a dual behavior. Its downregulation is associated with poor prognosis in cervical squamous cell carcinoma, in kidney renal clear cell carcinoma, kidney papillary cell carcinoma, lung adenocarcinoma and pancreas adenocarcinoma. On the contrary, in adrenocortical carcinoma, colon and rectal cancer, brain lower grade glioma and prostate adenocarcinoma the upregulation of TZAP is related with poor prognosis. TZAP expression has a positive correlation with TRF1 and TRF2 in normal tissue but not in cancer. Our analyses indicate that TZAP has an important role in oncology and may be considered as a potential biomarker.
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Affiliation(s)
- Gabriel Arantes Dos Santos
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.,D'Or Institute for Research and Education (IDOR), Sao Paulo, Brazil
| | - Nayara Izabel Viana
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.,Minas Gerais State University (UEMG), Passos, Minas Gerais, Brazil
| | - Ruan Pimenta
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.,D'Or Institute for Research and Education (IDOR), Sao Paulo, Brazil
| | - Juliana Alves de Camargo
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
| | - Sabrina T Reis
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.,Minas Gerais State University (UEMG), Passos, Minas Gerais, Brazil.,Athens University Center (UniAtenas), Passos, Minas Gerais, Brazil
| | - Katia Ramos Moreira Leite
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
| | - Miguel Srougi
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.,D'Or Institute for Research and Education (IDOR), Sao Paulo, Brazil
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16
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Bühring J, Hecker M, Fitzner B, Zettl UK. Systematic Review of Studies on Telomere Length in Patients with Multiple Sclerosis. Aging Dis 2021; 12:1272-1286. [PMID: 34341708 PMCID: PMC8279528 DOI: 10.14336/ad.2021.0106] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/06/2021] [Indexed: 12/19/2022] Open
Abstract
Telomeres are protective cap structures at the end of chromosomes that are essential for maintaining genomic stability. Accelerated telomere shortening is related to premature cellular senescence. Shortened telomere lengths (TL) have been implicated in the pathogenesis of various chronic immune-mediated and neurological diseases. We aimed to systematically review the current literature on the association of TL as a measure of biological age and multiple sclerosis (MS). A comprehensive literature search was conducted to identify original studies that presented data on TL in samples from persons with MS. Quantitative and qualitative information was extracted from the articles to summarize and compare the studies. A total of 51 articles were screened, and 7 of them were included in this review. In 6 studies, average TL were analyzed in peripheral blood cells, whereas in one study, bone marrow-derived cells were used. Four of the studies reported significantly shorter leukocyte TL in at least one MS subtype in comparison to healthy controls (p=0.003 in meta-analysis). Shorter telomeres in patients with MS were found to be associated, independently of age, with greater disability, lower brain volume, increased relapse rate and more rapid conversion from relapsing to progressive MS. However, it remains unclear how telomere attrition in MS may be linked to oxidative stress, inflammation and age-related disease processes. Despite few studies in this field, there is substantial evidence on the association of TL and MS. Variability in TL appears to reflect heterogeneity in clinical presentation and course. Further investigations in large and well-characterized cohorts are warranted. More detailed studies on TL of individual chromosomes in specific cell types may help to gain new insights into the pathomechanisms of MS.
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Affiliation(s)
| | - Michael Hecker
- Correspondence should be addressed to: Dr. Michael Hecker, Rostock University Medical Center, Department of Neurology, Division of Neuroimmunology, Rostock, Germany. .
| | - Brit Fitzner
- Rostock University Medical Center, Department of Neurology, Division of Neuroimmunology, Rostock, Germany
| | - Uwe Klaus Zettl
- Rostock University Medical Center, Department of Neurology, Division of Neuroimmunology, Rostock, Germany
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17
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Marasco V, Boner W, Griffiths K, Heidinger B, Monaghan P. Repeated exposure to challenging environmental conditions influences telomere dynamics across adult life as predicted by changes in mortality risk. FASEB J 2021; 35:e21743. [PMID: 34192361 DOI: 10.1096/fj.202100556r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/27/2021] [Accepted: 06/07/2021] [Indexed: 12/15/2022]
Abstract
The effects of stress exposure are likely to vary depending on life-stage and stressor. While it has been postulated that mild stress exposure may have beneficial effects, the duration of such effects and the underlying mechanisms are unclear. While the long-term effects of early-life stress are relatively well studied, we know much less about the effects of exposure in adulthood since the early- and adult-life environments are often similar. We previously reported that repeated experimental exposure to a relatively mild stressor in female zebra finches, first experienced in young adulthood, initially had no effect on mortality risk, reduced mortality in middle age, but the apparently beneficial effects disappeared in old age. We show here that this is underpinned by differences between the control and stress-exposed group in the pattern of telomere change, with stress-exposed birds showing reduced telomere loss in middle adulthood. We thereby provide novel experimental evidence that telomere dynamics play a key role linking stress resilience and aging.
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Affiliation(s)
- Valeria Marasco
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Vienna, Austria
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Winnie Boner
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Kate Griffiths
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Britt Heidinger
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
- Biological Sciences Department, North Dakota State University, Fargo, ND, USA
| | - Pat Monaghan
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
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18
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Udroiu I, Sgura A. Growing and aging of hematopoietic stem cells. World J Stem Cells 2021; 13:594-604. [PMID: 34249229 PMCID: PMC8246248 DOI: 10.4252/wjsc.v13.i6.594] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/22/2020] [Accepted: 02/02/2021] [Indexed: 02/06/2023] Open
Abstract
In the hematopoietic system, a small number of stem cells produce a progeny of several distinct lineages. During ontogeny, they arise in the aorta-gonad-mesonephros region of the embryo and the placenta, afterwards colonise the liver and finally the bone marrow. After this fetal phase of rapid expansion, the number of hematopoietic stem cells continues to grow, in order to sustain the increasing blood volume of the developing newborn, and eventually reaches a steady-state. The kinetics of this growth are mirrored by the rates of telomere shortening in leukocytes. During adulthood, hematopoietic stem cells undergo a very small number of cell divisions. Nonetheless, they are subjected to aging, eventually reducing their potential to produce differentiated progeny. The causal relationships between telomere shortening, DNA damage, epigenetic changes, and aging have still to be elucidated.
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Affiliation(s)
- Ion Udroiu
- Department of Science, Roma Tre University, Rome 00146, Italy
| | - Antonella Sgura
- Department of Science, Roma Tre University, Rome 00146, Italy
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19
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Dong X, Sun S, Zhang L, Kim S, Tu Z, Montagna C, Maslov AY, Suh Y, Wang T, Campisi J, Vijg J. Age-related telomere attrition causes aberrant gene expression in sub-telomeric regions. Aging Cell 2021; 20:e13357. [PMID: 34018656 PMCID: PMC8208793 DOI: 10.1111/acel.13357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 03/01/2021] [Accepted: 03/07/2021] [Indexed: 12/13/2022] Open
Abstract
Telomere attrition has been proposed as a biomarker and causal factor in aging. In addition to causing cellular senescence and apoptosis, telomere shortening has been found to affect gene expression in subtelomeric regions. Here, we analyzed the distribution of age-related differentially expressed genes from the GTEx RNA sequencing database of 54 tissue types from 979 human subjects and found significantly more upregulated than downregulated genes in subtelomeric regions as compared to the genome-wide average. Our data demonstrate spatial relationships between telomeres and gene expression in aging.
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Affiliation(s)
- Xiao Dong
- Department of GeneticsAlbert Einstein College of MedicineBronxNYUSA
- Institute on the Biology of Aging and MetabolismDepartment of Genetics, Cell Biology and DevelopmentUniversity of MinnesotaMinneapolisMNUSA
| | - Shixiang Sun
- Department of GeneticsAlbert Einstein College of MedicineBronxNYUSA
| | - Lei Zhang
- Department of GeneticsAlbert Einstein College of MedicineBronxNYUSA
- Institute on the Biology of Aging and MetabolismDepartment of Genetics, Cell Biology and DevelopmentUniversity of MinnesotaMinneapolisMNUSA
| | - Seungsoo Kim
- Department of Obstetrics and GynecologyColumbia University Irving Medical CenterNew YorkNYUSA
| | - Zhidong Tu
- Department of Genetics and Genomic SciencesIcahn Institute for Genomics and Multiscale BiologyIcahn School of Medicine Mount SinaiNew YorkNYUSA
| | | | - Alexander Y. Maslov
- Department of GeneticsAlbert Einstein College of MedicineBronxNYUSA
- Laboratory of Applied Genomic TechnologiesVoronezh State University of Engineering TechnologyVoronezhRussia
| | - Yousin Suh
- Department of Obstetrics and GynecologyColumbia University Irving Medical CenterNew YorkNYUSA
- Department of Genetics and DevelopmentColumbia University Irving Medical CenterNew YorkNYUSA
| | - Tao Wang
- Department of Epidemiology & Population HealthAlbert Einstein College of MedicineBronxNYUSA
| | | | - Jan Vijg
- Department of GeneticsAlbert Einstein College of MedicineBronxNYUSA
- School of Public HealthCenter for Single‐Cell OmicsShanghai Jiao Tong University School of MedicineShanghaiChina
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20
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Arantes Dos Santos G, Viana NI, Pimenta R, Reis ST, Ramos Moreira Leite K, Srougi M. Hypothesis: The triad androgen receptor, zinc finger proteins and telomeres modulates the global gene expression pattern during prostate cancer progression. Med Hypotheses 2021; 150:110566. [PMID: 33799157 DOI: 10.1016/j.mehy.2021.110566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/19/2021] [Accepted: 03/09/2021] [Indexed: 01/11/2023]
Abstract
Currently, the biggest challenge for prostate cancer (PCa) is to understand the mechanism by which the disease acquires the castration-resistant phenotype and progresses to a fatal disease. PCa has a high genetic heterogeneity, and cannot be separated into well-defined molecular subtypes. Despite this, there is consensus about the role of the androgen receptor (AR) in all stages of the disease, including the transition to the castration-resistant phenotype. Since AR is a transcription factor, we investigated the possibility of PCa presenting a pattern of global gene expression during disease progression. By analyzing the TCGA and CCLE datasets, we were able to find a pattern of waves of genes being expressed during each stage of disease progression. This phenomenon suggests the existence of a mechanism that globally regulates gene expression, being AR, telomeres, and zinc finger proteins (ZNF), three important players. The AR modulates the telomere biology, and its transcription is regulated by ZNF. Recently, a study suggested that the telomere length might influence the expression of ZNF. Thus, we hypothesized that changes in the triad AR, telomeres, and ZNF control gene expression during the progression of PCa.
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Affiliation(s)
- Gabriel Arantes Dos Santos
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil; D'Or Institute for Research and Education (IDOR), Sao Paulo, SP, Brazil.
| | - Nayara Izabel Viana
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
| | - Ruan Pimenta
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil; D'Or Institute for Research and Education (IDOR), Sao Paulo, SP, Brazil
| | - Sabrina T Reis
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil; Athens University Center (UniAtenas), Passos, MG, Brazil; Minas Gerais State University (UEMG), Passos, MG, Brazil
| | - Katia Ramos Moreira Leite
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
| | - Miguel Srougi
- Urology Department, Laboratory of Medical Investigation (LIM55), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil; D'Or Institute for Research and Education (IDOR), Sao Paulo, SP, Brazil
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21
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Dogan F, Forsyth NR. Telomerase Regulation: A Role for Epigenetics. Cancers (Basel) 2021; 13:cancers13061213. [PMID: 33802026 PMCID: PMC8000866 DOI: 10.3390/cancers13061213] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/05/2021] [Accepted: 03/07/2021] [Indexed: 12/11/2022] Open
Abstract
Simple Summary Maintenance of telomeres is a fundamental step in human carcinogenesis and is primarily regulated by telomerase and the human telomerase reverse transcriptase gene (TERT). Improved understanding of the transcriptional control of this gene may provide potential therapeutic targets. Epigenetic modifications are a prominent mechanism to control telomerase activity and regulation of the TERT gene. TERT-targeting miRNAs have been widely studied and their function explained through pre-clinical in vivo model-based validation studies. Further, histone deacetylase inhibitors are now in pre and early clinical trials with significant clinical success. Importantly, TERT downregulation through epigenetic modifications including TERT promoter methylation, histone deacetylase inhibitors, and miRNA activity might contribute to clinical study design. This review provides an overview of the epigenetic mechanisms involved in the regulation of TERT expression and telomerase activity. Abstract Telomerase was first described by Greider and Blackburn in 1984, a discovery ultimately recognized by the Nobel Prize committee in 2009. The three decades following on from its discovery have been accompanied by an increased understanding of the fundamental mechanisms of telomerase activity, and its role in telomere biology. Telomerase has a clearly defined role in telomere length maintenance and an established influence on DNA replication, differentiation, survival, development, apoptosis, tumorigenesis, and a further role in therapeutic resistance in human stem and cancer cells including those of breast and cervical origin. TERT encodes the catalytic subunit and rate-limiting factor for telomerase enzyme activity. The mechanisms of activation or silencing of TERT remain open to debate across somatic, cancer, and stem cells. Promoter mutations upstream of TERT may promote dysregulated telomerase activation in tumour cells but additional factors including epigenetic, transcriptional and posttranscriptional modifications also have a role to play. Previous systematic analysis indicated methylation and mutation of the TERT promoter in 53% and 31%, respectively, of TERT expressing cancer cell lines supporting the concept of a key role for epigenetic alteration associated with TERT dysregulation and cellular transformation. Epigenetic regulators including DNA methylation, histone modification, and non-coding RNAs are now emerging as drivers in the regulation of telomeres and telomerase activity. Epigenetic regulation may be responsible for reversible silencing of TERT in several biological processes including development and differentiation, and increased TERT expression in cancers. Understanding the epigenetic mechanisms behind telomerase regulation holds important prospects for cancer treatment, diagnosis and prognosis. This review will focus on the role of epigenetics in telomerase regulation.
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Affiliation(s)
- Fatma Dogan
- The Guy Hilton Research Laboratories, School of Pharmacy and Bioengineering, Faculty of Medicine and Health Sciences, Keele University, Stoke on Trent ST4 7QB, UK;
| | - Nicholas R. Forsyth
- The Guy Hilton Research Laboratories, School of Pharmacy and Bioengineering, Faculty of Medicine and Health Sciences, Keele University, Stoke on Trent ST4 7QB, UK;
- School of Medicine, Tongji University, Shanghai 200092, China
- Correspondence:
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22
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Campion CG, Verissimo T, Cossette S, Tremblay J. Does Subtelomeric Position of COMMD5 Influence Cancer Progression? Front Oncol 2021; 11:642130. [PMID: 33768002 PMCID: PMC7985453 DOI: 10.3389/fonc.2021.642130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/01/2021] [Indexed: 01/04/2023] Open
Abstract
The COMMD proteins are a family of ten pleiotropic factors which are widely conserved throughout evolution and are involved in the regulation of many cellular and physiological processes. COMMD proteins are mainly expressed in adult tissue and their downregulation has been correlated with tumor progression and poor prognosis in cancer. Among this family, COMMD5 emerged as a versatile modulator of tumor progression. Its expression can range from being downregulated to highly up regulated in a variety of cancer types. Accordingly, two opposing functions could be proposed for COMMD5 in cancer. Our studies supported a role for COMMD5 in the establishment and maintenance of the epithelial cell phenotype, suggesting a tumor suppressor function. However, genetic alterations leading to amplification of COMMD5 proteins have also been observed in various types of cancer, suggesting an oncogenic function. Interestingly, COMMD5 is the only member of this family that is located at the extreme end of chromosome 8, near its telomere. Here, we review some data concerning expression and role of COMMD5 and propose a novel rationale for the potential link between the subtelomeric position of COMMD5 on chromosome 8 and its contrasting functions in cancer.
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Affiliation(s)
- Carole G Campion
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Thomas Verissimo
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Suzanne Cossette
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Johanne Tremblay
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Département de Médecine, Université de Montréal, Montréal, QC, Canada
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23
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Zhang N, Li Y, Lai TP, Shay JW, Danuser G. Imaging assay to probe the role of telomere length shortening on telomere-gene interactions in single cells. Chromosoma 2021; 130:61-73. [PMID: 33555479 PMCID: PMC7889534 DOI: 10.1007/s00412-020-00747-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/23/2020] [Accepted: 11/30/2020] [Indexed: 12/20/2022]
Abstract
Telomeres are repetitive non-coding nucleotide sequences (TTAGGGn) capping the ends of chromosomes. Progressive telomere shortening with increasing age has been associated with shifts in gene expression through models such as the telomere position effect (TPE), which suggests reduced interference of the telomere with transcriptional activity of increasingly more distant genes. A modification of the TPE model, referred to as Telomere Position Effects over Long Distance (TPE-OLD), explains why some genes 1-10 MB from a telomere are still affected by TPE, but genes closer to the telomere are not. Here, we describe an imaging approach to systematically examine the occurrence of TPE-OLD at the single cell level. Compared to existing methods, the pipeline allows rapid analysis of hundreds to thousands of cells, which is necessary to establish TPE-OLD as an acceptable mechanism of gene expression regulation. We examined two human genes, ISG15 and TERT, for which TPE-OLD has been described before. For both genes, we found less interaction with the telomere on the same chromosome in old cells compared to young cells; and experimentally elongated telomeres in old cells rescued the level of telomere interaction for both genes. However, the dependency of the interactions on the age progression from young to old cells varied. One model for the differences between ISG15 and TERT may relate to the markedly distinct interstitial telomeric sequence arrangement in the two genes. Overall, this provides a strong rationale for the role of telomere length shortening in the regulation of gene expression.
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Affiliation(s)
- Ning Zhang
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yanhui Li
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Tsung-Po Lai
- Center of Human Development and Aging, Rutgers New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Jerry W Shay
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA.
| | - Gaudenz Danuser
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA.
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA.
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24
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Hecker M, Fitzner B, Jäger K, Bühring J, Schwartz M, Hartmann A, Walter M, Zettl UK. Leukocyte Telomere Length in Patients with Multiple Sclerosis and Its Association with Clinical Phenotypes. Mol Neurobiol 2021; 58:2886-2896. [PMID: 33547621 PMCID: PMC8128833 DOI: 10.1007/s12035-021-02315-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 01/26/2021] [Indexed: 12/16/2022]
Abstract
Aging is a significant factor influencing the course of multiple sclerosis (MS). Accelerated telomere attrition is an indicator of premature biological aging and a potential contributor to various chronic diseases, including neurological disorders. However, there is currently a lack of studies focusing on telomere lengths in patients with MS. We measured the average leukocyte telomere length (LTL) in biobanked DNA samples of 40 relapsing-remitting MS patients (RRMS), 20 primary progressive MS patients (PPMS), and 60 healthy controls using a multiplex quantitative polymerase chain reaction method. Changes in LTL over a period of >10 years were evaluated in a subset of 10 patients. Association analyses of baseline LTL with the long-term clinical profiles of the patients were performed using inferential statistical tests and regression models adjusted for age and sex. The cross-sectional analysis revealed that the RRMS group was characterized by a significantly shorter relative LTL, on average, as compared to the PPMS group and controls. Shorter telomeres at baseline were also associated with a higher conversion rate from RRMS to secondary progressive MS (SPMS) in the 10-year follow-up. The LTL decrease over time was similar in RRMS patients and PPMS patients in the longitudinal analysis. Our data suggest a possible contributory role of accelerated telomere shortening in the pathobiology of MS. The interplay between disease-related immune system alterations, immunosenescence, and telomere dynamics deserves further investigation. New insights into the mechanisms of disease might be obtained, e.g., by exploring the distribution of telomere lengths in specific blood cell populations.
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Affiliation(s)
- Michael Hecker
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Str. 20, 18147, Rostock, Germany.
| | - Brit Fitzner
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Str. 20, 18147, Rostock, Germany
| | - Kathrin Jäger
- Institute for Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057, Rostock, Germany.,Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Jan Bühring
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Str. 20, 18147, Rostock, Germany
| | - Margit Schwartz
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Str. 20, 18147, Rostock, Germany
| | - Alexander Hartmann
- Institute for Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057, Rostock, Germany
| | - Michael Walter
- Institute for Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, Ernst-Heydemann-Str. 6, 18057, Rostock, Germany.
| | - Uwe Klaus Zettl
- Division of Neuroimmunology, Department of Neurology, Rostock University Medical Center, Gehlsheimer Str. 20, 18147, Rostock, Germany
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25
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Santos AP, Gaudin V, Mozgová I, Pontvianne F, Schubert D, Tek AL, Dvořáčková M, Liu C, Fransz P, Rosa S, Farrona S. Tidying-up the plant nuclear space: domains, functions, and dynamics. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5160-5178. [PMID: 32556244 PMCID: PMC8604271 DOI: 10.1093/jxb/eraa282] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/12/2020] [Indexed: 05/07/2023]
Abstract
Understanding how the packaging of chromatin in the nucleus is regulated and organized to guide complex cellular and developmental programmes, as well as responses to environmental cues is a major question in biology. Technological advances have allowed remarkable progress within this field over the last years. However, we still know very little about how the 3D genome organization within the cell nucleus contributes to the regulation of gene expression. The nuclear space is compartmentalized in several domains such as the nucleolus, chromocentres, telomeres, protein bodies, and the nuclear periphery without the presence of a membrane around these domains. The role of these domains and their possible impact on nuclear activities is currently under intense investigation. In this review, we discuss new data from research in plants that clarify functional links between the organization of different nuclear domains and plant genome function with an emphasis on the potential of this organization for gene regulation.
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Affiliation(s)
- Ana Paula Santos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova
de Lisboa, Oeiras, Portugal
| | - Valérie Gaudin
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université
Paris-Saclay, Versailles, France
| | - Iva Mozgová
- Biology Centre of the Czech Academy of Sciences, České
Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České
Budějovice, Czech Republic
| | - Frédéric Pontvianne
- CNRS, Laboratoire Génome et Développement des Plantes (LGDP), Université de
Perpignan Via Domitia, Perpignan, France
| | - Daniel Schubert
- Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Ahmet L Tek
- Agricultural Genetic Engineering Department, Niğde Ömer Halisdemir
University, Niğde, Turkey
| | | | - Chang Liu
- Center for Plant Molecular Biology (ZMBP), University of
Tübingen, Tübingen, Germany
- Institute of Biology, University of Hohenheim, Stuttgart,
Germany
| | - Paul Fransz
- University of Amsterdam, Amsterdam, The
Netherlands
| | - Stefanie Rosa
- Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sara Farrona
- Plant and AgriBiosciences Centre, Ryan Institute, NUI Galway,
Galway, Ireland
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26
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Vinayagamurthy S, Ganguly A, Chowdhury S. Extra-telomeric impact of telomeres: Emerging molecular connections in pluripotency or stemness. J Biol Chem 2020; 295:10245-10254. [PMID: 32444498 DOI: 10.1074/jbc.rev119.009710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 05/21/2020] [Indexed: 12/26/2022] Open
Abstract
Telomeres comprise specialized nucleic acid-protein complexes that help protect chromosome ends from DNA damage. Moreover, telomeres associate with subtelomeric regions through looping. This results in altered expression of subtelomeric genes. Recent observations further reveal telomere length-dependent gene regulation and epigenetic modifications at sites spread across the genome and distant from telomeres. This regulation is mediated through the telomere-binding protein telomeric repeat-binding factor 2 (TRF2). These observations suggest a role of telomeres in extra-telomeric functions. Most notably, telomeres have a broad impact on pluripotency and differentiation. For example, cardiomyocytes differentiate with higher efficacy from induced pluripotent stem cells having long telomeres, and differentiated cells obtained from human embryonic stem cells with relatively long telomeres have a longer lifespan. Here, we first highlight reports on these two seemingly distinct research areas: the extra-telomeric role of telomere-binding factors and the role of telomeres in pluripotency/stemness. On the basis of the observations reported in these studies, we draw attention to potential molecular connections between extra-telomeric biology and pluripotency. Finally, in the context of the nonlocal influence of telomeres on pluripotency and stemness, we discuss major opportunities for progress in molecular understanding of aging-related disorders and neurodegenerative diseases.
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Affiliation(s)
- Soujanya Vinayagamurthy
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR Institute of Genomics and Integrative Biology, New Delhi, India
| | - Akansha Ganguly
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi, India
| | - Shantanu Chowdhury
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi, India .,Academy of Scientific and Innovative Research (AcSIR), CSIR Institute of Genomics and Integrative Biology, New Delhi, India.,G.N.R. Knowledge Centre for Genome Informatics, CSIR Institute of Genomics and Integrative Biology, New Delhi, India
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27
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Garsuault D, Bouyer C, Nguyen E, Kandhari R, Prochazkova-Carlotti M, Chevret E, Forgez P, Ségal-Bendirdjian E. Complex context relationships between DNA methylation and accessibility, histone marks, and hTERT gene expression in acute promyelocytic leukemia cells: perspectives for all-trans retinoic acid in cancer therapy. Mol Oncol 2020; 14:1310-1326. [PMID: 32239597 PMCID: PMC7266276 DOI: 10.1002/1878-0261.12681] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/19/2020] [Accepted: 03/28/2020] [Indexed: 02/06/2023] Open
Abstract
Telomerase (hTERT) reactivation and sustained expression is a key event in the process of cellular transformation. Therefore, the identification of the mechanisms regulating hTERT expression is of great interest for the development of new anticancer therapies. Although the epigenetic state of hTERT gene promoter is important, we still lack a clear understanding of the mechanisms by which epigenetic changes affect hTERT expression. Retinoids are well-known inducers of granulocytic maturation in acute promyelocytic leukemia (APL). We have previously shown that retinoids repressed hTERT expression in the absence of maturation leading to growth arrest and cell death. Exploring the mechanisms of this repression, we showed that transcription factor binding was dependent on the epigenetic status of hTERT promoter. In the present study, we used APL cells lines and publicly available datasets from APL patients to further investigate the integrated epigenetic events that promote hTERT promoter transition from its silent to its active state, and inversely. We showed, in APL patients, that the methylation of the distal domain of hTERT core promoter was altered and correlated with the outcome of the disease. Further studies combining complementary approaches carried out on APL cell lines highlighted the significance of a domain outside the minimal promoter, localized around 5 kb upstream from the transcription start site, in activating hTERT. This domain is characterized by DNA hypomethylation and H3K4Me3 deposition. Our findings suggest a cooperative interplay between hTERT promoter methylation, chromatin accessibility, and histone modifications that force the revisiting of previously proposed concepts regarding hTERT epigenetic regulation. They represent, therefore, a major advance in predicting sensitivity to retinoid-induced hTERT repression and, more generally, in the potential development of therapies targeting hTERT expression in cancers.
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Affiliation(s)
- Delphine Garsuault
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France.,Paris-Sud University, Paris-Saclay University, Orsay, France
| | - Claire Bouyer
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France
| | - Eric Nguyen
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France
| | - Rohan Kandhari
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Indian Institute of Technology, BHU, Varanasi, India
| | | | - Edith Chevret
- Team Cutaneous Lymphoma Oncogenesis, INSERM U1053, Bordeaux, France
| | - Patricia Forgez
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France
| | - Evelyne Ségal-Bendirdjian
- Team: Cellular Homeostasis, Cancer, and Therapies, INSERM UMR-S 1124, Université de Paris, France.,Université de Paris, Paris Sorbonne Cité, France.,BioMedTech Facilities, CNRS UMS2009/INSERM US36, Université de Paris, France
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28
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Feng JX, Riddle NC. Epigenetics and genome stability. Mamm Genome 2020; 31:181-195. [PMID: 32296924 DOI: 10.1007/s00335-020-09836-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 04/07/2020] [Indexed: 12/19/2022]
Abstract
Maintaining genome stability is essential to an organism's health and survival. Breakdown of the mechanisms protecting the genome and the resulting genome instability are an important aspect of the aging process and have been linked to diseases such as cancer. Thus, a large network of interconnected pathways is responsible for ensuring genome integrity in the face of the continuous challenges that induce DNA damage. While these pathways are diverse, epigenetic mechanisms play a central role in many of them. DNA modifications, histone variants and modifications, chromatin structure, and non-coding RNAs all carry out a variety of functions to ensure that genome stability is maintained. Epigenetic mechanisms ensure the functions of centromeres and telomeres that are essential for genome stability. Epigenetic mechanisms also protect the genome from the invasion by transposable elements and contribute to various DNA repair pathways. In this review, we highlight the integral role of epigenetic mechanisms in the maintenance of genome stability and draw attention to issues in need of further study.
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Affiliation(s)
- Justina X Feng
- Department of Biology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nicole C Riddle
- Department of Biology, The University of Alabama at Birmingham, Birmingham, AL, USA.
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29
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Kwapisz M, Morillon A. Subtelomeric Transcription and its Regulation. J Mol Biol 2020; 432:4199-4219. [PMID: 32035903 PMCID: PMC7374410 DOI: 10.1016/j.jmb.2020.01.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 01/14/2020] [Accepted: 01/14/2020] [Indexed: 12/13/2022]
Abstract
The subtelomeres, highly heterogeneous repeated sequences neighboring telomeres, are transcribed into coding and noncoding RNAs in a variety of organisms. Telomereproximal subtelomeric regions produce non-coding transcripts i.e., ARRET, αARRET, subTERRA, and TERRA, which function in telomere maintenance. The role and molecular mechanisms of the majority of subtelomeric transcripts remain unknown. This review depicts the current knowledge and puts into perspective the results obtained in different models from yeasts to humans.
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Affiliation(s)
- Marta Kwapisz
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France
| | - Antonin Morillon
- ncRNA, Epigenetic and Genome Fluidity, CNRS UMR 3244, Sorbonne Université, PSL University, Institut Curie, Centre de Recherche, 26 rue d'Ulm, 75248, Paris, France.
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30
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WGS-based telomere length analysis in Dutch family trios implicates stronger maternal inheritance and a role for RRM1 gene. Sci Rep 2019; 9:18758. [PMID: 31822713 PMCID: PMC6904582 DOI: 10.1038/s41598-019-55109-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 11/24/2019] [Indexed: 12/14/2022] Open
Abstract
Telomere length (TL) regulation is an important factor in ageing, reproduction and cancer development. Genetic, hereditary and environmental factors regulating TL are currently widely investigated, however, their relative contribution to TL variability is still understudied. We have used whole genome sequencing data of 250 family trios from the Genome of the Netherlands project to perform computational measurement of TL and a series of regression and genome-wide association analyses to reveal TL inheritance patterns and associated genetic factors. Our results confirm that TL is a largely heritable trait, primarily with mother's, and, to a lesser extent, with father's TL having the strongest influence on the offspring. In this cohort, mother's, but not father's age at conception was positively linked to offspring TL. Age-related TL attrition of 40 bp/year had relatively small influence on TL variability. Finally, we have identified TL-associated variations in ribonuclease reductase catalytic subunit M1 (RRM1 gene), which is known to regulate telomere maintenance in yeast. We also highlight the importance of multivariate approach and the limitations of existing tools for the analysis of TL as a polygenic heritable quantitative trait.
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31
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Abstract
Stress exposure can leave long-term footprints within the organism, like in telomeres (TLs), protective chromosome caps that shorten during cell replication and following exposure to stressors. Short TLs are considered to indicate lower fitness prospects, but why TLs shorten under stressful conditions is not understood. Glucocorticoid hormones (GCs) increase upon stress exposure and are thought to promote TL shortening by increasing oxidative damage. However, evidence that GCs are pro-oxidants and oxidative stress is causally linked to TL attrition is mixed . Based on new biochemical findings, we propose the metabolic telomere attrition hypothesis: during times of substantially increased energy demands, TLs are shortened as part of the transition into an organismal 'emergency state', which prioritizes immediate survival functions over processes with longer-term benefits. TL attrition during energy shortages could serve multiple roles including amplified signalling of cellular energy debt to re-direct critical resources to immediately important processes. This new view of TL shortening as a strategy to resolve major energetic trade-offs can improve our understanding of TL dynamics. We suggest that TLs are master regulators of cell homeostasis and propose future research avenues to understand the interactions between energy homeostasis, metabolic regulators and TL.
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Affiliation(s)
- Stefania Casagrande
- 1 Research Group Evolutionary Physiology, Max Planck Institute for Ornithology , 82319 Seewiesen , Germany
| | - Michaela Hau
- 1 Research Group Evolutionary Physiology, Max Planck Institute for Ornithology , 82319 Seewiesen , Germany.,2 Department of Biology, University of Konstanz , D-78457 Konstanz , Germany
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32
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Nersisyan L, Hopp L, Loeffler-Wirth H, Galle J, Loeffler M, Arakelyan A, Binder H. Telomere Length Maintenance and Its Transcriptional Regulation in Lynch Syndrome and Sporadic Colorectal Carcinoma. Front Oncol 2019; 9:1172. [PMID: 31750255 PMCID: PMC6848383 DOI: 10.3389/fonc.2019.01172] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 10/18/2019] [Indexed: 12/14/2022] Open
Abstract
Background: Activation of telomere maintenance mechanisms (TMMs) is a hallmark of most cancers, and is required to prevent genome instability and to establish cellular immortality through reconstitution of capping of chromosome ends. TMM depends on the cancer type. Comparative studies linking tumor biology and TMM have potential impact for evaluating cancer onset and development. Methods: We have studied alterations of telomere length, their sequence composition and transcriptional regulation in mismatch repair deficient colorectal cancers arising in Lynch syndrome (LS-CRC) and microsatellite instable (MSI) sporadic CRC (MSI s-CRC), and for comparison, in microsatellite stable (MSS) s-CRC and in benign colon mucosa. Our study applied bioinformatics analysis of whole genome DNA and RNA sequencing data and a pathway model to study telomere length alterations and the potential effect of the "classical" telomerase (TEL-) and alternative (ALT-) TMM using transcriptomic signatures. Results: We have found progressive decrease of mean telomere length in all cancer subtypes compared with reference systems. Our results support the view that telomere attrition is an early event in tumorigenesis. TMM gets activated in all tumors studied due to concerted overexpression of a large fraction of genes with direct relation to telomere function, where only a very small fraction of them showed recurrent mutations. TEL-related transcriptional state was dominating in all CRC subtypes, showing, however, subtype-specific activation patterns; while contribution of the ALT-TMM was slightly more prominent in the hypermutated MSI s-CRC and LS-CRC. TEL-TMM is mainly activated by over-expression of DKC1 and/or TERT genes and their interaction partners, where DKC1 is more prominent in MSS than in MSI s-CRC and can serve as a transcriptomic marker of TMM activity. Conclusions: Our results suggest that transcriptional patterns are indicative for TMM pathway activation with subtle differences between TEL and ALT mechanisms in a CRC subtype-specific fashion. Sequencing data potentially provide a suited measure to study alterations of telomere length and of underlying transcriptional regulation. Further studies are needed to improve this method.
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Affiliation(s)
- Lilit Nersisyan
- Group of Bioinformatics, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia
| | - Lydia Hopp
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany
| | - Henry Loeffler-Wirth
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany
| | - Jörg Galle
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany
| | - Markus Loeffler
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany.,Institute for Medical Informatics, Statistics and Epidemiology, Leipzig University, Leipzig, Germany
| | - Arsen Arakelyan
- Group of Bioinformatics, Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia
| | - Hans Binder
- Interdisciplinary Centre for Bioinformatics, Leipzig University, Leipzig, Germany
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33
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Niewisch MR, Savage SA. An update on the biology and management of dyskeratosis congenita and related telomere biology disorders. Expert Rev Hematol 2019; 12:1037-1052. [PMID: 31478401 DOI: 10.1080/17474086.2019.1662720] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Introduction: Telomere biology disorders (TBDs) encompass a group of illnesses caused by germline mutations in genes regulating telomere maintenance, resulting in very short telomeres. Possible TBD manifestations range from complex multisystem disorders with onset in childhood such as dyskeratosis congenita (DC), Hoyeraal-Hreidarsson syndrome, Revesz syndrome and Coats plus to adults presenting with one or two DC-related features.Areas covered: The discovery of multiple genetic causes and inheritance patterns has led to the recognition of a spectrum of clinical features affecting multiple organ systems. Patients with DC and associated TBDs are at high risk of bone marrow failure, cancer, liver and pulmonary disease. Recently, vascular diseases, including pulmonary arteriovenous malformations and gastrointestinal telangiectasias, have been recognized as additional manifestations. Diagnostics include detection of very short leukocyte telomeres and germline genetic testing. Hematopoietic cell transplantation and lung transplantation are the only current therapeutic modalities but are complicated by numerous comorbidities. This review summarizes the pathophysiology underlying TBDs, associated clinical features, management recommendations and therapeutic options.Expert opinion: Understanding TBDs as complex, multisystem disorders with a heterogenous genetic background and diverse phenotypes, highlights the importance of clinical surveillance and the urgent need to develop new therapeutic strategies to improve health outcomes.
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Affiliation(s)
- Marena R Niewisch
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sharon A Savage
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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Abstract
Many recent advances have emerged in the telomere and telomerase fields. This Timeline article highlights the key advances that have expanded our views on the mechanistic underpinnings of telomeres and telomerase and their roles in ageing and disease. Three decades ago, the classic view was that telomeres protected the natural ends of linear chromosomes and that telomerase was a specific telomere-terminal transferase necessary for the replication of chromosome ends in single-celled organisms. While this concept is still correct, many diverse fields associated with telomeres and telomerase have substantially matured. These areas include the discovery of most of the key molecular components of telomerase, implications for limits to cellular replication, identification and characterization of human genetic disorders that result in premature telomere shortening, the concept that inhibiting telomerase might be a successful therapeutic strategy and roles for telomeres in regulating gene expression. We discuss progress in these areas and conclude with challenges and unanswered questions in the field.
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Affiliation(s)
- Jerry W Shay
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA.
| | - Woodring E Wright
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
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35
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Debnath A, Rodriguez MA, Ankri S. Editorial: Recent Progresses in Amebiasis. Front Cell Infect Microbiol 2019; 9:247. [PMID: 31338336 PMCID: PMC6629773 DOI: 10.3389/fcimb.2019.00247] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 06/25/2019] [Indexed: 12/27/2022] Open
Affiliation(s)
- Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Mario Alberto Rodriguez
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | - Serge Ankri
- Department of Molecular Microbiology, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
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36
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Abstract
Telomeres are specialised structures at the end of linear chromosomes. They consist of tandem repeats of the hexanucleotide sequence TTAGGG, as well as a protein complex called shelterin. Together, they form a protective loop structure against chromosome fusion and degradation. Shortening or damage to telomeres and opening of the loop induce an uncapped state that triggers a DNA damage response resulting in senescence or apoptosis.Average telomere length, usually measured in human blood lymphocytes, was thought to be a biomarker for ageing, survival and mortality. However, it becomes obvious that regulation of telomere length is very complex and involves multiple processes. For example, the "end replication problem" during DNA replication as well as oxidative stress are responsible for the shortening of telomeres. In contrast, telomerase activity can potentially counteract telomere shortening when it is able to access and interact with telomeres. However, while highly active during development and in cancer cells, the enzyme is down-regulated in most human somatic cells with a few exceptions such as human lymphocytes. In addition, telomeres can be transcribed, and the transcription products called TERRA are involved in telomere length regulation.Thus, telomere length and their integrity are regulated at many different levels, and we only start to understand this process under conditions of increased oxidative stress, inflammation and during diseases as well as the ageing process.This chapter aims to describe our current state of knowledge on telomeres and telomerase and their regulation in order to better understand their role for the ageing process.
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37
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Fathi E, Charoudeh HN, Sanaat Z, Farahzadi R. Telomere shortening as a hallmark of stem cell senescence. Stem Cell Investig 2019; 6:7. [PMID: 31019963 DOI: 10.21037/sci.2019.02.04] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 02/18/2019] [Indexed: 12/11/2022]
Abstract
Stem cells, especially mesenchymal stem cells (MSCs)-based therapies have been greatly attentioned in regenerative medicine through multi-lineage differentiation, self-renewal properties, etc. Despite the above advantages of MSCs, the defined properties of these cells are strongly affected by aging. Thus, the use of MSCs from older donors is lower than younger one, which limits clinical applications in cell therapy. According to the theories of aging, it is determined that aging is most likely caused by telomere shortening and telomere shortening is considered hallmarks of aging. Finding out the most mechanisms of these changes will probably reveal novel therapeutic targets for prolonging human health and for ameliorating age-associated phenotypes. This review focuses on prevalent knowledge about the mechanisms of stem cell senescence by telomere shortening and the molecular mechanism details involved in it.
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Affiliation(s)
- Ezzatollah Fathi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran
| | | | - Zohreh Sanaat
- Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Raheleh Farahzadi
- Hematology and Oncology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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38
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Romanov DE, Butenko EV, Shkurat TP. Genome distance between growth-regulating genes and telomeres is correlated with morpho-physiological traits in mammals. GENE REPORTS 2019. [DOI: 10.1016/j.genrep.2018.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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39
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Mensà E, Latini S, Ramini D, Storci G, Bonafè M, Olivieri F. The telomere world and aging: Analytical challenges and future perspectives. Ageing Res Rev 2019; 50:27-42. [PMID: 30615937 DOI: 10.1016/j.arr.2019.01.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/15/2018] [Accepted: 01/03/2019] [Indexed: 12/12/2022]
Abstract
Telomeres, the terminal nucleoprotein structures of eukaryotic chromosomes, play pleiotropic functions in cellular and organismal aging. Telomere length (TL) varies throughout life due to the influence of genetic factors and to a complex balancing between "shortening" and "elongation" signals. Telomerase, the only enzyme that can elongate a telomeric DNA chain, and telomeric repeat-containing RNA (TERRA), a long non-coding RNA involved in looping maintenance, play key roles in TL during life. Despite recent advances in the knowledge of TL, TERRA and telomerase activity (TA) biology and their measurement techniques, the experimental and theoretical issues involved raise a number of problems that should carefully be considered by researchers approaching the "telomere world". The increasing use of such parameters - hailed as promising clinically relevant biomarkers - has failed to be paralleled by the development of automated and standardized measurement technology. Consequently, associating given TL values to specific pathological conditions involves on the one hand technological issues and on the other clinical-biological issues related to the planning of clinically relevant association studies. Addressing these issues would help avoid major biases in association studies involving TL and a number of outcomes, especially those focusing on psychological and bio-behavioral variables. The main challenge in telomere research is the development of accurate and reliable measurement methods to achieve simple and sensitive TL, TERRA, and TA detection. The discovery of the localization of telomeres and TERRA in cellular and extracellular compartments had added an additional layer of complexity to the measurement of these age-related biomarkers. Since combined analysis of TL, TERRA and TA may well provide more exhaustive clinical information than a single parameter, we feel it is important for researchers in the various fields to become familiar with their most common measurement techniques and to be aware of the respective merits and drawbacks of these approaches.
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Affiliation(s)
- Emanuela Mensà
- Department of Clinical and Molecular Sciences, DISCLIMO, Università Politecnica delle Marche, Ancona, Italy
| | - Silvia Latini
- Department of Clinical and Molecular Sciences, DISCLIMO, Università Politecnica delle Marche, Ancona, Italy
| | - Deborah Ramini
- Department of Clinical and Molecular Sciences, DISCLIMO, Università Politecnica delle Marche, Ancona, Italy
| | - Gianluca Storci
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy; Interdepartmental Centre "L. Galvani" (CIG), University of Bologna, Bologna, Italy
| | - Massimiliano Bonafè
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy; Interdepartmental Centre "L. Galvani" (CIG), University of Bologna, Bologna, Italy; Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST), IRCCS, Biosciences Laboratory, Meldola, Italy
| | - Fabiola Olivieri
- Department of Clinical and Molecular Sciences, DISCLIMO, Università Politecnica delle Marche, Ancona, Italy; Center of Clinical Pathology and Innovative Therapy, IRCCS INRCA, Ancona, Italy.
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40
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Roumelioti FM, Louizou E, Karras S, Neroutsou R, Velissariou V, Gagos S. Unbalanced X;9 translocation in an infertile male with de novo duplication Xp22.31p22.33. J Assist Reprod Genet 2019; 36:769-775. [PMID: 30675680 DOI: 10.1007/s10815-019-01405-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/09/2019] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Male carriers of an X-autosome translocation are generally infertile, regardless of the position of the breakpoint on the X chromosome while the pathogenicity of Xp22.3 subtelomeric duplications is under debate. To shed light into this controversy, we present a rare case, of an azoospermic male with no other significant clinical findings, in whom classical cytogenetics revealed additional unbalanced chromosomal material, at the telomere of the long arm of one homolog of chromosome 9. METHODS In peripheral blood specimens of the index case and his parents, we performed GBanding, Inverted-DAPI Banding, AgNOR staining, Telomere specific Fluorescence in Situ Hybridization (FISH), Molecular karyotyping by Multi-color FISH, whole genome SNP microarrays, sub-telomeric MLPA, and transcription analysis of the expression of KAL1 gene by RT-PCR. RESULTS Multi-color FISH revealed an unbalanced translocation involving the short arm of chromosome X. SNP microarray analysis combined to classical cytogenetics and MLPA demonstrated a de novo 8.796 Mb duplication of Xp22.31-p22.33. Compared to three control specimens, the patient presented significantly elevated expression levels of KAL1 mRNA in peripheral blood, suggesting transcriptional functionality of the duplicated segment. CONCLUSIONS The duplicated segment contains the pseudo-autosomal region PAR1 and more than 30 genes including SHOX, ARSE, STS, KAL1, and FAM9A and is not listed as polymorphic. Our data advocate that duplications of the Xp22.3 region may not be associated with a clinical consequence.
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Affiliation(s)
- Fani-Marlen Roumelioti
- Laboratory of Genetics, Center of Experimental Medicine and Translational Research, Biomedical Research Foundation of the Academy of Athens, (BRFAA), Athens, Greece
| | - Eirini Louizou
- Department of Cytogenetics and Molecular Genetics, Bioiatriki, Group of Health Sciences, Athens, Greece
| | - Spyridon Karras
- Division of Endocrinology and Metabolism, First Department of Internal Medicine, Medical School, Aristotle University of Thessaloniki, AHEPA Hospital, Thessaloniki, Greece
| | - Rozalia Neroutsou
- Department of Cytogenetics and Molecular Genetics, Bioiatriki, Group of Health Sciences, Athens, Greece
| | - Voula Velissariou
- Department of Cytogenetics and Molecular Genetics, Bioiatriki, Group of Health Sciences, Athens, Greece
| | - Sarantis Gagos
- Laboratory of Genetics, Center of Experimental Medicine and Translational Research, Biomedical Research Foundation of the Academy of Athens, (BRFAA), Athens, Greece.
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Laberthonnière C, Magdinier F, Robin JD. Bring It to an End: Does Telomeres Size Matter? Cells 2019; 8:E30. [PMID: 30626097 PMCID: PMC6356554 DOI: 10.3390/cells8010030] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/01/2019] [Accepted: 01/04/2019] [Indexed: 12/22/2022] Open
Abstract
Telomeres are unique nucleoprotein structures. Found at the edge of each chromosome, their main purpose is to mask DNA ends from the DNA-repair machinery by formation of protective loops. Through life and cell divisions, telomeres shorten and bring cells closer to either cell proliferation crisis or senescence. Beyond this mitotic clock role attributed to the need for telomere to be maintained over a critical length, the very tip of our DNA has been shown to impact transcription by position effect. TPE and a long-reach counterpart, TPE-OLD, are mechanisms recently described in human biology. Still in infancy, the mechanism of action of these processes and their respective genome wide impact remain to be resolved. In this review, we will discuss recent findings on telomere dynamics, TPE, TPE-OLD, and lessons learnt from model organisms.
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Affiliation(s)
| | - Frédérique Magdinier
- Aix Marseille Univ, MMG, Marseille Medical Genetics U1251, 13385 Marseille, France.
| | - Jérôme D Robin
- Aix Marseille Univ, MMG, Marseille Medical Genetics U1251, 13385 Marseille, France.
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