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Wang QL, Gong C, Meng XY, Fu M, Yang H, Zhou F, Wu Q, Zhou Y. TPP1 is associated with risk of advanced precursors and cervical cancer survival. PLoS One 2024; 19:e0298118. [PMID: 38722833 PMCID: PMC11081309 DOI: 10.1371/journal.pone.0298118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/16/2024] [Indexed: 05/13/2024] Open
Abstract
It is unclear how telomere-binding protein TPP1 interacts with human telomerase reverse transcriptase (hTERT) and influences cervical cancer development and progression. This study included all eligible 156 cervical cancers diagnosed during 2003-2008 and followed up through 2014, 102 cervical intraepithelial neoplasia (CIN) patients, and 16 participants with normal cervix identified at the same period. Correlation of expression of TPP1 and hTERT in these lesions was assessed using Kappa statistics. TPP1 was knocked down by siRNA in three cervical cancer cell lines. We assessed mRNA expression using quantitative real-time polymerase chain reaction and protein expression using tissue microarray-based immunohistochemical staining. We further analyzed the impact of TPP1 expression on the overall survival of cervical cancer patients by calculating the hazard ratio (HR) with 95% confidence intervals (CIs) using the multivariable-adjusted Cox regression model. Compared to the normal cervix, high TPP1expression was significantly associated with CIN 3 and cervical cancers (P<0.001 for both). Expressions of TPP1 and hTERT were highly correlated in CIN 3 (Kappa statistics = 0.50, P = 0.005), squamous cell carcinoma (Kappa statistics = 0.22, P = 0.011), and adenocarcinoma/adenosquamous carcinoma (Kappa statistics = 0.77, P = 0.001). Mechanistically, knockdown of TPP1 inhibited the expression of hTERT in both mRNA and protein levels. High expression of TPP1 (HR = 2.61, 95% CI 1.23-5.51) and co-high expression of TPP1 and hTERT (HR = 2.38, 95% CI 1.28-4.43) were independently associated with worse survival in cervical cancer patients. TPP1 and hTERT expression was correlated and high expression of TPP1 was associated with high risk of CIN 3 and cervical cancer and could predict a worse survival in cervical cancer.
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Affiliation(s)
- Qiao-Li Wang
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, United States of America
| | - Caifeng Gong
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
- Department of Medical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiang-Yu Meng
- Health Science Center, Hubei Minzu University, Enshi, China
| | - Min Fu
- Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Yang
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
| | - Fuxiang Zhou
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
| | - Qiuji Wu
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
| | - Yunfeng Zhou
- Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital of Wuhan University, Hubei Cancer Clinical Study Center, Wuhan, Hubei, China
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Bertrand A, Ba I, Kermasson L, Pirabakaran V, Chable N, Lainey E, Ménard C, Kallel F, Picard C, Hadiji S, Coolen-Allou N, Blanchard E, de Villartay JP, Moshous D, Roelens M, Callebaut I, Kannengiesser C, Revy P. Characterization of novel mutations in the TEL-patch domain of the telomeric factor TPP1 associated with telomere biology disorders. Hum Mol Genet 2024; 33:612-623. [PMID: 38176734 DOI: 10.1093/hmg/ddad210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 12/04/2023] [Accepted: 12/13/2023] [Indexed: 01/06/2024] Open
Abstract
Telomeres are nucleoprotein structures that protect the chromosome ends from degradation and fusion. Telomerase is a ribonucleoprotein complex essential to maintain the length of telomeres. Germline defects that lead to short and/or dysfunctional telomeres cause telomere biology disorders (TBDs), a group of rare and heterogeneous Mendelian diseases including pulmonary fibrosis, dyskeratosis congenita, and Høyeraal-Hreidarsson syndrome. TPP1, a telomeric factor encoded by the gene ACD, recruits telomerase at telomere and stimulates its activity via its TEL-patch domain that directly interacts with TERT, the catalytic subunit of telomerase. TBDs due to TPP1 deficiency have been reported only in 11 individuals. We here report four unrelated individuals with a wide spectrum of TBD manifestations carrying either heterozygous or homozygous ACD variants consisting in the recurrent and previously described in-frame deletion of K170 (K170∆) and three novel missense mutations G179D, L184R, and E215V. Structural and functional analyses demonstrated that the four variants affect the TEL-patch domain of TPP1 and impair telomerase activity. In addition, we identified in the ACD gene several motifs associated with small deletion hotspots that could explain the recurrence of the K170∆ mutation. Finally, we detected in a subset of blood cells from one patient, a somatic TERT promoter-activating mutation that likely provides a selective advantage over non-modified cells, a phenomenon known as indirect somatic genetic rescue. Together, our results broaden the genetic and clinical spectrum of TPP1 deficiency and specify new residues in the TEL-patch domain that are crucial for length maintenance and stability of human telomeres in vivo.
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Affiliation(s)
- Alexis Bertrand
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Ibrahima Ba
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Service de Génétique, Université Paris Diderot, Paris 75018, France
| | - Laëtitia Kermasson
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Vithura Pirabakaran
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Noémie Chable
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Elodie Lainey
- Hematology Laboratory, Robert Debré Hospital-AssistancePublique-Hôpitaux de Paris (APHP), INSERM UMR 1131-Hematology University Institute-Denis Diderot School of Medicine, Paris 75019, France
| | - Christelle Ménard
- Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Service de Génétique, Université Paris Diderot, Paris 75018, France
| | - Faten Kallel
- Hematology Department, Hedi Chaker Hospital, 3029, Sfax, Tunisia
| | - Capucine Picard
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Department of Pediatric Immunology, Hematology and Rheumatology, Necker-Enfants Malades Hospital, (APHP), Paris 75015, France
- Centre de références des déficits immunitaires Héréditaires (CEREDIH), Necker-Enfants Malades Hospital APHP, Paris 75015, France
- Laboratory of Lymphocyte Activation and Susceptibility to EBV infection, Inserm UMR 1163, Institut Imagine, Paris 75015, France
| | - Sondes Hadiji
- Hematology Department, Hedi Chaker Hospital, 3029, Sfax, Tunisia
| | - Nathalie Coolen-Allou
- Service de Pneumologie, Hôpital Félix Guyon, CHU Réunion, Saint-Denis de la Réunion 97400, France
| | - Elodie Blanchard
- Service de Pneumologie, Hôpital Haut-Lévêque, CHU Bordeaux, Bordeaux 33604, France
| | - Jean-Pierre de Villartay
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Despina Moshous
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Department of Pediatric Immunology, Hematology and Rheumatology, Necker-Enfants Malades Hospital, (APHP), Paris 75015, France
| | - Marie Roelens
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Centre de références des déficits immunitaires Héréditaires (CEREDIH), Necker-Enfants Malades Hospital APHP, Paris 75015, France
| | - Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Paris 75005, France
| | - Caroline Kannengiesser
- Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Service de Génétique, Université Paris Diderot, Paris 75018, France
| | - Patrick Revy
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
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3
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Adav SS, Ng KW. Recent omics advances in hair aging biology and hair biomarkers analysis. Ageing Res Rev 2023; 91:102041. [PMID: 37634889 DOI: 10.1016/j.arr.2023.102041] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/27/2023] [Accepted: 08/23/2023] [Indexed: 08/29/2023]
Abstract
Aging is a complex natural process that leads to a decline in physiological functions, which is visible in signs such as hair graying, thinning, and loss. Although hair graying is characterized by a loss of pigment in the hair shaft, the underlying mechanism of age-associated hair graying is not fully understood. Hair graying and loss can have a significant impact on an individual's self-esteem and self-confidence, potentially leading to mental health problems such as depression and anxiety. Omics technologies, which have applications beyond clinical medicine, have led to the discovery of candidate hair biomarkers and may provide insight into the complex biology of hair aging and identify targets for effective therapies. This review provides an up-to-date overview of recent omics discoveries, including age-associated alterations of proteins and metabolites in the hair shaft and follicle, and highlights the significance of hair aging and graying biomarker discoveries. The decline in hair follicle stem cell activity with aging decreased the regeneration capacity of hair follicles. Cellular senescence, oxidative damage and altered extracellular matrix of hair follicle constituents characterized hair follicle and hair shaft aging and graying. The review attempts to correlate the impact of endogenous and exogenous factors on hair aging. We close by discussing the main challenges and limitations of the field, defining major open questions and offering an outlook for future research.
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Affiliation(s)
- Sunil S Adav
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Kee Woei Ng
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore; Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141, Singapore.
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4
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Ding D, Gao R, Xue Q, Luan R, Yang J. Genomic Fingerprint Associated with Familial Idiopathic Pulmonary Fibrosis: A Review. Int J Med Sci 2023; 20:329-345. [PMID: 36860670 PMCID: PMC9969503 DOI: 10.7150/ijms.80358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/12/2023] [Indexed: 02/04/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a severe interstitial lung disease; although the recent introduction of two anti-fibrosis drugs, pirfenidone and Nidanib, have resulted in a significant reduction in lung function decline, IPF is still not curable. Approximately 2-20% of patients with IPF have a family history of the disease, which is considered the strongest risk factor for idiopathic interstitial pneumonia. However, the genetic predispositions of familial IPF (f-IPF), a particular type of IPF, remain largely unknown. Genetics affect the susceptibility and progression of f-IPF. Genomic markers are increasingly being recognized for their contribution to disease prognosis and drug therapy outcomes. Existing data suggest that genomics may help identify individuals at risk for f-IPF, accurately classify patients, elucidate key pathways involved in disease pathogenesis, and ultimately develop more effective targeted therapies. Since several genetic variants associated with the disease have been found in f-IPF, this review systematically summarizes the latest progress in the gene spectrum of the f-IPF population and the underlying mechanisms of f-IPF. The genetic susceptibility variation related to the disease phenotype is also illustrated. This review aims to improve the understanding of the IPF pathogenesis and facilitate his early detection.
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Affiliation(s)
- Dongyan Ding
- Department of Respiratory Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Rong Gao
- Department of Respiratory Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Qianfei Xue
- Hospital of Jilin University, Changchun, China
| | - Rumei Luan
- Department of Respiratory Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Junling Yang
- Department of Respiratory Medicine, The Second Hospital of Jilin University, Changchun, China
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Wen J, Zhong X, Gao C, Yang M, Tang M, Yuan Z, Wang Q, Xu L, Ma Q, Guo X, Fang L. TPP1 Inhibits DNA Damage Response and Chemosensitivity in Esophageal Cancer. Crit Rev Eukaryot Gene Expr 2023; 33:77-91. [PMID: 37606165 DOI: 10.1615/critreveukaryotgeneexpr.2023048720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
TPP1, as one of the telomere-protective protein complex, functions to maintain telomere stability. In this study, we found that TPP1 was significantly upregulated in esophageal cancer (EC). We found that the proliferation and migration ability were significantly inhibited, while the results of flow cytometry assay indicated that the growth was hindered in the G1 phase after TPP1 knockdown. However, the proliferative viability and migratory ability were reversed after TPP1 overexpression in EC cells. Then, we found a significant increase in β-galactosidase positivity following TPP1 knockdown and the opposite following TPP1 overexpression in EC cells. Furthermore, TPP1 knockdown increased DNA damage and upregulated expression of the γ-H2AXS139 in the cell nucleus. Correspondingly, DNA damage was reversed after TPP1 overexpression in EC cells. Similarly, we found that the expression of ATM/ATR pathway proteins were upregulated after TPP1 knockdown, while the expression of the above proteins was downregulated after TPP1 overexpression in EC cells. TPP1 knockdown significantly inhibited the growth of transplanted tumors and upregulated the expression of ATM/ATR pathway proteins in transplanted tissues, whereas TPP1 overexpression significantly promoted their proliferation and downregulated the expression of the above proteins in vivo. Strikingly, we found that TPP1 could reduce the chemosensitivity of EC cells to cisplatin, which may have a potential link to clinical chemoresistance. In conclusion, TPP1 regulates the DNA damage response through the ATM/ATR-p53 signaling pathway and chemoresistance and may be a new target for improving the efficacy of chemotherapy in the treatment of EC.
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Affiliation(s)
- Jilin Wen
- Department of Laboratory Medicine, North Sichuan Medical College, Nanchong 637000, China
| | - Xiaowu Zhong
- Department of Laboratory Medicine, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China; Department of Laboratory Medicine, North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China
| | - Chuanli Gao
- Department of Laboratory Medicine, North Sichuan Medical College, Nanchong 637000, China
| | - Miyuan Yang
- Department of Laboratory Medicine, North Sichuan Medical College, Nanchong 637000, China
| | - Maoju Tang
- Department of Laboratory Medicine, North Sichuan Medical College, Nanchong 637000, China
| | - Zichun Yuan
- Department of Laboratory Medicine, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China; Department of Laboratory Medicine, North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China
| | - Qin Wang
- Department of Laboratory Medicine, North Sichuan Medical College, Nanchong 637000, China
| | - Lei Xu
- Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China
| | - Qiang Ma
- Department of Laboratory Medicine, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China; Department of Laboratory Medicine, North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China
| | - Xiaolan Guo
- Department of Laboratory Medicine, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China; Department of Laboratory Medicine, North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China; Translational Medicine Research Center, North Sichuan Medical College, Nanchong, Sichuan 637000, P.R. China
| | - Li Fang
- Department of Laboratory Medicine, North Sichuan Medical College, Nanchong 637000, China; Department of Clinical Laboratory, Affiliated Hospital of North Sichuan Medical College, Nanchong 637000, China
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6
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Knockout of Shelterin subunit genes in zebrafish results in distinct outcomes. Biochem Biophys Res Commun 2022; 617:22-29. [DOI: 10.1016/j.bbrc.2022.05.079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 05/24/2022] [Indexed: 11/23/2022]
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Mitoribosomal Deregulation Drives Senescence via TPP1-Mediated Telomere Deprotection. Cells 2022; 11:cells11132079. [PMID: 35805162 PMCID: PMC9265344 DOI: 10.3390/cells11132079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/13/2022] [Accepted: 06/28/2022] [Indexed: 11/17/2022] Open
Abstract
While mitochondrial bioenergetic deregulation has long been implicated in cellular senescence, its mechanistic involvement remains unclear. By leveraging diverse mitochondria-related gene expression profiles derived from two different cellular senescence models of human diploid fibroblasts, we found that the expression of mitoribosomal proteins (MRPs) was generally decreased during the early-to-middle transition prior to the exhibition of noticeable SA-β-gal activity. Suppressed expression patterns of the identified senescence-associated MRP signatures (SA-MRPs) were validated in aged human cells and rat and mouse skin tissues and in aging mouse fibroblasts at single-cell resolution. TIN2- and POT1-interaction protein (TPP1) was concurrently suppressed, which induced senescence, accompanied by telomere DNA damage. Lastly, we show that SA-MRP deregulation could be a potential upstream regulator of TPP1 suppression. Our results indicate that mitoribosomal deregulation could represent an early event initiating mitochondrial dysfunction and serve as a primary driver of cellular senescence and an upstream regulator of shelterin-mediated telomere deprotection.
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Martínez P, Sánchez-Vázquez R, Ferrara-Romeo I, Serrano R, Flores JM, Blasco MA. A mouse model for Li-Fraumeni-Like Syndrome with cardiac angiosarcomas associated to POT1 mutations. PLoS Genet 2022; 18:e1010260. [PMID: 35727838 PMCID: PMC9212151 DOI: 10.1371/journal.pgen.1010260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 05/16/2022] [Indexed: 11/18/2022] Open
Abstract
The shelterin protein POT1 has been found mutated in many different familial and sporadic cancers, however, no mouse models to understand the pathobiology of these mutations have been developed so far. To address the molecular mechanisms underlying the tumorigenic effects of POT1 mutant proteins in humans, we have generated a mouse model for the human POT1R117C mutation found in Li-Fraumeni-Like families with cases of cardiac angiosarcoma by introducing this mutation in the Pot1a endogenous locus, knock-in for Pot1aR117C. We find here that both mouse embryonic fibroblasts (MEFs) and tissues from Pot1a+/ki mice show longer telomeres than wild-type controls. Longer telomeres in Pot1a+/ki MEFs are dependent on telomerase activity as they are not found in double mutant Pot1a+/kiTert-/- telomerase-deficient MEFs. By using complementation assays we further show that POT1a pR117C exerts dominant-negative effects at telomeres. As in human Li-Fraumeni patients, heterozygous Pot1a+/ki mice spontaneously develop a high incidence of angiosarcomas, including cardiac angiosarcomas, and this is associated to the presence of abnormally long telomeres in endothelial cells as well as in the tumors. The Pot1a+/R117C mouse model constitutes a useful tool to understand human cancers initiated by POT1 mutations. We have generated a mouse model for the human POT1R117C mutation found in Li-Fraumeni-Like (LFL) families with cases of cardiac angiosarcoma by introducing this mutation in the Pot1a endogenous locus, knock-in for Pot1aR117C. The Pot1a+/ki mice show longer telomeres than wild-type controls. Longer telomeres in mutant mice are dependent on telomerase activity as they are not found in a telomerase deficient background. As in human Li-Fraumeni patients, heterozygous Pot1a+/ki mice spontaneously develop a high incidence of angiosarcomas, including cardiac angiosarcomas, and this is associated to the presence of abnormally long telomeres in endothelial cells as well as in the tumors. The ki-Pot1aR117C mouse constitutes a potential pre-clinical mouse model for LFL syndrome presenting with high angiosarcoma incidence that could provide in the future a very useful tool for the study of treatments for these tumors.
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Affiliation(s)
- Paula Martínez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
| | - Raúl Sánchez-Vázquez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
| | - Iole Ferrara-Romeo
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
| | - Rosa Serrano
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
| | - Juana M. Flores
- Animal Surgery and Medicine Department, Faculty of Veterinary Science, Complutense University of Madrid, Madrid, Spain
| | - Maria A. Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
- * E-mail:
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Aramburu T, Kelich J, Rice C, Skordalakes E. POT1-TPP1 binding stabilizes POT1, promoting efficient telomere maintenance. Comput Struct Biotechnol J 2022; 20:675-684. [PMID: 35140887 PMCID: PMC8803944 DOI: 10.1016/j.csbj.2022.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/07/2022] [Accepted: 01/07/2022] [Indexed: 11/20/2022] Open
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Telomeres and Cancer. Life (Basel) 2021; 11:life11121405. [PMID: 34947936 PMCID: PMC8704776 DOI: 10.3390/life11121405] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/01/2021] [Accepted: 12/06/2021] [Indexed: 12/18/2022] Open
Abstract
Telomeres cap the ends of eukaryotic chromosomes and are indispensable chromatin structures for genome protection and replication. Telomere length maintenance has been attributed to several functional modulators, including telomerase, the shelterin complex, and the CST complex, synergizing with DNA replication, repair, and the RNA metabolism pathway components. As dysfunctional telomere maintenance and telomerase activation are associated with several human diseases, including cancer, the molecular mechanisms behind telomere length regulation and protection need particular emphasis. Cancer cells exhibit telomerase activation, enabling replicative immortality. Telomerase reverse transcriptase (TERT) activation is involved in cancer development through diverse activities other than mediating telomere elongation. This review describes the telomere functions, the role of functional modulators, the implications in cancer development, and the future therapeutic opportunities.
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11
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Tsai YY, Su CH, Tarn WY. p53 Activation in Genetic Disorders: Different Routes to the Same Destination. Int J Mol Sci 2021; 22:9307. [PMID: 34502215 PMCID: PMC8430931 DOI: 10.3390/ijms22179307] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 12/18/2022] Open
Abstract
The tumor suppressor p53 is critical for preventing neoplastic transformation and tumor progression. Inappropriate activation of p53, however, has been observed in a number of human inherited disorders that most often affect development of the brain, craniofacial region, limb skeleton, and hematopoietic system. Genes related to these developmental disorders are essentially involved in transcriptional regulation/chromatin remodeling, rRNA metabolism, DNA damage-repair pathways, telomere maintenance, and centrosome biogenesis. Perturbation of these activities or cellular processes may result in p53 accumulation in cell cultures, animal models, and perhaps humans as well. Mouse models of several p53 activation-associated disorders essentially recapitulate human traits, and inactivation of p53 in these models can alleviate disorder-related phenotypes. In the present review, we focus on how dysfunction of the aforementioned biological processes causes developmental defects via excessive p53 activation. Notably, several disease-related genes exert a pleiotropic effect on those cellular processes, which may modulate the magnitude of p53 activation and establish or disrupt regulatory loops. Finally, we discuss potential therapeutic strategies for genetic disorders associated with p53 misactivation.
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Tang LJ, Rios RS, Zhang H, Byrne CD, Targher G, Zheng MH. Telomerase: a key player in the pathogenesis of non-alcoholic fatty liver disease? Expert Rev Gastroenterol Hepatol 2021; 15:811-819. [PMID: 33709875 DOI: 10.1080/17474124.2021.1903318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Telomerase is a basic nuclear protein reverse transcriptase, which plays a key role in maintaining telomere stability, genome integrity, long-term cell activity, and potential continued proliferation.Area covered: This narrative review discusses key research advances involving telomerase in the development and progression of nonalcoholic fatty liver disease (NAFLD). The review evaluates 9a) whether the assessment of telomerase can be used as a noninvasive diagnostic tool; and (b) whether modification of telomerase function might be a useful potential therapeutic target for treatment of NAFLD. Furthermore, the relationship between telomerase and other chronic metabolic diseases is evaluated.Expert opinion: Several experimental and preclinical studies have suggested that telomerase plays an important role in the development of NAFLD. However, further mechanistic studies are needed to prove a causal relationship and to better elucidate whether the measurement of telomerase has utility as a diagnostic tool or whether pharmacological manipulation of telomerase has therapeutic potential in NAFLD treatment.
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Affiliation(s)
- Liang-Jie Tang
- NAFLD Research Center, Department of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Rafael S Rios
- NAFLD Research Center, Department of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Huai Zhang
- NAFLD Research Center, Department of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Christopher D Byrne
- Southampton National Institute for Health Research Biomedical Research Centre, University Hospital Southampton, Southampton General Hospital, Southampton, UK
| | - Giovanni Targher
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Azienda Ospedaliera Universitaria Integrata of Verona, Verona, Italy
| | - Ming-Hua Zheng
- NAFLD Research Center, Department of Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.,Institute of Hepatology, Wenzhou Medical University, Wenzhou, China.,Key Laboratory of Diagnosis and Treatment for the Development of Chronic Liver Disease in Zhejiang Province, Wenzhou, China
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13
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Stone RC, Aviv A, Paus R. Telomere Dynamics and Telomerase in the Biology of Hair Follicles and their Stem Cells as a Model for Aging Research. J Invest Dermatol 2021; 141:1031-1040. [PMID: 33509633 DOI: 10.1016/j.jid.2020.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/28/2020] [Accepted: 12/01/2020] [Indexed: 02/06/2023]
Abstract
In this review, we propose that telomere length dynamics play an important but underinvestigated role in the biology of the hair follicle (HF), a prototypic, cyclically remodeled miniorgan that shows an intriguing aging pattern in humans. Whereas the HF pigmentary unit ages quickly, its epithelial stem cell (ESC) component and regenerative capacity are surprisingly aging resistant. Telomerase-deficient mice with short telomeres display an aging phenotype of hair graying and hair loss that is attributed to impaired HF ESC mobilization. Yet, it remains unclear whether the function of telomerase and telomeres in murine HF biology translate to the human system. Therefore, we propose new directions for future telomere research of the human HF. Such research may guide the development of novel treatments for selected disorders of human hair growth or pigmentation (e.g., chemotherapy-induced alopecia, telogen effluvium, androgenetic alopecia, cicatricial alopecia, graying). It might also increase the understanding of the global role of telomeres in aging-related human disease.
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Affiliation(s)
- Rivka C Stone
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA.
| | - Abraham Aviv
- The Center of Human Development and Aging, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Ralf Paus
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA; Centre for Dermatology Research, University of Manchester, Manchester, United Kingdom; Monasterium Laboratory, Münster, Germany
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14
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AKT-dependent signaling of extracellular cues through telomeres impact on tumorigenesis. PLoS Genet 2021; 17:e1009410. [PMID: 33690611 PMCID: PMC7942993 DOI: 10.1371/journal.pgen.1009410] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/09/2021] [Indexed: 12/27/2022] Open
Abstract
The telomere-bound shelterin complex is essential for chromosome-end protection and genomic stability. Little is known on the regulation of shelterin components by extracellular signals including developmental and environmental cues. Here, we show that human TRF1 is subjected to AKT-dependent regulation. To study the importance of this modification in vivo, we generate knock-in human cell lines carrying non-phosphorylatable mutants of the AKT-dependent TRF1 phosphorylation sites by CRISPR-Cas9. We find that TRF1 mutant cells show decreased TRF1 binding to telomeres and increased global and telomeric DNA damage. Human cells carrying non-phosphorylatable mutant TRF1 alleles show accelerated telomere shortening, demonstrating that AKT-dependent TRF1 phosphorylation regulates telomere maintenance in vivo. TRF1 mutant cells show an impaired response to proliferative extracellular signals as well as a decreased tumorigenesis potential. These findings indicate that telomere protection and telomere length can be regulated by extracellular signals upstream of PI3K/AKT activation, such as growth factors, nutrients or immune regulators, and this has an impact on tumorigenesis potential. We show how extracellular milieu information is transmitted to the nucleus through modifications in the telomeric protein TRF1. TRF1, a component of the shelterin complex that protects the ends of our chromosomes, is modified by the PI3K/AKT signaling pathway, which senses the extracellular nutritional conditions. We generated knock-in human cell lines carrying mutant TRF1 variants unable to be modified by AKT. TRF1 mutant cells show decreased TRF1 binding to telomeres, increased DNA damage and accelerated telomere shortening. TRF1 mutant cells show an impaired TRF1 stability in response to proliferative extracellular signals and a decreased tumorigenesis potential, demonstrating that telomere function and telomere length are regulated by extracellular signals upstream of PI3K/AKT activation.
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15
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Boyle JM, Hennick KM, Regalado SG, Vogan JM, Zhang X, Collins K, Hockemeyer D. Telomere length set point regulation in human pluripotent stem cells critically depends on the shelterin protein TPP1. Mol Biol Cell 2020; 31:2583-2596. [PMID: 32903138 PMCID: PMC7851873 DOI: 10.1091/mbc.e19-08-0447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Telomere maintenance is essential for the long-term proliferation of human pluripotent stem cells, while their telomere length set point determines the proliferative capacity of their differentiated progeny. The shelterin protein TPP1 is required for telomere stability and elongation, but its role in establishing a telomere length set point remains elusive. Here, we characterize the contribution of the shorter isoform of TPP1 (TPP1S) and the amino acid L104 outside the TEL patch, TPP1’s telomerase interaction domain, to telomere length control. We demonstrate that cells deficient for TPP1S (TPP1S knockout [KO]), as well as the complete TPP1 KO cell lines, undergo telomere shortening. However, TPP1S KO cells are able to stabilize short telomeres, while TPP1 KO cells die. We compare these phenotypes with those of TPP1L104A/L104A mutant cells, which have short and stable telomeres similar to the TPP1S KO. In contrast to TPP1S KO cells, TPP1L104A/L104A cells respond to increased telomerase levels and maintain protected telomeres. However, TPP1L104A/L104A shows altered sensitivity to expression changes of shelterin proteins suggesting the mutation causes a defect in telomere length feedback regulation. Together this highlights TPP1L104A/L104A as the first shelterin mutant engineered at the endogenous locus of human stem cells with an altered telomere length set point.
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Affiliation(s)
- John M Boyle
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Kelsey M Hennick
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Samuel G Regalado
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Jacob M Vogan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Xiaozhu Zhang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Kathleen Collins
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720.,Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720.,Chan Zuckerberg Biohub, San Francisco, CA 94158
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16
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Razgonova MP, Zakharenko AM, Golokhvast KS, Thanasoula M, Sarandi E, Nikolouzakis K, Fragkiadaki P, Tsoukalas D, Spandidos DA, Tsatsakis A. Telomerase and telomeres in aging theory and chronographic aging theory (Review). Mol Med Rep 2020; 22:1679-1694. [PMID: 32705188 PMCID: PMC7411297 DOI: 10.3892/mmr.2020.11274] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/24/2020] [Indexed: 01/03/2023] Open
Abstract
The current review focuses on the connection of telomerase and telomeres with aging. In this review, we describe the changes in telomerase and telomere length (TEL) during development, their role in carcinogenesis processes, and the consequences of reduced telomerase activity. More specifically, the connection of TEL in peripheral blood cells with the development of aging‑associated diseases is discussed. The review provides systematic data on the role of telomerase in mitochondria, the biology of telomeres in stem cells, as well as the consequences of the forced expression of telomerase (telomerization) in human cells. Additionally, it presents the effects of chronic stress exposure on telomerase activity, the effect of TEL on fertility, and the effect of nutraceutical supplements on TEL. Finally, a comparative review of the chronographic theory of aging, presented by Olovnikov is provided based on currently available scientific research on telomere, telomerase activity, and the nature of aging by multicellular organisms.
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Affiliation(s)
- Mayya P. Razgonova
- N.I. Vavilov All-Russian Institute of Plant Genetic Resources, 190000 Saint-Petersburg, Russia
- Far Eastern Federal University, 690950 Vladivostok, Russia
| | - Alexander M. Zakharenko
- N.I. Vavilov All-Russian Institute of Plant Genetic Resources, 190000 Saint-Petersburg, Russia
- Far Eastern Federal University, 690950 Vladivostok, Russia
| | - Kirill S. Golokhvast
- N.I. Vavilov All-Russian Institute of Plant Genetic Resources, 190000 Saint-Petersburg, Russia
- Far Eastern Federal University, 690950 Vladivostok, Russia
- Pacific Geographical Institute, Far Eastern Branch of The Russian Academy of Sciences, 690041 Vladivostok, Russia
| | - Maria Thanasoula
- Metabolomic Μedicine, Health Clinics for Autoimmune and Chronic Diseases, 10674 Athens, Greece
| | - Evangelia Sarandi
- Metabolomic Μedicine, Health Clinics for Autoimmune and Chronic Diseases, 10674 Athens, Greece
| | | | - Persefoni Fragkiadaki
- Laboratory of Toxicology, Medical School, University of Crete, 71003 Heraklion, Greece
- Spin-Off Toxplus S.A., 71601 Heraklion, Greece
| | - Dimitris Tsoukalas
- Metabolomic Μedicine, Health Clinics for Autoimmune and Chronic Diseases, 10674 Athens, Greece
| | - Demetrios A. Spandidos
- Laboratory of Clinical Virology, School of Medicine, University of Crete, Heraklion 71003, Greece
| | - Aristidis Tsatsakis
- Laboratory of Toxicology, Medical School, University of Crete, 71003 Heraklion, Greece
- Spin-Off Toxplus S.A., 71601 Heraklion, Greece
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17
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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 PMCID: PMC7383370 DOI: 10.1074/jbc.rev119.009710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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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18
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Mir SM, Samavarchi Tehrani S, Goodarzi G, Jamalpoor Z, Asadi J, Khelghati N, Qujeq D, Maniati M. Shelterin Complex at Telomeres: Implications in Ageing. Clin Interv Aging 2020; 15:827-839. [PMID: 32581523 PMCID: PMC7276337 DOI: 10.2147/cia.s256425] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 05/18/2020] [Indexed: 12/16/2022] Open
Abstract
Different factors influence the development and control of ageing. It is well known that progressive telomere shorting is one of the molecular mechanisms underlying ageing. The shelterin complex consists of six telomere-specific proteins which are involved in the protection of chromosome ends. More particularly, this vital complex protects the telomeres from degradation, prevents from activation of unwanted repair systems, regulates the activity of telomerase, and has a crucial role in cellular senescent and ageing-related pathologies. This review explores the organization and function of telomeric DNA along with the mechanism of telomeres during ageing, followed by a discussion of the critical role of shelterin components and their changes during ageing.
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Affiliation(s)
- Seyed Mostafa Mir
- Trauma Research Center, AJA University of Medical Sciences, Tehran, Iran.,Student Research Committee, Babol University of Medical Sciences, Babol, Iran.,Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Sadra Samavarchi Tehrani
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Student Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Golnaz Goodarzi
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Student Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Jamalpoor
- Trauma Research Center, AJA University of Medical Sciences, Tehran, Iran
| | - Jahanbakhsh Asadi
- Metabolic Disorders Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Nafiseh Khelghati
- Department of Clinical Biochemistry, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Durdi Qujeq
- Student Research Committee, Babol University of Medical Sciences, Babol, Iran.,Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Mahmood Maniati
- School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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19
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Abstract
Telomeres, the protective ends of linear chromosomes, shorten throughout an individual's lifetime. Accumulation of critically short telomeres is proposed to be a primary molecular cause of aging and age-associated diseases. Mutations in telomere maintenance genes are associated with pathologies referred to as or telomeropathies. The rate of telomere shortening throughout life is determined by endogenous (genetic) and external (nongenetic) factors. Therapeutic strategies based on telomerase activation are being developed to treat and prevent telomere-associated diseases, namely aging-related diseases and telomeropathies. Here, we review the molecular mechanisms underlying telomere driven diseases with particular emphasis on cardiovascular diseases.
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Affiliation(s)
- Paula Martínez
- From the Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
| | - Maria A Blasco
- From the Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
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20
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Liu N, Yin Y, Wang H, Zhou Z, Sheng X, Fu H, Guo R, Wang H, Yang J, Gong P, Ning W, Ju Z, Liu Y, Liu L. Telomere dysfunction impairs epidermal stem cell specification and differentiation by disrupting BMP/pSmad/P63 signaling. PLoS Genet 2019; 15:e1008368. [PMID: 31518356 PMCID: PMC6760834 DOI: 10.1371/journal.pgen.1008368] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 09/25/2019] [Accepted: 08/12/2019] [Indexed: 11/19/2022] Open
Abstract
Telomere shortening is associated with aging and age-associated diseases. Additionally, telomere dysfunction resulting from telomerase gene mutation can lead to premature aging, such as apparent skin atrophy and hair loss. However, the molecular signaling linking telomere dysfunction to skin atrophy remains elusive. Here we show that dysfunctional telomere disrupts BMP/pSmad/P63 signaling, impairing epidermal stem cell specification and differentiation of skin and hair follicles. We find that telomere shortening mediated by Terc loss up-regulates Follistatin (Fst), inhibiting pSmad signaling and down-regulating P63 and epidermal keratins in an ESC differentiation model as well as in adult development of telomere-shortened mice. Mechanistically, short telomeres disrupt PRC2/H3K27me3-mediated repression of Fst. Our findings reveal that skin atrophy due to telomere dysfunction is caused by a previously unappreciated link with Fst and BMP signaling that could be explored in the development of therapies.
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Affiliation(s)
- Na Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
- Key Laboratory of Bioactive Materials, Ministry of Education, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin, China
- School of Medicine, Nankai University, Tianjin, China
| | - Yu Yin
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
- Yunnan Key Laboratory of Primate Biomedical Research; Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
| | - Haiying Wang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Zhongcheng Zhou
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Xiaoyan Sheng
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Haifeng Fu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Renpeng Guo
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Hua Wang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Jiao Yang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Peng Gong
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Wen Ning
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Zhenyu Ju
- Key Laboratory of Regenerative Medicine of Ministry of Education, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou, China
| | - Yifei Liu
- Yale Fertility Center and Department of OB/GYN, Yale University School of Medicine, New Haven, CT, United States of America
- * E-mail: (YL); (LL)
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
- Key Laboratory of Bioactive Materials, Ministry of Education, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin, China
- * E-mail: (YL); (LL)
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21
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Chen X, Tang WJ, Shi JB, Liu MM, Liu XH. Therapeutic strategies for targeting telomerase in cancer. Med Res Rev 2019; 40:532-585. [PMID: 31361345 DOI: 10.1002/med.21626] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/12/2019] [Accepted: 07/16/2019] [Indexed: 12/13/2022]
Abstract
Telomere and telomerase play important roles in abnormal cell proliferation, metastasis, stem cell maintenance, and immortalization in various cancers. Therefore, designing of drugs targeting telomerase and telomere is of great significance. Over the past two decades, considerable knowledge regarding telomere and telomerase has been accumulated, which provides theoretical support for the design of therapeutic strategies such as telomere elongation. Therefore, the development of telomere-based therapies such as nucleoside analogs, non-nucleoside small molecules, antisense technology, ribozymes, and dominant negative human telomerase reverse transcriptase are being prioritized for eradicating a majority of tumors. While the benefits of telomere-based therapies are obvious, there is a need to address the limitations of various therapeutic strategies to improve the possibility of clinical applications. In this study, current knowledge of telomere and telomerase is discussed, and therapeutic strategies based on recent research are reviewed.
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Affiliation(s)
- Xing Chen
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Wen-Jian Tang
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Jing Bo Shi
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Ming Ming Liu
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
| | - Xin-Hua Liu
- School of Pharmacy, Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, People's Republic of China
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22
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The role of telomere-binding modulators in pluripotent stem cells. Protein Cell 2019; 11:60-70. [PMID: 31350723 PMCID: PMC6949317 DOI: 10.1007/s13238-019-0651-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/07/2019] [Indexed: 01/24/2023] Open
Abstract
Pluripotent stem cells (PSCs) such as embryonic stem cells (ESCs), ESCs derived by somatic cell nuclear transfer (ntESCs), and induced pluripotent stem cells (iPSCs) have unlimited capacity for self-renewal and pluripotency and can give rise to all types of somatic cells. In order to maintain their self-renewal and pluripotency, PSCs need to preserve their telomere length and homeostasis. In recent years, increasing studies have shown that telomere reprogramming is essential for stem cell pluripotency maintenance and its induced pluripotency process. Telomere-associated proteins are not only required for telomere maintenance in both stem cells, their extra-telomeric functions have also been found to be critical as well. Here, we will discuss how telomeres and telomere-associated factors participate and regulate the maintenance of stem cell pluripotency.
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23
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Polito F, Cucinotta M, Abbritti RV, Brogna A, Pergolizzi S, Tomasello C, Barresi V, Angileri FF, Di Giorgio R, Conti A, La Torre D, Germanò A, Aguennouz M. Silencing of telomere-binding protein adrenocortical dysplasia (ACD) homolog enhances radiosensitivity in glioblastoma cells. Transl Res 2018; 202:99-108. [PMID: 30080989 DOI: 10.1016/j.trsl.2018.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 06/23/2018] [Accepted: 07/10/2018] [Indexed: 11/30/2022]
Abstract
Adrenocortical dysplasia (ACD) is a shelterin protein involved in the maintenance of telomere length and in cancer radioresistance. This study investigated the expression profile of ACD in human gliomas and its role in radioresistance of glioma cells. The expression of ACD was analyzed in 62 different grades of glioma tissues and correlated with prognosis. A radioresistant cell line was generated from U87MG cells. For mechanistic studies, ACD was inhibited by small interfering RNA-targeting ACD and the effect on cell radioresistance, telomerase activity, cyclinD1, caspase-3, hTERT, and BIRC1 was evaluated. Clonogenic assay was performed after irradiation, to investigate the effect of ACD silencing on radiation sensitivity. ACD expression appeared strongly upregulated in higher grade gliomas, and its expression was significantly correlated to grading and poor prognosis. In glioma cell lines, ACD expression pattern was similar to those observed in glioma tissues. In irradiated cells, ACD expression was increased in an ionizing radiation dose-dependent manner. A higher expression of ACD was observed in the radioresistant clones than parental cells. Silencing of ACD led to the enhanced radiation sensitivity, decreased telomerase activity and cyclin D1 expression, reduced expression of BIRC1, and finally to the upregulation of caspase-3. This study represents the first report, which demonstrated the expression pattern of ACD in gliomas and its prognostic value. Our results suggested that ACD is involved in glioblastoma radioresistance, likely through the modulation of telomerase activity, proliferation, and apoptosis. ACD might represent a potential molecular biomarker and a novel therapeutic target in glioblastoma.
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Affiliation(s)
- Francesca Polito
- Department of Biomedical, Dental Sciences and of Morphological and Functional Images, University of Messina, Italy
| | - Maria Cucinotta
- Department of Clinical and Experimental Medicine, University of Messina, Italy
| | - Rosaria V Abbritti
- Department of Biomedical, Dental Sciences and of Morphological and Functional Images, University of Messina, Italy
| | - Anna Brogna
- Department of Biomedical, Dental Sciences and of Morphological and Functional Images, University of Messina, Italy
| | - Stefano Pergolizzi
- Department of Biomedical, Dental Sciences and of Morphological and Functional Images, University of Messina, Italy
| | - Chiara Tomasello
- Department of Biomedical, Dental Sciences and of Morphological and Functional Images, University of Messina, Italy
| | | | - Flavio F Angileri
- Department of Biomedical, Dental Sciences and of Morphological and Functional Images, University of Messina, Italy
| | | | - Alfredo Conti
- Department of Biomedical, Dental Sciences and of Morphological and Functional Images, University of Messina, Italy
| | - Domenico La Torre
- Department of Biomedical, Dental Sciences and of Morphological and Functional Images, University of Messina, Italy
| | - Antonino Germanò
- Department of Biomedical, Dental Sciences and of Morphological and Functional Images, University of Messina, Italy
| | - M'hammed Aguennouz
- Department of Clinical and Experimental Medicine, University of Messina, Italy.
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24
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Ferrara-Romeo I, Martínez P, Blasco MA. Mice lacking RAP1 show early onset and higher rates of DEN-induced hepatocellular carcinomas in female mice. PLoS One 2018; 13:e0204909. [PMID: 30307978 PMCID: PMC6187989 DOI: 10.1371/journal.pone.0204909] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 09/17/2018] [Indexed: 02/07/2023] Open
Abstract
RAP1, a component of the telomere-protective shelterin complex, has been shown to have both telomeric and non-telomeric roles. In the liver, RAP1 is involved in the regulation of metabolic transcriptional programs. RAP1-deficient mice develop obesity and hepatic steatosis, these phenotypes being more severe in females than in males. As hepatic steatosis and obesity have been related to increased liver cancer in mice and humans, we set out to address whether RAP1 deficiency resulted in increased liver cancer upon chemical liver carcinogenesis. We found that Rap1-/- females were more susceptible to DEN-induced liver damage and hepatocellular carcinoma (HCC). DEN-treated Rap1-/- female livers showed an earlier onset of both premalignant and malignant liver lesions, which were characterized by increased abundance of γH2AX-positive cells, increased proliferation and shorter telomeres. These findings highlight an important role for RAP1 in protection from liver damage and liver cancer.
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Affiliation(s)
- Iole Ferrara-Romeo
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, Spain
| | - Paula Martínez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, Spain
| | - Maria A. Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, Spain
- * E-mail:
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25
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Abstract
For more than a decade, it has been known that mammalian cells use shelterin to protect chromosome ends. Much progress has been made on the mechanism by which shelterin prevents telomeres from inadvertently activating DNA damage signaling and double-strand break (DSB) repair pathways. Shelterin averts activation of three DNA damage response enzymes [the ataxia-telangiectasia-mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) kinases and poly(ADP-ribose) polymerase 1 (PARP1)], blocks three DSB repair pathways [classical nonhomologous end joining (c-NHEJ), alternative (alt)-NHEJ, and homology-directed repair (HDR)], and prevents hyper-resection at telomeres. For several of these functions, mechanistic insights have emerged. In addition, much has been learned about how shelterin maintains the telomeric 3' overhang, forms and protects the t-loop structure, and promotes replication through telomeres. These studies revealed that shelterin is compartmentalized, with individual subunits dedicated to distinct aspects of the end-protection problem. This review focuses on the current knowledge of shelterin-mediated telomere protection, highlights differences between human and mouse shelterin, and discusses some of the questions that remain.
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Affiliation(s)
- Titia de Lange
- Laboratory of Cell Biology and Genetics, Rockefeller University, New York, NY 10065, USA;
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26
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Abstract
PURPOSE OF REVIEW Telomere attrition and dysfunction has become a well established pathway involved in organismal aging, not only because it imposes a limitation to cell division and therefore, tissue regeneration but also because telomere homeostasis influences other pathways involved in aging. However, the implication of telomere biology in ovarian aging and fertility is barely starting to be unveiled. RECENT FINDINGS During the last years, mounting evidence in favor of the relationship between the accumulation of short telomeres and ovarian senescence has emerged. Telomere attrition and the loss of telomerase activity in ovarian cell types is a common characteristic of female infertility. SUMMARY Recent findings regarding telomere attrition in the ovary open the possibility of both, finding new molecular biomarkers related to telomere homeostasis that make possible the early detection of ovarian dysfunction before the ovarian reserve has vanished, and the search of new therapies to preserve or set up ovarian cell types so that new and better quality oocytes can be generated in aged ovaries to improve IVF outcomes.
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Brazvan B, Ebrahimi-Kalan A, Velaei K, Mehdipour A, Aliyari Serej Z, Ebrahimi A, Ghorbani M, Cheraghi O, Nozad Charoudeh H. Telomerase activity and telomere on stem progeny senescence. Biomed Pharmacother 2018; 102:9-17. [PMID: 29547744 DOI: 10.1016/j.biopha.2018.02.073] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 02/03/2018] [Accepted: 02/19/2018] [Indexed: 12/19/2022] Open
Abstract
The end of linear chromosomes is formed of a special nucleoprotein heterochromatin structure with repetitive TTAGGG sequences called telomere. Telomere length is regulated by a special enzyme called telomerase, a specific DNA polymerase that adds new telomeric sequences to the chromosome ends. Telomerase consists of two parts; the central protein part and the accessory part which is a RNA component transported by the central part. Regulation of telomere length by this enzyme is a multi-stage process. Telomere length elongation is strongly influenced by the level of telomerase and has a strong correlation with the activity of telomerase enzyme. Human Telomerase Reverse Transcriptase (hTERT) gene expression plays an important role in maintaining telomere length and high proliferative property of cells. Except a low activity of telomerase enzyme in hematopoietic and few types of stem cells, most of somatic cells didn't showed telomerase activity. Moreover, cytokines are secretory proteins that control many aspects of hematopoiesis, especially immune responses and inflammation. Also, the induction of hTERT gene expression by cytokines is organized through the PI3K/AKT and NF/kB signaling pathways. In this review we have tried to talk about effects of immune cell cytokines on telomerase expression/telomere length and the induction of telomerase expression by cytokines.
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Affiliation(s)
- Balal Brazvan
- Department of Basic Sciences, School of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran
| | - Abbas Ebrahimi-Kalan
- Department of Neurosciences and Cognition, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran; Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Kobra Velaei
- Department of Anatomical Science, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ahmad Mehdipour
- Department of Tissue Engineering, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran; Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Zeynab Aliyari Serej
- Applied Cell Sciences Department, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran; Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ayyub Ebrahimi
- Department of Molecular Biology and Genetic, Faculty of Arts and Sciences, Halic Uuniversity, Istanbul, Turkey
| | - Mohammad Ghorbani
- Department of Basic Sciences, School of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran
| | - Omid Cheraghi
- Department of Biochemistry, Faculty of Biological Science, Tarbiat Modares University, Tehran, Iran.
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Stewart JA, Wang Y, Ackerson SM, Schuck PL. Emerging roles of CST in maintaining genome stability and human disease. Front Biosci (Landmark Ed) 2018; 23:1564-1586. [PMID: 29293451 DOI: 10.2741/4661] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The human CTC1-STN1-TEN1 (CST) complex is a single-stranded DNA binding protein that shares homology with RPA and interacts with DNA polymerase alpha/primase. CST complexes are conserved from yeasts to humans and function in telomere maintenance. A common role of CST across species is in the regulation of telomere extension by telomerase and C-strand fill-in synthesis. However, recent studies also indicate that CST promotes telomere duplex replication as well the rescue of stalled DNA replication at non-telomeric sites. Furthermore, CST dysfunction and mutation is associated with several genetic diseases and cancers. In this review, we will summarize what is known about CST with a particular focus on the emerging roles of CST in DNA replication and human disease.
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Affiliation(s)
- Jason A Stewart
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA,
| | - Yilin Wang
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Stephanie M Ackerson
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Percy Logan Schuck
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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29
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Current Perspectives of Telomerase Structure and Function in Eukaryotes with Emerging Views on Telomerase in Human Parasites. Int J Mol Sci 2018; 19:ijms19020333. [PMID: 29364142 PMCID: PMC5855555 DOI: 10.3390/ijms19020333] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/10/2018] [Accepted: 01/17/2018] [Indexed: 12/11/2022] Open
Abstract
Replicative capacity of a cell is strongly correlated with telomere length regulation. Aberrant lengthening or reduction in the length of telomeres can lead to health anomalies, such as cancer or premature aging. Telomerase is a master regulator for maintaining replicative potential in most eukaryotic cells. It does so by controlling telomere length at chromosome ends. Akin to cancer cells, most single-cell eukaryotic pathogens are highly proliferative and require persistent telomerase activity to maintain constant length of telomere and propagation within their host. Although telomerase is key to unlimited cellular proliferation in both cases, not much was known about the role of telomerase in human parasites (malaria, Trypanosoma, etc.) until recently. Since telomerase regulation is mediated via its own structural components, interactions with catalytic reverse transcriptase and several factors that can recruit and assemble telomerase to telomeres in a cell cycle-dependent manner, we compare and discuss here recent findings in telomerase biology in cancer, aging and parasitic diseases to give a broader perspective of telomerase function in human diseases.
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Derevyanko A, Whittemore K, Schneider RP, Jiménez V, Bosch F, Blasco MA. Gene therapy with the TRF1 telomere gene rescues decreased TRF1 levels with aging and prolongs mouse health span. Aging Cell 2017; 16:1353-1368. [PMID: 28944611 PMCID: PMC5676056 DOI: 10.1111/acel.12677] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2017] [Indexed: 12/18/2022] Open
Abstract
The shelterin complex protects telomeres by preventing them from being degraded and recognized as double‐strand DNA breaks. TRF1 is an essential component of shelterin, with important roles in telomere protection and telomere replication. We previously showed that TRF1 deficiency in the context of different mouse tissues leads to loss of tissue homeostasis owing to impaired stem cell function. Here, we show that TRF1 levels decrease during organismal aging both in mice and in humans. We further show that increasing TRF1 expression in both adult (1‐year‐old) and old (2‐year‐old) mice using gene therapy can delay age‐associated pathologies. To this end, we used the nonintegrative adeno‐associated serotype 9 vector (AAV9), which transduces the majority of mouse tissues allowing for moderate and transient TRF1 overexpression. AAV9‐TRF1 gene therapy significantly prevented age‐related decline in neuromuscular function, glucose tolerance, cognitive function, maintenance of subcutaneous fat, and chronic anemia. Interestingly, although AAV9‐TRF1 treatment did not significantly affect median telomere length, we found a lower abundance of short telomeres and of telomere‐associated DNA damage in some tissues. Together, these findings suggest that rescuing naturally decreased TRF1 levels during mouse aging using AAV9‐TRF1 gene therapy results in an improved mouse health span.
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Affiliation(s)
- Aksinya Derevyanko
- Telomeres and Telomerase Group Molecular Oncology Program Spanish National Cancer Centre (CNIO) Melchor Fernández Almagro 3 Madrid E‐28029 Spain
| | - Kurt Whittemore
- Telomeres and Telomerase Group Molecular Oncology Program Spanish National Cancer Centre (CNIO) Melchor Fernández Almagro 3 Madrid E‐28029 Spain
| | - Ralph P. Schneider
- Telomeres and Telomerase Group Molecular Oncology Program Spanish National Cancer Centre (CNIO) Melchor Fernández Almagro 3 Madrid E‐28029 Spain
| | - Verónica Jiménez
- Center of Animal Biotechnology and Gene Therapy Department of Biochemistry and Molecular Biology School of Veterinary Medicine Universitat Autònoma de Barcelona Bellaterra 08193 Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) Madrid Spain
| | - Fàtima Bosch
- Center of Animal Biotechnology and Gene Therapy Department of Biochemistry and Molecular Biology School of Veterinary Medicine Universitat Autònoma de Barcelona Bellaterra 08193 Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) Madrid Spain
| | - Maria A. Blasco
- Telomeres and Telomerase Group Molecular Oncology Program Spanish National Cancer Centre (CNIO) Melchor Fernández Almagro 3 Madrid E‐28029 Spain
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31
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Bejarano L, Schuhmacher AJ, Méndez M, Megías D, Blanco-Aparicio C, Martínez S, Pastor J, Squatrito M, Blasco MA. Inhibition of TRF1 Telomere Protein Impairs Tumor Initiation and Progression in Glioblastoma Mouse Models and Patient-Derived Xenografts. Cancer Cell 2017; 32:590-607.e4. [PMID: 29136505 DOI: 10.1016/j.ccell.2017.10.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/28/2017] [Accepted: 10/07/2017] [Indexed: 01/18/2023]
Abstract
Glioblastoma multiforme (GBM) is a deadly and common brain tumor. Poor prognosis is linked to high proliferation and cell heterogeneity, including glioma stem cells (GSCs). Telomere genes are frequently mutated. The telomere binding protein TRF1 is essential for telomere protection, and for adult and pluripotent stem cells. Here, we find TRF1 upregulation in mouse and human GBM. Brain-specific Trf1 genetic deletion in GBM mouse models inhibited GBM initiation and progression, increasing survival. Trf1 deletion increased telomeric DNA damage and reduced proliferation and stemness. TRF1 chemical inhibitors mimicked these effects in human GBM cells and also blocked tumor sphere formation and tumor growth in xenografts from patient-derived primary GSCs. Thus, targeting telomeres throughout TRF1 inhibition is an effective therapeutic strategy for GBM.
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Affiliation(s)
- Leire Bejarano
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, Madrid, 28029, Spain
| | - Alberto J Schuhmacher
- Seve-Ballesteros Foundation Brain Tumor Group, Cancer Cell Biology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, 28029, Spain
| | - Marinela Méndez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, Madrid, 28029, Spain
| | - Diego Megías
- Confocal Microscopy Unit, Biotechnology Program, Spanish National Cancer Research Centre (CNIO), Madrid, 28029 Spain
| | - Carmen Blanco-Aparicio
- Experimental Therapeutics Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, 28029, Spain
| | - Sonia Martínez
- Experimental Therapeutics Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, 28029, Spain
| | - Joaquín Pastor
- Experimental Therapeutics Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, 28029, Spain
| | - Massimo Squatrito
- Seve-Ballesteros Foundation Brain Tumor Group, Cancer Cell Biology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, 28029, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, Madrid, 28029, Spain.
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32
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Kim H, Li F, He Q, Deng T, Xu J, Jin F, Coarfa C, Putluri N, Liu D, Songyang Z. Systematic analysis of human telomeric dysfunction using inducible telosome/shelterin CRISPR/Cas9 knockout cells. Cell Discov 2017; 3:17034. [PMID: 28955502 PMCID: PMC5613224 DOI: 10.1038/celldisc.2017.34] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 07/27/2017] [Indexed: 01/14/2023] Open
Abstract
CRISPR/Cas9 technology enables efficient loss-of-function analysis of human genes using
somatic cells. Studies of essential genes, however, require conditional knockout (KO)
cells. Here, we describe the generation of inducible CRISPR KO human cell lines for the
subunits of the telosome/shelterin complex, TRF1, TRF2, RAP1, TIN2, TPP1 and POT1, which
directly interact with telomeres or can bind to telomeres through association with other
subunits. Homozygous inactivation of several subunits is lethal in mice, and most
loss-of-function studies of human telomere regulators have relied on RNA
interference-mediated gene knockdown, which suffers its own limitations. Our inducible
CRISPR approach has allowed us to more expediently obtain large numbers of KO cells in
which essential telomere regulators have been inactivated for biochemical and molecular
studies. Our systematic analysis revealed functional differences between human and mouse
telomeric proteins in DNA damage responses, telomere length and metabolic control,
providing new insights into how human telomeres are maintained.
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Affiliation(s)
- Hyeung Kim
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Feng Li
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Quanyuan He
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Tingting Deng
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jun Xu
- Cell-Based Assay Screening Service Core, Baylor College of Medicine, Houston, TX, USA
| | - Feng Jin
- Department of Molecular and Cellular Biology and Advanced Technology Core, Baylor College of Medicine, Houston, TX, USA
| | - Cristian Coarfa
- Department of Molecular and Cellular Biology and Advanced Technology Core, Baylor College of Medicine, Houston, TX, USA
| | - Nagireddy Putluri
- Department of Molecular and Cellular Biology and Advanced Technology Core, Baylor College of Medicine, Houston, TX, USA
| | - Dan Liu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA.,Cell-Based Assay Screening Service Core, Baylor College of Medicine, Houston, TX, USA
| | - Zhou Songyang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA.,Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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33
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Martínez P, Blasco MA. Telomere-driven diseases and telomere-targeting therapies. J Cell Biol 2017; 216:875-887. [PMID: 28254828 PMCID: PMC5379954 DOI: 10.1083/jcb.201610111] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/03/2017] [Accepted: 01/09/2017] [Indexed: 01/19/2023] Open
Abstract
Martínez and Blasco review the molecular mechanisms underlying diseases associated with telomere dysfunction, including telomeropathies, age-related disorders, and cancer. Current and future therapeutic strategies to treat and prevent these diseases, including preclinical development of telomere-targeted therapies using mouse models, are discussed. Telomeres, the protective ends of linear chromosomes, shorten throughout an individual’s lifetime. Telomere shortening is proposed to be a primary molecular cause of aging. Short telomeres block the proliferative capacity of stem cells, affecting their potential to regenerate tissues, and trigger the development of age-associated diseases. Mutations in telomere maintenance genes are associated with pathologies referred to as telomere syndromes, including Hoyeraal-Hreidarsson syndrome, dyskeratosis congenita, pulmonary fibrosis, aplastic anemia, and liver fibrosis. Telomere shortening induces chromosomal instability that, in the absence of functional tumor suppressor genes, can contribute to tumorigenesis. In addition, mutations in telomere length maintenance genes and in shelterin components, the protein complex that protects telomeres, have been found to be associated with different types of cancer. These observations have encouraged the development of therapeutic strategies to treat and prevent telomere-associated diseases, namely aging-related diseases, including cancer. Here we review the molecular mechanisms underlying telomere-driven diseases and highlight recent advances in the preclinical development of telomere-targeted therapies using mouse models.
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Affiliation(s)
- Paula Martínez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre, Madrid E-28029, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre, Madrid E-28029, Spain
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Gomez DLM, Armando RG, Cerrudo CS, Ghiringhelli PD, Gomez DE. Telomerase as a Cancer Target. Development of New Molecules. Curr Top Med Chem 2017; 16:2432-40. [PMID: 26873194 PMCID: PMC4997958 DOI: 10.2174/1568026616666160212122425] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 09/15/2015] [Accepted: 10/25/2015] [Indexed: 12/26/2022]
Abstract
Telomeres are the terminal part of the chromosome containing a long repetitive and non-codifying sequence that has as function protecting the chromosomes. In normal cells, telomeres lost part of such repetitive sequence in each mitosis, until telomeres reach a critical point, triggering at that time senescence and cell death. However, in most of tumor cells in each cell division a part of the telomere is lost, however the appearance of an enzyme called telomerase synthetize the segment that just has been lost, therefore conferring to tumor cells the immortality hallmark. Telomerase is significantly overexpressed in 80–95% of all malignant tumors, being present at low levels in few normal cells, mostly stem cells. Due to these characteristics, telomerase has become an attractive target for new and more effective anticancer agents. The capability of inhibiting telomerase in tumor cells should lead to telomere shortening, senescence and apoptosis. In this work, we analyze the different strategies for telomerase inhibition, either in development, preclinical or clinical stages taking into account their strong points and their caveats. We covered strategies such as nucleosides analogs, oligonucleotides, small molecule inhibitors, G-quadruplex stabilizers, immunotherapy, gene therapy, molecules that affect the telomere/telomerase associated proteins, agents from microbial sources, among others, providing a balanced evaluation of the status of the inhibitors of this powerful target together with an analysis of the challenges ahead.
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Affiliation(s)
| | | | | | | | - D E Gomez
- Laboratory of Molecular Oncology, Department of Science and Technology. Quilmes National University, Bernal, Buenos Aires, Argentina. R. Saenz Peña 352, (1876) Buenos Aires, Argentina.
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Endogenous Telomerase Reverse Transcriptase N-Terminal Tagging Affects Human Telomerase Function at Telomeres In Vivo. Mol Cell Biol 2017; 37:MCB.00541-16. [PMID: 27872149 DOI: 10.1128/mcb.00541-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/15/2016] [Indexed: 12/27/2022] Open
Abstract
Telomerase action at telomeres is essential for the immortal phenotype of stem cells and the aberrant proliferative potential of cancer cells. Insufficient telomere maintenance can cause stem cell and tissue failure syndromes, while increased telomerase levels are associated with tumorigenesis. Both pathologies can arise from only small perturbation of telomerase function. To analyze telomerase at its low endogenous expression level, we genetically engineered human pluripotent stem cells (hPSCs) to express various N-terminal fusion proteins of the telomerase reverse transcriptase from its endogenous locus. Using this approach, we found that these modifications can perturb telomerase function in hPSCs and cancer cells, resulting in telomere length defects. Biochemical analysis suggests that this defect is multileveled, including changes in expression and activity. These findings highlight the unknown complexity of telomerase structural requirements for expression and function in vivo.
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36
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Ehrmann C, Schneider MR. Genetically modified laboratory mice with sebaceous glands abnormalities. Cell Mol Life Sci 2016; 73:4623-4642. [PMID: 27457558 PMCID: PMC11108334 DOI: 10.1007/s00018-016-2312-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/12/2016] [Accepted: 07/19/2016] [Indexed: 12/19/2022]
Abstract
Sebaceous glands (SG) are exocrine glands that release their product by holocrine secretion, meaning that the whole cell becomes a secretion following disruption of the membrane. SG may be found in association with a hair follicle, forming the pilosebaceous unit, or as modified SG at different body sites such as the eyelids (Meibomian glands) or the preputial glands. Depending on their location, SG fulfill a number of functions, including protection of the skin and fur, thermoregulation, formation of the tear lipid film, and pheromone-based communication. Accordingly, SG abnormalities are associated with several diseases such as acne, cicatricial alopecia, and dry eye disease. An increasing number of genetically modified laboratory mouse lines develop SG abnormalities, and their study may provide important clues regarding the molecular pathways regulating SG development, physiology, and pathology. Here, we summarize in tabulated form the available mouse lines with SG abnormalities and, focusing on selected examples, discuss the insights they provide into SG biology and pathology. We hope this survey will become a helpful information source for researchers with a primary interest in SG but also as for researchers from unrelated fields that are unexpectedly confronted with a SG phenotype in newly generated mouse lines.
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Affiliation(s)
- Carmen Ehrmann
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, Feodor-Lynen-Str. 25, 81377, Munich, Germany
| | - Marlon R Schneider
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, Feodor-Lynen-Str. 25, 81377, Munich, Germany.
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37
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Abstract
Telomeres are nucleoprotein complexes that maintain the ends of our chromosomes thus providing genomic stability. Telomerase is a ribonucleoprotein reverse transcriptase that replicates the short tandem repeats of DNA known as telomeres. The telomeric DNA is specifically associated with two major complexes, the shelterin and CST complexes both of which are involved in telomere length regulation and maintenance along with telomerase. Obtaining structural information on these nucleoprotein complexes has been a major bottleneck in fully understanding the mechanism of action of telomeric nucleoproteins for over two decades. The recent advances in molecular and structural biology have enabled us to obtain atomic resolution structures of telomeric proteins alone and in complex with their nucleic acid substrates transforming the field and our understanding and interpretation of this unique biological pathway. Here we report our approach to obtain the structure of the Triobolium castaneum catalytic subunit of telomerase TERT (tcTERT) in its apo- and substrate-bound states.
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Affiliation(s)
- H Hoffman
- The Wistar Institute, Philadelphia, PA, United States
| | - E Skordalakes
- The Wistar Institute, Philadelphia, PA, United States.
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38
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Jones M, Bisht K, Savage SA, Nandakumar J, Keegan CE, Maillard I. The shelterin complex and hematopoiesis. J Clin Invest 2016; 126:1621-9. [PMID: 27135879 DOI: 10.1172/jci84547] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mammalian chromosomes terminate in stretches of repetitive telomeric DNA that act as buffers to avoid loss of essential genetic information during end-replication. A multiprotein complex known as shelterin prevents recognition of telomeric sequences as sites of DNA damage. Telomere erosion contributes to human diseases ranging from BM failure to premature aging syndromes and cancer. The role of shelterin telomere protection is less understood. Mutations in genes encoding the shelterin proteins TRF1-interacting nuclear factor 2 (TIN2) and adrenocortical dysplasia homolog (ACD) were identified in dyskeratosis congenita, a syndrome characterized by somatic stem cell dysfunction in multiple organs leading to BM failure and other pleiotropic manifestations. Here, we introduce the biochemical features and in vivo effects of individual shelterin proteins, discuss shelterin functions in hematopoiesis, and review emerging knowledge implicating the shelterin complex in hematological disorders.
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39
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Donati B, Valenti L. Telomeres, NAFLD and Chronic Liver Disease. Int J Mol Sci 2016; 17:383. [PMID: 26999107 PMCID: PMC4813240 DOI: 10.3390/ijms17030383] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 12/14/2022] Open
Abstract
Telomeres consist of repeat DNA sequences located at the terminal portion of chromosomes that shorten during mitosis, protecting the tips of chromosomes. During chronic degenerative conditions associated with high cell replication rate, progressive telomere attrition is accentuated, favoring senescence and genomic instability. Several lines of evidence suggest that this process is involved in liver disease progression: (a) telomere shortening and alterations in the expression of proteins protecting the telomere are associated with cirrhosis and hepatocellular carcinoma; (b) advanced liver damage is a feature of a spectrum of genetic diseases impairing telomere function, and inactivating germline mutations in the telomerase complex (including human Telomerase Reverse Transcriptase (hTERT) and human Telomerase RNA Component (hTERC)) are enriched in cirrhotic patients independently of the etiology; and (c) experimental models suggest that telomerase protects from liver fibrosis progression. Conversely, reactivation of telomerase occurs during hepatocarcinogenesis, allowing the immortalization of the neoplastic clone. The role of telomere attrition may be particularly relevant in the progression of nonalcoholic fatty liver, an emerging cause of advanced liver disease. Modulation of telomerase or shelterins may be exploited to prevent liver disease progression, and to define specific treatments for different stages of liver disease.
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Affiliation(s)
- Benedetta Donati
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Policlinico Milano, 20122 Milano, Italy.
| | - Luca Valenti
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Policlinico Milano, 20122 Milano, Italy.
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40
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Abstract
During development, cells transition from a pluripotent to a differentiated state, generating all the different types of cells in the body. Development is generally considered an irreversible process, meaning that a differentiated cell is thought to be unable to return to the pluripotent state. However, it is now possible to reprogram mature cells to pluripotency. It is generally thought that reprogramming is accomplished by reversing the natural developmental differentiation process, suggesting that the two mechanisms are closely related. Therefore, a detailed study of cell reprogramming has the potential to shed light on unexplained developmental mechanisms and, conversely, a better understanding of developmental differentiation can help improve cell reprogramming. However, fundamental differences between reprogramming processes and multi-lineage specification during early embryonic development have also been uncovered. In addition, there are multiple routes by which differentiated cells can re-enter the pluripotent state. In this Review, we discuss the connections and disparities between differentiation and reprogramming, and assess the degree to which reprogramming can be considered as a simple reversal of development.
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Affiliation(s)
- Kazutoshi Takahashi
- Center for iPS Cell Research and Application, Kyoto University, Kyoto 606-8507, Japan Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA
| | - Shinya Yamanaka
- Center for iPS Cell Research and Application, Kyoto University, Kyoto 606-8507, Japan Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA
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41
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Abstract
Telomeres, the protective ends of linear chromosomes, shorten throughout an individual's lifetime. Telomere shortening is a hallmark of molecular aging and is associated with premature appearance of diseases associated with aging. Here, we discuss the role of telomere shortening as a direct cause for aging and age-related diseases. In particular, we draw attention to the fact that telomere length influences longevity. Furthermore, we discuss intrinsic and environmental factors that can impact on human telomere erosion. Finally, we highlight recent advances in telomerase-based therapeutic strategies for the treatment of diseases associated with extremely short telomeres owing to mutations in telomerase, as well as age-related diseases, and ultimately aging itself.
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Affiliation(s)
- Christian Bär
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
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42
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Witkowska A, Strzalka-Mrozik B, Owczarek A, Gola J, Mazurek U, Grzeszczak W, Gumprecht J. Downregulation of telomerase maintenance-related ACD expression in patients undergoing immunosuppresive therapy following kidney transplantation. Exp Ther Med 2015; 10:2224-2230. [PMID: 26668621 DOI: 10.3892/etm.2015.2785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 07/23/2015] [Indexed: 11/06/2022] Open
Abstract
Chronic administration of immunosuppressants has been associated with long-term consequences, including a higher risk of neoplasm development. The processes regulating telomere function exert a major influence on human cancer biology. The present study aimed to assess the effect of immunosuppressive therapy on the expression of genes associated with telomere maintenance and protection in patients following renal transplantation. A total of 51 patients that had undergone kidney transplantation and 54 healthy controls were enrolled in the study. The 51 transplant patients received a three-drug immunosuppressive regimen consisting of cyclosporine A, prednisone and mycophenolate mofetil. In stage 1 of the study, the expression profiles of 123 transcripts, which represented 70 genes, were assessed in peripheral mononuclear blood cells using an oligonucleotide microarray technique in 8 transplant recipients and 4 healthy control subjects. Among the analyzed transcripts, the expression levels of 4 differed significantly between the studied groups; however, only the ACD (adrenocortical dysplasia homolog) gene, encoding the telomere-binding protein POT1-interacting protein 1 (TPP1), was sufficiently specific for telomere homeostasis. The expression of ACD was downregulated in transplant recipients (fold change, 2.11; P=0.006). In stage 2 of the study, reverse transcription-quantitative polymerase chain reaction analysis of ACD, DKC1 and hTERT mRNA was conducted for all transplant patients and control subjects. The results confirmed the downregulation of the ACD gene in patients that had received immunosuppressive therapy (P=0.002). The results of the present study indicate that the downregulation of ACD gene transcription, and thus TPP1 protein expression, may enhance the capacity for cell immortalization, despite normal levels of other key telomere maintenance factors, in patients undergoing immunosuppressive therapy. Furthermore, the results indicate that TPP1 has potential for use as an early clinical marker and/or therapeutic target for cancer in patients following organ transplantation.
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Affiliation(s)
- Agnieszka Witkowska
- Department of Internal Medicine, Diabetology and Nephrology, Medical University of Silesia, 41-800 Zabrze, Silesia, Poland
| | - Barbara Strzalka-Mrozik
- Department of Molecular Biology, Medical University of Silesia, 41-200 Sosnowiec, Silesia, Poland
| | - Aleksander Owczarek
- Division of Statistics, Medical University of Silesia, 41-200 Sosnowiec, Silesia, Poland
| | - Joanna Gola
- Department of Molecular Biology, Medical University of Silesia, 41-200 Sosnowiec, Silesia, Poland
| | - Urszula Mazurek
- Department of Molecular Biology, Medical University of Silesia, 41-200 Sosnowiec, Silesia, Poland
| | - Wladyslaw Grzeszczak
- Department of Internal Medicine, Diabetology and Nephrology, Medical University of Silesia, 41-800 Zabrze, Silesia, Poland
| | - Janusz Gumprecht
- Department of Internal Medicine, Diabetology and Nephrology, Medical University of Silesia, 41-800 Zabrze, Silesia, Poland
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43
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Abstract
In this review, Schmidt and Cech cover human telomerase biogenesis, trafficking, and activation, comparing key aspects with the analogous events in other species. Telomerase is the ribonucleoprotein enzyme that catalyzes the extension of telomeric DNA in eukaryotes. Recent work has begun to reveal key aspects of the assembly of the human telomerase complex, its intracellular trafficking involving Cajal bodies, and its recruitment to telomeres. Once telomerase has been recruited to the telomere, it appears to undergo a separate activation step, which may include an increase in its repeat addition processivity. This review covers human telomerase biogenesis, trafficking, and activation, comparing key aspects with the analogous events in other species.
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Affiliation(s)
- Jens C Schmidt
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Thomas R Cech
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80309, USA
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Beier F, Martinez P, Blasco MA. Chronic replicative stress induced by CCl4 in TRF1 knockout mice recapitulates the origin of large liver cell changes. J Hepatol 2015; 63:446-55. [PMID: 25819337 DOI: 10.1016/j.jhep.2015.03.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 03/01/2015] [Accepted: 03/04/2015] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS Large liver cell changes (LLCC) are characterized by pleomorphic large nuclei frequently found in liver diseases as chronic viral hepatitis and liver cirrhosis. The origin of this lesion remains cryptic, but the presence of LLCC is correlated with an increased risk of hepatocellular carcinoma. Telomeric repeat binding factor 1 (TRF1) is part of the shelterin complex and is essential for telomere protection. Ablation of TRF1 induces telomere fragility and fusions and chromosomal instability. METHODS In this study, we addressed the role of TRF1 in liver regeneration generating a mouse model with conditional deletion of TRF1 in the liver. RESULTS TRF1 deletion has no deleterious effects in liver and leads to increased ploidy of hepatocytes after 2/3 hepatectomy. Mice lacking TRF1 in the liver can survive for over one year without any evidence for altered liver function. Importantly, applying chronic replicative stress by frequent carbon tetrachloride (CCl4) injections, TRF1 deleted mice undergo ploidy changes consistent with endoreduplication and develop LLCC like lesions in the liver positive for p21, Cyclin D1 and PCNA as observed in humans. CONCLUSION In summary, we provide mechanistic insight into the role of TRF1 in liver regeneration and provide a mouse model recapitulating the clinical features of LLCC.
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Affiliation(s)
- Fabian Beier
- Telomere and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Madrid, Spain; Department of Hematology, Oncology and Stem Cell Transplantation, University of Aachen, Aachen, Germany
| | - Paula Martinez
- Telomere and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Maria A Blasco
- Telomere and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
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45
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Martínez P, Blasco MA. Replicating through telomeres: a means to an end. Trends Biochem Sci 2015; 40:504-15. [PMID: 26188776 DOI: 10.1016/j.tibs.2015.06.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/08/2015] [Accepted: 06/12/2015] [Indexed: 02/07/2023]
Abstract
Proper replication of the telomeric DNA at chromosome ends is critical for preserving genome integrity. Yet, telomeres present challenges for the replication machinery, such as their repetitive and heterochromatic nature and their potential to form non-Watson-Crick structures as well as the fact that they are transcribed. Numerous telomere-bound proteins are required to facilitate progression of the replication fork throughout telomeric DNA. In particular, shelterin plays crucial functions in telomere length regulation, protection of telomeres from nuclease degradation, control of DNA damage response at telomeres, and the recruitment of associated factors required for telomere DNA processing and replication. In this review we discuss the recently uncovered functions of mammalian telomere-specific and telomere-associated proteins that facilitate proper telomere replication.
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Affiliation(s)
- Paula Martínez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain.
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46
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Tacconi EMC, Tarsounas M. How homologous recombination maintains telomere integrity. Chromosoma 2015; 124:119-30. [PMID: 25430998 DOI: 10.1007/s00412-014-0497-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 11/17/2014] [Accepted: 11/18/2014] [Indexed: 01/13/2023]
Abstract
Telomeres protect the ends of linear chromosomes against loss of genetic information and inappropriate processing as damaged DNA and are therefore crucial to the maintenance of chromosome integrity. In addition to providing a pathway for genome-wide DNA repair, homologous recombination (HR) plays a key role in telomere replication and capping. Consistent with this, the genomic instability characteristic of HR-deficient cells and tumours is driven in part by telomere dysfunction. Here, we discuss the mechanisms by which HR modulates the response to intrinsic cellular challenges that arise during telomere replication, as well as its impact on the assembly of telomere protective structures. How normal and tumour cells differ in their ability to maintain telomeres is deeply relevant to the search for treatments that would selectively eliminate cells whose capacity for HR-mediated repair has been compromised.
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Affiliation(s)
- Eliana M C Tacconi
- Telomere and Genome Stability Group, The CRUK-MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK
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Luo Z, Dai Z, Xie X, Feng X, Liu D, Songyang Z, Xiong Y. TeloPIN: a database of telomeric proteins interaction network in mammalian cells. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2015; 2015:bav018. [PMID: 25792605 PMCID: PMC4365144 DOI: 10.1093/database/bav018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Interaction network surrounding telomeres has been intensively studied during the past two decades. However, no specific resource by integrating telomere interaction information data is currently available. To facilitate the understanding of the molecular interaction network by which telomeres are associated with biological process and diseases, we have developed TeloPIN (Telomeric Proteins Interaction Network) database (http://songyanglab.sysu.edu.cn/telopin/), a novel database that points to provide comprehensive information on protein–protein, protein–DNA and protein–RNA interaction of telomeres. TeloPIN database contains four types of interaction data, including (i) protein–protein interaction (PPI) data, (ii) telomeric proteins ChIP-seq data, (iii) telomere-associated proteins data and (iv) telomeric repeat-containing RNAs (TERRA)-interacting proteins data. By analyzing these four types of interaction data, we found that 358 and 199 proteins have more than one type of interaction information in human and mouse cells, respectively. We also developed table browser and TeloChIP genome browser to help researchers with better integrated visualization of interaction data from different studies. The current release of TeloPIN database includes 1111 PPI, eight telomeric protein ChIP-seq data sets, 1391 telomere-associated proteins and 183 TERRA-interacting proteins from 92 independent studies in mammalian cells. The interaction information provided by TeloPIN database will greatly expand our knowledge of telomeric proteins interaction network. Database URL: TeloPIN database address is http://songyanglab.sysu.edu.cn/telopin. TeloPIN database is freely available to non-commercial use.
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Affiliation(s)
- Zhenhua Luo
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China
| | - Zhiming Dai
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China
| | - Xiaowei Xie
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China
| | - Xuyang Feng
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China
| | - Dan Liu
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX
| | - Zhou Songyang
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX
| | - Yuanyan Xiong
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510006, China, Department of Electronics and Communication Engineering, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, China; SYSU-CMU Shunde International Joint Research Institute (JRI) Shunde, Guangdong, China; Cell-Based Assay Screening Core, Dan L. Duncan Cancer Center, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA, and Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, China
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Harland JL, Chang YT, Moser BA, Nakamura TM. Tpz1-Ccq1 and Tpz1-Poz1 interactions within fission yeast shelterin modulate Ccq1 Thr93 phosphorylation and telomerase recruitment. PLoS Genet 2014; 10:e1004708. [PMID: 25330395 PMCID: PMC4199508 DOI: 10.1371/journal.pgen.1004708] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 08/26/2014] [Indexed: 11/22/2022] Open
Abstract
In both fission yeast and humans, the shelterin complex plays central roles in regulation of telomerase recruitment, protection of telomeres against DNA damage response factors, and formation of heterochromatin at telomeres. While shelterin is essential for limiting activation of the DNA damage checkpoint kinases ATR and ATM at telomeres, these kinases are required for stable maintenance of telomeres. In fission yeast, Rad3ATR and Tel1ATM kinases are redundantly required for telomerase recruitment, since Rad3ATR/Tel1ATM-dependent phosphorylation of the shelterin subunit Ccq1 at Thr93 promotes interaction between Ccq1 and the telomerase subunit Est1. However, it remained unclear how protein-protein interactions within the shelterin complex (consisting of Taz1, Rap1, Poz1, Tpz1, Pot1 and Ccq1) contribute to the regulation of Ccq1 Thr93 phosphorylation and telomerase recruitment. In this study, we identify domains and amino acid residues that are critical for mediating Tpz1-Ccq1 and Tpz1-Poz1 interaction within the fission yeast shelterin complex. Using separation of function Tpz1 mutants that maintain Tpz1-Pot1 interaction but specifically disrupt either Tpz1-Ccq1 or Tpz1-Poz1 interaction, we then establish that Tpz1-Ccq1 interaction promotes Ccq1 Thr93 phosphorylation, telomerase recruitment, checkpoint inhibition and telomeric heterochromatin formation. Furthermore, we demonstrate that Tpz1-Poz1 interaction promotes telomere association of Poz1, and loss of Poz1 from telomeres leads to increases in Ccq1 Thr93 phosphorylation and telomerase recruitment, and telomeric heterochromatin formation defect. In addition, our studies establish that Tpz1-Poz1 and Tpz1-Ccq1 interactions redundantly fulfill the essential telomere protection function of the shelterin complex, since simultaneous loss of both interactions caused immediate loss of cell viability for the majority of cells and generation of survivors with circular chromosomes. Based on these findings, we suggest that the negative regulatory function of Tpz1-Poz1 interaction works upstream of Rad3ATR kinase, while Tpz1-Ccq1 interaction works downstream of Rad3ATR kinase to facilitate Ccq1 Thr93 phosphorylation and telomerase recruitment. Proper maintenance of telomeres is essential for maintaining genomic stability, and genomic instability caused by dysfunctional telomeres could lead to accumulation of mutations that may drive tumor formation. Telomere dysfunction has also been linked to premature aging caused by depletion of stem cells. Therefore, it is important to understand how cells ensure proper maintenance of telomeres. Mammalian cells and fission yeast cells utilize an evolutionarily conserved multi-subunit telomere protection complex called shelterin to ensure protection against telomere fusions by DNA repair factors and cell cycle arrest by DNA damage checkpoint kinases. However, previous studies have not yet fully established how protein-protein interactions within the shelterin complex contribute to the regulation of DNA damage checkpoint signaling and telomerase recruitment. By utilizing separation of function mutations that specifically disrupt either Tpz1-Ccq1 or Tpz1-Poz1 interaction within the fission yeast shelterin, we establish that Tpz1-Ccq1 interaction is essential for phosphorylation of Ccq1 by the DNA damage checkpoint kinases Rad3ATR and Tel1ATM that is needed for telomerase recruitment to telomeres, while Tpz1-Poz1 interaction prevents Ccq1 phosphorylation by promoting Poz1 association with telomeres. These findings thus establish for the first time how protein-protein interactions within the shelterin complex modulate checkpoint kinase-dependent phosphorylation essential for telomerase recruitment.
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Affiliation(s)
- Jennifer L. Harland
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Ya-Ting Chang
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Bettina A. Moser
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Toru M. Nakamura
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
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49
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Kocak H, Ballew BJ, Bisht K, Eggebeen R, Hicks BD, Suman S, O'Neil A, Giri N, Maillard I, Alter BP, Keegan CE, Nandakumar J, Savage SA. Hoyeraal-Hreidarsson syndrome caused by a germline mutation in the TEL patch of the telomere protein TPP1. Genes Dev 2014; 28:2090-102. [PMID: 25233904 PMCID: PMC4180972 DOI: 10.1101/gad.248567.114] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Germline mutations in telomere biology genes cause dyskeratosis congenita (DC), an inherited bone marrow failure and cancer predisposition syndrome. Hoyeraal-Hreidarsson syndrome (HH) is a clinically severe variant of DC. Using exome sequencing, Kocak et al. identified mutations in ACD (encoding TPP1), a component of the telomeric shelterin complex, in one family affected by HH. Characterization of the mutations revealed that the single-amino-acid deletion affecting the TEL patch surface of the TPP1 protein significantly compromises both telomerase recruitment and processivity. Germline mutations in telomere biology genes cause dyskeratosis congenita (DC), an inherited bone marrow failure and cancer predisposition syndrome. DC is a clinically heterogeneous disorder diagnosed by the triad of dysplastic nails, abnormal skin pigmentation, and oral leukoplakia; Hoyeraal-Hreidarsson syndrome (HH), a clinically severe variant of DC, also includes cerebellar hypoplasia, immunodeficiency, and intrauterine growth retardation. Approximately 70% of DC cases are associated with a germline mutation in one of nine genes, the products of which are all involved in telomere biology. Using exome sequencing, we identified mutations in Adrenocortical Dysplasia Homolog (ACD) (encoding TPP1), a component of the telomeric shelterin complex, in one family affected by HH. The proband inherited a deletion from his father and a missense mutation from his mother, resulting in extremely short telomeres and a severe clinical phenotype. Characterization of the mutations revealed that the single-amino-acid deletion affecting the TEL patch surface of the TPP1 protein significantly compromises both telomerase recruitment and processivity, while the missense mutation in the TIN2-binding region of TPP1 is not as clearly deleterious to TPP1 function. Our results emphasize the critical roles of the TEL patch in proper stem cell function and demonstrate that TPP1 is the second shelterin component (in addition to TIN2) to be implicated in DC.
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Affiliation(s)
- Hande Kocak
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Bari J Ballew
- Division of Cancer Epidemiology and Genetics (DCEG), National Cancer Institute (NCI), Rockville, Maryland 20850, USA
| | - Kamlesh Bisht
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Rebecca Eggebeen
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, NCI-Frederick, Rockville, Maryland 20850, USA
| | - Belynda D Hicks
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, NCI-Frederick, Rockville, Maryland 20850, USA
| | - Shalabh Suman
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, NCI-Frederick, Rockville, Maryland 20850, USA
| | - Adri O'Neil
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, NCI-Frederick, Rockville, Maryland 20850, USA
| | - Neelam Giri
- Division of Cancer Epidemiology and Genetics (DCEG), National Cancer Institute (NCI), Rockville, Maryland 20850, USA
| | | | | | - Ivan Maillard
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA; Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA; Department of Cell and Developmental Biology, Ann Arbor, Michigan 48109, USA
| | - Blanche P Alter
- Division of Cancer Epidemiology and Genetics (DCEG), National Cancer Institute (NCI), Rockville, Maryland 20850, USA
| | - Catherine E Keegan
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan 48109, USA; Department of Pediatrics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Sharon A Savage
- Division of Cancer Epidemiology and Genetics (DCEG), National Cancer Institute (NCI), Rockville, Maryland 20850, USA;
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Direct single-stranded DNA binding by Teb1 mediates the recruitment of Tetrahymena thermophila telomerase to telomeres. Mol Cell Biol 2014; 34:4200-12. [PMID: 25225329 DOI: 10.1128/mcb.01030-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The eukaryotic reverse transcriptase telomerase copies its internal RNA template to synthesize telomeric DNA repeats at chromosome ends in balance with sequence loss during cell proliferation. Previous work has established several factors involved in telomerase recruitment to telomeres in yeast and mammalian cells; however, it remains unclear what determines the association of telomerase with telomeres in other organisms. Here we investigate the cell cycle dependence of telomere binding by each of the seven Tetrahymena thermophila telomerase holoenzyme proteins TERT, p65, Teb1, p50, p75, p45, and p19. We observed coordinate cell cycle-regulated recruitment and release of all of the subunits, including the telomeric-repeat DNA-binding subunit Teb1. Using domain truncation and mutagenesis approaches, we investigated which subunits govern the interaction of telomerase holoenzyme with telomeres. Our results show that Teb1 is critical for telomere interaction of other holoenzyme subunits and demonstrate that high-affinity Teb1 DNA-binding activity is necessary and sufficient for cell cycle-regulated telomere association. Overall, these and additional findings indicate that in the ciliate Tetrahymena, telomerase recruitment to telomeres requires direct binding to single-stranded DNA, unlike the indirect DNA recognition through telomere-bound proteins essential in yeast and mammalian cells.
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